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Sample records for plasma sheet electrons

  1. Observations of Electron Vorticity in the Inner Plasma Sheet

    NASA Technical Reports Server (NTRS)

    Gurgiolo, C.; Goldstein, M. L.; Vinas, A. F.; Matthaeus, W. H.; Fazakerley, A. N.

    2011-01-01

    From a limited number of observations it appears that vorticity is a common feature in the inner plasma sheet. With the four Cluster spacecraft and the four PEACE instruments positioned in a tetrahedral configuration, for the first time it is possible to directly estimate the electron fluid vorticity in a space plasma. We show examples of electron fluid vorticity from multiple plasma sheet crossings. These include three time periods when Cluster passed through a reconnection ion diffusion region. Enhancements in vorticity are seen in association with each crossing of the ion diffusion region.

  2. Transport of the plasma sheet electrons to the geostationary distances

    NASA Astrophysics Data System (ADS)

    Ganushkina, N. Y.; Amariutei, O. A.; Shprits, Y. Y.; Liemohn, M. W.

    2013-01-01

    Abstract<p label="1">The transport and acceleration of low-energy <span class="hlt">electrons</span> (50-250 keV) from the <span class="hlt">plasma</span> <span class="hlt">sheet</span> to the geostationary orbit were investigated. Two moderate storm events, which occurred on 6-7 November 1997 and 12-14 June 2005, were modeled using the Inner Magnetosphere Particle Transport and Acceleration model (IMPTAM) with the boundary set at 10 RE in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. The output of the IMPTAM was compared to the observed <span class="hlt">electron</span> fluxes in four energy ranges (50-225 keV) measured by the Synchronous Orbit Particle Analyzer instrument onboard the Los Alamos National Laboratory spacecraft. It was found that the large-scale convection in combination with substorm-associated impulsive fields is the drivers of the transport of <span class="hlt">plasma</span> <span class="hlt">sheet</span> <span class="hlt">electrons</span> from 10 RE to geostationary orbit at 6.6 RE during storm times. The addition of radial diffusion had no significant influence on the modeled <span class="hlt">electron</span> fluxes. At the same time, the modeled <span class="hlt">electron</span> fluxes are one (two) order(s) smaller than the observed ones for 50-150 keV (150-225 keV) <span class="hlt">electrons</span>, respectively, most likely due to inaccuracy of <span class="hlt">electron</span> boundary conditions. The loss processes due to wave-particle interactions were not considered. The choice of the large-scale convection electric field model used in simulations did not have a significant influence on the modeled <span class="hlt">electron</span> fluxes, since there is not much difference between the equipotential contours given by the Volland-Stern and the Boyle et al. (1997) models at distances from 10 to 6.6 RE in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. Using the TS05 model for the background magnetic field instead of the T96 model resulted in larger deviations of the modeled <span class="hlt">electron</span> fluxes from the observed ones due to specific features of the TS05 model. The increase in the modeled <span class="hlt">electron</span> fluxes can be as large as two orders of magnitude when substorm-associated electromagnetic fields were taken into account. The obtained model distribution of low-energy <span class="hlt">electron</span> fluxes can be used as an input to the radiation belt models. This seed population for radiation belts will affect the local acceleration up to relativistic energies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015RScI...86a3503K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015RScI...86a3503K"><span id="translatedtitle">Experimental investigation of a 1 kA/cm2 <span class="hlt">sheet</span> beam <span class="hlt">plasma</span> cathode <span class="hlt">electron</span> gun</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kumar, Niraj; Narayan Pal, Udit; Kumar Pal, Dharmendra; Prajesh, Rahul; Prakash, Ram</p> <p>2015-01-01</p> <p>In this paper, a cold cathode based <span class="hlt">sheet</span>-beam <span class="hlt">plasma</span> cathode <span class="hlt">electron</span> gun is reported with achieved <span class="hlt">sheet</span>-beam current density ˜1 kA/cm2 from pseudospark based argon <span class="hlt">plasma</span> for pulse length of ˜200 ns in a single shot experiment. For the qualitative assessment of the <span class="hlt">sheet</span>-beam, an arrangement of three isolated metallic-<span class="hlt">sheets</span> is proposed. The actual shape and size of the <span class="hlt">sheet-electron</span>-beam are obtained through a non-conventional method by proposing a dielectric charging technique and scanning <span class="hlt">electron</span> microscope based imaging. As distinct from the earlier developed <span class="hlt">sheet</span> beam sources, the generated <span class="hlt">sheet</span>-beam has been propagated more than 190 mm distance in a drift space region maintaining <span class="hlt">sheet</span> structure without assistance of any external magnetic field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25638082','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25638082"><span id="translatedtitle">Experimental investigation of a 1 kA/cm² <span class="hlt">sheet</span> beam <span class="hlt">plasma</span> cathode <span class="hlt">electron</span> gun.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kumar, Niraj; Pal, Udit Narayan; Pal, Dharmendra Kumar; Prajesh, Rahul; Prakash, Ram</p> <p>2015-01-01</p> <p>In this paper, a cold cathode based <span class="hlt">sheet</span>-beam <span class="hlt">plasma</span> cathode <span class="hlt">electron</span> gun is reported with achieved <span class="hlt">sheet</span>-beam current density ∼1 kA/cm(2) from pseudospark based argon <span class="hlt">plasma</span> for pulse length of ∼200 ns in a single shot experiment. For the qualitative assessment of the <span class="hlt">sheet</span>-beam, an arrangement of three isolated metallic-<span class="hlt">sheets</span> is proposed. The actual shape and size of the <span class="hlt">sheet-electron</span>-beam are obtained through a non-conventional method by proposing a dielectric charging technique and scanning <span class="hlt">electron</span> microscope based imaging. As distinct from the earlier developed <span class="hlt">sheet</span> beam sources, the generated <span class="hlt">sheet</span>-beam has been propagated more than 190 mm distance in a drift space region maintaining <span class="hlt">sheet</span> structure without assistance of any external magnetic field. PMID:25638082</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22025583','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22025583"><span id="translatedtitle">Graphene <span class="hlt">sheets</span> embedded carbon film prepared by <span class="hlt">electron</span> irradiation in <span class="hlt">electron</span> cyclotron resonance <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wang Chao; Diao Dongfeng; Fan Xue; Chen Cheng</p> <p>2012-06-04</p> <p>We used a low energy <span class="hlt">electron</span> irradiation technique to prepare graphene <span class="hlt">sheets</span> embedded carbon (GSEC) film based on <span class="hlt">electron</span> cyclotron resonance <span class="hlt">plasma</span>. The particular {pi} <span class="hlt">electronic</span> structure of the GSEC film similar to bilayer graphene was verified by Raman spectra 2D band analyzing. The phase transition from amorphous carbon to GSEC was initiated when <span class="hlt">electron</span> irradiation energy reached 40 eV, and the growth mechanism of GSEC was interpreted as inelastic scattering of low energy <span class="hlt">electrons</span>. This finding indicates that the GSEC film obtained by low energy <span class="hlt">electron</span> irradiation can be excepted for widely applications with outstanding electric properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...804L...1C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...804L...1C"><span id="translatedtitle">Thin Current <span class="hlt">Sheets</span> and Associated <span class="hlt">Electron</span> Heating in Turbulent Space <span class="hlt">Plasma</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chasapis, A.; Retin, A.; Sahraoui, F.; Vaivads, A.; Khotyaintsev, Yu. V.; Sundkvist, D.; Greco, A.; Sorriso-Valvo, L.; Canu, P.</p> <p>2015-05-01</p> <p>Intermittent structures, such as thin current <span class="hlt">sheets</span>, are abundant in turbulent <span class="hlt">plasmas</span>. Numerical simulations indicate that such current <span class="hlt">sheets</span> are important sites of energy dissipation and particle heating occurring at kinetic scales. However, direct evidence of dissipation and associated heating within current <span class="hlt">sheets</span> is scarce. Here, we show a new statistical study of local <span class="hlt">electron</span> heating within proton-scale current <span class="hlt">sheets</span> by using high-resolution spacecraft data. Current <span class="hlt">sheets</span> are detected using the Partial Variance of Increments (PVI) method which identifies regions of strong intermittency. We find that strong <span class="hlt">electron</span> heating occurs in high PVI (>3) current <span class="hlt">sheets</span> while no significant heating occurs in low PVI cases (<3), indicating that the former are dominant for energy dissipation. Current <span class="hlt">sheets</span> corresponding to very high PVI (>5) show the strongest heating and most of the time are consistent with ongoing magnetic reconnection. This suggests that reconnection is important for <span class="hlt">electron</span> heating and dissipation at kinetic scales in turbulent <span class="hlt">plasmas</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1987steh.rept.....U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1987steh.rept.....U"><span id="translatedtitle">Confinement time of <span class="hlt">electrons</span> and H(-)/D(-) ions in the Uramoto type <span class="hlt">sheet</span> <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Uramoto, Joshin</p> <p>1987-10-01</p> <p>Confinement times of <span class="hlt">electrons</span> and H(-)/D(-) ions in the Uramoto type <span class="hlt">sheet</span> <span class="hlt">plasma</span> as a H(-)/D(-) ion source of volume production are determined from e-folding decay times of negative current to a Langmuir probe, after a discharge for the <span class="hlt">sheet</span> <span class="hlt">plasma</span> production is stopped through SCR connected between the anode and the cathode. The confinement times depend mainly on a bias potential of the metal vacuum chamber outside of the <span class="hlt">sheet</span> <span class="hlt">plasma</span>, which are ranging from about 40 microsec (for plus bias voltage with respect to the anode) to about 300 microsec (for minus bias voltage). Then, in order to extract a volume produced H(-)/D(-) ion current in high efficiency, it is shown that a long confinement time is an important necessary condition with the two necessary conditions (high <span class="hlt">electron</span> density in low <span class="hlt">electron</span> temperature and <span class="hlt">electron</span> beam components) reported already.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19940033533&hterms=earth+layers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dearth%2527s%2Blayers','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19940033533&hterms=earth+layers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dearth%2527s%2Blayers"><span id="translatedtitle"><span class="hlt">Electron</span> generation of electrostatic waves in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Onsager, T. G.; Thomsen, M. F.; Elphic, R. C.; Gosling, J. T.; Anderson, R. R.; Kettmann, G.</p> <p>1993-01-01</p> <p>Broadband electrostatic noise (BEN) has been shown to occur in conjunction with ion beams; extensive investigations of possible ion beam-related instabilities that could generate the observed wave spectra have been conducted. It has also been demonstrated that unstable <span class="hlt">electron</span> distribution functions are sometimes measured in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer. We present simultaneous observations of ion and <span class="hlt">electron</span> distribution functions and electric field wave spectra measured by ISEE 1 and ISEE 2 in the Earth's magnetotail. As the spacecraft moved from the tail lobe toward the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, the fast indication of boundary layer <span class="hlt">plasma</span> was seen in the <span class="hlt">electron</span> distributions, followed some minutes later by the detection of boundary layer ions. The onset of large-amplitude electrostatic waves at frequencies up to the <span class="hlt">electron</span> <span class="hlt">plasma</span> frequency was coincident with the onset of the boundary layer <span class="hlt">electrons</span>, suggesting that broadband electrostatic waves may often be generated by unstable <span class="hlt">electron</span> distributions in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer, particularly the higher frequency portion of the wave spectrum. The observed changes in the <span class="hlt">electron</span> distribution functions indicate that the <span class="hlt">plasma</span> was not heated locally by the waves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19990071231','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990071231"><span id="translatedtitle">Inner Magnetospheric Superthermal <span class="hlt">Electron</span> Transport: Photoelectron and <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> <span class="hlt">Electron</span> Sources</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Khazanov, G. V.; Liemohn, M. W.; Kozyra, J. U.; Moore, T. E.</p> <p>1998-01-01</p> <p>Two time-dependent kinetic models of superthermal <span class="hlt">electron</span> transport are combined to conduct global calculations of the nonthermal <span class="hlt">electron</span> distribution function throughout the inner magnetosphere. It is shown that the energy range of validity for this combined model extends down to the superthermal-thermal intersection at a few eV, allowing for the calculation of the en- tire distribution function and thus an accurate heating rate to the thermal <span class="hlt">plasma</span>. Because of the linearity of the formulas, the source terms are separated to calculate the distributions from the various populations, namely photoelectrons (PEs) and <span class="hlt">plasma</span> <span class="hlt">sheet</span> <span class="hlt">electrons</span> (PSEs). These distributions are discussed in detail, examining the processes responsible for their formation in the various regions of the inner magnetosphere. It is shown that convection, corotation, and Coulomb collisions are the dominant processes in the formation of the PE distribution function and that PSEs are dominated by the interplay between the drift terms. Of note is that the PEs propagate around the nightside in a narrow channel at the edge of the plasmasphere as Coulomb collisions reduce the fluxes inside of this and convection compresses the flux tubes inward. These distributions are then recombined to show the development of the total superthermal <span class="hlt">electron</span> distribution function in the inner magnetosphere and their influence on the thermal <span class="hlt">plasma</span>. PEs usually dominate the dayside heating, with integral energy fluxes to the ionosphere reaching 10(exp 10) eV/sq cm/s in the plasmasphere, while heating from the PSEs typically does not exceed 10(exp 8) eV/sq cm/s. On the nightside, the inner plasmasphere is usually unheated by superthermal <span class="hlt">electrons</span>. A feature of these combined spectra is that the distribution often has upward slopes with energy, particularly at the crossover from PE to PSE dominance, indicating that instabilities are possible.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/4794830','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/4794830"><span id="translatedtitle"><span class="hlt">SHEET</span> <span class="hlt">PLASMA</span> DEVICE</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Henderson, O.A.</p> <p>1962-07-17</p> <p>An ion-<span class="hlt">electron</span> <span class="hlt">plasma</span> heating apparatus of the pinch tube class was developed wherein a <span class="hlt">plasma</span> is formed by an intense arc discharge through a gas and is radially constricted by the magnetic field of the discharge. To avoid kink and interchange instabilities which can disrupt a conventional arc shortiy after it is formed, the apparatus is a pinch tube with a flat configuration for forming a <span class="hlt">sheet</span> of <span class="hlt">plasma</span> between two conductive plates disposed parallel and adjacent to the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. Kink instabilities are suppressed by image currents induced in the conductive plates while the interchange instabilities are neutrally stable because of the flat <span class="hlt">plasma</span> configuration wherein such instabilities may occur but do not dynamically increase in amplitude. (AEC)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22392313','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22392313"><span id="translatedtitle">Experimental investigation of a 1 kA/cm{sup 2} <span class="hlt">sheet</span> beam <span class="hlt">plasma</span> cathode <span class="hlt">electron</span> gun</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kumar, Niraj Narayan Pal, Udit; Prajesh, Rahul; Prakash, Ram; Kumar Pal, Dharmendra</p> <p>2015-01-15</p> <p>In this paper, a cold cathode based <span class="hlt">sheet</span>-beam <span class="hlt">plasma</span> cathode <span class="hlt">electron</span> gun is reported with achieved <span class="hlt">sheet</span>-beam current density ∼1 kA/cm{sup 2} from pseudospark based argon <span class="hlt">plasma</span> for pulse length of ∼200 ns in a single shot experiment. For the qualitative assessment of the <span class="hlt">sheet</span>-beam, an arrangement of three isolated metallic-<span class="hlt">sheets</span> is proposed. The actual shape and size of the <span class="hlt">sheet-electron</span>-beam are obtained through a non-conventional method by proposing a dielectric charging technique and scanning <span class="hlt">electron</span> microscope based imaging. As distinct from the earlier developed <span class="hlt">sheet</span> beam sources, the generated <span class="hlt">sheet</span>-beam has been propagated more than 190 mm distance in a drift space region maintaining <span class="hlt">sheet</span> structure without assistance of any external magnetic field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22303433','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22303433"><span id="translatedtitle"><span class="hlt">Electron</span> distributions observed with Langmuir waves in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hwang, Junga; Rha, Kicheol; Seough, Jungjoon; Yoon, Peter H.</p> <p>2014-09-15</p> <p>The present paper investigates the Langmuir turbulence driven by counter-streaming <span class="hlt">electron</span> beams and its plausible association with observed features in the Earth's <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer region. A one-dimensional electrostatic particle-in-cell simulation code is employed in order to simulate broadband electrostatic waves with characteristic frequency in the vicinity of the <span class="hlt">electron</span> <span class="hlt">plasma</span> frequency ω/ω{sub pe}≃1.0. The present simulation confirms that the broadband electrostatic waves may indeed be generated by the counter-streaming <span class="hlt">electron</span> beams. It is also found that the observed feature associated with low energy <span class="hlt">electrons</span>, namely quasi-symmetric velocity space plateaus, are replicated according to the present simulation. However, the present investigation only partially succeeds in generating the suprathermal tails such that the origin of observed quasi power-law energetic population formation remains outstanding.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5597563','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5597563"><span id="translatedtitle">The relationship between diffuse auroral and <span class="hlt">plasma</span> <span class="hlt">sheet</span> <span class="hlt">electron</span> distributions near local midnight</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Schumaker, T.L. ); Gussenhoven, M.S. ); Hardy, D.A.; Carovillano, R.L.</p> <p>1989-08-01</p> <p>A study of the relationship between diffuse auroral and <span class="hlt">plasma</span> <span class="hlt">sheet</span> <span class="hlt">electron</span> distributions in the energy range from 50 eV to 20 keV in the midnight region was conducted using data from the P78-1 and SCATHA satellites. From 1 1/2 years of data, 14 events were found where the polar-orbiting P78-1 satellite and the near-geosynchronous SCATHA satellite were approximately on the same magnetic field line simultaneously, with SCATHA in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and P78-1 in the diffuse auroral region. For all cases the spectra from the two satellites are in good quantitative agreement. For 13 of the 14 events the pitch angle distribution measured at P78-1 was isotropic for angles mapping into the loss cone at the SCATHA orbit. For one event the P78-1 <span class="hlt">electron</span> flux decreased with pitch angle toward the field line direction. At SCATHA the distributions outside the loss cone were most commonly butterfly or pancake, although distributions peaked toward the field line were sometimes observed at energies below 1 keV. <span class="hlt">Electron</span> distributions, as measured where there is isotropy within the loss cone but anisotropy outside the loss cone, are inconsistent with current theories for the scattering of cone for the distribution measured at SCATHA, the <span class="hlt">electron</span> precipitation lifetimes were calculated for the 14 events. Because the distributions are anisotropic at pitch angles away from the loss cone, the calculated lifetimes significantly exceed the lifetimes in the limit when the flu is isotropic at all pitch angles. The computed precipitation lifetimes are found to be weakly dependent on magnetic activity. The average lifetimes exceed those for the case of isotropy at all pitch angles by a factor between 2 and 3 for {ital Kp}{le}2 and approximately 1.5 for {ital Kp}{gt}2. {copyright} American Geophysical Union 1989</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/7174737','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/7174737"><span id="translatedtitle">Observations of correlated broadband electrostatic noise and <span class="hlt">electron</span>-cyclotron emissions in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. Technical report</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Roeder, J.L.; Angelopoulos, V.; Baumjohann, W.; Anderson, R.R.</p> <p>1991-11-15</p> <p>Electric field wave observations in the central <span class="hlt">plasma</span> <span class="hlt">sheet</span> of the earth's magnetosphere show the correlated occurrence of broadband electrostatic noise and electrostatic <span class="hlt">electron</span> cyclotron harmonic emissions. A model is proposed in which the broadband emissions are <span class="hlt">electron</span> acoustic waves generated by an observed low energy <span class="hlt">electron</span> beam, and the cyclotron emissions are generated by the hot <span class="hlt">electron</span> loss cone instability. The high degree of correlation between the two emissions is provided in the model by the presence of the cold <span class="hlt">electron</span> beam population, which allows both of the <span class="hlt">plasma</span> instabilities to grow.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRA..119.8902D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRA..119.8902D"><span id="translatedtitle">Energetic <span class="hlt">electron</span> bursts in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and their relation with BBFs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Duan, A. Y.; Cao, J. B.; Dunlop, M.; Wang, Z. Q.</p> <p>2014-11-01</p> <p>We studied energetic <span class="hlt">electron</span> bursts (EEBs) (40-250 keV) in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> (PS) and their relation to bursty bulk flows (BBFs) using the data recorded by Cluster from 2001 to 2009. The EEBs in the PS can be classified into four types. Three types of EEBs are dispersionless, including EEBs accompanied with BBFs (V > 250 km/s) but without dipolarization front (DF); EEBs accompanied with both dipolarization front (DF) and BBF; and EEBs accompanied with DF and fast flow with V < 250 km/s. One type of EEB, i.e., EEBs not accompanied with BBFs and DFs, is dispersed. The energetic <span class="hlt">electrons</span> (40-130 keV) can be easily transported earthward by BBFs due to the strong dawn-dusk electric field embedded in BBFs. The DFs in BBFs can produce energetic <span class="hlt">electrons</span> (40 to 250 keV). For the EEBs with DF and BBFs, the superposed epoch analyses show that the increase of energetic <span class="hlt">electron</span> flux has two phases: gradual increase phase before DF and rapid increase phase concurrent with DF. In the PS around x = -18 RE, 60%-70% of EEBs are accompanied with BBFs, indicating that although hitherto there have been various acceleration mechanisms of energetic <span class="hlt">electrons</span>, most of the energetic <span class="hlt">electrons</span> in the PS are related with magnetic reconnection, and they are produced either directly by magnetic reconnection or indirectly by the DFs within BBFs. In the BBF's braking region of -12 RE < x < -10 RE, 20% of EEBs are accompanied with BBFs. The corresponding ratio between EEBs and BBFs shows a dawn-dusk asymmetry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19810047809&hterms=three+layers+Earth&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dthree%2Blayers%2BEarth','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19810047809&hterms=three+layers+Earth&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dthree%2Blayers%2BEarth"><span id="translatedtitle">Energetic ion and <span class="hlt">electron</span> observations of the geomagnetic <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer - Three-dimensional results from ISEE 1</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Spjeldvik, W. N.; Fritz, T. A.</p> <p>1981-01-01</p> <p>A description of energetic ion and <span class="hlt">electron</span> behavior in the geomagnetic <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer is presented based on observations made by the medium-energy particle experiment on board ISEE 1. Three-dimensional observations of ions of energies 24-2081 keV and <span class="hlt">electrons</span> of energies 22.5-1200 keV were obtained by the NOAA/WAPS instrument near the center of the magnetotail at a distance of approximately 15 earth radii. Large-scale motions of <span class="hlt">plasma</span> <span class="hlt">sheet</span> energetic particles are observed as an apparent result of a series of magnetospheric disturbances (substorms), which are characterized by substantial contractions and expansions. Ion flow velocity in a distinct boundary layer in energetic ions has been found to be in the earthward direction in each of the five ISEE 1 boundary crossings. Boundary layer motion during one of these crossings is interpreted as large-amplitude boundary waves with periodicities of a few minutes superimposed on the general <span class="hlt">plasma</span> <span class="hlt">sheet</span> behavior associated with the substorm process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhDT.......138S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhDT.......138S"><span id="translatedtitle"><span class="hlt">Sheet</span> <span class="hlt">electron</span> beam tester</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Spear, Alexander Grenbeaux</p> <p></p> <p>The DARPA HiFIVE project uses a pulsed <span class="hlt">electron</span> <span class="hlt">sheet</span> beam gun to power a traveling wave tube amplifier operating at 220 GHz. Presented is a method for characterizing the high current density 0.1 mm by 1 mm <span class="hlt">sheet</span> <span class="hlt">electron</span> beam. A tungsten tipped probe was scanned through the cross section of the <span class="hlt">sheet</span> <span class="hlt">electron</span> beam inside of a vacuum vessel. The probe was controlled with sub-micron precision using stepper motors and LabView computer control while boxcar averaging hardware sampled the pulsed beam. Matlab algorithms were used to interpret the data, calculate beam dimensions and current density, and create 2-dimensional cross section images. Full characterization of two separate HiFIVE <span class="hlt">sheet</span> <span class="hlt">electron</span> guns was accomplished and is also presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19880052817&hterms=Beans&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DBeans','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19880052817&hterms=Beans&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DBeans"><span id="translatedtitle">Simulation of electrostatic turbulence in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer with <span class="hlt">electron</span> currents and bean-shaped ion beams</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nishikawa, K.-I.; Frank, L. A.; Huang, C. Y.</p> <p>1988-01-01</p> <p><span class="hlt">Plasma</span> data from ISEE-1 show the presence of <span class="hlt">electron</span> currents as well as energetic ion beams in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer. Broadband electrostatic noise and low-frequency electromagnetic bursts are detected in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer, especially in the presence of strong ion flows, currents, and steep spacial gradients in the fluxes of few-keV <span class="hlt">electrons</span> and ions. Particle simulations have been performed to investigate electrostatic turbulence driven by a cold <span class="hlt">electron</span> beam and/or ion beams with a bean-shaped velocity distribution. The simulation results show that the counterstreaming ion beams as well as the counterstreaming of the cold <span class="hlt">electron</span> beam and the ion beam excite ion acoustic waves with a given Doppler-shifted real frequency. However, the effect of the bean-shaped ion velocity distributions reduces the growth rates of ion acoustic instability. The simulation results also show that the slowing down of the ion bean is larger at the larger perpendicular velocity. The wave spectra of the electric fields at some points of the simulations show turbulence generated by growing waves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PhPl...15b2504B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PhPl...15b2504B"><span id="translatedtitle">Study of magnetic configuration effects on <span class="hlt">plasma</span> boundary and measurement of edge <span class="hlt">electron</span> density in the spherical tokamak compact <span class="hlt">plasma</span> wall interaction experimental device using Li <span class="hlt">sheet</span> beam</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bhattacharyay, R.; Zushi, H.; Morisaki, T.; Inada, Y.; Kikukawa, T.; Watanabe, S.; Sasaki, K.; Ryoukai, T.; Hasegawa, M.; Hanada, K.; Sato, K. N.; Nakamura, K.; Sakamoto, M.; Idei, H.; Yoshinaga, T.; Kawasaki, S.; Nakashima, H.; Higashijima, A.</p> <p>2008-02-01</p> <p>Two-dimensional lithium beam imaging technique has been applied in the spherical tokamak CPD (compact <span class="hlt">plasma</span> wall interaction experimental device) to study the effects of magnetic field configurations on rf <span class="hlt">plasma</span> boundary in the absence of any <span class="hlt">plasma</span> current, and also for the measurement of a two-dimensional edge <span class="hlt">electron</span> density profile. With the present working condition of the diagnostics, the minimum measured <span class="hlt">electron</span> density can be 1.01016m-3; this is considered to be the definition for the <span class="hlt">plasma</span> boundary. The performance of the lithium <span class="hlt">sheet</span> beam is absolutely calibrated using a quartz crystal monitor. Experimental results reveal that magnetic field configuration, either mirror or so-called null, critically affects the rf <span class="hlt">plasma</span> boundary. A sharp lower boundary is found to exist in magnetic null configuration, which is quite different from that in the weak mirror configuration. Theoretical calculations of particle drift orbit and magnetic connection length (wall-to-wall) suggest that only mirror trapped particles are confined within a region where the magnetic connection length is 4.0m or more. A two-dimensional edge <span class="hlt">electron</span> density profile is obtained from the observed LiI intensity profile. Overdense <span class="hlt">plasma</span> formation is discussed from the viewpoint of mode conversion of rf wave into <span class="hlt">electron</span> Bernstein wave and its dependence on the <span class="hlt">electron</span> density profile.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19770048535&hterms=anisotropy+earth&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Danisotropy%2Bearth','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19770048535&hterms=anisotropy+earth&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Danisotropy%2Bearth"><span id="translatedtitle">Observations of energetic <span class="hlt">electrons</span> /E no less than about 200 keV/ in the earth's magnetotail - <span class="hlt">Plasma</span> <span class="hlt">sheet</span> and fireball observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Baker, D. N.; Stone, E. C.</p> <p>1977-01-01</p> <p>An earlier paper by the authors (1976) has reported on energetic <span class="hlt">electron</span> anisotropies observed in conjunction with the acceleration regions identified by Frank et al., (1976). The present paper gives more detailed analyses of observations in the distant <span class="hlt">plasma</span> <span class="hlt">sheet</span>, including specific features of intensities, energy spectra, and pitch angle distributions of the very energetic <span class="hlt">electrons</span> associated with intense <span class="hlt">plasma</span> particle events, with energies ranging between 50 eV and 45 keV, detected with an <span class="hlt">electron</span>/isotope spectrometer aboard the earth-orbiting spacecraft Imp 8. Two domains are considered: the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and the regions near and within the localized magnetotail acceleration regions known as the fireball regions. The instrumentation used offered a number of observational advantages over many previous studies, including inherently low background, large geometric factors, excellent species identification, good angular distribution measurement capability, and availability of high resolution of differential intensities.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li class="active"><span>1</span></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_1 --> <div id="page_2" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li class="active"><span>2</span></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="21"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMSM42B..07G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMSM42B..07G"><span id="translatedtitle">Effect of an MLT dependent <span class="hlt">electron</span> loss rate on the inner magnetosphere electrodynamics and <span class="hlt">plasma</span> <span class="hlt">sheet</span> penetration to the ring current region</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gkioulidou, M.; Wang, C.; Wing, S.; Lyons, L. R.; Wolf, R. A.; Hsu, T.</p> <p>2012-12-01</p> <p>Transport of <span class="hlt">plasma</span> <span class="hlt">sheet</span> particles into the ring current region is strongly affected by the penetrating convection electric field, which is the result of the large-scale magnetosphere-ionosphere (M-I) electromagnetic coupling. One of the main factors controlling this coupling is the ionospheric conductance. As <span class="hlt">plasma</span> <span class="hlt">sheet</span> <span class="hlt">electrons</span> drift earthward, they get scattered into the loss cone due to wave-particle interactions and precipitate to the ionosphere, producing auroral conductance. Realistic <span class="hlt">electron</span> loss is thus important for modeling the (M-I) coupling and penetration of <span class="hlt">plasma</span> <span class="hlt">sheet</span> into the inner magnetosphere. To evaluate the significance of <span class="hlt">electron</span> loss rate, we used the Rice Convection Model (RCM) coupled with a force-balanced magnetic field to simulate <span class="hlt">plasma</span> <span class="hlt">sheet</span> transport under different <span class="hlt">electron</span> loss rates and under self-consistent electric and magnetic field. The <span class="hlt">plasma</span> <span class="hlt">sheet</span> ion and <span class="hlt">electron</span> sources for the simulations are based on the Geotail observations. Two major rates are used: different portions of i) strong pitch-angle diffusion everywhere <span class="hlt">electron</span> loss rate (strong rate) and ii) a more realistic loss rate with its MLT dependence determined by wave activity (MLT rate). We found that the dawn-dusk asymmetry in the precipitating <span class="hlt">electron</span> energy flux under the MLT rate, with much higher energy flux at dawn than at dusk, agrees better with statistical DMSP observations. <span class="hlt">Electrons</span> trapped inside L ~ 8 RE can remain there for many hours under the MLT rate, while those under the strong rate get lost within minutes. Compared with the strong rate, the remaining <span class="hlt">electrons</span> under the MLT rate cause higher conductance at lower latitudes, allowing for less efficient electric field shielding to convection enhancement, thus further earthward penetration of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> into the inner magnetosphere. Therefore, our simulation results indicate that the <span class="hlt">electron</span> loss rate can significantly affect the electrodynamics of the ring current region. Development of a more realistic <span class="hlt">electron</span> loss rate model for the inner magnetosphere is thus much needed and will become feasible with new observations from the upcoming RBSP mission.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JGRA..116.8201J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JGRA..116.8201J"><span id="translatedtitle">Statistics of <span class="hlt">plasma</span> <span class="hlt">sheet</span> convection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Juusola, L.; Østgaard, N.; Tanskanen, E.</p> <p>2011-08-01</p> <p>Determining the characteristics of <span class="hlt">plasma</span> <span class="hlt">sheet</span> convection and their response to changes in various solar wind parameters is important for understanding the energy and mass transport, as well as disturbance propagation, through geospace. We use 15 years of data obtained by Geotail, Cluster, and THEMIS to study statistically the characteristics of <span class="hlt">plasma</span> <span class="hlt">sheet</span> flows and the effect of the interplanetary magnetic field (IMF) on the convection. We find that <span class="hlt">plasma</span> <span class="hlt">sheet</span> convection is dominated by slow speed (<100 km/s) flows that circulate around Earth on both sides toward the dayside. With increasing flow speed the sunward component of the flow velocity becomes more pronounced such that flows with V > 500 km/s are directed almost purely sunward. Both IMF By and IMF Bz are observed to penetrate the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. During southward IMF conditions, a channel of increased Bz is created in the nightside around the aberrated midnight axis. We suggest that the channel is caused by dipolarization and magnetic flux pileup related to fast flows. The nightside region of highest mean flow speed is located more duskward during dawnward IMF conditions than during duskward IMF conditions. For <span class="hlt">plasma</span> <span class="hlt">sheet</span> flows with speeds higher than 100 km/s, we find that the orientation of IMF (clock angle) controls the speeds, while the magnitude of the solar wind electric field plays a minor role. The increasing speed indicates that energy transfer per unit length of the nightside X line increases as IMF turns southward.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/820113','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/820113"><span id="translatedtitle">MHD Ballooning Instability in the <span class="hlt">Plasma</span> <span class="hlt">Sheet</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>C.Z. Cheng; S. Zaharia</p> <p>2003-10-20</p> <p>Based on the ideal-MHD model the stability of ballooning modes is investigated by employing realistic 3D magnetospheric equilibria, in particular for the substorm growth phase. Previous MHD ballooning stability calculations making use of approximations on the <span class="hlt">plasma</span> compressibility can give rise to erroneous conclusions. Our results show that without making approximations on the <span class="hlt">plasma</span> compressibility the MHD ballooning modes are unstable for the entire <span class="hlt">plasma</span> <span class="hlt">sheet</span> where beta (sub)eq is greater than or equal to 1, and the most unstable modes are located in the strong cross-tail current <span class="hlt">sheet</span> region in the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span>, which maps to the initial brightening location of the breakup arc in the ionosphere. However, the MHD beq threshold is too low in comparison with observations by AMPTE/CCE at X = -(8 - 9)R(sub)E, which show that a low-frequency instability is excited only when beq increases over 50. The difficulty is mitigated by considering the kinetic effects of ion gyrorad ii and trapped <span class="hlt">electron</span> dynamics, which can greatly increase the stabilizing effects of field line tension and thus enhance the beta(sub)eq threshold [Cheng and Lui, 1998]. The consequence is to reduce the equatorial region of the unstable ballooning modes to the strong cross-tail current <span class="hlt">sheet</span> region where the free energy associated with the <span class="hlt">plasma</span> pressure gradient and magnetic field curvature is maximum.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005GeoRL..3224103L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005GeoRL..3224103L"><span id="translatedtitle">Duskside auroral undulations observed by IMAGE and their possible association with large-scale structures on the inner edge of the <span class="hlt">electron</span> <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lewis, W. S.; Burch, J. L.; Goldstein, J.; Horton, W.; Perez, J. C.; Frey, H. U.; Anderson, P. C.</p> <p>2005-12-01</p> <p>On February 6, 2002 large-scale undulations along the equatorward edge of the afternoon/dusk auroral oval were observed with the IMAGE FUV/Wideband Imaging Camera (WIC) during the late expansion/recovery phase of a substorm. The undulations are similar to others previously reported, but occur at higher than usual latitudes and map to the outer duskside magnetosphere, 1 to 2 RE beyond a plasmaspheric drainage plume. The mapping suggests that the undulations result from large-scale fluctuations on the inner edge of the <span class="hlt">electron</span> <span class="hlt">plasma</span> <span class="hlt">sheet</span>. 2.5-D simulations using representative <span class="hlt">plasma</span> parameters for this region indicate that such large-scale coherent structures can be created by a kinetic drift wave driven by the ion pressure gradient in the destabilizing curvature and grad B drift of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> ions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006JGRA..111.5206O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006JGRA..111.5206O"><span id="translatedtitle"><span class="hlt">Plasma</span> <span class="hlt">sheet</span> expansion: Statistical characteristics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ohtani, S.; Mukai, T.</p> <p>2006-05-01</p> <p>The present study addresses the cause of <span class="hlt">plasma</span> <span class="hlt">sheet</span> expansion by statistically comparing the characteristics of lobe-to-<span class="hlt">plasma</span> <span class="hlt">sheet</span> (LB-to-PS) and PS-to-LB crossings observed by the Geotail satellite. Whereas the flapping motion of the magnetotail causes both types of crossing, the PS expansion (thinning) can be associated only with the LB-to-PS (PS-to-LB) crossing. Thus any systematic difference between the two types of crossing should reflect the difference between the PS expansion and thinning. Geotail observed more LB-to-PS crossings (744 events) than PS-to-LB crossings (640 events), and the preferred occurrence of the LB-to-PS crossing is more manifest closer to the Earth. It is found that at the PS-to-LB crossing, the <span class="hlt">plasma</span> moves in the same direction as the boundary motion. At the LB-to-PS crossing, in contrast, the <span class="hlt">plasma</span> often moves in the opposite direction to the boundary motion, indicating that there is a finite electric field in the frame of the boundary motion associated with the PS expansion. The PS expansion is therefore considered to be a manifestation of magnetic reconnection. That is, the PS expands because new PS flux tubes are added onto the preexisting PS. In the course of the PS expansion, the total pressure decreases, which may be interpreted in terms of the replacement of the preexisting PS <span class="hlt">plasma</span> with new low-pressure <span class="hlt">plasma</span> originating from the tail lobe. The PS expansion is also characterized by relaxation (dipolarization) of the local magnetic field, which is inferred to be a direct consequence of reconnection. On the basis of recent reports of the lack of a one-to-one correspondence between reconnection and substorm onset, it is suggested that the PS expansion cannot be uniquely associated with a specific substorm phase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM51B2178L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM51B2178L"><span id="translatedtitle">The Effects of Non-adiabatic Processes on Near-Earth <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> <span class="hlt">Electrons</span> for Different Substorm-Related Magnetotail Conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liang, H.; Ashour-Abdalla, M.; Richard, R. L.; Schriver, D.; El-Alaoui, M.; Walker, R. J.</p> <p>2013-12-01</p> <p>We investigate the spatial evolution of energetic <span class="hlt">electron</span> distribution functions in the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> associated with earthward propagating dipolarization fronts by using in situ observations as well as magnetohydrodynamic (MHD) and large scale kinetic (LSK) simulations. We have investigated two substorms, one on February 15, 2008 and the other on August 15, 2001. The February 15 event was observed by one of the THEMIS spacecraft at X_{GSM} -10RE, while the August 15 event was observed by Cluster at X -18RE. Both the MHD and LSK simulation results are compared to these spacecraft observations. Earthward propagating dipolarization fronts are found in both the observations and the MHD simulations, which exhibit very different magnetotail configurations, with contrasting flows, magnetic reconnection configuration, and <span class="hlt">plasma</span> <span class="hlt">sheet</span> structure. <span class="hlt">Electron</span> LSK simulations were performed by using the time-varying magnetic and electric fields from the global MHD simulations. For the February 15, 2008 event, the <span class="hlt">electrons</span> were launched near X = -20 RE with a thermal energy of 1 keV and for August 15, 2001 event, they were launched at 4 keV near X = -22 RE. These <span class="hlt">electrons</span> undergo both non-adiabatic acceleration near the magnetotail reconnection region and adiabatic acceleration as they propagate earthward from the launch region. We compute the <span class="hlt">electron</span> distribution functions parallel and perpendicular to the magnetic field at different locations between X = -18 RE and X = -10 RE in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. We find that for the February 15, 2008 event, reconnection is localized with a narrow region of high-speed flows ( 300 km/s). For this event the distribution functions show mainly f(v_perp) > f(v_par) ("par" and "perp" correspond to parallel and perpendicular to magnetic field). On August 15, 2001, there is a neutral line extending across the tail with relatively low-speed flows ( 100 km/s). For this event the distribution functions show mainly f(v_par) > f(v_perp). The different magnetotail configurations result in different amounts of non-adiabatic acceleration, leading to different <span class="hlt">electron</span> distribution functions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JGRA..115.8217B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JGRA..115.8217B"><span id="translatedtitle">Magnetic field at geosynchronous orbit during high-speed stream-driven storms: Connections to the solar wind, the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, and the outer <span class="hlt">electron</span> radiation belt</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Borovsky, Joseph E.; Denton, Michael H.</p> <p>2010-08-01</p> <p>Superposed-epoch analysis is performed on magnetic field measurements from five GOES spacecraft in geosynchronous orbit during 63 high-speed stream-driven storms in 1995-2005. The field strength and the field stretching angle are examined as functions of time and local time, and these quantities are compared with the properties of the solar wind, the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, and the outer <span class="hlt">electron</span> radiation belt. Compression of the dayside magnetosphere coincides with an increased solar wind ram pressure commencing before the arrival of the corotating interaction region (CIR). Stretching of the nightside magnetosphere occurs in two phases: a strong-stretching phase early in the storm followed by a modest-stretching phase lasting for days. The strong-stretching phase coincides with the occurrence of the superdense <span class="hlt">plasma</span> <span class="hlt">sheet</span>, implying that ion pressure causes the strong stretching. This nightside strong-stretching perturbation corresponds to a ˜25% contribution to Dst*. The relativistic <span class="hlt">electron</span> flux at geosynchronous orbit has a dropout recovery temporal profile that matches the strong-stretching temporal profile; however, the number density dropout and recovery of the <span class="hlt">electron</span> radiation belt has a profile that leads the stretching profile. A comparison of geosynchronous field strengths and magnetopause field strengths indicates that magnetopause shadowing plays a role in the radiation belt dropout. Temporal fluctuations of the geosynchronous magnetic field are examined via 1 min changes of the GOES magnetic field vectors. Fluctuation amplitudes increase at all local times at storm onset and then slowly decay during the storms. The amplitude is linearly related to the Kp, PCI, and MBI indices, except during the strong-stretching phase of the storms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060009466&hterms=multifractal+cross-&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmultifractal%2Bcross-','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060009466&hterms=multifractal+cross-&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmultifractal%2Bcross-"><span id="translatedtitle"><span class="hlt">Plasma</span> <span class="hlt">sheet</span> turbulence observed by Cluster II</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Weygand, James M.; Kivelson, M. G.; Khurana, K. K.; Schwarzl, H. K.; Thompson, S. M.; McPherron, R. L.; Balogh, A.; Kistler, L. M.; Goldstein, M. L.; Borovsky, J.</p> <p>2005-01-01</p> <p>Cluster fluxgate magnetometer (FGM) and ion spectrometer (CIS) data are employed to analyze magnetic field fluctuations within the <span class="hlt">plasma</span> <span class="hlt">sheet</span> during passages through the magnetotail region in the summers of 2001 and 2002 and, in particular, to look for characteristics of magnetohydrodynamic (MHD) turbulence. Power spectral indices determined from power spectral density functions are on average larger than Kolmogorov's theoretical value for fluid turbulence as well as Kraichnan's theoretical value for MHD <span class="hlt">plasma</span> turbulence. Probability distribution functions of the magnetic fluctuations show a scaling law over a large range of temporal scales with non-Gaussian distributions at small dissipative scales and inertial scales and more Gaussian distribution at large driving scales. Furthermore, a multifractal analysis of the magnetic field components shows scaling behavior in the inertial range of the fluctuations from about 20 s to 13 min for moments through the fifth order. Both the scaling behavior of the probability distribution functions and the multifractal structure function suggest that intermittent turbulence is present within the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. The unique multispacecraft aspect and fortuitous spacecraft spacing allow us to examine the turbulent eddy scale sizes. Dynamic autocorrelation and cross correlation analysis of the magnetic field components allow us to determine that eddy scale sizes fit within the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. These results suggest that magnetic field turbulence is occurring within the <span class="hlt">plasma</span> <span class="hlt">sheet</span> resulting in turbulent energy dissipation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMSH33C..05L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMSH33C..05L"><span id="translatedtitle">Heliospheric current <span class="hlt">sheet</span> and <span class="hlt">plasma</span> <span class="hlt">sheet</span> crossings associated with heatflux dropouts: A statistical survey using STEREO observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Y.; Galvin, A. B.; Popecki, M.; Simunac, K.; Kistler, L. M.; Farrugia, C. J.; Moebius, E.; Jian, L.; Opitz, A.; Luhmann, J. G.</p> <p>2010-12-01</p> <p>We investigate the heliospheric current <span class="hlt">sheet</span> (HCS) crossing events and the related heliospheric <span class="hlt">plasma</span> <span class="hlt">sheet</span> (HPS) on both STEREO spacecraft from Mar, 1, 2008 to Dec, 31, 2008. Observed <span class="hlt">plasma</span> <span class="hlt">sheets</span> are categorized into two types based on their relative position to the current <span class="hlt">sheets</span>. Type I <span class="hlt">plasma</span> <span class="hlt">sheets</span> straddle the current <span class="hlt">sheets</span>, and type II <span class="hlt">plasma</span> <span class="hlt">sheets</span> are located on one side of the current <span class="hlt">sheets</span>. The <span class="hlt">electron</span> heat flux dropouts (HFD) are also documented for each type of <span class="hlt">plasma</span> <span class="hlt">sheets</span>. Initially, the investigation was limited to 39 ideal HCS crossings. Among the initial 39 HCS crossings in our study, 4 have no HPS, 21 have a type I HPS, and 13 a Type II HPS. Most of the Type II HCSs don’t show a HFD, but a large portion of type I HPSs show a HFD. Later, the study is generalized to all HCS events for which we can determine the actual time and properties of the HPS. This conclusion still holds when all the identifiable HPS are included in the study. Schematic plots summing the different magnetic field configurations are presented, and the potential origin of <span class="hlt">plasmas</span> forming the two types of HPS is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850029387&hterms=McCarthy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DMcCarthy%252C%2BR','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850029387&hterms=McCarthy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DMcCarthy%252C%2BR"><span id="translatedtitle">Particle and field characteristics of the high-latitude <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Parks, G. K.; Mccarthy, M.; Fitzenreiter, R. J.; Ogilvie, K. W.; Etcheto, J.; Anderson, K. A.; Lin, R. P.; Anderson, R. R.; Eastman, T. E.; Frank, L. A.</p> <p>1984-01-01</p> <p>Particle and field data obtained by eight ISEE spacecraft experiments are used to define more precisely the characteristics of the high-latitude boundary region of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. A region immediately adjacent to the high-latitude <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary has particle and field characteristics distinctly different from those observed in the lobe and deeper in the central <span class="hlt">plasma</span> <span class="hlt">sheet</span>. <span class="hlt">Electrons</span> over a broad energy interval are 'field-aligned' and bidirectional, whereas in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> the distributions are more isotropic. The region supports intense ion flows, large-amplitude electric fields, and enhanced broad-band electrostatic noise.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19840051849&hterms=Plasma+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DPlasma%2Benergy','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19840051849&hterms=Plasma+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DPlasma%2Benergy"><span id="translatedtitle">Relationship of dusk sector radial electric field to energy dispersion at the inner edge of the <span class="hlt">electron</span> <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Horwitz, J. L.</p> <p>1984-01-01</p> <p>It is shown that, by assuming that the magnetospheric particle boundaries are the result of steady state convection, the <span class="hlt">electron</span> boundaries in the dusk sector are essentially sensitive to the local, not the global, electric field configuration. A simple, direct relationship is obtained between the dusk sector radial electric field and the inner edge of <span class="hlt">electron</span> boundaries at various energies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/doepatents/biblio/874183','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/doepatents/biblio/874183"><span id="translatedtitle">Thermomechanical processing of <span class="hlt">plasma</span> sprayed intermetallic <span class="hlt">sheets</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Hajaligol, Mohammad R. (Midlothian, VA); Scorey, Clive (Cheshire, CT); Sikka, Vinod K. (Oak Ridge, TN); Deevi, Seetharama C. (Midlothian, VA); Fleischhauer, Grier (Midlothian, VA); Lilly, Jr., A. Clifton (Chesterfield, VA); German, Randall M. (State College, PA)</p> <p>2001-01-01</p> <p>A powder metallurgical process of preparing a <span class="hlt">sheet</span> from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The <span class="hlt">sheet</span> can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.0.05% Zr .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Ni, .ltoreq.0.75% C, .ltoreq.0.1% B, .ltoreq.1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, and/or .ltoreq.3% Cu. The process includes forming a non-densified metal <span class="hlt">sheet</span> by consolidating a powder having an intermetallic alloy composition such as by roll compaction, tape casting or <span class="hlt">plasma</span> spraying, forming a cold rolled <span class="hlt">sheet</span> by cold rolling the non-densified metal <span class="hlt">sheet</span> so as to increase the density and reduce the thickness thereof and annealing the cold rolled <span class="hlt">sheet</span>. The powder can be a water, polymer or gas atomized powder which is subjecting to sieving and/or blending with a binder prior to the consolidation step. After the consolidation step, the <span class="hlt">sheet</span> can be partially sintered. The cold rolling and/or annealing steps can be repeated to achieve the desired <span class="hlt">sheet</span> thickness and properties. The annealing can be carried out in a vacuum furnace with a vacuum or inert atmosphere. During final annealing, the cold rolled <span class="hlt">sheet</span> recrystallizes to an average grain size of about 10 to 30 .mu.m. Final stress relief annealing can be carried out in the B2 phase temperature range.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006cosp...36..199L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006cosp...36..199L"><span id="translatedtitle">Trajectories of <span class="hlt">Electrons</span> and Protons in the Reconnecting Current <span class="hlt">Sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lin, J.</p> <p></p> <p>In the framework of the catastrophe model of solar eruptions a current <span class="hlt">sheet</span> forms separating two magnetic fields of opposite polarity as the magnetic structure loses the equilibrium and stretches the closed magnetic field lines severely Magnetic fields and <span class="hlt">plasma</span> near the <span class="hlt">sheet</span> are driven toward the current <span class="hlt">sheet</span> and magnetic reconnection converts the magnetic energy into the other types of energy In this process an electric field in the current <span class="hlt">sheet</span> is induced by the reconnection inflow Both theories and observations show that this electric field could be of a few V cm at maximum The electric field of such strength is able to accelerate any charged particles especially <span class="hlt">electrons</span> and protons This work investigates motions of <span class="hlt">electrons</span> and protons in the 3D reconnecting current <span class="hlt">sheets</span> via the test particle approach The collisionless environment in the current <span class="hlt">sheet</span> allows us to ignore collisions among particles Our results indicate that motions of individual particles are confined within certain places We find that these particles either gather together around the X-point along the z -axis or shoot out of the current <span class="hlt">sheet</span> along the separatrices and that they may leave the current <span class="hlt">sheet</span> along any separatrix So their motions do not yield extra electric current</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFMSM72A0601T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFMSM72A0601T"><span id="translatedtitle">Electric Field Measurements at the Boundary of the Near-Earth <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> as Measured by the <span class="hlt">Electron</span> Drift Instrument (EDI) and the Electric Field and Waves Instrument (EFW ) on the CLUSTER Spacecraft</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Torbert, R. B.; Paschmann, G.; Quinn, J.; Kistler, L.; Mouikis, C.; Puhl-Quinn, P.; Georgescu, E.; Eriksson, A.; Lindqvist, P.; Glassmeier, K.</p> <p>2002-12-01</p> <p>The boundary of the night-time <span class="hlt">plasma</span> <span class="hlt">sheet</span> connects both to the reconnection regions in the magnetotail and to the poleward auroral region near earth. In active times, fields and particle populations in this boundary near earth often show rapid transport of energy toward the ionosphere. On CLUSTER, three dimensional electric fields, including the component parallel to B, can be measured by combining the information from the double-probe (EFW, measuring potential differences in the spin plane), and those of the <span class="hlt">Electron</span> Drift Instrument (EDI, measuring the perpendicular drift velocity of <span class="hlt">electrons</span>). We will show combined data from the night-time <span class="hlt">plasma</span> <span class="hlt">sheet</span> where large electric fields are sometimes observed near the boundaries and particle populations make rapid changes. These fields show a complex spatial and temporal structure that appears to be neither constant in time nor space. At times, the Alfven waves observed on this boundary indicate that a dense ( order 1/cc ) layer of ions, predominantly oxygen, lies outside the <span class="hlt">plasma</span> <span class="hlt">sheet</span> in the otherwise rarified lobe <span class="hlt">plasma</span>. As these ions are not seen by the composition analyzer on CLUSTER, CODIF, they are apparently very cold.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SSRv..188..311P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SSRv..188..311P"><span id="translatedtitle">Current <span class="hlt">Sheets</span> in the Earth Magnetotail: <span class="hlt">Plasma</span> and Magnetic Field Structure with Cluster Project Observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Petrukovich, Anatoli; Artemyev, Anton; Vasko, Ivan; Nakamura, Rumi; Zelenyi, Lev</p> <p>2015-05-01</p> <p>Thin current <span class="hlt">sheets</span> having kinetic scales are an important <span class="hlt">plasma</span> structure, where the magnetic energy dissipation and charged particle acceleration are the most effective. It is believed that such current <span class="hlt">sheets</span> are self-consistently formed by the specific nonadiabatic dynamics of charged particles and play a critical role in many space <span class="hlt">plasma</span> and astrophysical objects. Current <span class="hlt">sheets</span> in the near-Earth <span class="hlt">plasma</span> environment, e.g., the magnetotail current <span class="hlt">sheet</span>, are readily available for in-situ investigations. The dedicated multi-spacecraft Cluster mission have revealed basic properties of this current <span class="hlt">sheet</span>, which are presented in this review: typical spatial profiles of magnetic field and current density, distributions of <span class="hlt">plasma</span> temperature and density, role of heavy ions and <span class="hlt">electron</span> currents, etc. Being important for the Earth magnetosphere physics, the new knowledge also could provide the basis for advancement in general <span class="hlt">plasma</span> physics as well as in <span class="hlt">plasma</span> astrophysics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhPl...22l3517S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhPl...22l3517S"><span id="translatedtitle">Theoretical modeling of the <span class="hlt">plasma</span>-assisted catalytic growth and field emission properties of graphene <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sharma, Suresh C.; Gupta, Neha</p> <p>2015-12-01</p> <p>A theoretical modeling for the catalyst-assisted growth of graphene <span class="hlt">sheet</span> in the presence of <span class="hlt">plasma</span> has been investigated. It is observed that the <span class="hlt">plasma</span> parameters can strongly affect the growth and field emission properties of graphene <span class="hlt">sheet</span>. The model developed accounts for the charging rate of the graphene <span class="hlt">sheet</span>; number density of <span class="hlt">electrons</span>, ions, and neutral atoms; various elementary processes on the surface of the catalyst nanoparticle; surface diffusion and accretion of ions; and formation of carbon-clusters and large graphene islands. In our investigation, it is found that the thickness of the graphene <span class="hlt">sheet</span> decreases with the <span class="hlt">plasma</span> parameters, number density of hydrogen ions and RF power, and consequently, the field emission of <span class="hlt">electrons</span> from the graphene <span class="hlt">sheet</span> surface increases. The time evolution of the height of graphene <span class="hlt">sheet</span> with ion density and sticking coefficient of carbon species has also been examined. Some of our theoretical results are in compliance with the experimental observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.P42B..03S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.P42B..03S"><span id="translatedtitle">The State of the <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> and Atmosphere at Europa</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shemansky, D. E.; Yung, Y. L.; Liu, X.; Yoshii, J.; Hansen, C. J.; Hendrix, A.; Esposito, L. W.</p> <p>2014-12-01</p> <p>The Hall et al. (1995) report announcing the discovery of atomic oxygen FUV emission from Europa included a conclusion that the atmosphere was dominated by O2. Over the following 20 years publications referencing the atmosphere accepted this conclusion, and calculations of rates, particularly mass loading of the magnetosphere depended on a composition that was of order 90% O2. Analysis of the Europa emission spectrum in the present work, leads to the conclusion that the O I emission properties were misinterpreted. The interpretation of the source process depends on the ratio of the O I 1356 and 1304 A multiplet emissions (R(4:5) = (I(1356)/I(1304)). The value of R(4:5) never reaches the lower limit for <span class="hlt">electron</span> impact dissociation of O2 for any of the 7 recorded disk averaged measurements between 1994 and 2013. Analysis of the Cassini UVIS exposures show the 1304 A multiplet to be optically thick, and the emissions are modeled as direct <span class="hlt">electron</span> and solar photon excitation of O I. The result is a model atmosphere dominated by O I and O II, with neutral density a factor of 100 below the original O2 model. Other considerations show incompatibility with an O2 atmosphere. Deep exposures using the Cassini UVIS EUV spectrograph provide the state of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> at Europa. The ion species are identified as mainly outwardly diffused mass from the Io <span class="hlt">plasma</span> torus with a minor contribution from Europa. <span class="hlt">Plasma</span> time-constants are of the order of 200 days. Neutral species in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> are not measureable. The energy flux in the magnetosphere L-shells are mainly responsible for energy deposition maintaining the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. The energy content in the Io and Europa L-shells, as measured, is similar, but the mean radiative cooling rate in the Io <span class="hlt">plasma</span> torus at the time of the Cassini encounter was 565 femtoergs cm-3 s-1, compared to 7.3 at Europa, reflecting the difference between an active and inactive planetary satellite, particularly considering the fact that most of the radiation at the Europa <span class="hlt">plasma</span> <span class="hlt">sheet</span> is from ions that originated at the orbit of Io. The stochastic observational evidence in disk averaged Europa oxygen emission obtained over the 1994 to 2012 period shows no indication of transient events. A significant neutral transient injection in the Europa <span class="hlt">plasma</span> <span class="hlt">sheet</span> would take of order year time-scales to relax to steady state</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5384282','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5384282"><span id="translatedtitle">A pincer-shaped <span class="hlt">plasma</span> <span class="hlt">sheet</span> at Uranus</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hammond, C.M.; Walker, R.J.; Kivelson, M.G. )</p> <p>1990-09-01</p> <p>A model from Voigt et al. (1987) and an MHD simulation from Walker et al. (1989) both show that the curvature of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> at Uranus changes as the dipole tilt varies between 38{degree} and 22{degree}. The models suggest that one of the two partial traversals of the uranian <span class="hlt">plasma</span> <span class="hlt">sheet</span> made during the outbound trajectory of Voyager 2 can be explained as an entry into the highly curved <span class="hlt">plasma</span> <span class="hlt">sheet</span> that develops when Uranus is near the maximum dipole tilt value of 38{degree}; previously both partial traversals have been explained as anomalous. The spacecraft would have reversed its motion relative to the <span class="hlt">plasma</span> <span class="hlt">sheet</span> as the continued rotation diminished the dipole tilt and the retreating <span class="hlt">plasma</span> <span class="hlt">sheet</span> uncurled. As the dipole tilt approached its minimum value, spacecraft motion towards the neutral <span class="hlt">sheet</span> resumed and the traversal of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> was completed. Evidence from the PWS <span class="hlt">plasma</span> wave detector suggests that the spacecraft trajectory skimmed the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer for several hours prior to the partial immersion. The <span class="hlt">plasma</span> <span class="hlt">sheet</span> of the Voigt et al. model was not located near the spacecraft during this time interval. On the other hand, the MHD simulation reveals a <span class="hlt">plasma</span> <span class="hlt">sheet</span> that is more curved than in the Boigt et al. model; near maximum dipole tilt, the <span class="hlt">plasma</span> <span class="hlt">sheet</span> is pincer-shaped. The unusual geometry implies that Voyager 2 remained near the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer during the period suggested by the PWS data. Thus the simulation accounts easily for the first of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> encounters previously called anomalous. The second partial immersion remains anomalous, having previously been related to substorm activity, and thus is not discussed here. The stagnation distances of the earth and Uranus at the nose of the magnetopause were used to scale the Walker et al. (1989) simulation of the terrestrial magnetosphere to represent the uranian magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AnGeo..19.1669Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AnGeo..19.1669Q"><span id="translatedtitle">Cluster EDI convection measurements across the high-latitude <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary at midnight</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Quinn, J. M.; Paschmann, G.; Torbert, R. B.; Vaith, H.; McIlwain, C. E.; Haerendel, G.; Bauer, O.; Bauer, T. M.; Baumjohann, W.; Fillius, W.; Foerster, M.; Frey, S.; Georgescu, E.; Kerr, S. S.; Kletzing, C. A.; Matsui, H.; Puhl-Quinn, P.; Whipple, E. C.</p> <p>2001-10-01</p> <p>We examine two crossings of three Cluster satellites from the polar cap into the high-latitude <span class="hlt">plasma</span> <span class="hlt">sheet</span> at midnight local time, using data from the <span class="hlt">Electron</span> Drift Instrument (EDI). EDI measures the full <span class="hlt">electron</span> drift velocity in the plane perpendicular to the magnetic field for any field and drift directions. The context of the measured convection velocities is established by their relation to the intense enhancements in 1 keV <span class="hlt">electrons</span>, also measured by EDI, as the satellites move from the polar cap into the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary. In both cases presented here, the cross B convection in the polar cap is anti-sunward (toward the nightside <span class="hlt">plasma</span> <span class="hlt">sheet</span>) with a small duskward component. As the satellites enter the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary region, the dawn-dusk convective flow component reverses its sign, and the flow in the meridianal plane (toward the center of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>) drops substantially. The relatively stable convection in the polar cap becomes highly variable as the PSBL is encountered. The timing and sequence of the boundary crossings by the Cluster satellites are consistent with a relatively static structure on a time scale of the few minutes in satellite separations. In one of the two events, the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary has a spatially separate structure that is crossed by the satellites before entering the <span class="hlt">plasma</span> <span class="hlt">sheet</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JPSJ...80h4001S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JPSJ...80h4001S"><span id="translatedtitle">Kinetic Theory of Dawson <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sano, Mitsusada M.; Kitahara, Kazuo</p> <p>2011-08-01</p> <p>A kinetic theory of one-dimensional <span class="hlt">plasma</span> <span class="hlt">sheet</span> model (Dawson model) is developed. The Vlasov equation, the Landau equation, and the Balescu--Lenard equation corresponding to this model are derived. For the Vlasov equation, it is shown that the linearized Vlasov equation exhibits a typical behavior of <span class="hlt">plasmas</span> as in the three-dimensional space. The Landau collision term and the Balescu--Lenard collision term are identically zero. The fact of the vanishing collision term agrees with the behavior of generic one-dimesional systems. In an approximation that the system is in a thermal bath, the derived Landau equation and Balescu--Lenard equation are transformed into the Fokker--Planck equations. Some physical quantities such as thermal conductivity, relaxation rate, etc., are estimated. A discussion on physical meaning of these results, in particular, the zero collision terms, will be given.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li class="active"><span>2</span></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_2 --> <div id="page_3" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="41"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..DPPPP8134D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..DPPPP8134D"><span id="translatedtitle"><span class="hlt">Plasma</span> Relaxation Dynamics Moderated by Current <span class="hlt">Sheets</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dewar, Robert; Bhattacharjee, Amitava; Yoshida, Zensho</p> <p>2014-10-01</p> <p>Ideal magnetohydrodynamics (IMHD) is strongly constrained by an infinite number of microscopic constraints expressing mass, entropy and magnetic flux conservation in each infinitesimal fluid element, the latter preventing magnetic reconnection. By contrast, in the Taylor-relaxed equilibrium model all these constraints are relaxed save for global magnetic flux and helicity. A Lagrangian is presented that leads to a new variational formulation of magnetized fluid dynamics, relaxed MHD (RxMHD), all static solutions of which are Taylor equilibrium states. By postulating that some long-lived macroscopic current <span class="hlt">sheets</span> can act as barriers to relaxation, separating the <span class="hlt">plasma</span> into multiple relaxation regions, a further generalization, multi-relaxed MHD (MRxMHD), is developed. These concepts are illustrated using a simple two-region slab model similar to that proposed by Hahm and Kulsrud--the formation of an initial shielding current <span class="hlt">sheet</span> after perturbation by boundary rippling is calculated using MRxMHD and the final island state, after the current <span class="hlt">sheet</span> has relaxed through a reconnection sequence, is calculated using RxMHD. Australian Research Council Grant DP110102881.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFMSM21B..04T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFMSM21B..04T"><span id="translatedtitle">Three-Dimensional Electric Field Measurements at the <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> Boundary as measured by the <span class="hlt">Electron</span> Drift Instrument (EDI) and the Electric Field and Waves Instrument ( EFW ) on the CLUSTER Spacecraft</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Torbert, R. B.; Paschmann, G.; Quinn, J. M.; Baumjohann, W.; Mozer, F. S.; Kistler, L.; Mouikis, C.; Puhl-Quinn, P.; Andre, M.; Kletzing, C. A.; Lindqvist, P.</p> <p>2001-12-01</p> <p>On CLUSTER, three dimensional electric fields, including the component parallel to B, can be measured by combining the information from the double-probe (EFW) , and those of the <span class="hlt">Electron</span> Drift Instrument (EDI). EFW measures the potential difference between spherical probes spinning in a plane, and computes the two components of the field in that spin plane. EDI measures the drift-step vector, which is the displacement of <span class="hlt">electron</span> orbits after one gyro-period, and computes the two components of the field in the plane perpendicular to the magnetic field. Comparison of the field along the axis which is common to these two planes, shows very good agreement in many <span class="hlt">plasma</span> regions. We will show data from the night-time <span class="hlt">plasma</span> <span class="hlt">sheet</span> where large fields are sometimes observed near the boundaries and particle populations make rapid changes. These fields show a complex spatial and temporal structure that appears to be neither constant in time nor space.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22047555','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22047555"><span id="translatedtitle">Thin current <span class="hlt">sheets</span> in collisionless <span class="hlt">plasma</span>: Equilibrium structure, <span class="hlt">plasma</span> instabilities, and particle acceleration</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zelenyi, L. M.; Malova, H. V.; Artemyev, A. V.; Popov, V. Yu.; Petrukovich, A. A.</p> <p>2011-02-15</p> <p>The review is devoted to <span class="hlt">plasma</span> structures with an extremely small transverse size, namely, thin current <span class="hlt">sheets</span> that have been discovered and investigated by spacecraft observations in the Earth's magnetotail in the last few decades. The formation of current <span class="hlt">sheets</span> is attributed to complicated dynamic processes occurring in a collisionless space <span class="hlt">plasma</span> during geomagnetic perturbations and near the magnetic reconnection regions. The models that describe thin current structures in the Earth's magnetotail are reviewed. They are based on the assumption of the quasi-adiabatic ion dynamics in a relatively weak magnetic field of the magnetotail neutral <span class="hlt">sheet</span>, where the ions can become unmagnetized. It is shown that the ion distribution can be represented as a function of the integrals of particle motion-the total energy and quasi-adiabatic invariant. Various modifications of the initial equilibrium are considered that are obtained with allowance for the currents of magnetized <span class="hlt">electrons</span>, the contribution of oxygen ions, the asymmetry of <span class="hlt">plasma</span> sources, and the effects related to the non-Maxwellian particle distributions. The theoretical results are compared with the observational data from the Cluster spacecraft mission. Various <span class="hlt">plasma</span> instabilities developing in thin current <span class="hlt">sheets</span> are investigated. The evolution of the tearing mode is analyzed, and the parameter range in which the mode can grow are determined. The paradox of complete stabilization of the tearing mode in current <span class="hlt">sheets</span> with a nonzero normal magnetic field component is thereby resolved based on the quasi-adiabatic model. It is shown that, over a wide range of current <span class="hlt">sheet</span> parameters and the propagation directions of large-scale unstable waves, various modified drift instabilities-kink and sausage modes-can develop in the system. Based on the concept of a turbulent electromagnetic field excited as a result of the development and saturation of unstable waves, a mechanism for charged particle acceleration in turbulent current <span class="hlt">sheets</span> is proposed and the energy spectra of the accelerated particles are obtained.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000023162','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000023162"><span id="translatedtitle"><span class="hlt">Plasma</span> <span class="hlt">Sheet</span> Source and Loss Processes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lennartsson, O. W.</p> <p>2000-01-01</p> <p>Data from the TIMAS ion mass spectrometer on the Polar satellite, covering 15 ev/e to 33 keV/e in energy and essentially 4(pi) in view angles, are used to investigate the properties of earthward (sunward) field-aligned flows of ions, especially protons, in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>-lobe transition region near local midnight. A total of 142 crossings of this region are analyzed at 12-sec time resolution, all in the northern hemisphere, at R(SM) approx. 4 - 7 R(sub E), and most (106) in the poleward (sunward) direction. Earthward proton flows are prominent in this transition region (greater than 50% of the time), typically appearing as sudden "blasts" with the most energetic protons (approx. 33 keV) arriving first with weak flux, followed by protons of decreasing energy and increasing flux until either: (1) a new "blast" appears, (2) the flux ends at a sharp boundary, or (3) the flux fades away within a few minutes as the mean energy drops to a few keV. Frequent step-like changes (less than 12 sec) of the flux suggest that perpendicular gradients on the scale of proton gyroradii are common. Peak flux is similar to central <span class="hlt">plasma</span> <span class="hlt">sheet</span> proton flux (10(exp 5) - 10(exp 6)/[cq cm sr sec keV/e] and usually occurs at E approx. 4 - 12 keV. Only the initial phase of each "blast" (approx. 1 min) displays pronounced field-alignment of the proton velocity distribution, consistent with the time-of-flight separation of a more or less isotropic source distribution with df/d(nu) less than 0. The dispersive signatures are often consistent with a source at R(SM) less than or equal to 30 R(sub E). No systematic latitudinal velocity dispersion is found, implying that the equatorial <span class="hlt">plasma</span> source is itself convecting. In short, the proton "blasts" appear as sudden local expansions of central <span class="hlt">plasma</span> <span class="hlt">sheet</span> particles along reconfigured ("dipolarized") magnetic field lines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25526132','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25526132"><span id="translatedtitle">Bright subcycle extreme ultraviolet bursts from a single dense relativistic <span class="hlt">electron</span> <span class="hlt">sheet</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ma, W J; Bin, J H; Wang, H Y; Yeung, M; Kreuzer, C; Streeter, M; Foster, P S; Cousens, S; Kiefer, D; Dromey, B; Yan, X Q; Meyer-ter-Vehn, J; Zepf, M; Schreiber, J</p> <p>2014-12-01</p> <p>Double-foil targets separated by a low density <span class="hlt">plasma</span> and irradiated by a petawatt-class laser are shown to be a copious source of coherent broadband radiation. Simulations show that a dense <span class="hlt">sheet</span> of relativistic <span class="hlt">electrons</span> is formed during the interaction of the laser with the tenuous <span class="hlt">plasma</span> between the two foils. The coherent motion of the <span class="hlt">electron</span> <span class="hlt">sheet</span> as it transits the second foil results in strong broadband emission in the extreme ultraviolet, consistent with our experimental observations. PMID:25526132</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21180385','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21180385"><span id="translatedtitle">Observations of Double Layers in Earth's <span class="hlt">Plasma</span> <span class="hlt">Sheet</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ergun, R. E.; Tao, J.; Andersson, L.; Eriksson, S.; Johansson, T.; Angelopoulos, V.; Bonnell, J.; McFadden, J. P.; Larson, D. E.; Cully, C. M.; Newman, D. N.; Goldman, M. V.; Roux, A.; LeContel, O.; Glassmeier, K.-H.; Baumjohann, W.</p> <p>2009-04-17</p> <p>We report the first direct observations of parallel electric fields (E{sub parallel}) carried by double layers (DLs) in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> of Earth's magnetosphere. The DL observations, made by the THEMIS spacecraft, have E{sub parallel} signals that are analogous to those reported in the auroral region. DLs are observed during bursty bulk flow events, in the current <span class="hlt">sheet</span>, and in <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer, all during periods of strong magnetic fluctuations. These observations imply that DLs are a universal process and that strongly nonlinear and kinetic behavior is intrinsic to Earth's <span class="hlt">plasma</span> <span class="hlt">sheet</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19518640','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19518640"><span id="translatedtitle">Observations of double layers in earth's <span class="hlt">plasma</span> <span class="hlt">sheet</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ergun, R E; Andersson, L; Tao, J; Angelopoulos, V; Bonnell, J; McFadden, J P; Larson, D E; Eriksson, S; Johansson, T; Cully, C M; Newman, D N; Goldman, M V; Roux, A; LeContel, O; Glassmeier, K-H; Baumjohann, W</p> <p>2009-04-17</p> <p>We report the first direct observations of parallel electric fields (E_{ parallel}) carried by double layers (DLs) in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> of Earth's magnetosphere. The DL observations, made by the THEMIS spacecraft, have E_{ parallel} signals that are analogous to those reported in the auroral region. DLs are observed during bursty bulk flow events, in the current <span class="hlt">sheet</span>, and in <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer, all during periods of strong magnetic fluctuations. These observations imply that DLs are a universal process and that strongly nonlinear and kinetic behavior is intrinsic to Earth's <span class="hlt">plasma</span> <span class="hlt">sheet</span>. PMID:19518640</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002JGRA..107.1342S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002JGRA..107.1342S"><span id="translatedtitle">Multistage substorm expansion: Auroral dynamics in relation to <span class="hlt">plasma</span> <span class="hlt">sheet</span> particle injection, precipitation, and <span class="hlt">plasma</span> convection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sandholt, Per Even; Farrugia, Charles J.; Lester, Mark; Cowley, Stan; Milan, Steve; Denig, William F.; Lybekk, BjRn; Trondsen, Espen; Vorobjev, Vjacheslav</p> <p>2002-11-01</p> <p>We present observations of the auroral expansions during two substorms, focusing on multistage intensifications and the morphology of the poleward boundary, and relate these auroral observations to the local <span class="hlt">plasma</span> convection and <span class="hlt">plasma</span> <span class="hlt">sheet</span> dynamics. The observations are made by meridian scanning photometers and an all-sky camera (ASC) at Ny lesund, Svalbard (76 magnetic latitude (MLAT)), an ASC in Lovozero, Russia (64 MLAT), the International Monitor for Auroral Geomagnetic Effects (IMAGE) magnetometer chain in Svalbard and Scandinavia, the HYDRA instrument on Polar located at the inner edge of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, particle detectors on DMSP F13 and DMSP F14 traversing the ionospheric projection of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, and the CUTLASS Finland HF radar. In each substorm the aurora between 70 and 80 MLAT consisted of two branches separated by 5 in MLAT. The higher-latitude branch (at 75-78MLAT) was subject to a sequence of short-lived (1-2 min) intensifications, so-called "poleward boundary intensifications" (PBIs), recurring at 3-min intervals. Subsequent to each brightening, auroral forms traveled equatorward at a speed of 1.0-1.5 km s-1. On Polar the PBIs are related on a one-to-one basis with injections of <span class="hlt">electrons</span> in the 5- to 20-keV energy range at the inner edge of the equatorial <span class="hlt">plasma</span> <span class="hlt">sheet</span> with predominantly a trapped distribution, delayed by 5 min. <span class="hlt">Electron</span> precipitation within 60-77 MLAT, corresponding to a large radial extent of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, is documented by DMSP flights in the 1800-2000 magnetic local time (MLT) sector. In discussing the branches of the high-latitude aurora within the context of current understanding of the relation of bursty bulk flows to substorm expansion phase dynamics, we note the following: (1) the initial auroral breakup located at 63-64 MLAT near the equatorward edge of <span class="hlt">plasma</span> <span class="hlt">sheet</span> precipitation, which was followed by (2) two successive brightenings/auroral expansions appearing within 72-74 MLAT/2100 MLT, separated by 14 min, (3) a 20-min-long brightening sequence in the poleward auroral branch (75-78 MLAT), consisting of six discrete events (PBIs) within the boundary <span class="hlt">plasma</span> <span class="hlt">sheet</span> precipitation, and (4) the presence of auroral vortex motion/strong field-aligned current <span class="hlt">sheets</span> in some of these PBIs, which were accompanied by (5) <span class="hlt">electron</span> injections at the inner edge of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, (6) brightenings of the lower-latitude auroral branch when equatorward moving auroral forms (EMAFs/streamers) arrive there, and (7) localized bursts of equatorward ionospheric convection at speeds of 0.5-1 km s-1 in the latitude range of the EMAFs/streamers. The documented associations between PBIs/EMAFs, <span class="hlt">plasma</span> <span class="hlt">sheet</span> injections, and the local convection events are explained in terms of a substorm scenario involving bursty bulk flows in the late expansion phase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900063368&hterms=Uranus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DUranus','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900063368&hterms=Uranus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DUranus"><span id="translatedtitle">A pincer-shaped <span class="hlt">plasma</span> <span class="hlt">sheet</span> at Uranus</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hammond, C. Max; Walker, Raymond J.; Kivelson, Margaret G.</p> <p>1990-01-01</p> <p>An MHD simulation of the terrestrial magnetosphere, rescaled to represent the Uranian magnetotail, is carried out. The 3p immersion can be explained in terms of possible extreme departures from average <span class="hlt">plasma</span> <span class="hlt">sheet</span> shapes in the Uranian magnetosphere. The orientation of the Uranian dipole and rotation axes produce a dynamically curved <span class="hlt">plasma</span> <span class="hlt">sheet</span> which is an unusual feature of the Uranian magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22299938','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22299938"><span id="translatedtitle">Early results of microwave transmission experiments through an overly dense rectangular <span class="hlt">plasma</span> <span class="hlt">sheet</span> with microparticle injection</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gillman, Eric D.; Amatucci, W. E.</p> <p>2014-06-15</p> <p>These experiments utilize a linear hollow cathode to create a dense, rectangular <span class="hlt">plasma</span> <span class="hlt">sheet</span> to simulate the <span class="hlt">plasma</span> layer surrounding vehicles traveling at hypersonic velocities within the Earth's atmosphere. Injection of fine dielectric microparticles significantly reduces the <span class="hlt">electron</span> density and therefore lowers the <span class="hlt">electron</span> <span class="hlt">plasma</span> frequency by binding a significant portion of the bulk free <span class="hlt">electrons</span> to the relatively massive microparticles. Measurements show that microwave transmission through this previously overly dense, impenetrable <span class="hlt">plasma</span> layer increases with the injection of alumina microparticles approximately 60 μm in diameter. This method of <span class="hlt">electron</span> depletion is a potential means of mitigating the radio communications blackout experienced by hypersonic vehicles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA.....5006R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA.....5006R"><span id="translatedtitle">Current <span class="hlt">sheet</span> bifurcations observed by Cluster during <span class="hlt">plasma</span> <span class="hlt">sheet</span> flapping</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Runov, A.; Sergeev, V.; Baumjohann, W.; Nakamura, R.; Balogh, A.; Klecker, B.; Reme, H.; Sauvaud, J.-A.; Andre, M.</p> <p>2003-04-01</p> <p>We examined the structure of the tail current <span class="hlt">sheet</span> at XGSM-19~R_E using fast flapping oscillation. It was found that during 1055 -1107 UT on 29 August 2001 and 2220 - 2235 UT on 26 September 2001, following substorm intensifications, the flapping current <span class="hlt">sheet</span> displayed a clearly bifurcated structure with current density peaks at |B_x|0.5~B_L and a pronounced broad current density minimum in between. In both cases the bifurcation was associated with the current <span class="hlt">sheet</span> flapping in the Y-Z plane, with very large tilts (exceeding 45o). The origins of current bifurcation and of severe flapping motions are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6695110','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6695110"><span id="translatedtitle"><span class="hlt">Plasma</span> processes driven by current <span class="hlt">sheets</span> and their relevance to the auroral <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Singh, N.; Thiemann, H.; Schunk, R.W.</p> <p>1986-12-01</p> <p>Satellite and rocket observations have revealed a host of auroral <span class="hlt">plasma</span> processes, including large dc perpendicular electric fields (E /sub perpendicular/) associated with electrostatic shocks, relatively weak parallel electric fields (E /sub parallel/) associated with double layers, upflowing ions in the form of beams and conics, downflowing and upflowing accelerated <span class="hlt">electron</span> beams, several wave modes such as the electrostatic ion-cyclotron (EIC), lower hybrid (LH), very low frequency (VLF), extremely low frequency (ELF), and high-frequency waves and associated non-linear phenomena. Recently, the authors have attempted to simulate the various processes using a two-dimensional particle-in-cell code in which the <span class="hlt">plasma</span> is driven by current <span class="hlt">sheets</span> of a finite thickness. Striking similarities between the observed auroral <span class="hlt">plasma</span> processes and those seen in the simulations are found. In this paper they give a review of the <span class="hlt">plasma</span> processes dealing with dc and ac electric fields, formation of ion beams and conics, and <span class="hlt">electron</span> acceleration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMSM43B1766S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMSM43B1766S"><span id="translatedtitle">Modelling of the Turbulent <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> for Different Geomagnetic Conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stepanova, M. V.; Antonova, E. E.</p> <p>2009-12-01</p> <p>Recent studies has been shown the importance of turbulent processes for the development of self-consistent approach for the dynamics of the magnetosphere of the Earth, in particular, for the analysis of the stability of turbulent <span class="hlt">plasma</span> <span class="hlt">sheet</span>. Fluctuations of the <span class="hlt">plasma</span> bulk velocity were deduced from the measurements on board Interball/Tail, Cluster, Geotail, and Themis satellites. It was found that the <span class="hlt">plasma</span> <span class="hlt">sheet</span> flow generally appears to be strongly turbulent, i.e. dominated by fluctuations that are unpredictable. Corresponding eddy-diffusion coefficients were derived using the autocorrelation time and rms velocity. Variations of eddy-diffusion coefficients and particle density across and along the <span class="hlt">plasma</span> <span class="hlt">sheet</span> were studied, determining the characteristic values of eddy diffusion and of particle density as well as the thickness of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. The results obtained have been used for direct verification of the Antonova and Ovchinnikov (1996, 1998, 1999) theory of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> formation, according to which a compact and comparatively stable turbulent <span class="hlt">plasma</span> <span class="hlt">sheet</span> can be formed when the regular <span class="hlt">plasma</span> transport related to the regular dawn-dusk electric field across the <span class="hlt">plasma</span> <span class="hlt">sheet</span> is compensated by the eddy diffusion turbulent transport. When the turbulent fluctuations act to expand the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, the large-scale electrostatic dawn-dusk electric field counteracts to compress it, similarly to the case of the laboratory pinch which is compressed by the induction electric field. When the expansion and compression compensate each other, a stationary structure is formed. Our results have shown that this theory reproduces the dynamics of the turbulent <span class="hlt">plasma</span> <span class="hlt">sheet</span>, including its thickness, within the accuracy of parameters used.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeoRL..42.7867F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeoRL..42.7867F"><span id="translatedtitle">Imaging the development of the cold dense <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fuselier, S. A.; Dayeh, M. A.; Livadiotis, G.; McComas, D. J.; Ogasawara, K.; Valek, P.; Funsten, H. O.; Petrinec, S. M.</p> <p>2015-10-01</p> <p>The Interstellar Boundary Explorer (IBEX) frequently images the Earth's magnetosphere in Energetic Neutral Atoms (ENAs). In May 2013, there was an extended period of northward interplanetary magnetic field (IMF) while IBEX was imaging the Earth's magnetotail. During this period, IBEX imaged the development of the cold <span class="hlt">plasma</span> <span class="hlt">sheet</span> between about 15 and 20 Earth radii (RE) down the tail from the Earth. The ENA fluxes changed in both amplitude and average energy during this development. In addition, the <span class="hlt">plasma</span> <span class="hlt">sheet</span> may have thickened. At the end of the interval, the IMF turned southward and ENA fluxes decreased. The thickening of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> suggests that the <span class="hlt">plasma</span> in this region increases in both density and volume as it develops during extended periods of northward IMF. The decrease in the ENA flux suggests thinning of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and loss of <span class="hlt">plasma</span> associated with the IMF turning.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011EOSTr..92R.140T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011EOSTr..92R.140T"><span id="translatedtitle">Research Spotlight: First images of Earth's <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tretkoff, Ernie</p> <p>2011-04-01</p> <p>New images from the Interstellar Boundary Explorer (IBEX) mission capture for the first time part of Earth's magnetosphere. The new observations, described by McComas et al., provide the first images of the extended terrestrial <span class="hlt">plasma</span> <span class="hlt">sheet</span>, the <span class="hlt">sheet</span> separating the north and south lobes of the magnetosphere. The <span class="hlt">plasma</span> <span class="hlt">sheet</span> cannot be seen in images in visible light; the IBEX images were created using detections of energetic neutral atoms. One of the images captured what appears to be a magnetic disconnection event, in which magnetic field lines tear and part of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> pinches off from the rest. These types of disconnections release energy and can cause charged particles to be accelerated toward Earth, potentially disrupting satellites. This is the first time that a <span class="hlt">plasma</span> <span class="hlt">sheet</span> disconnection event may have been directly seen. (Journal of Geophysical Research-Space Physics, doi:10.1029/2010JA016138, 2011)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930039190&hterms=decrease+temperature+altitude&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Ddecrease%2Btemperature%2Baltitude','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930039190&hterms=decrease+temperature+altitude&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Ddecrease%2Btemperature%2Baltitude"><span id="translatedtitle">Ion temperature profiles in the horns of the <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Suszcynsky, D. M.; Gosling, J. T.; Thomsen, M. F.</p> <p>1993-01-01</p> <p>The <span class="hlt">plasma</span> <span class="hlt">sheet</span> horns are the low-altitude extensions of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> that lie poleward of the plasmasphere and equatorward of the tail lobes. Within the horns, magnetic field lines of increasing geomagnetic latitudes map to increasing distances into the downtail <span class="hlt">plasma</span> <span class="hlt">sheet</span>. <span class="hlt">Plasma</span> data from the fast <span class="hlt">plasma</span> experiment on ISEE 2 have been analyzed for 11 outbound crossings of the horns in the premidnight sector of the magnetosphere at typical altitudes of 2-4 R(E). These crossings typically occurred on time scales of less than 1 hour, providing almost instantaneous snapshots of <span class="hlt">plasma</span> gradients within the horns. Ion temperatures observed during these crossings generally decreased by a factor of four to eight as magnetic field lines of increasing geomagnetic latitude were traversed. If we make the reasonable assumption that the ion temperatures are constant along the field lines within the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, then this result implies that the ion temperatures in the downtail <span class="hlt">plasma</span> <span class="hlt">sheet</span> also commonly decrease by this same factor over the radial range extending from the inner edge of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> at the plasmapause boundary to the outer edge at a neutral line in the distant tail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19880044581&hterms=plasma+energy&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dplasma%2Benergy','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19880044581&hterms=plasma+energy&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dplasma%2Benergy"><span id="translatedtitle">Energy spectra of <span class="hlt">plasma</span> <span class="hlt">sheet</span> ions and <span class="hlt">electrons</span> from about 50 eV/e to about 1 MeV during plamsa temperature transitions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Christon, S. P.; Mitchell, D. G.; Williams, D. J.; Frank, L. A.; Huang, C. Y.; Eastman, T. E.</p> <p>1988-01-01</p> <p>ISEE-1 charged-particle measurements obtained during eight <span class="hlt">plasma</span> temperature transitions (PTTs) in 1978-1979 are compiled in tables and graphs and analyzed in detail, comparing the ion and <span class="hlt">electron</span> differential energy spectra with the predictions of theoretical models. PTTs are defined as approximately 1-h periods of low bulk <span class="hlt">plasma</span> velocity and steadily increasing or decreasing thermal energy. A Maxwellian distribution is found to be inadequate in describing the PTT energy spectra, but velocity-exponential and kappa distributions are both successful, the latter especially at higher energies. The power-law index kappa varies from PTT to PTT, but the high-energy spectral index and overall shape of the distribution remain constant during a PTT; both spatial and temporal effects are observed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFMSM24A..02P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFMSM24A..02P"><span id="translatedtitle">Closure of Field-Aligned Currents in the Near-Earth <span class="hlt">Plasma</span> <span class="hlt">Sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pritchett, P. L.; Coroniti, F. V.</p> <p>2006-12-01</p> <p>It has long been realized that the magnetosphere and ionosphere are intimately coupled by field-aligned-currents (FACs). While the role of the ionosphere in generating and closing these FACs is relatively well understood, little quantitative understanding exists as to how the magnetosphere's collisionless <span class="hlt">plasma</span> adjusts to either generate FAC by diverting cross-field current or close FACs across the magnetic field. Three-dimensional particle-in-cell <span class="hlt">plasma</span> kinetic simulations are used to investigate how the <span class="hlt">plasma</span> <span class="hlt">sheet</span> stress and electromagnetic fields respond to isolated flux tubes carrying downward or upward FACs. The downward FAC is created by injecting an <span class="hlt">electron</span> beam at the inner boundary; the upward FAC is created by extracting and not replacing the <span class="hlt">electrons</span> that precipitate at this boundary. The <span class="hlt">plasma</span> <span class="hlt">sheet</span> is driven by the imposition of an external convection electric field. The two FAC flux tubes create regions of electrostatic potential with opposite polarities in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. Initial results show that the downward current can divert cross-tail current over a significant radial distance in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. The self-generated magnetic field creates a shear in the equatorial magnetic field, with a localized reduction in the field extending in toward the inner boundary. This eventually leads to a localized reversal in the B_z field well earthward of the minimum in B_z caused by the externally-driven convection. The resulting complex dynamics of the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19720058742&hterms=wolf+conservation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dwolf%2Bconservation','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19720058742&hterms=wolf+conservation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dwolf%2Bconservation"><span id="translatedtitle">On the balance of stresses in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rich, F. J.; Wolf, R. A.; Vasyliunas, V. M.</p> <p>1972-01-01</p> <p>The stress resulting from magnetic tension on the neutral <span class="hlt">sheet</span> must, in a steady state, be balanced by any one or a combination of (1) a pressure gradient in the direction along the axis of the tail, (2) a similar gradient of <span class="hlt">plasma</span> flow kinetic energy, and (3) the tension resulting from a pressure anisotropy within the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. Stress balance in the first two cases requires that the ratios h/LX and BZ/BX be of the same order of magnitude, where h is the half-thickness of the neutral <span class="hlt">sheet</span>, LX is the length scale for variations along the axis of the tail, and BZ and BX are the magnetic field components in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> just outside the neutral <span class="hlt">sheet</span>. The second case requires, in addition, that the <span class="hlt">plasma</span> flow speed within the neutral <span class="hlt">sheet</span> be of the order of or larger than the Alfven speed outside the neutral <span class="hlt">sheet</span>. Stress balance in the third case requires that just outside the neutral <span class="hlt">sheet</span> the <span class="hlt">plasma</span> pressure obey the marginal firehose stability condition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..DPPBO5014G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..DPPBO5014G"><span id="translatedtitle">Microwave measurements on a well-collimated dusty <span class="hlt">plasma</span> <span class="hlt">sheet</span> for communications blackout applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gillman, Eric; Amatucci, Bill</p> <p>2013-10-01</p> <p>A linear hollow cathode produces an <span class="hlt">electron</span> beam that is accelerated into a low pressure (50 to 150 mTorr) background of Argon, producing an <span class="hlt">electron</span> beam discharge. A relatively constant 170 Gauss axial magnetic field is produced by two electromagnet coils arranged in a Helmholtz configuration. This results in a well-collimated <span class="hlt">electron</span> beam, producing a 2-dimensional discharge <span class="hlt">sheet</span> (40 cm high by 30 cm wide by 1 cm thick) with densities as high as 1012 cm-3. The <span class="hlt">plasma</span> <span class="hlt">sheet</span> is intended to replicate the parameters of the <span class="hlt">plasma</span> layer produced around hypersonic and reentry vehicles. The <span class="hlt">electron</span> beam is accelerated vertically towards a grounded beam dump electrode. This electrode is modified to include an array of six piezo buzzers modified and filled with alumina powder. When powered with a modest voltage, the piezoelectric shakers drop dust particles into the <span class="hlt">plasma</span> <span class="hlt">sheet</span> discharge directly below. A transmitting microwave horn is oriented normal to the dense <span class="hlt">plasma</span> <span class="hlt">sheet</span> while the receiving horn is mounted on a stage that can be rotated up to 180 degrees azimuthally. Microwave transmission and scattering measurements of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> are made in the S-band and X-band for applications related to communications blackout. This research was performed while the primary author held a National Research Council Research Associateship Award at the Naval Research Laboratory.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_3 --> <div id="page_4" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="61"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.8968P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.8968P"><span id="translatedtitle"><span class="hlt">Plasma</span> <span class="hlt">Sheet</span> Dynamics Imposed by Bursty Bulk Flows</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Panov, E. V.</p> <p>2009-04-01</p> <p>On 17 March 2008 around 9:12 UT the five Themis spacecraft were located in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> no more than 1 hour MLT apart and cover ed radial distances from 15 Re (THB) to about 10 Re (THA). We found that all the spacecraft consecutively observed a bursty bulk flow traveling first earthward, slowing down between THB and THA from 400 km/s to 50 km/s, and then changing toward the opposite direction. We found that the most tailward located spacecraft, THB and THC, detected thinning and then thickening of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> around the time of the flow direction change. The <span class="hlt">plasma</span> <span class="hlt">sheet</span> thinning propagated from THB to THC at about the Alfvén velocity in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer. Both spacecraft showed signatures of crossing the reconnection separatrix. On the other hand, we found that the THA, THD and THE spacecraft, which were located in a more dipolar region, indicated first <span class="hlt">plasma</span> <span class="hlt">sheet</span> thickening and then thinning. The five spacecraft observations can well be explained as the observation of the reconnected magnetic flux, which first moved toward a more dipolar field region close to the Earth, and then bounced tailward. Finally, we discuss the Pi2 pulsations observed by ground based magnetometers during these space observations, and also the non-adiabatic heating of particles inside the <span class="hlt">plasma</span> <span class="hlt">sheet</span> found after the <span class="hlt">sheet</span>'s thinning-thickening motion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19810019186','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19810019186"><span id="translatedtitle">Multiple crossings of a very thin <span class="hlt">plasma</span> <span class="hlt">sheet</span> in the Earth's magnetotail</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fairfield, D. H.; Hones, E. W., Jr.; Meng, C. I.</p> <p>1981-01-01</p> <p>High resolution magnetic field, <span class="hlt">plasma</span> and energetic particle data from the IMP-8 spacecraft were studied for multiple crossings of the Earth's magnetotail <span class="hlt">plasma</span> <span class="hlt">sheet</span> when it becomes thin during magnetospheric substorms. Traversals recur on a time scale of several minutes and they are associated with high velocity <span class="hlt">plasma</span> flows that are usually directed tailward but are occasionally directed earthward for brief intervals. Observations are explained by rapid oscillations of a <span class="hlt">plasma</span> <span class="hlt">sheet</span> that is only a few thousand km thick, a dimension comparable to the gyroradius of energetic protons. Differences in the angular distributions of the two energies indicate that the higher energy protons are preferentially located on field lines deeper in the tail lobe. A neutral line acceleration model is supported tailward streaming energetic <span class="hlt">electrons</span> which are occasionally present at the lobe <span class="hlt">plasma</span> <span class="hlt">sheet</span> interface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.5009L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.5009L"><span id="translatedtitle">Azimuthal flow bursts in the inner <span class="hlt">plasma</span> <span class="hlt">sheet</span> and possible connection with SAPS and <span class="hlt">plasma</span> <span class="hlt">sheet</span> earthward flow bursts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lyons, L. R.; Nishimura, Y.; Gallardo-Lacourt, B.; Nicolls, M. J.; Chen, S.; Hampton, D. L.; Bristow, W. A.; Ruohoniemi, J. M.; Nishitani, N.; Donovan, E. F.; Angelopoulos, V.</p> <p>2015-06-01</p> <p>We have combined radar observations and auroral images obtained during the Poker Flat Incoherent Scatter Radar Ion Neutral Observations in the Thermosphere campaign to show the common occurrence of westward moving, localized auroral brightenings near the auroral equatorward boundary and to show their association with azimuthally moving flow bursts near or within the subauroral polarization stream (SAPS) region. These results indicate that the SAPS region, rather than consisting of relatively stable proton precipitation and westward flows, can have rapidly varying flows, with speeds varying from ~100 m/s to ~1 km/s in just a few minutes. The auroral brightenings are associated with bursts of weak <span class="hlt">electron</span> precipitation that move westward with the westward flow bursts and extend into the SAPS region. Additionally, our observations show evidence that the azimuthally moving flow bursts often connect to earthward (equatorward in the ionosphere) <span class="hlt">plasma</span> <span class="hlt">sheet</span> flow bursts. This indicates that rather than stopping or bouncing, some flow bursts turn azimuthally after reaching the inner <span class="hlt">plasma</span> <span class="hlt">sheet</span> and lead to the bursts of strong azimuthal flow. Evidence is also seen for a general guiding of the flow bursts by the large-scale convection pattern, flow bursts within the duskside convection being azimuthally turned to the west, and those within the dawn cell being turned toward the east. The possibility that the SAPS region flow structures considered here may be connected to localized flow enhancements from the polar cap that cross the nightside auroral poleward boundary and lead to flow bursts within the <span class="hlt">plasma</span> <span class="hlt">sheet</span> warrants further consideration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/12686993','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/12686993"><span id="translatedtitle">Cold ions in the hot <span class="hlt">plasma</span> <span class="hlt">sheet</span> of Earth's magnetotail.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Seki, Kanako; Hirahara, Masafumi; Hoshino, Masahiro; Terasawa, Toshio; Elphic, Richard C; Saito, Yoshifumi; Mukai, Toshifumi; Hayakawa, Hajime; Kojima, Hirotsugu; Matsumoto, Hiroshi</p> <p>2003-04-10</p> <p>Most visible matter in the Universe exists as <span class="hlt">plasma</span>. How this <span class="hlt">plasma</span> is heated, and especially how the initial non-equilibrium <span class="hlt">plasma</span> distributions relax to thermal equilibrium (as predicted by Maxwell-Boltzman statistics), is a fundamental question in studies of astrophysical and laboratory <span class="hlt">plasmas</span>. Astrophysical <span class="hlt">plasmas</span> are often so tenuous that binary collisions can be ignored, and it is not clear how thermal equilibrium develops for these 'collisionless' <span class="hlt">plasmas</span>. One example of a collisionless <span class="hlt">plasma</span> is the Earth's <span class="hlt">plasma</span> <span class="hlt">sheet</span>, where thermalized hot <span class="hlt">plasma</span> with ion temperatures of about 5 x 10(7) K has been observed. Here we report direct observations of a <span class="hlt">plasma</span> distribution function during a solar eclipse, revealing cold ions in the Earth's <span class="hlt">plasma</span> <span class="hlt">sheet</span> in coexistence with thermalized hot ions. This cold component cannot be detected by <span class="hlt">plasma</span> sensors on satellites that are positively charged in sunlight, but our observations in the Earth's shadow show that the density of the cold ions is comparable to that of hot ions. This high density is difficult to explain within existing theories, as it requires a mechanism that permits half of the source <span class="hlt">plasma</span> to remain cold upon entry into the hot turbulent <span class="hlt">plasma</span> <span class="hlt">sheet</span>. PMID:12686993</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008GeoRL..3524201C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008GeoRL..3524201C"><span id="translatedtitle">Direct observation of warping in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> of Saturn</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carbary, J. F.; Mitchell, D. G.; Paranicas, C.; Roelof, E. C.; Krimigis, S. M.</p> <p>2008-12-01</p> <p>The ENA images from the Ion Neutral CAmera (INCA) on the Cassini spacecraft are projected onto the noon-midnight plane of Sun-Saturn orbital coordinates, and a composite ``image'' of Saturn's <span class="hlt">plasma</span> <span class="hlt">sheet</span> is constructed from dawn-side observations of 20-50 keV hydrogens obtained from days 352 to 361 in 2004. The maxima in the intensity contours define the center of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> in the noon-midnight plane. This <span class="hlt">plasma</span> <span class="hlt">sheet</span> surface displays a distinct bending or ``warping'' above Saturn's equatorial plane at radial distances of beyond ~15 RS on the nightside. On the dayside, the <span class="hlt">plasma</span> <span class="hlt">sheet</span> lies close to the equator all the way to the magnetopause. The observed warping agrees with the ``bowl'' model derived from measurements of Saturn's magnetic field, but fits more closely a simple third-order polynomial.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010GeoRL..3721101K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010GeoRL..3721101K"><span id="translatedtitle">Escape of O+ through the distant tail <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kistler, L. M.; Galvin, A. B.; Popecki, M. A.; Simunac, K. D. C.; Farrugia, C.; Moebius, E.; Lee, M. A.; Blush, L. M.; Bochsler, P.; Wurz, P.; Klecker, B.; Wimmer-Schweingruber, R. F.; Opitz, A.; Sauvaud, J.-A.; Thompson, B.; Russell, C. T.</p> <p>2010-11-01</p> <p>In February 2007, the STEREO-B spacecraft encountered the magnetosheath, <span class="hlt">plasma</span> <span class="hlt">sheet</span> and <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer from about 200 RE to 300 RE downtail. This time period was during solar minimum, and there was no storm activity during this month. Using data from the PLASTIC instrument, we find that even during quiet times, O+ is a constant feature of the deep magnetotail, with an O+ density of about 15% of the O+ density in the near-earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> for similar conditions. The tailward flux of the O+ is similar to the flux of O+ beams that have been observed in the lobe/mantle region of the deep tail. The total outflow rate of the O+ down the <span class="hlt">plasma</span> <span class="hlt">sheet</span> is 1.1 × 1024 ions/s, which is 10% of the total outflow rate of 1 × 1025 ions/s, and of the same order as the estimated loss from dayside transport.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMSM33B1900K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMSM33B1900K"><span id="translatedtitle">Escape of O+ Through the Distant Tail <span class="hlt">Plasma</span> <span class="hlt">Sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kistler, L. M.; Galvin, A. B.; Popecki, M.; Simunac, K. D.; Farrugia, C. J.; Moebius, E.; Lee, M. A.; Blush, L. M.; Bochsler, P. A.; Wurz, P.; Klecker, B.; Wimmer-Schweingruber, R. F.; Opitz, A.; Sauvaud, J.; Russell, C. T.</p> <p>2010-12-01</p> <p>During the early orbit phase of the STEREO mission, in February, 2007, the STEREO-B spacecraft went down the deep magnetotail, and encountered the magnetosheath, <span class="hlt">plasma</span> <span class="hlt">sheet</span> and <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer from about 200 Re to 300 Re downtail, before finally exiting to the solar wind. This time period was during solar minimum, and there was no storm activity during this month. We have used the ion composition data from the PLASTIC instrument to determine how much ionospheric O+ is in the deep tail <span class="hlt">plasma</span> <span class="hlt">sheet</span>, and to calculate the loss rate through this path. Surprisingly, we find that during this solar and geomagnetically quiet time, O+ is a constant feature of the deep magnetotail. We find that the O+ density is about 15% of the density in the near-earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> for similar conditions. The tailward flux of the O+ is similar to the flux of O+ beams that have been observed in the lobe/mantle region of the deep tail. The observations provide a consistent picture that some O+ is transported into the distant tail in the lobe/mantle region, and then enters the <span class="hlt">plasma</span> <span class="hlt">sheet</span> tailward of the distant neutral line. The total outflow of the O+ down the <span class="hlt">plasma</span> <span class="hlt">sheet</span> is a rate of 1.1x1024 ions/s, which is 10% of the total outflow rate of 1x 1025 ions/s, and of the same order as the estimated loss from dayside transport.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20722065','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20722065"><span id="translatedtitle">Experimental study of <span class="hlt">plasma</span> compression into the <span class="hlt">sheet</span> in three-dimensional magnetic fields with singular X lines</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Frank, Anna G.; Bogdanov, Sergey Yu.; Markov, Vladimir S.; Ostrovskaya, Galya V.; Dreiden, Galina V.</p> <p>2005-05-15</p> <p>The formation and evolution of the <span class="hlt">plasma</span> <span class="hlt">sheets</span> resulting from the <span class="hlt">plasma</span> compression in diversified three-dimensional (3D) magnetic configurations with singular X lines are reported on. The research was focused on the correlation between the structure of a <span class="hlt">plasma</span> <span class="hlt">sheet</span> and the topology of the initial 3D magnetic configuration, especially on the impact of the guide field aligned with the X line. It has been demonstrated experimentally that <span class="hlt">plasma</span> compression and formation of extended <span class="hlt">plasma</span> <span class="hlt">sheets</span> can take place in configurations with the X lines in the presence of a strong guide field. The <span class="hlt">electron</span> density distributions in the <span class="hlt">plasma</span> <span class="hlt">sheets</span> were found to be rather sensitive to the magnetic field topology. The experiments revealed the effect of progressive decrease of the <span class="hlt">plasma</span> compression ratio in response to increasing guide field. This effect has two basic manifestations: a decrease of the maximum <span class="hlt">plasma</span> density and an enlargement of the <span class="hlt">sheet</span> thickness. Based on the experimental data we advanced a concept that the deterioration of <span class="hlt">plasma</span> compression into the <span class="hlt">sheet</span> is due to enhancement of the guide field inside the <span class="hlt">sheet</span> over its initial value, and due to excitation of additional currents in the plane perpendicular to the singular X line and to the original current in the <span class="hlt">sheet</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920041911&hterms=Ionosphere+heating&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DIonosphere%2Bheating','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920041911&hterms=Ionosphere+heating&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DIonosphere%2Bheating"><span id="translatedtitle">Nonadiabatic heating of the central <span class="hlt">plasma</span> <span class="hlt">sheet</span> at substorm onset</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Huang, C. Y.; Frank, L. A.; Rostoker, G.; Fennell, J.; Mitchell, D. G.</p> <p>1992-01-01</p> <p>Heating events in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer and central <span class="hlt">plasma</span> <span class="hlt">sheet</span> are found to occur at the onset of expansive phase activity. The main effect is a dramatic increase in <span class="hlt">plasma</span> temperature, coincident with a partial dipolarization of the magnetic field. Fluxes of energetic particles increase without dispersion during these events which occur at all radial distances up to 23 RE, the apogee of the ISEE spacecraft. A major difference between these heating events and those observed at geosynchronous distances lies in the heating mechanism which is nonadiabatic beyond 10 RE but may be adiabatic closer to earth. The energy required to account for the increase in <span class="hlt">plasma</span> thermal energy is comparable with that required for Joule heating of the ionosphere. The <span class="hlt">plasma</span> <span class="hlt">sheet</span> must be considered as a major sink in the energy balance of a substorm. Lobe magnetic pressures during these events are estimated. Change in lobe pressure are generally not correlated with onsets or intensifications of expansive phase activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008GeoRL..3517S13G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008GeoRL..3517S13G"><span id="translatedtitle">Propagation characteristics of <span class="hlt">plasma</span> <span class="hlt">sheet</span> oscillations during a small storm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gabrielse, C.; Angelopoulos, V.; Runov, A.; Kepko, L.; Glassmeier, K. H.; Auster, H. U.; McFadden, J.; Carlson, C. W.; Larson, D.</p> <p>2008-06-01</p> <p>On 24 March 2007, the THEMIS spacecraft were in a string-of-pearls configuration through the dusk <span class="hlt">plasma</span> <span class="hlt">sheet</span> at the recovery phase of a small storm. Large undulations of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> were observed that brought the five probes from one lobe to another. Each neutral <span class="hlt">sheet</span> crossing was accompanied by bursty bulk flows and Pi2 oscillations. In this paper we focus on the low frequency (~10 min) large scale <span class="hlt">plasma</span> <span class="hlt">sheet</span> undulations and determine their propagation characteristics, origin, and properties in the presence of storm-time substorms. As the first case of ``flapping waves'' observed and analyzed during storm-time, it is interesting to find their characteristics coincide with those described by previous quiet-time observations. These characteristics include flankward propagation of the undulations with velocities generally between ~40-130 km/s.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950037043&hterms=generation+proton+gradient&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dgeneration%2Bproton%2Bgradient','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950037043&hterms=generation+proton+gradient&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dgeneration%2Bproton%2Bgradient"><span id="translatedtitle">Auroral ionospheric signatures of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer in the evening sector</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Burke, W. J.; Machuzak, J. S.; Maynard, N. C.; Basinska, E. M.; Erickson, G. M.; Hoffman, R. A.; Slavin, J. A.; Hanson, W. B.</p> <p>1994-01-01</p> <p>We report on particles and fields observed during Defense Meteorological Satellite Program (DMSP) F9 and DE 2 crossings of the polar cap/auroral oval boundary in the evening magnetic local time (MLT) sector. Season-dependent, latitudinally narrow regions of rapid, eastward <span class="hlt">plasma</span> flows were encountered by DMSP near the poleward boundary of auroral <span class="hlt">electron</span> precipitation. Ten DE 2 orbits exhibiting electric field spikes that drive these <span class="hlt">plasma</span> flows were chosen for detailed analysis. The boundary region is characterized by pairs of oppositely-directed, field-aligned current <span class="hlt">sheets</span>. The more poleward of the two current <span class="hlt">sheets</span> is directed into the ionosphere. Within this downward current <span class="hlt">sheet</span>, precipitating <span class="hlt">electrons</span> either had average energies of a few hundred eV or were below polar rain flux levels. Near the transition to upward currents, DE 2 generally detected intense fluxes of accelerated <span class="hlt">electrons</span> and weak fluxes of ions, both with average energies between 5 and 12 keV. In two instances, precipitating ions with energies greater than 5 keV spanned both current <span class="hlt">sheets</span>. Comparisons with satellite measurements at higher altitudes suggest that the particles and fields originated in the magnetotail inside the distant reconnection region and propagated to Earth through the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer. Auroral <span class="hlt">electrons</span> are accelerated by parallel electric fields produced by the different pitch angle distributions of protons and <span class="hlt">electrons</span> in this layer interacting with the near-Earth magnetic mirror. Electric field spikes driving rapid <span class="hlt">plasma</span> flows along the poleward boundaries of intense, keV <span class="hlt">electron</span> precipitation represent ionospheric responses to the field-aligned currents and conductivity gradients. The generation of field-aligned currents in the boundary layer may be understood qualitatively as resulting from the different rates of earthward drift for <span class="hlt">electrons</span> and protons in the magnetotail's current <span class="hlt">sheet</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EP%26S...67..133S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EP%26S...67..133S"><span id="translatedtitle">On the <span class="hlt">plasma</span> <span class="hlt">sheet</span> dependence on solar wind and substorms and its role in magnetosphere-ionosphere coupling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sergeev, V. A.; Dmitrieva, N. P.; Stepanov, N. A.; Sormakov, D. A.; Angelopoulos, V.; Runov, A. V.</p> <p>2015-12-01</p> <p>Recently, it was argued that Hall conductivity and peak intensity of equivalent ionospheric currents are sensitive to the amount of field-aligned acceleration of <span class="hlt">plasma</span> <span class="hlt">sheet</span> (PS) <span class="hlt">electrons</span>, which in turn depends on the <span class="hlt">plasma</span> <span class="hlt">sheet</span> parameters T e and N e (<span class="hlt">electron</span> temperature and density) proportionally to the quantity eTN = ( T e)1/2/ N e. Here we extend these studies using data from six tail seasons of THEMIS observations to show statistically that the behavior of these PS <span class="hlt">electron</span> parameters, measured in the middle of the nightside <span class="hlt">plasma</span> <span class="hlt">sheet</span> at ~10 RE distance, depends in a very different way on two basic processes: the solar wind state and substorms. We confirm previous work that slow/dense (fast/tenuous) solar wind provides cold/dense (hot/tenuous) <span class="hlt">plasma</span> <span class="hlt">sheet</span> conditions. However, we find that <span class="hlt">electron</span> temperature and pressure parameters ( T e and P e) behave differently from the proton ones ( T p and P p), indicating a strong decoupling between temperature variations of auroral protons and <span class="hlt">electrons</span> in the central <span class="hlt">plasma</span> <span class="hlt">sheet</span> (CPS): <span class="hlt">electrons</span> are more sensitive to the substorm-related acceleration in the magnetotail than protons. Our superposed epoch study of <span class="hlt">plasma</span> <span class="hlt">sheet</span> parameter variations during substorms as well as our analysis of <span class="hlt">plasma</span> acceleration at dipolarization fronts shows that during the substorm expansion phase a new (accelerated and <span class="hlt">plasma</span>-depleted) population comes into the inner CPS with the flow bursts, showing an average increase of <span class="hlt">electron</span> temperature and eTN parameter roughly by a factor of 2 above its background values for both cold/dense and hot/tenuous <span class="hlt">plasma</span> <span class="hlt">sheet</span> states. Preferential <span class="hlt">electron</span> heating in the flow bursts is also statistically confirmed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JPhD...47L5501T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JPhD...47L5501T"><span id="translatedtitle">Microwave <span class="hlt">plasmas</span> applied for the synthesis of free standing graphene <span class="hlt">sheets</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tatarova, E.; Dias, A.; Henriques, J.; Botelho do Rego, A. M.; Ferraria, A. M.; Abrashev, M. V.; Luhrs, C. C.; Phillips, J.; Dias, F. M.; Ferreira, C. M.</p> <p>2014-09-01</p> <p>Self-standing graphene <span class="hlt">sheets</span> were synthesized using microwave <span class="hlt">plasmas</span> driven by surface waves at 2.45 GHz stimulating frequency and atmospheric pressure. The method is based on injecting ethanol molecules through a microwave argon <span class="hlt">plasma</span> environment, where decomposition of ethanol molecules takes place. The evolution of the ethanol decomposition was studied in situ by <span class="hlt">plasma</span> emission spectroscopy. Free gas-phase carbon atoms created in the <span class="hlt">plasma</span> diffuse into colder zones, both in radial and axial directions, and aggregate into solid carbon nuclei. The main part of the solid carbon is gradually withdrawn from the hot region of the <span class="hlt">plasma</span> in the outlet <span class="hlt">plasma</span> stream where nanostructures assemble and grow. Externally forced heating in the assembly zone of the <span class="hlt">plasma</span> reactor has been applied to engineer the structural qualities of the assembled nanostructures. The synthesized graphene <span class="hlt">sheets</span> have been analysed by Raman spectroscopy, scanning <span class="hlt">electron</span> microscopy, high-resolution transmission <span class="hlt">electron</span> microscopy and x-ray photoelectron spectroscopy. The presence of sp3 carbons is reduced by increasing the gas temperature in the assembly zone of the <span class="hlt">plasma</span> reactor. As a general trend, the number of mono-layers decreases when the wall temperature increases from 60 to 100 C. The synthesized graphene <span class="hlt">sheets</span> are stable and highly ordered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19880033104&hterms=earth+events&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dearth%2Bevents','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19880033104&hterms=earth+events&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dearth%2Bevents"><span id="translatedtitle">Simultaneous measurements of energetic ion (50 keV and above) and <span class="hlt">electron</span> (220 keV and above) activity upstream of earth's bow shock and inside the <span class="hlt">plasma</span> <span class="hlt">sheet</span> - Magnetospheric source for the November 3 and December 3, 1977 upstream events</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sarris, E. T.; Anagnostopoulos, G. C.; Krimigis, S. M.</p> <p>1987-01-01</p> <p>Simultaneous observations of energetic ions and <span class="hlt">electrons</span> by the IMP 7 and 8 spacecraft are used here to separate temporal variations from spatial variations during the upstream ion events observed on December 3, 1977 and November 2-3, 1977, in order to determine the source of these particles. Analysis of the observations and comparison with theory shows that: (1) for each of the observed upstream enhancements, energetic ions and <span class="hlt">electrons</span> were simultaneously present inside the <span class="hlt">plasma</span> <span class="hlt">sheet</span>; (2) the low-energy ion intensity profile inside the <span class="hlt">plasma</span> <span class="hlt">sheet</span> was relatively flat, while at higher energies there was considrable variability; (3) relativistic <span class="hlt">electron</span> bursts were seen inside the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and also upstream of the shock but at substantially reduced intensities; (4) the ion energy spectrum for the December 3 event, extended to energies of about 2 MeV, was identical in form with the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and upstream of the shock; (5) ion anisotropies exhibited typically large dawn-dusk or dusk-dawn gradients and large field-aligned streaming away from the bow shock.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900043492&hterms=earth+layers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dearth%2527s%2Blayers','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900043492&hterms=earth+layers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dearth%2527s%2Blayers"><span id="translatedtitle">Cold <span class="hlt">plasma</span> heating in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer - Theory and simulations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schriver, David; Ashour-Abdalla, Maha</p> <p>1990-01-01</p> <p>Satellite observations in recent years have confirmed that the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer is a permanent feature of the earth's magnetotail located between the lobe and central <span class="hlt">plasma</span> <span class="hlt">sheet</span> during both quiet and active magnetic periods. Distinct features of the boundary layer include field aligned ion beams and intense electrostatic emissions known as broadband electrostatic noise. Since the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer is a spatial feature of the magnetotail, within it will occur thermal mixing of the resident warm boundary layer <span class="hlt">plasma</span> with inflowing (convecting) cold ionospheric <span class="hlt">plasma</span>. A theoretical study involving linear theory and nonlinear numerical particle simulations is presented which examines ion beam instabilities in the presence of a thermally mixed hot and cold background <span class="hlt">plasma</span>. It is found that the free energy in the ion beams can heat the cool ionospheric <span class="hlt">plasma</span> to ambient <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer temperatures via broadband electrostatic noise. These results, along with recent observational reports that ionospheric outflow can account for measured <span class="hlt">plasma</span> <span class="hlt">sheet</span> densities, suggest that the ionospheric role in <span class="hlt">plasma</span> <span class="hlt">sheet</span> dynamics and content may be as large as the solar wind.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.6497P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.6497P"><span id="translatedtitle"><span class="hlt">Plasma</span> <span class="hlt">sheet</span> flow damping by oscillatory flow braking</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Panov, Evgeny V.; Leontyeva, Olga S.; Baumjohann, Wolfgang; Nakamura, Rumi; Amm, Olaf; Angelopoulos, Vassilis; Glassmeier, Karl-Heinz; Kubyshkina, Marina V.; Petrukovich, Anatoli A.; Sergeev, Victor A.; Weygand, James M.</p> <p>2015-04-01</p> <p>Using simultaneous observations in the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> by five Time History of Events and Macroscale Interactions during Substorms (THEMIS) probes, conjugate ground all-sky camera observations from Canada, and magnetometer networks over North America, we show that auroral bulge dynamics is modulated by a recently discovered process known as oscillatory flow braking, which occurs at about 10 Earth radii down the Earth's magnetotail. In oscillatory flow breaking, <span class="hlt">plasma</span> <span class="hlt">sheet</span> flows oscillating with different periods at various distances collide, producing pressure forces that exert shear stresses on the magnetic field, transiently amplifying the vertical magnetic field component. Sporadic fast relief of these stresses through significant particle precipitations causes damping of <span class="hlt">plasma</span> <span class="hlt">sheet</span> fast flows.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920045462&hterms=Plasma+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DPlasma%2Benergy','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920045462&hterms=Plasma+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DPlasma%2Benergy"><span id="translatedtitle">Low-energy particle layer outside of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Parks, G. K.; Fitzenreiter, R.; Ogilvie, K. W.; Huang, C.; Anderson, K. A.; Dandouras, J.; Frank, L.; Lin, R. P.; Mccarthy, M.; Reme, H.</p> <p>1992-01-01</p> <p>The ISEE spacecraft in the geomagnetic tail frequently crossed the high-latitude boundary of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. On a number of these crossings on the morningside (between 15 RE and 22 RE) the ISEE instruments detected an enhanced population of low-energy <span class="hlt">electrons</span> and ions immediately adjacent to the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer (PSBL). The <span class="hlt">electrons</span> in this low-energy layer (LEL) have energies less than a few hundred eV, and they are aligned along the magnetic field direction propagating in the tailward direction. The ions have energies less than 100 eV and are also streaming along the magnetic field direction but in the earthward direction. These particles are clearly distinguished from the bulk of the particles in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and the PSBL. These observations may help clarify where the various particle features in the geomagnetic tail map to in the ionosphere. It is suggested that the LEL maps to the soft (less than 1 keV) <span class="hlt">electron</span> precipitation region poleward of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSH43A4166W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSH43A4166W"><span id="translatedtitle">An Unusual Heliospheric <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> Crossing at 1 AU</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, C. C.; Liou, K.; Vourlidas, A.; Lepping, R. P.; Wang, Y. M.; Plunkett, S. P.; Socker, D. G.; Wu, S. T.</p> <p>2014-12-01</p> <p>At 11:46UT on September 9, 2011, the Wind spacecraft encountered an interplanetary (IP) fast forward shock. The shock was followed almost immediately (~5 minutes) by a short duration (~35 minutes), extremely large density pulse with a density peak of ~100 cm-3. While a sharp increase in the solar wind density is typical of an IP shock downstream, the unusual large density increase prompts a further investigation. After a close examination of other in situ data from Wind, we find the density pulse was associated with (1) a spike in the <span class="hlt">plasma</span> beta (ratio of thermal to magnetic pressure), (2) multiple sign changes in the azimuthal angle of magnetic field, (3) depressed magnetic field, (4) a small radial component of magnetic field, and (5) a large (>90 degrees) pitch-angle change in suprathermal <span class="hlt">electrons</span> (>200 eV) across the density pulse. We conclude that the density pulse is the heliospheric <span class="hlt">plasma</span> <span class="hlt">sheet</span> and the estimated thickness is ~820,000km. The unusually large density pulse is likely to be a result of the shock compression from behind. This view is supported by our 3D magnetohydrodynamic simulation. The detailed result and implications will be discussed. *This work is supported partially by ONR 6.1 program</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110024199','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110024199"><span id="translatedtitle"><span class="hlt">Plasma</span> <span class="hlt">Sheet</span> Velocity Measurement Techniques for the Pulsed <span class="hlt">Plasma</span> Thruster SIMP-LEX</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nawaz, Anuscheh; Lau, Matthew</p> <p>2011-01-01</p> <p>The velocity of the first <span class="hlt">plasma</span> <span class="hlt">sheet</span> was determined between the electrodes of a pulsed <span class="hlt">plasma</span> thruster using three measurement techniques: time of flight probe, high speed camera and magnetic field probe. Further, for time of flight probe and magnetic field probe, it was possible to determine the velocity distribution along the electrodes, as the <span class="hlt">plasma</span> <span class="hlt">sheet</span> is accelerated. The results from all three techniques are shown, and are compared for one thruster geometry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910063755&hterms=Chaos&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DChaos','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910063755&hterms=Chaos&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DChaos"><span id="translatedtitle">Chaos in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. [of geomagnetic tail</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goertz, Christoph K.; Smith, Robert A.; Shan, Lin-Hua</p> <p>1991-01-01</p> <p>A simple dynamical model of the magnetotail is discussed, in which the electric field in the current <span class="hlt">sheet</span> evolves in response to a solar-wind-induced electric field at the magnetopause, and depends on the specific entropy of the <span class="hlt">plasma</span> in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. The entropy varies due to nonadiabatic heating in a region where ULF waves are absorbed by resonant mode conversion. The feedback between temperature and entropy change leads to an evolution which exhibits chaos when the solar wind electric field is neither very small nor very large. The onset of chaos may be quite sudden or may proceed through a sequence of period doublings.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_4 --> <div id="page_5" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="81"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998APS..DPP.K6S06S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998APS..DPP.K6S06S"><span id="translatedtitle">Space Charge Effect in the <span class="hlt">Sheet</span> and Solid <span class="hlt">Electron</span> Beam</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Song, Ho Young; Kim, Hyoung Suk; Ahn, Saeyoung</p> <p>1998-11-01</p> <p>We analyze the space charge effect of two different types of <span class="hlt">electron</span> beam ; <span class="hlt">sheet</span> and solid <span class="hlt">electron</span> beam. <span class="hlt">Electron</span> gun simulations are carried out using shadow and control grids for high and low perveance. Rectangular and cylindrical geometries are used for <span class="hlt">sheet</span> and solid <span class="hlt">electron</span> beam in planar and disk type cathode. The E-gun code is used to study the limiting current and space charge loading in each geometries.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830024324','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830024324"><span id="translatedtitle">The inner edge of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and the diffuse aurora</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fairfield, D. H.; Vinas, A. F.</p> <p>1983-01-01</p> <p>Three dimensional measurements from the ISEE-1 low energy <span class="hlt">electron</span> spectrometer are used to map the location of the inner edge of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and study the anisotropies in the <span class="hlt">electron</span> distribution function associated with this boundary. Lower energy <span class="hlt">plasma</span> <span class="hlt">sheet</span> <span class="hlt">electrons</span> have inner edges closer to the Earth than higher energies with the separations at different energies being larger near dawn and after dusk than at midnight. Lowest energy inner edges are frequently located adjacent to the plasmapause in the dawn hemisphere but are often separated from it in the dusk hemisphere by a gap of at least several Re. The energy dispersion is minimal in the afternoon quadrant where the inner edge is near the magnetopause and frequently oscillating on a time scale of minutes. The location of the inner edge is probably determined primarily by the motion of <span class="hlt">electrons</span> in the existing electric and magnetic fields rather than by strong diffusion as has sometimes been supposed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015HEDP...17..208K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015HEDP...17..208K"><span id="translatedtitle">Preliminary characterization of a laser-generated <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Keiter, P. A.; Malamud, G.; Trantham, M.; Fein, J.; Davis, J.; Klein, S. R.; Drake, R. P.</p> <p>2015-12-01</p> <p>We present the results from recent experiments to create a flowing <span class="hlt">plasma</span> <span class="hlt">sheet</span>. Two groups of three laser beams with nominally 1.5 kJ of energy per group were focused to separate pointing locations, driving a shock into a wedge target. As the shock breaks out of the wedge, the <span class="hlt">plasma</span> is focused on center, creating a <span class="hlt">sheet</span> of <span class="hlt">plasma</span>. Measurements at 60 ns indicate the <span class="hlt">plasma</span> <span class="hlt">sheet</span> has propagated 2825 microns with an average velocity of 49 microns/ns. These experiments follow previous experiments [Krauland et al. 2013], which are aimed at studying similar physics as that found in the hot spot region of cataclysmic variables. Krauland et al. created a flowing <span class="hlt">plasma</span>, which represents the flowing <span class="hlt">plasma</span> from the secondary star. This flow interacted with a stationary object, which represented the disk around the white dwarf. A reverse shock is a shock formed when a freely expanding <span class="hlt">plasma</span> encounters an obstacle. Reverse shocks can be generated by a blast wave propagating through a medium. They can also be found in binary star systems where the flowing gas from a companion star interacts with the accretion disk of the primary star.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUSMSM44A..07L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUSMSM44A..07L"><span id="translatedtitle">On the Veracity of Fluid <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> Descriptions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lennartsson, O. W.</p> <p>2008-05-01</p> <p>A new generation of ion measurements with much improved time resolution, and the availability of simultaneous such measurements at multiple adjacent points, have made it clear that the <span class="hlt">plasma</span> <span class="hlt">sheet</span> has prominent granularity at the scale size of keV proton gyroradii (beyond a few RE from Earth). This scale size in itself defies a fluid description, and its presence in a non-uniform magnetic field has direct implications for the magnetization of the ions. The reason is that the ions, especially heavy ions, have much larger gyroradii than <span class="hlt">electrons</span> of similar energy and cannot uniformly neutralize the <span class="hlt">electrons</span> during mirroring. Resulting space charges readily demagnetize and accelerate ions, including outflowing ions from Earth. Data from the Polar TIMAS and Cluster CODIF instruments will be shown here to illustrate the prevalence of ion gyroradii-sized flux and density gradients, both at high latitude near Earth (~5 RE) and at the ~19 RE Cluster apogees near the tail equatorial plane. Specifically, the gradient scale lengths are often less than five local gyroradii of a 10-keV proton at 90 pitch angle. The anticipated effects are not amenable to a fluid description, but they do provide a reasonable physical context for discrete aurora formation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhDT........43Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhDT........43Y"><span id="translatedtitle">Empirical Modeling of 3D <span class="hlt">Plasma</span> Pressure and Magnetic Field Structures in the Earth's <span class="hlt">Plasma</span> <span class="hlt">Sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yue, Chao</p> <p></p> <p>Ions and <span class="hlt">electrons</span> in the nightside magnetosphere, driven by the dawn-to-dusk convection electric field, flow earthward and are energized. As a result, <span class="hlt">plasma</span> pressure is enhanced and magnetic field configuration becomes more stretched, forming the necessary conditions for the development of substorms. Determining the physical processes leading to the changes of the <span class="hlt">plasma</span> and magnetic field configurations, as well as the processes resulting from the configuration variations, is thus crucial to understanding substorms. Accurate evaluation of these processes, including formation of field-aligned currents (FACs), isotropization by current <span class="hlt">sheet</span> scattering, and some localized instabilities that may responsible for substorm onset, relies on knowing the realistic 3 dimensional (3D) magnetic field configurations, which cannot be provided by current available empirical models with sufficient accuracy or as a function of growth phase development. Therefore, we have developed a 3D force-balanced empirical substorm growth phase magnetic field model, which allows us to investigate the evolution of these configurations during the substorm growth phase and evaluate the physical processes governing the configuration changes. Here, we first statistically analyzed the growth phase pressures using Geotail and THEMIS data, and identified three primary factors causing the growth phase pressure change: solar wind dynamic pressure (PSW), energy loading, and sunspot number. We then constructed a 2D equatorial empirical pressure model and an error model in the near Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> (r ? 20 R E) using the Support Vector Regression Machine (SVRM) with the three factors as input. The model predicts the <span class="hlt">plasma</span> <span class="hlt">sheet</span> pressure accurately with median errors of 5%, and the predicted pressure gradients agree reasonably well with observed gradients obtained from two-probe measurements. The model shows that pressure increases linearly as PSW increases, while the pressure responses to energy loading and sunspot number are nonlinear. From these model pressure distributions, we were able to establish a realistic 3D growth phase magnetic field configurations that satisfy the physical constraint of force balance with the <span class="hlt">plasma</span> pressures using a 3D magnetic field model [Zaharia, 2008]. The force-balanced magnetic field configuration shows that Bz decreases in the near Earth region and increases in the tail due to an increasing perpendicular current peaking at the earthward edge of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. The current peak moves towards the Earth as energy loading increases, indicating earthward penetrating of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. Meanwhile, positive dBz/dz is found to develop late in the growth phase, but a Bz minimum at the equator does not form, unlike the prediction by Saito et al. [2010]. The perpendicular current peaks off the equator plane and its peak moves towards the equatorial plane as the growth phase evolves, indicating the thinning of current <span class="hlt">sheet</span>. In addition, there are typical Region-1 FACs around 12 to 20 RE at the beginning of substorm growth phase and they gradually evolve to Region-2 FACs in the late growth phase with their earthward boundary moving to smaller r. The model magnetic fields agree quantitatively well with observed fields. The magnetic field is substantially more stretched under higher PSW while the dependence on sunspot number is non-linear and less substantial. The excellent agreements between the model results and observations give us confidence that the realistic model can be used at the first time to understand the pressure and magnetic field changes observed during a substorm event by providing accurate evaluations of the effects of energy loading and PSW, as well as the temporal and spatial effects along a spacecraft trajectory. By applying our modeling to a substorm event, we found that the equatorward moving of proton aurora during the growth phase is mainly due to continuous stretching of magnetic field lines, and the ballooning instability is more favorable at late growth phase around midnight tail where there is a locali</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSM11B..06S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSM11B..06S"><span id="translatedtitle">Thick Bifurcated Current <span class="hlt">Sheet</span> in the Near-Earth Tail <span class="hlt">Plasma</span> <span class="hlt">Sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saito, M.</p> <p>2014-12-01</p> <p>The bifurcated structure of the current <span class="hlt">sheet</span> in the mid tail (X~-20 RE) has been reported in several in-situ observational studies. The presented study examines a spatial distribution of current densities that statistically infer a thick bifurcated current <span class="hlt">sheet</span> as a typical structure in the near-Earth tail (X=-8 to -12 RE). The current density is evaluated by using any two of THEMIS spacecraft measurements when certain conditions, such as spacecraft separation and orientation, are strictly met. A survey from 2007 to 2013 results in approximately 3000 current densities, which made it possible to study north-south profile of the current <span class="hlt">sheet</span>. The peak of the current density is often found 0.5 RE to 1 RE off the magnetic equator, while the median half-thickness of the current <span class="hlt">sheet</span> is approximately 3 RE. These indicate that the current <span class="hlt">sheet</span> is thick and bifurcated on average. Presumably, owing to this non-uniform profile, local current densities sometimes become very intense. The intense current density preferentially occurs during growth phase and expansion phase of substorms, but also occur in quiet time. The intense current densities are found to be independent from the solar wind dynamic pressure. It is concluded that the intense current density is not caused by the compression of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. Other mechanisms need to be suggested to fully understand the structure and the evolution of the current <span class="hlt">sheet</span> in the near-Earth tail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EPJD...54..271P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EPJD...54..271P"><span id="translatedtitle">ADBD <span class="hlt">plasma</span> surface treatment of PES fabric <span class="hlt">sheets</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pchal, J.; Klenko, Y.</p> <p>2009-08-01</p> <p><span class="hlt">Plasma</span> treatment of textile fabrics is investigated as an alternative to the environmentally hazardous wet chemical fabric treatment and pretreatment processes. <span class="hlt">Plasma</span> treatment usually results in modification of the uppermost atomic layers of a material surface and leaves the bulk characteristics unaffected. It may result in desirable surface modifications, e.g. surface etching, surface activation, cross-linking, chain scission and oxidation. Presented paper contains results of the applicability study of the atmospheric pressure dielectric discharge (ADBD), i.e. dielectric barrier discharge sustaining in air at atmospheric pressure and ambient temperature for synchronous treatment of several <span class="hlt">sheets</span> of fabric. For tests <span class="hlt">sheets</span> of polyester fabric were used. Effectivity of the modification process was determined with hydrophilicity measurements evaluated by means of the drop test. Hydrophilicity of individual <span class="hlt">sheets</span> of fabric has distinctly increased after <span class="hlt">plasma</span> treatment. <span class="hlt">Plasma</span> induced surface changes of textiles were also proven by identification of new functional groups at the modified polyester fabric surface. Existence of new functional groups was detected by ESCA scans. For verification of surface changes we also applied high-resolution microphotography. It has shown distinct variation of the textile surface after <span class="hlt">plasma</span> treatment. Important aspect for practical application of the <span class="hlt">plasma</span> treatment is the modification effect time-stability, i.e. time stability of acquired surface changes of the fabric. The recovery of hydrophobicity was fastest in first days after treatment, later gradually diminished until reached almost original untreated state.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhPl...22j2110J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhPl...22j2110J"><span id="translatedtitle">Evolution of <span class="hlt">electron</span> current <span class="hlt">sheets</span> in collisionless magnetic reconnection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jain, Neeraj; Sharma, A. Surjalal</p> <p>2015-10-01</p> <p>An <span class="hlt">electron</span> current <span class="hlt">sheet</span> embedded in an ion scale current <span class="hlt">sheet</span> is an inherent feature of collisionless magnetic reconnection. Such thin <span class="hlt">electron</span> current <span class="hlt">sheets</span> are unstable to tearing mode and produce secondary magnetic islands modulating the reconnection rate. In this work, 2-D evolution of tearing mode at multiple reconnection sites in an <span class="hlt">electron</span> current <span class="hlt">sheet</span> is studied using <span class="hlt">electron</span>-magnetohydrodynamic (EMHD) model. It is shown that growth of the perturbations can make reconnection impulsive by suddenly enhancing the reconnection rate and also forms new structures in the presence of multiple reconnection sites, one of which is dominant and others are secondary. The rise of the reconnection rate to a peak value and the time to reach the peak value due to tearing instability are similar to those observed in particle-in-cell simulations for similar thicknesses of the <span class="hlt">electron</span> current <span class="hlt">sheet</span>. The peak reconnection rate scales as 0.05 / ? 1.15 , where ? is half thickness of the current <span class="hlt">sheet</span>. Interactions of <span class="hlt">electron</span> outflows from the dominant and secondary sites form a double vortex <span class="hlt">sheet</span> inside the magnetic island between the two sites. <span class="hlt">Electron</span> Kelvin-Helmholtz instability in the double vortex <span class="hlt">sheet</span> produces secondary vortices and consequently turbulence inside the magnetic island. Interaction of outflow from the dominant site and inflows to the adjacent secondary sites launches whistler waves which propagate from the secondary sites into the upstream region at Storey angle with the background magnetic field. Due to the wave propagation, the out-of-plane magnetic field has a nested structure of quadrupoles of opposite polarities. A numerical linear eigen value analysis of the EMHD tearing mode, valid for current <span class="hlt">sheet</span> half-thicknesses ranging from ? < d e = c / ? p e (strong <span class="hlt">electron</span> inertia) to ? > d e (weak <span class="hlt">electron</span> inertia), is presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..DPPUO6009K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..DPPUO6009K"><span id="translatedtitle">Preliminary characterization of a laser-generated <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Keiter, Paul; Trantham, Matt; Malamud, Guy; Klein, Sallee; Fein, Jeff; Davis, Josh; Gillespe, Robb; Drake, R. Paul</p> <p>2013-10-01</p> <p>A reverse shock is a shock formed when a freely expanding <span class="hlt">plasma</span> encounters an obstacle. Reverse shocks can be generated by a blast wave propagating through a medium. They can also be found in binary star systems where the flowing gas from a companion star interacts with the accretion disk of the primary star. Previous experiments [Krauland et al. 2013] created a reverse radiative shock, in which, flowing <span class="hlt">plasma</span>, representing the flowing <span class="hlt">plasma</span> from the secondary star, interacted with a stationary object, which represented the accretion disk. Future experiments will replace the stationary object with a flowing <span class="hlt">plasma</span> to represent the accretion disk and create a reverse radiative shock from the interaction of two flowing <span class="hlt">plasmas</span>. Recent experiments created a flowing <span class="hlt">sheet</span> of <span class="hlt">plasma</span>. We will present the experimental results, including measurements of the spatial extent, density and velocity of the flowing <span class="hlt">plasma</span> <span class="hlt">sheet</span>. We will also discuss the implications for future experiments. This work is funded by the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory <span class="hlt">Plasmas</span>, grant number DE-FG52-09NA29548.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhPl...21c2113T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhPl...21c2113T"><span id="translatedtitle">Kinetic theory of the <span class="hlt">electron</span> bounce instability in two dimensional current <span class="hlt">sheets</span>-Full electromagnetic treatment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tur, A.; Fruit, G.; Louarn, P.; Yanovsky, V.</p> <p>2014-03-01</p> <p>In the general context of understanding the possible destabilization of a current <span class="hlt">sheet</span> with applications to magnetospheric substorms or solar flares, a kinetic model is proposed for studying the resonant interaction between electromagnetic fluctuations and trapped bouncing <span class="hlt">electrons</span> in a 2D current <span class="hlt">sheet</span>. Tur et al. [A. Tur et al., Phys. <span class="hlt">Plasmas</span> 17, 102905 (2010)] and Fruit et al. [G. Fruit et al., Phys. <span class="hlt">Plasmas</span> 20, 022113 (2013)] already used this model to investigate the possibilities of electrostatic instabilities. Here, the model is completed for full electromagnetic perturbations. Starting with a modified Harris <span class="hlt">sheet</span> as equilibrium state, the linearized gyrokinetic Vlasov equation is solved for electromagnetic fluctuations with period of the order of the <span class="hlt">electron</span> bounce period. The particle motion is restricted to its first Fourier component along the magnetic field and this allows the complete time integration of the non local perturbed distribution functions. The dispersion relation for electromagnetic modes is finally obtained through the quasineutrality condition and the Ampere's law for the current density. It is found that for mildly strechted current, undamped modes oscillate at typical <span class="hlt">electron</span> bounce frequency with wavelength of the order of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> half thickness. As the stretching of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> becomes more intense, the frequency of these normal modes decreases and beyond a certain threshold in ? = Bz/Blobes, the mode becomes explosive with typical growth rate of a few tens of seconds. The free energy contained in the bouncing motion of the <span class="hlt">electrons</span> may trigger an electromagnetic instability able to disrupt the cross-tail current in a few seconds. This new instability-electromagnetic <span class="hlt">electron</span>-bounce instability-may explain fast and global scale destabilization of current <span class="hlt">sheets</span> as required to describe substorm phenomena.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22251923','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22251923"><span id="translatedtitle">Kinetic theory of the <span class="hlt">electron</span> bounce instability in two dimensional current <span class="hlt">sheets</span>Full electromagnetic treatment</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tur, A.; Fruit, G.; Louarn, P.</p> <p>2014-03-15</p> <p>In the general context of understanding the possible destabilization of a current <span class="hlt">sheet</span> with applications to magnetospheric substorms or solar flares, a kinetic model is proposed for studying the resonant interaction between electromagnetic fluctuations and trapped bouncing <span class="hlt">electrons</span> in a 2D current <span class="hlt">sheet</span>. Tur et al. [A. Tur et al., Phys. <span class="hlt">Plasmas</span> 17, 102905 (2010)] and Fruit et al. [G. Fruit et al., Phys. <span class="hlt">Plasmas</span> 20, 022113 (2013)] already used this model to investigate the possibilities of electrostatic instabilities. Here, the model is completed for full electromagnetic perturbations. Starting with a modified Harris <span class="hlt">sheet</span> as equilibrium state, the linearized gyrokinetic Vlasov equation is solved for electromagnetic fluctuations with period of the order of the <span class="hlt">electron</span> bounce period. The particle motion is restricted to its first Fourier component along the magnetic field and this allows the complete time integration of the non local perturbed distribution functions. The dispersion relation for electromagnetic modes is finally obtained through the quasineutrality condition and the Ampere's law for the current density. It is found that for mildly strechted current, undamped modes oscillate at typical <span class="hlt">electron</span> bounce frequency with wavelength of the order of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> half thickness. As the stretching of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> becomes more intense, the frequency of these normal modes decreases and beyond a certain threshold in ??=?B{sub z}/B{sub lobes}, the mode becomes explosive with typical growth rate of a few tens of seconds. The free energy contained in the bouncing motion of the <span class="hlt">electrons</span> may trigger an electromagnetic instability able to disrupt the cross-tail current in a few seconds. This new instabilityelectromagnetic <span class="hlt">electron</span>-bounce instabilitymay explain fast and global scale destabilization of current <span class="hlt">sheets</span> as required to describe substorm phenomena.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JGRA..118.6319X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JGRA..118.6319X"><span id="translatedtitle">Auroral wave structures and ballooning instabilities in the <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xing, Xiaoyan; Liang, Jun; Spanswick, Emma; Lyons, Larry; Angelopoulos, Vassilis</p> <p>2013-10-01</p> <p>wavelike structures extended in the east-west direction along preexisting arcs are often observed to precede the auroral poleward expansions initiated along that arc. These wave structures are suggested to be the manifestation of ballooning/interchange instabilities in the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> that may play crucial roles in leading to substorm expansion. The triggering and the development of the ballooning instability in the MHD regime can be evaluated with theory and numerical simulations; however, observations have never shown how these instabilities are initiated in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. In order to examine the instability triggering, we take advantage of the THEMIS ground all-sky-imagers and NORSTAR-NASCAM multiwavelength imagers together with a multi-spacecraft conjunction to identify the auroral wave structures and to examine the dynamics in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. We show in a case study that the MHD ballooning instability criterion is violated near X = -11 RE in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> starting about 1.5 min prior to the initiation of the auroral wave structures. The estimated Alfvnic transit time is slightly larger than 1 min, indicating that the observed auroral signatures are correlated with the ballooning instability developing in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and propagating to the ionosphere along field lines. Magnetic field wavelet analysis shows the initiation of the perpendicular disturbances between 0.01 and 0.02 Hz correlated with the calculated onset of the instability perturbations at the same location, supporting the identification of the localized ballooning instability. At the more tailward region of X ~ -13 RE, enhanced earthward transport toward the unstable region are observed several minutes prior to the instability initiation, which may have modified the pressure spatial distribution and magnetic field topology in the near-Earth region, leading to the violation of the instability criterion. The further development of the instability may play a crucial role for the aurora explosive expansion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5305529','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5305529"><span id="translatedtitle">Nonadiabatic heating of the central <span class="hlt">plasma</span> <span class="hlt">sheet</span> at substorm onset</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Huang, C.Y.; Frank, L.A. ); Rostoker, G. ); Fennell, J. ); Mitchell, D.G. )</p> <p>1992-02-01</p> <p>Heating events in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer and central <span class="hlt">plasma</span> <span class="hlt">sheet</span> are found to occur at the onset of expansive phase activity. The main effect is a dramatic increase in <span class="hlt">plasma</span> temperature, coincident with a partial dipolarization of the magnetic field. Fluxes of energetic particles increase without dispersion during these events which occur at all radial distances up to 23 R{sub E}, the apogee of the ISEIE spacecraft. A major difference between these heating events and those observed at geosynchronous distances lies in the heating mechanism which is nonadiabatic beyond 10 R{sub E} but may be adiabatic closer to Earth. The energy required to account for the increase in <span class="hlt">plasma</span> thermal energy is comparable with that required for Joule heating of the ionosphere. The <span class="hlt">plasma</span> <span class="hlt">sheet</span> must be considered as a major sink in the energy balance of substorm. The authors estimate lobe magnetic pressures during these events. Changes in lobe pressure are generally not correlated with onsets or intensifications of expansive phase activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040086547','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040086547"><span id="translatedtitle">Substorm Evolution in the Near-Earth <span class="hlt">Plasma</span> <span class="hlt">Sheet</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Erickson, Gary M.</p> <p>2004-01-01</p> <p>This grant represented one-year, phase-out funding for the project of the same name (NAG5-9110 to Boston University) to determine precursors and signatures of local substorm onset and how they evolve in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> using the Geotail near-Earth database. We report here on two accomplishments: (1) Completion of an examination of <span class="hlt">plasma</span> velocity signature at times of local onsets in the current disruption (CD) region. (2) Initial investigation into quantification of near-Earth flux-tube contents of injected <span class="hlt">plasma</span> at times of substorm injections.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19890000538&hterms=galvanometer&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dgalvanometer','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19890000538&hterms=galvanometer&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dgalvanometer"><span id="translatedtitle"><span class="hlt">Electronic</span> Rotator For <span class="hlt">Sheet</span> Of Laser Light</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Franke, John M.; Rhodes, David B.; Leighty, Bradley D.; Jones, Stephen B.</p> <p>1989-01-01</p> <p>Primary flow-visualization system in Basic Aerodynamic Research Tunnel (BART) at NASA Langley Research Center is <span class="hlt">sheet</span> of laser light generated by 5-W argon-ion laser and two-axis mirror galvanometer scanner. Generates single and multiple <span class="hlt">sheets</span> of light, which remain stationary or driven to sweep out volume. Sine/cosine potentiometer used to orient two galvanometer/mirror devices simultaneously and yields desired result at reasonable cost and incorporated into prototype in 1 day.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840027172','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840027172"><span id="translatedtitle"><span class="hlt">Plasma</span> <span class="hlt">electron</span> analysis: Voyager <span class="hlt">plasma</span> science experiment</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sittler, E. C., Jr.</p> <p>1983-01-01</p> <p>The <span class="hlt">Plasma</span> Science Experiment (PLS) on the Voyager spacecraft provide data on the <span class="hlt">plasma</span> ions and <span class="hlt">electrons</span> in the interplanetary medium and the magnetospheres of the giant planets Jupiter and Saturn. A description of the analysis used to obtain <span class="hlt">electron</span> parameters (density, temperature, etc.) from the <span class="hlt">plasma</span> science experiment PLS <span class="hlt">electron</span> measurements which cover the energy range from 10 eV to 5950 eV is presented. The <span class="hlt">electron</span> sensor (D cup) and its transmission characteristics are described. A derivation of the fundamental analytical expression of the reduced distribution function F(e) is given. The <span class="hlt">electron</span> distribution function F(e), used in the moment integrations, can be derived from F(e). Positive ions produce a correction current (ion feedthrough) to the measured <span class="hlt">electron</span> current, which can be important to the measurements of the suprathermal <span class="hlt">electron</span> component. In the case of Saturn, this correction current, which can either add to or subtract from the measured <span class="hlt">electron</span> current, is less than 20% of the measured signal at all times. Comments about the corrections introduced by spacecraft charging to the Saturn encounter data, which can be important in regions of high density and shadow when the spacecraft can become negatively charged are introduced.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950029531&hterms=Plasma+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DPlasma%2Benergy','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950029531&hterms=Plasma+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DPlasma%2Benergy"><span id="translatedtitle">Contribution of low-energy ionospheric protons to the <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Delcourt, D. C.; Moore, T. E.; Chappell, C. R.</p> <p>1994-01-01</p> <p>The magnetospheric transport of low-energy ionospheric ions is examined by means of three-dimensional particle codes. Emphasis is placed on the behavior of polar wind and cleft originating protons. It is demonstrated that, via nonadiabatic motion inside the neutral <span class="hlt">sheet</span>, these ions can significantly contribute to the populations of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. The importance of this contribution is found to depend critically upon the dynamics of particles originating from the highest latitudes, as these possibly have access to the distant tail. Hence it is shown that polar wind H(+) expelled into the magnetosphere at very low energies (in the <span class="hlt">electron</span> volt range) preferentially feed the <span class="hlt">plasma</span> <span class="hlt">sheet</span> during quiet times, experiencing accelerations up to several kiloelectron volts upon return into the inner magnetosphere. In contrast, during disturbed times, the intensifying magnetospheric convection confines this population to low L shells where it travels in a nearly adiabatic manner. As for the protons originating from the cleft fountain, the simulations reveal that they can be transported up to the vicinity of the distant neutral line in the nightside sector. Via interaction with the neutral <span class="hlt">sheet</span>, these ionospheric ions are rapidly raised to the characteristic <span class="hlt">plasma</span> <span class="hlt">sheet</span> energy range. The density levels contributed by these populations are quite substantial when compared to those measured in situ. These simulations establish an active role of low-energy ionospheric ions in the overall magnetospheric dynamics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ApSS..258.8209Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ApSS..258.8209Z"><span id="translatedtitle">The effect of <span class="hlt">plasma</span> modification on the <span class="hlt">sheet</span> resistance of nylon fabrics coated with carbon nanotubes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Wei; Johnson, Les; Silva, S. Ravi P.; Lei, M. K.</p> <p>2012-08-01</p> <p>Low-pressure oxygen and argon <span class="hlt">plasmas</span> were used to pre-treat nylon fabrics, and the modified fabrics, together with the raw fabrics, were subsequently coated with single walled carbon nanotubes (SWCNTs) by a dip-drying process. Scanning <span class="hlt">electron</span> microscopy (SEM) and Raman spectroscopy analyses indicated the attachment of SWCNTs onto nylon fabrics. After the coating with SWCNTs, the <span class="hlt">plasma</span> modified fabrics exhibited <span class="hlt">sheet</span> resistance of as low as 2.0 kΩ/sq. with respect to 4.9 kΩ/sq. of the raw fabrics, presumably owing to the increase of fibre surface roughness incurred by the <span class="hlt">plasma</span> modification, which is evidenced by SEM analyses. Fourier transform infrared spectroscopy (FTIR) analysis indicates the incorporation of oxygen functionalities on fibre surfaces in the <span class="hlt">plasma</span> modification. This is responsible for the variation of the electrical conductance of SWCNT-coated fabrics with the type of <span class="hlt">plasma</span> and the duration of <span class="hlt">plasma</span> ablation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUSM..SM52A11F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUSM..SM52A11F"><span id="translatedtitle">Auroral dynamics in relation to <span class="hlt">plasma</span> <span class="hlt">sheet</span> particle injections during substorm expansions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Farrugia, C. J.; Sandholt, P.; Lester, M.; Cowley, S. W.; Denig, W. F.; Lybekk, B.; Trondsen, E.</p> <p>2001-05-01</p> <p>We present multipoint observations of two substorms, focussing on the multi-stage latitudinal expansions of the aurora with intensifications of its poleward boundary, and relating these to <span class="hlt">plasma</span> <span class="hlt">sheet</span> dynamics. The observations were made by meridian scanning photometers and an all-sky camera at Ny Alesund, Svalbard, situated at 76o magnetic latitude, magnetometers of the IMAGE array in Svalbard-Scandinavia, the HYDRA instrument on the Polar spacecraft, crossing the inner edge of the equatorial <span class="hlt">plasma</span> <span class="hlt">sheet</span>, particle detectors on the DMSP F13 and F14 spacecraft traversing the ionospheric projection of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, and the CUTLASS Finland HF radar. The high-latitude branch of the aurora (at ~75o--78o MLAT) was subject to short-lived ( ~1-2 min) intensifications, so-called ``poleward boundary intensifications" (PBIs). Subsequent to each of these brightenings auroral forms travelled equatorward at an estimated speed of 1.0--1.5 km s-1. The BPIs are related on a one-to-one basis with injections of <span class="hlt">electrons</span> in the 5-20 keV energy range at the inner edge of the equatorial <span class="hlt">plasma</span> <span class="hlt">sheet</span>, delayed by ~5 min.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6864804','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6864804"><span id="translatedtitle">On the nature of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hones, E.W. Jr. Los Alamos National Lab., NM )</p> <p>1990-01-01</p> <p>The regions of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> adjacent to the north and south lobes of the magnetotail have been described by many experimenters as locations of beams of energetic ions and fast-moving <span class="hlt">plasma</span> directed primarily earthward and tailward along magnetic field lines. Measurements taken as satellites passed through one or the other of these boundary layers have frequently revealed near-earth mirroring of ions and a vertical segregation of velocities of both earthward-moving and mirroring ions with the fastest ions being found nearest the lobe-<span class="hlt">plasma</span> <span class="hlt">sheet</span> interface. These are features expected for particles from a distant tail source {bar E} {times} {bar B} drifting in a dawn-to-dusk electric field and are consistent with the source being a magnetic reconnection region. The <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layers are thus understood as separatrix layers, bounded at their lobeward surfaces by the separatrices from the distant neutral line. This paper will review the observations that support this interpretation. 10 refs., 7 figs.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_5 --> <div id="page_6" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="101"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.4487Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.4487Z"><span id="translatedtitle">Earthward and tailward flows in the <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, L. Q.; Wang, J. Y.; Baumjohann, W.; Rme, H.; Dunlop, M. W.</p> <p>2015-06-01</p> <p>Utilizing C3/Cluster satellite observations from the year of 2001 to 2006, we investigated the earthward flow (EF) and tailward flow (TF) at Bz > 0 in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. We found that the EF and the TF have similar spatial distributions. Both characteristics are independent of the distance beyond 14 RE. Both flows are deflected while closer to the Earth. Statistical results further showed that the EF/TF occur in the central <span class="hlt">plasma</span> <span class="hlt">sheet</span> as well as the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer and can be observed during quiet times and periods of geomagnetic activity. A typical event reveals that the EF and the TF have different <span class="hlt">plasma</span> population. A transition region (TR) can be formed at the interface between the EF and TF. Very significant duskward components appeared in bulk velocities for both populations. It appears that the vortical-like structure can be formed near the TR. The magnetic field within the TR is twisted and strongly fluctuates. No clear magnetic flux pileups are observed inside the TR.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMSM31B1718I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMSM31B1718I"><span id="translatedtitle">Spatial Distribution of Dense <span class="hlt">Plasma</span> in the Near-Earth <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> and its Transport Into the Inner Magnetosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Izutsu, T.; Nishino, M. N.; Fujimoto, M.; Lavraud, B.; Hasegawa, H.; Angelopoulos, V.; McFadden, J. P.; Larson, D.; Auster, U.; Saito, Y.; Thomsen, M. F.</p> <p>2008-12-01</p> <p>We investigate the cold-dense <span class="hlt">plasma</span> <span class="hlt">sheet</span> (CDPS) on November 12 and 13, 2007 by using THEMIS, Geotail, and LANL satellite. During the last extend period of northward IMF, 2-component CDPS in the duskside <span class="hlt">plasma</span> <span class="hlt">sheet</span> (PS), single component CDPS in the dawnside PS, and hot-dense ions (HDIs) at the inner edge of the PS on the dawnside were observed by Geotail, THC, and THA simultaneously. Then, super-dense <span class="hlt">plasma</span> <span class="hlt">sheet</span> (SDPS) was detected near the midnight region at geosynchronous orbit (GEO) (i) 1 hour after the southward turning of the IMF and (ii) at the rapid enhancement of the solar wind density (4 hours after (i)). Focusing on (i), duskward moving HDIs and earthward fast flow were encountered by Geotail in the pre-midnight PS. The appearance of SDPS and energetic <span class="hlt">electrons</span> was in good association with this fast flow. We suggest that HDIs on the dawnside moved to the pre-midnight PS and they were pushed into GEO by the fast flow. After both observations of SDPS, the dense <span class="hlt">plasma</span> was not seen on the dawnside where THA had detected HDIs (X < ~-5 Re), while it existed earthward of the region. Although these periods were front parts of corotating interaction region (CIR), geomagnetic activity was very weak. We discuss the transport mechanism and the geoeffectiveness of the dense <span class="hlt">plasma</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.1022L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.1022L"><span id="translatedtitle">Acceleration of O+ from the cusp to the <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liao, J.; Kistler, L. M.; Mouikis, C. G.; Klecker, B.; Dandouras, I.</p> <p>2015-02-01</p> <p>Heavy ions from the ionosphere that are accelerated in the cusp/cleft have been identified as a direct source for the hot <span class="hlt">plasma</span> in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. However, the details of the acceleration and transport that transforms the originally cold ions into the hot <span class="hlt">plasma</span> <span class="hlt">sheet</span> population are not fully understood. The polar orbit of the Cluster satellites covers the main transport path of the O+ from the cusp to the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, so Cluster is ideal for tracking its velocity changes. However, because the cusp outflow is dispersed according to its velocity as it is transported to the tail, due to the velocity filter effect, the observed changes in beam velocity over the Cluster orbit may simply be the result of the spacecraft accessing different spatial regions and not necessarily evidence of acceleration. Using the Cluster Ion Spectrometry/Composition Distribution Function instrument onboard Cluster, we compare the distribution function of streaming O+ in the tail lobes with the initial distribution function observed over the cusp and reveal that the observations of energetic streaming O+ in the lobes around -20 RE are predominantly due to the velocity filter effect during nonstorm times. During storm times, the cusp distribution is further accelerated. In the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer, however, the average O+ distribution function is above the upper range of the outflow distributions at the same velocity during both storm and nonstorm times, indicating that acceleration has taken place. Some of the velocity increase is in the direction perpendicular to the magnetic field, indicating that the E B velocity is enhanced. However, there is also an increase in the parallel direction, which could be due to nonadiabatic acceleration at the boundary or wave heating.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PSST...25a5013T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PSST...25a5013T"><span id="translatedtitle">On the <span class="hlt">plasma</span>-based growth of ‘flowing’ graphene <span class="hlt">sheets</span> at atmospheric pressure conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsyganov, D.; Bundaleska, N.; Tatarova, E.; Dias, A.; Henriques, J.; Rego, A.; Ferraria, A.; Abrashev, M. V.; Dias, F. M.; Luhrs, C. C.; Phillips, J.</p> <p>2016-02-01</p> <p>A theoretical and experimental study on atmospheric pressure microwave <span class="hlt">plasma</span>-based assembly of free standing graphene <span class="hlt">sheets</span> is presented. The synthesis method is based on introducing a carbon-containing precursor (C2H5OH) through a microwave (2.45 GHz) argon <span class="hlt">plasma</span> environment, where decomposition of ethanol molecules takes place and carbon atoms and molecules are created and then converted into solid carbon nuclei in the ‘colder’ nucleation zones. A theoretical model previously developed has been further updated and refined to map the particle and thermal fluxes in the <span class="hlt">plasma</span> reactor. Considering the nucleation process as a delicate interplay between thermodynamic and kinetic factors, the model is based on a set of non-linear differential equations describing <span class="hlt">plasma</span> thermodynamics and chemical kinetics. The model predictions were validated by experimental results. Optical emission spectroscopy was applied to detect the <span class="hlt">plasma</span> emission related to carbon species from the ‘hot’ <span class="hlt">plasma</span> zone. Raman spectroscopy, scanning <span class="hlt">electron</span> microscopy (SEM), and x-ray photoelectron spectroscopy (XPS) techniques have been applied to analyze the synthesized nanostructures. The microstructural features of the solid carbon nuclei collected from the colder zones of <span class="hlt">plasma</span> reactor vary according to their location. A part of the solid carbon was deposited on the discharge tube wall. The solid assembled from the main stream, which was gradually withdrawn from the hot <span class="hlt">plasma</span> region in the outlet <span class="hlt">plasma</span> stream directed to a filter, was composed by ‘flowing’ graphene <span class="hlt">sheets</span>. The influence of additional hydrogen, Ar flow rate and microwave power on the concentration of obtained stable species and carbon‑dicarbon was evaluated. The ratio of sp3/sp2 carbons in graphene <span class="hlt">sheets</span> is presented. A correlation between changes in C2 and C number densities and sp3/sp2 ratio was found.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910036461&hterms=Romero&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DRomero','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910036461&hterms=Romero&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DRomero"><span id="translatedtitle">Equilibrium structure of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer-lobe interface</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Romero, H.; Ganguli, G.; Palmadesso, P.; Dusenbery, P. B.</p> <p>1990-01-01</p> <p>Observations are presented which show that <span class="hlt">plasma</span> parameters vary on a scale length smaller than the ion gyroradius at the interface between the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer and the lobe. The Vlasov equation is used to investigate the properties of such a boundary layer. The existence, at the interface, of a density gradient whose scale length is smaller than the ion gyroradius implies that an electrostatic potential is established in order to maintain quasi-neutrality. Strongly sheared (scale lengths smaller than the ion gyroradius) perpendicular and parallel (to the ambient magnetic field) <span class="hlt">electron</span> flows develop whose peak velocities are on the order of the <span class="hlt">electron</span> thermal speed and which carry a net current. The free energy of the sheared flows can give rise to a broadband spectrum of electrostatic instabilities starting near the <span class="hlt">electron</span> <span class="hlt">plasma</span> frequency and extending below the lower hybrid frequency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22053894','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22053894"><span id="translatedtitle"><span class="hlt">Electron</span> cyclotron resonance <span class="hlt">plasma</span> photos</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Racz, R.; Palinkas, J.; Biri, S.</p> <p>2010-02-15</p> <p>In order to observe and study systematically the <span class="hlt">plasma</span> of <span class="hlt">electron</span> cyclotron resonance (ECR) ion sources (ECRIS) we made a high number of high-resolution visible light <span class="hlt">plasma</span> photos and movies in the ATOMKI ECRIS Laboratory. This required building the ECR ion source into an open ECR <span class="hlt">plasma</span> device, temporarily. An 8MP digital camera was used to record photos of <span class="hlt">plasmas</span> made from Ne, Ar, and Kr gases and from their mixtures. We studied and recorded the effect of ion source setting parameters (gas pressure, gas composition, magnetic field, and microwave power) to the shape, color, and structure of the <span class="hlt">plasma</span>. The analysis of the photo series gave us many qualitative and numerous valuable physical information on the nature of ECR <span class="hlt">plasmas</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/14728558','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/14728558"><span id="translatedtitle">Task centered visualization of <span class="hlt">Electronic</span> Medical Record flow <span class="hlt">sheet</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xie, Zhong; Gregg, Peggy; Zhang, Jiajie</p> <p>2003-01-01</p> <p>Usability problem of <span class="hlt">Electronic</span> Medical Record (EMR) systems is a major hurdle for their acceptance. In this study we used the methodology of Human-Centered Distributed Information Design (HCDID) to compare and evaluate Flow <span class="hlt">Sheet</span> module of two commercial EMR systems. After which we tried to develop usable interface of a flow <span class="hlt">sheet</span> using visualization, focusing on task-representation mapping during design and development. PMID:14728558</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRA..119.8318W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRA..119.8318W"><span id="translatedtitle">Interchange motion as a transport mechanism for formation of cold-dense <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Chih-Ping; Gkioulidou, Matina; Lyons, Larry R.; Xing, Xiaoyan; Wolf, Richard A.</p> <p>2014-10-01</p> <p>To evaluate whether interchange motion can provide the transport for the formation of the cold-dense <span class="hlt">plasma</span> <span class="hlt">sheet</span> in the near-Earth region, we present an event of cold-dense <span class="hlt">plasma</span> <span class="hlt">sheet</span> observed by five THEMIS probes after the interplanetary magnetic field turned northward, as well as their comparisons with the simulation results from the Rice Convection Model (RCM) combined with a modified Dungey force-balanced magnetic field solver. The observations of cold-dense <span class="hlt">plasma</span> at different locations show quite different characteristics: (1) closer to the flank, the appearance is more periodic and exhibits larger fluctuations in <span class="hlt">plasma</span> moments and magnetic field; (2) further away from the flank, the cold <span class="hlt">plasma</span> appears later; (3) in the mixture with the cold <span class="hlt">plasma</span>, the decrease in high-energy particle fluxes becomes less significant further away from the flank; (4) there is energy-dispersion in the cold particles at some locations; and (5) near the magnetopause, the fluctuations have the characteristics of the Kelvin-Helmholtz (K-H) vortices and the colder-denser <span class="hlt">plasma</span> is likely to have lower entropy. In the RCM simulations, lower entropy <span class="hlt">plasma</span> consisting of colder-denser ions and <span class="hlt">electrons</span> was periodically released locally at the outer boundary to represent the <span class="hlt">plasma</span> created within a K-H vortex. This lower entropy perturbation is interchange unstable and the resulting interchange motion through the magnetosphere-ionosphere coupling pushes the colder-denser <span class="hlt">plasma</span> radially inward. The simulated particle energy spectrums at different locations qualitatively reproduce the observations, strongly suggesting that the seemingly different characteristics of cold-dense <span class="hlt">plasma</span> observed by different probes are all a result of the same interchange-related transport mechanism.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1989JGR....94.6995F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1989JGR....94.6995F"><span id="translatedtitle"><span class="hlt">Electron</span> velocity distributions and <span class="hlt">plasma</span> waves associated with the injection of an <span class="hlt">electron</span> beam into the ionosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Frank, L. A.; Paterson, W. R.; Kurth, W. S.; Ashour-Abdalla, M.; Schriver, D.</p> <p>1989-06-01</p> <p>An <span class="hlt">electron</span> beam was injected into earth's ionosphere on August 1, 1985, during the flight of the Space Shuttle Challenger as part of the objectives of the Spacelab 2 mission. In the wake of the Space Shuttle a magnetically aligned <span class="hlt">sheet</span> of <span class="hlt">electrons</span> returning from the direction of propagation of the beam was detected with the free-flying <span class="hlt">Plasma</span> Diagnostics Package. The thickness of this <span class="hlt">sheet</span> of returning <span class="hlt">electrons</span> was about 20 m. Large intensifications of broadband electrostatic noise were also observed within this <span class="hlt">sheet</span> of <span class="hlt">electrons</span>. A numerical simulation of the interaction of the <span class="hlt">electron</span> beam with the ambient ionospheric <span class="hlt">plasmas</span> is employed to show that the <span class="hlt">electron</span> beam excites <span class="hlt">electron</span> <span class="hlt">plasma</span> oscillations and that it is possible for the ion acoustic instability to provide a returning flux of hot <span class="hlt">electrons</span> by means of quasi-linear diffusion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19890056327&hterms=INJECTION+BEAM&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DINJECTION%2BBEAM','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19890056327&hterms=INJECTION+BEAM&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DINJECTION%2BBEAM"><span id="translatedtitle"><span class="hlt">Electron</span> velocity distributions and <span class="hlt">plasma</span> waves associated with the injection of an <span class="hlt">electron</span> beam into the ionosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Frank, L. A.; Paterson, W. R.; Kurth, W. S.; Ashour-Abdalla, M.; Schriver, D.</p> <p>1989-01-01</p> <p>An <span class="hlt">electron</span> beam was injected into earth's ionosphere on August 1, 1985, during the flight of the Space Shuttle Challenger as part of the objectives of the Spacelab 2 mission. In the wake of the Space Shuttle a magnetically aligned <span class="hlt">sheet</span> of <span class="hlt">electrons</span> returning from the direction of propagation of the beam was detected with the free-flying <span class="hlt">Plasma</span> Diagnostics Package. The thickness of this <span class="hlt">sheet</span> of returning <span class="hlt">electrons</span> was about 20 m. Large intensifications of broadband electrostatic noise were also observed within this <span class="hlt">sheet</span> of <span class="hlt">electrons</span>. A numerical simulation of the interaction of the <span class="hlt">electron</span> beam with the ambient ionospheric <span class="hlt">plasmas</span> is employed to show that the <span class="hlt">electron</span> beam excites <span class="hlt">electron</span> <span class="hlt">plasma</span> oscillations and that it is possible for the ion acoustic instability to provide a returning flux of hot <span class="hlt">electrons</span> by means of quasi-linear diffusion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.6821D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.6821D"><span id="translatedtitle">MESSENGER Observations of Magnetic Flux Ropes in Mercury's <span class="hlt">Plasma</span> <span class="hlt">Sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>DiBraccio, Gina A.; Slavin, James A.; Imber, Suzanne M.; Gershman, Daniel J.; Raines, Jim M.; Boardsen, Scott A.; Anderson, Brian J.; Korth, Haje; Zurbuchen, Thomas H.; McNutt, Ralph L., Jr.; Solomon, Sean C.</p> <p>2014-05-01</p> <p>MESSENGER orbital observations provide a new opportunity to investigate magnetic reconnection in the cross-tail current <span class="hlt">sheet</span> of Mercury's magnetotail. Here we use measurements collected by the Magnetometer and Fast Imaging <span class="hlt">Plasma</span> Spectrometer (FIPS) during 'hot seasons,' when the orbital periapsis is on Mercury's dayside and MESSENGER crosses the <span class="hlt">plasma</span> <span class="hlt">sheet</span> at distances of ~1.5 to 3 RM (where RM is Mercury's radius, or 2440 km). These data frequently contain signatures of large-scale magnetic reconnection in the form of plasmoid-type magnetic flux ropes and southward magnetic fields in the post-plasmoid <span class="hlt">plasma</span> <span class="hlt">sheet</span>. In the cross-tail current <span class="hlt">sheet</span>, which separates the north and south lobes of the magnetotail, flux ropes are formed by reconnection at two or more X-lines and are then transported either toward or away from the planet by the Alfvénic flow emanating from the X-lines. Here we present a survey of 49 plasmoid-type flux ropes identified during seven MESSENGER 'hot seasons,' for which minimum variance analysis indicates that the spacecraft passed near the central axis of the structure. The locations of the selected flux ropes range between 1.7 and 2.8 RM down the tail from the center of the planet. With FIPS measurements, we determined an average proton density of 2.55 cm-3 in the adjacent <span class="hlt">plasma</span> <span class="hlt">sheet</span> surrounding the flux ropes, implying an Alfvén speed of ~450 km s-1. Under the assumption that the flux ropes are moving at the local Alfvén speed, we used the mean duration of 0.74 ± 0.15 s to calculate a typical diameter of ~0.14 RM, or ~340 km. We have modeled the plasmoids as force-free flux ropes in order to confirm this result. A superposed epoch analysis demonstrates that the magnetic structure of the flux ropes is similar to what is observed at Earth, but the timescales are 40 times faster at Mercury. The results of this flux rope survey indicate that intense magnetic reconnection occurs frequently in the cross-tail current layer of this small but extremely dynamic magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014GeoRL..41.8185C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014GeoRL..41.8185C"><span id="translatedtitle">Heating of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> by broadband electromagnetic waves</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chaston, C. C.; Bonnell, J. W.; Salem, C.</p> <p>2014-12-01</p> <p>We demonstrate that broadband low-frequency electromagnetic field fluctuations embedded within fast flows throughout the Earth's <span class="hlt">plasma</span> <span class="hlt">sheet</span> may drive significant ion heating. This heating is nearly entirely in the direction perpendicular to the background magnetic field and is estimated to occur at an average rate of ~1 eV/s with rates in excess of 10 eV/s within one standard deviation of the average value over all observed events. For an Earthward flow the total change in temperature along a flow path may exceed one keV and for "wave-rich" flows can be comparable to that expected due to conservation of the first adiabatic invariant. The consequent increase in <span class="hlt">plasma</span> pressure and flux tube entropy may lead to braking of inward motion and the suppression of <span class="hlt">plasma</span> interchange.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900063372&hterms=solution+plasma+process&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dsolution%2Bplasma%2Bprocess','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900063372&hterms=solution+plasma+process&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dsolution%2Bplasma%2Bprocess"><span id="translatedtitle">Resonant Alfven wave heating of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Harrold, B. G.; Goertz, C. K.; Smith, R. A.; Hansen, P. J.</p> <p>1990-01-01</p> <p>The exchange of energy between the <span class="hlt">plasma</span> mantle and the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer (PSBL) is examined with a one-dimensional magnetotail model. The energy exchange occurs via Poynting flux generated by the localized mode conversion of a surface wave to an Alfven wave. This Poynting flux propagates through the lobe and into the PSBL where it is absorbed by two processes. The first arises from a gradient in the <span class="hlt">plasma</span> beta causing a smooth absorption of Poynting flux. The second process results from the localized mode conversion of the decaying surface wave to an Alfven wave, causing a localized absorption of energy. A numerical solution of the linearized ideal MHD equations is obtained by assuming an adiabatic equation of state.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19720028786&hterms=escape+distance&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Descape%2Bdistance','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19720028786&hterms=escape+distance&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Descape%2Bdistance"><span id="translatedtitle"><span class="hlt">Plasma-sheet</span> ions at lunar distance preceding substorm onset.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Garrett, H. B.; Hill, T. W.; Fenner, M. A.</p> <p>1971-01-01</p> <p>During the partial lunar eclipse of August 17, 1970, four intense, transient bursts of kV-energy positive ions were detected at the lunar surface by the Rice University ALSEP Suprathermal Ion Detector Experiment. The eclipse happened to occur during a main-phase geomagnetic storm while the moon was within a few earth radii of the calculated position of the neutral <span class="hlt">sheet</span>. The two most intense ion bursts were each followed roughly one-half hour later by the sudden onset of a several thousand gamma polar magnetic substorm at the earth's surface. Two smaller ion enhancements were also followed by smaller magnetic disturbances. This observation is interpreted in terms of a downstream escape of <span class="hlt">plasma-sheet</span> particles associated with the substorm growth phase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19800024817','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19800024817"><span id="translatedtitle">Survey of the <span class="hlt">plasma</span> <span class="hlt">electron</span> environment of Jupiter: A view from Voyager</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Scudder, J. D.; Sittler, E. C., Jr.; Bridge, H. S.</p> <p>1980-01-01</p> <p>The <span class="hlt">plasma</span> environment within Jupiter's bow shock is considered in terms of the in situ, calibrated <span class="hlt">electron</span> <span class="hlt">plasma</span> measurements made between 10 eV and 5.95 keV by the Voyager <span class="hlt">plasma</span> science experiment (PLS). Measurements were analyzed and corrected for spacecraft potential variations; the data were reduced to nearly model independent macroscopic parameters of the local <span class="hlt">electron</span> density and temperature. It is tentatively concluded that the radial temperature profile within the <span class="hlt">plasma</span> <span class="hlt">sheet</span> is caused by the intermixing of two different <span class="hlt">electron</span> populations that probably have different temporal histories and spatial paths to their local observation. The cool <span class="hlt">plasma</span> source of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and spikes is probably the Io <span class="hlt">plasma</span> torus and arrives in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> as a result of flux tube interchange motions or other generalized transport which can be accomplished without diverting the <span class="hlt">plasma</span> from the centrifugal equator. The hot suprathermal populations in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> have most recently come from the sparse, hot mid-latitude "bath" of <span class="hlt">electrons</span> which were directly observed juxtaposed to the <span class="hlt">plasma</span> <span class="hlt">sheet</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.8210K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.8210K"><span id="translatedtitle">A new stationary analytical model of the heliospheric current <span class="hlt">sheet</span> and the <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kislov, Roman A.; Khabarova, Olga V.; Malova, Helmi V.</p> <p>2015-10-01</p> <p>We develop a single-fluid 2-D analytical model of the axially symmetric thin heliospheric current <span class="hlt">sheet</span> (HCS) embedded into the heliospheric <span class="hlt">plasma</span> <span class="hlt">sheet</span> (HPS). A HCS-HPS system has a shape of a relatively thin <span class="hlt">plasma</span> disk limited by separatrices that also represent current <span class="hlt">sheets</span>, which is in agreement with Ulysses observations in the aphelion, when it crossed the HCS perpendicular to its plane. Our model employs a differential rotation of the solar photosphere that leads to unipolar induction in the corona. Three components of the interplanetary magnetic field (IMF), the solar wind speed, and the thermal pressure are taken into account. Solar corona conditions and a HCS-HPS system state are tied by boundary conditions and the "frozen-in" equation. The model allows finding spatial distributions of the magnetic field, the speed within the HPS, and electric currents within the HCS. An angular <span class="hlt">plasma</span> speed is low within the HPS due to the angular momentum conservation (there is no significant corotation with the Sun), which is consistent with observations. We found that the HPS thickness L decreases with distance r, becoming a constant far from the Sun (L ~2.5 solar radii (R0) at 1 AU). Above the separatrices and at large heliocentric distances, the solar wind behavior obeys Parker's model, but the magnetic field spiral form may be different from Parker's one inside the HPS. At r ≤ 245 R0, the IMF spiral may undergo a turn simultaneously with a change of the poloidal current direction (from sunward to antisunward).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150007922','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150007922"><span id="translatedtitle">Ion Kinetic Properties in Mercury's Pre-Midnight <span class="hlt">Plasma</span> <span class="hlt">Sheet</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gershman, Daniel J.; Slavin, James A.; Raines, Jim M.; Zurbuchen, Thomas H.; Anderson, Brian J.; Korth, Haje; Baker, Daniel N.; Solomon, Sean C.</p> <p>2014-01-01</p> <p>With data from the Fast Imaging <span class="hlt">Plasma</span> Spectrometer sensor on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging spacecraft, we demonstrate that the average distributions for both solar wind and planetary ions in Mercury's pre-midnight <span class="hlt">plasma</span> <span class="hlt">sheet</span> are well-described by hot Maxwell-Boltzmann distributions. Temperatures and densities of the H(+)-dominated <span class="hlt">plasma</span> <span class="hlt">sheet</span>, in the ranges is approx. 1-10 cm(exp -3) and is approx. 5-30MK, respectively, maintain thermal pressures of is approx.1 nPa. The dominant planetary ion, Na(+), has number densities about 10% that of H(+). Solar wind ions retain near-solar-wind abundances with respect to H(+) and exhibit mass-proportional ion temperatures, indicative of a reconnection-dominated heating in the magnetosphere. Conversely, planetary ion species are accelerated to similar average energies greater by a factor of is approx. 1.5 than that of H(+). This energization is suggestive of acceleration in an electric potential, consistent with the presence of a strong centrifugal acceleration process in Mercury's magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5875513','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5875513"><span id="translatedtitle"><span class="hlt">Electron</span> velocity distributions and <span class="hlt">plasma</span> waves associated with the injection of an <span class="hlt">electron</span> beam into the ionosphere</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Frank, L. A.; Paterson, W. R.; Ashour-Abdalla, M.; Schriver, D.; Kurth, W. S.; Gurnett, D. A.</p> <p>1989-06-01</p> <p>An <span class="hlt">electron</span> beam was injected into Earth's ionosphere on August 1, 1985, the flight of the space shuttle /ital Challenger/ as part of the objectives of the Spacelab 2 mission. In the wake of the space shuttle a magnetically aligned <span class="hlt">sheet</span> of <span class="hlt">electrons</span> returning from the direction of propagation of the beam was detected with the free-flying <span class="hlt">plasma</span> Diagnostics Package. The thickness of this <span class="hlt">sheet</span> of returning <span class="hlt">electrons</span> was about 20 m. Large intensifications of broadband electrostatic noise were also observed within this <span class="hlt">sheet</span> of <span class="hlt">electrons</span>. A numerical simulation of the interaction of the <span class="hlt">electron</span> beam with the ambient ionospheric <span class="hlt">plasmas</span> is employed to show that the <span class="hlt">electron</span> beam excites <span class="hlt">electron</span> <span class="hlt">plasma</span> oscillations and that it is possible for the ion ascoustic instability to provide a returning flux of hot electorns by means of quasi-linear diffusion. /copyright/ American Geophysical Union 1989</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4459207','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4459207"><span id="translatedtitle">Increases in <span class="hlt">plasma</span> <span class="hlt">sheet</span> temperature with solar wind driving during substorm growth phases</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Forsyth, C; Watt, C E J; Rae, I J; Fazakerley, A N; Kalmoni, N M E; Freeman, M P; Boakes, P D; Nakamura, R; Dandouras, I; Kistler, L M; Jackman, C M; Coxon, J C; Carr, C M</p> <p>2014-01-01</p> <p>During substorm growth phases, magnetic reconnection at the magnetopause extracts ∼1015 J from the solar wind which is then stored in the magnetotail lobes. <span class="hlt">Plasma</span> <span class="hlt">sheet</span> pressure increases to balance magnetic flux density increases in the lobes. Here we examine <span class="hlt">plasma</span> <span class="hlt">sheet</span> pressure, density, and temperature during substorm growth phases using 9 years of Cluster data (>316,000 data points). We show that <span class="hlt">plasma</span> <span class="hlt">sheet</span> pressure and temperature are higher during growth phases with higher solar wind driving, whereas the density is approximately constant. We also show a weak correlation between <span class="hlt">plasma</span> <span class="hlt">sheet</span> temperature before onset and the minimum SuperMAG AL (SML) auroral index in the subsequent substorm. We discuss how energization of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> before onset may result from thermodynamically adiabatic processes; how hotter <span class="hlt">plasma</span> <span class="hlt">sheets</span> may result in magnetotail instabilities, and how this relates to the onset and size of the subsequent substorm expansion phase. PMID:26074645</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999JGR...10419993L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999JGR...10419993L"><span id="translatedtitle">Stability analysis of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> using Hall magnetohydrodynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, D.-Y.</p> <p>1999-09-01</p> <p>Linear stability analysis of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> configuration is performed using Hall magnetohydrodynamics, which is more appropriate than the strict ideal MHD for the stressed current <span class="hlt">sheet</span> during the substorm growth phase. By adding the Hall term in Ohm's law we study the impact of the error involved in assuming perfect conductivity on the stability. The ballooning-like mode with large perpendicular wavenumber is considered, and its basic eigenmode equations are derived. The ballooning instability is currently one of the strong candidates for causing the substorm onset. Numerical computations of the eigenmode equations are carried out for some model equilibria. It is found that the Hall-MHD effect is not so significant in determining the ballooning stability, as the result is not much different from that of ideal MHD: (1) The ballooning instability is rather easily triggered in the model where the field lines are not too much stretched but the <span class="hlt">plasma</span> beta still exceeds some critical value, which depends on the situation; (2) The ballooning mode, however, seems to be stabilized in the very stretched field models and is not destabilized by adding the Hall-MHD effect in such models. The result implies that the ballooning stability in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> seems to be much more dependent on equilibrium properties such as the field shape than on the physical formulation. It is further suggested that extensive field modeling and subsequent tests for the ballooning mode are a high priority in future in order to establish a firm connection between ballooning instability and the substorm onset.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_6 --> <div id="page_7" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="121"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMSM11D2326L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMSM11D2326L"><span id="translatedtitle">Variation of the <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> in the Near-Earth Magnetotail by the Impact of an Interplanetary Shock</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, E.; Parks, G. K.; Lin, N.; Kim, K.; Lee, D.; SEON, J.; Jin, H.</p> <p>2012-12-01</p> <p>It has been reported that Earth's magnetosphere is compressed by the impact of an interplanetary shock. ULF waves or pulses of electric fields are induced in the inner magnetosphere by the impact, which can energize radiation belt particles. In this study we report the observations of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> in the near-Earth magnetotail around ~-17 RE by the Cluster spacecraft when an interplanetary shock impacts Earth's magnetosphere. On 24 August 2005 an interplanetary shock impacted Earth's magnetosphere and induced a storm sudden commencement (SSC) and a magnetic storm. After the SSC both the density and temperature of <span class="hlt">plasmas</span> in the near-Earth magnetotail significantly increased. The current density in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> also increased, which implies that the <span class="hlt">plasma</span> <span class="hlt">sheet</span> was compressed. The increase of the particle fluxes of ions and <span class="hlt">electrons</span> was measured predominantly for E > ~30 keV up to ~100 keV, which is much lower than the energies of the particles observed in the radiation belt. The flux enhancement was more prominent for <span class="hlt">electrons</span> than ions, which suggests that the energization is more efficient for <span class="hlt">electrons</span> than ions. These observations show that the <span class="hlt">plasma</span> <span class="hlt">sheet</span> in the near-Earth magnetotail is affected by the impact of an interplanetary shock, but some aspects are different from those observed in the inner magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22299965','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22299965"><span id="translatedtitle">Three dimensional instabilities of an <span class="hlt">electron</span> scale current <span class="hlt">sheet</span> in collisionless magnetic reconnection</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jain, Neeraj; Bchner, Jrg</p> <p>2014-06-15</p> <p>In collisionless magnetic reconnection, <span class="hlt">electron</span> current <span class="hlt">sheets</span> (ECS) with thickness of the order of an <span class="hlt">electron</span> inertial length form embedded inside ion current <span class="hlt">sheets</span> with thickness of the order of an ion inertial length. These ECS's are susceptible to a variety of instabilities which have the potential to affect the reconnection rate and/or the structure of reconnection. We carry out a three dimensional linear eigen mode stability analysis of <span class="hlt">electron</span> shear flow driven instabilities of an <span class="hlt">electron</span> scale current <span class="hlt">sheet</span> using an <span class="hlt">electron</span>-magnetohydrodynamic <span class="hlt">plasma</span> model. The linear growth rate of the fastest unstable mode was found to drop with the thickness of the ECS. We show how the nature of the instability depends on the thickness of the ECS. As long as the half-thickness of the ECS is close to the <span class="hlt">electron</span> inertial length, the fastest instability is that of a translational symmetric two-dimensional (no variations along flow direction) tearing mode. For an ECS half thickness sufficiently larger or smaller than the <span class="hlt">electron</span> inertial length, the fastest mode is not a tearing mode any more and may have finite variations along the flow direction. Therefore, the generation of plasmoids in a nonlinear evolution of ECS is likely only when the half-thickness is close to an <span class="hlt">electron</span> inertial length.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6907757','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6907757"><span id="translatedtitle">Association of <span class="hlt">plasma</span> <span class="hlt">sheet</span> variations with auroral changes during substorms</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hones, E.W. Jr.; Craven, J.D.; Frank, L.A.; Parks, G.K.</p> <p>1988-01-01</p> <p>Images of the southern auroral oval taken by the University of Iowa auroral imaging instrumentation on the Dynamics Explorer 1 satellite during an isolated substorm are correlated with <span class="hlt">plasma</span> measurements made concurrently by the ISEE 1 satellite in the magnetotail. Qualitative magnetic field configuration changes necessary to relate the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary location to the latitude of the auroras are discussed. Evidence is presented that the longitudinal advances of the auroras after expansive phase onset are mappings of a neutral line lengthening across the near-tail. We observe a rapid poleward auroral surge, occurring about 1 hour after expansive phase onset, to coincide with the peak of the AL index and argue that the total set of observations at that time is consistent with the picture of a /open quotes/poleward leap/close quotes/ of the electrojet marking the beginning of the substorm's recovery. 9 refs. 3 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920045465&hterms=irm&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dirm','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920045465&hterms=irm&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dirm"><span id="translatedtitle">Pressure changes in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> during substorm injections</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kistler, L. M.; Moebius, E.; Baumjohann, W.; Paschmann, G.; Hamilton, D. C.</p> <p>1992-01-01</p> <p>Data from the CHEM instrument on AMPTE CCE, data from the 3D <span class="hlt">plasma</span> instrument and the SULEICA instrument on AMPTE IRM, and magnetometer data from both spacecraft are used to determine the particle pressure and total pressure as a function of radial distance in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> for periods before and after the onset of substorm-associated ion enhancements over the range 7-19 RE. Events were chosen that occurred during times of increasing magnetospheric activity, as determined by an increasing AE index, in which a sudden increase, or 'injection', of energetic particle flux is observed. It is shown that the simultaneous appearance of energetic particles and changes in the magnetic field results naturally from pressure balance and does not necessarily indicate that the local changing field is accelerating the particles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19990080077&hterms=McCarthy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DMcCarthy%252C%2BR','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19990080077&hterms=McCarthy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DMcCarthy%252C%2BR"><span id="translatedtitle">Understanding Substorms from the Auroral Ionosphere to the Distant <span class="hlt">Plasma</span> <span class="hlt">Sheet</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Parks, G. K.; Brittnacher, M.; Chen, L.; Chua, D.; Elsen, R.; Fillingim, M.; McCarthy, M.; Wilber, M.; Germany, G.; Spann, J.; Lin, R. P.</p> <p>1998-01-01</p> <p>The global polar UVI images have been correlated with observations from the ground, ionosphere, geomagnetic tail between 10-20 earth radii and the interplanetary space. One of the objectives of our study is to better understand the connection among many complex phenomena occurring close to Earth and those in the near--earth <span class="hlt">plasma</span> <span class="hlt">sheet</span>. We have examined the details of how the auroral and polar cap boundaries at different local times behave in relation to variations occurring in the solar wind, ionosphere and <span class="hlt">plasma</span> <span class="hlt">sheet</span> during substorms. We have also compared locations of boundaries deduced from images to <span class="hlt">electron</span> flux "boundaries" observed by polar orbiting spacecraft. Our results indicate that the ionospheric dynamics is important and polar cap and auroral oval boundaries expand and contract in a complicated but systematic way. These variations are correlated to solar wind parameters and growth and recovery phenomena in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. These results can be interpreted in terms of directly driven and/or unloading substorm processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25005914','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25005914"><span id="translatedtitle"><span class="hlt">Electronic</span> and optical properties of silicon based porous <span class="hlt">sheets</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Guo, Yaguang; Zhang, Shunhong; Wang, Qian</p> <p>2014-08-21</p> <p>Si based <span class="hlt">sheets</span> have attracted tremendous attention due to their compatibility with the well-developed Si-based semiconductor industry. On the basis of state-of-the-art theoretical calculations, we systematically study the stability, <span class="hlt">electronic</span> and optical properties of Si based porous <span class="hlt">sheets</span> including g-Si4N3, g-Si3N4, g-Si3N3 and g-Si3P3. We find that the g-Si3N3 and g-Si3P3 <span class="hlt">sheets</span> are thermally stable, while the g-Si4N3 and g-Si3N4 are unstable. Different from the silicene-like <span class="hlt">sheets</span> of SiN and Si3N which are nonplanar and metallic, both the porous g-Si3N3 and g-Si3P3 <span class="hlt">sheets</span> are planar and nonmetallic, and the former is an indirect band gap semiconductor with a band gap of 3.50 eV, while the latter is a direct band gap semiconductor with a gap of 1.93 eV. Analysis of the optical absorption spectrum reveals that the g-Si3P3 <span class="hlt">sheet</span> may have applications in solar absorbers owing to its narrow direct band gap and wide range optical absorption in the visible light spectrum. PMID:25005914</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRA..119.1827C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRA..119.1827C"><span id="translatedtitle">The quiet evening auroral arc and the structure of the growth phase near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Coroniti, F. V.; Pritchett, P. L.</p> <p>2014-03-01</p> <p>The <span class="hlt">plasma</span> pressure and current configuration of the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> that creates and sustains the quiet evening auroral arc during the growth phase of magnetospheric substorms is investigated. We propose that the quiet evening arc (QEA) connects to the thin near-Earth current <span class="hlt">sheet</span>, which forms during the development of the growth phase enhancement of convection. The current <span class="hlt">sheet</span>'s large polarization electric fields are shielded from the ionosphere by an Inverted-V parallel potential drop, thereby producing the <span class="hlt">electron</span> precipitation responsible for the arc's luminosity. The QEA is located in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> region of maximal radial pressure gradient and, in the east-west direction, follows the vanishing of the approximately dawn-dusk-directed gradient or fold in the <span class="hlt">plasma</span> pressure. In the evening sector, the boundary between the Region1 and Region 2 current systems occurs where the pressure maximizes (approximately radial gradient of the pressure vanishes) and where the approximately radial gradient of the magnetic flux tube volume also vanishes in an inflection region. The proposed intricate balance of <span class="hlt">plasma</span> <span class="hlt">sheet</span> pressure and currents may well be very sensitive to disruption by the arrival of equatorward traveling auroral streamers and their associated earthward traveling dipolarization fronts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/927792','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/927792"><span id="translatedtitle">A Gridded <span class="hlt">Electron</span> Gun for a <span class="hlt">Sheet</span> Beam Klystron</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Read, M.E.; Miram, G.; Ives, R.L.; Ivanov, V.; Krasnykh, A.; /SLAC</p> <p>2008-04-25</p> <p>This paper describes the development of an <span class="hlt">electron</span> gun for a <span class="hlt">sheet</span> beam klystron. Initially intended for accelerator applications, the gun can operate at a higher perveance than one with a cylindrically symmetric beam. Results of 2D and 3D simulations are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM11A2062F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM11A2062F"><span id="translatedtitle">Kinetic <span class="hlt">electron</span> bounce instability in a 2D current <span class="hlt">sheet</span> - Implication for substorm dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fruit, G.; Tur, A.; Louarn, P.</p> <p>2013-12-01</p> <p>In the general context of understanding the possible destabilization of the magnetotail before a substorm, we propose a kinetic model for electromagnetic ballooning-type instabilities in resonant interaction with trapped bouncing <span class="hlt">electrons</span> in a 2D current <span class="hlt">sheet</span>. Tur et al. 2010 and Fruit et al. 2013 already used this model to investigate the possibilities of electrostatic instabilities. Here, we generalize the model for full electromagnetic perturbations. Starting with a modified Harris <span class="hlt">sheet</span> as equilibrium state, the linearized gyrokinetic Vlasov equation is solved for electromagnetic fluctuations with period of the order of the <span class="hlt">electron</span> bounce period. The particle motion is restricted to its first Fourier component along the magnetic field and this allows the complete time integration of the non local perturbed distribution functions. The dispersion relation for electromagnetic modes is finally obtained through the quasineutrality condition and the Ampere's law for the current density. It is found that for mildly stretched current <span class="hlt">sheet</span> (Bz > 0.1 Blobes) undamped and stable modes oscillate at typical <span class="hlt">electron</span> bounce frequency with wavelength (in y) of the order of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> thickness. As the stretching of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> becomes more intense, the frequency of these normal modes decreases and beyond a certain threshold in epsilon=Bz/Blobes < 0.05 typically, the mode becomes explosive (pure imaginary frequency) with typical growing rate of a few tens of seconds. The free energy contained in the <span class="hlt">electron</span> bouncing motion could thus trigger and drive an electromagnetic instability able to disrupt the cross-tail current in a few seconds. The role of the temperature ratio Te/Ti is also evaluated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009A%26A...502..341W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009A%26A...502..341W"><span id="translatedtitle"><span class="hlt">Electron</span> acceleration in the turbulent reconnecting current <span class="hlt">sheets</span> in solar flares</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, G. P.; Huang, G. L.</p> <p>2009-07-01</p> <p>Context: We investigate the nonlinear evolution of the <span class="hlt">electron</span> distribution in the presence of the strong inductive electric field in the reconnecting current <span class="hlt">sheets</span> (RCS) of solar flares. Aims: We aim to study the characteristics of nonthermal <span class="hlt">electron</span>-beam <span class="hlt">plasma</span> instability and its influence on <span class="hlt">electron</span> acceleration in RCS. Methods: Including the external inductive field, the one-dimensional Vlasov simulation is performed with a realistic mass ratio for the first time. Results: Our principal findings are as follows: 1) the Buneman instability can be quickly excited on the timescale of 10-7 s for the typical parameters of solar flares. After saturation, the beam-<span class="hlt">plasma</span> instabilities are excited due to the non-Maxwellian <span class="hlt">electron</span> distribution; 2) the final velocity of the <span class="hlt">electrons</span> trapped by these waves is of the same order as the phase speed of the waves, while the untrapped <span class="hlt">electrons</span> continue to be accelerated; 3) the inferred anomalous resistance of the current <span class="hlt">sheet</span> and the energy conversion rate are basically of the same order as those previously estimated, e.g., the analysis of Martens. Conclusions: The Buneman instability is excited on the timescale of 10-7 s and the wave-particle resonant interaction limits the low-energy <span class="hlt">electrons</span> to be further accelerated in RCS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFMSM32A1138X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFMSM32A1138X"><span id="translatedtitle">Dynamics of the Firehose Instability in the Central <span class="hlt">Plasma</span> <span class="hlt">Sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, B.; Horton, W.; Wong, V.; van Dam, J.</p> <p>2003-12-01</p> <p>There is renewed interest in the nonlinear dynamics of the firehose instability in the high beta central <span class="hlt">plasma</span> <span class="hlt">sheet</span>. This strong instability produces order unity magnetic fluctuations that propagate up and down the magnetic field line as Alfvenic fluctuations. A new nonlinear model of this instability is presented where the anisotropy parameter A= ? 0(p_? -p_perpendicular to )/B2, the dispersion parameter of the ion gyradius over the thickness of the central <span class="hlt">plasma</span> <span class="hlt">sheet</span> and the sub-grid scale damping are the three key parameters. When the anisotropy parameter A is a few percent above the critical value of unity, the magnetic turbulence strongly increases. The E x B kinetic energy remains subdominant, so this process gives a direct conversion of <span class="hlt">plasma</span> energy to magnetic energy. We focus here on mapping out the state space for the different nonlinear states. Depending on the values of A, ? i/L_z and the sub-grid scale damping rates, we give examples of weak bursty soliton like states, weakly turbulent wave states, strong turbulence states, and nonsaturating secularly growing states The magnetic turbulence is a good candidate to explain the Pi-2 oscillations seen in association with bursty bulk flows and substorms (Sigsbee et al. 2002). A continual driving up of the parallel pressure anisotropy occurs through the inward convection of the flux tubes with their continuously shortening field line length or the discontinuous shortening with the onset of magnetic reconnection in the geotail. The Lagrangian codes of the Rice group show the firehose instability arising from the magnetic buoyancy effects which is used to explain the bursty bulk flows in Chen and Wolf (1999) and Ji and Wolf (2002). This work was supported by National Science Foundation Grant ATM-0229863. [1] Sigsbee et al., JGR, 2002. [2] Ji, S., and R. A. Wolf, JGR, 108(A5), 2003.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5523037','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5523037"><span id="translatedtitle"><span class="hlt">Electron</span> collision frequency in <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Boercker, D.B.; Rogers, F.J.; DeWitt, H.E.</p> <p>1982-03-01</p> <p>In strongly coupled, degenerate <span class="hlt">plasmas</span>, the <span class="hlt">electron</span> collision frequency has been described by the Ziman formula with the ion-ion correlations modeled by the classical one-component <span class="hlt">plasma</span> (OCP). However, this model fails to reproduce the correct quantum Lenard-Balescu result in the weak-coupling limit. It is demonstrated here that a recently obtained, correlation-function expression for the collision frequency reduces to the Ziman and Lenard-Balescu results in the appropriate limits. In addition, it is shown that an extension of the Lenard-Balescu result to include strong coupling can be interpreted as the Ziman collision frequency with the OCP structure factor replaced by the ion-ion structure factor for a two-component system. Numerical estimates of this structure factor are used to calculate the electrical conductivity in moderately coupled (GAMMA< or =2) hydrogen <span class="hlt">plasmas</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001APS..DPPGP1136S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001APS..DPPGP1136S"><span id="translatedtitle">Rf <span class="hlt">sheet-plasma</span> production using permanent magnets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sakawa, Youichi; Yano, Kentaro; Shoji, Tatsuo</p> <p>2001-10-01</p> <p>High-density <span class="hlt">sheet-plasmas</span> with a rectangular cross-section of 140 mm 20 mm are developed by inductive rf discharge using a rectangular discharge section and a pair of permanent magnets. The stainless-steel discharge section is 200 mm wide, 20 mm high, and 100 mm long. A pair of ferrite permanent magnets (length L_mag = 20 - 140 mm in S-N direction, width W_mag = 50 - 170 mm, and height = 24 mm) is placed on top and bottom of the discharge section and a static magnetic field of B0 ~= 600 - 800 G is generated under the center of the magnets. Rf current (frequency = 13.56 MHz and power P_rf <= 4.5 kW) is applied to an internal antenna covered with a quartz tube in the direction perpendicular to B_0. The antenna is located behind the magnets where B0 is nearly zero. <span class="hlt">Plasma</span> density np profile is controlled by varying W_mag and distance between the antenna and the magnets due to cusped magnetic field generated by magnets. 140 mm wide <span class="hlt">plasma</span> (np ~= 2.5 10^12 cm-3) of a uniformity variation within 90% is produced using 140 mm long antenna for L_mag = 20 mm, W_mag = 120 mm, Ar pressure = 20 mTorr, and P_rf = 3 kW.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvS..18h1304W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvS..18h1304W"><span id="translatedtitle">Optical <span class="hlt">plasma</span> torch <span class="hlt">electron</span> bunch generation in <span class="hlt">plasma</span> wakefield accelerators</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wittig, G.; Karger, O.; Knetsch, A.; Xi, Y.; Deng, A.; Rosenzweig, J. B.; Bruhwiler, D. L.; Smith, J.; Manahan, G. G.; Sheng, Z.-M.; Jaroszynski, D. A.; Hidding, B.</p> <p>2015-08-01</p> <p>A novel, flexible method of witness <span class="hlt">electron</span> bunch generation in <span class="hlt">plasma</span> wakefield accelerators is described. A quasistationary <span class="hlt">plasma</span> region is ignited by a focused laser pulse prior to the arrival of the <span class="hlt">plasma</span> wave. This localized, shapeable optical <span class="hlt">plasma</span> torch causes a strong distortion of the <span class="hlt">plasma</span> blowout during passage of the <span class="hlt">electron</span> driver bunch, leading to collective alteration of <span class="hlt">plasma</span> <span class="hlt">electron</span> trajectories and to controlled injection. This optically steered injection is more flexible and faster when compared to hydrodynamically controlled gas density transition injection methods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AdSpR..56.1194C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AdSpR..56.1194C"><span id="translatedtitle">Preliminary empirical model of inner boundary of ion <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cao, J. B.; Zhang, D.; Reme, H.; Dandouras, I.; Sauvaud, J. A.; Fu, H. S.; Wei, X. H.</p> <p>2015-09-01</p> <p>The penetration of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> into the inner magnetosphere is important to both ring current formation and spacecraft charging at geosynchronous orbit. This paper, using hot ion data recorded by HIA of TC-1/DSP, establishes an empirical model of the inner boundary of ion <span class="hlt">plasma</span> <span class="hlt">sheet</span> (IBIPS) on the near equatorial plane. All IBIPS are located inside geocentric radial distance of 9 RE. We divided local times (LT) into eight local time bins and found that during quiet times (Kp ⩽ 2-), the IBIPS is closest to the Earth on the pre-midnight side (LT = 1930-2130) and farthest on the dawn side (LT = 0430-0730), which differs from previous spiral models. The geocentric radius of IBIPS in each local time bin can be described by a linear fitting function: Rps = A + Bkp · Kp. The changing rate Bkp of the radius of IBIPS relative to Kp index on the midnight side (LT = 2230-0130) and post-night side (LT = 0130-0430) are the two largest (0.66 and 0.67), indicating that the IBIPS on the night side (LT = 2230-0430) moves fastest when Kp changes. Since the IBIPSs in different local times bins have different changing rates, both the size and shape of IBIPS change when Kp varies. The correlation coefficients between the radius of IBIPS and the instantaneous Kp increase with the increase of ΔT (the time difference between IBIPS crossing time and preceding Kp interval), which suggests that with the increase of ΔT, the radius of IBIPS is more and more controlled by instantaneous Kp, and the influence of preceding Kp becomes weaker. The response time of IBIPS to Kp is between 80 and 95 min. When ΔT > 95 min, the correlation coefficient basically keeps unchanged and only has a weak increase, suggesting that the IBIPS is mainly determined by the convection electric field represented by instantaneous Kp.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008NIMPB.266.2627N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008NIMPB.266.2627N"><span id="translatedtitle">Optimized H - extraction in an argon-magnesium seeded magnetized <span class="hlt">sheet</span> <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Noguera, Virginia R.; Blantocas, Gene Q.; Ramos, Henry J.</p> <p>2008-06-01</p> <p>The enhancement and optimization of H- extraction through argon and magnesium seeding of hydrogen discharges in a magnetized <span class="hlt">sheet</span> <span class="hlt">plasma</span> source are reported. The paper first presents the modification of the production chamber into a hexapole multicusp configuration resulting in decreased power requirements, improved <span class="hlt">plasma</span> confinement and longer filament lifetime. By this, a wider choice of discharge currents for sustained quiescent <span class="hlt">plasmas</span> is made possible. Second, the method of adding argon to the hydrogen <span class="hlt">plasma</span> similar to the scheme in Abate and Ramos [Y. Abate, H. Ramos, Rev. Sci. Instr. 71 (10) (2000) 3689] was performed to find the optimum conditions for H- formation and extraction. Using an E × B probe, H- yields were investigated at varied argon-hydrogen admixtures, different discharge currents and spatial points relative to the core <span class="hlt">plasma</span>. The optimum H- current density extracted at 3.0 cm from the <span class="hlt">plasma</span> core using 3.0 A <span class="hlt">plasma</span> current with 10% argon seeding increased by a factor of 2.42 (0.63 A/m2) compared to the measurement of Abate and Ramos [Y. Abate, H. Ramos, Rev. Sci. Instr. 71 (10) (2000) 3689]. Third, the argon-hydrogen <span class="hlt">plasma</span> at the extraction chamber is seeded with magnesium. Mg disk with an effective area of 22 cm2 is placed at the extraction region's anode biased 175 V with respect to the cathode. With Mg seeding, the optimum H- current density at the same site and discharge conditions increased by 4.9 times (3.09 A/m2). The enhancement effects were analyzed vis-à-vis information gathered from the usual Langmuir probe (<span class="hlt">electron</span> temperature and density), <span class="hlt">electron</span> energy distribution function (EEDF) and the ensuing dissociative attachment (DA) reaction rates at different spatial points for various <span class="hlt">plasma</span> discharges and gas ratios. Investigations on the changes in the effective <span class="hlt">electron</span> temperature and <span class="hlt">electron</span> density indicate that the enhancement is due to increased density of low-energy <span class="hlt">electrons</span> in the volume, conducive for DA reactions. With Mg, the density of <span class="hlt">electrons</span> with <span class="hlt">electron</span> temperature of about 3 eV increased 3 orders of magnitude from 2.76 × 1012 m-3 to 2.90 × 1015m-3.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApSS..357..771G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApSS..357..771G"><span id="translatedtitle">Restructured graphene <span class="hlt">sheets</span> embedded carbon film by oxygen <span class="hlt">plasma</span> etching and its tribological properties</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guo, Meiling; Diao, Dongfeng; Yang, Lei; Fan, Xue</p> <p>2015-12-01</p> <p>An oxygen <span class="hlt">plasma</span> etching technique was introduced for improving the tribological properties of the graphene <span class="hlt">sheets</span> embedded carbon (GSEC) film in <span class="hlt">electron</span> cyclotron resonance <span class="hlt">plasma</span> processing system. The nanostructural changing in the film caused by oxygen <span class="hlt">plasma</span> etching was examined by transmission <span class="hlt">electron</span> microscope, Raman spectroscopy and X-ray photoelectron spectroscopy, showing that the 3 nm thick top surface layer was restructured with smaller graphene nanocrystallite size as well as higher sp3 bond fraction. The surface roughness, mechanical behavior and tribological properties of the original GSEC and oxygen <span class="hlt">plasma</span> treated GSEC films were compared. The results indicated that after the oxygen <span class="hlt">plasma</span> treatment, the average roughness decreased from 20.8 1.1 nm to 1.9 0.1 nm, the hardness increased from 2.3 0.1 GPa to 2.9 0.1 GPa, the nanoscratch depth decreased from 64.5 5.4 nm to 9.9 0.9 nm, and the wear life increased from 930 390 cycles to more than 15,000 frictional cycles. The origin of the improved tribological behavior was ascribed to the 3 nm thick graphene nanocrystallite film. This finding can be expected for wide applications in nanoscale surface engineering.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSH43A4182K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSH43A4182K"><span id="translatedtitle">Magnetic reconnection at the solar wind current <span class="hlt">sheets</span> as a possible cause of strahl <span class="hlt">electrons</span> acceleration and SEP dropouts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Khabarova, O.; Zharkova, V. V.</p> <p>2014-12-01</p> <p>According to the shape of the <span class="hlt">electron</span> velocity distribution function, there are two populations of suprathermal <span class="hlt">electrons</span>: halo and strahls (beams). The halo <span class="hlt">electrons</span> are omni-directional, and strahls are magnetic field aligned beams of <span class="hlt">electrons</span> that predominantly move in the anti-sunward direction. Properties of strahls represent a great interest, because this population is most energetic, but its origination is still unclear. Usually, it is supposed that strahls is a focused part of halo <span class="hlt">electrons</span>, non-scattered during their propagation from the Sun. We demonstrate a possibility to better understand nature of strahls if to suggest their acceleration directly in the solar wind due to a magnetic reconnection, occurring at current <span class="hlt">sheets</span>. We use results of our PIC-simulation of particles behaviour at reconnecting current <span class="hlt">sheets</span> (Zharkova, Khabarova, ApJ, 2012) in order to explain such effects as:- mismatches between a position of suprathermal <span class="hlt">electrons</span> pitch-angle changes and real crossing of the heliospheric current <span class="hlt">sheet</span>,- correlation between heat flux/solar energetic particles dropouts and high <span class="hlt">plasma</span> beta,- occurrence of counterstreaming <span class="hlt">electrons</span> at the ICME front and at corotating shocks at r > 2 AU,- radial evolution of strahls/halo density.Multi-spacecraft observations (STEREO, ACE, Ulysses) of properties of suprathermal <span class="hlt">electrons</span> attributed to crossings of the heliospheric current <span class="hlt">sheet</span> as well as smaller-scale current <span class="hlt">sheets</span> during SEP events and CME-CIR interactions will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21274276','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21274276"><span id="translatedtitle">Validity of closed periodic magnetic focusing for <span class="hlt">sheet</span> <span class="hlt">electron</span> beams</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhao Ding</p> <p>2009-11-15</p> <p>Theoretical analyses and numerical calculations have demonstrated that a closed periodic cusped magnetic (PCM) field can effectively confine a <span class="hlt">sheet</span> <span class="hlt">electron</span> beam in two transverse directions (i.e., in the wide and narrow dimensions, simultaneously) for stable long distance transport in which the sizes of the beam cross section are set by referring to the present state of the art. Moreover, the method for matching the transverse magnetic focusing force and the inner space charge force in the wide dimension of the <span class="hlt">sheet</span> <span class="hlt">electron</span> beam is given, and the longitudinal periodic length and the cross sectional shape of the closed PCM focusing structure can be determined. Calculations also demonstrate that the optimum focusing state can be attained by adjusting the wide dimension on the transverse section of the closed PCM structure independently. The work presented in this paper indicates that the closed PCM structure is very promising for the confinement of the <span class="hlt">sheet</span> <span class="hlt">electron</span> beam, and it can be helpful for guiding practical engineering design.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920050936&hterms=irm&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dirm','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920050936&hterms=irm&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dirm"><span id="translatedtitle">Bursty bulk flows in the inner central <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Angelopoulos, V.; Baumjohann, W.; Kennel, C. F.; Coronti, F. V.; Kivelson, M. G.; Pellat, R.; Walker, R. J.; Luehr, H.; Paschmann, G.</p> <p>1992-01-01</p> <p>High-speed flows in the inner central <span class="hlt">plasma</span> <span class="hlt">sheet</span> (first reported by Baumjohann et al. (1990) are studied, together with the concurrent behavior of the <span class="hlt">plasma</span> and magnetic field, by using AMPTE/IRM data from about 9 to 19 R(E) in the earth magnetotail. The conclusions drawn from the detailed analysis of a representative event are reinforced by a superposed epoch analysis applied on two years of data. The high-speed flows organize themselves in 10-min time scale flow enhancements called here bursty-bulk flow (BBF) events. Both temporal and spatial effects are responsible for their bursty nature. The flow velocity exhibits peaks of very large amplitude with a characteristic time scale of the order of a minute, which are usually associated with magnetic field dipolarizations and ion temeperature increases. The BBFs represent intervals of enhanced earthward convection and energy transport per unit area in the y-z GSM direction of the order of 5 x 10 exp 19 ergs/R(E-squared).</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011APS..DPPCP9026S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011APS..DPPCP9026S"><span id="translatedtitle">Communication through a <span class="hlt">plasma</span> <span class="hlt">sheet</span> around a fast moving vehicle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sotnikov, V. I.; Mudaliar, S.; Genoni, T.; Rose, D.; Oliver, B. V.; Mehlhorn, T. A.</p> <p>2011-10-01</p> <p>Investigation of the complicated problem of scattering of electromagnetic waves on turbulent pulsations induced by a sheared flow inside a <span class="hlt">plasma</span> sheath is important for many applications including communication with hypersonic and re-entry vehicles. Theoretical and computational work aimed at improving the understanding of electromagnetic wave scattering processes in such turbulent <span class="hlt">plasmas</span> is presented. We analyze excitation of low frequency ion-acoustic type oscillations in a compressible <span class="hlt">plasma</span> flow with flow velocity shear and influence of such turbulent pulsations on scattering of high frequency electromagnetic waves used for communication purposes. We have appropriately included in our analysis the presence of <span class="hlt">electron</span> and ion collisions with neutrals as well as <span class="hlt">electron</span> - ion collisions. Results of numerical solutions for <span class="hlt">plasma</span> density and electric field perturbations for different velocity profiles have been used in the derived expressions for scattered wave energy and scattering cross section. Work supported by the Air Force Research Laboratory and Air Force Office Of Scientific Research Sandia is a multiprogram laboratory operated by Sandia Corporation, A Lockheed Martin Company, under contract DE-AC04-94AL85000.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940025621','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940025621"><span id="translatedtitle">A study of the formation and dynamics of the Earth's <span class="hlt">plasma</span> <span class="hlt">sheet</span> using ion composition data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lennartsson, O. W.</p> <p>1994-01-01</p> <p>Over two years of data from the Lockheed <span class="hlt">Plasma</span> Composition Experiment on the ISEE 1 spacecraft, covering ion energies between 100 eV/e and about 16 keV/e, have been analyzed in an attempt to extract new information about three geophysical issues: (1) solar wind penetration of the Earth's magnetic tail; (2) relationship between <span class="hlt">plasma</span> <span class="hlt">sheet</span> and tail lobe ion composition; and (3) possible effects of heavy terrestrial ions on <span class="hlt">plasma</span> <span class="hlt">sheet</span> stability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5370328','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5370328"><span id="translatedtitle">Poleward leaping auroras, the substorm expansive and recovery phases and the recovery of the <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hones, E.W.</p> <p>1992-01-01</p> <p>The auroral motions and geomagnetic changes the characterize the substorm's expansive phase, maximum epoch, and recovery phase are discussed in the context of their possible associations with the dropout and, especially, the recovery of the magnetotail <span class="hlt">plasma</span> <span class="hlt">sheet</span>. The evidence that there may be an inordinately sudden large poleward excursion or displacement (a poleward leap) of the electrojet and the auroras at the expansive phase-recovery phase transition is described. The close temporal association of these signatures with the recovery of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, observed on many occasions, suggests a causal relationship between substorm maximum epoch and recovery phase on the one hand and <span class="hlt">plasma</span> <span class="hlt">sheet</span> recovery on the other.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10146831','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10146831"><span id="translatedtitle">Poleward leaping auroras, the substorm expansive and recovery phases and the recovery of the <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hones, E.W.</p> <p>1992-05-01</p> <p>The auroral motions and geomagnetic changes the characterize the substorm`s expansive phase, maximum epoch, and recovery phase are discussed in the context of their possible associations with the dropout and, especially, the recovery of the magnetotail <span class="hlt">plasma</span> <span class="hlt">sheet</span>. The evidence that there may be an inordinately sudden large poleward excursion or displacement (a poleward leap) of the electrojet and the auroras at the expansive phase-recovery phase transition is described. The close temporal association of these signatures with the recovery of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, observed on many occasions, suggests a causal relationship between substorm maximum epoch and recovery phase on the one hand and <span class="hlt">plasma</span> <span class="hlt">sheet</span> recovery on the other.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21120312','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21120312"><span id="translatedtitle">Tearing instabilities driven by nonideal effects in the tail <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sundaram, A. K</p> <p>2008-05-15</p> <p>Using an extended magnetohydrodynamic description, the excitation of tearing modes is analytically investigated in the tail <span class="hlt">plasma</span> <span class="hlt">sheet</span> region that includes the magnetic field components B{sub 0x}(x,z) and B{sub 0z}(x,z). Taking <span class="hlt">electron</span> inertia and the Hall effect into account, a generalized technique is displayed for obtaining the tearing solutions near the singular layer, where the B{sub 0x}(x,z) field reverses sign at z=0. In two-dimensional tail geometry for scale lengths of order c/{omega}{sub pe}, it is shown that a localized tearing mode as well as a mode with broad spatial extent ({delta}{sup '}-driven mode) is excited near the field reversal region and these modes are mainly driven by <span class="hlt">electron</span> inertia. For appropriate current <span class="hlt">sheet</span> parameters, it is found that the localized mode becomes unstable in a couple of minutes while the mode with broad spatial width grows faster in 10 s. For three-dimensional perturbations wherein k{sub x},k{sub y}{ne}0, the combined effects of the Hall term and the <span class="hlt">electron</span> inertia are shown to excite new localized tearing modes with considerably enhanced growth rates ({gamma}>{omega}{sub ci})</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.7522B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.7522B"><span id="translatedtitle">Ion beams in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Birn, J.; Hesse, M.; Runov, A.; Zhou, X.-Z.</p> <p>2015-09-01</p> <p>We explore characteristics of energetic particles in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer associated with dipolarization events, based on simulations and observations. The simulations use the electromagnetic fields of an MHD simulation of magnetotail reconnection and flow bursts as basis for test particle tracing. They are complemented by self-consistent fully electrodynamic particle-in-cell (PIC) simulations. The test particle simulations confirm that crescent-shaped earthward flowing ion velocity distributions with strong perpendicular anisotropy can be generated as a consequence of near-tail reconnection, associated with earthward flows and propagating magnetic field dipolarization fronts. Both PIC and test particle simulations show that the ion distribution in the outflow region close to the reconnection site also consist of a beam superposed on an undisturbed population, which, however, does not show strong perpendicular anisotropy. This suggests that the crescent shape is created by quasi-adiabatic deformation from ion motion along the magnetic field toward higher field strength. The simulation results compare favorably with "Time History of Events and Macroscale Interactions during Substorms" observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20030062107','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20030062107"><span id="translatedtitle">Substorm Evolution in the Near-Earth <span class="hlt">Plasma</span> <span class="hlt">Sheet</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Erickson, Gary M.</p> <p>2003-01-01</p> <p>The goal of this project is to determine precursors and signatures of local substorm onset and how they evolve in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> using the Geotail near-Earth database. This project is part of an ongoing investigation involving this PI, Nelson Maynard (Mission Research Corporation), and William Burke (AFRL) toward an empirical understanding of the onset and evolution of substorms. The first year began with dissemination of our CRRES findings, which included an invited presentation and major publication. The Geotail investigation began with a partial survey of onset signature types at distances X less than 15 R(sub E) for the first five months (March-July 1995) of the Geotail near-Earth mission. During the second year, Geotail data from March 1995 to present were plotted. Various signatures at local onset were catalogued for the period through 1997. During this past year we performed a survey of current-disruption-like (CD-like) signatures at distances X less than or equal to 14 R(sub E) for the three years 1995-1997.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23003270','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23003270"><span id="translatedtitle">Plasmoid ejection and secondary current <span class="hlt">sheet</span> generation from magnetic reconnection in laser-<span class="hlt">plasma</span> interaction.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dong, Quan-Li; Wang, Shou-Jun; Lu, Quan-Ming; Huang, Can; Yuan, Da-Wei; Liu, Xun; Lin, Xiao-Xuan; Li, Yu-Tong; Wei, Hui-Gang; Zhong, Jia-Yong; Shi, Jian-Rong; Jiang, Shao-En; Ding, Yong-Kun; Jiang, Bo-Bin; Du, Kai; He, Xian-Tu; Yu, M Y; Liu, C S; Wang, Shui; Tang, Yong-Jian; Zhu, Jian-Qiang; Zhao, Gang; Sheng, Zheng-Ming; Zhang, Jie</p> <p>2012-05-25</p> <p>Reconnection of the self-generated magnetic fields in laser-<span class="hlt">plasma</span> interaction was first investigated experimentally by Nilson et al. [Phys. Rev. Lett. 97, 255001 (2006)] by shining two laser pulses a distance apart on a solid target layer. An elongated current <span class="hlt">sheet</span> (CS) was observed in the <span class="hlt">plasma</span> between the two laser spots. In order to more closely model magnetotail reconnection, here two side-by-side thin target layers, instead of a single one, are used. It is found that at one end of the elongated CS a fanlike <span class="hlt">electron</span> outflow region including three well-collimated <span class="hlt">electron</span> jets appears. The (>1 MeV) tail of the jet energy distribution exhibits a power-law scaling. The enhanced <span class="hlt">electron</span> acceleration is attributed to the intense inductive electric field in the narrow <span class="hlt">electron</span> dominated reconnection region, as well as additional acceleration as they are trapped inside the rapidly moving plasmoid formed in and ejected from the CS. The ejection also induces a secondary CS. PMID:23003270</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870041537&hterms=bochum&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dbochum','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870041537&hterms=bochum&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dbochum"><span id="translatedtitle">On the generation of field-aligned <span class="hlt">plasma</span> flow at the boundary of the <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schindler, K.; Birn, J.</p> <p>1987-01-01</p> <p>A possible cause of the large <span class="hlt">plasma</span> flow velocities parallel to the magnetic field (which were observed in spacecraft experiments) near the boundary of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> in the earth's magnetotail is considered in the framework of a magnetohydrodynamic model. It is shown for steady-state configurations that high parallel flow velocities can be expected to exist on field lines connecting to a region of weak magnetic field. The physical mechanism causing large values of the parallel velocity component can be visualized as a strong imbalance of perpendicular mass flux into and out of magnetic flux tubes passing through regions where the magnetic field is weak and inhomogeneous. The value of the parallel velocity component is evaluated, and it is found that it can substantially exceed the perpendicular velocity (by as much as a factor of 40). The results are applied to the earth's magnetotail; it is found that this mechanism is able to explain the parallel flow velocities near the boundary of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> in the range of several hundreds of km/s.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19860049558&hterms=earths+layers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dearths%2Blayers','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19860049558&hterms=earths+layers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dearths%2Blayers"><span id="translatedtitle">Energetic particle beams in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer following substorm expansion - Simultaneous near-earth and distant tail observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Scholer, M.; Baker, D. N.; Gloeckler, G.; Ipavich, F. M.; Galvin, A. B.; Klecker, B.; Terasawa, T.; Tsurutani, B. T.</p> <p>1986-01-01</p> <p>Simultaneous observations of ions and <span class="hlt">electron</span> beams in the near-earth and deep magnetotail following the onset of substorm are analyzed in terms of the substorm neutral line model. The observations were collected on March 20, 1983 with ISSE 1 and 3. Energy fluxes and intensity-time profiles of protons and <span class="hlt">electrons</span> are studied. The data reveal that the reconnection at the near-earth neutral line produces ions and <span class="hlt">electrons</span> for the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer. The maximum electric potential along the neutral line is evaluated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EPJAP..6030401O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EPJAP..6030401O"><span id="translatedtitle">Controllable formation of graphene and graphene oxide <span class="hlt">sheets</span> using photo-catalytic reduction and oxygen <span class="hlt">plasma</span> treatment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ostovari, Fatemeh; Abdi, Yaser; Ghasemi, Foad</p> <p>2012-12-01</p> <p>Au/SiO2/Si interdigital electrodes with thickness of 1 ?m were created on silicon substrate. Graphene oxide (GO) <span class="hlt">sheets</span> hanging from these electrodes were obtained by spin coating of chemically synthesized GO dispersed in water. We used UV-light-induced photo-catalytic activity of titanium oxide nanoparticles to reduce the GO layer. Effects of the photo-induced chemical reduction on the conductivity of the GO were investigated. Also, low power DC <span class="hlt">plasma</span> was used for oxidation of the <span class="hlt">sheets</span>. Oxygen bombardment leads to <span class="hlt">sheets</span> with low electrical conductivity. Measurements show that graphene and GO <span class="hlt">sheets</span> with the controlled electrical conductivity were obtained by these processes. Scanning <span class="hlt">electron</span> and atomic force microscopy were used to study the morphology of the TiO2/GO and graphene structures. X-ray diffraction and Raman scattering analysis were used to verify the structural characteristics of the prepared <span class="hlt">sheets</span>. Analysis showed a gradual increase in the number of C-O bonds on the surface of the graphene layer as a result of increasing the time of <span class="hlt">plasma</span> bombardment. Based on the Raman spectroscopy, the photo-catalytic activity of TiO2 nanoparticles resulted in a decrease in the number of C-O bonds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.6420P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.6420P"><span id="translatedtitle">THEMIS observation of Kinetic Ballooning/Interchange Waves in the High Bz <span class="hlt">Plasma</span> <span class="hlt">Sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Panov, Evgeny V.; Nakamura, Rumi; Kubyshkina, Marina V.; Baumjohann, Wolfgang; A, Sergeev, Victor</p> <p>2015-04-01</p> <p>Using THEMIS observations of <span class="hlt">plasma</span> <span class="hlt">sheet</span> oscillations with kinetic ballooning/interchange instability (BICI) signatures, we investigate the properties of the waves when a high background <span class="hlt">plasma</span> <span class="hlt">sheet</span> Bz is seen. We find that such waves are in a better agreement with the existing kinetic simulations. Using adapted Tsyganenko models, we also show conjugate all-sky camera observations in the course of the development of the waves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950045562&hterms=yamamoto&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dyamamoto','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950045562&hterms=yamamoto&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dyamamoto"><span id="translatedtitle">Geotail observations of spiky electric fields and low-frequency waves in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cattell, C.; Mozer, F.; Tsuruda, K.; Hayakawa, H.; Nakamura, M.; Okada, T.; Kokubun, S.; Yamamoto, T.</p> <p>1994-01-01</p> <p>Electric field data from the Geotail spacecraft provide an opportunity to extend the observations of spiky fields made by International Sun Earth Explorer-1 (ISEE-1) to a region of the magnetosphere where quasistatic electric field measurements have not previously been msde, to examine their possible importance in the dynamics of the middle and distant tail, and to test some hypotheses about their formation. In this paper, examples of large fields in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and its boundary at radial distances up to approximately 90 R(sub E) are presented. It is shown that three different types of large electric fields can occur: (1) spiky fields; (2) 'DC' fields; and (3) waves at frequencies comparable to the lower hybrid frequency. There is usually a gradation between (1) and (3), and often large electric field spikes are embedded in regions of lower amplitude waves. The waves tend to occur in short (few to 10's of seconds) packets whose start and stop times are not always correlated with changes in the magnetic field and/or density (as indicated by the spacecraft potential). The peak frequency is often less than but comparable to the lower hybrid frequency in agreement with theories of lower hybrid drift waves in the magnetotail. The largest spikes are not always associated with the largest changes in the spacecraft potential and/or magnetic field. It is suggested that the spiky fields may represent the nonlinear development of the waves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013aero.confE.127H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013aero.confE.127H"><span id="translatedtitle">Creating standardized <span class="hlt">electronic</span> data <span class="hlt">sheets</span> for applications and devices</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hansen, L. J.; Lanza, D.</p> <p></p> <p>The Air Force Research Laboratory (AFRL) continues to develop infrastructure to enable the modular construction of satellites using an open network architecture and off-the-shelf avionics for space systems. Recent efforts have included the refinement of an ontology to formalize a standard language for the exchange of data and commands between components, including hardware and software, which is still evolving. AFRL is also focusing effort on creating standard interfaces using <span class="hlt">electronic</span> data <span class="hlt">sheets</span> based on this recently defined ontology. This paper will describe the development of standard interfaces that are documented in terms of an <span class="hlt">electronic</span> datasheet for a specific application. The datasheet will identify the standard interfaces between hardware devices and software applications that are needed for a specific satellite function, in this case, a spacecraft guidance, navigation, and control (GN& C) application for Sun pointing. Finally, the benefits of using standardized interfaces will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22402426','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22402426"><span id="translatedtitle"><span class="hlt">Electronic</span>, phononic, and thermoelectric properties of graphyne <span class="hlt">sheets</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sevinli, Hldun; Sevik, Cem</p> <p>2014-12-01</p> <p><span class="hlt">Electron</span>, phonon, and thermoelectric transport properties of ?-, ?-, ?-, and 6,6,12-graphyne <span class="hlt">sheets</span> are compared and contrasted with those of graphene. ?-, ?-, and 6,6,12-graphynes, with direction dependent Dirac dispersions, have higher <span class="hlt">electronic</span> transmittance than graphene. ?-graphyne also attains better electrical conduction than graphene except at its band gap. Vibrationally, graphene conducts heat much more efficiently than graphynes, a behavior beyond an atomic density differences explanation. Seebeck coefficients of the considered Dirac materials are similar but thermoelectric power factors decrease with increasing effective speeds of light. ?-graphyne yields the highest thermoelectric efficiency with a thermoelectric figure of merit as high as ZT?=?0.45, almost an order of magnitude higher than that of graphene.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21357551','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21357551"><span id="translatedtitle">Short pulse, high power microwave radiation source with a laser-induced <span class="hlt">sheet</span> <span class="hlt">plasma</span> mirror</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Higashiguchi, Takeshi; Yugami, Noboru</p> <p>2009-05-01</p> <p>We have demonstrated the short pulse, high power microwave radiation source using an ultraviolet laser-induced <span class="hlt">sheet</span> <span class="hlt">plasma</span> mirror in a gas-filled x-band rectangular waveguide from the conventional microwave sources and components. A laser-induced <span class="hlt">sheet</span> <span class="hlt">plasma</span> with an overdense <span class="hlt">plasma</span> acts as a <span class="hlt">plasma</span> mirror. The long pulse propagating in the gas-filled waveguide was sliced by the <span class="hlt">sheet</span> <span class="hlt">plasma</span> mirror at two different points along the waveguide. We observed about twice the power of the pulse by adding the two sliced microwave pulses produced by this scheme. A maximum peak power of 200 kW with a pulse duration of 10 ns (full width at half maximum) from the long microwave pulse source with a pulse duration of 0.8 mus was observed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22218331','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22218331"><span id="translatedtitle">Nonlinear <span class="hlt">electron</span> oscillations in a warm <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sarkar, Anwesa; Maity, Chandan; Chakrabarti, Nikhil</p> <p>2013-12-15</p> <p>A class of nonstationary solutions for the nonlinear <span class="hlt">electron</span> oscillations of a warm <span class="hlt">plasma</span> are presented using a Lagrangian fluid description. The solution illustrates the nonlinear steepening of an initial Gaussian <span class="hlt">electron</span> density disturbance and also shows collapse behavior in time. The obtained solution may indicate a class of nonlinear transient structures in an unmagnetized warm <span class="hlt">plasma</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19810050965&hterms=Planck+Max&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2528Planck%2BMax%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19810050965&hterms=Planck+Max&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2528Planck%2BMax%2529"><span id="translatedtitle">Substorm-related <span class="hlt">plasma</span> <span class="hlt">sheet</span> motions as determined from differential timing of <span class="hlt">plasma</span> changes at the ISEE satellites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Forbes, T. G.; Hones, E. W., Jr.; Bame, S. J.; Asbridge, J. R.; Paschmann, G.; Sckopke, N.; Russell, C. T.</p> <p>1981-01-01</p> <p>From an ISEE survey of substorm dropouts and recoveries during the period February 5 to May 25, 1978, 66 timing events observed by the Los Alamos Scientific Laboratory/Max-Planck-Institut Fast <span class="hlt">Plasma</span> Experiments were studied in detail. Near substorm onset, both the average timing velocity and the bulk flow velocity at the edge of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> are inward, toward the center. Measured normal to the surface of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, the timing velocity is 23 + or - 18 km/s and the proton flow velocity is 20 + or - 8 km/s. During substorm recovery, the <span class="hlt">plasma</span> <span class="hlt">sheet</span> reappears moving outward with an average timing velocity of 133 + or - 31 km/s; however, the corresponding proton flow velocity is only 3 + or - 7 km/s in the same direction. It is suggested that the difference between the average timing velocity for the expansion of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and the <span class="hlt">plasma</span> bulk flow perpendicular to the surface of the <span class="hlt">sheet</span> during substorm recovery is most likely the result of surface waves moving past the position of the satellites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhPl...22a2309H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhPl...22a2309H"><span id="translatedtitle"><span class="hlt">Electron</span> vortex magnetic holes: A nonlinear coherent <span class="hlt">plasma</span> structure</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Haynes, Christopher T.; Burgess, David; Camporeale, Enrico; Sundberg, Torbjorn</p> <p>2015-01-01</p> <p>We report the properties of a novel type of sub-proton scale magnetic hole found in two dimensional particle-in-cell simulations of decaying turbulence with a guide field. The simulations were performed with a realistic value for ion to <span class="hlt">electron</span> mass ratio. These structures, <span class="hlt">electron</span> vortex magnetic holes (EVMHs), have circular cross-section. The magnetic field depression is associated with a diamagnetic azimuthal current provided by a population of trapped <span class="hlt">electrons</span> in petal-like orbits. The trapped <span class="hlt">electron</span> population provides a mean azimuthal velocity and since trapping preferentially selects high pitch angles, a perpendicular temperature anisotropy. The structures arise out of initial perturbations in the course of the turbulent evolution of the <span class="hlt">plasma</span>, and are stable over at least 100 <span class="hlt">electron</span> gyroperiods. We have verified the model for the EVMH by carrying out test particle and PIC simulations of isolated structures in a uniform <span class="hlt">plasma</span>. It is found that (quasi-)stable structures can be formed provided that there is some initial perpendicular temperature anisotropy at the structure location. The properties of these structures (scale size, trapped population, etc.) are able to explain the observed properties of magnetic holes in the terrestrial <span class="hlt">plasma</span> <span class="hlt">sheet</span>. EVMHs may also contribute to turbulence properties, such as intermittency, at short scale lengths in other astrophysical <span class="hlt">plasmas</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22407995','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22407995"><span id="translatedtitle"><span class="hlt">Electron</span> vortex magnetic holes: A nonlinear coherent <span class="hlt">plasma</span> structure</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Haynes, Christopher T. Burgess, David; Sundberg, Torbjorn; Camporeale, Enrico</p> <p>2015-01-15</p> <p>We report the properties of a novel type of sub-proton scale magnetic hole found in two dimensional particle-in-cell simulations of decaying turbulence with a guide field. The simulations were performed with a realistic value for ion to <span class="hlt">electron</span> mass ratio. These structures, <span class="hlt">electron</span> vortex magnetic holes (EVMHs), have circular cross-section. The magnetic field depression is associated with a diamagnetic azimuthal current provided by a population of trapped <span class="hlt">electrons</span> in petal-like orbits. The trapped <span class="hlt">electron</span> population provides a mean azimuthal velocity and since trapping preferentially selects high pitch angles, a perpendicular temperature anisotropy. The structures arise out of initial perturbations in the course of the turbulent evolution of the <span class="hlt">plasma</span>, and are stable over at least 100 <span class="hlt">electron</span> gyroperiods. We have verified the model for the EVMH by carrying out test particle and PIC simulations of isolated structures in a uniform <span class="hlt">plasma</span>. It is found that (quasi-)stable structures can be formed provided that there is some initial perpendicular temperature anisotropy at the structure location. The properties of these structures (scale size, trapped population, etc.) are able to explain the observed properties of magnetic holes in the terrestrial <span class="hlt">plasma</span> <span class="hlt">sheet</span>. EVMHs may also contribute to turbulence properties, such as intermittency, at short scale lengths in other astrophysical <span class="hlt">plasmas</span>.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007JGRE..112.2003N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007JGRE..112.2003N"><span id="translatedtitle">Vertical <span class="hlt">sheets</span> of dense <span class="hlt">plasma</span> in the topside Martian ionosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nielsen, E.; Wang, X.-D.; Gurnett, D. A.; Kirchner, D. L.; Huff, R.; Orosei, R.; Safaeinili, A.; Plaut, J. J.; Picardi, G.</p> <p>2007-02-01</p> <p>The low-frequency radar, Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS), on board the Mars Express spacecraft is used to sound <span class="hlt">electron</span> densities in the topside Martian ionosphere. The radar records the delay times to echoes of reflected radio waves as a function of frequency, yielding spectrograms with traces of radar echoes. At times, two traces are present in spectrograms of the Martian ionosphere. One of these traces corresponds to reflections from the direction to nadir. The other trace originates in a localized reflector in the ionosphere. The local reflectors can be associated with the cusplike regions of near-vertical crustal magnetic fields. The apparent nadir angle of reflection can occasionally increase to 90. This suggests that steep gradients of the altitude of the <span class="hlt">electron</span> isodensity exist in the Martian ionosphere and indicates rapid horizontal spatial variations of vertical diffusion of Martian <span class="hlt">plasma</span>. Such gradients may arise owing to preferential access of solar wind to the cusplike regions or to precipitation of energetic <span class="hlt">electrons</span> from acceleration regions located on cusp magnetic field lines high above the ionosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6399137','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6399137"><span id="translatedtitle">Associations of geomagnetic activity with <span class="hlt">plasma</span> <span class="hlt">sheet</span> thinning and expansion: A statistical study</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hones,Jr., E.W.; Pytte, T.; West,Jr., H.I.</p> <p>1984-07-01</p> <p>Associations of geomagnetic activity in the auroral zone with thinnings and expansions of the magnetotail <span class="hlt">plasma</span> <span class="hlt">sheet</span> are examined statistically in this paper. We first identified many <span class="hlt">plasma</span> <span class="hlt">sheet</span> thinnings and expansions in <span class="hlt">plasma</span> and particle data from VELA satellites and from OGO 5 without reference to the ground magnetic data. These events were grouped according to the location of the detecting satellite in the magnetotail. For each such group the times of thinning or expansion were then used as fiducial times in a superposed-epoch analysis of the geomagnetic AL index values that were recorded in 8-hour intervals centered on the event times. The results show that many <span class="hlt">plasma</span> <span class="hlt">sheet</span> thinnings and expansions are related to discrete negative bay structures that are the classical signature of substorms. Furthermore, they support earlier findings that <span class="hlt">plasma</span> <span class="hlt">sheet</span> thinning and expansion at the VELA orbit (rroughly-equal18 R/sub E/) tend to be associated with the onset of the auroral zone negative bay and the beginning of its subsidence, respectively. Earthward of rroughly-equal13-15 R/sub E/, <span class="hlt">plasma</span> <span class="hlt">sheet</span> expansion occurs near the time of the onset of the negative bay, again in agreement with earlier findings. A large fraction of <span class="hlt">plasma</span> <span class="hlt">sheet</span> expansions to half thicknesses of > or approx. =6 R/sub E/ at the VELA orbit are associated not with a baylike geomagnetic disturbance but with subsidence of a prolonged interval of disturbance. The study also shows that many <span class="hlt">plasma</span> <span class="hlt">sheet</span> expansions are related simply to generally enhanced geomagnetic activity showing no baylike or other distinctive features.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19780062870&hterms=buried+layer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dburied%2Blayer','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19780062870&hterms=buried+layer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dburied%2Blayer"><span id="translatedtitle">The effect of local magnetic fields on the lunar photoelectron layer while the moon is in the <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Burke, W. J.; Reiff, P. H.; Reasoner, D. L.</p> <p>1975-01-01</p> <p>Data from the Charged Particle Lunar Environment Experiment (CPLEE), at the Apollo 14 site, are used to investigate the interactive properties of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and the lunar photoelectron layer. It is shown that the predictions of the Guernsey-Fu model are compatible with SIDE but not CPLEE observations. The apparent contradiction is resolved by fitting the remanent magnetic field to that of a dipole buried about 1.1 km beneath the surface. In this case a charge separation layer must form above the instrument due to the different rigidities of <span class="hlt">plasma</span> <span class="hlt">sheet</span> <span class="hlt">electrons</span> and protons. The qualitative properties of the charge separation layer needed to reconcile CPLEE and SIDE observations are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPlPh..81f9006J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPlPh..81f9006J"><span id="translatedtitle">Effect of guide field on three-dimensional <span class="hlt">electron</span> shear flow instabilities in <span class="hlt">electron</span> current <span class="hlt">sheets</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jain, Neeraj; Bchner, Jrg</p> <p>2015-12-01</p> <p>> is the equilibrium magnetic field) can be recovered from the general resonance conditions in the limit of weak dissipation. The conditions (relating current <span class="hlt">sheet</span> thickness, strength of the guide field and wavenumbers) for the non-existence of tearing mode are obtained from the general mode resonance conditions. We discuss the role of <span class="hlt">electron</span> shear flow instabilities in magnetic reconnection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19750048351&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dlazarus','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19750048351&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dlazarus"><span id="translatedtitle">Preliminary interpretation of <span class="hlt">plasma</span> <span class="hlt">electron</span> observations at the third encounter of Mariner 10 with Mercury</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hartle, R. E.; Ogilvie, K. W.; Scudder, J. D.; Bridge, H. S.; Siscoe, G. L.; Lazarus, A. J.; Vasyliunas, V. M.; Yeates, C. M.</p> <p>1975-01-01</p> <p><span class="hlt">Plasma</span> <span class="hlt">electron</span> count observations made during the first and third encounters of Mariner 10 with Mercury (i.e., during Mercury I and III) are reported. They provide detailed information on the magnetosphere of Mercury, especially those from Mercury III. A low-flux region was observed about closest approach (CA) of Mercury III, whereas no such region was detected by the lower-latitude Mercury I; a hot <span class="hlt">plasma</span> <span class="hlt">sheet</span> was measured on the outgoing (and near-equator) trajectory of Mercury I, while only cool <span class="hlt">plasma</span> <span class="hlt">sheets</span> were observed in the magnetosphere by Mercury III. Findings are similar, on a reduced scale, to models of the earth's magnetosphere and magnetosheath.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6904217','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6904217"><span id="translatedtitle">Experiments on a reflex-type <span class="hlt">sheet</span> <span class="hlt">plasma</span> negative-ion source</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ando, A.; Kuroda, T.; Oka, Y.; Kaneko, O.; Karita, A.; Kawamoto, T. )</p> <p>1990-01-01</p> <p>Negative hydrogen ions are extracted from a reflex-type <span class="hlt">sheet</span> <span class="hlt">plasma</span>. <span class="hlt">Electron</span> density and temperature profiles are measured with changing the filling gas pressure, and they are optimized to the H{sup {minus}} production at the optimum gas pressure. The optimum gas pressure is 5 mTorr for the discharge current {ital I}{sub {ital d}} =2 A. As the discharge current {ital I}{sub {ital d}} increases, H{sup {minus}} current increases linearly corresponding to the density increase in the center region, but saturates above {ital I}{sub {ital d}} =40 A. The maximum extracted H{sup {minus}} current density of 4 mA/cm{sup 2} is obtained at {ital I}{sub {ital d}}=100 A.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.3702S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.3702S"><span id="translatedtitle">Role of turbulent transport in the evolution of the ? distribution functions in the <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stepanova, Marina; Antonova, Elizaveta E.</p> <p>2015-05-01</p> <p>We studied the evolution of ion and <span class="hlt">electron</span> distribution functions, approximated by ? distributions, in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> with the distance from the Earth using the data of the Time History of Events and Macroscale Interactions during Substorms spacecraft mission. Five events were used to calculate the main parameters of the ? distribution. For these events at least four spacecraft were aligned along the tail between approximately 7 and 30 RE. It was found that for the majority of events the values of ? increase tailward. The observed radial profiles could be related to the inner magnetosphere sources of particle acceleration and to the net tailward transport of particles. This net transport is the result of a balance between the average regular bulk transport toward the Earth and the turbulent transport by eddies in the tailward direction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21399937','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21399937"><span id="translatedtitle">Spectroscopic measurements of the <span class="hlt">electron</span> and ion temperatures and effective ion charge in current <span class="hlt">sheets</span> formed in two- and three-dimensional magnetic configurations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Voronov, G. S.; Kyrie, N. P.; Markov, V. S.; Ostrovskaya, G. V.; Frank, A. G.</p> <p>2008-12-15</p> <p>The spatial distributions of the <span class="hlt">electron</span> temperature and density, the effective and average ion charges, and the thermal and directed ion velocities in current <span class="hlt">sheets</span> formed in two-dimensional magnetic fields and three-dimensional magnetic configurations with an X line were studied using spectroscopic and interference holographic methods. The main attention was paid to studying the time evolution of the intensities of spectral lines of the working-gas (argon) and impurity ions under different conditions. Using these data, the <span class="hlt">electron</span> temperature was calculated with the help of an original mathematical code based on a collisional-radiative <span class="hlt">plasma</span> model incorporating the processes of ionization and excitation, as well as MHD <span class="hlt">plasma</span> flows generated in the stage of the current-<span class="hlt">sheet</span> formation. It is shown that the <span class="hlt">electron</span> temperature depends on the longitudinal magnetic field, whereas the ion temperature is independent of it. The effective ion charge of the current-<span class="hlt">sheet</span> <span class="hlt">plasma</span> was determined for the first time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19760008620&hterms=Auroras&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DAuroras','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19760008620&hterms=Auroras&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DAuroras"><span id="translatedtitle">ATS-5 observations of <span class="hlt">plasma</span> <span class="hlt">sheet</span> particles before the expansion-phase onset, appendix C.. [<span class="hlt">plasma</span>-particle interactions, magnetic storms and auroras</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fujii, K.; Nishida, A.; Sharp, R. D.; Shelley, E. G.</p> <p>1975-01-01</p> <p>Behavior of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> around its earthward edge during substorms was studied by using high resolution (every 2.6 sec) measurements of proton and <span class="hlt">electron</span> fluxes by ATS-5. In the injection region near midnight the flux increase at the expansion-phase onset is shown to lag behind the onset of the low-latitude positive bay by several minutes. Depending upon the case, before the above increase (1) the flux stays at a constant level, (2) it gradually increases for some tens of minutes, or (3) it briefly drops to a low level. Difference in the position of the satellite relative to the earthward edge and to the high-latitude boundary of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> is suggested as a cause of the above difference in flux variations during the growth phase of substorms. Magnetograms and tables (data) are shown.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22258614','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22258614"><span id="translatedtitle">Low <span class="hlt">sheet</span> resistance titanium nitride films by low-temperature <span class="hlt">plasma</span>-enhanced atomic layer deposition using design of experiments methodology</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Burke, Micheal Blake, Alan; Povey, Ian M.; Schmidt, Michael; Petkov, Nikolay; Carolan, Patrick; Quinn, Aidan J.</p> <p>2014-05-15</p> <p>A design of experiments methodology was used to optimize the <span class="hlt">sheet</span> resistance of titanium nitride (TiN) films produced by <span class="hlt">plasma</span>-enhanced atomic layer deposition (PE-ALD) using a tetrakis(dimethylamino)titanium precursor in a N{sub 2}/H{sub 2} <span class="hlt">plasma</span> at low temperature (250 °C). At fixed chamber pressure (300 mTorr) and <span class="hlt">plasma</span> power (300 W), the <span class="hlt">plasma</span> duration and N{sub 2} flow rate were the most significant factors. The lowest <span class="hlt">sheet</span> resistance values (163 Ω/sq. for a 20 nm TiN film) were obtained using <span class="hlt">plasma</span> durations ∼40 s, N{sub 2} flow rates >60 standard cubic centimeters per minute, and purge times ∼60 s. Time of flight secondary ion mass spectroscopy data revealed reduced levels of carbon contaminants in the TiN films with lowest <span class="hlt">sheet</span> resistance (163 Ω/sq.), compared to films with higher <span class="hlt">sheet</span> resistance (400–600 Ω/sq.) while transmission <span class="hlt">electron</span> microscopy data showed a higher density of nanocrystallites in the low-resistance films. Further significant reductions in <span class="hlt">sheet</span> resistance, from 163 Ω/sq. to 70 Ω/sq. for a 20 nm TiN film (corresponding resistivity ∼145 μΩ·cm), were achieved by addition of a postcycle Ar/N{sub 2} <span class="hlt">plasma</span> step in the PE-ALD process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APExp...7d6201S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APExp...7d6201S"><span id="translatedtitle">Hierarchical regrowth of flowerlike nanographene <span class="hlt">sheets</span> on oxygen-<span class="hlt">plasma</span>-treated carbon nanowalls</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shimoeda, Hironao; Kondo, Hiroki; Ishikawa, Kenji; Hiramatsu, Mineo; Sekine, Makoto; Hori, Masaru</p> <p>2014-04-01</p> <p>Cauliflorous nanographene <span class="hlt">sheets</span> were hierarchically regrown on the spearlike structures of carbon nanowalls (CNWs) produced by O2-<span class="hlt">plasma</span> etching. The spears on the CNWs acted as a stem for the growth of flowerlike flaky nanographene <span class="hlt">sheets</span>, where the root of the nanoflower was located at a defect or disordered site. The defects on the graphitic structures were induced by irradiation with oxygen-related radicals and ions in the O2-based <span class="hlt">plasmas</span> and acted as sites for the nucleation of flowerlike nanographene. The porous carbon nanostructures regrown after O2-<span class="hlt">plasma</span> treatment have a relatively higher surface area and are thus promising materials for electrochemical applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910026465&hterms=earth+layers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dearth%2527s%2Blayers','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910026465&hterms=earth+layers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dearth%2527s%2Blayers"><span id="translatedtitle">The lobe to <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer transition - Theory and observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schriver, D.; Ashour-Abdalla, M.; Treumann, R.; Nakamura, M.; Kistler, L. M.</p> <p>1990-01-01</p> <p>The lobe and the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer in the earth's magnetotail are regions of different <span class="hlt">plasma</span> conditions and share a common interface. The transition from the lobe to the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer is examined here using AMPTE/IRM data. When the satellite crossed from the lobe to the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer, intense narrow-banded wave bursts at 1 kHz were observed and broadband electrostatic noise (BEN) immediately followed. Simultaneous with the onset of BEN, high energy earthward streaming proton beams at more than 40 keV (more than 2700 km/s) were detected. These results are used as input into a numerical simulation to study ion beam instabilities in the PSBL.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1212467-shape-terrestrial-plasma-sheet-near-earth-magnetospheric-tail-imaged-interstellar-boundary-explorer','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1212467-shape-terrestrial-plasma-sheet-near-earth-magnetospheric-tail-imaged-interstellar-boundary-explorer"><span id="translatedtitle">Shape of the terrestrial <span class="hlt">plasma</span> <span class="hlt">sheet</span> in the near-Earth magnetospheric tail as imaged by the Interstellar Boundary Explorer</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Dayeh, M. A.; Fuselier, S. A.; Funsten, H. O.; McComas, D. J.; Ogasawara, K.; Petrinec, S. M.; Schwadron, N. A.; Valek, P.</p> <p>2015-04-11</p> <p>We present remote, continuous observations from the Interstellar Boundary Explorer of the terrestrial <span class="hlt">plasma</span> <span class="hlt">sheet</span> location back to -16 Earth radii (RE) in the magnetospheric tail using energetic neutral atom emissions. The time period studied includes two orbits near the winter and summer solstices, thus associated with large negative and positive dipole tilt, respectively. Continuous side-view images reveal a complex shape that is dominated mainly by large-scale warping due to the diurnal motion of the dipole axis. Superposed on the global warped geometry are short-time fluctuations in <span class="hlt">plasma</span> <span class="hlt">sheet</span> location that appear to be consistent with <span class="hlt">plasma</span> <span class="hlt">sheet</span> flapping andmore » possibly twisting due to changes in the interplanetary conditions. We conclude that the <span class="hlt">plasma</span> <span class="hlt">sheet</span> warping due to the diurnal motion dominates the average shape of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. Over short times, the position of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> can be dominated by twisting and flapping.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1212467','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1212467"><span id="translatedtitle">Shape of the terrestrial <span class="hlt">plasma</span> <span class="hlt">sheet</span> in the near-Earth magnetospheric tail as imaged by the Interstellar Boundary Explorer</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Dayeh, M. A.; Fuselier, S. A.; Funsten, H. O.; McComas, D. J.; Ogasawara, K.; Petrinec, S. M.; Schwadron, N. A.; Valek, P.</p> <p>2015-04-11</p> <p>We present remote, continuous observations from the Interstellar Boundary Explorer of the terrestrial <span class="hlt">plasma</span> <span class="hlt">sheet</span> location back to -16 Earth radii (R<sub>E</sub>) in the magnetospheric tail using energetic neutral atom emissions. The time period studied includes two orbits near the winter and summer solstices, thus associated with large negative and positive dipole tilt, respectively. Continuous side-view images reveal a complex shape that is dominated mainly by large-scale warping due to the diurnal motion of the dipole axis. Superposed on the global warped geometry are short-time fluctuations in <span class="hlt">plasma</span> <span class="hlt">sheet</span> location that appear to be consistent with <span class="hlt">plasma</span> <span class="hlt">sheet</span> flapping and possibly twisting due to changes in the interplanetary conditions. We conclude that the <span class="hlt">plasma</span> <span class="hlt">sheet</span> warping due to the diurnal motion dominates the average shape of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. Over short times, the position of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> can be dominated by twisting and flapping.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996PhPl....3.2041E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996PhPl....3.2041E"><span id="translatedtitle">Coupling between <span class="hlt">electron</span> <span class="hlt">plasma</span> waves in laser-<span class="hlt">plasma</span> interactions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Everett, M. J.; Lal, A.; Clayton, C. E.; Mori, W. B.; Joshi, C.; Johnston, T. W.</p> <p>1996-05-01</p> <p>A Lagrangian fluid model (cold <span class="hlt">plasma</span>, fixed ions) is developed for analyzing the coupling between <span class="hlt">electron</span> <span class="hlt">plasma</span> waves. This model shows that a small wave number <span class="hlt">electron</span> <span class="hlt">plasma</span> wave (?2,k2) will strongly affect a large wave number <span class="hlt">electron</span> <span class="hlt">plasma</span> wave (?1,k1), transferring its energy into daughter waves or sidebands at (?1+n?2,k1+nk2) in the lab frame. The accuracy of the model is checked via particle-in-cell simulations, which confirm that the energy in the mode at (?1,k1) can be completely transferred to the sidebands at (?1+n?2,k1+nk2) by the presence of the <span class="hlt">electron</span> <span class="hlt">plasma</span> mode at (?2,k2). Conclusive experimental evidence for the generation of daughter waves via this coupling is then presented using time- and wave number-resolved spectra of the light from a probe laser coherently Thomson scattered by the <span class="hlt">electron</span> <span class="hlt">plasma</span> waves generated by the interaction of a two-frequency CO2 laser with a <span class="hlt">plasma</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1989JGR....94.3495R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1989JGR....94.3495R"><span id="translatedtitle">Jovian <span class="hlt">plasma</span> <span class="hlt">sheet</span> density profile from low-frequency radio waves</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rucker, H. O.; Ladreiter, H. P.; Leblanc, Y.; Jones, D.; Kurth, W. S.</p> <p>1989-04-01</p> <p>By using planetary radio astronomy (PRA), <span class="hlt">plasma</span> wave system (PWS), and magnetometer (MAG) data from Voyager 1 and 2 (V1 and V2), essential features of the nightside Jovian <span class="hlt">plasma</span> <span class="hlt">sheet</span> are derived, and the density gradient of the corotating <span class="hlt">plasma</span> structure in the middle Jovian magnetosphere is calculated. The PRA experiment gives information about the <span class="hlt">plasma</span> wave polarization. The density profile of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> is determined using the hinge point position of the <span class="hlt">plasma</span> disk derived from MAG data, and the low-frequency cutoffs observed at three frequencies (562 Hz, 1 kHz, and 1.78 kHz) from the PWS experiment. It is shown that the hinge point position varies with the solar wind ram pressure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AnGeo..27.4131H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AnGeo..27.4131H"><span id="translatedtitle">Occurrence and location of concentrated load and generator regions observed by Cluster in the <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hamrin, M.; Norqvist, P.; Marghitu, O.; Buchert, S.; Klecker, B.; Kistler, L. M.; Dandouras, I.</p> <p>2009-11-01</p> <p>Here, and in a companion paper by Hamrin et al. (2009) [Scale size and life time of energy conversion regions observed by Cluster in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>], we investigate localized energy conversion regions (ECRs) in the Earth's <span class="hlt">plasma</span> <span class="hlt">sheet</span>. In total we have studied 151 ECRs within 660 h of <span class="hlt">plasma</span> <span class="hlt">sheet</span> data from the summer and fall of 2001 when Cluster was close to apogee at an altitude of about 15-20 RE. Cluster offers appropriate conditions for the investigation of energy conversion by the evaluation of the power density, EJ, where E is the electric field and J the current density. From the sign of the power density, we have identified more than three times as many Concentrated Load Regions (CLRs) as Concentrated Generator Regions (CGRs). We also note that the CLRs appear to be stronger. To our knowledge, these are the first in situ observations confirming the general notion of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, on the average, behaving as a load. At the same time the <span class="hlt">plasma</span> <span class="hlt">sheet</span> appears to be highly structured, with energy conversion occurring in both directions between the fields and the particles. From our data we also find that the CLRs appear to be located closer to the neutral <span class="hlt">sheet</span>, while CGRs prefer locations towards the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer (PSBL). For both CLRs and CGRs, E and J in the GSM y (cross-tail) direction dominate the total power density, even though the z contribution occasionally can be significant. The prevalence of the y-direction seems to be weaker for the CGRs, possibly related to a higher fluctuation level near the PSBL.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/183241','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/183241"><span id="translatedtitle">Structured <span class="hlt">plasma</span> <span class="hlt">sheet</span> thinning observed by Galileo and 1984-129</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Reeves, G.D.; Belian, R.D.; Fritz, T.A.</p> <p>1993-12-01</p> <p>On December 8, 1990, the Galileo spacecraft used the Earth for a gravity assist on its way to Jupiter. Its trajectory was such that is crossed geosynchronous orbit at approximately local midnight between 1900 and 2000 UT. At the same time, spacecraft 1984-129 was also located at geosynchronous orbit near local midnight. Several flux dropout events were observed when the two spacecraft were in the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> in the same local time sector. Flux dropout events are associated with <span class="hlt">plasma</span> <span class="hlt">sheet</span> thinning in the near-Earth tail during the growth phase of substorms. This period is unique in that Galileo provided a rapid radial profile of the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> while 1984-129 provided an azimuthal profile. With measurements from these two spacecraft the authors can distinguish between spatial structures and temporal changes. Their observations confirm that the geosynchronous flux dropout events are consistent with <span class="hlt">plasma</span> <span class="hlt">sheet</span> thinning which changes the spacecraft`s magnetic connection from the trapping region to the more distant <span class="hlt">plasma</span> <span class="hlt">sheet</span>. However, for this period, thinning occurred on two spatial and temporal scales. The geosynchronous dropouts were highly localized phenomena of 30 min duration superimposed on a more global reconfiguration of the tail lasting approximately 4 hours. 28 refs., 10 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/991589','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/991589"><span id="translatedtitle"><span class="hlt">Electronic</span> and Magnetic Properties of Metal-Doped BN <span class="hlt">Sheet</span>: A First-Principles Study</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhou, Yungang; Xiao-Dong, J.; Wang, Zhiguo; Xiao, Haiyan Y.; Gao, Fei; Zu, Xiaotao T.</p> <p>2010-07-21</p> <p><span class="hlt">Electronic</span> and magnetic properties of BN <span class="hlt">sheet</span> doped with 3d transition metals (Fe, Co and Ni) have been investigated using ab initio calculations. Our calculations show many interesting physical properties in metal-doped BN <span class="hlt">sheet</span>. Fe-doped BN <span class="hlt">sheet</span> is a half-metal with the magnetic moment of 2.0 ?B, and Co-doped BN <span class="hlt">sheet</span> becomes a narrow-gap semiconductor with the magnetic moment of 1.0 ?B. However, no magnetic moment is induced on Ni-doped BN <span class="hlt">sheet</span>, which has the same band gap as pristine BN <span class="hlt">sheet</span>. Furthermore, Fe atom is easy to form isolated particle on BN <span class="hlt">sheet</span>, while Ni and Co atoms are likely to form <span class="hlt">sheet</span>-supported metal nanotemplate. These results are useful for spintronics application and could help in the development of magnetic nanotructures and metallic nanotemplate at room temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19820051677&hterms=streaming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dstreaming','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19820051677&hterms=streaming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dstreaming"><span id="translatedtitle"><span class="hlt">Plasma</span> behavior during energetic <span class="hlt">electron</span> streaming events further evidence for substorm-associated magnetic reconnection</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bieber, J. W.; Stone, E. C.; Hones, E. W., Jr.; Baker, D. N.; Bame, S. J.</p> <p>1982-01-01</p> <p>A recent study showed that streaming energetic (more than 200 keV) <span class="hlt">electrons</span> in earth's magnetotail are statistically associated with southward magnetic fields and with enhancements of the AE index. It is shown here that the streaming <span class="hlt">electrons</span> characteristically are preceded by an approximately 15-minute period of tailward <span class="hlt">plasma</span> flow and followed by a dropout of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, thus demonstrating a clear statistical association between substorms and the classical signatures of magnetic reconnection and plasmoid formation. Additionally, a brief upward surge of mean <span class="hlt">electron</span> energy preceded <span class="hlt">plasma</span> dropout in several of the events studied, providing direct evidence of localized, reconnection-associated heating processes.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AIPC..691..107R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AIPC..691..107R"><span id="translatedtitle">A Gridded <span class="hlt">Electron</span> Gun for a <span class="hlt">Sheet</span> Beam Klystron</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Read, M. E.; Miram, G.; Ives, R. L.; Ivanov, V.; Krasnykh, A.</p> <p>2003-12-01</p> <p>Calabazas Creek Research, Inc.(CCR) is developing rectangular, gridded, thermionic, dispenser-cathode guns for <span class="hlt">sheet</span> beam devices. The first application is expected to be klystrons for advanced particle accelerators and colliders. The current generation of accelerators typically use klystrons with a cylindrical beam generated by a Pierce-type <span class="hlt">electron</span> gun. As RF power is pushed to higher levels, space charge forces in the <span class="hlt">electron</span> beam limit the amount of current that can be transmitted at a given voltage. The options are to increase the beam voltage, leading to problems with X-Ray shielding and modulator and power supply design, or to develop new techniques for lowering the space charge forces in the <span class="hlt">electron</span> beam. In this device, the beam has a rectangular cross section. The thickness is constrained as it would in a normal, cylindrically symmetric klystron with a Pierce gun. However, the width of the beam is many times the thickness, and the resulting cross sectional area is much larger than in the conventional device. This allows much higher current and/or a lower voltage before space charge forces become too high. The current program addresses issues related to beam formation at the emitter surface, design and implementation of shadow and control grids in a rectangular geometry. It is directed toward a robust, cost-effective, and reliable mechanical design. A prototype device will be developed that will operate at 415 kV, 250 A for an 80 MW, X-Band, <span class="hlt">sheet</span>-beam klystron. The cathode will have 100 cm2 of cathode area with an average cathode current loading of 2.5 A/cm2. For short pulse formation, the use of a grid was chosen. The gun has been designed with a combination of 2-D and 3-D codes. 2-D codes were used to determine the starting point for the electrodes to produce the compression (which is in only 1 direction.) These results showed that a very high quality beam could be achieved even in the presence of the shadow grid. 3-D results have shown that the quality can be maintained for the actual geometry. Final designs of the gun are being completed, and fabrication is expected to begin in the spring of 2003. Details of the design will be reported.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.7964P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.7964P"><span id="translatedtitle">Fast magnetic reconnection in thin current <span class="hlt">sheets</span>: effects of different current profiles and <span class="hlt">electron</span> inertia in Ohm's law.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pucci, Fulvia; Del Sarto, Daniele; Tenerani, Anna; Velli, Marco</p> <p>2015-04-01</p> <p>By examining <span class="hlt">sheets</span> with thicknesses scaling as different powers of the Lundquist number S, we previously showed (Pucci and Velli, 2014) that the growth rate of the tearing mode increases as current <span class="hlt">sheets</span> thin and, once the inverse aspect ratio reaches a scaling a/L = S-1/3, the time-scale for the instability to develop becomes of the order of the Alfvn time. That means that a fast instability sets in well before Sweet-Parker type current <span class="hlt">sheets</span> can form. In addition, such an instability produces many islands in the <span class="hlt">sheet</span>, leading to fast nonlinear evolution and most probably a turbulent disruption of the <span class="hlt">sheet</span> itself. This has fundamental implications for magnetically driven reconnection throughout the corona, and in particular for coronal heating and the triggering of coronal mass ejections. Here we extend the study of reconnection instabilities to magnetic fields of grater complexity, displaying different current structures such as, for example, multiple or asymmetric current layers. We also consider the possibility of a ?' dependence on wave-number k-p for different values of p, studying analogies and variations of the trigger scaling relation a/L ~ S-1/3 with respect to the Harris current <span class="hlt">sheet</span> equilibrium. At large Lundquist numbers in typical Heliospheric <span class="hlt">plasmas</span> kinetic effects become more important in Ohm's law: we consider the effects of <span class="hlt">electron</span> skin depth reconnection, showing that we can define a trigger relation similar to the resistive case. The results are important to the transition to fast reconnection in the solar corona, solar wind, magnetosphere as well as laboratory <span class="hlt">plasmas</span>. F. Pucci and M. Velli, "Reconnection of quasi-singular current <span class="hlt">sheets</span>: the 'ideal" tearing mode" ApJ 780:L19, 2014.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21502826','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21502826"><span id="translatedtitle"><span class="hlt">Electron</span> capture rates in a <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sawyer, R. F.</p> <p>2011-06-15</p> <p>A new general expression is derived for nuclear <span class="hlt">electron</span> capture rates within dense <span class="hlt">plasmas</span>. Its qualitative nature leads us to question some widely accepted assumptions about how to calculate the effects of the <span class="hlt">plasma</span> on the rates. A perturbative evaluation, though not directly applicable to the strongly interacting case, appears to bear out these suspicions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JGRA..116.5207Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JGRA..116.5207Y"><span id="translatedtitle">RCM-E simulation of ion acceleration during an idealized <span class="hlt">plasma</span> <span class="hlt">sheet</span> bubble injection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, J.; Toffoletto, F. R.; Wolf, R. A.; Sazykin, S.</p> <p>2011-05-01</p> <p>In this paper, we investigate the role of <span class="hlt">plasma</span> <span class="hlt">sheet</span> bubbles in the ion flux variations at geosynchronous orbit during substorm injections by using the Rice Convection Model with an equilibrated magnetic field model (RCM-E). The bubble is initiated in the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> with a localized reduction in entropy parameter PV5/3 following a substorm growth phase. In the expansion phase, characteristic features of substorm injections are reproduced; that is, there is a prominent dispersionless flux increase for energetic protons (>40 keV) and a flux decrease for lower-energy protons near midnight geosynchronous orbit while there is dispersive flux enhancement near the dusk sector. We find that the injection boundary is well coincident with the earthward boundary of the bubble, inside which the depletion of <span class="hlt">plasma</span> content causes the magnetic field dipolarization, and in return, the magnetic field collapse energizes particles and alters the drift paths dramatically. Our results also show that a high-PV5/3 island is pushed ahead of the fast earthward propagating bubble, and a dipolarization front forms between them. Within the high-PV5/3 island, the diamagnetic effect makes the <span class="hlt">plasma</span> pressure increase and the strength of the magnetic field decrease to a local minimum. We suggest that <span class="hlt">plasma</span> <span class="hlt">sheet</span> bubbles are elementary vehicles of substorm time particle injections from the main <span class="hlt">plasma</span> <span class="hlt">sheet</span> to the inner magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSM44B..01R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSM44B..01R"><span id="translatedtitle">Thermal Structure and Dynamics in Supra-arcade Downflows and Flare <span class="hlt">Plasma</span> <span class="hlt">Sheets</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reeves, K.; Hanneman, W.; Freed, M.; McKenzie, D. E.</p> <p>2014-12-01</p> <p>During a long duration solar flare, a hot <span class="hlt">plasma</span> <span class="hlt">sheet</span> is commonly formed above the flare loops. Often produced within this <span class="hlt">sheet</span> are down-flowing voids referred to as supra-arcade downflows, thought to be the products of a patchy reconnection process. Models differ on the question of whether the downflows should be hotter than the surrounding <span class="hlt">plasma</span> or not. We use imaging data from Hinode/XRT and SDO/AIA to determine the thermal structure of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and downflows. We find that the temperatures of the <span class="hlt">plasma</span> within the downflows are either roughly the same as or lower than the surrounding fan <span class="hlt">plasma</span>. This result implies that a mechanism for forming the voids that involves a sunward directed hydrodynamic shock pattern combined with perpendicular magnetic shock is unlikely. Additionally, we use the high cadence AIA data to trace the velocity fields in these regions through the use of a local correlation tracking algorithm. Through these measurements, we can determine areas of diverging velocity fields, as well as velocity shear fields and correlate them with temperature changes in order to understand the heating mechanisms in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. This work is supported by under contract SP02H1701R from Lockheed-Martin to SAO, contract NNM07AB07C from NASA to SAO and NASA grant numbers NNX13AG54G and NNX14AD43G</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004APS..DPPJP1083G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004APS..DPPJP1083G"><span id="translatedtitle">Spectroscopic Diagnostics of Electric Fields in the <span class="hlt">Plasma</span> of Current <span class="hlt">Sheets</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gavrilenko, Valeri; Kyrie, Natalya P.; Frank, Anna G.; Oks, Eugene</p> <p>2004-11-01</p> <p>Spectroscopic measurements of electric fields (EFs) in current <span class="hlt">sheet</span> <span class="hlt">plasmas</span> were performed in the CS-3D device. The device is intended to study the evolution of current <span class="hlt">sheets</span> and the magnetic reconnection phenomena. We used the broadening of spectral lines (SLs) of HeII ions for diagnostics of EFs in the current <span class="hlt">sheet</span> middle plane, and the broadening of SLs of HeI atoms for detection of EFs in the current <span class="hlt">sheet</span> peripheral regions. For detection of EFs in current <span class="hlt">sheet</span> <span class="hlt">plasma</span>, we used SLs of HeII ions at 468.6; 320.3 and 656.0 nm, as well as SLs of HeI atoms at 667.8; 587.6; 492.2 and 447.1 nm. The latter two lines are of a special interest since their profiles include the dipole-forbidden components along with the allowed components. The experimental data have been analyzed by using the numerical calculations based on the Model Microfield Method. The maximum <span class="hlt">plasma</span> density in the middle of the <span class="hlt">sheet</span> was in the range (2-8) 10^16 cm-3, the density in the peripheral regions was (1-2)10^15 cm-3, and the strength of the quasi-one-dimensional anomalous electric fields in the peripheral regions reached the value of 100 kV/cm. Supported by CRDF, grant RU-P1-2594-MO-04; by the RFBR, grant 03-02-17282; and by the ISTC, project 2098.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...807..159T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...807..159T"><span id="translatedtitle">A Theoretical Model of a Thinning Current <span class="hlt">Sheet</span> in the Low-? <span class="hlt">Plasmas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Takeshige, Satoshi; Takasao, Shinsuke; Shibata, Kazunari</p> <p>2015-07-01</p> <p>Magnetic reconnection is an important physical process in various explosive phenomena in the universe. In previous studies, it was found that fast reconnection takes place when the thickness of a current <span class="hlt">sheet</span> becomes on the order of a microscopic length such as the ion Larmor radius or the ion inertial length. In this study, we investigated the pinching process of a current <span class="hlt">sheet</span> by the Lorentz force in a low-? <span class="hlt">plasma</span> using one-dimensional magnetohydrodynamics (MHD) simulations. It is known that there is an exact self-similar solution for this problem that neglects gas pressure. We compared the non-linear MHD dynamics with the analytic self-similar solution. From the MHD simulations, we found that with the gas pressure included the implosion process deviates from the analytic self-similar solution as t\\to {t}0, where t0 is the explosion time when the thickness of a current <span class="hlt">sheet</span> of the analytic solution becomes 0. We also found that a pair of MHD fast-mode shocks is generated and propagates after the formation of the pinched current <span class="hlt">sheet</span> as t\\to {t}0. On the basis of the Rankine-Hugoniot relations, we derived the scaling law of the physical quantities with respect to the initial <span class="hlt">plasma</span> beta in the pinched current <span class="hlt">sheet</span>. Our study could help us estimate the physical quantities in the pinched current <span class="hlt">sheet</span> formed in a low-? <span class="hlt">plasma</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AASP....3...53S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AASP....3...53S"><span id="translatedtitle">Vortex and ULF wave structures in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> of the Earth magnetosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saliuk, D. A.; Agapitov, O. V.</p> <p>2013-08-01</p> <p>We studied the ULF wave packet propagation in the Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> making use of the magnetic field measurements from FGM detector and <span class="hlt">plasma</span> properties from CORRAL detector aboard the Interball-Tail spacecraft. The MHD vortex structures were observed simultaneously with the Pc5 ULF waves. The vortex spatial scale was found to be about 1200-3600 km and the velocity is 4-16 km/s transverse to the background magnetic field. We studied numerically the dynamics of the initial vortex perturbations in the <span class="hlt">plasma</span> system with parameters observed in the Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span>. The system with the vector nonlinearity was processed making use of the full reduction scheme. The good agreement of the experimental value of the vortex structure velocity with numerical results was obtained. The velocity was found to be close to the local <span class="hlt">plasma</span> drift velocity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19990103021&hterms=McCarthy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DMcCarthy%252C%2BR','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19990103021&hterms=McCarthy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DMcCarthy%252C%2BR"><span id="translatedtitle">Observations of Substorms from the Auroral Ionosphere to the Distant <span class="hlt">Plasma</span> <span class="hlt">Sheet</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Parks, G.; Brittnacher, M.; Chen, L.; Chua, D.; Elsen, R.; Fillingim, M.; McCarthy, M.; Germany, G.; Spann, J.</p> <p>1998-01-01</p> <p>We have been studying how substorms work by examining the global polar Ultraviolet Imager (UVI) images in correlation with observations from the ground, interplanetary space and the geomagnetic tail between 10-20 earth radii. One of the objectives of our study is to better understand the connection among many complex phenomena going on close to Earth and those in the distant <span class="hlt">plasma</span> <span class="hlt">sheet</span>. We have studied, for example, how the aurora[ and polar cap boundaries at different local times behave in relation to variations observed in the solar wind and <span class="hlt">plasma</span> <span class="hlt">sheet</span> during substorms. Preliminary results indicate that the polar cap and auroral oval boundaries expand and contract in a complicated but systematic way. These variations are correlated to solar wind parameters, and thinning and recovery phenomena in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. These results will be presented and interpreted in terms of directly driven and/or unloading substorm processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5727707','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5727707"><span id="translatedtitle">Characteristics of ion flow in the quiet state of the inner <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Angelopoulos, V.; Kennel, C.F.; Coroniti, F.V.; Pellat, R.; Kivelson, M.G.; Walker, R.J.; Russell, C.T. ); Spence, H.E. ); Baumjohann, W. ); Feldman, W.C.; Gosling, J.T. )</p> <p>1993-08-20</p> <p>The authors model the properties of the ion flow in the high [beta][sub i], inner <span class="hlt">plasma</span> <span class="hlt">sheet</span>, during periods when geomagnetic activity is relatively low. They adopt the approach that the <span class="hlt">plasma</span> <span class="hlt">sheet</span> can be modeled in terms of bursty bulk flows (BBF's), irrespective of the auroral electrojet index. They then model the average flow pattern in the inner <span class="hlt">plasma</span> <span class="hlt">sheet</span> after the obvious BBF events have been removed from the data. The average flow properties found do not represent the instantaneous flow fields however, as there are large variances observed, even in the non-BBF part of the flow field. They are able to generate the same average flow patterns with their model, taking into account flow due to corotation, crossed field flow, and diamagnetic drift, as the T87 model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19840051523&hterms=technologie&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dtechnologie','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19840051523&hterms=technologie&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dtechnologie"><span id="translatedtitle">Energetic (greater than 100 keV) O(+) ions in the <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ipavich, F. M.; Galvin, A. B.; Gloeckler, G.; Hovestadt, D.; Klecker, B.; Scholer, M.</p> <p>1984-01-01</p> <p>The first measurements of very energetic (112 - 157 keV) O(+) ions in the earth's magnetosphere are presented. The observations were made with the UMd/MPE ULECA sensor on ISEE-1 on 5 March 1981 at geocentric distances approximately 20 R(E) in the earth's magnetotail. During this time period an Energetic Storm Particle event was observed by the nearly identical sensor on the ISEE-3 spacecraft, located approximately 250 R(E) upstream of the earth's magnetosphere. The ISEE-1 sensor observed a similar temporal profile except for several sharp intensity enhancements, corresponding to substorm recoveries during which the <span class="hlt">plasma</span> <span class="hlt">sheet</span> engulfed the spacecraft. During these <span class="hlt">plasma</span> <span class="hlt">sheet</span> encounters we observe O(+)/H(+) abundance ratios, at approximately 130 kev, as large as 0.35. In between <span class="hlt">plasma</span> <span class="hlt">sheet</span> encounters the O(+)/H(+) ratio at this energy is consistent with zero.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900054441&hterms=mond&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmond','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900054441&hterms=mond&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmond"><span id="translatedtitle">Ballooning instability of the earth's <span class="hlt">plasma</span> <span class="hlt">sheet</span> region in the presence of parallel flow</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lakhina, G. S.; Hameiri, E.; Mond, M.</p> <p>1990-01-01</p> <p>Stability of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer against the ballooning mode instability is investigated. The equilibrium state of a two-dimensional <span class="hlt">plasma</span> <span class="hlt">sheet</span> configuration with parallel sheared flow is modeled. This equilibrium is shown to be ballooning unstable when delta-W is not positive definite, where delta-W is the potential energy. The eigenmode structure of the ballooning mode is found by imposing the boundary conditions that the waves are totally reflected from the ionosphere, and that no waves are coming in from infinity. The eigenmode structure of the unstable balloning modes is highly oscillatory, extending beyond about 100 R(E). The ballooning modes are thus a possible candidate for explaining the MHD waves and other dynamical events observed in the magnetotail by ISEE 3 and other spacecraft.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21443567','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21443567"><span id="translatedtitle">Suprathermal <span class="hlt">plasma</span> flows in current <span class="hlt">sheets</span> formed in two- and three-dimensional magnetic configurations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kyrie, N. P.; Markov, V. S.; Frank, A. G.</p> <p>2010-04-15</p> <p>Dynamics of the thermal and directed motions of argon <span class="hlt">plasma</span> ions in current <span class="hlt">sheets</span> formed in various magnetic configurations was investigated experimentally Measurements in three-dimensional magnetic configurations with an X line were carried out for the first time. The results of these measurements were compared with the data obtained in experiments with two-dimensional magnetic configurations. The ion temperature and the energies and velocities of directed <span class="hlt">plasma</span> flows within the current <span class="hlt">sheet</span> were determined by analyzing the shapes of argon ion spectral lines broadened due to the Doppler effect. It is found that, under the given experimental conditions, the axial magnetic field does not affect the ion temperature and <span class="hlt">plasma</span> acceleration in the <span class="hlt">sheet</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999PhPl....6.1649O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999PhPl....6.1649O"><span id="translatedtitle">Development of <span class="hlt">plasma</span> cathode <span class="hlt">electron</span> guns</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oks, Efim M.; Schanin, Peter M.</p> <p>1999-05-01</p> <p>The status of experimental research and ongoing development of <span class="hlt">plasma</span> cathode <span class="hlt">electron</span> guns in recent years is reviewed, including some novel upgrades and applications to various technological fields. The attractiveness of this kind of e-gun is due to its capability of creating high current, broad or focused beams, both in pulsed and steady-state modes of operation. An important characteristic of the <span class="hlt">plasma</span> cathode <span class="hlt">electron</span> gun is the absence of a thermionic cathode, a feature which leads to long lifetime and reliable operation even in the presence of aggressive background gas media and at fore-vacuum gas pressure ranges such as achieved by mechanical pumps. Depending on the required beam parameters, different kinds of <span class="hlt">plasma</span> discharge systems can be used in <span class="hlt">plasma</span> cathode <span class="hlt">electron</span> guns, such as vacuum arcs, constricted gaseous arcs, hollow cathode glows, and two kinds of discharges in crossed EB fields: Penning and magnetron. At the present time, <span class="hlt">plasma</span> cathode <span class="hlt">electron</span> guns provide beams with transverse dimension from fractional millimeter up to about one meter, beam current from microamperes to kiloamperes, beam current density up to about 100 A/cm2, pulse duration from nanoseconds to dc, and <span class="hlt">electron</span> energy from several keV to hundreds of keV. Applications include <span class="hlt">electron</span> beam melting and welding, surface treatment, <span class="hlt">plasma</span> chemistry, radiation technologies, laser pumping, microwave generation, and more.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhDT.......230C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhDT.......230C"><span id="translatedtitle"><span class="hlt">Plasma</span> interaction with <span class="hlt">electron</span>-emitting surfaces</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Campanell, Michael D.</p> <p></p> <p><span class="hlt">Electron</span> emission from surfaces occurs in many <span class="hlt">plasma</span> systems. Several types including secondary, thermionic and photon-induced emissions are intense under certain conditions. Understanding the effects of emission on the "sheaths" that govern <span class="hlt">plasma</span>-surface interaction is important. This dissertation predicts some emitting sheath phenomena that were not reported in past studies. For example, most previous theoretical models assumed that an emitting sheath potential is always negative and that ions always accelerate into the wall. We show when the emission is intense that the sheath potential can become positive, fundamentally changing how the <span class="hlt">plasma</span> and wall interact. In this "inverse sheath" state, ions are repelled, suggesting for instance that (a) no presheath exists in the <span class="hlt">plasma</span> interior, (b) emitting walls could be used in applications to stop sputtering. Another topic considered is the "transit" of emitted <span class="hlt">electrons</span> across the <span class="hlt">plasma</span> to other surfaces, which is possible in low collisionality <span class="hlt">plasma</span> systems. When transit occurs, the flux balance is a complex global problem where the sheaths at opposite surfaces are coupled through their exchange of emitted <span class="hlt">electrons</span>. We also show that secondary emission can trigger a variety of sheath instability phenomena that change the state of the <span class="hlt">plasma</span>-wall system or cause oscillations preventing steady state. Lastly, we analyze a mechanism where emitted <span class="hlt">electrons</span> return to the same surface and knock out secondaries, which return and knock out more secondaries, etc., feedback amplifying the emission intensity. The four phenomena will be analyzed theoretically and verified with particle-in-cell simulations: (a) inverse sheath, (b) sheath coupling via transiting <span class="hlt">electrons</span>, (c) sheath instabilities, (d) returning <span class="hlt">electron</span> amplification. Consequences of these processes on the sheath potentials, wall heating, loss rate of charge, and cross field transport (near-wall conductivity) are discussed throughout. Possible implications are suggested for fusion machines, <span class="hlt">plasma</span> propulsion engines, probes, dusty <span class="hlt">plasmas</span>, RF discharges, and surfaces in space.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009PPCF...51c5012Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009PPCF...51c5012Z"><span id="translatedtitle">Current <span class="hlt">sheets</span> during spontaneous reconnection in a current-carrying fusion <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zuin, M.; Vianello, N.; Spolaore, M.; Antoni, V.; Bolzonella, T.; Cavazzana, R.; Martines, E.; Serianni, G.; Terranova, D.</p> <p>2009-03-01</p> <p>An analysis of <span class="hlt">plasma</span> dynamics during impulsive magnetic reconnection events in the RFX-mod reversed field pinch (RFP) is performed by means of a large set of magnetic in-vessel coils and of an insertable edge probe, equipped with a matrix of electrostatic (Langmuir) and magnetic probes. It is observed that reconnection of field lines, which leads to a global reconfiguration of the magnetic topology (relaxation), is associated with the rapid formation of a strongly localized magnetic perturbation characterized by a main m = 0 periodicity, due to enhanced dynamo modes activity. Soon after its formation, the m = 0 perturbation is observed to move in the toroidal direction and is shown to correspond to a poloidal current <span class="hlt">sheet</span>, whose existence was predicted by three-dimensional MHD numerical simulations on RFP sustainment through magnetic reconnection processes. A reconstruction of the current density structure associated with the rotating magnetic perturbation is performed by means of the insertable probe, along with an investigation of the large induced modification of <span class="hlt">electron</span> temperature, density and <span class="hlt">plasma</span> velocity shear at the edge.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21251576','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21251576"><span id="translatedtitle"><span class="hlt">Electronic</span> Broadening operator for relativistic <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Meftah, M. T.; Naam, A.</p> <p>2008-10-22</p> <p>In this work we review some aspects of the semiclassical dipole impact approximation for isolated ion lines in relativistic <span class="hlt">plasma</span>. Mainly we focuss our work on the collision operator for relativistic <span class="hlt">electrons</span>. In this case, the <span class="hlt">electron</span> trajectory around a positive charge in the <span class="hlt">plasma</span> differs drastically from those known earlier as hyperbolic. The effect of this difference on the collision operator is discussed with respect the various <span class="hlt">plasma</span> conditions. Some theoretical and practical aspects of lines -shape calculations are discussed. Detailed calculations are performed for the collision operator in the semiclassical (dipole) impact approximation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ZNatA..70..244D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ZNatA..70..244D"><span id="translatedtitle">Dense <span class="hlt">Electron</span>-Positron Pair <span class="hlt">Plasma</span> Expansion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Djebli, Mourad</p> <p>2015-10-01</p> <p>The expansion of an <span class="hlt">electron</span>-positron <span class="hlt">plasma</span> is studied based on quantum hydrodynamical equations for two fluids. The quasi-neutral expansion, depicted through the quantum screening distance, is investigated numerically when the annealing processes is very slow. It was found that the pair <span class="hlt">plasma</span> behaves as a single fluid with a front expansion velocity that depends on the density and degenerate parameters. Faster expansion results from the existence of exchange-correlation potential, which is enhanced in high-density <span class="hlt">plasma</span>. The present investigation may be useful in understanding the expansion of a dense <span class="hlt">plasma</span> produced by the interaction between high-energy laser and solid targets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005PhPl...12g2508K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005PhPl...12g2508K"><span id="translatedtitle">Recombinative <span class="hlt">plasma</span> in <span class="hlt">electron</span> runaway discharge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kuznetsov, Yu. K.; Galvão, R. M. O.; Usuriaga, O. C.; Krasheninnikov, S. I.; Soboleva, T. K.; Tsypin, V. S.; Fonseca, A. M. M.; Ruchko, L. F.; Sanada, E. K.</p> <p>2005-07-01</p> <p>Cold recombinative <span class="hlt">plasma</span> is the basic feature of the new regime of runaway discharges recently discovered in the Tokamak Chauffage Alfvén Brésilien tokamak [R. M. O. Galvão et al., <span class="hlt">Plasma</span> Phys. Controlled Fusion 43, 1181 (2001)]. With low <span class="hlt">plasma</span> temperature, the resistive <span class="hlt">plasma</span> current and primary Dreicer process of runaway generation are strongly suppressed at the stationary phase of the discharge. In this case, the runaway avalanche, which has been recently recognized as a novel important mechanism for runaway <span class="hlt">electron</span> generation in large tokamaks, such as International Thermonuclear Experimental Reactor, during disruptions, and for electric breakdown in matter, is the only mechanism responsible for toroidal current generation and can be easily observed. The measurement of <span class="hlt">plasma</span> temperature by the usual methods is a difficult task in fully runaway discharges. In the present work, various indirect evidences for low-temperature recombinative <span class="hlt">plasma</span> are presented. The direct observation of recombinative <span class="hlt">plasma</span> is obtained as <span class="hlt">plasma</span> detachment from the limiter. The model of cold recombinative <span class="hlt">plasma</span> is also supported by measurements of <span class="hlt">plasma</span> density and Hα emission radial profiles, analysis of time variations of these parameters due to the relaxation instability, estimations of <span class="hlt">plasma</span> resistivity from voltage spikes, and energy and particle balance calculations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999AIPC..498..336P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999AIPC..498..336P"><span id="translatedtitle">Proton beam-<span class="hlt">electron</span> <span class="hlt">plasma</span> interactions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pollock, R. E.; Ellsworth, Jennifer; Muterspaugh, M. W.; Todd, D. S.</p> <p>1999-12-01</p> <p>Stored, cooled proton beams of 200 MeV with intensities up to 3 mA pass along the axis of a Penning-Malmberg trap containing a nonneutral <span class="hlt">plasma</span> of 1010 <span class="hlt">electrons</span>. The <span class="hlt">plasma</span> is maintained in a warmed steady state by injecting energy and angular momentum; the elevated temperature giving weak ionization to replenish lost <span class="hlt">electrons</span>. Comparing charge density wave velocity with diocotron mode frequency gives continual non-destructive monitoring of <span class="hlt">plasma</span> radius and density. The beam is observed to cause an increase in <span class="hlt">plasma</span> radius indicating a torquing mechanism not yet understood. The effect is weakly sensitive to shifts in beam position or angle. Monitoring power input shows either "cooling" (increased <span class="hlt">electron</span> loss rate) or heating depending on regulation method. Extension of these studies to higher containment fields will be described.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21210370','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21210370"><span id="translatedtitle">Proton beam-<span class="hlt">electron</span> <span class="hlt">plasma</span> interactions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pollock, R. E.; Ellsworth, Jennifer; Muterspaugh, M. W.; Todd, D. S.</p> <p>1999-12-10</p> <p>Stored, cooled proton beams of 200 MeV with intensities up to 3 mA pass along the axis of a Penning-Malmberg trap containing a nonneutral <span class="hlt">plasma</span> of 10{sup 10} <span class="hlt">electrons</span>. The <span class="hlt">plasma</span> is maintained in a warmed steady state by injecting energy and angular momentum; the elevated temperature giving weak ionization to replenish lost <span class="hlt">electrons</span>. Comparing charge density wave velocity with diocotron mode frequency gives continual non-destructive monitoring of <span class="hlt">plasma</span> radius and density. The beam is observed to cause an increase in <span class="hlt">plasma</span> radius indicating a torquing mechanism not yet understood. The effect is weakly sensitive to shifts in beam position or angle. Monitoring power input shows either 'cooling' (increased <span class="hlt">electron</span> loss rate) or heating depending on regulation method. Extension of these studies to higher containment fields will be described.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060009468&hterms=Current+events&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DCurrent%2Bevents','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060009468&hterms=Current+events&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DCurrent%2Bevents"><span id="translatedtitle">Dynamic Harris current <span class="hlt">sheet</span> thickness from Cluster current density and <span class="hlt">plasma</span> measurements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Thompson, S. M.; Kivelson, M. G.; Khurana, K. K.; McPherron, R. L.; Weygand, J. M.; Balogh, A.; Reme, H.; Kistler, L. M.</p> <p>2005-01-01</p> <p>We use the first accurate measurements of current densities in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> to calculate the half-thickness and position of the current <span class="hlt">sheet</span> as a function of time. Our technique assumes a Harris current <span class="hlt">sheet</span> model, which is parameterized by lobe magnetic field B(o), current <span class="hlt">sheet</span> half-thickness h, and current <span class="hlt">sheet</span> position z(sub o). Cluster measurements of magnetic field, current density, and <span class="hlt">plasma</span> pressure are used to infer the three parameters as a function of time. We find that most long timescale (6-12 hours) current <span class="hlt">sheet</span> crossings observed by Cluster cannot be described by a static Harris current <span class="hlt">sheet</span> with a single set of parameters B(sub o), h, and z(sub o). Noting the presence of high-frequency fluctuations that appear to be superimposed on lower frequency variations, we average over running 6-min intervals and use the smoothed data to infer the parameters h(t) and z(sub o)(t), constrained by the pressure balance lobe magnetic field B(sub o)(t). Whereas this approach has been used in previous studies, the spatial gnuhen& now provided by the Cluster magnetometers were unavailable or not well constrained in earlier studies. We place the calculated hdf&cknessa in a magnetospheric context by examining the change in thickness with substorm phase for three case study events and 21 events in a superposed epoch analysis. We find that the inferred half-thickness in many cases reflects the nominal changes experienced by the <span class="hlt">plasma</span> <span class="hlt">sheet</span> during substorms (i.e., thinning during growth phase, thickening following substorm onset). We conclude with an analysis of the relative contribution of (Delta)B(sub z)/(Delta)X to the cross-tail current density during substorms. We find that (Delta)B(sub z)/(Delta)X can contribute a significant portion of the cross-tail c m n t around substorm onset.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6008309','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6008309"><span id="translatedtitle">An <span class="hlt">electron</span> gun with a <span class="hlt">plasma</span> emitter</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gruzdev, V.A.; Kreindel', Y.E.; Rempe, N.G.; Troyan, O.E.</p> <p>1985-01-01</p> <p>This paper describes a continuous-running <span class="hlt">electron</span> gun which has a <span class="hlt">plasma</span> emitter that is based on a reflective arc discharge in a cold hollow cathode, which provides an <span class="hlt">electron</span> beam carrying a current of 1 A. The beam current can be regulated smoothly from 1 mA to 1 A by varying the potential of the emitter cathode.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21277305','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21277305"><span id="translatedtitle">Nonlinear interaction of <span class="hlt">electron</span> <span class="hlt">plasma</span> waves with <span class="hlt">electron</span> acoustic waves in <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chakrabarti, Nikhil</p> <p>2009-07-15</p> <p>An analysis of interaction between two temperature <span class="hlt">electron</span> species in the presence of static neutralizing ion background is presented. It is shown that <span class="hlt">electron</span> <span class="hlt">plasma</span> waves can nonlinearly interact with <span class="hlt">electron</span> acoustic wave in a time scale much longer than {omega}{sub p}{sup -1}, where {omega}{sub p} is <span class="hlt">electron</span> <span class="hlt">plasma</span> frequency. A set of coupled nonlinear differential equations is shown to exist in such a scenario. Propagating soliton solutions are demonstrated from these equations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JGRA..118.3323K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JGRA..118.3323K"><span id="translatedtitle">Substorm-associated explosive magnetic field stretching near the earthward edge of the <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kozelova, T. V.; Kozelov, B. V.</p> <p>2013-06-01</p> <p>report a detailed analysis of explosive local magnetic field line stretching just before dipolarization observed by one of Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellites during the pseudo-breakup followed by local substorm of 6 January 2008. At the end of the substorm growth phase, this satellite (THEMIS-C) was located at r ~ 6.3 RE near the convection boundary of 10 keV <span class="hlt">electrons</span>. Penetration of the hot <span class="hlt">electron</span> <span class="hlt">plasma</span> <span class="hlt">sheet</span> to the region of trapped energetic ions was a precondition for the substorm onset in the premidnight sector. Observed oscillations of fields and particles with period 50-60 s are consistent with the ballooning mode in the near-Earth magnetotail and with the near-Earth initiation current disruption model. Basing on the simple line-current model, the explosive stretching and following dipolarization observed by THEMIS-C satellite are interpreted as a manifestation of the magnetospheric generator of the 3-D meridional current system with the driving electric field in the meridional direction during nonlinear growth of ballooning instability when non-MHD processes are also turning on.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19830065820&hterms=technologie&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dtechnologie','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19830065820&hterms=technologie&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dtechnologie"><span id="translatedtitle">Energetic particles in the vicinity of a possible neutral line in the <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Moebius, E.; Scholer, M.; Hovestadt, D.; Paschmann, G.; Gloeckler, G.</p> <p>1983-01-01</p> <p>Combined <span class="hlt">plasma</span>, magnetic field, and energetic particle data obtained from ISEE-1 in the geomagnetic tail during two successive energetic particle burst events are presented. The behavior of protons with energies of more than about 100 keV is very different from that of the 30-100 keV protons which represent the suprathermal tail of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> distribution. The more energetic ions appear on a time scale of several minutes following a northward turning of the tail magnetic field. At about the same time the <span class="hlt">plasma</span> measurements show a velocity of about 200 km/s in the tailward direction. From these results, it is argued that two successive magnetic neutral lines are created well within the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and move close to the satellite position in the earthward direction. The extent of the neutral line is then limited to the dusk side of the tail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFMSM52B..09Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFMSM52B..09Z"><span id="translatedtitle">Auroral Poleward Boundary Intensifications and Modes of Energy Transport in the <span class="hlt">Plasma</span> <span class="hlt">Sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zesta, E.; Lyons, L.; Donovan, E.; Frey, H. U.; Nagai, T.</p> <p>2001-12-01</p> <p>Auroral poleward boundary intensifications (PBIs) have an auroral signature in ground meridional scanning photometer (MSP) data that appears as an increase in intensity at or near the magnetic separatrix. This increase is often seen to extend equatorward through the ionospheric mapping of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. PBIs are also associated with fast flows in the tail <span class="hlt">plasma</span> <span class="hlt">sheet</span> and are thus important to <span class="hlt">plasma</span> <span class="hlt">sheet</span> dynamics. We have recently used simultaneous auroral observations from the CANOPUS MSPs and either the Freja UV imager or the CANOPUS Gillam all-sky imager (ASI) to investigate the two-dimensional structure of auroral intensifications near the poleward boundary of the oval. We found that equatorward extending PBIs are either north-south aligned structures or east-west arcs that mostly propagate equatorward, but we have not been able to determine without doubt which type is the most prevalent. The different two-dimensional orientations for equatorward extending PBIs suggests that they may be the auroral footprint of two major modes of energy transfer in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>: multiple, narrow, earthward fast-flow channels (associated with the north-south structures) and sequences of azimuthally broad and primarily earthward propagating phase fronts initiating near the separatrix (associated with the east-west arcs). We test this hypothesis by combining data from the CANOPUS MSPs, the all-sky imagers of the newly installed NORSTAR array in northern Canada which cover the poleward boundary of the auroral oval, auroral images from the IMAGE spacecraft, and magnetic field and <span class="hlt">plasma</span> data from the Geotail spacecraft. We have identified a number of events from early 2001 when Geotail was in the midtail <span class="hlt">plasma</span> <span class="hlt">sheet</span> and seek to answer the following questions: a) Are PBI structures observed at one location associated with structures which simultaneously cover many hours of local time on the nightside, b) Are all north-south PBI structures associated with narrow channels of fast flows in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, and c) Are the east-west PBI structures also associated with fast flows or with some other dynamic structure in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>? Finally, we use events with overlapping images from both the ground ASIs and the spacecraft imager to relate the two-dimensional structure seen with high spatial resolution on the ground to the much larger spatial scale structure observable from the spacecraft.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19740053790&hterms=immersion&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dimmersion','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19740053790&hterms=immersion&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dimmersion"><span id="translatedtitle">Lunar dayside <span class="hlt">plasma</span> <span class="hlt">sheet</span> depletion - Inference from magnetic observations. [lunar immersion in geomagnetic tail</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schubert, G.; Lichtenstein, B. R.; Russell, C. T.; Coleman, P. J., Jr.; Smith, B. F.; Colburn, D. S.; Sonett, C. P.</p> <p>1974-01-01</p> <p>The existence of a day-side lunar cavity in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, showing some depletion of <span class="hlt">plasma</span>, has been inferred from cavity-associated magnetic characteristics observed by orbital and surface lunar magnetometers. These characteristics include a day-side enhancement in the mean magnetic field and day-side levels of amplification of eddy current induced magnetic field fluctuations typical of cavity confinement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPD....4430404R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPD....4430404R"><span id="translatedtitle">Thermal Structure of Supra-arcade Downflows and Flare <span class="hlt">Plasma</span> <span class="hlt">Sheets</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reeves, Kathy; Hanneman, W.; McKenzie, D. E.</p> <p>2013-07-01</p> <p>We use Hinode/XRT and SDO/AIA data to determine the thermal structure of supra arcade downflows as well as the surrounding <span class="hlt">plasma</span> <span class="hlt">sheet</span>. Using the multiple filters and broad temperature coverage provided by the combination of these two telescopes, we construct DEMs in the fan <span class="hlt">plasma</span> and the supra-arcade downflows. Several models have indicated that the <span class="hlt">plasma</span> inside the supra-arcade downflows should be significantly hotter than the surrounding <span class="hlt">plasma</span>, but about an order of magnitude less dense. However, we find that the temperatures of the <span class="hlt">plasma</span> within the downflows are either roughly the same as or lower than the surrounding fan <span class="hlt">plasma</span>, with only one exception. We also compare the thermal structure of the supra-arcade <span class="hlt">plasma</span> with calculations of the divergence of the velocity of the <span class="hlt">plasma</span> in the <span class="hlt">sheet</span> in order to locate evidence of adiabatic cooling and heating. The velocity fields are calculated using local correlation tracking applied to high-resolution sequences of AIA images. We find preliminary evidence that diverging velocity fields are cooler and less dense than the surrounding <span class="hlt">plasma</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22086320','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22086320"><span id="translatedtitle">RICHTMYER-MESHKOV-TYPE INSTABILITY OF A CURRENT <span class="hlt">SHEET</span> IN A RELATIVISTICALLY MAGNETIZED <span class="hlt">PLASMA</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Inoue, Tsuyoshi</p> <p>2012-11-20</p> <p>The linear stability of a current <span class="hlt">sheet</span> that is subject to an impulsive acceleration due to shock passage with the effect of a guide magnetic field is studied. We find that a current <span class="hlt">sheet</span> embedded in relativistically magnetized <span class="hlt">plasma</span> always shows a Richtmyer-Meshkov-type instability, while the stability depends on the density structure in the Newtonian limit. The growth of the instability is expected to generate turbulence around the current <span class="hlt">sheet</span>, which can induce the so-called turbulent reconnection, the rate of which is essentially free from <span class="hlt">plasma</span> resistivity. Thus, the instability can be applied as a triggering mechanism for rapid magnetic energy release in a variety of high-energy astrophysical phenomena such as pulsar wind nebulae, gamma-ray bursts, and active galactic nuclei, where the shock wave is thought to play a crucial role.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19970016593&hterms=plasma+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dplasma%2Benergy','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19970016593&hterms=plasma+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dplasma%2Benergy"><span id="translatedtitle">Estimates of magnetic flux, and energy balance in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> during substorm expansion</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hesse, Michael; Birn, Joachim; Pulkkinen, Tuija</p> <p>1996-01-01</p> <p>The energy and magnetic flux budgets of the magnetotail <span class="hlt">plasma</span> <span class="hlt">sheet</span> during substorm expansion are investigated. The possible mechanisms that change the energy content of the closed field line region which contains all the major dissipation mechanisms of relevance during substorms, are considered. The compression of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> mechanism and the diffusion mechanism are considered and excluded. It is concluded that the magnetic reconnection mechanism can accomplish the required transport. Data-based empirical magnetic field models are used to investigate the magnetic flux transport required to account for the observed magnetic field dipolarizations in the inner magnetosphere. It is found that the magnetic flux permeating the current <span class="hlt">sheet</span> is typically insufficient to supply the required magnetic flux. It is concluded that no major substorm-type magnetospheric reconfiguration is possible in the absence of magnetic reconnection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970026617','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970026617"><span id="translatedtitle">Penetration of the Interplanetary Magnetic Field B(sub y) into Earth's <span class="hlt">Plasma</span> <span class="hlt">Sheet</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hau, L.-N.; Erickson, G. M.</p> <p>1995-01-01</p> <p>There has been considerable recent interest in the relationship between the cross-tail magnetic field component B(sub y) and tail dynamics. The purpose of this paper is to give an overall description of the penetration of the interplanetary magnetic field (IMF) B(sub y) into the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span>. We show that <span class="hlt">plasma</span> <span class="hlt">sheet</span> B(sub y) may be generated by the differential shear motion of field lines and enhanced by flux tube compression. The latter mechanism leads to a B(sub y) analogue of the pressure-balance inconsistency as flux tubes move from the far tail toward the Earth. The growth of B(sub y), however, may be limited by the dawn-dusk asymmetry in the shear velocity as a result of <span class="hlt">plasma</span> <span class="hlt">sheet</span> tilting. B(sub y) penetration into the <span class="hlt">plasma</span> <span class="hlt">sheet</span> implies field-aligned currents flowing between hemispheres. These currents together with the IMF B(sub y) related mantle field-aligned currents effectively shield the lobe from the IMF B(sub y).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999APS..DPP.LI101Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999APS..DPP.LI101Y"><span id="translatedtitle">Investigation of the Neutral <span class="hlt">Sheet</span> Profile during Magnetic Reconnection in a Laboratory <span class="hlt">Plasma</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yamada, Masaaki</p> <p>1999-11-01</p> <p>Recent detailed data from laboratory <span class="hlt">plasma</span> experiments, satellite observations, theoretical analyses, and computer simulations have contributed significantly to the understanding of magnetic reconnection both in space and laboratory <span class="hlt">plasmas</span>. As magnetic field lines break and reconnect around the neutral region, a neutral <span class="hlt">sheet</span> current is generated. This current then heats the <span class="hlt">plasma</span>, and the opposing magnetic fields form a stationary equilibrium with the <span class="hlt">plasma</span> thermal pressure. This region is a focal point of reconnection since it requires proper treatment of local non-MHD effects in a <span class="hlt">plasma</span> which is highly conductive globally (with large Lundquist number S). Particularly, the profile of the neutral <span class="hlt">sheet</span> current is a very good indicator of the nature of reconnection. In this talk, we focus on the diverse and very intriguing features of the neutral <span class="hlt">sheet</span> in driven magnetic reconnection experiments on MRX(M. Yamada et al., Phys. Rev. Lett. 78), 3117 (1997); M. Yamada et al., Phys. <span class="hlt">Plasmas</span> 4, 1936 (1997)., which was built to investigate the fundamental physics of magnetic reconnection. The MHD approximation (S >> 1, ρi << L, v_A<< c) is satisfied globally in MRX <span class="hlt">plasmas</span>. In recent MRX experiments, the magnetic field profile of the neutral <span class="hlt">sheet</span> was measured precisely by magnetic probes with a spatial resolution of 0.25-0.5ρ_i, and B(x) data fit excellently to the Harris profile(E. G. Harris, Il Nuovo Cimento 23), 115 (1962); S. M. Mahajan, Phys. Fluids B 1, 43 (1989). B(x) ~ tanh[(x-x_0)/δ], indicating the formation of a stable, axisymmetric neutral <span class="hlt">sheet</span>. The <span class="hlt">sheet</span> thickness δ is found to be equal to the ion skin depth c/ω_pi, which is in very good agreement with recent numerical simulations(J. F. Drake et al., Geophys. Res. Lett. 24), 2921 (1997); D. Biskamp et al., Phys. Rev. Lett. 75, 3850 (1995); R. Horiuchi and T. Sato, Phys. <span class="hlt">Plasmas</span> 4, 277 (1997).. These data are also consistent with space observations both in the geotail region and the magnetopause. The detailed study of various additional local features of the reconnection region will be presented, along with further study of a generalized Sweet-Parker model(H. Ji et al., Phys. Rev. Lett. 80), 3256 (1998); H. Ji et al., Phys. <span class="hlt">Plasmas</span> 6, 1743 (1999)., measurements of enhanced resistivity, and studies of ion acceleration and heating. The relationship of MRX data to recent space observations and numerical simulations also will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009JGRA..114.9211T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009JGRA..114.9211T"><span id="translatedtitle">THEMIS observations of the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> during a substorm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tang, C. L.; Li, Z. Y.; Angelopoulos, V.; Mende, S. B.; Glassmeier, K. H.; Donovan, E.; Russell, C. T.; Lu, L.</p> <p>2009-09-01</p> <p>We present observations of a substorm on 13 March 2008 by Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft in the near-Earth tail during the <span class="hlt">plasma</span> <span class="hlt">sheet</span> expansion evidenced by increase in the <span class="hlt">plasma</span> density and temperature. The main features of the event are as follows: (1) Cross-tail current reduction or current disruption (CD) was observed in the near-Earth tail at X -8.0 RE and Y 2.0 RE, marked by a sharp drop of ?Bx? and accompanied by sharp increases in the <span class="hlt">plasma</span> density and temperature, manifesting a rapid expansion (recovery) of the local <span class="hlt">plasma</span> <span class="hlt">sheet</span>. During the course of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> expansion, the propagation speed of the dipolarization is 48 km/s in tailward direction and 35 km/s in azimuthal direction. (2) In the inner edge of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, slow flux pileup is observed. The magnetic flux pileup is characterized by continuous enhancement of Bz and Bt and a reduction of the <span class="hlt">plasma</span> density, pressure Pth, and ? in the flow-braking region. The tailward moving <span class="hlt">plasma</span> <span class="hlt">sheet</span> expansion (CD) is also passing across the flow-braking region. In short, the dipolarization in the inner edge of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> can be attributed to CD, while the tailward progression of dipolarization in the flow-braking region can be attributed to magnetic flux pileup. (3) A sharp decrease in the magnitude of Bx at P1 (-13.1 RE, 2.5 RE, -0.56 RE) prior to the dipolarization at P5 is difficult to explain as part of the outward evolution of the CD. The rapid change in the magnetic field topology, and signatures of earthward flows and dipolarization observed at P1 prior to Pi2 onset may be caused by inward motion of flux from magnetic reconnection in the midtail (20-30 RE). Tail reconnection prior to substorm expansion can result in a sudden change of the near-Earth configuration, which may result in instabilities related to the onset of CD.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhLA..380.1294B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhLA..380.1294B"><span id="translatedtitle">Magnetized relativistic <span class="hlt">electron</span>-ion <span class="hlt">plasma</span> expansion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Benkhelifa, El-Amine; Djebli, Mourad</p> <p>2016-03-01</p> <p>The dynamics of relativistic laser-produced <span class="hlt">plasma</span> expansion across a transverse magnetic field is investigated. Based on a one dimensional two-fluid model that includes pressure, enthalpy, and rest mass energy, the expansion is studied in the limit of λD (Debye length) ≤RL (Larmor radius) for magnetized <span class="hlt">electrons</span> and ions. Numerical investigation conducted for a quasi-neutral <span class="hlt">plasma</span> showed that the σ parameter describing the initial <span class="hlt">plasma</span> magnetization, and the <span class="hlt">plasma</span> β parameter, which is the ratio of kinetic to magnetic pressure are the key parameters governing the expansion dynamics. For σ ≪ 1, ion's front shows oscillations associated to the break-down of quasi-neutrality. This is due to the strong constraining effect and confinement of the magnetic field, which acts as a retarding medium slowing the <span class="hlt">plasma</span> expansion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DMP.D1026W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DMP.D1026W"><span id="translatedtitle"><span class="hlt">Electron</span> Forced Evaporative Cooling in Ultracold <span class="hlt">Plasmas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Witte, Craig; Roberts, Jacob</p> <p>2015-05-01</p> <p>Ultracold <span class="hlt">plasmas</span> (UCPs) are formed by photoionizing a collection of laser cooled atoms. Once formed, these <span class="hlt">plasmas</span> expand, cooling over the course of their expansion. In theory, further cooling should be obtainable by forcibly inducing <span class="hlt">electron</span> evaporation through applying DC electric fields to extract <span class="hlt">electrons</span>. However, for many UCP parameters, UCP <span class="hlt">electrons</span> are not fully thermalized until very late in the expansion. This creates complications in analyzing the UCP. This problem can be remedied by creating the ultracold <span class="hlt">plasma</span> at substantially lower initial temperatures since thermalization rates increase with decreasing temperature. Unfortunately, traditional models of UCP dynamics tend to break down in cases of substantial non-neutrality when used in the limit of zero temperature. We have developed a theoretical model that calculates potential depth and expansion dynamics of non-neutral UCPs in the limit of zero temperature. Such a model will allow us to quantify the degree of cooling obtained by evaporation as measured experimentally. Supported by the AFOSR.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6399325','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6399325"><span id="translatedtitle">Characterization of <span class="hlt">electron</span> cyclotron resonance hydrogen <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Outten, C.A. . Dept. of Nuclear Engineering); Barbour, J.C.; Wampler, W.R. )</p> <p>1990-01-01</p> <p><span class="hlt">Electron</span> cyclotron resonance (ECR) <span class="hlt">plasmas</span> yield low energy and high ion density <span class="hlt">plasmas</span>. The characteristics downstream of an ECR hydrogen <span class="hlt">plasma</span> were investigated as a function of microwave power and magnetic field. A fast-injection Langmuir probe and a carbon resistance probe were used to determine <span class="hlt">plasma</span> potential (V{sub p}), <span class="hlt">electron</span> density (N{sub e}), <span class="hlt">electron</span> temperature (T{sub e}), ion energy (T{sub i}), and ion fluence. Langmuir probe results showed that at 17 cm downstream from the ECR chamber the <span class="hlt">plasma</span> characteristics are approximately constant across the center 7 cm of the <span class="hlt">plasma</span> for 50 Watts of absorbed power. These results gave V{sub p} = 30 {plus minus} 5 eV, N{sub e} = 1 {times} 10{sup 8} cm{sup {minus}3}, and T{sub e} = 10--13 eV. In good agreement with the Langmuir probe results, carbon resistance probes have shown that T{sub i} {le} 50 eV. Also, based on hydrogen chemical sputtering of carbon, the hydrogen (ion and energetic neutrals) fluence rate was determined to be 1 {times} 10{sup 16}/cm{sup 2}-sec. at a pressure of 1 {times} 10{sup {minus}4} Torr and for 50 Watts of absorbed power. 19 refs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19880031406&hterms=magnet+generator&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmagnet%2Bgenerator','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19880031406&hterms=magnet+generator&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmagnet%2Bgenerator"><span id="translatedtitle">30-cm <span class="hlt">electron</span> cyclotron <span class="hlt">plasma</span> generator</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goede, Hank</p> <p>1987-01-01</p> <p>Experimental results on the development of a 30-cm-diam <span class="hlt">electron</span> cyclotron resonance <span class="hlt">plasma</span> generator are presented. This <span class="hlt">plasma</span> source utilizes samarium-cobalt magnets and microwave power at a frequency of 4.9 GHz to produce a uniform <span class="hlt">plasma</span> with densities of up to 3 x 10 to the 11th/cu cm in a continuous fashion. The <span class="hlt">plasma</span> generator contains no internal structures, and is thus inherently simple in construction and operation and inherently durable. The generator was operated with two different magnetic geometries. One used the rare-earth magnets arranged in an axial line cusp configuration, which directly showed <span class="hlt">plasma</span> production taking place near the walls of the generator where the <span class="hlt">electron</span> temperature was highest but with the <span class="hlt">plasma</span> density peaking in the central low B-field regions. The second configuration had magnets arranged to form azimuthal line cusps with approximately closed <span class="hlt">electron</span> drift surfaces; this configuration showed an improved electrical efficiency of about 135 eV/ion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21386823','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21386823"><span id="translatedtitle">Collisionless <span class="hlt">Plasma</span> Shocks in Striated <span class="hlt">Electron</span> Temperatures</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Guio, P.; Pecseli, H. L.</p> <p>2010-02-26</p> <p>The existence of low frequency waveguide modes of ion acoustic waves is demonstrated in magnetized <span class="hlt">plasmas</span> for <span class="hlt">electron</span> temperatures striated along the magnetic field lines. At higher frequencies, in a band between the ion cyclotron and the ion <span class="hlt">plasma</span> frequency, radiative modes develop and propagate obliquely to the field away from the striation. Arguments for the subsequent formation and propagation of electrostatic shock are presented and demonstrated numerically. For such <span class="hlt">plasma</span> conditions, the dissipation mechanism is the 'leakage' of the harmonics generated by the wave steepening.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPlPh..81b3001N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPlPh..81b3001N"><span id="translatedtitle">Ion and <span class="hlt">electron</span> heating during magnetic reconnection in weakly collisional <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Numata, Ryusuke; Loureiro, N. F.</p> <p>2015-04-01</p> <p>Magnetic reconnection and associated heating of ions and <span class="hlt">electrons</span> in strongly magnetized, weakly collisional <span class="hlt">plasmas</span> are studied by means of gyrokinetic simulations. It is shown that an appreciable amount of the released magnetic energy is dissipated to yield (irreversible) <span class="hlt">electron</span> and ion heating via phase mixing. <span class="hlt">Electron</span> heating is mostly localized to the magnetic island, not the current <span class="hlt">sheet</span>, and occurs after the dynamical reconnection stage. Ion heating is comparable to <span class="hlt">electron</span> heating only in high-? <span class="hlt">plasmas</span>, and results from both parallel and perpendicular phase mixing due to finite Larmor radius (FLR) effects; in space, ion heating is mostly localized to the interior of a secondary island (plasmoid) that arises from the instability of the current <span class="hlt">sheet</span>.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013NaPho...7..932.','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013NaPho...7..932."><span id="translatedtitle">Tamm states in <span class="hlt">electron</span> <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p></p> <p>2013-11-01</p> <p>Researchers have fabricated a voltage-tunable plasmonic crystal in a two-dimensional <span class="hlt">electron</span> gas that operates at terahertz frequencies. Nature Photonics spoke to Eric Shaner, Greg Dyer and Greg Aizin about the observation of Tamm states at the crystal's edge.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014Ap%26SS.349....5E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014Ap%26SS.349....5E"><span id="translatedtitle">Magnetosonic rogons in <span class="hlt">electron</span>-ion <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>El-Awady, E. I.; Rizvi, H.; Moslem, W. M.; El-Labany, S. K.; Raouf, A.; Djebli, M.</p> <p>2014-01-01</p> <p>Magnetosonic rogue waves (rogons) are investigated in an <span class="hlt">electron</span>-ion <span class="hlt">plasma</span> by deriving the nonlinear Schrdinger (NLS) equation for low frequency limit. The first- and second-order rogue wave solutions of the NLS equation are obtained analytically and examined numerically. It is found that for dense <span class="hlt">plasma</span> and stronger magnetic field the nonlinearity decreases, which causes the rogon amplitude becomes shorter. However, the <span class="hlt">electron</span> temperature pumping more energy to the background waves which are sucked to create rogue waves with taller amplitudes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19840030084&hterms=Plasma+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DPlasma%2Benergy','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19840030084&hterms=Plasma+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DPlasma%2Benergy"><span id="translatedtitle">Survey of low-energy <span class="hlt">plasma</span> <span class="hlt">electrons</span> in Saturn's magnetosphere - Voyagers 1 and 2</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sittler, E. C., Jr.; Ogilvie, K. W.; Scudder, J. D.</p> <p>1983-01-01</p> <p>The low energy <span class="hlt">plasma</span> <span class="hlt">electron</span> environment within Saturn's magnetosphere was surveyed by the <span class="hlt">Plasma</span> Science Experiment (PLS) during the Voyager encounters with Saturn. Over the full energy range of the PLS instrument (10 eV to 6 keV) the <span class="hlt">electron</span> distribution functions are clearly non-Maxwellian in character; they are composed of a cold (thermal) component with Maxwellian shape and a hot (suprathermal) non-Maxwellian component. A large scale positive radial gradient in <span class="hlt">electron</span> temperature is observed, increasing from less than 1 eV in the inner magnetosphere to as high as 800 eV in the outer magnetosphere. Three fundamentally different <span class="hlt">plasma</span> regimes were identified from the measurements: (1) the hot outer magnetosphere, (2) the extended <span class="hlt">plasma</span> <span class="hlt">sheet</span>, and (3) the inner <span class="hlt">plasma</span> torus. Previously announced in STAR as N83-34872</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830026601','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830026601"><span id="translatedtitle">Survey of low energy <span class="hlt">plasma</span> <span class="hlt">electrons</span> in Saturn's magnetosphere: Voyagers 1 and 2</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sittler, E. C., Jr.; Ogilvie, K. W.; Scudder, J. D.</p> <p>1983-01-01</p> <p>The low energy <span class="hlt">plasma</span> <span class="hlt">electron</span> environment within Saturn's magnetosphere was surveyed by the <span class="hlt">Plasma</span> Science Experiment (PLS) during the Voyager encounters with Saturn. Over the full energy range of the PLS instrument (10 eV to 6 keV) the <span class="hlt">electron</span> distribution functions are clearly non-Maxwellian in character; they are composed of a cold (thermal) component with Maxwellian shape and a hot (suprathermal) non-Maxwellian component. A large scale positive radial gradient in <span class="hlt">electron</span> temperature is observed, increasing from less than 1 eV in the inner magnetosphere to as high as 800 eV in the outer magnetosphere. Three fundamentally different <span class="hlt">plasma</span> regimes were identified from the measurements: (1) the hot outer magnetosphere, (2) the extended <span class="hlt">plasma</span> <span class="hlt">sheet</span>, and (3) the inner <span class="hlt">plasma</span> torus.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22269257','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22269257"><span id="translatedtitle"><span class="hlt">Electronic</span> and magnetic properties of Fe and Mn doped two dimensional hexagonal germanium <span class="hlt">sheets</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Soni, Himadri R. Jha, Prafulla K.</p> <p>2014-04-24</p> <p>Using first principles density functional theory calculations, the present paper reports systematic total energy calculations of the <span class="hlt">electronic</span> properties such as density of states and magnetic moment of pristine and iron and manganese doped two dimensional hexagonal germanium <span class="hlt">sheets</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM12B..06R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM12B..06R"><span id="translatedtitle">Multifluid MHD simulation of Saturn's magnetosphere: Dynamics of mass- and momentum-loading, and seasonal variation of the <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rajendar, A.; Paty, C. S.; Arridge, C. S.; Jackman, C. M.; Smith, H. T.</p> <p>2013-12-01</p> <p>Saturn's magnetosphere is driven externally, by the solar wind, and internally, by the planet's strong magnetic field, rapid rotation rate, and the addition of new <span class="hlt">plasma</span> created from Saturn's neutral cloud. Externally, the alignment of the rotational and magnetic dipole axes, combined with Saturn's substantial inclination to its plane of orbit result in substantial curvature of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> during solstice. Internally, new water group ions are produced in the inner regions of the magnetosphere from photoionization and <span class="hlt">electron</span>-impact ionization of the water vapor and OH cloud sourced from Enceladus and other icy bodies in Saturn's planetary system. In addition to this, charge-exchange collisions between the relatively fast-moving water group ions and the slower neutrals results in a net loss of momentum from the <span class="hlt">plasma</span>. In order to study these phenomena, we have made significant modifications to the Saturn multifluid model. This model has been previously used to investigate the external triggering of plasmoids and the interchange process using a fixed internal source rate. In order to improve the fidelity of the model, we have incorporated a physical source of mass- and momentum-loading by including an empirical representation of Saturn's neutral cloud and modifying the multifluid MHD equations to include mass- and momentum-loading terms. Collision cross-sections between ions, <span class="hlt">electrons</span>, and neutrals are calculated as functions of closure velocity and energy at each grid point and time step, enabling us to simulate the spatially and temporally varying <span class="hlt">plasma</span>-neutral interactions. In addition to this, by altering the angle of incidence of the solar wind relative to Saturn's rotational axis and applying a realistic latitudinally- and seasonally-varying ionospheric conductivity, we are also able to study seasonal effects on Saturn's magnetosphere. We use the updated multifluid simulation to investigate the dynamics of Saturn's magnetosphere, focusing specifically on the production of new <span class="hlt">plasma</span>, the resulting radial outflow, and corotation lag profiles. The simulation has produced well-defined interchange fingers, regions of cold inner-magnetosphere <span class="hlt">plasma</span> that lag corotation and move radially outwards, which are balanced by the inward flow of hot tenuous <span class="hlt">plasma</span> from the outer magnetosphere. We quantify the rate of interchange finger production, and from these calculate the net outward rate of <span class="hlt">plasma</span> flow. We then compare simulation output with observational data from the Cassini spacecraft to validate the new physics that we have incorporated. In addition to internal mass production and corotation, we also investigate external driver effects, in particular the seasonal variation of curvature of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840004981','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840004981"><span id="translatedtitle">The structure of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>-lobe boundary in the Earth's magnetotail</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Orsini, S.; Candidi, M.; Formisano, V.; Balsiger, H.; Ghielmetti, A.; Ogilvie, K. W.</p> <p>1982-01-01</p> <p>The structure of the magnetotail <span class="hlt">plasma</span> <span class="hlt">sheet-plasma</span> lobe boundary was studied by observing the properties of tailward flowing O+ ion beams, detected by the ISEE 2 <span class="hlt">plasma</span> experiment inside the boundary during three time periods. The computed value of the north-south electric field component as well as the O+ parameters are shown to change at the boundary. The results are related to other observations made in this region. The O+ parameters and the Ez component behavior are shown to be consistent with that expected from the topology of the electric field lines in the tail as mapped from the ionosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PhPl...15a3102B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PhPl...15a3102B"><span id="translatedtitle"><span class="hlt">Plasma</span>-loaded free-<span class="hlt">electron</span> laser with thermal <span class="hlt">electron</span> beam and background <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Babaei, S.; Maraghechi, B.</p> <p>2008-01-01</p> <p>Thermal properties of a <span class="hlt">plasma</span>-loaded free-<span class="hlt">electron</span> laser are studied with the aid of a dispersion relation obtained from the kinetic theory. The <span class="hlt">electron</span> beam and the background <span class="hlt">plasma</span> are assumed to have, respectively, small and finite momentum spread in the axial direction, using water-bag distribution functions. Thermal effects of the beam <span class="hlt">electrons</span> are found to be stronger than those of the <span class="hlt">plasma</span>. The maximum growth rate rises and falls as the momentum spread of the <span class="hlt">plasma</span> is increased over a wide interval. In the Compton regime, with the high-energy and low-density <span class="hlt">electron</span> beam, the <span class="hlt">plasma</span> and its momentum spread have almost no effects on the growth rate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4451805','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4451805"><span id="translatedtitle">Theoretical predictions on the <span class="hlt">electronic</span> structure and charge carrier mobility in 2D Phosphorus <span class="hlt">sheets</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Xiao, Jin; Long, Mengqiu; Zhang, Xiaojiao; Ouyang, Jun; Xu, Hui; Gao, Yongli</p> <p>2015-01-01</p> <p>We have investigated the <span class="hlt">electronic</span> structure and carrier mobility of four types of phosphorous monolayer <span class="hlt">sheet</span> (?-P, ?-P,?-P and ?-P) using density functional theory combined with Boltzmann transport method and relaxation time approximation. It is shown that ?-P, ?-P and ?-P are indirect gap semiconductors, while ?-P is a direct one. All four <span class="hlt">sheets</span> have ultrahigh carrier mobility and show anisotropy in-plane. The highest mobility value is ~3??105?cm2V?1s?1, which is comparable to that of graphene. Because of the huge difference between the hole and <span class="hlt">electron</span> mobilities, ?-P, ?-P and ?-P <span class="hlt">sheets</span> can be considered as n-type semiconductors, and ?-P <span class="hlt">sheet</span> can be considered as a p-type semiconductor. Our results suggest that phosphorous monolayer <span class="hlt">sheets</span> can be considered as a new type of two dimensional materials for applications in optoelectronics and nanoelectronic devices. PMID:26035176</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26035176','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26035176"><span id="translatedtitle">Theoretical predictions on the <span class="hlt">electronic</span> structure and charge carrier mobility in 2D phosphorus <span class="hlt">sheets</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xiao, Jin; Long, Mengqiu; Zhang, Xiaojiao; Ouyang, Jun; Xu, Hui; Gao, Yongli</p> <p>2015-01-01</p> <p>We have investigated the <span class="hlt">electronic</span> structure and carrier mobility of four types of phosphorous monolayer <span class="hlt">sheet</span> (?-P, ?-P,?-P and ?-P) using density functional theory combined with Boltzmann transport method and relaxation time approximation. It is shown that ?-P, ?-P and ?-P are indirect gap semiconductors, while ?-P is a direct one. All four <span class="hlt">sheets</span> have ultrahigh carrier mobility and show anisotropy in-plane. The highest mobility value is ~3 10(5) cm(2)V(-1)s(-1), which is comparable to that of graphene. Because of the huge difference between the hole and <span class="hlt">electron</span> mobilities, ?-P, ?-P and ?-P <span class="hlt">sheets</span> can be considered as n-type semiconductors, and ?-P <span class="hlt">sheet</span> can be considered as a p-type semiconductor. Our results suggest that phosphorous monolayer <span class="hlt">sheets</span> can be considered as a new type of two dimensional materials for applications in optoelectronics and nanoelectronic devices. PMID:26035176</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3174452','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3174452"><span id="translatedtitle">Kink-like mode of a double gradient instability in a compressible <span class="hlt">plasma</span> current <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Korovinskiy, D.B.; Ivanova, V.V.; Erkaev, N.V.; Semenov, V.S.; Ivanov, I.B.; Biernat, H.K.; Zellinger, M.</p> <p>2011-01-01</p> <p>A linear MHD instability of the electric current <span class="hlt">sheet</span>, characterized by a small normal magnetic field component, varying along the <span class="hlt">sheet</span>, is investigated. The tangential magnetic field component is modeled by a hyperbolic function, describing Harris-like variations of the field across the <span class="hlt">sheet</span>. For this problem, which is formulated in a 3D domain, the conventional compressible ideal MHD equations are applied. By assuming Fourier harmonics along the electric current, the linearized 3D equations are reduced to 2D ones. A finite difference numerical scheme is applied to examine the time evolution of small initial perturbations of the <span class="hlt">plasma</span> parameters. This work is an extended numerical study of the so called double gradient instability, a possible candidate for the explanation of flapping oscillations in the magnetotail current <span class="hlt">sheet</span>, which has been analyzed previously in the framework of a simplified analytical approach for an incompressible <span class="hlt">plasma</span>. The dispersion curve is obtained for the kink-like mode of the instability. It is shown that this curve demonstrates a quantitative agreement with the previous analytical result. The development of the instability is investigated also for various enhanced values of the normal magnetic field component. It is found that the characteristic values of the growth rate of the instability shows a linear dependence on the square root of the parameter, which scales uniformly the normal component of the magnetic field in the current <span class="hlt">sheet</span>. PMID:22053125</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..DPPNO5002H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..DPPNO5002H"><span id="translatedtitle">The Self-Consistent Generation of Current <span class="hlt">Sheets</span> in Astrophysical <span class="hlt">Plasma</span> Turbulence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Howes, Gregory</p> <p>2014-10-01</p> <p>In space and astrophysical <span class="hlt">plasma</span> turbulence, it has long been recognized that dissipation occurs predominantly in intermittent current <span class="hlt">sheets</span>, with vigorous activity in the past few years focused on obtaining observational evidence for such localized dissipation in the near-Earth solar wind. The nature of these magnetic discontinuities and their associated current <span class="hlt">sheets</span> measured in the solar wind remains unclear--are these discontinuities due to filamentary magnetic structure in the solar wind, or do they arise dynamically from turbulent interactions? Recent analytical solution, numerical validation, and experimental verification of the nonlinear energy transfer in Alfven wave collisions, the nonlinear interactions between counterpropagating Alfven waves, has established this interaction as the fundamental building block of astrophysical <span class="hlt">plasma</span> turbulence. Here I will present first-principles analytical calculations and supporting numerical simulations that Alfven wave collisions in the strong turbulence limit naturally produce current <span class="hlt">sheets</span>, providing the first theoretical unification of models of <span class="hlt">plasma</span> turbulence mediated by Alfven waves with ideas on localized dissipation in current <span class="hlt">sheets</span>. Supported by NSF CAREER Award AGS-1054061, NSF Grant PHY-10033446, and NASA Grant NNX10AC91G.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900043484&hterms=mass+diffusion&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dmass%2Bdiffusion','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900043484&hterms=mass+diffusion&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dmass%2Bdiffusion"><span id="translatedtitle">Ion precipitation from the inner <span class="hlt">plasma</span> <span class="hlt">sheet</span> due to stochastic diffusion</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zelenyi, L.; Galeev, A.; Kennel, C. F.</p> <p>1990-01-01</p> <p><span class="hlt">Plasma</span> <span class="hlt">sheet</span> ions do not conserve their first adiabatic invariant when the magnetic field is appreciably tail-like. They do conserve a different adiabatic invariant but only to linear, rather than exponential, accuracy in the appropriate small parameter. Thus significant stochastic diffusion can occur for particles crossing the separatrix dividing the segments of orbits on which the particles cross and do not cross the tail midplane. Such ions can escape the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and precipitate into the atmosphere. Stochastic scattering is strongest from those field lines where the ion's Larmor period in the normal component of the neutral <span class="hlt">sheet</span> magnetic field approximately equals its bounce period. By comparing the rates of stochastic ion loss and convection in the tail, it is possible to estimate the location and thickness of the inner edge of the ion <span class="hlt">plasma</span> <span class="hlt">sheet</span> created by stochastic ion loss. Ions of different masses precipitate into the atmosphere at slightly different locations. Since wave particle interactions are not needed, this precipitation will always occur and should be particularly evident during quiet geomagnetic conditions, when it is less likely to be masked by other precipitation mechanisms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910023729','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910023729"><span id="translatedtitle">High resolution measurements of density structures in the Jovian <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ansher, J. A.; Kurth, W. S.; Gurnett, D. A.; Goertz, C. K.</p> <p>1991-01-01</p> <p>A recent effort to digitize the <span class="hlt">plasma</span> density by using the low frequency cutoff of trapped continuum radiation in the vicinity of the Jovian <span class="hlt">plasma</span> <span class="hlt">sheet</span> has revealed the existence of sharply defined density structures in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. These structures typically have a <span class="hlt">plasma</span> density which is relatively constant but of order 50 percent greater or less than in the surrounding <span class="hlt">plasma</span>. At the boundaries of these structures, the transitions from low to high density occur on time scales of about ten seconds, which correspond to spatial dimensions on the order of a few ion Larmor radii. The structures themselves last for intervals from less than a minute to more than five minutes, corresponding to size scales from a fraction of a Jovian radius to more than a Jovian radius, depending of the velocity of the structure relative to the spacecraft. In view of the importance of near corotation <span class="hlt">plasma</span> flows, these structures are likely to be limited in both the longitudinal and radial dimensions and, therefore, could represent flux tubes with greatly varying <span class="hlt">plasma</span> content. These observations are presented as among the first to directly address the theoretically proposed interchange instability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1989dtes.rept.....B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1989dtes.rept.....B"><span id="translatedtitle">Dynamic trapping of <span class="hlt">electrons</span> in space <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brenning, N.; Bohm, M.; Faelthammar, Carl-Gunne</p> <p>1989-12-01</p> <p>The neutralization of positive space charge is studied in a case where heavy positive ions are added to a limited region of length in a collisionfree magnetized <span class="hlt">plasma</span>. It is found that <span class="hlt">electrons</span> which become accelerated towards the positive space charge can only achieve a partial neutralization: they overshoot, and the positive region becomes surrounded by negative space charges which screen the electric field from the surroundings. The process is studied both analytically and by computer simulations with consistent results: large positive potentials can be built up with respect to the surrounding <span class="hlt">plasma</span>. In the process in growth, the potential maximum traps <span class="hlt">electrons</span> in transit so that quasineutrality is maintained. The potential is proportional to the ambient <span class="hlt">electron</span> temperature and the square of the <span class="hlt">plasma</span> density increase, but independent of both the ion injection rate and the length. The process explains several features of the Porcupine xenon beam injection experiment. It could also have importance for the electrodynamic coupling between <span class="hlt">plasmas</span> of different densities, e.g., the injection of neutral clouds in the ionosphere of species that becomes rapidly photoionized, or penetration of dense <span class="hlt">plasma</span> clouds from the solar wind into the magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870059364&hterms=Giotto&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DGiotto','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870059364&hterms=Giotto&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DGiotto"><span id="translatedtitle">The Giotto <span class="hlt">electron</span> <span class="hlt">plasma</span> experiment</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Reme, H.; Cotin, F.; Cros, A.; Medale, J. L.; Sauvaud, J. A.</p> <p>1987-01-01</p> <p>The RPA-Copernic experiment aboard Giotto is described. The experiment is designed to measure the three-dimensional distributions of <span class="hlt">electrons</span> between 10 eV and 30 keV (by the RPA-1 EESA spectrometer) and the composition and distribution, close to the comet, of thermal positive ions in the mass range 10-213 amu (by the RPA-2 PICCA electrostatic mass analyzer). Three microprocessors interface RPA-1 EESA with RPA-2 PICCA and with the spacecraft and perform extensive onboard data processing. The experiment was operated successfully aboard the spacecraft in September 1985 during the encounter of Giotto with the comet Halley. The results provided by the EESA-1 indicate that the solar wind interaction with the comet Halley forms a well-defined bow shock with features quite different from the features of the comet Giacobini-Zinner bow shock; the data also showed a presence of accelerated keV <span class="hlt">electrons</span> at the cometary bow shock, upstream and in the transition region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1982JQSRT..27..345M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1982JQSRT..27..345M"><span id="translatedtitle"><span class="hlt">Electronic</span> energy-levels in dense <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>More, R. M.</p> <p>1982-03-01</p> <p>Modern inertial-confinement fusion experiments subject matter to extreme physical conditions previously studied only in theoretical astrophysics. At very high <span class="hlt">plasma</span> density, atomic energy states are significantly altered by electric fields of neighboring ions and by free <span class="hlt">electrons</span>; the resulting phenomena of pressure ionization and continuum lowering may be analyzed with a sequence of models, each adding new subtleties to a complex picture. This paper develops a simple parameterization of pressure ionization, discusses limitations of the Debye-Huckel model for <span class="hlt">plasma</span> perturbations, and surveys an approximate description of X-ray spectra based on the WKB approximation. WKB theory leads to a simple derivation of the screened hydrogenic model for <span class="hlt">plasma</span> ionization and radiative properties. <span class="hlt">Electron</span> eigenvalues are obtained from the total ion energy in agreement with Koopman's theorem, and the representation of spectral terms is improved by a new set of screening coefficients.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhPl...21k2306A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhPl...21k2306A"><span id="translatedtitle">Nonquasineutral <span class="hlt">electron</span> vortices in nonuniform <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Angus, J. R.; Richardson, A. S.; Ottinger, P. F.; Swanekamp, S. B.; Schumer, J. W.</p> <p>2014-11-01</p> <p><span class="hlt">Electron</span> vortices are observed in the numerical simulation of current carrying <span class="hlt">plasmas</span> on fast time scales where the ion motion can be ignored. In <span class="hlt">plasmas</span> with nonuniform density n, vortices drift in the B ?n direction with a speed that is on the order of the Hall speed. This provides a mechanism for magnetic field penetration into a <span class="hlt">plasma</span>. Here, we consider strong vortices with rotation speeds V? close to the speed of light c where the vortex size ? is on the order of the magnetic Debye length ?B=|B |/4 ?e n and the vortex is thus nonquasineutral. Drifting vortices are typically studied using the <span class="hlt">electron</span> magnetohydrodynamic model (EMHD), which ignores the displacement current and assumes quasineutrality. However, these assumptions are not strictly valid for drifting vortices when ? ? ?B. In this paper, 2D <span class="hlt">electron</span> vortices in nonuniform <span class="hlt">plasmas</span> are studied for the first time using a fully electromagnetic, collisionless fluid code. Relatively large amplitude oscillations with periods that correspond to high frequency extraordinary modes are observed in the average drift speed. The drift speed W is calculated by averaging the <span class="hlt">electron</span> velocity field over the vorticity. Interestingly, the time-averaged W from these simulations matches very well with W from the much simpler EMHD simulations even for strong vortices with order unity charge density separation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22403262','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22403262"><span id="translatedtitle">Nonquasineutral <span class="hlt">electron</span> vortices in nonuniform <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Angus, J. R.; Richardson, A. S.; Swanekamp, S. B.; Schumer, J. W.; Ottinger, P. F.</p> <p>2014-11-15</p> <p><span class="hlt">Electron</span> vortices are observed in the numerical simulation of current carrying <span class="hlt">plasmas</span> on fast time scales where the ion motion can be ignored. In <span class="hlt">plasmas</span> with nonuniform density n, vortices drift in the B???n direction with a speed that is on the order of the Hall speed. This provides a mechanism for magnetic field penetration into a <span class="hlt">plasma</span>. Here, we consider strong vortices with rotation speeds V{sub ?} close to the speed of light c where the vortex size ? is on the order of the magnetic Debye length ?{sub B}=|B|/4?en and the vortex is thus nonquasineutral. Drifting vortices are typically studied using the <span class="hlt">electron</span> magnetohydrodynamic model (EMHD), which ignores the displacement current and assumes quasineutrality. However, these assumptions are not strictly valid for drifting vortices when ?????{sub B}. In this paper, 2D <span class="hlt">electron</span> vortices in nonuniform <span class="hlt">plasmas</span> are studied for the first time using a fully electromagnetic, collisionless fluid code. Relatively large amplitude oscillations with periods that correspond to high frequency extraordinary modes are observed in the average drift speed. The drift speed W is calculated by averaging the <span class="hlt">electron</span> velocity field over the vorticity. Interestingly, the time-averaged W from these simulations matches very well with W from the much simpler EMHD simulations even for strong vortices with order unity charge density separation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21612220','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21612220"><span id="translatedtitle"><span class="hlt">Electron</span> beam-<span class="hlt">plasma</span> interaction in a dusty <span class="hlt">plasma</span> with excess suprathermal <span class="hlt">electrons</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Danehkar, A.; Saini, N. S.; Hellberg, M. A.; Kourakis, I.</p> <p>2011-11-29</p> <p>The existence of large-amplitude <span class="hlt">electron</span>-acoustic solitary structures is investigated in an unmagnetized and collisionless two-temperature dusty <span class="hlt">plasma</span> penetrated by an <span class="hlt">electron</span> beam. A nonlinear pseudopotential technique is used to investigate the occurrence of stationary-profile solitary waves, and their parametric dependence on the <span class="hlt">electron</span> beam and dust perturbation is discussed.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMSM14B..03L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMSM14B..03L"><span id="translatedtitle">ELF wave intensification in conjunction with fast earthward flow in the mid-tail <span class="hlt">plasma</span> <span class="hlt">sheet</span> ------- A THEMIS survey</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liang, J.; Ni, B.; Cully, C. M.; Donovan, E. F.; Thorne, R. M.; Themis Team</p> <p>2010-12-01</p> <p>A number of recent studies have revealed a close association between the fast earthward flows and dipolarization fronts in the magnetotail and the <span class="hlt">plasma</span> wave intensifications in the ELF/VLF range, including the lower-hybrid waves, whistler-mode and <span class="hlt">electron</span> cyclotron waves. Those waves may play crucial roles in the acceleration and pitch-angle scattering of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> <span class="hlt">electrons</span>, and in turn produce a macroscopic effect accompanying the fast flows. In this study, we perform a statistical survey of the THEMIS B/C data over the 2008 and 2009 tail seasons, and select ~110 fast earthward flow intervals in which the probes were mostly located in the mid-tail central <span class="hlt">plasma</span> <span class="hlt">sheet</span> (CPS) region. We investigate the filterbank (FBK) dataset of the electric field instrument (EFI) and search coil magnetometer (SCM) during the collected fast flow intervals, and identify an unambiguous trend of increasing ELF wave intensities with the convective flow enhancement. Notwithstanding the relatively wide bandwidth of FBK data we may still distinguish the existence of the lower-hybrid waves, the whistler-mode waves, and the electrostatic waves at f>f_ce. On a further examining of the flow-associated whistler-mode waves we notice a mixture of the quasi-electrostatic and electromagnetic wave modes, implying a broad distribution of the wave normal angles. We tentatively suggest that the energetic <span class="hlt">electron</span> beam originated from the reconnection site and/or the local dipolarizatoin front might be the main driving mechanism of the flow-associated ELF wave intensifications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.7416Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.7416Y"><span id="translatedtitle">On the contribution of <span class="hlt">plasma</span> <span class="hlt">sheet</span> bubbles to the storm time ring current</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Jian; Toffoletto, Frank R.; Wolf, Richard A.; Sazykin, Stanislav</p> <p>2015-09-01</p> <p>Particle injections occur frequently inside 10 Re during geomagnetic storms. They are commonly associated with bursty bulk flows or <span class="hlt">plasma</span> <span class="hlt">sheet</span> bubbles transported from the tail to the inner magnetosphere. Although observations and theoretical arguments have suggested that they may have an important role in storm time dynamics, this assertion has not been addressed quantitatively. In this paper, we investigate which process is dominant for the storm time ring current buildup: large-scale enhanced convection or localized bubble injections. We use the Rice Convection Model-Equilibrium (RCM-E) to model a series of idealized storm main phases. The boundary conditions at 14-15 Re on the nightside are adjusted to randomly inject bubbles to a degree roughly consistent with observed statistical properties. A test particle tracing technique is then used to identify the source of the ring current <span class="hlt">plasma</span>. We find that the contribution of <span class="hlt">plasma</span> <span class="hlt">sheet</span> bubbles to the ring current energy increases from ~20% for weak storms to ~50% for moderate storms and levels off at ~61% for intense storms, while the contribution of trapped particles decreases from ~60% for weak storms to ~30% for moderate and ~21% for intense storms. The contribution of nonbubble <span class="hlt">plasma</span> <span class="hlt">sheet</span> flux tubes remains ~20% on average regardless of the storm intensity. Consistent with previous RCM and RCM-E simulations, our results show that the mechanisms for <span class="hlt">plasma</span> <span class="hlt">sheet</span> bubbles enhancing the ring current energy are (1) the deep penetration of bubbles and (2) the bulk <span class="hlt">plasma</span> pushed ahead of bubbles. Both the bubbles and the <span class="hlt">plasma</span> pushed ahead typically contain larger distribution functions than those in the inner magnetosphere at quiet times. An integrated effect of those individual bubble injections is the gradual enhancement of the storm time ring current. We also make two predictions testable against observations. First, fluctuations over a time scale of 5-20 min in the <span class="hlt">plasma</span> distributions and electric field can be seen in the central ring current region for the storm main phase. We find that the <span class="hlt">plasma</span> pressure and the electric field EY there vary over about 10%-30% and 50%-300% of the background values, respectively. Second, the maximum <span class="hlt">plasma</span> pressure and magnetic field depression in the central ring current region during the main phase are well correlated with the Dst index.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMSM53D..04S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMSM53D..04S"><span id="translatedtitle">Relationship Between Ground-based and In-situ <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> Measurements of Convection Penetration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sanchez, E. R.</p> <p>2009-12-01</p> <p>Shortly after the discovery of bursty <span class="hlt">plasma</span> <span class="hlt">sheet</span> convection, a number of observational studies have suggested a link between earthward flow bursts observed near the midnight central <span class="hlt">plasma</span> <span class="hlt">sheet</span> and auroral intensifications at the polar cap boundary (polar cap boundary intensifications or PBIs) and the southward propagating aurora (auroral streamers). Three different stages are identified during the southward progression of the streamers. In the first stage there is a boundary brightening followed, often within a few minutes, by the start of the propagation of aurora in the southward direction. The second stage, which usually lasts up to ten minutes, consists of the propagation of the auroral streamer into the equatorward edge of the aurora. In the third stage, the arrival of the streamer to the equatorward edge of the oval coincides with the onset of a bright spot that can last for as long as 20 minutes. Bursty convection is observed in association with streamers most commonly during steady magnetospheric convection and substorm recovery, although it is also observed in general during periods of sustained geomagnetic activity. This investigation has two objectives. The first is to determine whether reconnection is enhanced concurrently with the PBIs and whether the duration of the enhancement coincides with the southward expansion of the auroral streamers. The second objective is to determine whether the enhanced tail reconnection is associated with penetration of under-dense flux tubes into near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span>. Ground-based multi-spectral optical measurements and in-situ Geotail and THEMIS measurements in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> during extended periods of southward IMF show the causal chain whereby PBIs are indeed the optical manifestation of reconnection intensifications that power, in some cases, the penetration of fast convection into the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. Observations show, however, that there are also intense flow bursts (~ 1000 km/s) without any clear indication of streamers and streamers without a corresponding flow burst. We discuss the consequences of these apparent discrepancies on the paradigm of penetration of under-dense flux tubes in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ANSNN...6d5009N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ANSNN...6d5009N"><span id="translatedtitle">Theory of photon<span class="hlt">electron</span> interaction in single-layer graphene <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nguyen, Bich Ha; Hieu Nguyen, Van; Bui, Dinh Hoi; Thu Phuong Le, Thi</p> <p>2015-12-01</p> <p>The purpose of this work is to elaborate the quantum theory of photon<span class="hlt">electron</span> interaction in a single-layer graphene <span class="hlt">sheet</span>. Since the light source must be located outside the extremely thin graphene <span class="hlt">sheet</span>, the problem must be formulated and solved in the three-dimensional physical space, in which the graphene <span class="hlt">sheet</span> is a thin plane layer. It is convenient to use the orthogonal coordinate system in which the xOy coordinate plane is located in the middle of the plane graphene <span class="hlt">sheet</span> and therefore the Oz axis is perpendicular to this plane. For the simplicity we assume that the quantum motions of <span class="hlt">electron</span> in the directions parallel to the coordinate plane xOy and that along the direction of the Oz axis are independent. Then we have a relatively simple formula for the overall Hamiltonian of the <span class="hlt">electron</span> gas in the graphene <span class="hlt">sheet</span>. The explicit expressions of the wave functions of the charge carriers are easily derived. The <span class="hlt">electron</span>hole formalism is introduced, and the Hamiltonian of the interaction of some external quantum electromagnetic field with the charge carriers in the graphene <span class="hlt">sheet</span> is established. From the expression of this interaction Hamiltonian it is straightforward to derive the matrix elements of photons with the Dirac fermionDirac hole pairs as well as with the <span class="hlt">electrons</span> in the quantum well along the direction of the Oz axis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19720058741&hterms=effects+depression&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Deffects%2Bdepression','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19720058741&hterms=effects+depression&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Deffects%2Bdepression"><span id="translatedtitle">On the diamagnetic effect of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> near 60 earth radii.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Meng, C.-I.; Mihalov, J. D.</p> <p>1972-01-01</p> <p>The two-dimensional (YZ plane) spatial distribution of magnetic field magnitudes in the geomagnetic tail at the lunar distance is given in both the solar magnetospheric and the neutral-<span class="hlt">sheet</span> coordinate systems by using three years of data from the Ames magnetometer on Explorer 35. The effect of changes in geomagnetic activity is also presented. In the magnetotail near 60 earth radii, a broad region in which the magnetic field intensity is relatively weak in comparison with that in the other region of the tail is located adjacent to the solar magnetospheric equatorial plane and the calculated neutral <span class="hlt">sheet</span>. This depression of the field due to the diamagnetic effect of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> is more evident during times of minimum geomagnetic activity.-</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014Ap%26SS.353..163S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014Ap%26SS.353..163S"><span id="translatedtitle"><span class="hlt">Electron</span> acoustic blow up solitary waves and periodic waves in an unmagnetized <span class="hlt">plasma</span> with kappa distributed hot <span class="hlt">electrons</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saha, Asit; Chatterjee, Prasanta</p> <p>2014-09-01</p> <p><span class="hlt">Electron</span> acoustic blow up solitary waves and periodic waves are studied in a classical unmagnetized <span class="hlt">plasma</span> containing cold <span class="hlt">electron</span> fluid, kappa distributed hot <span class="hlt">electrons</span> and stationary ions. We obtain Korteweg-de Vries (KdV) equation for <span class="hlt">electron</span> acoustic waves (EAWs) using the reductive perturbation technique (RPT). Applying bifurcation theory of planar dynamical systems to the obtained KdV equation, we prove the existence of <span class="hlt">electron</span> acoustic blowup solitary and periodic wave solutions. Depending on different physical parameters, two types of exact explicit solutions of the mentioned waves are derived. Our model may be applied to explain blow up solitary and periodic wave features that may occur in the planetary magnetosphere and the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20080037619&hterms=Andrew+Park&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DAndrew%2BPark','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20080037619&hterms=Andrew+Park&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DAndrew%2BPark"><span id="translatedtitle">Using PEACE Data from the four CLUSTER Spacecraft to Measure Compressibility, Vorticity, and the Taylor Microscale in the Magnetosheath and <span class="hlt">Plasma</span> <span class="hlt">Sheet</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goldstein, Melvyn L.; Parks, George; Gurgiolo, C.; Fazakerley, Andrew N.</p> <p>2008-01-01</p> <p>We present determinations of compressibility and vorticity in the magnetosheath and <span class="hlt">plasma</span> <span class="hlt">sheet</span> using moments from the four PEACE thermal <span class="hlt">electron</span> instruments on CLUSTER. The methodology used assumes a linear variation of the moments throughout the volume defined by the four satellites, which allows spatially independent estimates of the divergence, curl, and gradient. Once the vorticity has been computed, it is possible to estimate directly the Taylor microscale. We have shown previously that the technique works well in the solar wind. Because the background flow speed in the magnetosheath and <span class="hlt">plasma</span> <span class="hlt">sheet</span> is usually less than the Alfven speed, the Taylor frozen-in-flow approximation cannot be used. Consequently, this four spacecraft approach is the only viable method for obtaining the wave number properties of the ambient fluctuations. Our results using <span class="hlt">electron</span> velocity moments will be compared with previous work using magnetometer data from the FGM experiment on Cluster.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/944293','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/944293"><span id="translatedtitle"><span class="hlt">Electron</span> Scattering in Hot/Warm <span class="hlt">Plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rozsnyai, B F</p> <p>2008-01-18</p> <p>Electrical and thermal conductivities are presented for aluminum, iron and copper <span class="hlt">plasmas</span> at various temperatures, and for gold between 15000 and 30000 Kelvin. The calculations are based on the continuum wave functions computed in the potential of the temperature and density dependent self-consistent 'average atom' (AA) model of the <span class="hlt">plasma</span>. The cross sections are calculated by using the phase shifts of the continuum <span class="hlt">electron</span> wave functions and also in the Born approximation. We show the combined effect of the thermal and radiative transport on the effective Rosseland mean opacities at temperatures from 1 to 1000 eV. Comparisons with low temperature experimental data are also presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AnGeo..33..845M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AnGeo..33..845M"><span id="translatedtitle">Solar-wind control of <span class="hlt">plasma</span> <span class="hlt">sheet</span> dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Myllys, M.; Kilpua, E.; Pulkkinen, T.</p> <p>2015-07-01</p> <p>The purpose of this study is to quantify how solar-wind conditions affect the energy and <span class="hlt">plasma</span> transport in the geomagnetic tail and its large-scale configuration. To identify the role of various effects, the magnetospheric data were sorted according to different solar-wind <span class="hlt">plasma</span> and interplanetary magnetic field (IMF) parameters: speed, dynamic pressure, IMF north-south component, epsilon parameter, Auroral Electrojet (AE) index and IMF ultra low-frequency (ULF) fluctuation power. We study variations in the average flow speed pattern and the occurrence rate of fast flow bursts in the magnetotail during different solar-wind conditions using magnetospheric data from five Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission spacecraft and solar-wind data from NASA's OMNIWeb. The time interval covers the years from 2008 to 2011 during the deep solar minimum between cycles 23 and 24 and the relatively quiet rising phase of cycle 24. Hence, we investigate magnetospheric processes and solar-wind-magnetospheric coupling during a relatively quiet state of the magnetosphere. We show that the occurrence rate of the fast (|Vtail| > 100 km s-1) sunward flows varies under different solar-wind conditions more than the occurrence of the fast tailward flows. The occurrence frequency of the fast tailward flows does not change much with the solar-wind conditions. We also note that the sign of the IMF BZ has the most visible effect on the occurrence rate and pattern of the fast sunward flows. High-speed flow bursts are more common during the slow than fast solar-wind conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150009523','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150009523"><span id="translatedtitle">Effect of <span class="hlt">Electron</span> Beam Irradiation on the Tensile Properties of Carbon Nanotubes <span class="hlt">Sheets</span> and Yarns</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Williams, Tiffany S.; Miller, Sandi G.; Baker, James S.; McCorkle, Linda S.; Meador, Michael A.</p> <p>2013-01-01</p> <p>Carbon nanotube <span class="hlt">sheets</span> and yarns were irradiated using <span class="hlt">electron</span> beam (e-beam) energy to determine the effect of irradiation dose on the tensile properties. Results showed that a slight change in tensile strength occurred after irradiating as-received CNT <span class="hlt">sheets</span> for 20 minutes, and a slight decrease in tensile strength as the irradiation time approached 90 minutes. On the other hand, the addition of small molecules to the CNT <span class="hlt">sheet</span> surface had a greater effect on the tensile properties of e-beam irradiated CNT <span class="hlt">sheets</span>. Some functionalized CNT <span class="hlt">sheets</span> displayed up to a 57% increase in tensile strength following 90 minutes of e-beam exposure. In addition, as-received CNT yarns showed a significant increase in tensile strength as the irradiation time increased.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5916052','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5916052"><span id="translatedtitle">Free <span class="hlt">electron</span> laser with small period wiggler and <span class="hlt">sheet</span> <span class="hlt">electron</span> beam: A study of the feasibility of operation at 300 GHz with 1 MW CW output power</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Booske, J.H.; Granatstein, V.L.; Antonsen, T.M. Jr.; Destler, W.W.; Finn, J.; Latham, P.E.; Levush, B.; Mayergoyz, I.D.; Radack, D.; Rodgers, J.</p> <p>1988-01-01</p> <p>The use of a small period wiggler (/ell//sub ..omega../ < 1 cm) together with a <span class="hlt">sheet</span> <span class="hlt">electron</span> beam has been proposed as a low cost source of power for <span class="hlt">electron</span> cyclotron resonance heating (ECRH) in magnetic fusion <span class="hlt">plasmas</span>. Other potential applications include space-based radar systems. We have experimentally demonstrated stable propagation of a <span class="hlt">sheet</span> beam (18 A. 1 mm /times/ 20 mm) through a ten-period wiggler electromagnet with peak field of 1.2 kG. Calculation of microwave wall heating and pressurized water cooling have also been carried out, and indicate the feasibility of operating a near-millimeter, <span class="hlt">sheet</span> beam FEL with an output power of 1 MW CW (corresponding to power density into the walls of 2 kW/cm/sup 2/). Based on these encouraging results, a proof-of-principle experiment is being assembled, and is aimed at demonstrating FEL operating at 120 GHz with 300 kW output power in 1 ..mu..s pulses: <span class="hlt">electron</span> energy would be 410 keV. Preliminary design of a 300 GHz 1 MW FEL with an untapered wiggler is also presented. 10 refs., 5 figs., 3 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1989NIMPA.285...92B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1989NIMPA.285...92B"><span id="translatedtitle">Free <span class="hlt">electron</span> laser with small period wiggler and <span class="hlt">sheet</span> <span class="hlt">electron</span> beam: A study of the feasibility of operation at 300 GHz with 1 MW cw output power</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Booske, J. H.; Granatstein, V. L.; Antonsen, T. M.; Destler, W. W.; Finn, J.; Latham, P. E.; Levush, B.; Mayergoyz, I. D.; Radack, D.; Rodgers, J.; Read, M. E.; Linz, A.</p> <p>1989-12-01</p> <p>The use of a small period wiggler ( lw < 1 cm) together with a <span class="hlt">sheet</span> <span class="hlt">electron</span> beam has been proposed as a low cost source of power for <span class="hlt">electron</span> cyclotron resonance heating (ECRH) in magnetic fusion <span class="hlt">plasmas</span>. Other potential applications include space-based radar systems. We have experimentally demonstrated stable propagation of a <span class="hlt">sheet</span> beam (18 A, 1 mm 20 mm) through a ten-period wiggler electromagnet with a peak field of 1.2 kG. Calculations of microwave wall heating and pressurized water cooling have also been carried out, and indicate the feasibility of operating a near-millimeter, <span class="hlt">sheet</span> beam FEL with an output power of 1 MW cw (corresponding to a power density into the walls of 2 kW/cm 2). Based on these encouraging results, a proof-of-principle experiment is being assembled, and is aimed at demonstrating a FEL operating at 120 GHz with 300 kW output power in 1 ?s pulses: the <span class="hlt">electron</span> energy would be 410 keV. A preliminary design of a 300 GHz, 1 MW FEL with an untapered wiggler is also presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19890059894&hterms=kinetic+alfven+waves&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dkinetic%2Balfven%2Bwaves','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19890059894&hterms=kinetic+alfven+waves&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dkinetic%2Balfven%2Bwaves"><span id="translatedtitle">Ion beam generation at the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer by kinetic Alfven waves</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Moghaddam-Taaheri, E.; Goertz, C. K.; Smith, R. A.</p> <p>1989-01-01</p> <p>A two-dimensional quasi-linear numerical code was developed for studying ion beam generation at the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer by kinetic Alfven waves. The model assumes that the central <span class="hlt">plasma</span> <span class="hlt">sheet</span> is the particle source, and that the last magnetic field lines on which kinetic Alfven waves exist and diffusion occurs can be either open or closed. As the possible source for the excitement of the kinetic Alfven waves responsible for ion diffusion, the resonant mode conversion of the surface waves to kinetic Alfven waves is considered. It is shown that, depending on the topology of the magnetic field at the lobe side of the simulation system, i.e., on whether field lines are open or closed, the ion distribution function may or may not reach a steady state.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFMSM11B0819S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFMSM11B0819S"><span id="translatedtitle">Quiet Time Association Between Repetitive Pi2s, PBIs, and <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> Particle Fluxes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sutcliffe, P. R.; Lyons, L. R.</p> <p>2001-12-01</p> <p>Trains of Pi2 pulsations have been observed at low latitudes during extremely quiet magnetospheric and solar wind conditions. Poleward boundary intensifications (PBIs), which have been inferred using ground magnetic field data, are observed simultaneously with a ~30 min repetition rate. There is also an excellent correlation with energetic particle enhancements at X=-15 Re in the tail <span class="hlt">plasma</span> <span class="hlt">sheet</span>. This association demonstrates the large-scale nature of the magnetosphere-ionosphere disturbance with gives rise to PBIs and shows that the disturbance may have important effects on energetic particles within the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. It also shows for the first time that PBIs are associated with clearly observable Pi2 pulsations at low latitudes. Our observations are also consistent with the possibility that PBIs are part of a large-scale magnetospheric oscillation with ~30 min period.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhPl...22l3109Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhPl...22l3109Z"><span id="translatedtitle">Laser-driven <span class="hlt">electron</span> acceleration in an inhomogeneous <span class="hlt">plasma</span> channel</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Rong; Cheng, Li-Hong; Xue, Ju-Kui</p> <p>2015-12-01</p> <p>We study the laser-driven <span class="hlt">electron</span> acceleration in a transversely inhomogeneous <span class="hlt">plasma</span> channel. We find that, in inhomogeneous <span class="hlt">plasma</span> channel, the developing of instability for <span class="hlt">electron</span> acceleration and the <span class="hlt">electron</span> energy gain can be controlled by adjusting the laser polarization angle and inhomogeneity of <span class="hlt">plasma</span> channel. That is, we can short the accelerating length and enhance the energy gain in inhomogeneous <span class="hlt">plasma</span> channel by adjusting the laser polarization angle and inhomogeneity of the <span class="hlt">plasma</span> channel.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21335788','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21335788"><span id="translatedtitle"><span class="hlt">Electron</span> Cyclotron Heating in RFP <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bilato, R.; Poli, E.; Volpe, F.; Koehn, A.; Cavazzana, R.; Paccagnella, R.; Farina, D.</p> <p>2009-11-26</p> <p>Reversed field pinches (RFP) <span class="hlt">plasmas</span> are typically overdense ({omega}{sub pe}>{omega}{sub ce}) and thus not suitable for conventional <span class="hlt">electron</span> cyclotron (EC) heating and current drive. In recent high <span class="hlt">plasma</span> current discharges (I{sub p}>1.5 MA), however, the RFX-mod device was operated in underdense conditions ({omega}{sub pe}<{omega}{sub ce}) for the first time in an RFP. Thus, it is now possible to envisage heating the RFP <span class="hlt">plasma</span> core by conventional EC at the 2nd harmonic, in the ordinary or extraordinary mode. We present a preliminary study of EC-heating feasibility in RFX-mod with the use of beam-tracing and full-wave codes. Although not competitive - as a heating system - with multi-MW Ohmic heating in an RFP, EC might be useful for perturbative transport studies, even at moderate power (hundreds of kW), and, more generally, for applications requiring localized power deposition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015TESS....120310M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015TESS....120310M"><span id="translatedtitle">Hinode/XRT Measurements of Turbulent Velocities in Flare <span class="hlt">Plasma</span> <span class="hlt">Sheets</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McKenzie, David; Freed, Michael</p> <p>2015-04-01</p> <p>The turbulent, dynamic motions that we observe in the hot <span class="hlt">plasma</span> surrounding current <span class="hlt">sheets</span> very likely distort the embedded magnetic fields, resulting in reduced length scales and locally augmented resistivities. These conditions may help to accelerate and/or prolong the reconnection in solar flares. Although we cannot as yet measure directly the magnetic fields in the corona, the velocity fields within the flare <span class="hlt">plasma</span> <span class="hlt">sheets</span> provide a means to study the conditions that control the spatial and temporal scales of reconnection, in the locations and at the times that are relevant to structuring the magnetic fields.The <span class="hlt">plasma</span> <span class="hlt">sheets</span> are observable in many flares in soft X-ray and EUV wavelengths, due to their high temperatures. For two recent flares observed with the Hinode X-Ray Telescope (XRT), we have analyzed the velocity fields with a local correlation tracking technique, and compared to measurements from the Solar Dynamics Observatory Atmospheric Imaging Assembly (SDO/AIA).This work is supported by NASA under contract NNM07AB07C with the Smithsonian Astrophysical Observatory, and by grant NNX14AD43G.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.4736P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.4736P"><span id="translatedtitle">Polytropic index of central <span class="hlt">plasma</span> <span class="hlt">sheet</span> ions based on MHD Bernoulli integral</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pang, Xuexia; Cao, Jinbin; Liu, Wenlong; Ma, Yuduan; Lu, Haoyu; Yang, Junying; Li, Liuyuan; Liu, Xu; Wang, Jing; Wang, Tieyan; Yu, Jiang</p> <p>2015-06-01</p> <p>This paper uses the data of Cluster from 2001 to 2009 to study the polytropic processes of central <span class="hlt">plasma</span> <span class="hlt">sheet</span> (CPS) ions. We first adopt the approach of MHD Bernoulli integral (MBI) to identify homogeneous streamflow tubes (quasi-invariant MBI regions) and then calculate the polytropic index of ions for those streamflow tubes whose outward electromagnetic energy ratios δ < 0.05. The central <span class="hlt">plasma</span> <span class="hlt">sheet</span> is actually a complicated system, which comprises many streamflow tubes with different polytropic relations and the transition layers in between. The polytropic indexes of the CPS ions range from 0.1 to 1.8 and have a quasi-Gaussian distribution. The median polytropic index is 0.93 for AE < 200 nT and 0.91 for AE ≥ 200 nT. Thus, there is no obvious difference between the polytropic indexes of the quiet time and the substorm time CPS ions, which suggests that the thinning and thickening processes of <span class="hlt">plasma</span> <span class="hlt">sheet</span> during substorm times do not change obviously the polytropic relation of the CPS ions. The statistical analysis using different δ (δ < 0.05, 0.025, and 0.01) shows that the outward emission of electromagnetic energy is an effective cooling mechanism and can make the polytropic index to decrease and shift toward isobaric. It is inferred that the CPS ions as a whole much likely behave in a way between isobaric and isothermal.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007ApJ...670..702Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007ApJ...670..702Z"><span id="translatedtitle">Particle Acceleration and Magnetic Dissipation in Relativistic Current <span class="hlt">Sheet</span> of Pair <span class="hlt">Plasmas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zenitani, S.; Hoshino, M.</p> <p>2007-11-01</p> <p>We study linear and nonlinear development of relativistic and ultrarelativistic current <span class="hlt">sheets</span> of pair (e+/-) <span class="hlt">plasmas</span> with antiparallel magnetic fields. Two types of two-dimensional problems are investigated by particle-in-cell simulations. First, we present the development of relativistic magnetic reconnection, whose outflow speed is on the order of the light speed c. It is demonstrated that particles are strongly accelerated in and around the reconnection region and that most of the magnetic energy is converted into a ``nonthermal'' part of <span class="hlt">plasma</span> kinetic energy. Second, we present another two-dimensional problem of a current <span class="hlt">sheet</span> in a cross field plane. In this case, the relativistic drift kink instability (RDKI) occurs. Particle acceleration also takes place, but the RDKI quickly dissipates the magnetic energy into <span class="hlt">plasma</span> heat. We discuss the mechanism of particle acceleration and the theory of the RDKI in detail. It is important that properties of these two processes are similar in the relativistic regime of T>~mc2, as long as we consider the kinetics. Comparison of the two processes indicates that magnetic dissipation by the RDKI is a more favorable process in the relativistic current <span class="hlt">sheet</span>. Therefore, the striped pulsar wind scenario should be reconsidered by the RDKI.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.3415K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.3415K"><span id="translatedtitle">Distribution of energetic oxygen and hydrogen in the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kronberg, E. A.; Grigorenko, E. E.; Haaland, S. E.; Daly, P. W.; Delcourt, D. C.; Luo, H.; Kistler, L. M.; Dandouras, I.</p> <p>2015-05-01</p> <p>The spatial distributions of different ion species are useful indicators for <span class="hlt">plasma</span> <span class="hlt">sheet</span> dynamics. In this statistical study based on 7 years of Cluster observations, we establish the spatial distributions of oxygen ions and protons at energies from 274 to 955 keV, depending on geomagnetic and solar wind (SW) conditions. Compared with protons, the distribution of energetic oxygen has stronger dawn-dusk asymmetry in response to changes in the geomagnetic activity. When the interplanetary magnetic field (IMF) is directed southward, the oxygen ions show significant acceleration in the tail <span class="hlt">plasma</span> <span class="hlt">sheet</span>. Changes in the SW dynamic pressure (Pdyn) affect the oxygen and proton intensities in the same way. The energetic protons show significant intensity increases at the near-Earth duskside during disturbed geomagnetic conditions, enhanced SW Pdyn, and southward IMF, implying there location of effective inductive acceleration mechanisms and a strong duskward drift due to the increase of the magnetic field gradient in the near-Earth tail. Higher losses of energetic ions are observed in the dayside <span class="hlt">plasma</span> <span class="hlt">sheet</span> under disturbed geomagnetic conditions and enhanced SW Pdyn. These observations are in agreement with theoretical models.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930072240&hterms=irm&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dirm','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930072240&hterms=irm&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dirm"><span id="translatedtitle">Characteristics of ion flow in the quiet state of the inner <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Angelopoulos, V.; Kennel, C. F.; Coroniti, F. V.; Pellat, R.; Spence, H. E.; Kivelson, M. G.; Walker, R. J.; Baumjohann, W.; Feldman, W. C.; Gosling, J. T.</p> <p>1993-01-01</p> <p>We use AMPTE/IRM and ISEE 2 data to study the properties of the high beta <span class="hlt">plasma</span> <span class="hlt">sheet</span>, the inner <span class="hlt">plasma</span> <span class="hlt">sheet</span> (IPS). Bursty bulk flows (BBFs) are excised from the two databases, and the average flow pattern in the non-BBF (quiet) IPS is constructed. At local midnight this ensemble-average flow is predominantly duskward; closer to the flanks it is mostly earthward. The flow pattern agrees qualitatively with calculations based on the Tsyganenko (1987) model (T87), where the earthward flow is due to the ensemble-average cross tail electric field and the duskward flow is the diamagnetic drift due to an inward pressure gradient. The IPS is on the average in pressure equilibrium with the lobes. Because of its large variance the average flow does not represent the instantaneous flow field. Case studies also show that the non-BBF flow is highly irregular and inherently unsteady, a reason why earthward convection can avoid a pressure balance inconsistency with the lobes. The ensemble distribution of velocities is a fundamental observable of the quiet <span class="hlt">plasma</span> <span class="hlt">sheet</span> flow field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950011848&hterms=irm&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dirm','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950011848&hterms=irm&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dirm"><span id="translatedtitle">Bursty bulk flows in the inner central <span class="hlt">plasma</span> <span class="hlt">sheet</span>: An effective means of earthward transport in the magnetotail</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Angelopoulos, Vassilis; Kennel, Charles F.; Coroniti, F. V.; Pellat, R.; Kivelson, M. G.; Walker, R. J.; Baumjohann, W.; Paschmann, G.; Luhr, H.</p> <p>1992-01-01</p> <p>High speed flows in the Earth's Inner Central <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> (ICPS) occur during enhanced flow intervals that have been termed Bursty Bulk Flow (BBF) events. The importance of different flow magnitude samples for Earthward transport in the ICPS are statistically evaluated and several representative BBF's and their relevance to Earthward transport are discussed. The selection of BBF's is automated in a database and they are shown to be responsible for most of the Earthward transport that occurs within the ICPS. The BBF related transport is compared to the transport measured within the entire <span class="hlt">plasma</span> <span class="hlt">sheet</span> during the 1985 AMPTE/IRM crossings of the magnetotail. The results show that BBF's last only a small fraction of the time in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> but can account for several tens of percent of the Earthward particle and energy transfer and possibly all of the Earthward magnetic flux transfer in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22275816','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22275816"><span id="translatedtitle">Graphene <span class="hlt">electron</span> cannon: High-current edge emission from aligned graphene <span class="hlt">sheets</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Liu, Jianlong; Li, Nannan; Guo, Jing; Fang, Yong; Deng, Jiang; Zeng, Baoqing; Wang, Wenzhong; Li, Jiangnan; Hao, Chenchun</p> <p>2014-01-13</p> <p>High-current field emitters are made by graphene paper consist of aligned graphene <span class="hlt">sheets</span>. Field emission luminance pattern shows that their <span class="hlt">electron</span> beams can be controlled by rolling the graphene paper from <span class="hlt">sheet</span> to cylinder. These specific <span class="hlt">electron</span> beams would be useful to vacuum devices and <span class="hlt">electron</span> beam lithograph. To get high-current emission, the graphene paper is rolled to array and form graphene cannon. Due to aligned emission array, graphene cannon have high emission current. Besides high emission current, the graphene cannon is also tolerable with excellent emission stability. With good field emission properties, these aligned graphene emitters bring application insight.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850000068&hterms=silicone&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dsilicone','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850000068&hterms=silicone&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dsilicone"><span id="translatedtitle">Silicone Coating on Polyimide <span class="hlt">Sheet</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Park, J. J.</p> <p>1985-01-01</p> <p>Silicone coatings applied to polyimide <span class="hlt">sheeting</span> for variety of space-related applications. Coatings intended to protect flexible substrates of solar-cell blankets from degradation by oxygen atoms, <span class="hlt">electrons</span>, <span class="hlt">plasmas</span>, and ultraviolet light in low Earth orbit and outer space. Since coatings are flexible, generally useful in forming flexible laminates or protective layers on polyimide-<span class="hlt">sheet</span> products.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110015845','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110015845"><span id="translatedtitle">Effect of Inductive Coil Geometry and Current <span class="hlt">Sheet</span> Trajectory of a Conical Theta Pinch Pulsed Inductive <span class="hlt">Plasma</span> Accelerator</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hallock, Ashley K.; Polzin, Kurt A.; Bonds, Kevin W.; Emsellem, Gregory D.</p> <p>2011-01-01</p> <p>Results are presented demonstrating the e ect of inductive coil geometry and current <span class="hlt">sheet</span> trajectory on the exhaust velocity of propellant in conical theta pinch pulsed induc- tive <span class="hlt">plasma</span> accelerators. The electromagnetic coupling between the inductive coil of the accelerator and a <span class="hlt">plasma</span> current <span class="hlt">sheet</span> is simulated, substituting a conical copper frustum for the <span class="hlt">plasma</span>. The variation of system inductance as a function of <span class="hlt">plasma</span> position is obtained by displacing the simulated current <span class="hlt">sheet</span> from the coil while measuring the total inductance of the coil. Four coils of differing geometries were employed, and the total inductance of each coil was measured as a function of the axial displacement of two sep- arate copper frusta both having the same cone angle and length as the coil but with one compressed to a smaller size relative to the coil. The measured relationship between total coil inductance and current <span class="hlt">sheet</span> position closes a dynamical circuit model that is used to calculate the resulting current <span class="hlt">sheet</span> velocity for various coil and current <span class="hlt">sheet</span> con gura- tions. The results of this model, which neglects the pinching contribution to thrust, radial propellant con nement, and plume divergence, indicate that in a conical theta pinch ge- ometry current <span class="hlt">sheet</span> pinching is detrimental to thruster performance, reducing the kinetic energy of the exhausting propellant by up to 50% (at the upper bound for the parameter range of the study). The decrease in exhaust velocity was larger for coils and simulated current <span class="hlt">sheets</span> of smaller half cone angles. An upper bound for the pinching contribution to thrust is estimated for typical operating parameters. Measurements of coil inductance for three di erent current <span class="hlt">sheet</span> pinching conditions are used to estimate the magnetic pressure as a function of current <span class="hlt">sheet</span> radial compression. The gas-dynamic contribution to axial acceleration is also estimated and shown to not compensate for the decrease in axial electromagnetic acceleration that accompanies the radial compression of the <span class="hlt">plasma</span> in conical theta pinches.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5156633','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5156633"><span id="translatedtitle">Temperature limit in ECH hot <span class="hlt">electron</span> <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Uckan, N.A.</p> <p>1982-06-01</p> <p>During the last two decades the production of high-beta, hot <span class="hlt">electron</span> <span class="hlt">plasmas</span> with <span class="hlt">electron</span> cyclotron heating (ECH) has been amply demonstrated in open and closed geometries. A wide variety of conditions was present in these experiments with a factor of 2 change in device dimensions and more than an order of magnitude change in magnetic fields (approx. 1 to 10 kG), ECH frequencies (approx. 6 to 55 GHz), and hot <span class="hlt">electron</span> temperatures (approx. 50 to 1200 keV). An analysis of the data from all the experiments that used single ECH frequency indicates that the hot <span class="hlt">electron</span> temperatures do increase with magnetic field strength (or, equivalently, ECH frequency) and scale length. In particular, they all obey rho/L approx. = constant (approx. 5 to 6 x 10/sup -2/) scaling, where rho and L are the hot <span class="hlt">electron</span> gyroradius (relativistic) and the magnetic field scale length, respectively. This is roughly the value at which conservationof the adiabatic invariant ..mu.. begins to break down and suggests that the hot <span class="hlt">electron</span> temperatures are probably limited by nonadiabatic particle behavior. Results, primarily from hot <span class="hlt">electron</span> ring experiments (ELMO, EBT, NBT, etc.), are discussed, and projections for future experiments are given. It is shown that although in all previous experiments the ring temperature is determined by the rho/L criterion EBT-P will be the first experiment unconstrained by this limit.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930071545&hterms=collective+modes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dcollective%2Bmodes','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930071545&hterms=collective+modes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dcollective%2Bmodes"><span id="translatedtitle">Ion mixing in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer by drift instabilities</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Horton, W.; Dong, J. Q.; Su, X. N.; Tajima, T.</p> <p>1993-01-01</p> <p>The linear stability properties of collisionless drift instabilities are analyzed in a Harris equilibrium model of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer (PSBL). The strearmng ions with drift-type instabilities driven in the PSBL are considered. The fluid approximation leads to growth but predicts that the mode width approaches the gyroradius of the energetic ions. Thus an integral equation theory for the modes is developed taking into account that in the PSBL the curvature drift is weak compared with the grad-B drift. The exact wave particle resonance is kept in the nonlocal response functions. <span class="hlt">Plasma</span> density, temperature, and magnetic gradient drift motions are taken into account. The drift modes produce an anomalous cross-field momentum transport mixing the PSBL ions on the time scale of tens of seconds. A nonlinear simulation is performed which shows the coalescence of the small scale, fast growing modes into large-scale vortices. The relation between these collective modes and <span class="hlt">plasma</span> <span class="hlt">sheet</span> transport phenomena is discussed including the comparison with the competing <span class="hlt">plasma</span> mixing from single-particle stochasticity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMSM14B..05Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMSM14B..05Y"><span id="translatedtitle">Investigating the role of the entropy parameter in <span class="hlt">plasma</span> <span class="hlt">sheet</span> dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, J.; Toffoletto, F.; Wolf, R. A.; Sazykin, S.; Hu, B.; Raeder, J.</p> <p>2011-12-01</p> <p>Representing a combination of mass and entropy, the entropy parameter PV5/3 is approximately conserved for <span class="hlt">plasma</span> <span class="hlt">sheet</span> flux tubes and proves very useful for understanding <span class="hlt">plasma</span> <span class="hlt">sheet</span> dynamics. (Here P is <span class="hlt">plasma</span> pressure and V is the volume of a flux tube containing one unit of magnetic flux). Under quasi-static-equilibrium conditions, PV5/3 determines Birkeland currents and interchange instability. It is consequently a key parameter for physical interpretation of results from RCM and RCM-E. The appropriate generalization of PV5/3 for conditions when P is not constant along a field line is the 5/3 power of the flux-tube integral of P3/5. That parameter is conserved in ideal MHD and is useful in physical interpretation of MHD simulations of the magnetosphere. We present recent computer experiments to investigate how the values of PV5/3 in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> can affect the <span class="hlt">plasma</span> transport and field configuration during various geomagnetic active times. A comparative study of RCM-E simulations shows that persistent steady magnetospheric convection during strong polar cap potential drops is possible if the flux tubes in the magnetotail are substantially depleted along a sector with very wide local times; otherwise, the magnetic field will gradually become highly stretched if the inner magnetosphere is fed with relatively high entropy <span class="hlt">plasma</span>, resembling the substorm growth phase. In the end of the growth phase, resistive MHD simulations using OpenGGCM indicate that the violation of frozen-in-flux condition can give rise to the formation of a bubble (lower PV5/3 than its neighbors) earthward of a blob (higher PV5/3 than its neighbors). Both OpenGGCM and RCM-E results show that the earthward motion of the bubble and the tailward motion of the blob lead to a reduction of the normal magnetic field between them, which thins the current <span class="hlt">sheet</span> rapidly. Substorm injection simulations are carried out using RCM-E by placing bubbles on the tailward boundary for both non-storm and storm times. A variety of aspects associated with the bubble injections will be discussed, including the classic substorm injection boundary problem, the reconfiguration of large-scale current systems and the magnetic disturbance in ground magnetograms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMSM32A..01L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMSM32A..01L"><span id="translatedtitle">Polar Cap Convection Structures: Relations to High Speed Streams and <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> Dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lyons, L. R.; Nishimura, T.; Kim, H.; Angelopoulos, V.; Heinselman, C. J.; Ruohoniemi, J. M.; Sofko, G. J.; Donovan, E.</p> <p>2011-12-01</p> <p>The orientation and magnitude of the interplanetary magnetic field (IMF) and solar wind dynamic pressure are well known to affect the strength of convection. However, radar measurements of high-latitude ionospheric convection show evidence that ULF power in the IMF has an additional substantial effect on the strength of convection within the polar caps, and on the nightside within both the aurora ionosphere and the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. Convection flows during periods of large north-south IMF fluctuations are observed to be as strong as for steady and large southward IMF periods, and substantially enhanced convection is observed for northward IMF intervals when the IMF exhibits high ULF power. Since ULF power is particularly high during high-speed solar wind streams (HSS), these effects are particularly important and likely a major contributor to disturbances within the magnetosphere-ionosphere-thermosphere system during HSS. However, observations during periods of Alfvnic magnetic fluctuations without high-speed solar wind indicate that the enhanced flows are at least in part directly due to the Alfvnic magnetic fluctuations and are not solely due to the high-speed solar wind. We furthermore find that the enhanced polar-cap convection driven by the ULF power in the solar wind is highly structured in time, and is associated with many substorms, including during periods of northward IMF. A possible cause of the connection to convection and disturbances within the <span class="hlt">plasma</span> <span class="hlt">sheet</span> is indicated by recent radar observations of flows within the polar cap. The observations suggest that meso-scale flow channels from deep within the region of open polar cap field lines may cross the nightside polar cap boundary into the closed field line region and contribute to the triggering of equatorward (earthward) meso-scale flows across the ionospheric (equatorial) end of <span class="hlt">plasma</span> <span class="hlt">sheet</span> fields lines and lead to PBIs and streamers. This includes the streamers that have been postulated to bring new <span class="hlt">plasma</span> equatorward (earthward) and lead to substorm onset. Such a connection offers an explanation for the enhanced convection, <span class="hlt">plasma</span> pressures, and substorm activity that has been observed within the <span class="hlt">plasma</span> <span class="hlt">sheet</span> during periods of enhanced ULF fluctuations, including during HSS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4431294','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4431294"><span id="translatedtitle">Detection of Steel Fatigue Cracks with Strain Sensing <span class="hlt">Sheets</span> Based on Large Area <span class="hlt">Electronics</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Yao, Yao; Glisic, Branko</p> <p>2015-01-01</p> <p>Reliable early-stage damage detection requires continuous monitoring over large areas of structure, and with sensors of high spatial resolution. Technologies based on Large Area <span class="hlt">Electronics</span> (LAE) can enable direct sensing and can be scaled to the level required for Structural Health Monitoring (SHM) of civil structures and infrastructure. Sensing <span class="hlt">sheets</span> based on LAE contain dense arrangements of thin-film strain sensors, associated <span class="hlt">electronics</span> and various control circuits deposited and integrated on a flexible polyimide substrate that can cover large areas of structures. This paper presents the development stage of a prototype strain sensing <span class="hlt">sheet</span> based on LAE for crack detection and localization. Two types of sensing-<span class="hlt">sheet</span> arrangements with size 6 × 6 inch (152 × 152 mm) were designed and manufactured, one with a very dense arrangement of sensors and the other with a less dense arrangement of sensors. The sensing <span class="hlt">sheets</span> were bonded to steel plates, which had a notch on the boundary, so the fatigue cracks could be generated under cyclic loading. The sensors within the sensing <span class="hlt">sheet</span> that were close to the notch tip successfully detected the initialization of fatigue crack and localized the damage on the plate. The sensors that were away from the crack successfully detected the propagation of fatigue cracks based on the time history of the measured strain. The results of the tests have validated the general principles of the proposed sensing <span class="hlt">sheets</span> for crack detection and identified advantages and challenges of the two tested designs. PMID:25853407</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25853407','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25853407"><span id="translatedtitle">Detection of steel fatigue cracks with strain sensing <span class="hlt">sheets</span> based on large area <span class="hlt">electronics</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yao, Yao; Glisic, Branko</p> <p>2015-01-01</p> <p>Reliable early-stage damage detection requires continuous monitoring over large areas of structure, and with sensors of high spatial resolution. Technologies based on Large Area <span class="hlt">Electronics</span> (LAE) can enable direct sensing and can be scaled to the level required for Structural Health Monitoring (SHM) of civil structures and infrastructure. Sensing <span class="hlt">sheets</span> based on LAE contain dense arrangements of thin-film strain sensors, associated <span class="hlt">electronics</span> and various control circuits deposited and integrated on a flexible polyimide substrate that can cover large areas of structures. This paper presents the development stage of a prototype strain sensing <span class="hlt">sheet</span> based on LAE for crack detection and localization. Two types of sensing-<span class="hlt">sheet</span> arrangements with size 6 × 6 inch (152 × 152 mm) were designed and manufactured, one with a very dense arrangement of sensors and the other with a less dense arrangement of sensors. The sensing <span class="hlt">sheets</span> were bonded to steel plates, which had a notch on the boundary, so the fatigue cracks could be generated under cyclic loading. The sensors within the sensing <span class="hlt">sheet</span> that were close to the notch tip successfully detected the initialization of fatigue crack and localized the damage on the plate. The sensors that were away from the crack successfully detected the propagation of fatigue cracks based on the time history of the measured strain. The results of the tests have validated the general principles of the proposed sensing <span class="hlt">sheets</span> for crack detection and identified advantages and challenges of the two tested designs. PMID:25853407</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997APS..DPPkWP102S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997APS..DPPkWP102S"><span id="translatedtitle">A Toroidal Pure <span class="hlt">Electron</span> <span class="hlt">Plasma</span> Experiment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stoneking, Matthew R.</p> <p>1997-11-01</p> <p>A non-neutral (<span class="hlt">electron</span>) <span class="hlt">plasma</span> physics experiment in toroidal geometry is described. Equilibrium for a charged <span class="hlt">plasma</span> in a toroidal magnetic field is provided by an electric field in the major radial direction.(J. D. Daugherty and R. H. Levy, Phys. Fluids 10), 155 (1967) The experiment under construction will focus on equilibrium requirements, stability, and confinement limitations. Poloidal angular momentum will be supplied with a rotating electric field perturbation, a technique was successfully applied to cylindrical non-neutral <span class="hlt">plasmas</span>.(X.-P. Huang et al., Phys. Rev. Lett. 78), 875 (1997) The initial design uses a `C'-shaped partially toroidal confinement region. End-cell electrodes are used (as in Malmberg traps) to permit charge injection onto field lines tied to the trapping region and to permit diagnostic dumping of the <span class="hlt">plasma</span>. A low magnitude, D.C. field (100 -- 200 G) and high aspect ratio (R_o/a ? 10) also constitute part of the initial design. The experiment is sited at a small liberal arts college and will provide opportunities for undergraduate research. This work is supported by Research Corporation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26726645','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26726645"><span id="translatedtitle">Unzipped Nanotube <span class="hlt">Sheet</span> Films Converted from Spun Multi-Walled Carbon Nanotubes by O2 <span class="hlt">Plasma</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jangr, Hoon-Sik; Jeon, Sang Koo; Shim, Dae Seob; Lee, Nam Hee; Nahm, Seung Hoon</p> <p>2015-11-01</p> <p>Large-scale graphene or carbon nanotube (CNT) films are good candidates for transparent flexible electrodes, and the strong interest in graphene and CNT films has motivated the scalable production of a good-conductivity and an optically transmitting film. Unzipping techniques for converting CNTs to graphene are especially worthy of notice. Here, we performed nanotube unzipping of the spun multi-walled carbon nanotubes (MWCNTs) to produce networked graphene nanoribbon (GNR) <span class="hlt">sheet</span> films using an 02 <span class="hlt">plasma</span> etching method, after which we produced the spun MWCNT film by continually pulling MWCNTs down from the vertical well aligned MWCNTs on the substrate. The electrical resistance was slightly decreased and the optical transmittance was significantly increased when the spun MWCNT films were etched for 20 min by O2 <span class="hlt">plasma</span> of 100 mA. <span class="hlt">Plasma</span> etching for the optimized time, which does not change the thickness of the spun MWCNT films, improved the electrical resistance and the optical transmittance. PMID:26726645</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9435E..0GY','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9435E..0GY"><span id="translatedtitle">Sensing <span class="hlt">sheets</span> based on large area <span class="hlt">electronics</span> for fatigue crack detection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yao, Yao; Glisic, Branko</p> <p>2015-03-01</p> <p>Reliable early-stage damage detection requires continuous structural health monitoring (SHM) over large areas of structure, and with high spatial resolution of sensors. This paper presents the development stage of prototype strain sensing <span class="hlt">sheets</span> based on Large Area <span class="hlt">Electronics</span> (LAE), in which thin-film strain gauges and control circuits are integrated on the flexible <span class="hlt">electronics</span> and deposited on a polyimide <span class="hlt">sheet</span> that can cover large areas. These sensing <span class="hlt">sheets</span> were applied for fatigue crack detection on small-scale steel plates. Two types of sensing-<span class="hlt">sheet</span> interconnects were designed and manufactured, and dense arrays of strain gauge sensors were assembled onto the interconnects. In total, four (two for each design type) strain sensing <span class="hlt">sheets</span> were created and tested, which were sensitive to strain at virtually every point over the whole sensing <span class="hlt">sheet</span> area. The sensing <span class="hlt">sheets</span> were bonded to small-scale steel plates, which had a notch on the boundary so that fatigue cracks could be generated under cyclic loading. The fatigue tests were carried out at the Carleton Laboratory of Columbia University, and the steel plates were attached through a fixture to the loading machine that applied cyclic fatigue load. Fatigue cracks then occurred and propagated across the steel plates, leading to the failure of these test samples. The strain sensor that was close to the notch successfully detected the initialization of fatigue crack and localized the damage on the plate. The strain sensor that was away from the crack successfully detected the propagation of fatigue crack based on the time history of measured strain. Overall, the results of the fatigue tests validated general principles of the strain sensing <span class="hlt">sheets</span> for crack detection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/doepatents/biblio/874126','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/doepatents/biblio/874126"><span id="translatedtitle"><span class="hlt">Plasma</span> treatment for producing <span class="hlt">electron</span> emitters</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Coates, Don Mayo (Santa Fe, NM); Walter, Kevin Carl (Los Alamos, NM)</p> <p>2001-01-01</p> <p><span class="hlt">Plasma</span> treatment for producing carbonaceous field emission <span class="hlt">electron</span> emitters is disclosed. A <span class="hlt">plasma</span> of ions is generated in a closed chamber and used to surround the exposed surface of a carbonaceous material. A voltage is applied to an electrode that is in contact with the carbonaceous material. This voltage has a negative potential relative to a second electrode in the chamber and serves to accelerate the ions toward the carbonaceous material and provide an ion energy sufficient to etch the exposed surface of the carbonaceous material but not sufficient to result in the implantation of the ions within the carbonaceous material. Preferably, the ions used are those of an inert gas or an inert gas with a small amount of added nitrogen.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22093525','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22093525"><span id="translatedtitle"><span class="hlt">Electron</span>-helium scattering in Debye <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zammit, Mark C.; Fursa, Dmitry V.; Bray, Igor; Janev, R. K.</p> <p>2011-11-15</p> <p><span class="hlt">Electron</span>-helium scattering in weakly coupled hot-dense (Debye) <span class="hlt">plasma</span> has been investigated using the convergent close-coupling method. The Yukawa-type Debye-Hueckel potential has been used to describe <span class="hlt">plasma</span> Coulomb screening effects. Benchmark results are presented for momentum transfer cross sections, excitation, ionization, and total cross sections for scattering from the ground and metastable states of helium. Calculations cover the entire energy range up to 1000 eV for the no screening case and various Debye lengths (5-100 a{sub 0}). We find that as the screening interaction increases, the excitation and total cross sections decrease, while the total ionization cross sections increase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFMSH32C..03S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFMSH32C..03S"><span id="translatedtitle">Whistler-mode phenomena in <span class="hlt">electron</span> MHD <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stenzel, R. L.</p> <p>2003-12-01</p> <p>While the linear properties of plane whistler waves are well known, many new phenomena of bounded wavepackets and nonlinear effects are worth to describe. The present talk will review laboratory observations of whistler filaments, whistler vortices, whistler wings, whistler-sound modes in high-beta <span class="hlt">plasmas</span>, nonlinear whistlers forming magnetic null points, and magnetic reconnection in EMHD <span class="hlt">plasmas</span>. The time-varying magnetic field of a spatially bounded whistler wave packet consists of 3-D vortices. Each vortex can be decomposed into linked toroidal and poloidal field components. The self-helicity is positive for propagation along the field, negative for opposite propagation. Helicity injection from a suitable source produces unidirectional propagation. Magnetic helicity changes sign, i.e., is not conserved, when the propagation direction along B changes, for example due to reflection or propagation through a magnetic null point. In ideal EMHD the electric and magnetic forces on the <span class="hlt">electrons</span> are equal, -n e E +J x B=0, i.e., the <span class="hlt">electron</span> fluid is not compressed. Force-free vortices do not interact during collisions. Vortices are excited with pulsed magnetic antennas or pulsed electrodes. Both transient currents and fields can form vortices that propagate in the whistler mode. Moving dc magnets or dc current systems can also induce whistler modes in a magnetized <span class="hlt">plasma</span>. These form a Cherenkov-like radiation pattern, a ``whistler wing.'' Nonlinear phenomena arise from wave-induced modifications of the <span class="hlt">electron</span> temperature, density and magnetic field. In collisional <span class="hlt">plasmas</span> <span class="hlt">electrons</span> are heated by strong whistlers. Modifications of the classical conductivity leads to current filamentation. On a slower time scale density modifications arise from ambipolar fields associated with <span class="hlt">electron</span> heating. In a filamentation instability a strong whistler wave is ducted along a narrow field-aligned density depression. The ion density is also modified by the ac electric field of low-frequency whistlers in high-beta <span class="hlt">plasmas</span>. Pressure-gradient driven instabilities near the lower hybrid frequency produce coupled density and magnetic perturbations that propagate at the sound speed nearly across the field, forming a new whistler-sound mode. The net magnetic field is modified when the whistler magnetic field exceeds the background magnetic field. A field-reversed configuration (FRC) with two 3-D null points is produced. This EMHD structure does not propagate in the whistler mode. It elongates and precesses, which are manifestations of magnetic fields frozen into the <span class="hlt">electron</span> fluid flow. The free magnetic energy is converted into <span class="hlt">electron</span> heat by field line annihilation in the toroidal current <span class="hlt">sheet</span>. No reconnection is seen at the 3-D spiral nulls. The energy dissipation is anomalously fast due to current-driven ion sound turbulence. In contrast to linear vortices, two FRCs do interact and merge into a single one. These basic properties of EMHD fields will be applied to cases of interest in space <span class="hlt">plasmas</span> such as reconnection, strong turbulence, and possible active experiments. Work performed in collaboration with J.~M. Urrutia, M.~C. Griskey, and K.~D. Strohmaier with support from NSF PHY.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1048437','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1048437"><span id="translatedtitle"><span class="hlt">Electron</span> Recombination in a Dense Hydrogen <span class="hlt">Plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jana, M.R.; Johnstone, C.; Kobilarcik, T.; Koizumi, G.M.; Moretti, A.; Popovic, M.; Tollestrup, A.V.; Yonehara, K.; Leonova, M.A.; Schwarz, T.A.; Chung, M.; /Unlisted /IIT, Chicago /Fermilab /MUONS Inc., Batavia /Turin Polytechnic</p> <p>2012-05-01</p> <p>A high pressure hydrogen gas filled RF cavity was subjected to an intense proton beam to study the evolution of the beam induced <span class="hlt">plasma</span> inside the cavity. Varying beam intensities, gas pressures and electric fields were tested. Beam induced ionized <span class="hlt">electrons</span> load the cavity, thereby decreasing the accelerating gradient. The extent and duration of this degradation has been measured. A model of the recombination between ionized <span class="hlt">electrons</span> and ions is presented, with the intent of producing a baseline for the physics inside such a cavity used in a muon accelerator. Analysis of the data taken during the summer of 2011 shows that self recombination takes place in pure hydrogen gas. The decay of the number of <span class="hlt">electrons</span> in the cavity once the beam is turned off indicates self recombination rather than attachment to electronegative dopants or impurities. The cross section of <span class="hlt">electron</span> recombination grows for larger clusters of hydrogen and so at the equilibrium of <span class="hlt">electron</span> production and recombination in the cavity, processes involving H{sub 5}{sup +} or larger clusters must be taking place. The measured recombination rates during this time match or exceed the analytic predicted values. The accelerating gradient in the cavity recovers fully in time for the next beam pulse of a muon collider. Exactly what the recombination rate is and how much the gradient degrades during the 60 ns muon collider beam pulse will be extrapolated from data taken during the spring of 2012.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5117668','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5117668"><span id="translatedtitle"><span class="hlt">Plasma</span> heating by a relativistic <span class="hlt">electron</span> beam</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Janssen, G.C.A.M.; Bonnie, J.H.M.; Granneman, E.H.A.; Krementsov, V.I.; Hopman, H.J.</p> <p>1984-03-01</p> <p>Reported are measurements on the interaction between a relativistic <span class="hlt">electron</span> beam (REB) with the parameters 800 kV, 6 kA, 50--150 nsec, and a <span class="hlt">plasma</span> with a density of n/sub e/ = 1.0 x 10/sup 19/ m/sup -3/--1.0 x 10/sup 20/ m/sup -3/. The <span class="hlt">electron</span> temperature during and after the beam pulse is obtained by means of Thomson scattering. Also measured is the angular distribution of the beam <span class="hlt">electrons</span> as a function of time and position. By varying the angular spread of the beam it is possible to pass from a kinetic to a quasihydrodynamic interaction. In both regimes measurements are compared with the appropriate theoretical model. Energy transfer is largest in the quasihydrodynamic regime and amounts to 2.5 x 10/sup 3/ J/m/sup 3/ or 2.2 x 10/sup 16/ eV/cm/sup 3/. The <span class="hlt">electron</span> temperature reaches values of 150 eV and appears limited by the <span class="hlt">electron</span> heat conduction along the magnetic field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/896940','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/896940"><span id="translatedtitle">Energy Measurements of Trapped <span class="hlt">Electrons</span> from a <span class="hlt">Plasma</span> Wakefield Accelerator</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kirby, Neal; Auerbach, David; Berry, Melissa; Blumenfeld, Ian; Clayton, Christopher E.; Decer, Franz-Josef; Hogan, Mark J.; Huang, Chengkun; Ischebeck, Rasmus; Iverson, Richard; Johnson, Devon; Joshi, Chadrashekhar; Katsouleas, Thomas; Lu, Wei; Marsh, Kenneth A.; Mori, Warren B.; Muggli, Patric; Oz, Erdem; Siemann, Robert H.; Walz, Dieter; Zhou, Miaomiao; /SLAC /UCLA /Southern California U.</p> <p>2007-01-03</p> <p>Recent <span class="hlt">electron</span> beam driven <span class="hlt">plasma</span> wakefield accelerator experiments carried out at SLAC indicate trapping of <span class="hlt">plasma</span> <span class="hlt">electrons</span>. More charge came out of than went into the <span class="hlt">plasma</span>. Most of this extra charge had energies at or below the 10 MeV level. In addition, there were trapped <span class="hlt">electron</span> streaks that extended from a few GeV to tens of GeV, and there were mono-energetic trapped <span class="hlt">electron</span> bunches with tens of GeV in energy.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22086170','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22086170"><span id="translatedtitle">A research of W-band folded waveguide traveling wave tube with elliptical <span class="hlt">sheet</span> <span class="hlt">electron</span> beam</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Guo Guo; Wei Yanyu; Yue Lingna; Gong Yubin; Zhao Guoqing; Huang Minzhi; Tang Tao; Wang Wenxiang</p> <p>2012-09-15</p> <p>Folded waveguide (FWG) traveling wave tube (TWT), which shows advantages in high power capacity, moderate bandwidth, and low-cost fabrication, has become the focus of vacuum <span class="hlt">electronics</span> recently. <span class="hlt">Sheet</span> <span class="hlt">electron</span> beam devices are better suited for producing radiation sources with large power in millimeter wave spectrum due to their characteristics of relatively low space charge fields and large transport current. A FWG TWT with elliptical <span class="hlt">sheet</span> beam working in W-band is presented in this paper, with the analysis of its dispersion characteristics, coupling impedance, transmission properties, and interaction characteristics. A comparison is also made with the traditional FWG TWT. Simulation results lead to the conclusion that the FWG TWT with elliptical <span class="hlt">sheet</span> beam investigated in this paper can make full use of relatively large electric fields and thus generate large output power with the same electric current density.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhPl...19i3117G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhPl...19i3117G"><span id="translatedtitle">A research of W-band folded waveguide traveling wave tube with elliptical <span class="hlt">sheet</span> <span class="hlt">electron</span> beam</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guo, Guo; Wei, Yanyu; Yue, Lingna; Gong, Yubin; Zhao, Guoqing; Huang, Minzhi; Tang, Tao; Wang, Wenxiang</p> <p>2012-09-01</p> <p>Folded waveguide (FWG) traveling wave tube (TWT), which shows advantages in high power capacity, moderate bandwidth, and low-cost fabrication, has become the focus of vacuum <span class="hlt">electronics</span> recently. <span class="hlt">Sheet</span> <span class="hlt">electron</span> beam devices are better suited for producing radiation sources with large power in millimeter wave spectrum due to their characteristics of relatively low space charge fields and large transport current. A FWG TWT with elliptical <span class="hlt">sheet</span> beam working in W-band is presented in this paper, with the analysis of its dispersion characteristics, coupling impedance, transmission properties, and interaction characteristics. A comparison is also made with the traditional FWG TWT. Simulation results lead to the conclusion that the FWG TWT with elliptical <span class="hlt">sheet</span> beam investigated in this paper can make full use of relatively large electric fields and thus generate large output power with the same electric current density.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JGRA..115.9220O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JGRA..115.9220O"><span id="translatedtitle">Distribution of O+ ions in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and locations of substorm onsets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ono, Y.; Christon, S. P.; Frey, H. U.; Lui, A. T. Y.</p> <p>2010-09-01</p> <p>We discuss the effect of O+ ions on substorm onsets by examining the relation between the substorm onset location and the distribution of the O+/H+ number density ratio before the onset in the various regions within the <span class="hlt">plasma</span> <span class="hlt">sheet</span> (-8 RE > XGSM > -32 RE). We use 9-212 keV/e ion flux data observed by Geotail/Energetic Particles and Ion Composition (EPIC)/Suprathermal Ion Composition Spectrometer (STICS) instrument and the IMAGE/Far Ultra-Violet (FUV) substorm onset list presented by Frey et al. [Frey, H. U., S. B. Mende, V. Angelopoulos, and E. F. Donovan (2004), Substorm onset observations by IMAGE-FUV, J. Geophys. Res., 109, A10304, doi:10.1029/2004JA010607]. The results are summarized as follows. Substorm onsets, which we identify by auroral initial brightenings, are likely to occur in the more dusk-(dawn-)ward region when the O+/H+ number density ratio is high in the dusk (dawn) side. This property is observed only in the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> (at -8 RE > XGSM > -14 RE). The above-mentioned property holds in each of two groups: substorm events due to internal instability of the magnetosphere (i.e., internally triggered substorms) and events due to external changes in the solar wind or the interplanetary magnetic field (i.e., externally triggered substorms). Thus, we conclude that the substorm onset location depends on the density of O+ ions in the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> prior to onset, whether the substorm is triggered internally or externally.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1193626','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1193626"><span id="translatedtitle">Fact <span class="hlt">Sheet</span> for KM200 Front-end <span class="hlt">Electronics</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ianakiev, Kiril Dimitrov; Iliev, Metodi; Swinhoe, Martyn Thomas</p> <p>2015-07-08</p> <p>The KM200 device is a versatile, configurable front-end <span class="hlt">electronics</span> boards that can be used as a functional replacement for Canberra’s JAB-01 boards based on the Amptek A-111 hybrid chip, which continues to be the preferred choice of <span class="hlt">electronics</span> for large number of the boards in junction boxes of multiplicity counters that process the signal from an array of 3He detectors. Unlike the A-111 chip’s fixed time constants and sensitivity range, the shaping time and sensitivity of the new KM200 can be optimized for demanding applications such as spent fuel, and thus could improve the safeguards measurements of existing systems where the A-111 or PDT <span class="hlt">electronics</span> does not perform well.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24720450','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24720450"><span id="translatedtitle">Increased tensile strength of carbon nanotube yarns and <span class="hlt">sheets</span> through chemical modification and <span class="hlt">electron</span> beam irradiation.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Miller, Sandi G; Williams, Tiffany S; Baker, James S; Sol, Francisco; Lebron-Colon, Marisabel; McCorkle, Linda S; Wilmoth, Nathan G; Gaier, James; Chen, Michelle; Meador, Michael A</p> <p>2014-05-14</p> <p>The inherent strength of individual carbon nanotubes (CNTs) offers considerable opportunity for the development of advanced, lightweight composite structures. Recent work in the fabrication and application of CNT forms such as yarns and <span class="hlt">sheets</span> has addressed early nanocomposite limitations with respect to nanotube dispersion and loading and has pushed the technology toward structural composite applications. However, the high tensile strength of an individual CNT has not directly translated into that of <span class="hlt">sheets</span> and yarns, where the bulk material strength is limited by intertube electrostatic attractions and slippage. The focus of this work was to assess postprocessing of CNT <span class="hlt">sheets</span> and yarns to improve the macro-scale strength of these material forms. Both small-molecule functionalization and <span class="hlt">electron</span>-beam irradiation were evaluated as means to enhance the tensile strength and Young's modulus of the bulk CNT materials. Mechanical testing revealed a 57% increase in tensile strength of CNT <span class="hlt">sheets</span> upon functionalization compared with unfunctionalized <span class="hlt">sheets</span>, while an additional 48% increase in tensile strength was observed when functionalized <span class="hlt">sheets</span> were irradiated. Similarly, small-molecule functionalization increased tensile strength of yarn by up to 25%, whereas irradiation of the functionalized yarns pushed the tensile strength to 88% beyond that of the baseline yarn. PMID:24720450</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20797888','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20797888"><span id="translatedtitle">Relativistic <span class="hlt">Electron</span> Beam Interaction With Semi-Bounded <span class="hlt">Plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Barchuk, S. V.; Lapshin, V. I.; Harchenko, A. O.; Maslov, V. I</p> <p>2006-01-15</p> <p>In this paper we theoretically investigate phenomenon experimentally observed in [2]: reflection of a relativistic <span class="hlt">electron</span> beam of finite length and small radius from vacuum-<span class="hlt">plasma</span> boundary. We suppose that self-focusing of <span class="hlt">electron</span> beam has been finished. The <span class="hlt">electron</span> beam reflection on <span class="hlt">electron</span> time scale is also considered. So <span class="hlt">plasma</span> ions are fixed in space, but <span class="hlt">plasma</span> <span class="hlt">electrons</span> are accelerated in transversal direction. Thus a positive charge appears around the beam. The longitudinal shape of the electric potential is formed by <span class="hlt">electron</span> beam and positive charge at separation of the beam back front from the <span class="hlt">plasma</span> boundary. It was shown that this electric potential profile can be cause of reflection of an <span class="hlt">electron</span> beam part from the <span class="hlt">plasma</span> boundary. Dependence of the electric potential profile from a beam penetration depth and ratio of the <span class="hlt">plasma</span> and beam parameters are obtained.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003PhDT........12U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003PhDT........12U"><span id="translatedtitle"><span class="hlt">Electron</span> temperature dynamics of TEXTOR <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Udintsev, Victor Sergeevich</p> <p>2003-11-01</p> <p>To study <span class="hlt">plasma</span> properties in the presence of large and small MHD modes, new high-resolution ECE diagnostics have been installed at TEXTOR tokamak, and some of the already existing systems have been upgraded. Two models for the <span class="hlt">plasma</span> transport properties inside large m/n = 2/1 MHD islands have been found to give estimations for the heat diffusivities, which are much lower than the global <span class="hlt">plasma</span> heat diffusivity, which is in agreement with previous measurements in different tokamaks. The 3D-reconstruction of large m/n = 2/1 modes in TEXTOR with the help of all available ECE diagnostics allows modelling the island as a structure with closed flux surfaces. The main <span class="hlt">plasma</span> heat flux flows through the X-point area probably along stochastic magnetic field lines. The confinement is improved within the magnetic island, compared to the background <span class="hlt">plasma</span>. This is confirmed by a temperature profile flattening and sometimes even a secondary peaking inside the island, compared to the X-point. Making use of the mode rotation, assumed to be a rigid rotor, it has been possible to obtain information on the topology of the m = 1 precursor mode leading to sawtooth collapses. It becomes clear that this precursor cannot be described by an m = 1 cold tearing mode island but by a hot crescent wrapped around a cold high-density bubble. In the future multi-chord ECE-imaging will allow this mode reconstruction without the assumption of the rotation to be rigid. From the measurements of the broadband temperature and density fluctuations one can conclude that the turbulent structures inside the q = 1 surface are separated from the turbulence outside the q = 1 surface. This fits nicely with the observation that q = 1 surface acts as a barrier for the thermal transport. Correlation length and time measured inside q = 1 are in agreement with the observed turbulent heat diffusivity. Qualitative studies of non-thermal <span class="hlt">electrons</span> at different heating regimes (ECRH and Ohmic) at TEXTOR were done with the help of the combined 2nd -3rd harmonic X-mode ECE radiometer. It has been found that the lower energetic non-thermal <span class="hlt">electrons</span> are directly responsive to small density changes, in contrast to the highly energetic runaways with energy up to 20 MeV. Those are only affected by a substantial density ramp up.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5702177','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5702177"><span id="translatedtitle">Flute-interchange stability in a hot <span class="hlt">electron</span> <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Dominguez, R.R.</p> <p>1980-01-01</p> <p>Several topics in the kinetic stability theory of flute-interchange modes in a hot <span class="hlt">electron</span> <span class="hlt">plasma</span> are discussed. The stability analysis of the hot-<span class="hlt">electron</span>, curvature-driven flute-interchange mode, previously performed in a slab geometry, is extended to a cylindrical <span class="hlt">plasma</span>. The cold <span class="hlt">electron</span> concentration necessary for stability differs substantially from previous criteria. The inclusion of a finite temperature background <span class="hlt">plasma</span> in the stability analysis results in an ion curvature-driven flute-interchange mode which may be stabilized by either hot-<span class="hlt">electron</span> diamagnetic effects, hot-<span class="hlt">electron</span> <span class="hlt">plasma</span> density, or finite (ion) Larmor radius effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21409508','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21409508"><span id="translatedtitle">Thermal field theory in a layer: Applications of thermal field theory methods to the propagation of photons in a two-dimensional <span class="hlt">electron</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Nieves, Jose F.</p> <p>2010-04-01</p> <p>We apply the thermal field theory methods to study the propagation of photons in a <span class="hlt">plasma</span> layer, that is a <span class="hlt">plasma</span> in which the <span class="hlt">electrons</span> are confined to a two-dimensional plane <span class="hlt">sheet</span>. We calculate the photon self-energy and determine the appropriate expression for the photon propagator in such a medium, from which the properties of the propagating modes are obtained. The formulas for the photon dispersion relations and polarization vectors are derived explicitly in some detail for some simple cases of the thermal distributions of the charged particle gas, and appropriate formulas that are applicable in more general situations are also given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhPl...22l3510S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhPl...22l3510S"><span id="translatedtitle">Generation of anomalously energetic suprathermal <span class="hlt">electrons</span> by an <span class="hlt">electron</span> beam interacting with a nonuniform <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sydorenko, D.; Kaganovich, I. D.; Chen, L.; Ventzek, P. L. G.</p> <p>2015-12-01</p> <p>Generation of anomalously energetic suprathermal <span class="hlt">electrons</span> was observed in simulation of a high-voltage dc discharge with <span class="hlt">electron</span> emission from the cathode. An <span class="hlt">electron</span> beam produced by the emission interacts with the nonuniform <span class="hlt">plasma</span> in the discharge via a two-stream instability. The energy transfer from the beam to the <span class="hlt">plasma</span> <span class="hlt">electrons</span> is ensured by the <span class="hlt">plasma</span> nonuniformity. The <span class="hlt">electron</span> beam excites <span class="hlt">plasma</span> waves whose wavelength and phase speed gradually decrease towards anode. The waves with short wavelength near the anode accelerate <span class="hlt">plasma</span> bulk <span class="hlt">electrons</span> to suprathermal energies. The sheath near the anode reflects some of the accelerated <span class="hlt">electrons</span> back into the <span class="hlt">plasma</span>. These <span class="hlt">electrons</span> travel through the <span class="hlt">plasma</span>, reflect near the cathode, and enter the accelerating area again but with a higher energy than before. Such particles are accelerated to energies much higher than after the first acceleration. This mechanism plays a role in explaining earlier experimental observations of energetic suprathermal <span class="hlt">electrons</span> in similar discharges.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005NIMPB.241..854H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005NIMPB.241..854H"><span id="translatedtitle">Non-vacuum <span class="hlt">electron</span> beam welding through a <span class="hlt">plasma</span> window</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hershcovitch, Ady</p> <p>2005-12-01</p> <p>The <span class="hlt">plasma</span> window is a novel apparatus that utilizes a stabilized <span class="hlt">plasma</span> arc as interface between vacuum and atmosphere or pressurized targets without solid material. Additionally, the <span class="hlt">plasma</span> has a lensing effect on charged particles. This feature enables beam focusing to very small spot sizes and overcoming beam dispersion due to scattering by atmospheric atoms and molecules. Recently, the <span class="hlt">plasma</span> window was mated to a conventional <span class="hlt">electron</span> beam welder. And, <span class="hlt">electron</span> beam welding in atmosphere was accomplished with <span class="hlt">electron</span> beams of unprecedented low power and energy. Weld quality for the non-vacuum <span class="hlt">plasma</span> window <span class="hlt">electron</span> beam welding approached the quality of in-vacuum <span class="hlt">electron</span> beam welding. Indications exist that <span class="hlt">electron</span> beam attenuation is lower than theoretically predicted. Results suggest that air boring was achieved with 6-15 mA, 90-150 keV <span class="hlt">electron</span> beams compared to the previously used kA, MeV <span class="hlt">electron</span> beams. It may explain the better than expected welding results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19810025909&hterms=Planck+Max&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3D%2528Planck%2BMax%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19810025909&hterms=Planck+Max&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3D%2528Planck%2BMax%2529"><span id="translatedtitle">Observations of a nonthermal ion layer at the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary during substorm recovery</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Moebius, E.; Scholer, M.; Hovestadt, D.; Klecker, B.; Ipavich, F. M.; Gloeckler, G.</p> <p>1980-01-01</p> <p>Measurements of the energy and angular distributions of energetic protons and alpha particles (not less than 30 keV/charge) in the geomagnetic tail are presented. The measurements were made during the recovery phase of a geomagnetic substorm on Apr. 19, 1978, with the Max-Planck-Institut/University of Maryland sensor system on the Isee 1 satellite. The measurements were also correlated with <span class="hlt">plasma</span> observations made by the LASL/MPE instrument on Isee 1. The data reveal the presence of a thin nonthermal layer of protons and alpha particles at the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary. The particles have their maximum flux at 60 keV/charge and are streaming highly collimated in the earthward direction. The alpha particle layer is confined within the proton layer. Many aspects of the observations are in agreement with an acceleration model near the neutral line proposed by Jaeger and Speiser (1974)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhPl...22j2116A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhPl...22j2116A"><span id="translatedtitle">An exact collisionless equilibrium for the Force-Free Harris <span class="hlt">Sheet</span> with low <span class="hlt">plasma</span> beta</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Allanson, O.; Neukirch, T.; Wilson, F.; Troscheit, S.</p> <p>2015-10-01</p> <p>We present a first discussion and analysis of the physical properties of a new exact collisionless equilibrium for a one-dimensional nonlinear force-free magnetic field, namely, the force-free Harris <span class="hlt">sheet</span>. The solution allows any value of the <span class="hlt">plasma</span> beta, and crucially below unity, which previous nonlinear force-free collisionless equilibria could not. The distribution function involves infinite series of Hermite polynomials in the canonical momenta, of which the important mathematical properties of convergence and non-negativity have recently been proven. Plots of the distribution function are presented for the <span class="hlt">plasma</span> beta modestly below unity, and we compare the shape of the distribution function in two of the velocity directions to a Maxwellian distribution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPhCS.669a2055S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPhCS.669a2055S"><span id="translatedtitle">Fractal structure of low-temperature <span class="hlt">plasma</span> of arc discharge as a consequence of the interaction of current <span class="hlt">sheets</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smolanov, N. A.</p> <p>2016-01-01</p> <p>The structure of the particles deposited from the <span class="hlt">plasma</span> arc discharge were studied. The flow of <span class="hlt">plasma</span> spreading from the cathode spot to the walls of the vacuum chamber. Electric and magnetic fields to influence the <span class="hlt">plasma</span> flow. The fractal nature of the particles from the <span class="hlt">plasma</span> identified by small-angle X-ray scattering. Possible cause of their formation is due to the instability of the growth front and nonequilibrium conditions for their production - a high speed transition of the vapor-liquid-solid or vapor - crystal. The hypothesis of a <span class="hlt">plasma</span> arc containing dust particles current <span class="hlt">sheets</span> was proposed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22300126','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22300126"><span id="translatedtitle">High and low frequency instabilities driven by counter-streaming <span class="hlt">electron</span> beams in space <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mbuli, L. N.; Maharaj, S. K.; Bharuthram, R.</p> <p>2014-05-15</p> <p>A four-component <span class="hlt">plasma</span> composed of a drifting (parallel to ambient magnetic field) population of warm <span class="hlt">electrons</span>, drifting (anti-parallel to ambient magnetic field) cool <span class="hlt">electrons</span>, stationary hot <span class="hlt">electrons</span>, and thermal ions is studied in an attempt to further our understanding of the excitation mechanisms of broadband electrostatic noise (BEN) in the Earth's magnetospheric regions such as the magnetosheath, plasmasphere, and <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer (PSBL). Using kinetic theory, beam-driven electrostatic instabilities such as the ion-acoustic, <span class="hlt">electron</span>-acoustic instabilities are found to be supported in our multi-component model. The dependence of the instability growth rates and real frequencies on various <span class="hlt">plasma</span> parameters such as beam speed, number density, temperature, and temperature anisotropy of the counter-streaming (relative to ambient magnetic field) cool <span class="hlt">electron</span> beam are investigated. It is found that the number density of the anti-field aligned cool <span class="hlt">electron</span> beam and drift speed play a central role in determining which instability is excited. Using <span class="hlt">plasma</span> parameters which are closely correlated with the measurements made by the Cluster satellites in the PSBL region, we find that the <span class="hlt">electron</span>-acoustic and ion-acoustic instabilities could account for the generation of BEN in this region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920042037&hterms=kay&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dkay','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920042037&hterms=kay&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dkay"><span id="translatedtitle">Measuring ionospheric <span class="hlt">electron</span> density using the <span class="hlt">plasma</span> frequency probe</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jensen, Mark D.; Baker, Kay D.</p> <p>1992-01-01</p> <p>During the past decade, the <span class="hlt">plasma</span> frequency probe (PFP) has evolved into an accurate, proven method of measuring <span class="hlt">electron</span> density in the ionosphere above about 90 km. The instrument uses an electrically short antenna mounted on a sounding rocket that is immersed in the <span class="hlt">plasma</span> and notes the frequency where the antenna impedance is large and nonreactive. This frequency is closely related to the <span class="hlt">plasma</span> frequency, which is a direct function of free <span class="hlt">electron</span> concentration. The probe uses phase-locked loop technology to follow a changing <span class="hlt">electron</span> density. Several sections of the <span class="hlt">plasma</span> frequency probe circuitry are unique, especially the voltage-controlled oscillator that uses both an <span class="hlt">electronically</span> tuned capacitor and inductor to give the wide tuning range needed for <span class="hlt">electron</span> density measurements. The results from two recent sounding rocket flights (Thunderstorm II and CRIT II) under vastly different <span class="hlt">plasma</span> conditions demonstrate the capabilities of the PFP and show the importance of in situ <span class="hlt">electron</span> density measurements of understanding <span class="hlt">plasma</span> processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21560006','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21560006"><span id="translatedtitle">Nonlinear interaction of quantum <span class="hlt">electron</span> <span class="hlt">plasma</span> waves with quantum <span class="hlt">electron</span> acoustic waves in <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chakrabarti, Nikhil; Mylavarapu, Janaki Sita; Dutta, Manjistha; Khan, Manoranjan</p> <p>2011-01-15</p> <p>An analysis of the interaction between modes involving two species with different pressures in the presence of a static-neutralizing ion background is presented using a quantum hydrodynamic model. It is shown that quantum <span class="hlt">electron</span> <span class="hlt">plasma</span> waves can nonlinearly interact with quantum <span class="hlt">electron</span> acoustic waves in a time scale much longer than <span class="hlt">electron</span> <span class="hlt">plasma</span> oscillation response time. A set of coupled nonlinear differential equations is obtained that is similar to the Zakharov equations but includes quantum correction terms. These equations are solved in a moving frame, showing that solitary-wave-like solutions may also be possible in quantum Zakharov equations. It is also shown that quantum effects can reduce the growth rate of the usual caviton instability. Possible applications of the theory are also outlined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EP%26S...67..168C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EP%26S...67..168C"><span id="translatedtitle">Relationship between wave-like auroral arcs and Pi2 disturbances in <span class="hlt">plasma</span> <span class="hlt">sheet</span> prior to substorm onset</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chang, Tzu-Fang; Cheng, Chio-Zong</p> <p>2015-12-01</p> <p>Wave-like substorm arc features in the aurora and Pi2 magnetic disturbances observed in the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> are frequently, and sometimes simultaneously, observed around the substorm onset time. We perform statistical analyses of the THEMIS ASI auroral observations that show wave-like bright spot structure along the arc prior to substorm onset. The azimuthal mode number values of the wave-like substorm arcs are found to be in the range of ~100-240 and decrease with increasing geomagnetic latitude of the substorm auroral arc location. We suggest that the azimuthal mode number is likely related to the ion gyroradius and azimuthal wave number. We also perform correlation study of the pre-onset wave-like substorm arc features and Pi2 magnetic disturbances for substorm dipolarization events observed by THEMIS satellites during 2008-2009. The wave-like arc brightness structures on the substorm auroral arcs tend to move azimuthally westward, but with a few exceptions of eastward movement, during tens of seconds prior to the substorm onset. The movement of the wave-like arc brightness structure is linearly correlated with the phase velocity of the Pi2 ? B y disturbances in the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> region. The result suggests that the Pi2 transverse ? B y disturbances are related to the intensifying wave-like substorm onset arcs. One plausible explanation of the observations is the kinetic ballooning instability, which has high azimuthal mode number due to the ion gyroradius effect and finite parallel electric field that accelerates <span class="hlt">electrons</span> into the ionosphere to produce the wave-like arc structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22408085','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22408085"><span id="translatedtitle"><span class="hlt">Electron</span> <span class="hlt">plasma</span> dynamics during autoresonant excitation of the diocotron mode</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Baker, C. J. Danielson, J. R. Hurst, N. C. Surko, C. M.</p> <p>2015-02-15</p> <p>Chirped-frequency autoresonant excitation of the diocotron mode is used to move <span class="hlt">electron</span> <span class="hlt">plasmas</span> confined in a Penning-Malmberg trap across the magnetic field for advanced <span class="hlt">plasma</span> and antimatter applications. <span class="hlt">Plasmas</span> of 10{sup 8} <span class="hlt">electrons</span>, with radii small compared to that of the confining electrodes, can be moved from the magnetic axis to ?90% of the electrode radius with near unit efficiency and reliable angular positioning. Translations of ?70% of the wall radius are possible for a wider range of <span class="hlt">plasma</span> parameters. Details of this process, including phase and displacement oscillations in the <span class="hlt">plasma</span> response and <span class="hlt">plasma</span> expansion, are discussed, as well as possible extensions of the technique.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26465570','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26465570"><span id="translatedtitle"><span class="hlt">Electron</span> energy distribution in a dusty <span class="hlt">plasma</span>: Analytical approach.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Denysenko, I B; Kersten, H; Azarenkov, N A</p> <p>2015-09-01</p> <p>Analytical expressions describing the <span class="hlt">electron</span> energy distribution function (EEDF) in a dusty <span class="hlt">plasma</span> are obtained from the homogeneous Boltzmann equation for <span class="hlt">electrons</span>. The expressions are derived neglecting <span class="hlt">electron-electron</span> collisions, as well as transformation of high-energy <span class="hlt">electrons</span> into low-energy <span class="hlt">electrons</span> at inelastic <span class="hlt">electron</span>-atom collisions. At large <span class="hlt">electron</span> energies, the quasiclassical approach for calculation of the EEDF is applied. For the moderate energies, we account for inelastic <span class="hlt">electron</span>-atom collisions in the dust-free case and both inelastic <span class="hlt">electron</span>-atom and <span class="hlt">electron</span>-dust collisions in the dusty <span class="hlt">plasma</span> case. Using these analytical expressions and the balance equation for dust charging, the <span class="hlt">electron</span> energy distribution function, the effective <span class="hlt">electron</span> temperature, the dust charge, and the dust surface potential are obtained for different dust radii and densities, as well as for different <span class="hlt">electron</span> densities and radio-frequency (rf) field amplitudes and frequencies. The dusty <span class="hlt">plasma</span> parameters are compared with those calculated numerically by a finite-difference method taking into account <span class="hlt">electron-electron</span> collisions and the transformation of high-energy <span class="hlt">electrons</span> at inelastic <span class="hlt">electron</span>-neutral collisions. It is shown that the analytical expressions can be used for calculation of the EEDF and dusty <span class="hlt">plasma</span> parameters at typical experimental conditions, in particular, in the positive column of a direct-current glow discharge and in the case of an rf <span class="hlt">plasma</span> maintained by an electric field with frequency f=13.56MHz. PMID:26465570</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PFR.....2...45S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PFR.....2...45S"><span id="translatedtitle">Long-Lived Pure <span class="hlt">Electron</span> <span class="hlt">Plasma</span> in Ring Trap-1</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saitoh, Haruhiko; Yoshida, Zensho; Morikawa, Junji; Watanabe, Sho; Yano, Yoshihisa; Suzuki, Junko</p> <p></p> <p>The Ring Trap-1 (RT-1) experiment succeeded in producing a long-lived (of the order 102 s), stable, non-neutral (pure <span class="hlt">electron</span>) <span class="hlt">plasma</span>. <span class="hlt">Electrons</span> are confined by a magnetospheric dipole field. To eliminate a loss channel of the <span class="hlt">plasmas</span> caused by support structures, a superconducting coil was magnetically levitated. This coil levitation drastically improved the confinement properties of the <span class="hlt">electron</span> <span class="hlt">plasma</span> compared to previous Prototype-Ring Trap (Proto-RT) experiments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002GeoRL..29.1293S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002GeoRL..29.1293S"><span id="translatedtitle">Association between quiet-time Pi2 pulsations, poleward boundary intensifications, and <span class="hlt">plasma</span> <span class="hlt">sheet</span> particle fluxes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sutcliffe, P. R.; Lyons, L. R.</p> <p>2002-05-01</p> <p>Pi2 pulsations have been observed to occur at low latitudes during extremely quiet conditions. We have found an excellent correlation between an occurrence of such a Pi2 train and high-latitude Pi2 pulsations and bay-like disturbances in ground magnetic field of the type associated with poleward boundary intensifications (PBIs). The Pi2s and the PBIs that are inferred to occur simultaneously, show a ~30 min repetition rate. They also exhibit an excellent correlation with energetic particle enhancements in the near Earth tail <span class="hlt">plasma</span> <span class="hlt">sheet</span>. These associations demonstrate the large-scale nature of the magnetosphere-ionosphere disturbance that gives rise to PBIs and shows that the disturbance may have important effects on energetic <span class="hlt">plasma</span> <span class="hlt">sheet</span> particles. They show for the first time that PBIs are associated with clearly observable Pi2 pulsations at low latitudes. Our observations are consistent with the possibility that PBIs are part of a large-scale magnetospheric oscillation with ~30 min period.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005JGRA..110.2208E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005JGRA..110.2208E"><span id="translatedtitle">Nonlinear impact of <span class="hlt">plasma</span> <span class="hlt">sheet</span> density on the storm-time ring current</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ebihara, Y.; Fok, M.-C.; Wolf, R. A.; Thomsen, M. F.; Moore, T. E.</p> <p>2005-02-01</p> <p>We investigated the nonlinear impact of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> density on the total energy of the storm-time ring current by means of a numerical simulation that self-consistently solves the kinetic equation of ring current protons and the closure of the electric current between the magnetosphere and ionosphere. Results of the simulation indicate that when the convection electric field is self-consistently coupled with the ring current, the total energy of the ring current ions trapped by the Earth's magnetic field is roughly proportional to Nps1/2, where Nps is the <span class="hlt">plasma</span> <span class="hlt">sheet</span> density. This nonlinear response results from the strengthened shielding electric field with increasing Nps. The total energy is almost proportional to Nps when using an empirical convection electric field, which is independent of the condition of the simulated ring current. An empirical relationship between Nps and the solar wind density was used to estimate time-dependent Nps. The result shows that the calculated Dst* tends to overshoot the observed one when the non-self-consistent electric field is employed. A better agreement was obtained with the self-consistent electric field. We suggest that the nonlinear response of the ring current to Nps is one of the mechanisms that impedes the growth of the storm-time ring current. Another mechanism is probably the saturation of the polar cap potential drop for high solar wind electric field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20110011013&hterms=statistics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dstatistics','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20110011013&hterms=statistics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dstatistics"><span id="translatedtitle">Multiscale Auroral Emission Statistics as Evidence of Turbulent Reconnection in Earth's Midtail <span class="hlt">Plasma</span> <span class="hlt">Sheet</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Klimas, Alex; Uritsky, Vadim; Donovan, Eric</p> <p>2010-01-01</p> <p>We provide indirect evidence for turbulent reconnection in Earth's midtail <span class="hlt">plasma</span> <span class="hlt">sheet</span> by reexamining the statistical properties of bright, nightside auroral emission events as observed by the UVI experiment on the Polar spacecraft and discussed previously by Uritsky et al. The events are divided into two groups: (1) those that map to absolute value of (X(sub GSM)) < 12 R(sub E) in the magnetotail and do not show scale-free statistics and (2) those that map to absolute value of (X(sub GSM)) > 12 R(sub E) and do show scale-free statistics. The absolute value of (X(sub GSM)) dependence is shown to most effectively organize the events into these two groups. Power law exponents obtained for group 2 are shown to validate the conclusions of Uritsky et al. concerning the existence of critical dynamics in the auroral emissions. It is suggested that the auroral dynamics is a reflection of a critical state in the magnetotail that is based on the dynamics of turbulent reconnection in the midtail <span class="hlt">plasma</span> <span class="hlt">sheet</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006CaJPh..84.1029D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006CaJPh..84.1029D"><span id="translatedtitle">Nonlinear stability of the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> during substorms: 9 February 1995 event</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dobias, P.; Wanliss, J. A.; Samson, J. C.</p> <p>2006-12-01</p> <p>It has been previously demonstrated that several minutes prior to an onset of a magnetospheric substorm the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> becomes unstable to resonance-type perturbations. The next logical step, examined here, is an assumption that the velocity shear in the resonance would lead to a development of a Kelvin-Helmholtz (KH) instability. Using a Grad-Shafranov equilibrium constrained by CANOPUS data, we analyze the stability properties of the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> in the presence of a field-line resonance-generated KH instability at around 10 Earth radii. The results of the analysis are in general agreement with observations and computer modeling of substorms. As a part of the analysis, we discuss the importance of the proper distinction between the stability properties of the magnetotail, and the trigger mechanism responsible for the instability. While these two aspects of a substorm may be (and likely are) related, it is possible that they involve different types of processes that work in a complementary fashion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22304210','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22304210"><span id="translatedtitle">Effects of emitted <span class="hlt">electron</span> temperature on the <span class="hlt">plasma</span> sheath</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sheehan, J. P.; Kaganovich, I. D.; Wang, H.; Raitses, Y.; Sydorenko, D.; Hershkowitz, N.</p> <p>2014-06-15</p> <p>It has long been known that <span class="hlt">electron</span> emission from a surface significantly affects the sheath surrounding that surface. Typical fluid theory of a planar sheath with emitted <span class="hlt">electrons</span> assumes that the <span class="hlt">plasma</span> <span class="hlt">electrons</span> follow the Boltzmann relation and the emitted <span class="hlt">electrons</span> are emitted with zero energy and predicts a potential drop of 1.03T{sub e}/e across the sheath in the floating condition. By considering the modified velocity distribution function caused by <span class="hlt">plasma</span> <span class="hlt">electrons</span> lost to the wall and the half-Maxwellian distribution of the emitted <span class="hlt">electrons</span>, it is shown that ratio of <span class="hlt">plasma</span> <span class="hlt">electron</span> temperature to emitted <span class="hlt">electron</span> temperature significantly affects the sheath potential when the <span class="hlt">plasma</span> <span class="hlt">electron</span> temperature is within an order of magnitude of the emitted <span class="hlt">electron</span> temperature. When the <span class="hlt">plasma</span> <span class="hlt">electron</span> temperature equals the emitted <span class="hlt">electron</span> temperature the emissive sheath potential goes to zero. One dimensional particle-in-cell simulations corroborate the predictions made by this theory. The effects of the addition of a monoenergetic <span class="hlt">electron</span> beam to the Maxwellian <span class="hlt">plasma</span> <span class="hlt">electrons</span> were explored, showing that the emissive sheath potential is close to the beam energy only when the emitted <span class="hlt">electron</span> flux is less than the beam flux.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910060899&hterms=resistivity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dresistivity','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910060899&hterms=resistivity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dresistivity"><span id="translatedtitle">Forced magnetic reconnection in a <span class="hlt">plasma</span> <span class="hlt">sheet</span> with localized resistivity profile excited by lower hybrid drift type instability</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hoshino, M.</p> <p>1991-01-01</p> <p>A forced magnetic reconnection process with a temporal evolution of resistivity is studied for a <span class="hlt">plasma</span> <span class="hlt">sheet</span> with a nonuniform resistivity profile based on the nonlocal mode structure of the lower hybrid drift type instability. The growth rate of the mode found is almost independent of the resistivity at the neutral <span class="hlt">sheet</span>, but depends on the resistivity of the region of maximum density gradient away from the neutral <span class="hlt">sheet</span>. This is studied by using both a nonlinear numerical MHD simulation and a linear theory. The mode may be relevant to the prevalent theoretical concept of MHD reconnection and the localized anomalous resistivity profile based on the lower hybrid drift instability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26573995','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26573995"><span id="translatedtitle">Stability of two-dimensional PN monolayer <span class="hlt">sheets</span> and their <span class="hlt">electronic</span> properties.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ma, ShuangYing; He, Chaoyu; Sun, L Z; Lin, Haiping; Li, Youyong; Zhang, K W</p> <p>2015-11-25</p> <p>Three two-dimensional phosphorus nitride (PN) monolayer <span class="hlt">sheets</span> (named as ?-, ?-, and ?-PN, respectively) with fantastic structures and properties are predicted based on first-principles calculations. The ?-PN and ?-PN have a buckled structure, whereas ?-PN shows puckered characteristics. Their unique structures endow these atomic PN <span class="hlt">sheets</span> with high dynamic stabilities and anisotropic mechanical properties. They are all indirect semiconductors and their band gap sensitively depends on the in-plane strain. Moreover, the nanoribbons patterned from these three PN monolayers demonstrate a remarkable quantum size effect. In particular, the zigzag ?-PN nanoribbon shows size-dependent ferromagnetism. Their significant properties show potential in nano-<span class="hlt">electronics</span>. The synthesis of the three phases of the PN monolayer <span class="hlt">sheet</span> is proposed theoretically, which is deserving of further study in experiments. PMID:26573995</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EPJWC..8405004C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EPJWC..8405004C"><span id="translatedtitle"><span class="hlt">Electron</span> collisions with excited molecules in low temperature <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Celiberto, Roberto; Laporta, Vincenzo</p> <p>2015-01-01</p> <p>State-to-state vibrationally resolved cross sections for <span class="hlt">electron</span>-impact processes involving vibrationally excited molecules are reviewed, with particular emphasis on atmospheric and fusion <span class="hlt">plasma</span> applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1233789','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1233789"><span id="translatedtitle">Nonnuclear Nearly Free <span class="hlt">Electron</span> Conduction Channels Induced by Doping Charge in NanotubeMolecular <span class="hlt">Sheet</span> Composites</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhao, Jin; Zheng, Qijing; Petek, Hrvoje; Yang, Jinlong</p> <p>2014-09-04</p> <p>Nearly free <span class="hlt">electron</span> (NFE) states with density maxima in nonnuclear (NN) voids may have remarkable <span class="hlt">electron</span> transport properties ranging from suppressed <span class="hlt">electron</span>phonon interaction to Wigner crystallization. Such NFE states, however, usually exist near the vacuum level, which makes them unsuitable for transport. Through first principles calculations on nanocomposites consisting of carbon nanotube (CNT) arrays sandwiched between boron nitride (BN) <span class="hlt">sheets</span>, we describe a stratagem for stabilizing the NN-NFE states to below the Fermi level. By doping the CNTs with negative charge, we establish Coulomb barriers at CNTs walls that, together with the insulating BN <span class="hlt">sheets</span>, define the transverse potentials of one-dimensional (1D) transport channels, which support the NN-NFE states.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.6258S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.6258S"><span id="translatedtitle">THEMIS two-point measurements of the cross-tail current density: A thick bifurcated current <span class="hlt">sheet</span> in the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saito, Miho</p> <p>2015-08-01</p> <p>The basic properties of the near-Earth current <span class="hlt">sheet</span> from 8 RE to 12 RE were determined based on Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations from 2007 to 2013. Ampere's law was used to estimate the current density when the locations of two spacecraft were suitable for the calculation. A total of 3838 current density observations were obtained to study the vertical profile. For typical solar wind conditions, the current density near (off) the central plane of the current <span class="hlt">sheet</span> ranged from 1 to 2 nA/m2 (1 to 8 nA/m2). All the high current densities appeared off the central plane of the current <span class="hlt">sheet</span>, indicating the formation of a bifurcated current <span class="hlt">sheet</span> structure when the current density increased above 2 nA/m2. The median profile also showed a bifurcated structure, in which the half thickness was about 3 RE. The distance between the peak of the current density and the central plane of the current <span class="hlt">sheet</span> was 0.5 to 1 RE. High current densities above 4 nA/m2 were observed in some cases that occurred preferentially during substorms, but they also occurred in quiet times. In contrast to the commonly accepted picture, these high current densities can form without a high solar wind dynamic pressure. In addition, these high current densities can appear in two magnetic configurations: tail-like and dipolar structures. At least two mechanisms, magnetic flux depletion and new current system formation during the expansion phase, other than <span class="hlt">plasma</span> <span class="hlt">sheet</span> compression are responsible for the formation of the bifurcated current <span class="hlt">sheets</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19990099700&hterms=McCarthy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DMcCarthy%252C%2BR','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19990099700&hterms=McCarthy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DMcCarthy%252C%2BR"><span id="translatedtitle">The Relationship of Ion Beams and Fast Flows in the <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> Boundary Layer</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Parks, G. K.; Reme, H.; Lin, R. P.; Sanderson, T.; Germany, G. A.; Spann, James F., Jr.; Brittnacher, M. J.; McCarthy, M.; Chen, L. J.; Larsen, D.; Phan, T. D.</p> <p>1998-01-01</p> <p>We report new findings on the behavior of <span class="hlt">plasmas</span> in the vicinity of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer (PSBL). A large geometrical factor detector on WIND (3D <span class="hlt">plasma</span> experiment) has discovered a unidirectional ion beam streaming in the tailward direction missed by previous observations. This tailward beam is as intense as the earthward streaming beam and it is found just inside the outer edge of the PSBL where earthward streaming beams are observed. The region where this tailward beam is observed includes an isotropic <span class="hlt">plasma</span> component which is absent in the outer edge where earthward streaming beams are found. When these different distributions are convolved to calculate the velocity moments, fast flows (greater than 400 km/s) result in the earthward direction and much slower flows (less than 200 km/s) in the tailward direction. These new findings are substantially different from previous observations. Thus, the interpretation of fast flows and earthward and counterstreaming ion beams in terms of a neutral line model must be reexamined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002SPIE.4720..105X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002SPIE.4720..105X"><span id="translatedtitle"><span class="hlt">Electron</span>-beam transmission properties in <span class="hlt">plasma</span> channel</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xie, Wenkai; Chen, Xi; Meng, Lin; Gao, Xinyan; Liu, Shenggang</p> <p>2002-06-01</p> <p>In this paper the physical mechanism and mathematical description of magnetically self-focusing <span class="hlt">electron</span> beam are studied.The analysis of <span class="hlt">electron</span> beam with weak pulsation in drifting tube filled with <span class="hlt">plasma</span> was given,the beam with strong pulsation under the same condition was also studied accurately.The results show that whether in (alpha) area or in (beta) area both the range and wave length of beam pulsation related to initial condition and <span class="hlt">plasma</span> parameters although their pulsation properties were different,there exited a optimum <span class="hlt">plasma</span> density when the other condition was set.The experimental studies are also reported of beam transmission in <span class="hlt">plasma</span> channel based on Hollow Cathode <span class="hlt">Plasma</span>(HCP) gun in University of <span class="hlt">Electronic</span> Science and Technology of China(UESTC).The study shows that efficient transmission of <span class="hlt">electron</span> beam in <span class="hlt">plasma</span> channel can be reached by choosing the <span class="hlt">plasma</span> filling factor and voltage.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20636768','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20636768"><span id="translatedtitle">Etching with <span class="hlt">electron</span> beam generated <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Leonhardt, D.; Walton, S.G.; Muratore, C.; Fernsler, R.F.; Meger, R.A.</p> <p>2004-11-01</p> <p>A modulated <span class="hlt">electron</span> beam generated <span class="hlt">plasma</span> has been used to dry etch standard photoresist materials and silicon. Oxygen-argon mixtures were used to etch organic resist material and sulfur hexafluoride mixed with argon or oxygen was used for the silicon etching. Etch rates and anisotropy were determined with respect to gas compositions, incident ion energy (from an applied rf bias) and <span class="hlt">plasma</span> duty factor. For 1818 negative resist and i-line resists the removal rate increased nearly linearly with ion energy (up to 220 nm/min at 100 eV), with reasonable anisotropic pattern transfer above 50 eV. Little change in etch rate was seen as gas composition went from pure oxygen to 70% argon, implying the resist removal mechanism in this system required the additional energy supplied by the ions. With silicon substrates at room temperature, mixtures of argon and sulfur hexafluoride etched approximately seven times faster (1375 nm/min) than mixtures of oxygen and sulfur hexafluoride ({approx}200 nm/min) with 200 eV ions, the difference is attributed to the passivation of the silicon by involatile silicon oxyfluoride (SiO{sub x}F{sub y}) compounds. At low incident ion energies, the Ar-SF{sub 6} mixtures showed a strong chemical (lateral) etch component before an ion-assisted regime, which started at {approx}75 eV. Etch rates were independent of the 0.5%-50% duty factors studied in this work.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19770005001','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19770005001"><span id="translatedtitle">Observations at the planet Mercury by the <span class="hlt">plasma</span> <span class="hlt">electron</span> experiment, Mariner 10</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ogilvie, K. W.; Scudder, J. D.; Vasyliunas, V. M.; Hartle, R. E.; Siscoe, G. L.</p> <p>1976-01-01</p> <p><span class="hlt">Plasma</span> <span class="hlt">electron</span> observations made onboard Mariner 10 are reported. Three encounters with the planet Mercury show that the planet interacts with the solar wind to form a bow shock and a permanent magnetosphere. The observations provide a determination of the dimensions and properties of the magnetosphere, independently of and in general agreement with magnetometer observations. The magnetosphere of Mercury appears to be similar in shape to that of the Earth but much smaller in relation to the size of the planet. <span class="hlt">Electron</span> populations similar to those found in the Earth's magnetotail, within the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and adjacent regions, were observed at Mercury; both their spatial location and the <span class="hlt">electron</span> energy spectra within them bear qualitative and quantitative resemblance to corresponding observations at the Earth. The magnetosphere of Mercury resembles to a marked degree a reduced version of that of the Earth, with no significant differences of structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740002320','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740002320"><span id="translatedtitle">The 3 DLE instrument on ATS-5. [<span class="hlt">plasma</span> <span class="hlt">electron</span> counter</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Deforest, S. E.</p> <p>1973-01-01</p> <p>The performance and operation of the DLE <span class="hlt">plasma</span> <span class="hlt">electron</span> counter on board the ATS 5 are described. Two methods of data presentation, microfilm line plots and spectrograms, are discussed along with <span class="hlt">plasma</span> dynamics, <span class="hlt">plasma</span> flow velocity, electrostatic charging, and wave-particle interactions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/829968','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/829968"><span id="translatedtitle">Vortices, Reconnection and Turbulence in High <span class="hlt">Electron</span>-Beta <span class="hlt">Plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Stenzel, R. L.</p> <p>2004-08-31</p> <p><span class="hlt">Plasmas</span> in which the kinetic energy exceeds the magnetic energy by a significant factor are common in space and in the laboratory. Such <span class="hlt">plasmas</span> can convect magnetic fields and create null points in whose vicinity first the ions become unmagnetized, then the <span class="hlt">electrons</span>. This project focuses on the detailed study of the transition regime of these <span class="hlt">plasmas</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1127069','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1127069"><span id="translatedtitle">Vortex stabilized <span class="hlt">electron</span> beam compressed fusion grade <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hershcovitch, Ady</p> <p>2014-03-19</p> <p>Most inertial confinement fusion schemes are comprised of highly compressed dense <span class="hlt">plasmas</span>. Those schemes involve short, extremely high power, short pulses of beams (lasers, particles) applied to lower density <span class="hlt">plasmas</span> or solid pellets. An alternative approach could be to shoot an intense <span class="hlt">electron</span> beam through very dense, atmospheric pressure, vortex stabilized <span class="hlt">plasma</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22412986','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22412986"><span id="translatedtitle">Effects of nonthermal <span class="hlt">electrons</span> on <span class="hlt">plasma</span> expansion into vacuum</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bennaceur-Doumaz, D. Bara, D.; Benkhelifa, E.; Djebli, M.</p> <p>2015-01-28</p> <p>The expansion of semi-infinite <span class="hlt">plasma</span> into vacuum is analyzed with a hydrodynamic model for cold ions assuming <span class="hlt">electrons</span> modelled by a kappa-type distribution. Similarly to Mora study of a <span class="hlt">plasma</span> expansion into vacuum [P. Mora, Phys. Rev. Lett. 90, 185002 (2003)], we formulated empirical expressions for the electric field strength, velocity, and position of the ion front in one-dimensional nonrelativistic, collisionless isothermally expanding <span class="hlt">plasma</span>. Analytic expressions for the maximum ion energy and the spectrum of the accelerated ions in the <span class="hlt">plasma</span> were derived and discussed to highlight the <span class="hlt">electron</span> nonthermal effects on enhancing the ion acceleration in <span class="hlt">plasma</span> expansion into vacuum.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24618730','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24618730"><span id="translatedtitle">Heat treatment effect on the <span class="hlt">electronic</span> and magnetic structures of nanographene <span class="hlt">sheets</span> investigated through <span class="hlt">electron</span> spectroscopy and conductance measurements.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Takashiro, Jun-ichi; Kudo, Yasuhiko; Kaneko, Satoshi; Takai, Kazuyuki; Ishii, Takafumi; Kyotani, Takashi; Enoki, Toshiaki; Kiguchi, Manabu</p> <p>2014-04-28</p> <p>The heat treatment effect on the <span class="hlt">electronic</span> and magnetic structures of a disordered network of nanographene <span class="hlt">sheets</span> has been investigated by in situ measurements of X-ray photoemission spectroscopy, near-edge X-ray absorption fine structure (NEXAFS), and electrical conductance, together with temperature-programmed desorption measurements. Oxygen-containing functional groups bonded to nanographene edges in the pristine sample are almost completely decomposed under heat treatment up to 1300-1500 K, resulting in the formation of edges primarily terminated by hydrogen. The removal of the oxygen-containing groups enhances the conductance owing to the decrease in the <span class="hlt">electron</span> transport barriers between nanographene <span class="hlt">sheets</span>. Heat treatment above 1500 K removes also the hydrogen atoms from the edges, promoting the successive fusion of nanographene <span class="hlt">sheets</span> at the expense of edges. The decrease in the ?* peak width in NEXAFS indicates the progress of the fusion reaction, that is, the extension of the ?-conjugation, which agrees with the increase in the orbital susceptibility previously reported. The fusion leads to the formation of local ?/sp(2) bridges between nanographene <span class="hlt">sheets</span> and brings about an insulator-to-metal transition at 1500-1600 K, at which the bridge network becomes infinite. As for the magnetism, the intensity of the edge state peak in NEXAFS, which corresponds to the number of the spin-polarized edge states, decreases above 1500 K, though the effective edge-state spin density per edge state starts decreasing at approximately 200 K lower than the temperature of the edge state peak change. This disagreement indicates the development of antiferromagnetic short range ordering as a precursor of a spin glass state near the insulator-metal transition, at which the random network of inter-nanographene-<span class="hlt">sheet</span> exchange interactions strengthened with the formation of the ?/sp(2) bridges becomes infinite. PMID:24618730</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013IJMPB..2750188L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013IJMPB..2750188L"><span id="translatedtitle">Structural and <span class="hlt">Electronic</span> Evolution from SiC <span class="hlt">Sheet</span> to Silicene</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, G.; Wu, M. S.; Ouyang, C. Y.; Xu, B.</p> <p>2013-10-01</p> <p>The evolution of the structural and <span class="hlt">electronic</span> properties from SiC <span class="hlt">sheet</span> to silicene is studied by using first-principles density functional theory. It is found that the planar configurations of the Si-C monolayer systems are basically kept except for the increase of the buckling of the planar structure when the substitution ratio of Si increases. Band gaps of the Si-C monolayer system decrease gradually when the substitution ratio of Si atoms ranges from 0% to 100%. The energy and type of the band gaps are closely related with the substitution ratio of Si atoms and the Si-C order. Further analysis of density of states reveals the orbital contribution of Si and C atoms near the Fermi level. The discussion of the <span class="hlt">electronic</span> evolution from SiC <span class="hlt">sheet</span> to silicene would widen the application of the Si-C monolayer systems in the optoelectronic field in the future nanotechnology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPlPh..81e9008L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPlPh..81e9008L"><span id="translatedtitle">Solitary waves in asymmetric <span class="hlt">electron</span>-positron-ion <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lu, Ding; Li, Zi-Liang; Xie, Bai-Song</p> <p>2015-10-01</p> <p>> By solving the coupled equations of the electromagnetic field and electrostatic potential, we investigate solitary waves in an asymmetric <span class="hlt">electron</span>-positron <span class="hlt">plasma</span> and/or <span class="hlt">electron</span>-positron-ion <span class="hlt">plasmas</span> with delicate features. It is found that the solutions of the coupled equations can capture multipeak structures of solitary waves in the case of cold <span class="hlt">plasma</span>, which are left out by using the long-wavelength approximation. By considering the effect of ion motion with respect to non-relativistic and ultra-relativistic temperature <span class="hlt">plasmas</span>, we find that the ions' mobility can lead to larger-amplitude solitary waves; especially, this becomes more obvious for a high-temperature <span class="hlt">plasma</span>. The effects of asymmetric temperature between <span class="hlt">electrons</span> and positrons and the ion fraction on the solitary waves are also studied and presented. It is shown that the amplitudes of solitary waves decrease with positron temperature in asymmetric temperature <span class="hlt">electron</span>-positron <span class="hlt">plasmas</span> and decrease also with ion concentration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22025441','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22025441"><span id="translatedtitle">Influence of the renormalization <span class="hlt">plasma</span> screening on the <span class="hlt">electron</span>-atom collision in partially ionized <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hong, Woo-Pyo; Jung, Young-Dae</p> <p>2012-02-13</p> <p>The renormalization <span class="hlt">plasma</span> screening effects on the elastic <span class="hlt">electron</span>-atom collision are investigated in partially ionized dense hydrogen <span class="hlt">plasmas</span> using the eikonal method. It is found that the renormalization <span class="hlt">plasma</span> screening suppresses the eikonal phase shift and cross section for the elastic <span class="hlt">electron</span>-atom collision in partially ionized <span class="hlt">plasmas</span>. It is also found that the renormalization <span class="hlt">plasma</span> screening effect on the elastic <span class="hlt">electron</span>-atom collision process increases with an increasing impact parameter. In addition, it is found that the maximum position of the differential cross section is receded from the center of the atom with an increase of the Debye length.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22163071','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22163071"><span id="translatedtitle">Terahertz rectification by periodic two-dimensional <span class="hlt">electron</span> <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Popov, V. V.; Saratov State University, Saratov 410012 </p> <p>2013-06-24</p> <p>The physics of terahertz rectification by periodic two-dimensional <span class="hlt">electron</span> <span class="hlt">plasma</span> is discussed. Two different effects yielding terahertz rectification are studied: the plasmonic drag and plasmonic ratchet. Ultrahigh responsivity of terahertz rectification by periodic two-dimensional <span class="hlt">electron</span> <span class="hlt">plasma</span> in semiconductor heterostructures and graphene is predicted.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1986ZhPmR..43..268P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1986ZhPmR..43..268P"><span id="translatedtitle">Drift-dissipative excitation of <span class="hlt">electron</span> vortices in a <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Petviashvili, V. I.; Pogutse, I. O.</p> <p>1986-03-01</p> <p>Vortex tubes with a diameter smaller than the ion Larmor radius are generated in an inhomogeneous <span class="hlt">plasma</span> as a result of a dissipation involving <span class="hlt">electrons</span>. The mixing in these vortices may be the primary mechanism for the anomalous <span class="hlt">electron</span> thermal conductivity in a <span class="hlt">plasma</span> with m/M much less than beta much less than 1.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21100123','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21100123"><span id="translatedtitle">Holographic interferometry study of two-fluid properties of the <span class="hlt">plasma</span> in current <span class="hlt">sheets</span> formed in heavy noble gases</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bogdanov, S. Yu.; Dreiden, G. V.; Markov, V. S.; Ostrovskaya, G. V.; Frank, A. G.</p> <p>2007-11-15</p> <p>Two-exposure holographic interferometry was used to study the structure of current <span class="hlt">sheets</span> formed in three-dimensional magnetic configurations with a singular X line in heavy noble gases (Ar, Kr, and Xe). It is found that, in the presence of a longitudinal magnetic field B{sub Z} directed along the X line, <span class="hlt">plasma</span> <span class="hlt">sheets</span> take on an unusual shape: they are titled and asymmetric. Their asymmetry becomes more pronounced as the mass of a <span class="hlt">plasma</span> ion increases-a manifestation of the two-fluid properties of the <span class="hlt">plasma</span>. The observed effects can be attributed to additional forces arising due to the interaction of the longitudinal magnetic field B{sub Z} with Hall currents excited in a plane perpendicular to the X line. A qualitative model describing <span class="hlt">plasma</span> dynamics with allowance for the Hall effect and accounting for most of the experimentally observed effects is proposed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21100122','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21100122"><span id="translatedtitle">Numerical simulations of <span class="hlt">plasma</span> equilibrium in a one-dimensional current <span class="hlt">sheet</span> with a nonzero normal magnetic field component</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mingalev, O. V.; Mingalev, I. V.; Malova, Kh. V.; Zelenyi, L. M.</p> <p>2007-11-15</p> <p>The force balance in a thin collisionless current <span class="hlt">sheet</span> in the Earth's magnetotail with a given constant magnetic field component B{sub z} across the <span class="hlt">sheet</span> is numerically studied for the first time in a self-consistent formulation of the problem. The current <span class="hlt">sheet</span> is produced by oppositely directed <span class="hlt">plasma</span> flows propagating from the periphery of the <span class="hlt">sheet</span> toward the neutral plane. A substantially improved version of a macroparticle numerical model is used that makes it possible to simulate on the order of 10{sup 7} macroparticles even with a personal computer and to calculate equilibrium configurations with a sufficiently low discrete noise level in the first-and second-order moments of the distribution function, which determine the stress tensor elements. Quasisteady configurations were calculated numerically for several sets of <span class="hlt">plasma</span> parameters in some parts of the magnetotail. The force balance in the <span class="hlt">sheet</span> was checked by calculating the longitudinal and transverse pressures as well as the elements of the full stress tensor. The stress tensor in the current <span class="hlt">sheet</span> is found to be nondiagonal and to differ appreciably from the gyrotropic stress tensor in the Chew-Goldberger-Low model, although the Chew-Goldberger-Low theory and numerical calculations yield close results for large distances from the region of reversed magnetic field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFMSM21D..07Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFMSM21D..07Z"><span id="translatedtitle">Auroral Poleward Boundary Intensifications: their two-dimensional structure and the associated dynamics in the <span class="hlt">Plasma</span> <span class="hlt">Sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zesta, E.; Lyons, L.; Donovan, E.; Frey, H. U.; Nagai, T.</p> <p>2002-12-01</p> <p>Auroral poleward boundary intensifications (PBIs) have an auroral signature in ground meridional scanning photometer (MSP) data that appears as an increase in intensity at or near the magnetic separatrix. This increase is often seen to extend equatorward through the ionospheric mapping of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. PBIs are associated with <span class="hlt">plasma</span> <span class="hlt">sheet</span> flow bursts and are thus important to <span class="hlt">plasma</span> <span class="hlt">sheet</span> dynamics. We previously found that equatorward extending PBIs are either north-south (NS) aligned structures or east-west (EW) arcs that mostly propagate equatorward. We further investigate the <span class="hlt">plasma</span> <span class="hlt">sheet</span> dynamic structures associated with these two types of PBIs by combining data from the CANOPUS MSPs, auroral images from the IMAGE spacecraft, and magnetic field and <span class="hlt">plasma</span> data from the Geotail spacecraft. We study a period on January 3, 2001, when a series of PBIs were seen in the MSP data for 2.5 hrs. From simultaneous IMAGE and Geotail data we find that: (a) PBIs correlate well with <span class="hlt">plasma</span> <span class="hlt">sheet</span> fast flows observed within the local time sector of the PBIs. There can be several PBIs over the longitudinal range of fast flows in the tail, (b) multiple PBIs can occur over the whole width of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> or in a more restricted local sector (i.e. only pre-midnight). When PBIs are seen only in a local sector fast flows are seen only in that local sector as well. Where no PBIs are seen no fast flows are seen, (c) most of the observed PBIs were EW arcs that initiated near the poleward boundary and then propagated equatorward. They often tilted and became mostly NS structures as they propagated equatorward and duskward, (d) there is a local time dependence on the type of PBI structure. Most PBIs seem to be narrow structures and primarily aligned with a line that goes through the 02 MLT and 17 MLT sectors. This results in PBIs that are NS structures in the postmidnight sector and EW arcs in the dusk sector. In the premidnight sector (22-00 MLT) PBIs start as EW arcs that then tilt and become primarily NS structures. These results suggest that the same <span class="hlt">plasma</span> <span class="hlt">sheet</span> dynamics produce EW and NS PBI structures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22218489','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22218489"><span id="translatedtitle"><span class="hlt">Electron</span> energy distribution function control in gas discharge <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Godyak, V. A.</p> <p>2013-10-15</p> <p>The formation of the <span class="hlt">electron</span> energy distribution function (EEDF) and <span class="hlt">electron</span> temperature in low temperature gas discharge <span class="hlt">plasmas</span> is analyzed in frames of local and non-local <span class="hlt">electron</span> kinetics. It is shown, that contrary to the local case, typical for <span class="hlt">plasma</span> in uniform electric field, there is the possibility for EEDF modification, at the condition of non-local <span class="hlt">electron</span> kinetics in strongly non-uniform electric fields. Such conditions naturally occur in some self-organized steady state dc and rf discharge <span class="hlt">plasmas</span>, and they suggest the variety of artificial methods for EEDF modification. EEDF modification and <span class="hlt">electron</span> temperature control in non-equilibrium conditions occurring naturally and those stimulated by different kinds of <span class="hlt">plasma</span> disturbances are illustrated with numerous experiments. The necessary conditions for EEDF modification in gas discharge <span class="hlt">plasmas</span> are formulated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhyS...90f8005B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhyS...90f8005B"><span id="translatedtitle">Electromagnetic solitons in degenerate relativistic <span class="hlt">electron</span>-positron <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Berezhiani, V. I.; Shatashvili, N. L.; Tsintsadze, N. L.</p> <p>2015-06-01</p> <p>The existence of soliton-like electromagnetic (EM) distributions in a fully degenerate <span class="hlt">electron</span>-positron <span class="hlt">plasma</span> is studied applying relativistic hydrodynamic and Maxwell equations. For a circularly polarized wave it is found that the soliton solutions exist both in relativistic as well as nonrelativistic degenerate <span class="hlt">plasmas</span>. <span class="hlt">Plasma</span> density in the region of soliton pulse localization is reduced considerably. The possibility of <span class="hlt">plasma</span> cavitation is also shown.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/12006024','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/12006024"><span id="translatedtitle">Three-dimensional particle-in-cell simulations of energetic <span class="hlt">electron</span> generation and transport with relativistic laser pulses in overdense <span class="hlt">plasmas</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sentoku, Y; Mima, K; Sheng, Z M; Kaw, P; Nishihara, K; Nishikawa, K</p> <p>2002-04-01</p> <p>The interaction of relativistic laser light with overdense <span class="hlt">plasmas</span> is studied by three-dimensional particle-in-cell simulations. Generation of layered current <span class="hlt">sheets</span> and quasistatic magnetic fields is observed near the target surface owing to anisotropic laser filamentation and Weibel instabilities. Later these current <span class="hlt">sheets</span> tear into filaments that partially merge with each other to form isolated magnetic channels penetrating into the dense <span class="hlt">plasmas</span>. It is found that fast <span class="hlt">electron</span> energy flow is not only inside the magnetic channels but also it is widely distributed outside the channels. This is possible because of <span class="hlt">electron</span> anomalous diffusion across self-generated magnetic fields. Consequently, the total hot <span class="hlt">electron</span> current exceeds a few hundred kiloamperes and is much larger than the Alfvn current. Hence a considerable amount of energy flows towards the <span class="hlt">plasma</span> core. Significant heating of the bulk <span class="hlt">plasma</span> <span class="hlt">electrons</span> is also observed. PMID:12006024</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19880059303&hterms=Plasma+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DPlasma%2Benergy','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19880059303&hterms=Plasma+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DPlasma%2Benergy"><span id="translatedtitle">Dynamical features of the <span class="hlt">plasma-sheet</span> ion composition, density, and energy</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lennartsson, W.</p> <p>1987-01-01</p> <p>The effects of changes in solar and geomagnetic activity on the major <span class="hlt">plasma-sheet</span> ions are investigated on the basis of a statistical analysis of 1500 h of data obtained at distances 10-23 earth radii and energy/charge ratios 0.1-16 keV/e by the ISEE-1 energetic-ion mass spectrometer. The results are presented in extensive graphs and discussed in detail. It is found that substorm activity is accompanied by a significant decrease in the density of solar-origin H(+) ions, a sharp increase in the energy per nucleon of both H(+) and He(+) ions, and an increase in the density of terrestrial O(+) ions. A factor-of-three increase in the overall O(+) density over the observation period is attributed to an increase in the solar EUV flux.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20861387','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20861387"><span id="translatedtitle">Simulation of <span class="hlt">sheet</span>-shaped lithium beam probe performance for two-dimensional edge <span class="hlt">plasma</span> measurement</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tsuchiya, H.; Morisaki, T.; Komori, A.; Motojima, O.</p> <p>2006-10-15</p> <p>A <span class="hlt">sheet</span>-shaped thermal lithium beam probe has been developed for two-dimensional density measurements in the edge region of the torus <span class="hlt">plasma</span>. A numerical simulation was carried out to confirm the validity of the diagnostics for fast and transient phenomena such as edge localized modes or blobs, etc., where the velocity of blobs is faster than that of the probe beam. It was found in the simulation that the density of the blob itself is reconstructed to be low and unexpected ghosts appear in the reconstructed density profile near the blob, if the conventional reconstruction method is employed. These results invite our attention to the numerical errors in the density reconstruction process. On the other hand, the errors can be corrected by using the simulation results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22412952','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22412952"><span id="translatedtitle">Experimental evidence of warm <span class="hlt">electron</span> populations in magnetron sputtering <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sahu, B. B. Han, Jeon G.; Kim, Hye R.; Ishikawa, K.; Hori, M.</p> <p>2015-01-21</p> <p>This work report on the results obtained using the Langmuir probe (LP) measurements in high-power dc magnetron sputtering discharges. Data show clear evidence of two <span class="hlt">electron</span> components, such as warm and bulk <span class="hlt">electrons</span>, in the sputtering <span class="hlt">plasma</span> in a magnetic trap. We have also used optical emission spectroscopy diagnostic method along with LP to investigate the <span class="hlt">plasma</span> production. Data show that there is a presence of low-frequency oscillations in the 23?MHz range, which are expected to be generated by high-frequency waves. Analysis also suggests that the warm <span class="hlt">electrons</span>, in the <span class="hlt">plasmas</span>, can be formed due to the collisionless Landau damping of the bulk <span class="hlt">electrons</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhPl...20l2113S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhPl...20l2113S"><span id="translatedtitle"><span class="hlt">Plasma</span> response to <span class="hlt">electron</span> energy filter in large volume <span class="hlt">plasma</span> device</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sanyasi, A. K.; Awasthi, L. M.; Mattoo, S. K.; Srivastava, P. K.; Singh, S. K.; Singh, R.; Kaw, P. K.</p> <p>2013-12-01</p> <p>An <span class="hlt">electron</span> energy filter (EEF) is embedded in the Large Volume <span class="hlt">Plasma</span> Device <span class="hlt">plasma</span> for carrying out studies on excitation of <span class="hlt">plasma</span> turbulence by a gradient in <span class="hlt">electron</span> temperature (ETG) described in the paper of Mattoo et al. [S. K. Mattoo et al., Phys. Rev. Lett. 108, 255007 (2012)]. In this paper, we report results on the response of the <span class="hlt">plasma</span> to the EEF. It is shown that inhomogeneity in the magnetic field of the EEF switches on several physical phenomena resulting in <span class="hlt">plasma</span> regions with different characteristics, including a <span class="hlt">plasma</span> region free from energetic <span class="hlt">electrons</span>, suitable for the study of ETG turbulence. Specifically, we report that localized structures of <span class="hlt">plasma</span> density, potential, <span class="hlt">electron</span> temperature, and <span class="hlt">plasma</span> turbulence are excited in the EEF <span class="hlt">plasma</span>. It is shown that structures of <span class="hlt">electron</span> temperature and potential are created due to energy dependence of the <span class="hlt">electron</span> transport in the filter region. On the other hand, although structure of <span class="hlt">plasma</span> density has origin in the particle transport but two distinct steps of the density structure emerge from dominance of collisionality in the source-EEF region and of the Bohm diffusion in the EEF-target region. It is argued and experimental evidence is provided for existence of drift like flute Rayleigh-Taylor in the EEF <span class="hlt">plasma</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22218323','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22218323"><span id="translatedtitle"><span class="hlt">Plasma</span> response to <span class="hlt">electron</span> energy filter in large volume <span class="hlt">plasma</span> device</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sanyasi, A. K.; Awasthi, L. M.; Mattoo, S. K.; Srivastava, P. K.; Singh, S. K.; Singh, R.; Kaw, P. K.</p> <p>2013-12-15</p> <p>An <span class="hlt">electron</span> energy filter (EEF) is embedded in the Large Volume <span class="hlt">Plasma</span> Device <span class="hlt">plasma</span> for carrying out studies on excitation of <span class="hlt">plasma</span> turbulence by a gradient in <span class="hlt">electron</span> temperature (ETG) described in the paper of Mattoo et al. [S. K. Mattoo et al., Phys. Rev. Lett. 108, 255007 (2012)]. In this paper, we report results on the response of the <span class="hlt">plasma</span> to the EEF. It is shown that inhomogeneity in the magnetic field of the EEF switches on several physical phenomena resulting in <span class="hlt">plasma</span> regions with different characteristics, including a <span class="hlt">plasma</span> region free from energetic <span class="hlt">electrons</span>, suitable for the study of ETG turbulence. Specifically, we report that localized structures of <span class="hlt">plasma</span> density, potential, <span class="hlt">electron</span> temperature, and <span class="hlt">plasma</span> turbulence are excited in the EEF <span class="hlt">plasma</span>. It is shown that structures of <span class="hlt">electron</span> temperature and potential are created due to energy dependence of the <span class="hlt">electron</span> transport in the filter region. On the other hand, although structure of <span class="hlt">plasma</span> density has origin in the particle transport but two distinct steps of the density structure emerge from dominance of collisionality in the source-EEF region and of the Bohm diffusion in the EEF-target region. It is argued and experimental evidence is provided for existence of drift like flute Rayleigh-Taylor in the EEF <span class="hlt">plasma</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1986GeoRL..13..648E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1986GeoRL..13..648E"><span id="translatedtitle">ISEE-1 and 2 observations of magnetic flux ropes in the magnetotail - FTE's in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Elphic, R. C.; Russell, C. T.; Cattell, C. A.; Takahasi, K.; Bame, S. J.</p> <p>1986-07-01</p> <p>Magnetic field observations on ISEE-1 and 2 in and near the neutral <span class="hlt">sheet</span> about 20 Re down the near-earth magnetotail reveal the occurrence of structures resembling magnetic flux ropes. Both electric field and fast <span class="hlt">plasma</span> data show that these structures convect across the spacecraft at speeds of 200 - 600 km/s, and that they have scale sizes of roughly 3 5 Re. The rope axis orientation is across the tail, approximately in the -Y GSM direction. Their magnetic structure is strikingly similar to magnetic flux ropes observed in the Venus ionosphere, and to flux transfer events observed at the dayside magnetopause. The total field-aligned current within these ropes may approach a million amps. These structures may arise because of patchy reconnection within the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, or may be tearing islands formed when the <span class="hlt">plasma</span> <span class="hlt">sheet</span> magnetic field has a cross-tail component. <span class="hlt">Plasma</span> <span class="hlt">sheet</span> flux ropes are not a common feature at ISEE orbital altitudes; this suggests that near-earth neutral line formation within ISEE apogee (22 Re) may be equally rare.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JPhCS.365a2051P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JPhCS.365a2051P"><span id="translatedtitle">Comparative simulation studies of <span class="hlt">plasma</span> cathode <span class="hlt">electron</span> (PCE) gun</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prajapati, Jitendra; Pal, U. N.; Kumar, Niraj; Verma, D. K.; Prakash, Ram; Srivastava, V.</p> <p>2012-05-01</p> <p>Pseudospark discharge based <span class="hlt">plasma</span> cathode has capability to provide high current density <span class="hlt">electron</span> beam during discharge process. In this paper an effort has been made to simulate the breakdown processes in the pseudospark discharge based <span class="hlt">plasma</span> cathode <span class="hlt">electron</span> gun. The two-dimensional <span class="hlt">plasma</span> simulation codes VORPAL and OOPIC-Pro have been used and results are compared. The peak discharge current in the <span class="hlt">plasma</span> cathode <span class="hlt">electron</span> gun is found to be dependent on aperture size, hollow cathode dimensions, anode voltage and seed <span class="hlt">electrons</span> energy. The effect of these design parameters on the peak anode current has been analysed by both the codes and results matches well within 10% variation. For the seed <span class="hlt">electron</span> generation an <span class="hlt">electron</span> beam trigger source is used to control the discharge process in the hollow cathode cavity. The time span of trigger source has been varied from 1-100 ns to analyze the effect on the peak anode current.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFMSM42B0605Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFMSM42B0605Z"><span id="translatedtitle">Association of north-south Poleward Boundary Intensifications (PBI) orientation with <span class="hlt">plasma</span> <span class="hlt">sheet</span> flow direction and the IMF</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zesta, E.; Lyons, L.; Donovan, E.; Sigwarth, J. B.; Frey, H. U.; Nagai, T.</p> <p>2003-12-01</p> <p>Auroral poleward boundary intensifications (PBIs) are typically seen both in ground meridional scanning photometers (MSP) and in ground and spacecraft auroral images. They appear as a localized increase in intensity at or near the magnetic separatrix. This increase is often seen to extend equatorward through the ionospheric mapping of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. PBIs are associated with <span class="hlt">plasma</span> <span class="hlt">sheet</span> flow bursts and are thus important for the remote monitoring of <span class="hlt">plasma</span> <span class="hlt">sheet</span> dynamics. From the study of simultaneous IMAGE FUV auroral images and Geotail <span class="hlt">plasma</span> <span class="hlt">sheet</span> data we recently found that: (a) PBIs correlate well with <span class="hlt">plasma</span> <span class="hlt">sheet</span> fast flows observed within the local time sector of the PBIs, and there can be several PBIs over the longitudinal range of fast flows in the tail, and (b) there is a local time dependence on the type of PBI structure. Most PBIs seem to be narrow structures and primarily aligned with a line going from ~02 MLT to ~17 MLT. This results in PBIs that are north-south (NS) structures in the postmidnight sector and east-west (EW) arcs in the dusk sector. In the premidnight sector (22-00 MLT), PBIs start as EW arcs that then tilt and become primarily NS structures. These results suggest that the same <span class="hlt">plasma</span> <span class="hlt">sheet</span> dynamics produce EW and NS PBI structures. We further found for one event that the PBI fast flows have a large Vy component resulting from tail convection during positive IMF By, which offers a possible explanation for the alignment direction of PBIs. We now use a variety of spacecraft and ground data (Polar VIS, IMAGE FUV, and ground all-sky images of the aurora, in-situ data from Geotail, and solar wind data) to investigate the generality of the above conclusions. We identify NS PBIs and investigate whether (a) there is a clear distinction in the orientation of the NS PBIs along the 02-17 MLT, the 22-07 MLT lines, or strictly along the NS meridian, (b) the orientation of the NS PBIs is correlated with the direction of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> convection and thus with the IMF By direction, and (c) the local time dependence of the PBI orientation in our previous study is generally observed during all NS PBI periods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22025419','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22025419"><span id="translatedtitle"><span class="hlt">Electron</span> energy distribution function and <span class="hlt">plasma</span> parameters across magnetic filters</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Aanesland, A.; Bredin, J.; Chabert, P.; Godyak, V.</p> <p>2012-01-23</p> <p>The <span class="hlt">electron</span> energy distribution function (EEDF) is measured across a magnetic filter in inductively coupled <span class="hlt">plasmas</span>. The measured EEDFs are found to be Maxwellian in the elastic energy range with the corresponding <span class="hlt">electron</span> temperature monotonously decreasing along the positive gradient of the magnetic field. At the maximum of the magnetic field, the <span class="hlt">electron</span> temperature reaches its minimum and remains nearly constant in the area of the negative gradient of the field, where the <span class="hlt">plasma</span> density distribution exhibits a local minimum.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000RScI...71..859O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000RScI...71..859O"><span id="translatedtitle">Influence of <span class="hlt">electron</span> injection on <span class="hlt">electron</span> cyclotron resonance <span class="hlt">plasma</span> properties and reflected mode <span class="hlt">electrons</span> (abstract)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ovsyannikov, V. P.; Ullmann, F.; Zschornack, G.</p> <p>2000-02-01</p> <p>The injection of an additional strong focused <span class="hlt">electron</span> beam from a special designed <span class="hlt">electron</span> gun into a magnetic <span class="hlt">electron</span> cyclotron resonance (ECR) confinement field is studied. The <span class="hlt">electron</span> gun uses a cathode with a long lifetime and resistiveness providing high emission current densities with <span class="hlt">electron</span> currents up to 50 mA and voltages up to 4 keV. A sequence of aluminum foils is used to investigate the trajectories of the <span class="hlt">electrons</span> in the magnetic field without <span class="hlt">plasma</span>. The high density <span class="hlt">electron</span> beam passes through the foils, welds them, and prints its image into the foils. Details of this technique are described in Ref. 1. Using this technique we see that before the <span class="hlt">electrons</span> enter the sextupole region the beam moves along the magnetic straight lines preserving its structure. Only a central beam passes through the sextupole region, thereby changing its form due to the interaction with radial components of the magnetic field. A new operation method at our 14.5 GHz ECR ion source is based on so-called reflection mode <span class="hlt">electrons</span> (RMEs) analogous to a known <span class="hlt">electron</span> beam ion source operation regime.2 The basic idea is that <span class="hlt">electrons</span>, which traveling from the cathode in a strong axial field, meet an anticathode potential, are reflected from it, move back to the cathode, and will be reflected again and so on. It can be supposed that the <span class="hlt">electrons</span> will make reflections up to the moment when the anode aperture of the gun is fulfilled and the <span class="hlt">electrons</span> will be collected on the anode electrode. Investigations are performed extracting nitrogen ions using the RME beam. As a result we got a clear increase in the beam current of the extracted ions (e.g., at 10 mA <span class="hlt">electron</span> injection an increase of the current of N5+ ions up to 400%) and a shift of the measured ion charge state distribution to higher mean ionization stages. Measured x-ray spectra from a neon loaded <span class="hlt">plasma</span> show for the case of RME operation increasing energy shifts to the high energy side of the spectra, i.e., the mean ionization degree of the ions in the <span class="hlt">plasma</span> increases. They also increase the intensity of the neon K x rays (more than 100% increase for RME injection of Ee=4 keV and Ie=10 mA) indicating that for the same operation parameters the mean density of energetic <span class="hlt">electrons</span> rises at RME injection, i.e., there are more <span class="hlt">electrons</span> with energies high enough to ionize K-shell <span class="hlt">electrons</span> in neon.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19890063392&hterms=plasma+energy&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dplasma%2Benergy','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19890063392&hterms=plasma+energy&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dplasma%2Benergy"><span id="translatedtitle">Energy loss of fast nonthermal <span class="hlt">electrons</span> in <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kunc, Joseph A.</p> <p>1989-01-01</p> <p>Simple analytical expressions for equilibration times of nonrelativistic monoenergetic <span class="hlt">electrons</span> in <span class="hlt">plasmas</span> are evaluated in the 'weak'-beam approximation when the density of the monoenergetic <span class="hlt">electrons</span> is much smaller than the <span class="hlt">plasma</span> density. The equilibration time is defined as the time needed by the beam of monenergetic <span class="hlt">electrons</span> to lose most of its energy as a result of collisions with <span class="hlt">plasma</span> particles having a Maxwellian energy distribution. The process of energy equilibration is treated as a statistical superposition of both elastic and inelastic collisions in the <span class="hlt">plasma</span>. The possibility of collisionless equilibration is discussed. Comparison of the equilibration times with the Spitzer relaxation times indicates that the former times are more appropriate for an estimate of the energy loss of the 'weak' <span class="hlt">electron</span> beams in highly ionized <span class="hlt">plasmas</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhDT.......212C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhDT.......212C"><span id="translatedtitle">Field Emission Properties of Carbon Nanotube Fibers and <span class="hlt">Sheets</span> for a High Current <span class="hlt">Electron</span> Source</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Christy, Larry</p> <p></p> <p>Field emission (FE) properties of carbon nanotube (CNT) fibers from Rice University and the University of Cambridge have been studied for use within a high current <span class="hlt">electron</span> source for a directed energy weapon. Upon reviewing the performance of these two prevalent CNT fibers, cathodes were designed with CNT fibers from the University of Cincinnati Nanoworld Laboratory. Cathodes composed of a single CNT fiber, an array of three CNT fibers, and a nonwoven CNT <span class="hlt">sheet</span> were investigated for FE properties; the goal was to design a cathode with emission current in excess of 10 mA. Once the design phase was complete, the cathode samples were fabricated, characterized, and then analyzed to determine FE properties. Electrical conductivity of the CNT fibers was characterized with a 4-probe technique. FE characteristics were measured in an ultra-high vacuum chamber at Wright-Patterson Air Force Base. The arrayed CNT fiber and the enhanced nonwoven CNT <span class="hlt">sheet</span> emitter design demonstrated the most promising FE properties. Future work will include further analysis and cathode design using this nonwoven CNT <span class="hlt">sheet</span> material to increase peak current performance during <span class="hlt">electron</span> emission.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22317935','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22317935"><span id="translatedtitle">Novel spin-<span class="hlt">electronic</span> properties of BC{sub 7} <span class="hlt">sheets</span> induced by strain</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Xu, Lei; Dai, ZhenHong Sui, PengFei; Sun, YuMing; Wang, WeiTian</p> <p>2014-11-01</p> <p>Based on first-principles calculations, the authors have investigated the <span class="hlt">electronic</span> and magnetic properties of BC{sub 7} <span class="hlt">sheets</span> with different planar strains. It is found that metalsemiconductor transition appears at the biaxial strain of 15.5%, and the <span class="hlt">sheets</span> are characteristic of spin-polarized semiconductor with a zero band-gap. The band-gap rapidly increases with strain, and reaches a maximum value of 0.60 eV at the strain of 20%. Subsequently, the band-gap decreases until the strain reaches up to 22% and shows a semiconductor-half metal transformation. It will further present metal properties until the strain is up to the maximum value of 35%. The magnetic moments also have some changes induced by biaxial strain. The numerical analysis shows that the two-dimensional distortions have great influences on the magnetic moments. The novel spin-<span class="hlt">electronic</span> properties make BC{sub 7} <span class="hlt">sheets</span> have potential applications in future spintronic nanodevices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ChJOL..30...12W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ChJOL..30...12W"><span id="translatedtitle"><span class="hlt">Electron</span> transfer from sulfate-reducing becteria biofilm promoted by reduced graphene <span class="hlt">sheets</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wan, Yi; Zhang, Dun; Wang, Yi; Wu, Jiajia</p> <p>2012-01-01</p> <p>Reduced graphene <span class="hlt">sheets</span> (RGSs) mediate <span class="hlt">electron</span> transfer between sulfate-reducing bacteria (SRB) and solid electrodes, and promote the development of microbial fuel cells (MFC). We have investigated RSG-promoted <span class="hlt">electron</span> transfer between SRB and a glassy carbon (GC) electrode. The RGSs were produced at high yield by a chemical sequence involving graphite oxidation, ultrasonic exfoliation of nanosheets, and N2H4 reduction. Cyclic voltammetric testing showed that the characteristic anodic peaks (around 0.3 V) might arise from the combination of bacterial membrane surface cytochrome c3 and the metabolic products of SRB. After 6 d, another anodic wave gradually increased to a maximum current peak and a third anodic signal became visible at around 0 V. The enhancements of two characteristic anodic peaks suggest that RSGs mediate <span class="hlt">electron</span>-transfer kinetics between bacteria and the solid electrode. Manipulation of these recently-discovered <span class="hlt">electron</span>-transport mechanisms will lead to significant advances in MFC engineering.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=33123','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=33123"><span id="translatedtitle">Paper-like <span class="hlt">electronic</span> displays: Large-area rubber-stamped plastic <span class="hlt">sheets</span> of <span class="hlt">electronics</span> and microencapsulated electrophoretic inks</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rogers, John A.; Bao, Zhenan; Baldwin, Kirk; Dodabalapur, Ananth; Crone, Brian; Raju, V. R.; Kuck, Valerie; Katz, Howard; Amundson, Karl; Ewing, Jay; Drzaic, Paul</p> <p>2001-01-01</p> <p><span class="hlt">Electronic</span> systems that use rugged lightweight plastics potentially offer attractive characteristics (low-cost processing, mechanical flexibility, large area coverage, etc.) that are not easily achieved with established silicon technologies. This paper summarizes work that demonstrates many of these characteristics in a realistic system: organic active matrix backplane circuits (256 transistors) for large (≈5 × 5-inch) mechanically flexible <span class="hlt">sheets</span> of <span class="hlt">electronic</span> paper, an emerging type of display. The success of this effort relies on new or improved processing techniques and materials for plastic <span class="hlt">electronics</span>, including methods for (i) rubber stamping (microcontact printing) high-resolution (≈1 μm) circuits with low levels of defects and good registration over large areas, (ii) achieving low leakage with thin dielectrics deposited onto surfaces with relief, (iii) constructing high-performance organic transistors with bottom contact geometries, (iv) encapsulating these transistors, (v) depositing, in a repeatable way, organic semiconductors with uniform electrical characteristics over large areas, and (vi) low-temperature (≈100°C) annealing to increase the on/off ratios of the transistors and to improve the uniformity of their characteristics. The sophistication and flexibility of the patterning procedures, high level of integration on plastic substrates, large area coverage, and good performance of the transistors are all important features of this work. We successfully integrate these circuits with microencapsulated electrophoretic “inks” to form <span class="hlt">sheets</span> of <span class="hlt">electronic</span> paper. PMID:11320233</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22253714','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22253714"><span id="translatedtitle">Probing the <span class="hlt">electronic</span> structure of graphene <span class="hlt">sheets</span> with various thicknesses by scanning transmission X-ray microscopy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bai, Lili; Liu, Jinyin; Zhao, Guanqi; Gao, Jing; Sun, Xuhui E-mail: jzhong@suda.edu.cn; Zhong, Jun E-mail: jzhong@suda.edu.cn</p> <p>2013-12-16</p> <p>The <span class="hlt">electronic</span> structure of an aggregation of graphene <span class="hlt">sheets</span> with various thicknesses was probed by scanning transmission X-ray microscopy. A uniform oxidation of the graphene <span class="hlt">sheets</span> in the flat area was observed regardless of the thickness, while in the folded area the result could be strongly affected by the geometry. Moreover, thick parts of the aggregation showed strong angle-dependence to the incident X-ray, while thin parts showed less angle-dependence, which might be related to the surface wrinkles and ripples. The <span class="hlt">electronic</span> structure differences due to the geometry and thickness suggest a complicated situation in the aggregation of graphene <span class="hlt">sheets</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850004205','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850004205"><span id="translatedtitle">Cold streams of ionospheric oxygen in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> during the CDAW-6 event of March 22, 1979</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Orsini, S.; Amata, E.; Candidi, M.; Balsiger, H.; Stokholm, M.; Huang, C. Y.; Lennartsson, W.; Lindqvist, P. A.</p> <p>1983-01-01</p> <p>During magnetospheric substorm events, the <span class="hlt">plasma</span> and ion composition experiments in the ISEE-1 and 2 satellites detected cold ionospheric O+ streams, moving tailwards in the near Earth magnetotail. Flow is parallel to the magnetic field lines, with drift velocity in agreement with the electric field topology obtained by mapping the model ionospheric field along the magnetic field lines. Fluctuations of the flow velocity of the streams can be related to magnetotail movements. Oscillations of the flow direction and speed with periods ranging from 5 to 10 min that suggest the presence of waves are observed. The streams are observed at all distances between 15 and 6 Re from the Earth. When averaged over 360 deg, the streams show up as a low energy peak, superimposed on the distribution of isotropic <span class="hlt">plasma</span> <span class="hlt">sheet</span> ions. This double-peak structure of the energy spectrum seems typical of the disturbed <span class="hlt">plasma</span> <span class="hlt">sheet</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23368060','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23368060"><span id="translatedtitle"><span class="hlt">Electron</span> acoustic shock waves in a collisional <span class="hlt">plasma</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dutta, Manjistha; Ghosh, Samiran; Chakrabarti, Nikhil</p> <p>2012-12-01</p> <p>A nonlinear analysis for the finite amplitude <span class="hlt">electron</span> acoustic wave (EAW) is considered in a collisional <span class="hlt">plasma</span>. The fluid model is used to describe the two-temperature <span class="hlt">electron</span> species in a fixed ion background. In general, in <span class="hlt">electron</span>-ion <span class="hlt">plasma</span>, the presence of wave nonlinearity, dispersion, and dissipation (arising from fluid viscosity) give rise to the Korteweg-de Vries Burgers (KdVB) equation which exhibits shock wave. In this work, it is shown that the dissipation due to the collision between <span class="hlt">electron</span> and ion in the presence of collective phenomena (<span class="hlt">plasma</span> current) can also introduce an anomalous dissipation that causes the Burgers term and thus leads to the generation of <span class="hlt">electron</span> acoustic shock wave. Both analytical and numerical analysis show the formation of transient shock wave. Relevance of the results are discussed in the context of space <span class="hlt">plasma</span>. PMID:23368060</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19820045578&hterms=Debye+huckel&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DDebye%2Bhuckel','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19820045578&hterms=Debye+huckel&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DDebye%2Bhuckel"><span id="translatedtitle">Level shifts and inelastic <span class="hlt">electron</span> scattering in dense <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Davis, J.; Blaha, M.</p> <p>1982-01-01</p> <p>A completely quantum mechanical formalism has been developed to describe the high density <span class="hlt">plasma</span> effects on fundamental atomic parameters. Both the bound and free <span class="hlt">electrons</span> are treated by a method which in principle is similar to Hartree's self-consistent field method. The free <span class="hlt">plasma</span> <span class="hlt">electrons</span>' wavefunction is obtained from the Schroedinger equation with the effective potential representing the spherically averaged Coulomb interaction with bound and free <span class="hlt">electrons</span>. Results are given for level shifts, coefficients of transition probabilities, and <span class="hlt">electron</span> collision cross sections of Ne(9+) for temperatures of 200 and 500 eV for an <span class="hlt">electron</span> density range of 1-6 x 10 to the 24th per cu cm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22252089','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22252089"><span id="translatedtitle">Solitary and shock waves in magnetized <span class="hlt">electron</span>-positron <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lu, Ding; Li, Zi-Liang; Abdukerim, Nuriman; Xie, Bai-Song</p> <p>2014-02-15</p> <p>An Ohm's law for <span class="hlt">electron</span>-positron (EP) <span class="hlt">plasma</span> is obtained. In the framework of EP magnetohydrodynamics, we investigate nonrelativistic nonlinear waves' solutions in a magnetized EP <span class="hlt">plasma</span>. In the collisionless limit, quasistationary propagating solitary wave structures for the magnetic field and the <span class="hlt">plasma</span> density are obtained. It is found that the wave amplitude increases with the Mach number and the Alfvn speed. However, the dependence on the <span class="hlt">plasma</span> temperature is just the opposite. Moreover, for a cold EP <span class="hlt">plasma</span>, the existence range of the solitary waves depends only on the Alfvn speed. For a hot EP <span class="hlt">plasma</span>, the existence range depends on the Alfvn speed as well as the <span class="hlt">plasma</span> temperature. In the presence of collision, the electromagnetic fields and the <span class="hlt">plasma</span> density can appear as oscillatory shock structures because of the dissipation caused by the collisions. As the collision frequency increases, the oscillatory shock structure becomes more and more monotonic.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AIPC.1670c0031S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AIPC.1670c0031S"><span id="translatedtitle">Kinetic Alfven wave in the presence of kappa distribution function in <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shrivastava, G.; Shrivastava, J.; Ahirwar, G.</p> <p>2015-07-01</p> <p>The particle aspect approach is adopted to investigate the trajectories of charged particles in the electromagnetic field of kinetic Alfven wave. Expressions are found for the dispersion relation, damping/growth rate and associated currents in the presence of kappa distribution function. Kinetic effect of <span class="hlt">electrons</span> and ions are included to study kinetic Alfven wave because both are important in the transition region. It is found that the ratio ? of <span class="hlt">electron</span> thermal energy density to magnetic field energy density and the ratio of ion to <span class="hlt">electron</span> thermal temperature (Ti/Te), and kappa distribution function affect the dispersion relation, damping/growth rate and associated currents in both cases(warm and cold <span class="hlt">electron</span> limit).The treatment of kinetic Alfven wave instability is based on assumption that the <span class="hlt">plasma</span> consist of resonant and non resonant particles. The resonant particles participate in an energy exchange process, whereas the non resonant particles support the oscillatory motion of the wave.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5590978','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5590978"><span id="translatedtitle">Potential applications of an <span class="hlt">electron</span> cyclotron resonance multicusp <span class="hlt">plasma</span> source</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tsai, C.C.; Berry, L.A.; Gorbatkin, S.M.; Haselton, H.H.; Roberto, J.B.; Stirling, W.L.</p> <p>1989-01-01</p> <p>An <span class="hlt">electron</span> cyclotron resonance (ECR) multicusp plasmatron has been developed by feeding a multicusp bucket arc chamber with a compact ECR <span class="hlt">plasma</span> source. This novel source produced large (about 25-cm-diam), uniform (to within {plus minus}10%), dense (>10{sup 11}-cm{sup -3}) <span class="hlt">plasmas</span> of argon, helium, hydrogen, and oxygen. It has been operated to produce an oxygen <span class="hlt">plasma</span> for etching 12.7-cm (5-in.) positive photoresist-coated silicon wafers with uniformity within {plus minus}8%. Results and potential applications of this new ECR <span class="hlt">plasma</span> source for <span class="hlt">plasma</span> processing of thin films are discussed. 21 refs., 10 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19720054061&hterms=bhabha&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dbhabha','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19720054061&hterms=bhabha&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dbhabha"><span id="translatedtitle">Energy loss of fast <span class="hlt">electrons</span> and positrons in a <span class="hlt">plasma</span>.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gould, R. J.</p> <p>1972-01-01</p> <p>Calculation of the stopping power of a <span class="hlt">plasma</span> for fast <span class="hlt">electrons</span> and positrons. First the classical limit is considered where beta = v/c is much less than alpha is the fine structure constant. Then the nonrelativistic Born-approximation formulas are derived; this domain corresponds to alpha much less than beta much less than 1. Finally, the general case of relativistic <span class="hlt">electrons</span> and positrons is treated; in the relativistic case the scattering cross sections of Moller (<span class="hlt">electron-electron</span>) and Bhabha (positron-<span class="hlt">electron</span>) are used in the calculation. In all three energy domains the problem is broken up into cases of small and large momentum transfers. For large q, scattering off individual <span class="hlt">plasma</span> <span class="hlt">electrons</span> is considered, while in the limit of very small q for the quantum-mechanical domain, excitation of quantized <span class="hlt">plasma</span> oscillations contributes to dE/dx; in the classical limit for small q the polarizability of the <span class="hlt">plasma</span> provides the effective cutoff. The formulas for the stopping power differ slightly from those for a heavy ion going through a <span class="hlt">plasma</span> because there are exchange effects and the fast <span class="hlt">electrons</span> and positrons can lose a large fraction of their energy in one scattering off a <span class="hlt">plasma</span> <span class="hlt">electron</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..GECMR2001G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..GECMR2001G"><span id="translatedtitle">Detection of solvated <span class="hlt">electrons</span> at a <span class="hlt">plasma</span>-liquid interface</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Go, David B.; Rumbach, Paul; Bartels, David; Sankaran, R. Mohan</p> <p>2014-10-01</p> <p>We have recently shown that charge can be transferred from a DC microplasma jet into an aqueous solution to promote electrolytic reduction reactions [1,2]. However, the precise nature of these charge transfer reactions remains poorly understood---in particular, it is not known if <span class="hlt">plasma</span> <span class="hlt">electrons</span> solvate and solvated <span class="hlt">electrons</span> are responsible for the reduction of solution species. To address these questions, we have designed and built an optical absorption spectroscopy system to directly detect solvated <span class="hlt">electrons</span> at a <span class="hlt">plasma</span>-liquid interface, which only have a lifetime of ~1 ?s. Our preliminary results reveal that <span class="hlt">plasma</span> <span class="hlt">electrons</span> do indeed solvate, and survive up to depths of approximately 0.5 nm beneath the <span class="hlt">plasma</span>-liquid interface. Adding <span class="hlt">electron</span> scavengers such as nitrite and nitrate salts to the solution causes a decrease in optical absorption, indicating a decrease in the average lifetime of the solvated <span class="hlt">electrons</span>, further confirming their existence. Measuring optical absorption as a function of scavenger concentration, we extrapolate rate constants that agree well with prior radiolysis experiments. These preliminary findings are consistent with the hypothesis that free <span class="hlt">electrons</span> from atmospheric pressure <span class="hlt">plasmas</span> solvate in aqueous solutions, and open potential applications of <span class="hlt">plasmas</span> for solvated <span class="hlt">electron</span> chemistry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21016275','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21016275"><span id="translatedtitle"><span class="hlt">Electron</span> <span class="hlt">plasma</span> wave propagation in external-electrode fluorescent lamps</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cho, Guangsup; Kim, Jung-Hyun; Jeong, Jong-Mun; Hong, Byoung-Hee; Koo, Je-Huan; Choi, Eun-Ha; Verboncoeur, John P.; Uhm, Han Sup</p> <p>2008-01-14</p> <p>The optical propagation observed along the positive column of external electrode fluorescent lamps is shown to be an <span class="hlt">electron</span> <span class="hlt">plasma</span> wave propagating with the <span class="hlt">electron</span> thermal speed of (kT{sub e}/m){sup 1/2}. When the luminance of the lamp is 10 000-20 000 cd/m{sup 2}, the <span class="hlt">electron</span> <span class="hlt">plasma</span> temperature and the <span class="hlt">plasma</span> density in the positive column are determined to be kT{sub e}{approx}1.26-2.12 eV and n{sub o}{approx}(1.28-1.69)x10{sup 17} m{sup -3}, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007PhDT........36G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007PhDT........36G"><span id="translatedtitle">Expansion and <span class="hlt">electron</span> temperature evolution in an ultracold neutral <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gupta, Priya</p> <p></p> <p>This work describes the evolution of an ultracold neutral <span class="hlt">plasma</span> as it expands freely in vacuum. It presents a comprehensive study of the <span class="hlt">electron</span> temperature evolution under different initial conditions. Ultracold neutral <span class="hlt">plasmas</span> are created by photoionizing laser-cooled neutral atoms in ultrahigh vacuum. The ions are typically at a temperature of 1K while the <span class="hlt">electron</span> temperature can be set from 1--1000 K. After photoionization, some of the highly energetic <span class="hlt">electrons</span> escape from the cloud, leaving a net positive charge in the cloud. This creates a Coulomb well which traps the rest of the <span class="hlt">electrons</span>, and a <span class="hlt">plasma</span> is formed. Since the <span class="hlt">electrons</span> have a lot of kinetic energy, they tend to leave the cloud, however, the Coulomb force from the ion pulls the <span class="hlt">electrons</span> back into the cloud. This exerts a recoil force on the ions, and the whole <span class="hlt">plasma</span> starts expanding radially outwards. Since the expansion is caused by the thermal pressure of the <span class="hlt">electrons</span>, a study of the <span class="hlt">plasma</span> expansion unravels the complicated <span class="hlt">electron</span> temperature evolution, under different initial conditions. Many collisional processes become significant as a <span class="hlt">plasma</span> expands. These physical processes tend to heat or cool the ions and <span class="hlt">electrons</span>, leading to very different kinds of evolution depending on the initial conditions of the <span class="hlt">plasma</span>. This work demonstrates three different regions of parameter space where the degree of significance of these physical processes is different during the ultracold neutral <span class="hlt">plasma</span> evolution. The experimental results are verified by theoretical simulations, performed by Thomas Pohl, which untangle the complicated <span class="hlt">electron</span> temperature evolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750022918','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750022918"><span id="translatedtitle"><span class="hlt">Electron</span> <span class="hlt">plasma</span> oscillations associated with type 3 radio emissions and solar <span class="hlt">electrons</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gurnett, D. A.; Frank, L. A.</p> <p>1975-01-01</p> <p>An extensive study of the IMP-6 and IMP-8 <span class="hlt">plasma</span> and radio wave data was performed to try to find <span class="hlt">electron</span> <span class="hlt">plasma</span> oscillations associated with type III radio noise bursts and low-energy solar <span class="hlt">electrons</span>. It is shown that <span class="hlt">electron</span> <span class="hlt">plasma</span> oscillations are seldom observed in association with solar <span class="hlt">electron</span> events and type III radio bursts at 1.0 AU. For the one case in which <span class="hlt">electron</span> <span class="hlt">plasma</span> oscillations are definitely produced by the <span class="hlt">electrons</span> ejected by the solar flare the electric field strength is relatively small. Electromagnetic radiation, believed to be similar to the type III radio emission, is observed coming from the region of the more intense <span class="hlt">electron</span> <span class="hlt">plasma</span> oscillations upstream. Quantitative calculations of the rate of conversion of the <span class="hlt">plasma</span> oscillation energy to electromagnetic radiation are presented for <span class="hlt">plasma</span> oscillations excited by both solar <span class="hlt">electrons</span> and <span class="hlt">electrons</span> from the bow shock. These calculations show that neither the type III radio emissions nor the radiation from upstream of the bow shock can be adequately explained by a current theory for the coupling of <span class="hlt">electron</span> <span class="hlt">plasma</span> oscillations to electromagnetic radiation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E1539K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E1539K"><span id="translatedtitle">Self-consistent theory of the multiscale and split current <span class="hlt">sheets</span> in collisionless non-Maxwellian <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kocharovsky, Vladimir; Martyanov, Vladimir; Kocharovsky, Vitaly</p> <p></p> <p>In view of a large number of the observational and theoretical indications of the complicated non-Maxwellian <span class="hlt">plasma</span> configurations in the magnetospheres of planets and stars, we develop an analytical approach to the description of the stationary planar neutral current <span class="hlt">sheets</span> in a collisionless multicomponent <span class="hlt">plasma</span>, relativistic or not. It is based on the method of the invariants of particle motion and admits a functional freedom in the choice of the particle distribution functions and spatial profiles of current density and corresponding magnetic field. Using a general theory (Phys. Rev. Lett. 104, 215002 (2010)) and a variety of novel examples, we show that splitting of the current <span class="hlt">sheets</span> is typical for the non-Maxwellian distributions of particles and the multiscale current <span class="hlt">sheets</span> might exist in <span class="hlt">plasma</span> with essentially different anisotropies of the particle species. The examples of splitting include the self-consistent <span class="hlt">sheets</span> with two or three separate components of current density with either parallel or antiparallel directions of the current which may be formed by one or several particle species. The examples of the multiscale <span class="hlt">sheets</span> include two or three current components, embedded in one another and formed by one, two or three particle species. We describe general properties of the split and multiscale <span class="hlt">sheets</span> for a wide class of the particle distribution functions with the polynomial and/or exponential dependences on a momentum directed along the current. We investigate in detail possible interrelation of the spatial scales and magnitudes of the magnetic field, anisotropy, and density of particles of different species. In particular, we apply these results to the description of the current structures in the Earths magnetotail using observational data from the Cluster spacecraft mission. We compare our analytical results with the known numerical analysis and qualitative estimates of multiscale properties and splitting effects in the magnetospheric current structures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1989SPIE.1061..273B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1989SPIE.1061..273B"><span id="translatedtitle">Proof-of-principle experiment for a <span class="hlt">sheet</span>-beam, near-millimeter, free <span class="hlt">electron</span> laser with output power up to 1 megawatt</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Booske, J. H.; Antonsen, T. M., Jr.; Carmel, Y.; Destler, W. W.; Finn, J.</p> <p>1989-07-01</p> <p>The use of a small-period (less than 1 cm) wiggler together with a <span class="hlt">sheet</span> <span class="hlt">electron</span> beam has been proposed as a low-cost source of power for <span class="hlt">electron</span> cyclotron resonance heating in magnetic fusion <span class="hlt">plasmas</span> and for space-based radar systems. Stable propagation of a <span class="hlt">sheet</span> beam (18 A, 1 mm x 20 mm) has been demonstrated through a 10-period wiggler electromagnet with peak field of 1.2 kG. Calculation of microwave wall heating and pressurized water cooling have also been carried out, and the feasibility of operating a near-mm <span class="hlt">sheet</span>-beam FEL with an output power of 1 MW CW is indicated. Based on these encouraging results, a proof-of-principle experiment is being assembled and is aimed at demonstrating FEL operation at 120 GHz with 300-kW output power in 1-microsec pulses; <span class="hlt">electron</span> energy would be 410 keV. Preliminary design of a 300-GHz 1-MW FEL with an untapered wiggler is also presented. Finally, a method of modulating high-power CW signals for radar applications is suggested.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhPl...22k2111A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhPl...22k2111A"><span id="translatedtitle">Energy exchange in strongly coupled <span class="hlt">plasmas</span> with <span class="hlt">electron</span> drift</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Akbari-Moghanjoughi, M.; Ghorbanalilu, M.</p> <p>2015-11-01</p> <p>In this paper, the generalized viscoelastic collisional quantum hydrodynamic model is employed in order to investigate the linear dielectric response of a quantum <span class="hlt">plasma</span> in the presence of strong <span class="hlt">electron</span>-beam <span class="hlt">plasma</span> interactions. The generalized Chandrasekhar's relativistic degeneracy pressure together with the <span class="hlt">electron</span>-exchange and Coulomb interaction effects are taken into account in order to extend current research to a wide range of <span class="hlt">plasma</span> number density relevant to big planetary cores and astrophysical compact objects. The previously calculated shear viscosity and the <span class="hlt">electron</span>-ion collision frequencies are used for strongly coupled ion fluid. The effect of the <span class="hlt">electron</span>-beam velocity on complex linear dielectric function is found to be profound. This effect is clearly interpreted in terms of the wave-particle interactions and their energy-exchange according to the sign of the imaginary dielectric function, which is closely related to the wave attenuation coefficient in <span class="hlt">plasmas</span>. Such kinetic effect is also shown to be in close connection with the stopping power of a charged-particle beam in a quantum <span class="hlt">plasma</span>. The effect of many independent <span class="hlt">plasma</span> parameters, such as the ion charge-state, <span class="hlt">electron</span> beam-velocity, and relativistic degeneracy, is shown to be significant on the growing/damping of <span class="hlt">plasma</span> instability or energy loss/gain of the <span class="hlt">electron</span>-beam.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22063716','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22063716"><span id="translatedtitle"><span class="hlt">Electron</span> current extraction from a permanent magnet waveguide <span class="hlt">plasma</span> cathode</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Weatherford, B. R.; Foster, J. E.; Kamhawi, H.</p> <p>2011-09-15</p> <p>An <span class="hlt">electron</span> cyclotron resonance <span class="hlt">plasma</span> produced in a cylindrical waveguide with external permanent magnets was investigated as a possible <span class="hlt">plasma</span> cathode <span class="hlt">electron</span> source. The configuration is desirable in that it eliminates the need for a physical antenna inserted into the <span class="hlt">plasma</span>, the erosion of which limits operating lifetime. <span class="hlt">Plasma</span> bulk density was found to be overdense in the source. Extraction currents over 4 A were achieved with the device. Measurements of extracted <span class="hlt">electron</span> currents were similar to calculated currents, which were estimated using Langmuir probe measurements at the <span class="hlt">plasma</span> cathode orifice and along the length of the external plume. The influence of facility effects and trace ionization in the anode-cathode gap are also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MPLB...2940030K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MPLB...2940030K"><span id="translatedtitle">Field <span class="hlt">electron</span> emission characteristics of <span class="hlt">plasma</span> treated carbon nanotubes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Koinkar, Pankaj M.; Yonekura, Daisuke; Murakami, Ri-Ichi; Moriga, Toshihiro; More, Mahendra A.</p> <p>2015-03-01</p> <p>This paper reports the effect of hydrogen (H2) <span class="hlt">plasma</span> treatment on field emission property of double walled carbon nanotubes (DWCNTs) synthesized by using chemical vapor deposition method. The hydrogen <span class="hlt">plasma</span> treatment was carried out for various duration. The DWCNTs films were characterized by using scanning <span class="hlt">electron</span> microscopy (SEM), transmission <span class="hlt">electron</span> microscopy (TEM) and Raman spectroscopy. The results showed that the field emission properties of DWCNTs were influenced with increasing <span class="hlt">plasma</span> treatment duration. The Raman spectra of samples clearly show structural defects after hydrogen <span class="hlt">plasma</span> treatment. It is observed that the change in the field emission characteristics of DWCNTs is attributed to the structural defects due to the H2 <span class="hlt">plasma</span> and depends on the <span class="hlt">plasma</span> treatment duration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/962209','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/962209"><span id="translatedtitle">Gyrokinetic <span class="hlt">Electron</span> and Fully Kinetic Ion Particle Simulation of Collisionless <span class="hlt">Plasma</span> Dynamics</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yu Lin; Xueyi Wang; Liu Chen; Zhihong Lin</p> <p>2009-08-11</p> <p>Fully kinetic-particle simulations and hybrid simulations have been utilized for decades to investigate various fundamental <span class="hlt">plasma</span> processes, such as magnetic reconnection, fast compressional waves, and wave-particle interaction. Nevertheless, due to disparate temporal and spatial scales between <span class="hlt">electrons</span> and ions, existing fully kinetic-particle codes have to employ either unrealistically high <span class="hlt">electron</span>-to-ion mass ratio, me/mi, or simulation domain limited to a few or a few ten's of the ion Larmor radii, or/and time much less than the global Alfven time scale in order to accommodate available computing resources. On the other hand, in the hybrid simulation, the ions are treated as fully kinetic particles but the <span class="hlt">electrons</span> are treated as a massless fluid. The <span class="hlt">electron</span> kinetic effects, e.g., wave-particle resonances and finite <span class="hlt">electron</span> Larmor radius effects, are completely missing. Important physics, such as the <span class="hlt">electron</span> transit time damping of fast compressional waves or the triggering mechanism of magnetic reconnection in collisionless <span class="hlt">plasmas</span> is absent in the hybrid codes. Motivated by these considerations and noting that dynamics of interest to us has frequencies lower than the <span class="hlt">electron</span> gyrofrequency, we planned to develop an innovative particle simulation model, gyrokinetic (GK) <span class="hlt">electrons</span> and fully kinetic (FK) ions. In the GK-<span class="hlt">electron</span> and FK-ion (GKe/FKi) particle simulation model, the rapid <span class="hlt">electron</span> cyclotron motion is removed, while keeping finite <span class="hlt">electron</span> Larmor radii, realistic me/mi ratio, wave-particle interactions, and off-diagonal components of <span class="hlt">electron</span> pressure tensor. The computation power can thus be significantly improved over that of the full-particle codes. As planned in the project DE-FG02-05ER54826, we have finished the development of the new GK-<span class="hlt">electron</span> and FK-ion scheme, finished its benchmark for a uniform <span class="hlt">plasma</span> in 1-D, 2-D, and 3-D systems against linear waves obtained from analytical theories, and carried out a further convergence test and benchmark for a 2-D Harris current <span class="hlt">sheet</span> against tearing mode and other instabilities in linear theories/models. More importantly, we have, for the first time, carried out simulation of linear instabilities in a 2-D Harris current <span class="hlt">sheet</span> with a broad range of guide field BG and the realistic mi/me, and obtained important new results of current <span class="hlt">sheet</span> instabilities in the presence of a finite BG. Indeed the code has accurately reproduced waves of interest here, such as kinetic Alfven waves, compressional Alfven/whistler wave, and lower-hybrid/modified two-stream waves. Moreover, this simulation scheme is capable of investigating collisionless kinetic physics relevant to magnetic reconnection in the fusion <span class="hlt">plasmas</span>, in a global scale system for a long-time evolution and, thereby, produce significant new physics compared with both full-particle and hybrid codes. The results, with mi/me=1836 and moderate to large BG as in the real laboratory devices, have not been obtained in previous theory and simulations. The new simulation model will contribute significantly not only to the understanding of fundamental fusion (and space) <span class="hlt">plasma</span> physics but also to DOE's SciDAC initiative by further pushing the frontiers of simulating realistic fusion <span class="hlt">plasmas</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22304083','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22304083"><span id="translatedtitle">Nonlinear evolution of three-dimensional instabilities of thin and thick <span class="hlt">electron</span> scale current <span class="hlt">sheets</span>: Plasmoid formation and current filamentation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jain, Neeraj; Büchner, Jörg</p> <p>2014-07-15</p> <p>Nonlinear evolution of three dimensional <span class="hlt">electron</span> shear flow instabilities of an <span class="hlt">electron</span> current <span class="hlt">sheet</span> (ECS) is studied using <span class="hlt">electron</span>-magnetohydrodynamic simulations. The dependence of the evolution on current <span class="hlt">sheet</span> thickness is examined. For thin current <span class="hlt">sheets</span> (half thickness =d{sub e}=c/ω{sub pe}), tearing mode instability dominates. In its nonlinear evolution, it leads to the formation of oblique current channels. Magnetic field lines form 3-D magnetic spirals. Even in the absence of initial guide field, the out-of-reconnection-plane magnetic field generated by the tearing instability itself may play the role of guide field in the growth of secondary finite-guide-field instabilities. For thicker current <span class="hlt">sheets</span> (half thickness ∼5 d{sub e}), both tearing and non-tearing modes grow. Due to the non-tearing mode, current <span class="hlt">sheet</span> becomes corrugated in the beginning of the evolution. In this case, tearing mode lets the magnetic field reconnect in the corrugated ECS. Later thick ECS develops filamentary structures and turbulence in which reconnection occurs. This evolution of thick ECS provides an example of reconnection in self-generated turbulence. The power spectra for both the thin and thick current <span class="hlt">sheets</span> are anisotropic with respect to the <span class="hlt">electron</span> flow direction. The cascade towards shorter scales occurs preferentially in the direction perpendicular to the <span class="hlt">electron</span> flow.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22303800','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22303800"><span id="translatedtitle">Quantum tunneling resonant <span class="hlt">electron</span> transfer process in Lorentzian <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hong, Woo-Pyo; Jung, Young-Dae</p> <p>2014-08-15</p> <p>The quantum tunneling resonant <span class="hlt">electron</span> transfer process between a positive ion and a neutral atom collision is investigated in nonthermal generalized Lorentzian <span class="hlt">plasmas</span>. The result shows that the nonthermal effect enhances the resonant <span class="hlt">electron</span> transfer cross section in Lorentzian <span class="hlt">plasmas</span>. It is found that the nonthermal effect on the classical resonant <span class="hlt">electron</span> transfer cross section is more significant than that on the quantum tunneling resonant charge transfer cross section. It is shown that the nonthermal effect on the resonant <span class="hlt">electron</span> transfer cross section decreases with an increase of the Debye length. In addition, the nonthermal effect on the quantum tunneling resonant <span class="hlt">electron</span> transfer cross section decreases with increasing collision energy. The variation of nonthermal and <span class="hlt">plasma</span> shielding effects on the quantum tunneling resonant <span class="hlt">electron</span> transfer process is also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850035938&hterms=electron+beam+atmosphere&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Delectron%2Bbeam%2Batmosphere','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850035938&hterms=electron+beam+atmosphere&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Delectron%2Bbeam%2Batmosphere"><span id="translatedtitle">Acceleration of <span class="hlt">electrons</span> in strong beam-<span class="hlt">plasma</span> interactions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wilhelm, K.; Bernstein, W.; Kellogg, P. J.; Whalen, B. A.</p> <p>1984-01-01</p> <p>The effects of strong beam-<span class="hlt">plasma</span> interactions on the <span class="hlt">electron</span> population of the upper atmosphere have been investigated in an <span class="hlt">electron</span> acceleration experiment performed with a sounding rocket. The rocket carried the Several Complex Experiments (SCEX) payload which included an <span class="hlt">electron</span> accelerator, three disposable 'throwaway' detectors (TADs), and a stepped <span class="hlt">electron</span> energy analyzer. The payload was launched in an auroral arc over the rocket at altitudes of 157 and 178 km, respectively. The performance characteristics of the instruments are discussed in detail. The data are combined with the results of laboratory measurements and show that <span class="hlt">electrons</span> with energies of at least two and probably four times the injection energy of 2 keV were observed during strong beam-<span class="hlt">plasma</span> interaction events. The interaction events occurred at pitch angles of 54 and 126 degrees. On the basis of the data it is proposed that the superenergization of the <span class="hlt">electrons</span> is correlated with the length of the beam-<span class="hlt">plasma</span> interaction region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22311133','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22311133"><span id="translatedtitle"><span class="hlt">Plasma</span> actuator <span class="hlt">electron</span> density measurement using microwave perturbation method</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mirhosseini, Farid; Colpitts, Bruce</p> <p>2014-07-21</p> <p>A cylindrical dielectric barrier discharge <span class="hlt">plasma</span> under five different pressures is generated in an evacuated glass tube. This <span class="hlt">plasma</span> volume is located at the center of a rectangular copper waveguide cavity, where the electric field is maximum for the first mode and the magnetic field is very close to zero. The microwave perturbation method is used to measure <span class="hlt">electron</span> density and <span class="hlt">plasma</span> frequency for these five pressures. Simulations by a commercial microwave simulator are comparable to the experimental results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/178190','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/178190"><span id="translatedtitle">Recent measurements of <span class="hlt">electron</span> density profiles of <span class="hlt">plasmas</span> in PLADIS I, a <span class="hlt">plasma</span> disruption simulator</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bradley, J. III; Sharp, G.; Gahl, J.M. Kuznetsov, V.; Rockett, P.; Hunter, J.</p> <p>1995-12-31</p> <p>Tokamak disruption simulation experiments are being conducted at the University of New Mexico (UNM) using the PLADIS I <span class="hlt">plasma</span> gun system. PLADIS I is a high power, high energy coaxial <span class="hlt">plasma</span> gun configured to produce an intense <span class="hlt">plasma</span> beam. First wall candidate materials are placed in the beam path to determine their response under disruption relevant energy densities. An optically thick vapor shield <span class="hlt">plasma</span> has been observed to form above the target surface in PLADIS I. Various diagnostics have been used to determine the characteristics of the incident <span class="hlt">plasma</span> and the vapor shielding <span class="hlt">plasma</span>. The cross sectional area of the incident <span class="hlt">plasma</span> beam is a critical characteristic, as it is used in the calculation of the incident <span class="hlt">plasma</span> energy density. Recently, a HeNe interferometer in the Mach-Zehnder configuration has been constructed and used to probe the <span class="hlt">electron</span> density of the incident <span class="hlt">plasma</span> beam and vapor shield <span class="hlt">plasma</span>. The object beam of the interferometer is scanned across the <span class="hlt">plasma</span> beam on successive shots, yielding line integrals of beam density on different chords through the <span class="hlt">plasma</span>. Data from the interferometer is used to determine the <span class="hlt">electron</span> density profile of the incident <span class="hlt">plasma</span> beam as a function of beam radius. This data is then used to calculate the effective beam area. Estimates. of beam area, obtained from other diagnostics such as damage targets, calorimeter arrays and off-axis measurements of surface pressure, will be compared with data from the interferometer to obtain a better estimate of the beam cross sectional area.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/950770','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/950770"><span id="translatedtitle">Ponderomotive Acceleration of Hot <span class="hlt">Electrons</span> in Tenuous <span class="hlt">Plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>V.I. Geyko and G.M. Fraiman, I.Y. Dodin and N.J. Fisch</p> <p>2009-02-17</p> <p>The oscillation-center Hamiltonian is derived for a relativistic <span class="hlt">electron</span> injected with an arbitrary momentum in a linearly polarized laser pulse propagating in tenuous <span class="hlt">plasma</span>, assuming that the pulse length is smaller than the <span class="hlt">plasma</span> wavelength. For hot <span class="hlt">electrons</span> generated at collisions with ions under intense laser drive, multiple regimes of ponderomotive acceleration are identified and the laser dispersion is shown to affect the process at <span class="hlt">plasma</span> densities down to 1017 cm−3. Assuming a/ϒg << 1, which prevents net acceleration of the cold <span class="hlt">plasma</span>, it is also shown that the normalized energy ϒ of hot <span class="hlt">electrons</span> accelerated from the initial energy ϒo < , ⌈ does not exceed ⌈ ~ aϒg, where a is the normalized laser field, and ϒg is the group velocity Lorentz factor. Yet ϒ ~ ⌈ is attained within a wide range of initial conditions; hence a cutoff in the hot <span class="hlt">electron</span> distribution is predicted.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19830062726&hterms=xu&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D50%26Ntt%3Dxu%2Bh','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19830062726&hterms=xu&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D50%26Ntt%3Dxu%2Bh"><span id="translatedtitle">An <span class="hlt">electron</span> cyclotron maser instability for astrophysical <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Freund, H. P.; Wong, H. K.; Wu, C. S.; Xu, M. J.</p> <p>1983-01-01</p> <p>The <span class="hlt">electron</span> cyclotron maser instability is analyzed for a <span class="hlt">plasma</span> which consists of a suprathermal <span class="hlt">electron</span> component characterized by velocity-space anisotropies in directions both parallel and perpendicular to the ambient magnetic field, as well as a high-density thermal <span class="hlt">plasma</span> in which omega sub e is approximately equal to Omega sub e (where omega sub e and Omega sub e are the <span class="hlt">electron</span> <span class="hlt">plasma</span> and cyclotron frequencies). The complete relativistic resonance condition is used and shown to result in a 'resonance ellipse' in momentum space. The instability is considered for both cold and warm suprathermal <span class="hlt">electron</span> distributions, and for frequencies omega approximately equal to Omega sub e in the ordinary mode and omega approximately equal to 2(Omega sub e) in the fast extraordinary mode. It is shown that the growth rates are comparable for these harmonics over a wide range of parameters which, since they are escape modes of the <span class="hlt">plasma</span>, can lead to comparable radiation intensities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21611758','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21611758"><span id="translatedtitle">Electromagnetic solitary pulses in a magnetized <span class="hlt">electron</span>-positron <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shukla, P. K.; Eliasson, B.; Stenflo, L.</p> <p>2011-03-15</p> <p>A theory for large amplitude compressional electromagnetic solitary pulses in a magnetized <span class="hlt">electron</span>-positron (e-p) <span class="hlt">plasma</span> is presented. The pulses, which propagate perpendicular to the external magnetic field, are associated with the compression of the <span class="hlt">plasma</span> density and the wave magnetic field. Here the solitary wave magnetic field pressure provides the restoring force, while the inertia comes from the equal mass <span class="hlt">electrons</span> and positrons. The solitary pulses are formed due to a balance between the compressional wave dispersion arising from the curl of the inertial forces in Faraday's law and the nonlinearities associated with the divergence of the <span class="hlt">electron</span> and positron fluxes, the nonlinear Lorentz forces, the advection of the e-p fluids, and the nonlinear <span class="hlt">plasma</span> current densities. The compressional solitary pulses can exist in a well-defined speed range above the Alfven speed. They can be associated with localized electromagnetic field excitations in magnetized laboratory and space <span class="hlt">plasmas</span> composed of <span class="hlt">electrons</span> and positrons.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001APS..DPPCO2002H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001APS..DPPCO2002H"><span id="translatedtitle">Mating <span class="hlt">Electron</span> Beam Columns to <span class="hlt">Plasma</span> Window Apertures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hershcovitch, Ady</p> <p>2001-10-01</p> <p>The <span class="hlt">Plasma</span> Window is a novel apparatus that utilizes a stabilized <span class="hlt">plasma</span> arc as an interface between vacuum and atmosphere without solid material. In addition to sustaining a vacuum atmosphere interface, the <span class="hlt">plasma</span> window has a lensing effect on charged particles. The <span class="hlt">plasma</span> current generates an azimuthal magnetic field, which exerts a radial Lorentz force on charged particles moving parallel to the current channel. With proper orientation of the current direction, the Lorentz force is radially inward. This feature can be used to focus beams to a very small spot size, and to overcome beam dispersion due to scattering by atmospheric atoms and molecules. Consequently, for a number of particle beam applications, the <span class="hlt">plasma</span> window is an attractive alternative to differential pumping. Two such applications are non-vacuum <span class="hlt">electron</span> beam welding and hypersonic wind tunnel heating. Design issues that are presently under consideration involve <span class="hlt">electron</span> beam optics due to <span class="hlt">plasma</span> window lensing effects, and preventing ions and <span class="hlt">electrons</span> from entering the beam structure. Matching <span class="hlt">electron</span> beam columns to <span class="hlt">plasma</span> windows while shielding accelerating and focusing elements from <span class="hlt">plasma</span> particles to prevent breakdowns is to be discussed in the presentation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060035418&hterms=electron+charge+mass+ratio&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Delectron%2Bcharge%2Bmass%2Bratio','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060035418&hterms=electron+charge+mass+ratio&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Delectron%2Bcharge%2Bmass%2Bratio"><span id="translatedtitle">Alfvenic Solitons in Ultrarelativistic <span class="hlt">Electron</span>-Position <span class="hlt">Plasmas</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Verheest, G. S. Lakhina F.</p> <p>1997-01-01</p> <p>In <span class="hlt">electron</span>-positron <span class="hlt">plasmas</span> some of the <span class="hlt">plasma</span> modes are decoupled due to the equal charge-to-mass ratio of both species. We derive the dispersion law for a low-frequency, generalized X-mode, which exists at all angles of propagation with respect to the static magnetic field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/9068','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/9068"><span id="translatedtitle">Accessibillity of <span class="hlt">Electron</span> Bernstein Modes in Over-Dense <span class="hlt">Plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Batchelor, D.B.; Bigelow, T.S.; Carter, M.D.</p> <p>1999-04-12</p> <p>Mode-conversion between the ordinary, extraordinary and <span class="hlt">electron</span> Bernstein modes near the <span class="hlt">plasma</span> edge may allow signals generated by <span class="hlt">electrons</span> in an over-dense <span class="hlt">plasma</span> to be detected. Alternatively, high frequency power may gain accessibility to the core <span class="hlt">plasma</span> through this mode conversion process. Many of the tools used for ion cyclotron antenna de-sign can also be applied near the <span class="hlt">electron</span> cyclotron frequency. In this paper, we investigate the possibilities for an antenna that may couple to <span class="hlt">electron</span> Bernstein modes inside an over-dense <span class="hlt">plasma</span>. The optimum values for wavelengths that undergo mode-conversion are found by scanning the poloidal and toroidal response of the <span class="hlt">plasma</span> using a warm <span class="hlt">plasma</span> slab approximation with a sheared magnetic field. Only a very narrow region of the edge can be examined in this manner; however, ray tracing may be used to follow the mode converted power in a more general geometry. It is eventually hoped that the methods can be extended to a hot <span class="hlt">plasma</span> representation. Using antenna design codes, some basic antenna shapes will be considered to see what types of antennas might be used to detect or launch modes that penetrate the cutoff layer in the edge <span class="hlt">plasma</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1986SSCom..60..705C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1986SSCom..60..705C"><span id="translatedtitle"><span class="hlt">Electron</span>-hole <span class="hlt">plasma</span> generation in gallium nitride</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cingolani, R.; Ferrara, M.; Lugarà, M.</p> <p>1986-12-01</p> <p>The <span class="hlt">electron</span>-hole <span class="hlt">plasma</span> has been studied in both epitaxial and needle GaN. The threshold and the stability of the <span class="hlt">plasma</span> are also discussed. The observed different behaviour of the samples we studied is interpreted in terms of growth technique.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NatCo...6E7248R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NatCo...6E7248R"><span id="translatedtitle">The solvation of <span class="hlt">electrons</span> by an atmospheric-pressure <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rumbach, Paul; Bartels, David M.; Sankaran, R. Mohan; Go, David B.</p> <p>2015-06-01</p> <p>Solvated <span class="hlt">electrons</span> are typically generated by radiolysis or photoionization of solutes. While <span class="hlt">plasmas</span> containing free <span class="hlt">electrons</span> have been brought into contact with liquids in studies dating back centuries, there has been little evidence that <span class="hlt">electrons</span> are solvated by this approach. Here we report direct measurements of solvated <span class="hlt">electrons</span> generated by an atmospheric-pressure <span class="hlt">plasma</span> in contact with the surface of an aqueous solution. The <span class="hlt">electrons</span> are measured by their optical absorbance using a total internal reflection geometry. The measured absorption spectrum is unexpectedly blue shifted, which is potentially due to the intense electric field in the interfacial Debye layer. We estimate an average penetration depth of 2.5+/-1.0 nm, indicating that the <span class="hlt">electrons</span> fully solvate before reacting through second-order recombination. Reactions with various <span class="hlt">electron</span> scavengers including H+, NO2-, NO3- and H2O2 show that the kinetics are similar, but not identical, to those for solvated <span class="hlt">electrons</span> formed in bulk water by radiolysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6222898','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6222898"><span id="translatedtitle">Association of an auroral surge with <span class="hlt">plasma</span> <span class="hlt">sheet</span> recovery and the retreat of the substorm neutral line</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hones, E.W. ); Elphinstone, R.; Murphree, J.S. . Dept. of Physics); Galvin, A.B. . Dept. of Space Physics); Heinemann, N.C. . Dept. of Physics); Parks, G.K. ); Rich, F.J. (Air Force Geophysics Lab., Hanscom AFB, MA</p> <p>1990-01-01</p> <p>One of the periods being studied in the PROMIS CDAW (CDAW-9) workshops is the interval 0000-1200 UT on May 3, 1986, designated Event 9C.'' A well-defined substorm, starting at 0919 UT, was imaged by both DE 1 over the southern hemisphere and Viking over the northern hemisphere. The images from Viking, at 80-second time resolution, showed a surge-like feature forming at about 0952 UT at the poleward edge of the late evening sector of the oval. The feature remained relatively stationary until about 1000 UT when it seemed to start advancing westward. ISEE 1 and 2 were closely conjugate to the surge as mapped from both the DMSP and Viking images. We conclude that the <span class="hlt">plasma</span> <span class="hlt">sheet</span> recovery was occasioned by the arrival at ISEE 1,2 of a westward traveling wave of <span class="hlt">plasma</span> <span class="hlt">sheet</span> thickening, the wave itself being formed by westward progression of the substorm neutral line's tailward retreat. The westward traveling surge was the auroral manifestation of this nonuniform retreat of the neutral line. We suggest that the upward field aligned current measured by DMSP F7 above the surge head was driven by <span class="hlt">plasma</span> velocity shear in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> at the duskward kink'' in the retreating neutral line. By analogy with this observation we propose that the westward traveling surges and the current wedge field aligned currents that characterize the expanding auroral bulge during substorm expansive phase are manifestations of (and are driven by) velocity shear in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> near the ends of the extending substorm neutral line.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22267801','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22267801"><span id="translatedtitle">Study on <span class="hlt">electron</span> beam in a low energy <span class="hlt">plasma</span> focus</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Khan, Muhammad Zubair; Ling, Yap Seong; San, Wong Chiow</p> <p>2014-03-05</p> <p><span class="hlt">Electron</span> beam emission was investigated in a low energy <span class="hlt">plasma</span> focus device (2.2 kJ) using copper hollow anode. Faraday cup was used to estimate the energy of the <span class="hlt">electron</span> beam. XR100CR X-ray spectrometer was used to explore the impact of the <span class="hlt">electron</span> beam on the target observed from top-on and side-on position. Experiments were carried out at optimized pressure of argon gas. The impact of <span class="hlt">electron</span> beam is exceptionally notable with two different approaches using lead target inside hollow anode in our <span class="hlt">plasma</span> focus device.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/968512','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/968512"><span id="translatedtitle">Properties of Trapped <span class="hlt">Electron</span> Bunches in a <span class="hlt">Plasma</span> Wakefield Accelerator</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kirby, Neil; /SLAC</p> <p>2009-10-30</p> <p><span class="hlt">Plasma</span>-based accelerators use the propagation of a drive bunch through <span class="hlt">plasma</span> to create large electric fields. Recent <span class="hlt">plasma</span> wakefield accelerator (PWFA) experiments, carried out at the Stanford Linear Accelerator Center (SLAC), successfully doubled the energy for some of the 42 GeV drive bunch <span class="hlt">electrons</span> in less than a meter; this feat would have required 3 km in the SLAC linac. This dissertation covers one phenomenon associated with the PWFA, <span class="hlt">electron</span> trapping. Recently it was shown that PWFAs, operated in the nonlinear bubble regime, can trap <span class="hlt">electrons</span> that are released by ionization inside the <span class="hlt">plasma</span> wake and accelerate them to high energies. These trapped <span class="hlt">electrons</span> occupy and can degrade the accelerating portion of the <span class="hlt">plasma</span> wake, so it is important to understand their origins and how to remove them. Here, the onset of <span class="hlt">electron</span> trapping is connected to the drive bunch properties. Additionally, the trapped <span class="hlt">electron</span> bunches are observed with normalized transverse emittance divided by peak current, {epsilon}{sub N,x}/I{sub t}, below the level of 0.2 {micro}m/kA. A theoretical model of the trapped <span class="hlt">electron</span> emittance, developed here, indicates that the emittance scales inversely with the square root of the <span class="hlt">plasma</span> density in the non-linear 'bubble' regime of the PWFA. This model and simulations indicate that the observed values of {epsilon}{sub N,x}/I{sub t} result from multi-GeV trapped <span class="hlt">electron</span> bunches with emittances of a few {micro}m and multi-kA peak currents. These properties make the trapped <span class="hlt">electrons</span> a possible particle source for next generation light sources. This dissertation is organized as follows. The first chapter is an overview of the PWFA, which includes a review of the accelerating and focusing fields and a survey of the remaining issues for a <span class="hlt">plasma</span>-based particle collider. Then, the second chapter examines the physics of <span class="hlt">electron</span> trapping in the PWFA. The third chapter uses theory and simulations to analyze the properties of the trapped <span class="hlt">electron</span> bunches. Chapters four and five present the experimental diagnostics and measurements for the trapped <span class="hlt">electrons</span>. Next, the sixth chapter introduces suggestions for future trapped <span class="hlt">electron</span> experiments. Then, Chapter seven contains the conclusions. In addition, there is an appendix chapter that covers a topic which is extraneous to <span class="hlt">electron</span> trapping, but relevant to the PWFA. This chapter explores the feasibility of one idea for the production of a hollow channel <span class="hlt">plasma</span>, which if produced could solve some of the remaining issues for a <span class="hlt">plasma</span>-based collider.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009PhDT.......158K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009PhDT.......158K"><span id="translatedtitle">Properties of trapped <span class="hlt">electron</span> bunches in a <span class="hlt">plasma</span> wakefield accelerator</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kirby, Neil Allen</p> <p></p> <p><span class="hlt">Plasma</span>-based accelerators use the propagation of a drive bunch through <span class="hlt">plasma</span> to create large electric fields. Recent <span class="hlt">plasma</span> wakefield accelerator (PWFA) experiments, carried out at the Stanford Linear Accelerator Center (SLAC), successfully doubled the energy for some of the 42 GeV drive bunch <span class="hlt">electrons</span> in less than a meter; this feat would have required 3 km in the SLAC linac. This dissertation covers one phenomenon associated with the PWFA, <span class="hlt">electron</span> trapping. Recently it was shown that PWFAs, operated in the nonlinear bubble regime, can trap <span class="hlt">electrons</span> that are released by ionization inside the <span class="hlt">plasma</span> wake and accelerate them to high energies. These trapped <span class="hlt">electrons</span> occupy and can degrade the accelerating portion of the <span class="hlt">plasma</span> wake, so it is important to understand their origins and how to remove them. Here, the onset of <span class="hlt">electron</span> trapping is connected to the drive bunch properties. Additionally, the trapped <span class="hlt">electron</span> bunches are observed with normalized transverse emittance divided by peak current, epsilonN,x/I t, below the level of 0.2 microm/kA. A theoretical model of the trapped <span class="hlt">electron</span> emittance, developed here, indicates that the emittance scales inversely with the square root of the <span class="hlt">plasma</span> density in the nonlinear "bubble" regime of the PWFA. This model and simulations indicate that the observed values of epsilonN,x/It result from multi-GeV trapped <span class="hlt">electron</span> bunches with emittances of a few mum and multi-kA peak currents. These properties make the trapped <span class="hlt">electrons</span> a possible particle source for next generation light sources. This dissertation is organized as follows. The first chapter is an overview of the PWFA, which includes a review of the accelerating and focusing fields and a survey of the remaining issues for a <span class="hlt">plasma</span>-based particle collider. Then, the second chapter examines the physics of <span class="hlt">electron</span> trapping in the PWFA. The third chapter uses theory and simulations to analyze the properties of the trapped <span class="hlt">electron</span> bunches. Chapters four and five present the experimental diagnostics and measurements for the trapped <span class="hlt">electrons</span>. Next, the sixth chapter introduces suggestions for future trapped <span class="hlt">electron</span> experiments. Then, Chapter seven contains the conclusions. In addition, there is an appendix chapter that covers a topic which is extraneous to <span class="hlt">electron</span> trapping, but relevant to the PWFA. This chapter explores the feasibility of one idea for the production of a hollow channel <span class="hlt">plasma</span>, which if produced could solve some of the remaining issues for a <span class="hlt">plasma</span>-based collider.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1061446','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1061446"><span id="translatedtitle"><span class="hlt">Electron</span> Beam Transport in Advanced <span class="hlt">Plasma</span> Wave Accelerators</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Williams, Ronald L</p> <p>2013-01-31</p> <p>The primary goal of this grant was to develop a diagnostic for relativistic <span class="hlt">plasma</span> wave accelerators based on injecting a low energy <span class="hlt">electron</span> beam (5-50keV) perpendicular to the <span class="hlt">plasma</span> wave and observing the distortion of the <span class="hlt">electron</span> beam's cross section due to the <span class="hlt">plasma</span> wave's electrostatic fields. The amount of distortion would be proportional to the <span class="hlt">plasma</span> wave amplitude, and is the basis for the diagnostic. The beat-wave scheme for producing <span class="hlt">plasma</span> waves, using two CO2 laser beam, was modeled using a leap-frog integration scheme to solve the equations of motion. Single <span class="hlt">electron</span> trajectories and corresponding phase space diagrams were generated in order to study and understand the details of the interaction dynamics. The <span class="hlt">electron</span> beam was simulated by combining thousands of single <span class="hlt">electrons</span>, whose initial positions and momenta were selected by random number generators. The model was extended by including the interactions of the <span class="hlt">electrons</span> with the CO2 laser fields of the beat wave, superimposed with the <span class="hlt">plasma</span> wave fields. The results of the model were used to guide the design and construction of a small laboratory experiment that may be used to test the diagnostic idea.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5399267','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5399267"><span id="translatedtitle">Measuring ionospheric <span class="hlt">electron</span> density using the <span class="hlt">plasma</span> frequency probe</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jensen, M.D.; Baker, K.D. )</p> <p>1992-02-01</p> <p>During the past decade, the <span class="hlt">plasma</span> frequency probe (PFP) has evolved into an accurate, proven method of measuring <span class="hlt">electron</span> density in the ionosphere above about 90 km. The instrument uses an electrically short antenna mounted on a sounding rocket that is immersed in the <span class="hlt">plasma</span> and notes the frequency where the antenna impedance is large and nonreactive. This frequency is closely related to the <span class="hlt">plasma</span> frequency, which is a direct function of free <span class="hlt">electron</span> concentration. The probe uses phase-locked loop technology to follow a changing <span class="hlt">electron</span> density. Several sections of the <span class="hlt">plasma</span> frequency probe circuitry are unique, especially the voltage-controlled oscillator that uses both an <span class="hlt">electronically</span> tuned capacitor and inductor to give the wide tuning range needed for <span class="hlt">electron</span> density measurements. The results from two recent sounding rocket flights (Thunderstorm II and CRIT II) under vastly different <span class="hlt">plasma</span> conditions demonstrate the capabilities of the PFP and show the importance of in situ <span class="hlt">electron</span> density measurements of understanding <span class="hlt">plasma</span> processes. 9 refs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22085998','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22085998"><span id="translatedtitle">Oscillating <span class="hlt">plasma</span> bubbles. III. Internal <span class="hlt">electron</span> sources and sinks</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Stenzel, R. L.; Urrutia, J. M.</p> <p>2012-08-15</p> <p>An internal <span class="hlt">electron</span> source has been used to neutralize ions injected from an ambient <span class="hlt">plasma</span> into a spherical grid. The resultant <span class="hlt">plasma</span> is termed a <span class="hlt">plasma</span> 'bubble.' When the <span class="hlt">electron</span> supply from the filament is reduced, the sheath inside the bubble becomes unstable. The <span class="hlt">plasma</span> potential of the bubble oscillates near but below the ion <span class="hlt">plasma</span> frequency. Different modes of oscillations have been observed as well as a subharmonic and multiple harmonics. The frequency increases with ion density and decreases with <span class="hlt">electron</span> density. The peak amplitude occurs for an optimum current and the instability is quenched at large <span class="hlt">electron</span> densities. The frequency also increases if Langmuir probes inside the bubble draw <span class="hlt">electrons</span>. Allowing <span class="hlt">electrons</span> from the ambient <span class="hlt">plasma</span> to enter, the bubble changes the frequency dependence on grid voltage. It is concluded that the net space charge density in the sheath determines the oscillation frequency. It is suggested that the sheath instability is caused by ion inertia in an oscillating sheath electric field which is created by ion bunching.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21333915','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21333915"><span id="translatedtitle">Simulation of laser-<span class="hlt">plasma</span> interactions and fast-<span class="hlt">electron</span> transport in inhomogeneous <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cohen, B.I. Kemp, A.J.; Divol, L.</p> <p>2010-06-20</p> <p>A new framework is introduced for kinetic simulation of laser-<span class="hlt">plasma</span> interactions in an inhomogeneous <span class="hlt">plasma</span> motivated by the goal of performing integrated kinetic simulations of fast-ignition laser fusion. The algorithm addresses the propagation and absorption of an intense electromagnetic wave in an ionized <span class="hlt">plasma</span> leading to the generation and transport of an energetic <span class="hlt">electron</span> component. The energetic <span class="hlt">electrons</span> propagate farther into the <span class="hlt">plasma</span> to much higher densities where Coulomb collisions become important. The high-density <span class="hlt">plasma</span> supports an energetic <span class="hlt">electron</span> current, return currents, self-consistent electric fields associated with maintaining quasi-neutrality, and self-consistent magnetic fields due to the currents. Collisions of the <span class="hlt">electrons</span> and ions are calculated accurately to track the energetic <span class="hlt">electrons</span> and model their interactions with the background <span class="hlt">plasma</span>. Up to a density well above critical density, where the laser electromagnetic field is evanescent, Maxwell's equations are solved with a conventional particle-based, finite-difference scheme. In the higher-density <span class="hlt">plasma</span>, Maxwell's equations are solved using an Ohm's law neglecting the inertia of the background <span class="hlt">electrons</span> with the option of omitting the displacement current in Ampere's law. Particle equations of motion with binary collisions are solved for all <span class="hlt">electrons</span> and ions throughout the system using weighted particles to resolve the density gradient efficiently. The algorithm is analyzed and demonstrated in simulation examples. The simulation scheme introduced here achieves significantly improved efficiencies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/977229','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/977229"><span id="translatedtitle">Hybrid Simulation of Laser-<span class="hlt">Plasma</span> Interactions and Fast <span class="hlt">Electron</span> Transport in Inhomogeneous <span class="hlt">Plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cohen, B I; Kemp, A; Divol, L</p> <p>2009-05-27</p> <p>A new framework is introduced for kinetic simulation of laser-<span class="hlt">plasma</span> interactions in an inhomogenous <span class="hlt">plasma</span> motivated by the goal of performing integrated kinetic simulations of fast-ignition laser fusion. The algorithm addresses the propagation and absorption of an intense electromagnetic wave in an ionized <span class="hlt">plasma</span> leading to the generation and transport of an energetic <span class="hlt">electron</span> component. The energetic <span class="hlt">electrons</span> propagate farther into the <span class="hlt">plasma</span> to much higher densities where Coulomb collisions become important. The high-density <span class="hlt">plasma</span> supports an energetic <span class="hlt">electron</span> current, return currents, self-consistent electric fields associated with maintaining quasi-neutrality, and self-consistent magnetic fields due to the currents. Collisions of the <span class="hlt">electrons</span> and ions are calculated accurately to track the energetic <span class="hlt">electrons</span> and model their interactions with the background <span class="hlt">plasma</span>. Up to a density well above critical density, where the laser electromagnetic field is evanescent, Maxwell's equations are solved with a conventional particle-based, finite-difference scheme. In the higher-density <span class="hlt">plasma</span>, Maxwell's equations are solved using an Ohm's law neglecting the inertia of the background <span class="hlt">electrons</span> with the option of omitting the displacement current in Ampere's law. Particle equations of motion with binary collisions are solved for all <span class="hlt">electrons</span> and ions throughout the system using weighted particles to resolve the density gradient efficiently. The algorithm is analyzed and demonstrated in simulation examples. The simulation scheme introduced here achieves significantly improved efficiencies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JPhCS.529a2017K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JPhCS.529a2017K"><span id="translatedtitle">Electrical conductivity of strongly degenerate <span class="hlt">plasma</span> with the account of <span class="hlt">electron-electron</span> scattering</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karakhtanov, V. S.</p> <p>2014-08-01</p> <p>The influence of <span class="hlt">electron-electron</span> scattering on the strongly degenerate <span class="hlt">plasma</span> conductivity is investigated with a linear response theory. In the present work the temperature dependence of the <span class="hlt">electron-electron</span> scattering term of the electrical conductivity and further modification of the Ziman formula are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005ApPhL..86b3509T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005ApPhL..86b3509T"><span id="translatedtitle">Magnetic suppression of secondary <span class="hlt">electrons</span> in <span class="hlt">plasma</span> immersion ion implantation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tan, Ing Hwie; Ueda, Mario; Dallaqua, Renato S.; Rossi, Jose O.</p> <p>2005-01-01</p> <p>In this work, magnetic suppression of secondary <span class="hlt">electrons</span> in <span class="hlt">plasma</span> immersion ion implantation is demonstrated experimentally in a vacuum arc system. Secondary <span class="hlt">electrons</span> emitted normally to a copper sample surface were detected by a Faraday cup, whose signal exhibited large negative spikes coincident with high voltage pulses when aluminum ions of an unmagnetized <span class="hlt">plasma</span> were implanted. When a 12.5 mT magnetic field parallel to the sample's surface is applied, these spikes are not seen, showing that secondary <span class="hlt">electrons</span> were magnetically suppressed. Another cup, oriented to detect <span class="hlt">electrons</span> that flow along the field lines, does not exhibit such negative spikes in either unmagnetized or magnetized <span class="hlt">plasmas</span>, indicating that a virtual cathode was formed by the trapped secondary <span class="hlt">electrons</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhPl...20j1612K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhPl...20j1612K"><span id="translatedtitle">Transition of <span class="hlt">electron</span> kinetics in weakly magnetized inductively coupled <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, Jin-Yong; Lee, Hyo-Chang; Kim, Young-Do; Kim, Young-Cheol; Chung, Chin-Wook</p> <p>2013-10-01</p> <p>Transition of the <span class="hlt">electron</span> kinetics from nonlocal to local regime was studied in weakly magnetized solenoidal inductively coupled <span class="hlt">plasma</span> from the measurement of the <span class="hlt">electron</span> energy probability function (EEPF). Without DC magnetic field, the discharge property was governed by nonlocal <span class="hlt">electron</span> kinetics at low gas pressure. The <span class="hlt">electron</span> temperatures were almost same in radial position, and the EEPFs in total <span class="hlt">electron</span> energy scale were radially coincided. However, when the DC magnetic field was applied, radial non-coincidence of the EEPFs in total <span class="hlt">electron</span> energy scale was observed. The <span class="hlt">electrons</span> were cooled at the discharge center where the <span class="hlt">electron</span> heating is absent, while the <span class="hlt">electron</span> temperature was rarely changed at the discharge boundary with the magnetic field. These changes show the transition from nonlocal to local <span class="hlt">electron</span> kinetics and the transition is occurred when the <span class="hlt">electron</span> gyration diameter was smaller than the skin depth. The nonlocal to local transition point almost coincided with the calculation results by using nonlocal parameter and collision parameter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009APS..GEC.BM002K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009APS..GEC.BM002K"><span id="translatedtitle">Nonlocal collisionless and collisional <span class="hlt">electron</span> transport in low temperature <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kaganovich, Igor</p> <p>2009-10-01</p> <p>The purpose of the talk is to describe recent advances in nonlocal <span class="hlt">electron</span> kinetics in low-pressure <span class="hlt">plasmas</span>. A distinctive property of partially ionized <span class="hlt">plasmas</span> is that such <span class="hlt">plasmas</span> are always in a non-equilibrium state: the <span class="hlt">electrons</span> are not in thermal equilibrium with the neutral species and ions, and the <span class="hlt">electrons</span> are also not in thermodynamic equilibrium within their own ensemble, which results in a significant departure of the <span class="hlt">electron</span> velocity distribution function from a Maxwellian. These non-equilibrium conditions provide considerable freedom to choose optimal <span class="hlt">plasma</span> parameters for applications, which make gas discharge <span class="hlt">plasmas</span> remarkable tools for a variety of <span class="hlt">plasma</span> applications, including <span class="hlt">plasma</span> processing, discharge lighting, <span class="hlt">plasma</span> propulsion, particle beam sources, and nanotechnology. Typical phenomena in such discharges include nonlocal <span class="hlt">electron</span> kinetics, nonlocal electrodynamics with collisionless <span class="hlt">electron</span> heating, and nonlinear processes in the sheaths and in the bounded <span class="hlt">plasmas</span>. Significant progress in understanding the interaction of electromagnetic fields with real bounded <span class="hlt">plasma</span> created by this field and the resulting changes in the structure of the applied electromagnetic field has been one of the major achievements of the last decade in this area of research [1-3]. We show on specific examples that this progress was made possible by synergy between full scale particle-in-cell simulations, analytical models, and experiments. In collaboration with Y. Raitses, A.V. Khrabrov, Princeton <span class="hlt">Plasma</span> Physics Laboratory, Princeton, NJ, USA; V.I. Demidov, UES, Inc., 4401 Dayton-Xenia Rd., Beavercreek, OH 45322, USA and AFRL, Wright-Patterson AFB, OH 45433, USA; and D. Sydorenko, University of Alberta, Edmonton, Canada. [4pt] [1] D. Sydorenko, A. Smolyakov, I. Kaganovich, and Y. Raitses, IEEE Trans. <span class="hlt">Plasma</span> Science 34, 895 (2006); Phys. <span class="hlt">Plasmas</span> 13, 014501 (2006); 14 013508 (2007); 15, 053506 (2008). [0pt] [2] I. D. Kaganovich, Y. Raitses, D. Sydorenko, and A. Smolyakov, Phys. <span class="hlt">Plasmas</span> 14, 057104 (2007). [0pt] [3] V.I. Demidov, C.A. DeJoseph, and A.A. Kudryavtsev, Phys. Rev. Lett. 95, 215002 (2005); V.I. Demidov, C.A. DeJoseph, J. Blessington, and M.E. Koepke, Europhysics News, 38, 21 (2007).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060009303&hterms=electric+current&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3D%2528electric%2Bcurrent%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060009303&hterms=electric+current&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3D%2528electric%2Bcurrent%2529"><span id="translatedtitle">Cluster electric current density measurements within a magnetic flux rope in the <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Slavin, J. A.; Lepping, R. P.; Gjerloev, J.; Goldstein, M. L.; Fairfield, D. H.; Acuna, M. H.; Balogh, A.; Dunlop, M.; Kivelson, M. G.; Khurana, K.</p> <p>2003-01-01</p> <p>On August 22, 2001 all 4 Cluster spacecraft nearly simultaneously penetrated a magnetic flux rope in the tail. The flux rope encounter took place in the central <span class="hlt">plasma</span> <span class="hlt">sheet</span>, Beta(sub i) approx. 1-2, near the leading edge of a bursty bulk flow. The "time-of-flight" of the flux rope across the 4 spacecraft yielded V(sub x) approx. 700 km/s and a diameter of approx.1 R(sub e). The speed at which the flux rope moved over the spacecraft is in close agreement with the Cluster <span class="hlt">plasma</span> measurements. The magnetic field profiles measured at each spacecraft were first modeled separately using the Lepping-Burlaga force-free flux rope model. The results indicated that the center of the flux rope passed northward (above) s/c 3, but southward (below) of s/c 1, 2 and 4. The peak electric currents along the central axis of the flux rope predicted by these single-s/c models were approx.15-19 nA/sq m. The 4-spacecraft Cluster magnetic field measurements provide a second means to determine the electric current density without any assumption regarding flux rope structure. The current profile determined using the curlometer technique was qualitatively similar to those determined by modeling the individual spacecraft magnetic field observations and yielded a peak current density of 17 nA/m2 near the central axis of the rope. However, the curlometer results also showed that the flux rope was not force-free with the component of the current density perpendicular to the magnetic field exceeding the parallel component over the forward half of the rope, perhaps due to the pressure gradients generated by the collision of the BBF with the inner magnetosphere. Hence, while the single-spacecraft models are very successful in fitting flux rope magnetic field and current variations, they do not provide a stringent test of the force-free condition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060013116&hterms=behavior+modeling&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dbehavior%2Bmodeling','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060013116&hterms=behavior+modeling&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dbehavior%2Bmodeling"><span id="translatedtitle">Modeling the Self-organized Critical Behavior of the <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> Reconnection Dynamics</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Klimas, Alex; Uritsky, Vadim; Baker, Daniel</p> <p>2006-01-01</p> <p>Analyses of Polar UVI auroral image data reviewed in our other presentation at this meeting (V. Uritsky, A. Klimas) show that bright night-side high-latitude UV emissions exhibit so many of the key properties of systems in self-organized criticality (SOC) that an alternate interpretation has become virtually impossible. It is now necessary to find and model the source of this behavior. We note that the most common models of self-organized criticality are numerical sandpiles. These are, at root, models that govern the transport of some quantity from a region where it is loaded to another where it is unloaded. Transport is enabled by the excitation of a local threshold instability; it is intermittent and bursty, and it exhibits a number of scale-free statistical properties. Searching for a system in the magnetosphere that is analogous and that, in addition, is known to produce auroral signatures, we focus on the reconnection dynamics of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. In our previous work, a driven reconnection model has been constructed and has been under study. The transport of electromagnetic (primarily magnetic) energy carried by the Poynting flux into the reconnection region of the model has been examined. All of the analysis techniques, and more, that have been applied to the auroral image data have also been applied to this Poynting flux. Here, we report new results showing that this model also exhibits so many of the key properties of systems in self-organized criticality that an alternate interpretation is implausible. Further, we find a strong correlation between these key properties of the model and those of the auroral UV emissions. We suggest that, in general, the driven reconnection model is an important step toward a realistic <span class="hlt">plasma</span> physical model of self-organized criticality and we conclude, more specifically, that it is also a step in the right direction toward modeling the multiscale reconnection dynamics of the magnetotail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20070017485&hterms=behavior+modeling&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dbehavior%2Bmodeling','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20070017485&hterms=behavior+modeling&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dbehavior%2Bmodeling"><span id="translatedtitle">Modeling the Self-organized Critical Behavior of Earth's <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> Reconnection Dynamics</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Klimas, Alexander J.</p> <p>2006-01-01</p> <p>Analyses of Polar UVI auroral image data show that bright night-side high-latitude W emissions exhibit so many of the key properties of systems in self-organized criticality that an alternate interpretation has become virtually impossible. These analyses will be reviewed. It is now necessary to find and model the source of this behavior. We note that the most common models of self-organized criticality are numerical sandpiles. These are, at root, models that govern the transport of some quantity from a region where it is loaded to another where it is unloaded. Transport is enabled by the excitation of a local threshold instability; it is intermittent and bursty, and it exhibits a number of scale-free statistical properties. Searching for a system in the magnetosphere that is analogous and that, in addition, is known to produce auroral signatures, we focus on the reconnection dynamics of the magnetotail <span class="hlt">plasma</span> <span class="hlt">sheet</span>. In our previous work, a driven reconnection model has been constructed and has been under study. The transport of electromagnetic (primarily magnetic) energy carried by the Poynting flux into the reconnection region of the model has been examined. All of the analysis techniques (and more) that have been applied to the auroral image data have also been applied to this Poynting flux. New results will be presented showing that this model also exhibits so many of the key properties of systems in self-organized criticality that an alternate interpretation is implausible. A strong correlation between these key properties of the model and those of the auroral UV emissions will be demonstrated. We suggest that, in general, the driven reconnection model is an important step toward a realistic <span class="hlt">plasma</span> physical model of self-organized criticality and we conclude, more specifically, that it is also a step in the right direction toward modeling the multiscale reconnection dynamics of the magnetotail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhPl...20c4502S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhPl...20c4502S"><span id="translatedtitle"><span class="hlt">Plasma</span> parameters and <span class="hlt">electron</span> energy distribution functions in a magnetically focused <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Samuell, C. M.; Blackwell, B. D.; Howard, J.; Corr, C. S.</p> <p>2013-03-01</p> <p>Spatially resolved measurements of ion density, <span class="hlt">electron</span> temperature, floating potential, and the <span class="hlt">electron</span> energy distribution function (EEDF) are presented for a magnetically focused <span class="hlt">plasma</span>. The measurements identify a central <span class="hlt">plasma</span> column displaying Maxwellian EEDFs at an <span class="hlt">electron</span> temperature of about 5 eV indicating the presence of a significant fraction of <span class="hlt">electrons</span> in the inelastic energy range (energies above 15 eV). It is observed that the EEDF remains Maxwellian along the axis of the discharge with an increase in density, at constant <span class="hlt">electron</span> temperature, observed in the region of highest magnetic field strength. Both <span class="hlt">electron</span> density and temperature decrease at the <span class="hlt">plasma</span> radial edge. <span class="hlt">Electron</span> temperature isotherms measured in the downstream region are found to coincide with the magnetic field lines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22107733','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22107733"><span id="translatedtitle"><span class="hlt">Plasma</span> parameters and <span class="hlt">electron</span> energy distribution functions in a magnetically focused <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Samuell, C. M.; Blackwell, B. D.; Howard, J.; Corr, C. S.</p> <p>2013-03-15</p> <p>Spatially resolved measurements of ion density, <span class="hlt">electron</span> temperature, floating potential, and the <span class="hlt">electron</span> energy distribution function (EEDF) are presented for a magnetically focused <span class="hlt">plasma</span>. The measurements identify a central <span class="hlt">plasma</span> column displaying Maxwellian EEDFs at an <span class="hlt">electron</span> temperature of about 5 eV indicating the presence of a significant fraction of <span class="hlt">electrons</span> in the inelastic energy range (energies above 15 eV). It is observed that the EEDF remains Maxwellian along the axis of the discharge with an increase in density, at constant <span class="hlt">electron</span> temperature, observed in the region of highest magnetic field strength. Both <span class="hlt">electron</span> density and temperature decrease at the <span class="hlt">plasma</span> radial edge. <span class="hlt">Electron</span> temperature isotherms measured in the downstream region are found to coincide with the magnetic field lines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16179470','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16179470"><span id="translatedtitle"><span class="hlt">Electron</span> <span class="hlt">plasma</span> oscillations upstream of the solar wind termination shock.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gurnett, D A; Kurth, W S</p> <p>2005-09-23</p> <p><span class="hlt">Electron</span> <span class="hlt">plasma</span> oscillations have been detected upstream of the solar wind termination shock by the <span class="hlt">plasma</span> wave instrument on the Voyager 1 spacecraft. These waves were first observed on 11 February 2004, at a heliocentric radial distance of 91.0 astronomical units, and continued sporadically with a gradually increasing occurrence rate for nearly a year. The last event occurred on 15 December 2004, at 94.1 astronomical units, just before the spacecraft crossed the termination shock. Since then, no further <span class="hlt">electron</span> <span class="hlt">plasma</span> oscillations have been observed, consistent with the spacecraft having crossed the termination shock into the heliosheath. PMID:16179470</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21124056','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21124056"><span id="translatedtitle">Femtosecond laser-induced <span class="hlt">electronic</span> <span class="hlt">plasma</span> at metal surface</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chen Zhaoyang; Mao, Samuel S.</p> <p>2008-08-04</p> <p>We develop a theoretical analysis to model <span class="hlt">plasma</span> initiation at the early stage of femtosecond laser irradiation of metal surfaces. The calculation reveals that there is a threshold intensity for the formation of a microscale <span class="hlt">electronic</span> <span class="hlt">plasma</span> at the laser-irradidated metal surface. As the full width at half maximum of a laser pulse increases from 15 to 200 fs, the <span class="hlt">plasma</span> formation threshold decreases by merely about 20%. The dependence of the threshold intensity on laser pulse width can be attributed to laser-induced surface <span class="hlt">electron</span> emission, in particular due to the effect of photoelectric effect.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E.893F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E.893F"><span id="translatedtitle">Effect of Time Dependent Bending of Current <span class="hlt">Sheets</span> in Response to Generation of <span class="hlt">Plasma</span> Jets and Reverse Currents</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Frank, Anna</p> <p></p> <p>Magnetic reconnection is a basis for many impulsive phenomena in space and laboratory <span class="hlt">plasmas</span> accompanied by effective transformation of magnetic energy. Reconnection processes usually occur in relatively thin current <span class="hlt">sheets</span> (CSs), which separate magnetic fields of different or opposite directions. We report on recent observations of time dependent bending of CSs, which results from <span class="hlt">plasma</span> dynamics inside the <span class="hlt">sheet</span>. The experiments are carried out with the CS-3D laboratory device (Institute of General Physics RAS, Moscow) [1]. The CS magnetic structure with an X line provides excitation of the Hall currents and <span class="hlt">plasma</span> acceleration from the X line to both side edges [2]. In the presence of the guide field By the Hall currents give rise to bending of the <span class="hlt">sheet</span>: the peripheral regions located away from the X line are deflected from CS middle plane (z=0) in the opposite directions z [3]. We have revealed generation of reverse currents jy near the CS edges, i.e. the currents flowing in the opposite direction to the main current in the <span class="hlt">sheet</span> [4]. There are strong grounds to believe that reverse currents are generated by the outflow <span class="hlt">plasma</span> jets [5], accelerated inside the <span class="hlt">sheet</span> and penetrated into the regions with strong normal magnetic field component Bz [4]. An impressive effect of sudden change in the sign of the CS bend has been disclosed recently, when analyzing distributions of <span class="hlt">plasma</span> density [6] and current away from the X line, in the presence of the guide field By. The CS configuration suddenly becomes opposite from that observed at the initial stage, and this effect correlates well with generation of reverse currents. Consequently this effect can be related to excitation of the reverse Hall currents owing to generation of reverse currents jy in the CS. Hence it may be concluded that CSs may exhibit time dependent vertical z-displacements, and the <span class="hlt">sheet</span> geometry depends on excitation of the Hall currents, acceleration of <span class="hlt">plasma</span> jets and generation of reverse currents. The work was supported in part by the Program (OFN-15) <span class="hlt">Plasma</span> Processes in Space and Laboratory of the Division of Physical Sciences of the Russian Academy of Sciences. 1. Frank A.G., Bogdanov S.Yu., Markov V.S. et al. // Phys. <span class="hlt">Plasmas</span> 2005. 12, 052316(1-11). 2. Frank A.G., Bugrov S.G., Markov V.S. // Phys. <span class="hlt">Plasmas</span> 2008. 15, 092102 (1-10). 3. Frank A.G., Bogdanov S.Yu., Dreiden G.V. et al. // Phys. Lett. A 2006. 348, 318-325. 4. Frank A.G., Kyrie N.P., Satunin S.N. // Phys. <span class="hlt">Plasmas</span> 2011. 18, 111209 (1-9). 5. Kyrie N.P., Markov V.S., Frank A.G. // <span class="hlt">Plasma</span> Phys. Reports 2010. 36, 357-364; JETP Lett. 2012. 95, 14-19. 6. Ostrovskaya G.V., Frank A.G. // <span class="hlt">Plasma</span> Phys. Reports 2014. 40, 21-33.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22089521','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22089521"><span id="translatedtitle">Secondary-<span class="hlt">electrons</span>-induced cathode <span class="hlt">plasma</span> in a relativistic magnetron</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Queller, T.; Gleizer, J. Z.; Krasik, Ya. E.</p> <p>2012-11-19</p> <p>Results of time- and space-resolved spectroscopic studies of cathode <span class="hlt">plasma</span> during a S-band relativistic magnetron operation and a magnetically insulated diode having an identical interelectrode gap are presented. It was shown that in the case of the magnetron operation, one obtains an earlier, more uniform <span class="hlt">plasma</span> formation due to energetic <span class="hlt">electrons</span>' interaction with the cathode surface and ionization of desorbed surface monolayers. No differences were detected in the cathode's <span class="hlt">plasma</span> temperature between the magnetron and the magnetically insulated diode operation, and no anomalous fast cathode <span class="hlt">plasma</span> expansion was observed in the magnetron at rf power up to 350 MW.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JGRA..117.3211T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JGRA..117.3211T"><span id="translatedtitle">Dynamics of long-period ULF waves in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>: Coordinated space and ground observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tian, A. M.; Zong, Q. G.; Zhang, T. L.; Nakamura, R.; Du, A. M.; Baumjohann, W.; Glassmeier, K. H.; Volwerk, M.; Hartinger, M.; Wang, Y. F.; Du, J.; Yang, B.; Zhang, X. Y.; Panov, E.</p> <p>2012-03-01</p> <p>Spacecraft and ground-based observations are used to study characteristics of ultralow frequency waves in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> from the postmidnight to morning local time sectors in the terrestrial magnetosphere. Field line resonance (FLR) type oscillations with discrete and latitude-dependent frequencies in the ranges of 1.7-2.0 and 3.0-3.2 mHz are observed in situ by the Time History of Events and Macroscale Interactions during Substorms C (THEMIS C), THEMIS D, THEMIS E, and GOES 12 spacecraft. The ground resonant oscillations in the two mentioned frequency bands are also observed at corresponding spacecraft footprints. Spectral peaks at these frequencies are observed by nearly all ground stations from premidnight to noon, with the larger-amplitude oscillations occurring in a narrow range of latitudes (3-6). The largest wave activity occurred in the magnetic local time of 05:00. The ground observations indicate westward propagation for the 1.8 mHz wave activity with an azimuthal wave number of about -2.6. The Poynting vectors from the THEMIS spacecraft show weak net energy flow (antifield aligned) toward the ionosphere of the southern hemisphere. They also show notable net energy flow toward the west. A possible interpretation is that the observed FLRs are driven by cavity and waveguide modes in the nightside outer magnetosphere after a period of long-lasting northward interplanetary magnetic field.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950029544&hterms=Evolution+tails&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DEvolution%2Btails','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950029544&hterms=Evolution+tails&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DEvolution%2Btails"><span id="translatedtitle">Influence of <span class="hlt">plasma</span> <span class="hlt">sheet</span> thickening toward the tail flanks on magnetotail stability and dynamics</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Birn, Joachim; Hesse, Michael</p> <p>1994-01-01</p> <p>On the basis of resistive MHD simulations we investigate the stability and dynamic evolution of the magnetotail for configurations with various degrees of <span class="hlt">plasma</span> <span class="hlt">sheet</span> thickening from midnight toward the tail flanks, associated with a similar increase of the B(sub z) component. This increase is varied by factors between 2 and 3.5, while the magnitude of B(sub z) at midnight is left unchanged. The increase of B(sub z) has a strong effect on the spatial extend of resistive tearing and reconnection across the tail and on the unstable evolution. For stronger thickening the cross-tail extent of the near-Earth neutral line, formed by reconnection, and correspondingly the amount of reconnected magnetic flux get reduced and the dipolarization effects earthward of the neutral line are more concentrated near midnight. An increase of B(sub z) from midnight toward the flanks by more than a factor of about 3 can possibly even suppress the resistive tearing instability. This indicates the possibility of a stability transition due to a reduction of B(sub z) in the flank regions in response to changes in the solar wind, even when the magnitude of B(sub z) near midnight and the fluctuation level in that region are unchanged (provided that a sufficient fluctuation level exists).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21537669','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21537669"><span id="translatedtitle"><span class="hlt">Electron</span> inertia effects on the planar <span class="hlt">plasma</span> sheath problem</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Duarte, V. N.; Clemente, R. A.</p> <p>2011-04-15</p> <p>The steady one-dimensional planar <span class="hlt">plasma</span> sheath problem, originally considered by Tonks and Langmuir, is revisited. Assuming continuously generated free-falling ions and isothermal <span class="hlt">electrons</span> and taking into account <span class="hlt">electron</span> inertia, it is possible to describe the problem in terms of three coupled integro-differential equations that can be numerically integrated. The inclusion of <span class="hlt">electron</span> inertia in the model allows us to obtain the value of the <span class="hlt">plasma</span> floating potential as resulting from an <span class="hlt">electron</span> density discontinuity at the walls, where the <span class="hlt">electrons</span> attain sound velocity and the electric potential is continuous. Results from numerical computation are presented in terms of plots for densities, electric potential, and particles velocities. Comparison with results from literature, corresponding to <span class="hlt">electron</span> Maxwell-Boltzmann distribution (neglecting <span class="hlt">electron</span> inertia), is also shown.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/530004','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/530004"><span id="translatedtitle">Thermal conduction by <span class="hlt">electrons</span> in hot dense <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Khalfaoui, A.H.; Bennaceur, D.</p> <p>1997-03-01</p> <p>Based on a quantum collective approach, <span class="hlt">electron</span> conduction opacity is analyzed, taking into account several nonideality effects such as <span class="hlt">electron-electron</span> (e-e) collisions in addition to <span class="hlt">electron</span>-ion collisions, dynamic shielding, <span class="hlt">electron</span> partial degeneracy, and ion coupling. The collision process is based on <span class="hlt">electron</span> wave functions interacting with the continuum oscillations (<span class="hlt">plasma</span> waves). The e-e collisions, the main nonideal effect, contribute to the thermal conductivity calculation in the intermediate coupling regime. Hence, the extensively used Lorentz gas approximation cannot be justified for <span class="hlt">plasma</span> of astrophysical interest. The present results are compared to existing theories of <span class="hlt">electron</span> conduction in stellar matter. {copyright} {ital 1997} {ital The American Astronomical Society}</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006JGRA..111.5201Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006JGRA..111.5201Z"><span id="translatedtitle">Auroral poleward boundary intensifications (PBIs): Their two-dimensional structure and associated dynamics in the <span class="hlt">plasma</span> <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zesta, E.; Lyons, L.; Wang, C.-P.; Donovan, E.; Frey, H.; Nagai, T.</p> <p>2006-05-01</p> <p>Auroral poleward boundary intensifications (PBIs) are typically seen both in ground meridian scanning photometers (MSP) and in ground and spacecraft auroral images. They appear as a localized increase in intensity at or near the magnetic separatrix. This increase is often seen to extend equatorward through the ionospheric mapping of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. PBIs are associated with <span class="hlt">plasma</span> <span class="hlt">sheet</span> flow bursts and are thus important for the remote monitoring of <span class="hlt">plasma</span> <span class="hlt">sheet</span> dynamics. From the study of simultaneous ground MSP observations, IMAGE FUV auroral images, and Geotail <span class="hlt">plasma</span> <span class="hlt">sheet</span> data, we find that PBIs correlate well with <span class="hlt">plasma</span> <span class="hlt">sheet</span> fast flows observed within the local time sector of the PBIs and that there can be several PBIs over the longitudinal range of fast flows in the tail. We infer that every north-south PBI is the ionospheric signature of a fast flow channel in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and that many fast flow channels exist simultaneously over a width of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> that can comprise the whole width of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> or only a part of it. Also, we find that there is a local time dependence on the type of PBI structure. Most PBIs are narrow auroral structures that are not strictly north-south oriented. Instead, PBIs are tilted counterclockwise away from the north-south direction, leading to a preferred orientation that is approximately aligned with a line going from 0300 magnetic local time (MLT) to 1700 MLT. This results in PBIs that are closer to north-south (NS) structures in the postmidnight sector and closer to east-west (EW) near the dusk sector. In the premidnight sector (2200-0000 MLT), PBIs start as EW arcs and then tilt and become primarily NS structures. We further found for one event that the PBI fast flows have a large Vy component resulting in tail convection that is both earthward and dawnward in the region of Geotail. We suggest that the continuous and strongly positive interplanetary magnetic field (IMF) By may order the two-dimensional convection as observed, thus offering a possible explanation for the alignment direction of PBIs in the ionosphere under the assumption that fast flow channels align themselves with the background convection. However, the projection of the PBI structures into the tail using the T96 model suggests that all PBIs, both EW and NS, map to radially stretched channels in the tail that do not have a significant dawnward component. Future work is needed to clarify this apparent contradiction. Finally, frequency analysis indicates that the PBI/bursty bulk flow (BBF) period is characterized by oscillations in the velocity and magnetic field with frequencies of 0.6 mHz and 1.3-1.5 mHz. This oscillation in velocity is superposed on the background strong convection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19880066211&hterms=1054&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2526%25231054','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19880066211&hterms=1054&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2526%25231054"><span id="translatedtitle">Field-aligned current signatures in the near-tail region. I - ISEE observations in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ohtani, S.; Kokubun, S.; Elphic, R. C.; Russell, C. T.</p> <p>1988-01-01</p> <p>Field-aligned currents in the near-tail region are examined using ISEE magnetometer data. Two substorms (the 1054 UT and the 1436 UT substorms on March 22, 1979) were examined, demonstrating the consistency of the current polarity and intensity with observations at lower altitudes, which suggests that field-aligned currents in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer are parts of the large-scale current system, the region-1 system. An examination of the steplike changes of the magnetic field direction, which correspond to the spacecraft crossing of a net field-aligned current, showed that the field-aligned currents in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer have the same polarity as the region-1 system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApPhL.106e3703L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApPhL.106e3703L"><span id="translatedtitle">Non-thermal <span class="hlt">plasma</span> mills bacteria: Scanning <span class="hlt">electron</span> microscopy observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lunov, O.; Churpita, O.; Zablotskii, V.; Deyneka, I. G.; Meshkovskii, I. K.; Jäger, A.; Syková, E.; Kubinová, Š.; Dejneka, A.</p> <p>2015-02-01</p> <p>Non-thermal <span class="hlt">plasmas</span> hold great promise for a variety of biomedical applications. To ensure safe clinical application of <span class="hlt">plasma</span>, a rigorous analysis of <span class="hlt">plasma</span>-induced effects on cell functions is required. Yet mechanisms of bacteria deactivation by non-thermal <span class="hlt">plasma</span> remain largely unknown. We therefore analyzed the influence of low-temperature atmospheric <span class="hlt">plasma</span> on Gram-positive and Gram-negative bacteria. Using scanning <span class="hlt">electron</span> microscopy, we demonstrate that both Gram-positive and Gram-negative bacteria strains in a minute were completely destroyed by helium <span class="hlt">plasma</span>. In contrast, mesenchymal stem cells (MSCs) were not affected by the same treatment. Furthermore, histopathological analysis of hematoxylin and eosin-stained rat skin sections from <span class="hlt">plasma</span>-treated animals did not reveal any abnormalities in comparison to control ones. We discuss possible physical mechanisms leading to the shred of bacteria under non-thermal <span class="hlt">plasma</span> irradiation. Our findings disclose how helium <span class="hlt">plasma</span> destroys bacteria and demonstrates the safe use of <span class="hlt">plasma</span> treatment for MSCs and skin cells, highlighting the favorability of <span class="hlt">plasma</span> applications for chronic wound therapy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19760046893&hterms=energy+radio+waves&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Denergy%2Bradio%2Bwaves','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19760046893&hterms=energy+radio+waves&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Denergy%2Bradio%2Bwaves"><span id="translatedtitle"><span class="hlt">Electron</span> <span class="hlt">plasma</span> oscillations associated with type III radio emissions and solar <span class="hlt">electrons</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gurnett, D. A.; Frank, L. A.</p> <p>1975-01-01</p> <p>Results of an extensive search for <span class="hlt">electron</span> <span class="hlt">plasma</span> oscillations associated with type III radio noise bursts are presented which were obtained by analyzing 87 type III bursts detected in <span class="hlt">plasma</span>-wave and charged-particle measurements carried out by IMP 6, 7, and 8. Only one case is found for which <span class="hlt">plasma</span> oscillations were associated with <span class="hlt">electrons</span> of solar origin; at least eight events are identified in which no <span class="hlt">plasma</span> oscillations were detected even though <span class="hlt">electrons</span> from solar flares were clearly evident. The type III emissions are compared with similar radiation coming from upstream of earth's bow shock at the harmonic of the local <span class="hlt">electron</span> <span class="hlt">plasma</span> frequency, and quantitative calculations of the rate of conversion from <span class="hlt">plasma</span> oscillatory energy to electromagnetic radiation are performed. The results show that <span class="hlt">electron</span> <span class="hlt">plasma</span> oscillations are seldom observed in association with solar <span class="hlt">electron</span> events and type III radio bursts at 1.0 AU and that neither the type III emissions nor the radiation from upstream of the bow shock can be adequately explained by a current model for the coupling of <span class="hlt">electron</span> <span class="hlt">plasma</span> oscillations to electromagnetic radiation. Several possible explanations are considered for this discrepancy between theory and observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22072533','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22072533"><span id="translatedtitle">Three-wave coupling in <span class="hlt">electron</span>-positron-ion <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tinakiche, N.; Annou, R.; Tripathi, V. K.</p> <p>2012-07-15</p> <p>The three-wave coupling processes in <span class="hlt">electron</span>-positron-ion <span class="hlt">plasmas</span> are investigated. The non-linear dispersion relation is derived along with the non-linear growth rate in both resonant and non resonant processes. It is shown that the inclusion of positron affects the dielectric properties of the <span class="hlt">plasma</span> as well as the nonlinear growth rates of parametric processes. As one increases the positron density to <span class="hlt">electron</span> density ratio from 0 to 1, maintaining quasi neutrality of the <span class="hlt">plasma</span>, the growth rates of stimulated Raman, Brillouin, and Compton scattering processes in an isothermal <span class="hlt">plasma</span> tend to zero due to the ponderomotive forces acting on <span class="hlt">electrons</span> and positrons due the pump and scattered waves being equal.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/901850','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/901850"><span id="translatedtitle">Ionization-Induced <span class="hlt">Electron</span> Trapping inUltrarelativistic <span class="hlt">Plasma</span> Wakes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Oz, E.; Deng, S.; Katsouleas, T.; Muggli, P.; Barnes, C.D.; Blumenfeld, I.; Decker, F.J.; Emma, P.; Hogan, M.J.; Ischebeck, R.; Iverson, R.H.; Kirby, N.; Krejcik, P.; O'Connell, C.; Siemann, R.H.; Walz, D.; Auerbach, D.; Clayton, C.E.; Huang, C.; Johnson, D.K.; Joshi, C.; /UCLA</p> <p>2007-04-06</p> <p>The onset of trapping of <span class="hlt">electrons</span> born inside a highly relativistic, 3D beam-driven <span class="hlt">plasma</span> wake is investigated. Trapping occurs in the transition regions of a Li <span class="hlt">plasma</span> confined by He gas. Li <span class="hlt">plasma</span> <span class="hlt">electrons</span> support the wake, and higher ionization potential He atoms are ionized as the beam is focused by Li ions and can be trapped. As the wake amplitude is increased, the onset of trapping is observed. Some <span class="hlt">electrons</span> gain up to 7.6 GeV in a 30.5 cm <span class="hlt">plasma</span>. The experimentally inferred trapping threshold is at a wake amplitude of 36 GV/m, in good agreement with an analytical model and PIC simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22408263','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22408263"><span id="translatedtitle">Effect of secondary <span class="hlt">electron</span> emission on the <span class="hlt">plasma</span> sheath</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Langendorf, S. Walker, M.</p> <p>2015-03-15</p> <p>In this experiment, <span class="hlt">plasma</span> sheath potential profiles are measured over boron nitride walls in argon <span class="hlt">plasma</span> and the effect of secondary <span class="hlt">electron</span> emission is observed. Results are compared to a kinetic model. <span class="hlt">Plasmas</span> are generated with a number density of 3 × 10{sup 12} m{sup −3} at a pressure of 10{sup −4} Torr-Ar, with a 1%–16% fraction of energetic primary <span class="hlt">electrons</span>. The sheath potential profile at the surface of each sample is measured with emissive probes. The <span class="hlt">electron</span> number densities and temperatures are measured in the bulk <span class="hlt">plasma</span> with a planar Langmuir probe. The <span class="hlt">plasma</span> is non-Maxwellian, with isotropic and directed energetic <span class="hlt">electron</span> populations from 50 to 200 eV and hot and cold Maxwellian populations from 3.6 to 6.4 eV and 0.3 to 1.3 eV, respectively. <span class="hlt">Plasma</span> Debye lengths range from 4 to 7 mm and the ion-neutral mean free path is 0.8 m. Sheath thicknesses range from 20 to 50 mm, with the smaller thickness occurring near the critical secondary <span class="hlt">electron</span> emission yield of the wall material. Measured floating potentials are within 16% of model predictions. Measured sheath potential profiles agree with model predictions within 5 V (∼1 T{sub e}), and in four out of six cases deviate less than the measurement uncertainty of 1 V.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22303448','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22303448"><span id="translatedtitle"><span class="hlt">Electron</span> energy distributions in a magnetized inductively coupled <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Song, Sang-Heon E-mail: Sang-Heon.Song@us.tel.com; Yang, Yang; Kushner, Mark J.</p> <p>2014-09-15</p> <p>Optimizing and controlling <span class="hlt">electron</span> energy distributions (EEDs) is a continuing goal in <span class="hlt">plasma</span> materials processing as EEDs determine the rate coefficients for <span class="hlt">electron</span> impact processes. There are many strategies to customize EEDs in low pressure inductively coupled <span class="hlt">plasmas</span> (ICPs), for example, pulsing and choice of frequency, to produce the desired <span class="hlt">plasma</span> properties. Recent experiments have shown that EEDs in low pressure ICPs can be manipulated through the use of static magnetic fields of sufficient magnitudes to magnetize the <span class="hlt">electrons</span> and confine them to the electromagnetic skin depth. The EED is then a function of the local magnetic field as opposed to having non-local properties in the absence of the magnetic field. In this paper, EEDs in a magnetized inductively coupled <span class="hlt">plasma</span> (mICP) sustained in Ar are discussed with results from a two-dimensional <span class="hlt">plasma</span> hydrodynamics model. Results are compared with experimental measurements. We found that the character of the EED transitions from non-local to local with application of the static magnetic field. The reduction in cross-field mobility increases local <span class="hlt">electron</span> heating in the skin depth and decreases the transport of these hot <span class="hlt">electrons</span> to larger radii. The tail of the EED is therefore enhanced in the skin depth and depressed at large radii. <span class="hlt">Plasmas</span> densities are non-monotonic with increasing pressure with the external magnetic field due to transitions between local and non-local kinetics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhPl...22c3515L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhPl...22c3515L"><span id="translatedtitle">Effect of secondary <span class="hlt">electron</span> emission on the <span class="hlt">plasma</span> sheath</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Langendorf, S.; Walker, M.</p> <p>2015-03-01</p> <p>In this experiment, <span class="hlt">plasma</span> sheath potential profiles are measured over boron nitride walls in argon <span class="hlt">plasma</span> and the effect of secondary <span class="hlt">electron</span> emission is observed. Results are compared to a kinetic model. <span class="hlt">Plasmas</span> are generated with a number density of 3 1012 m-3 at a pressure of 10-4 Torr-Ar, with a 1%-16% fraction of energetic primary <span class="hlt">electrons</span>. The sheath potential profile at the surface of each sample is measured with emissive probes. The <span class="hlt">electron</span> number densities and temperatures are measured in the bulk <span class="hlt">plasma</span> with a planar Langmuir probe. The <span class="hlt">plasma</span> is non-Maxwellian, with isotropic and directed energetic <span class="hlt">electron</span> populations from 50 to 200 eV and hot and cold Maxwellian populations from 3.6 to 6.4 eV and 0.3 to 1.3 eV, respectively. <span class="hlt">Plasma</span> Debye lengths range from 4 to 7 mm and the ion-neutral mean free path is 0.8 m. Sheath thicknesses range from 20 to 50 mm, with the smaller thickness occurring near the critical secondary <span class="hlt">electron</span> emission yield of the wall material. Measured floating potentials are within 16% of model predictions. Measured sheath potential profiles agree with model predictions within 5 V (1 Te), and in four out of six cases deviate less than the measurement uncertainty of 1 V.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhPl...17d3111W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhPl...17d3111W"><span id="translatedtitle"><span class="hlt">Electron</span> beam transport analysis of W-band <span class="hlt">sheet</span> beam klystron</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Jian-Xun; Barnett, Larry R.; Luhmann, Neville C.; Shin, Young-Min; Humphries, Stanley</p> <p>2010-04-01</p> <p>The formation and transport of high-current density <span class="hlt">electron</span> beams are of critical importance for the success of a number of millimeter wave and terahertz vacuum devices. To elucidate design issues and constraints, the <span class="hlt">electron</span> gun and periodically cusped magnet stack of the original Stanford Linear Accelerator Center designed W-band <span class="hlt">sheet</span> beam klystron circuit, which exhibited poor beam transmission (≤55%), have been carefully investigated through theoretical and numerical analyses taking advantage of three-dimensional particle tracking solvers. The re-designed transport system is predicted to exhibit 99.76% (cold) and 97.38% (thermal) beam transmission, respectively, under space-charge-limited emission simulations. The optimized design produces the required high aspect ratio (10:1) <span class="hlt">sheet</span> beam with 3.2 A emission current with highly stable propagation. In the completely redesigned model containing all the circuit elements, more than 99% beam transmission is experimentally observed at the collector located about 160 mm distant from the cathode surface. Results are in agreement of the predictions of two ray-tracing simulators, CST PARTICLE STUDIO and OMNITRAK which also predict the observed poor transmission in the original design. The quantitative analysis presents practical factors in the modeling process to design a magnetic lens structure to stably transport the elliptical beam along the long drift tube.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25280344','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25280344"><span id="translatedtitle"><span class="hlt">Electron</span> backscatter diffraction applied to lithium <span class="hlt">sheets</span> prepared by broad ion beam milling.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Brodusch, Nicolas; Zaghib, Karim; Gauvin, Raynald</p> <p>2015-01-01</p> <p>Due to its very low hardness and atomic number, pure lithium cannot be prepared by conventional methods prior to scanning <span class="hlt">electron</span> microscopy analysis. Here, we report on the characterization of pure lithium metallic <span class="hlt">sheets</span> used as base electrodes in the lithium-ion battery technology using <span class="hlt">electron</span> backscatter diffraction (EBSD) and X-ray microanalysis using energy dispersive spectroscopy (EDS) after the <span class="hlt">sheet</span> surface was polished by broad argon ion milling (IM). No grinding and polishing were necessary to achieve the sufficiently damage free necessary for surface analysis. Based on EDS results the impurities could be characterized and EBSD revealed the microsctructure and microtexture of this material with accuracy. The beam damage and oxidation/hydration resulting from the intensive use of IM and the transfer of the sample into the microscope chamber was estimated to be <50 nm. Despite the fact that the IM process generates an increase of temperature at the specimen surface, it was assumed that the milling parameters were sufficient to minimize the heating effect on the surface temperature. However, a cryo-stage should be used if available during milling to guaranty a heating artefact free surface after the milling process. PMID:25280344</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006cosp...36.1532S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006cosp...36.1532S"><span id="translatedtitle">Current system in the top ionosphere generated relativistic <span class="hlt">electrons</span>, let out by a cloud of radioactive <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stupitsky, E. L.; Kurnosov, V. V.; Lavrinenko, N. E.</p> <p></p> <p>In experiments such as Starfisch extending radioactive <span class="hlt">plasma</span> radiates into a geomagnetic ionosphere a powerful stream of relativistic <span class="hlt">electrons</span> Being distributed along a geomagnetic field beta-<span class="hlt">electrons</span> form self-coordinated current system and generate electromagnetic indignations Using 3D calculations of behaviour of a cloud of radioactive <span class="hlt">plasma</span> and numerical modelling of movement beta-<span class="hlt">electrons</span> inside and outside of a <span class="hlt">plasma</span> cloud the share from total emitted <span class="hlt">electrons</span> which is capable to be grasped by the non-uniform geomagnetic field superseded from <span class="hlt">plasma</span> is determined and to participate in formation current system It is shown that the radius of the current tube depends on radial distribution of <span class="hlt">plasma</span> and in a non-uniform magnetic field it is much less than the radius of the sphere The amplitude of the current is proportional to activity of the <span class="hlt">plasma</span> source and inside this source essentially depends on the speed of leaving <span class="hlt">electrons</span> into tubes of current The dynamics of <span class="hlt">electrons</span> in a tube of current their interaction with the top ionosphere and the self-coordinated electric field was calculated numerically on the basis of a method of <span class="hlt">plasma</span> <span class="hlt">sheets</span> It is shown that if the height of a <span class="hlt">plasma</span> source exceeds 120 km there is an effect of partial lock-out of an output of <span class="hlt">electrons</span> under the self-coordinated electric field If the height of the source is about 300 km then in 5 cdot 10 -3 second a quasistationary mode of development of current system is realized Thus the first group of <span class="hlt">electrons</span> penetrating to the on heights of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JAP...117a3301T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JAP...117a3301T"><span id="translatedtitle">Numerical model of the <span class="hlt">plasma</span> formation at <span class="hlt">electron</span> beam welding</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Trushnikov, D. N.; Mladenov, G. M.</p> <p>2015-01-01</p> <p>The model of <span class="hlt">plasma</span> formation in the keyhole in liquid metal as well as above the <span class="hlt">electron</span> beam welding zone is described. The model is based on solution of two equations for the density of <span class="hlt">electrons</span> and the mean <span class="hlt">electron</span> energy. The mass transfer of heavy <span class="hlt">plasma</span> particles (neutral atoms, excited atoms, and ions) is taken into account in the analysis by the diffusion equation for a multicomponent mixture. The electrostatic field is calculated using the Poisson equation. Thermionic <span class="hlt">electron</span> emission is calculated for the keyhole wall. The ionization intensity of the vapors due to beam <span class="hlt">electrons</span> and high-energy secondary and backscattered <span class="hlt">electrons</span> is calibrated using the <span class="hlt">plasma</span> parameters when there is no polarized collector electrode above the welding zone. The calculated data are in good agreement with experimental data. Results for the <span class="hlt">plasma</span> parameters for excitation of a non-independent discharge are given. It is shown that there is a need to take into account the effect of a strong electric field near the keyhole walls on <span class="hlt">electron</span> emission (the Schottky effect) in the calculation of the current for a non-independent discharge (hot cathode gas discharge). The calculated <span class="hlt">electron</span> drift velocities are much bigger than the velocity at which current instabilities arise. This confirms the hypothesis for ion-acoustic instabilities, observed experimentally in previous research.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22218608','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22218608"><span id="translatedtitle">Coupled <span class="hlt">electron</span> and ion nonlinear oscillations in a collisionless <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Karimov, A. R.</p> <p>2013-05-15</p> <p>Dynamics of coupled electrostatic <span class="hlt">electron</span> and ion nonlinear oscillations in a collisionless <span class="hlt">plasma</span> is studied with reference to a kinetic description. Proceeding from the exact solution of Vlasov-Maxwell equations written as a function of linear functions in the <span class="hlt">electron</span> and ion velocities, we arrive at the two coupled nonlinear equations which describe the evolution of the system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22399196','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22399196"><span id="translatedtitle">Numerical model of the <span class="hlt">plasma</span> formation at <span class="hlt">electron</span> beam welding</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Trushnikov, D. N.; Mladenov, G. M.</p> <p>2015-01-07</p> <p>The model of <span class="hlt">plasma</span> formation in the keyhole in liquid metal as well as above the <span class="hlt">electron</span> beam welding zone is described. The model is based on solution of two equations for the density of <span class="hlt">electrons</span> and the mean <span class="hlt">electron</span> energy. The mass transfer of heavy <span class="hlt">plasma</span> particles (neutral atoms, excited atoms, and ions) is taken into account in the analysis by the diffusion equation for a multicomponent mixture. The electrostatic field is calculated using the Poisson equation. Thermionic <span class="hlt">electron</span> emission is calculated for the keyhole wall. The ionization intensity of the vapors due to beam <span class="hlt">electrons</span> and high-energy secondary and backscattered <span class="hlt">electrons</span> is calibrated using the <span class="hlt">plasma</span> parameters when there is no polarized collector electrode above the welding zone. The calculated data are in good agreement with experimental data. Results for the <span class="hlt">plasma</span> parameters for excitation of a non-independent discharge are given. It is shown that there is a need to take into account the effect of a strong electric field near the keyhole walls on <span class="hlt">electron</span> emission (the Schottky effect) in the calculation of the current for a non-independent discharge (hot cathode gas discharge). The calculated <span class="hlt">electron</span> drift velocities are much bigger than the velocity at which current instabilities arise. This confirms the hypothesis for ion-acoustic instabilities, observed experimentally in previous research.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PlPhR..41..737V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PlPhR..41..737V"><span id="translatedtitle"><span class="hlt">Electron</span>-ion relaxation time in moderately degenerate <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vronskii, M. A.; Koryakina, Yu. V.</p> <p>2015-09-01</p> <p>A formula is derived for the <span class="hlt">electron</span>-ion relaxation time in a partially degenerate <span class="hlt">plasma</span> with <span class="hlt">electron</span>-ion interaction via a central field. The resulting expression in the form of an integral of the transport cross section generalizes the well-known Landau and Brysk approximations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPSJ...85c4707O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPSJ...85c4707O"><span id="translatedtitle">Structural Stability and <span class="hlt">Electronic</span> Structures of a Curved Graphene <span class="hlt">Sheet</span> on Stepped SiC(0001) Surface</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ono, Youky; Nara, Jun; Ohno, Takahisa</p> <p>2016-03-01</p> <p>The structural stabilities and <span class="hlt">electronic</span> structures of graphene <span class="hlt">sheets</span> laid on stepped SiC(0001) surfaces are theoretically investigated by density functional theory calculations. To precisely estimate the van der Waals (vdW) binding energy between graphene <span class="hlt">sheets</span> and SiC surfaces, the vdW density functional (vdW-DF) was used. We have found that a graphene <span class="hlt">sheet</span> put over a stepped SiC surface has a curved structure bridging the upper and lower terraces without making any bonds to the atoms of the step. This bridging curved structure of the graphene <span class="hlt">sheet</span> is mainly stabilized by the vdW attraction force. With respect to the <span class="hlt">electronic</span> structure, the original sp2 network is maintained in the curved graphene <span class="hlt">sheet</span>. By comparing the local density of states (LDOS) of carbon atoms in the curved graphene <span class="hlt">sheet</span>, we also found that the <span class="hlt">electronic</span> structure of each carbon atom largely depends on the distance between the carbon atom and the surface.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19780019971','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19780019971"><span id="translatedtitle">Microwave radiation measurements near the <span class="hlt">electron</span> <span class="hlt">plasma</span> frequency of the NASA Lewis bumpy torus <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mallavarpu, R.; Roth, J. R.</p> <p>1978-01-01</p> <p>Microwave emission near the <span class="hlt">electron</span> <span class="hlt">plasma</span> frequency was observed, and its relation to the average <span class="hlt">electron</span> density and the dc toroidal magnetic field was examined. The emission was detected using a spectrum analyzer and a 50 omega miniature coaxial probe. The radiation appeared as a broad amplitude peak that shifted in frequency as the <span class="hlt">plasma</span> parameters were varied. The observed radiation scanned an average <span class="hlt">plasma</span> density ranging from 10 million/cu cm to 8 hundred million/cu cm. A linear relation was observed betweeen the density calculated from the emission frequency and the average <span class="hlt">plasma</span> density measured with a microwave interferometer. With the aid of a relative density profile measurement of the <span class="hlt">plasma</span>, it was determined that the emissions occurred from the outer periphery of the <span class="hlt">plasma</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6525482','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6525482"><span id="translatedtitle">A reflex <span class="hlt">electron</span> beam discharge as a <span class="hlt">plasma</span> source for <span class="hlt">electron</span> beam generation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Murray, C.S.; Rocca, J.J.; Szapiro, B. )</p> <p>1988-10-01</p> <p>A reflex <span class="hlt">electron</span> beam glow discharge has been used as a <span class="hlt">plasma</span> source for the generation of broad-area <span class="hlt">electron</span> beams. An <span class="hlt">electron</span> current of 120 A (12 A/cm/sup 2/) was extracted from the <span class="hlt">plasma</span> in 10 ..mu..s pulses and accelerated to energies greater than 1 keV in the gap between two grids. The scaling of the scheme for the generation of multikiloamp high-energy beams is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/870998','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/870998"><span id="translatedtitle">Method for generating a <span class="hlt">plasma</span> wave to accelerate <span class="hlt">electrons</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Umstadter, Donald; Esarey, Eric; Kim, Joon K.</p> <p>1997-01-01</p> <p>The invention provides a method and apparatus for generating large amplitude nonlinear <span class="hlt">plasma</span> waves, driven by an optimized train of independently adjustable, intense laser pulses. In the method, optimal pulse widths, interpulse spacing, and intensity profiles of each pulse are determined for each pulse in a series of pulses. A resonant region of the <span class="hlt">plasma</span> wave phase space is found where the <span class="hlt">plasma</span> wave is driven most efficiently by the laser pulses. The accelerator system of the invention comprises several parts: the laser system, with its pulse-shaping subsystem; the <span class="hlt">electron</span> gun system, also called beam source, which preferably comprises photo cathode <span class="hlt">electron</span> source and RF-LINAC accelerator; <span class="hlt">electron</span> photo-cathode triggering system; the <span class="hlt">electron</span> diagnostics; and the feedback system between the <span class="hlt">electron</span> diagnostics and the laser system. The system also includes <span class="hlt">plasma</span> source including vacuum chamber, magnetic lens, and magnetic field means. The laser system produces a train of pulses that has been optimized to maximize the axial electric field amplitude of the <span class="hlt">plasma</span> wave, and thus the <span class="hlt">electron</span> acceleration, using the method of the invention.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/doepatents/biblio/489098','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/doepatents/biblio/489098"><span id="translatedtitle">Method for generating a <span class="hlt">plasma</span> wave to accelerate <span class="hlt">electrons</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Umstadter, D.; Esarey, E.; Kim, J.K.</p> <p>1997-06-10</p> <p>The invention provides a method and apparatus for generating large amplitude nonlinear <span class="hlt">plasma</span> waves, driven by an optimized train of independently adjustable, intense laser pulses. In the method, optimal pulse widths, interpulse spacing, and intensity profiles of each pulse are determined for each pulse in a series of pulses. A resonant region of the <span class="hlt">plasma</span> wave phase space is found where the <span class="hlt">plasma</span> wave is driven most efficiently by the laser pulses. The accelerator system of the invention comprises several parts: the laser system, with its pulse-shaping subsystem; the <span class="hlt">electron</span> gun system, also called beam source, which preferably comprises photo cathode <span class="hlt">electron</span> source and RF-LINAC accelerator; <span class="hlt">electron</span> photo-cathode triggering system; the <span class="hlt">electron</span> diagnostics; and the feedback system between the <span class="hlt">electron</span> diagnostics and the laser system. The system also includes <span class="hlt">plasma</span> source including vacuum chamber, magnetic lens, and magnetic field means. The laser system produces a train of pulses that has been optimized to maximize the axial electric field amplitude of the <span class="hlt">plasma</span> wave, and thus the <span class="hlt">electron</span> acceleration, using the method of the invention. 21 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19820058707&hterms=harp&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dharp','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19820058707&hterms=harp&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dharp"><span id="translatedtitle">Suprathermal <span class="hlt">electrons</span> produced by beam-<span class="hlt">plasma</span>-discharge</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sharp, W. E.</p> <p>1982-01-01</p> <p>Experiments conducted with a low energy <span class="hlt">plasma</span> lens, HARP, in the <span class="hlt">electron</span> beam of the large vacuum chamber at Johnson Space Center indicate that an enhanced population of 50 to 300 volt <span class="hlt">electrons</span> appear when the beam goes into the Beam-<span class="hlt">Plasma</span> Discharge (BPD) mode. Below the BPD instability the <span class="hlt">electron</span> distribution appears to be characterized as non-energized single particle scattering and energy loss. At 100 cm from the beam core in the BPD mode the fluxes parallel to the beam are reduced by a factor of 20 with respect to the fluxes at 25 cm. Some evidence for isotropy near the beam core is presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6685054','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6685054"><span id="translatedtitle">Suprathermal <span class="hlt">electrons</span> produced by Beam-<span class="hlt">Plasma</span>-Discharge</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sharp, W.E.</p> <p>1982-08-01</p> <p>Experiments conducted with a low energy <span class="hlt">plasma</span> lens, HARP, in the <span class="hlt">electron</span> beam of the large vacuum chamber at Johnson Space Center indicate that an enhanced population of 50 to 300 volt <span class="hlt">electrons</span> appear when the beam goes into the Beam-<span class="hlt">Plasma</span> Discharge (BPD) mode. Below the BPD instability the <span class="hlt">electron</span> distribution appears to be characterized as non-energized single particle scattering and energy loss. At 100 cm from the beam core in the BPD mode the fluxes parallel to the beam are reduced by a factor of 20 with respect to the fluxes at 25 cm. Some evidence for isotropy near the beam core is presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010ApPhL..96g1502F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010ApPhL..96g1502F"><span id="translatedtitle">A high current density <span class="hlt">plasma</span> cathode <span class="hlt">electron</span> gun</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fu, Wenjie; Yan, Yang; Li, Wenxu; Li, Xiaoyun; Wu, Jianqiang</p> <p>2010-02-01</p> <p>The design, performance, and characteristics of a <span class="hlt">plasma</span> cathode <span class="hlt">electron</span> gun are presented. The <span class="hlt">plasma</span> cathode is based on a hollow cathode direct current discharge, and the <span class="hlt">electron</span> beam is accelerated by pulse voltage. By discharging at high gas pressure and operating at low gas pressure, both the maximum accelerating voltage and maximum emitting current could be increased. Utilizing argon, with the accelerating voltage up to 9 kV and gas pressure down to 52 mPa, the gun is able to generate an <span class="hlt">electron</span> beam of about 4.7 A, and the corresponding emitting current density is about 600 A/cm2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22068878','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22068878"><span id="translatedtitle">Kinetic description of <span class="hlt">electron</span> <span class="hlt">plasma</span> waves with orbital angular momentum</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mendonca, J. T.</p> <p>2012-11-15</p> <p>We describe the kinetic theory of <span class="hlt">electron</span> <span class="hlt">plasma</span> waves with orbital angular momentum or twisted plasmons. The conditions for a twisted Landau resonance to exist are established, and this concept is introduced for the first time. Expressions for the kinetic dispersion relation and for the <span class="hlt">electron</span> Landau damping are derived. The particular case of a Maxwellian <span class="hlt">plasma</span> is examined in detail. The new contributions to wave dispersion and damping due the orbital angular momentum are discussed. It is shown that twisted plasmons can be excited by rotating <span class="hlt">electron</span> beams.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21347274','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21347274"><span id="translatedtitle">A high current density <span class="hlt">plasma</span> cathode <span class="hlt">electron</span> gun</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fu Wenjie; Yan Yang; Li Wenxu; Li Xiaoyun; Wu Jianqiang</p> <p>2010-02-15</p> <p>The design, performance, and characteristics of a <span class="hlt">plasma</span> cathode <span class="hlt">electron</span> gun are presented. The <span class="hlt">plasma</span> cathode is based on a hollow cathode direct current discharge, and the <span class="hlt">electron</span> beam is accelerated by pulse voltage. By discharging at high gas pressure and operating at low gas pressure, both the maximum accelerating voltage and maximum emitting current could be increased. Utilizing argon, with the accelerating voltage up to 9 kV and gas pressure down to 52 mPa, the gun is able to generate an <span class="hlt">electron</span> beam of about 4.7 A, and the corresponding emitting current density is about 600 A/cm{sup 2}.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvB..93l5410P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvB..93l5410P"><span id="translatedtitle">Bulk and shear viscosities of the two-dimensional <span class="hlt">electron</span> liquid in a doped graphene <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Principi, Alessandro; Vignale, Giovanni; Carrega, Matteo; Polini, Marco</p> <p>2016-03-01</p> <p>Hydrodynamic flow occurs in an <span class="hlt">electron</span> liquid when the mean free path for <span class="hlt">electron-electron</span> collisions is the shortest length scale in the problem. In this regime, transport is described by the Navier-Stokes equation, which contains two fundamental parameters, the bulk and shear viscosities. In this paper, we present extensive results for these transport coefficients in the case of the two-dimensional massless Dirac fermion liquid in a doped graphene <span class="hlt">sheet</span>. Our approach relies on microscopic calculations of the viscosities up to second order in the strength of <span class="hlt">electron-electron</span> interactions and in the high-frequency limit, where perturbation theory is applicable. We then use simple interpolation formulas that allow to reach the low-frequency hydrodynamic regime where perturbation theory is no longer directly applicable. The key ingredient for the interpolation formulas is the "viscosity transport time" τv, which we calculate in this paper. The transverse nature of the excitations contributing to τv leads to the suppression of scattering events with small momentum transfer, which are inherently longitudinal. Therefore, contrary to the quasiparticle lifetime, which goes as -1 /[T2ln(T /TF) ] , in the low-temperature limit we find τv˜1 /T2 .</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22420281','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22420281"><span id="translatedtitle">Non-thermal <span class="hlt">plasma</span> mills bacteria: Scanning <span class="hlt">electron</span> microscopy observations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lunov, O. Churpita, O.; Zablotskii, V.; Jäger, A.; Dejneka, A.; Deyneka, I. G.; Meshkovskii, I. K.; Syková, E.; Kubinová, Š.</p> <p>2015-02-02</p> <p>Non-thermal <span class="hlt">plasmas</span> hold great promise for a variety of biomedical applications. To ensure safe clinical application of <span class="hlt">plasma</span>, a rigorous analysis of <span class="hlt">plasma</span>-induced effects on cell functions is required. Yet mechanisms of bacteria deactivation by non-thermal <span class="hlt">plasma</span> remain largely unknown. We therefore analyzed the influence of low-temperature atmospheric <span class="hlt">plasma</span> on Gram-positive and Gram-negative bacteria. Using scanning <span class="hlt">electron</span> microscopy, we demonstrate that both Gram-positive and Gram-negative bacteria strains in a minute were completely destroyed by helium <span class="hlt">plasma</span>. In contrast, mesenchymal stem cells (MSCs) were not affected by the same treatment. Furthermore, histopathological analysis of hematoxylin and eosin–stained rat skin sections from plasma–treated animals did not reveal any abnormalities in comparison to control ones. We discuss possible physical mechanisms leading to the shred of bacteria under non-thermal <span class="hlt">plasma</span> irradiation. Our findings disclose how helium <span class="hlt">plasma</span> destroys bacteria and demonstrates the safe use of <span class="hlt">plasma</span> treatment for MSCs and skin cells, highlighting the favorability of <span class="hlt">plasma</span> applications for chronic wound therapy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.6427Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.6427Y"><span id="translatedtitle">Formation and evolution of high-<span class="hlt">plasma</span>-pressure region in the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span>: Precursor and postcursor of substorm expansion onset</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yao, Y.; Ebihara, Y.; Tanaka, T.</p> <p>2015-08-01</p> <p>Cause of substorm expansion onset is one of the major problems in the magnetospheric study. On the basis of a global magnetohydrodynamic (MHD) simulation, Tanaka et al. (2010) suggested that formation and evolution of a high-pressure region (HPR) in the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> could result in sudden intensification of the Region 1 field-aligned current and the westward auroral electrojet. In this sense, the formation and evolution of the HPR are a key in understanding the cause of the onset. On 5 April 2009, three probes of the Time History of Events and Macroscale Interactions during Substorms (THEMIS) were located at XGSM~-11 Re around the equator, which provide unique opportunity to investigate the spatial-temporal evolution of the HPR near the substorm expansion onset. Just before the onset, a positive excursion of the <span class="hlt">plasma</span> pressure appeared at the outermost probe first, followed by the inner ones. Just after the onset, the opposite sequence took place. A positive excursion of the Y component of the current density was observed near the onset by the THEMIS probes and followed by a decrease trend. A similar variation was also found in the MHD simulation. All these features are consistent with the simulation result that a squeeze of the <span class="hlt">plasma</span> from the <span class="hlt">plasma</span> <span class="hlt">sheet</span> results in the formation of the HPR before the onset and that the accumulated <span class="hlt">plasma</span> spreads outward after the onset. The HPR is shown to be important for the dynamics of the magnetosphere during a substorm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20774496','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20774496"><span id="translatedtitle">Bremsstrahlung neutrinos from <span class="hlt">electron-electron</span> scattering in a relativistic degenerate <span class="hlt">electron</span> <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jaikumar, Prashanth; Gale, Charles; Page, Dany</p> <p>2005-12-15</p> <p>We present a calculation of neutrino pair bremsstrahlung due to <span class="hlt">electron-electron</span> scattering in a relativistic degenerate <span class="hlt">plasma</span> of <span class="hlt">electrons</span>. Proper treatment of the in-medium photon propagator, i.e., inclusion of Debye screening of the longitudinal part and Landau damping of the transverse part, leads to a neutrino emissivity which is several orders of magnitude larger than when Debye screening is imposed for the tranverse part. Our results show that this in-medium process can compete with other sources of neutrino radiation and can, in some cases, even be the dominant neutrino emission mechanism. We also discuss the natural extension to quark-quark bremsstrahlung in gapped and ungapped quark matter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6734987','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/6734987"><span id="translatedtitle">dc-<span class="hlt">plasma</span>-sprayed <span class="hlt">electronic</span>-tube device</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Meek, T.T.</p> <p>1982-01-29</p> <p>An <span class="hlt">electronic</span> tube and associated circuitry which is produced by dc <span class="hlt">plasma</span> arc spraying techniques is described. The process is carried out in a single step automated process whereby both active and passive devices are produced at very low cost. The circuitry is extremely reliable and is capable of functioning in both high radiation and high temperature environments. The size of the <span class="hlt">electronic</span> tubes produced are more than an order of magnitude smaller than conventional <span class="hlt">electronic</span> tubes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AIPC..669..358B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AIPC..669..358B"><span id="translatedtitle">Fore-Vacuum <span class="hlt">Plasma</span> <span class="hlt">Electron</span> Gun of Ribbon Beam</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Burdovitsin, Viktor; Burachevsky, Yurii; Oks, Efim; Fedorov, Michael</p> <p>2003-06-01</p> <p><span class="hlt">Plasma</span> <span class="hlt">electron</span> gun for ribbon beam generation was designed on the basis of glow discharge with hollow cathode. <span class="hlt">Electrons</span> were extracted through emission hole in the anode from <span class="hlt">plasma</span> boundary, stabilized by metal mesh, and accelerated by the voltage applied between the anode and extractor. <span class="hlt">Electron</span> beam was of 25 cm width, 1 cm thickness. Beam current and energy were of 0.1-1 A and 2-6 keV respectively, at gas pressure of 10 - 60 mTorr. Maximum parameters are defined mostly by the acceleration gap geometry. Current density distribution along the beam width depends on the gas pressure and total beam current. At pressures higher than 30 mTorr local current maximums appear in the <span class="hlt">electron</span> beam. They look as streams, and their positions are determined by the anode mesh deviation from flatness, but they are always at the edges of the beam. Our experiments show that in the absence of <span class="hlt">electron</span> emission <span class="hlt">plasma</span> density distribution in a hollow cathode maintains maximums at edges but their amounts are not more than 5 percents. At the same time, local beam maximums are about two times more. It means there is another reason of non-uniformity. We believe this intensifying is caused by gas ionization in the acceleration gap and back-stream ion flow to discharge <span class="hlt">plasma</span>. Recharging in <span class="hlt">plasma</span>, these ions increase <span class="hlt">plasma</span> density and that, in its turn, leads to stream intensifying and so on. Local <span class="hlt">plasma</span> density growth is balanced by ion diffusion from this excite zone. Lower pressure, lower ion back flow and lower <span class="hlt">plasma</span> non-uniformity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22118560','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22118560"><span id="translatedtitle">Two-dimensional-spatial distribution measurement of <span class="hlt">electron</span> temperature and <span class="hlt">plasma</span> density in low temperature <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kim, Young-Cheol; Jang, Sung-Ho; Oh, Se-Jin; Lee, Hyo-Chang; Chung, Chin-Wook</p> <p>2013-05-15</p> <p>A real-time measurement method for two-dimensional (2D) spatial distribution of the <span class="hlt">electron</span> temperature and <span class="hlt">plasma</span> density was developed. The method is based on the floating harmonic method and the real time measurement is achieved with little <span class="hlt">plasma</span> perturbation. 2D arrays of the sensors on a 300 mm diameter wafer-shaped printed circuit board with a high speed multiplexer circuit were used. Experiments were performed in an inductive discharge under various external conditions, such as powers, gas pressures, and different gas mixing ratios. The results are consistent with theoretical prediction. Our method can measure the 2D spatial distribution of <span class="hlt">plasma</span> parameters on a wafer-level in real-time. This method can be applied to <span class="hlt">plasma</span> diagnostics to improve the <span class="hlt">plasma</span> uniformity of <span class="hlt">plasma</span> reactors for <span class="hlt">plasma</span> processing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23742549','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23742549"><span id="translatedtitle">Two-dimensional-spatial distribution measurement of <span class="hlt">electron</span> temperature and <span class="hlt">plasma</span> density in low temperature <span class="hlt">plasmas</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kim, Young-Cheol; Jang, Sung-Ho; Oh, Se-Jin; Lee, Hyo-Chang; Chung, Chin-Wook</p> <p>2013-05-01</p> <p>A real-time measurement method for two-dimensional (2D) spatial distribution of the <span class="hlt">electron</span> temperature and <span class="hlt">plasma</span> density was developed. The method is based on the floating harmonic method and the real time measurement is achieved with little <span class="hlt">plasma</span> perturbation. 2D arrays of the sensors on a 300 mm diameter wafer-shaped printed circuit board with a high speed multiplexer circuit were used. Experiments were performed in an inductive discharge under various external conditions, such as powers, gas pressures, and different gas mixing ratios. The results are consistent with theoretical prediction. Our method can measure the 2D spatial distribution of <span class="hlt">plasma</span> parameters on a wafer-level in real-time. This method can be applied to <span class="hlt">plasma</span> diagnostics to improve the <span class="hlt">plasma</span> uniformity of <span class="hlt">plasma</span> reactors for <span class="hlt">plasma</span> processing. PMID:23742549</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004APS..DPPPP1119F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004APS..DPPPP1119F"><span id="translatedtitle">Pattern Formation by Passage Through Resonances in Pure <span class="hlt">Electron</span> <span class="hlt">Plasmas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Friedland, Lazar</p> <p>2004-11-01</p> <p>Transverse dynamics of trapped pure <span class="hlt">electron</span> <span class="hlt">plasmas</span> can be modeled by Euler's equations of ideal fluids. A class of uniform m-fold symmetric <span class="hlt">plasma</span>/vortex equilibria in this approximation were discovered by Deem and Zabusky [1], but creation of these states required some nontrivial initial conditions. I will describe a more realizable approach to formation of non-axisymmetric, shape preserving patterns in non-uniform <span class="hlt">plasmas</span>. We start from an axisymmetric <span class="hlt">plasma</span> equilibrium, but add an oscillatory driving potential of an appropriate spatial symmetry. We chirp the driving frequency and pass through resonances with either a discrete Kelvin mode [2] or a continuum of "kinetic" modes of the initial <span class="hlt">plasma</span> equilibrium. Under certain conditions, the driven system enters a persistent, nonlinear resonance regime, yielding a nontrivial, shape-preserving <span class="hlt">plasma</span> state in the process of evolution. The "kinetic" application is related to excitation of synchronized BGK modes in pure <span class="hlt">electron</span> <span class="hlt">plasmas</span> by passage through axial bounce resonances [3,4]. Work supported by the Israel Science Foundation and INTAS. [1] G. Deem and N. Zabusky, Phys. Rev. Lett. 40, 859 (1978). [2] L. Friedland and A. Shagalov, Phys. Fluids 14, 3074 (2002). [3] W. Bertsche, J. Fajans, and L. Friedland, Phys. Rev. Lett. 91, 265003 (2003). [4] L. Friedland et al, Phys. <span class="hlt">Plasmas</span> (September, 2004).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996APS..DPP..9R01P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996APS..DPP..9R01P"><span id="translatedtitle">Proton Beam Tests of an <span class="hlt">Electron</span> <span class="hlt">Plasma</span> Target</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pollock, R.; Stoller, D.; Sarrazine, A.; Gerberich, H.; Sloan, T.</p> <p>1996-11-01</p> <p>Stored protons of 45 MeV striking a non-neutral <span class="hlt">electron</span> <span class="hlt">plasma</span> have shown the stability of a beam-target system. The <span class="hlt">plasma</span> had a length of 0.5 m, with 10^10 <span class="hlt">electrons</span> maintained in a steady state by torque from a rotating electric quadrupole field and thermal energy from a noise source. A <span class="hlt">plasma</span> temperature of a few eV allowed ionization of background gas to regulate <span class="hlt">electron</span> number. Proton beam currents up to 0.2 mA were used, either coasting (no time structure) or bunched (rf cavity and <span class="hlt">electron</span> cooling) to form narrow pulses. Coasting beam was observed to heat the <span class="hlt">electron</span> <span class="hlt">plasma</span> consistent with energy transfer via particle collisions, limiting the luminosity to about 10^24cm-2s-1, useful for atomic physics research. A higher trap B field with radiation cooling would raise this limit. Bunched beam gave extra heating, which varied with <span class="hlt">plasma</span> length, indicating a resonance of a standing density wave with a harmonic of the 1.03 MHz orbit frequency. Increased radial transport was observed after exposure to the proton beam, probably caused by patchy-charge deposits on trap surfaces, and alleviated by raising the wall temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22094033','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22094033"><span id="translatedtitle">Separation of finite <span class="hlt">electron</span> temperature effect on <span class="hlt">plasma</span> polarimetry</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Imazawa, Ryota; Kawano, Yasunori; Kusama, Yoshinori</p> <p>2012-12-15</p> <p>This study demonstrates the separation of the finite <span class="hlt">electron</span> temperature on the <span class="hlt">plasma</span> polarimetry in the magnetic confined fusion <span class="hlt">plasma</span> for the first time. Approximate solutions of the transformed Stokes equation, including the relativistic effect, suggest that the orientation angle, {theta}, and ellipticity angle, {epsilon}, of polarization state have different dependency on the <span class="hlt">electron</span> density, n{sub e}, and the <span class="hlt">electron</span> temperature, T{sub e}, and that the separation of n{sub e} and T{sub e} from {theta} and {epsilon} is possible in principle. We carry out the equilibrium and kinetic reconstruction of tokamak <span class="hlt">plasma</span> when the central <span class="hlt">electron</span> density was 10{sup 20} m{sup -3}, and the central <span class="hlt">electron</span> temperatures were 5, 10, 20, and 30 keV. For both cases when a total <span class="hlt">plasma</span> current, I{sub p}, is known and when I{sub p} is unknown, the profiles of <span class="hlt">plasma</span> current density, j{sub {phi}}, n{sub e}, and T{sub e} are successfully reconstructed. The reconstruction of j{sub {phi}} without the information of I{sub p} indicates the new method of I{sub p} measurement applicable to steady state operation of tokamak.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010APS..DPPGI3005S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010APS..DPPGI3005S"><span id="translatedtitle">Formation of High-Beta <span class="hlt">Plasma</span> and Stable Confinement of Toroidal <span class="hlt">Electron</span> <span class="hlt">Plasma</span> in RT-1</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saitoh, Haruhiko</p> <p>2010-11-01</p> <p>The Ring Trap 1 (RT-1) device is a laboratory magnetosphere generated by a levitated superconducting magnet. The goals of RT-1 are to realize stable formation of ultra high-beta <span class="hlt">plasma</span> suitable for burning advanced fusion fuels, and confinement of toroidal non-neutral <span class="hlt">plasmas</span> including antimatter particles. RT- 1 has produced high-beta <span class="hlt">plasma</span> in the magnetospheric configuration. The effects of coil levitation and geomagnetic field compensation [Y. Yano et al., <span class="hlt">Plasma</span> Fusion Res. 4, 039] resulted drastic improvements of the <span class="hlt">plasma</span> properties, and a maximum local beta value exceeded 70%. Because <span class="hlt">plasma</span> is generated by <span class="hlt">electron</span> cyclotron resonance heating (ECH) in the present experiment, the <span class="hlt">plasma</span> pressure is mainly due to hot <span class="hlt">electrons</span>, whose bremsstrahlung was observed with an x-ray CCD camera. The pressure profiles have rather steep gradient near the superconducting coil in the strong field region. The decay rates of magnetic probe and interferometer signals have different time constants, suggesting multiple temperature components. The energy confinement time estimated from the input RF power and stored magnetic energy is on the order of 1s, which is comparable to the decay time constant of the density of hot <span class="hlt">electron</span> component. Pure <span class="hlt">electron</span> <span class="hlt">plasma</span> experiments are also conducted in RT-1. Radial profiles of electrostatic potential and <span class="hlt">electron</span> density showed that the <span class="hlt">plasma</span> rigidly rotates in the toroidal direction in the stable confinement phase. Long time confinement of toroidal non- neutral <span class="hlt">plasma</span> for more than 300s and inward particle diffusion to strong field regions, caused by the activation of the diocotron (Kelvin-Helmholtz) instability, have been realized [Z. Yoshida et al., Phys. Rev. Lett. 104, 235004].</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19770010909','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19770010909"><span id="translatedtitle"><span class="hlt">Electron</span> dynamics in a <span class="hlt">plasma</span> focus. [<span class="hlt">electron</span> acceleration</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hohl, F.; Gary, S. P.; Winters, P. A.</p> <p>1977-01-01</p> <p>Results are presented of a numerical integration of the three-dimensional relativistic equations of motion of <span class="hlt">electrons</span> subject to given electric and magnetic fields deduced from experiments. Fields due to two different models are investigated. For the first model, the fields are those due to a circular distribution of axial current filaments. As the current filaments collapse toward the axis, large azimuthal magnetic and axial electric fields are induced. These fields effectively heat the <span class="hlt">electrons</span> to a temperature of approximately 8 keV and accelerate <span class="hlt">electrons</span> within the radius of the filaments to high axial velocities. Similar results are obtained for the current-reduction phase of focus formation. For the second model, the fields are those due to a uniform current distribution. Both the current-reduction and the compression phases were studied. These is little heating or acceleration of <span class="hlt">electrons</span> during the compression phase because the <span class="hlt">electrons</span> are tied to the magnetic field. However, during the current-reduction phase, <span class="hlt">electrons</span> near the axis are accelerated toward the center electrode and reach energies of 100 keV. A criterion is obtained which limits the runaway <span class="hlt">electron</span> current to about 400 A.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009JAP...106a3717N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009JAP...106a3717N"><span id="translatedtitle">Terahertz spectroscopy of <span class="hlt">plasma</span> waves in high <span class="hlt">electron</span> mobility transistors</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nouvel, P.; Marinchio, H.; Torres, J.; Palermo, C.; Gasquet, D.; Chusseau, L.; Varani, L.; Shiktorov, P.; Starikov, E.; Gruinskis, V.</p> <p>2009-07-01</p> <p>We report on systematic measurements of resonant <span class="hlt">plasma</span> waves oscillations in several gate-length InGaAs high <span class="hlt">electron</span> mobility transistors (HEMTs) and compare them with numerical results from a specially developed model. A great concern of experiments has been to ensure that HEMTs were not subject to any spurious <span class="hlt">electronic</span> oscillation that may interfere with the desired <span class="hlt">plasma</span>-wave spectroscopy excited via a terahertz optical beating. The influence of geometrical HEMTs parameters as well as biasing conditions is then explored extensively owing to many different devices. <span class="hlt">Plasma</span> resonances up to the terahertz are observed. A numerical approach, based on hydrodynamic equations coupled to a pseudo-two-dimensional Poisson solver, has been developed and is shown to render accurately from experiments. Using a combination of experimental results and numerical simulations all at once, a comprehensive spectroscopy of <span class="hlt">plasma</span> waves in HEMTs is provided with a deep insight into the physical processes that are involved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..DPPTP8062C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..DPPTP8062C"><span id="translatedtitle">Effects of <span class="hlt">Electron</span> Emission on <span class="hlt">Plasma</span>-Surface Interaction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Campanell, Michael; Wang, Hongyue; Khrabrov, Alexander; Kaganovich, Igor</p> <p>2013-10-01</p> <p>Most models of sheaths facing emitting surfaces invoke assumptions that the sheath is time-independent, the wall potential is negative, ions enter the sheath at Bohm velocity, the presheath is weakly affected, and one wall is considered. We present theory and PIC simulations showing that these assumptions can break down in practice. When emission is strong, the sheath potential can become positive, repelling ions from the wall. Emitted <span class="hlt">electrons</span> entering the <span class="hlt">plasma</span> can drastically affect the presheath structure too. If their mean-free-path is large, emitted <span class="hlt">electrons</span> can transit the <span class="hlt">plasma</span> and impact the opposite wall; hence wall charging becomes a complex global problem. Secondary emission can trigger sheath instabilities preventing <span class="hlt">plasma</span>-wall systems from reaching steady state. Implications are discussed for tokamaks, Hall thrusters, dusty <span class="hlt">plasmas</span>, hot cathodes, RF discharges and spacecraft. This work was supported by the U.S. DOE under contract no. DE-AC02-09CH11466, and by AFOSR.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFMSM51B1298P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFMSM51B1298P"><span id="translatedtitle">Theory and Simulations of Auroral Undulations Associated with Instabilities in the Dusk Sector <span class="hlt">Plasma</span> <span class="hlt">Sheet</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Perez, J. C.; Horton, W.; Lewis, W. S.; Burch, J.; Goldstein, J.; Frey, H.; Anderson, P.</p> <p>2005-12-01</p> <p>Ion drift wave theory and simulations of large-scale auroral undulations are presented for the observations in Lewis et al (2005). These undulations are identified as a nonlinear stage of the drift balloning-interchange mode in the presence of a sheared E×B flow for high Richardson's number in the dusk sector of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. The system is ideal MHD stable. Theoretical density, temperature and pressure profiles are constructed and constrained from data and used as input for a 2-1/2 D nonlinear Chebyshev-Fourier-tau pseudospectral code which reproduces the undulation structure to a good degree. Undulations were observed on February 6, 2002 along the equatorward edge of the auroral oval with the Far-Ultraviolet Wideband Imaging Camera on NASA's IMAGE satellite during the recovery phase of a moderate magnetic storm. The undulations occurred in the 18.5-14.5 magnetic local time sector between 63° and 71° magnetic latitude. Their wavelength and crest-to-base length averaged 292~km and 224~km, respectively; and they propagated westward with an average speed of 0.90±0.06~km/s. Such undulations are a relatively uncommon auroral phenomenon, and the mechanism that produce them and the magnetospheric conditions under which they occur are not well understood. Work supported by the National Science Foundation. [1] W.~S. Lewis, J.~L. Burch, J. Goldstein, W. Horton, J.~C. Perez, H.~U. Frey and P.~C. Anderson, submitted to GRL (2005).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRA..119.7199L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRA..119.7199L"><span id="translatedtitle">Classification of fast flows in central <span class="hlt">plasma</span> <span class="hlt">sheet</span>: Superposed epoch analysis based on THEMIS observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, H.; Wang, C.; Fu, S. Y.</p> <p>2014-09-01</p> <p>A statistical survey of 560 fast flows in midnight central <span class="hlt">plasma</span> <span class="hlt">sheet</span> is performed based on Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations during its first two tail phases. From superposed epoch analysis, no significant substorm activities are found to be associated with the occurrence of fast flows beyond X=-15 Re. Considering the associations with substorm activities, the fast flows inside of X=-15 Re can be classified into two obvious classes: short duration (< 2.0 min) and long duration (> 4.0 min). Substorm breakups are shown to be more closely correlated to short-duration fast flows. Furthermore, the onset of short-duration fast flows in the dipolarization region (X=-9 to -11 Re) is almost simultaneous with the onset of substorm breakups and dipolarizations. On the other hand, time delays of 2-4 min are both found in the near-Earth region (X=-7 to -9 Re) and in the near-tail region (X=-11 to -15 Re). Assuming that short-duration fast flows are generated by the force imbalance caused by cross-tail current disruption, these features are consistent with the predictions made by the cowling electrojet current loop and the cross-tail current disruption substorm models. In comparison, although more magnetic flux is transported toward Earth for long-duration fast flows, no clear substorm breakup is closely associated with them. The analysis of 2-D ion velocity distribution further shows some differences. For short-duration fast flows, multiple crescent-shaped ion populations are found. However, for long-duration fast flows, there exists only a single crescent-shaped ion population. The difference may be an important signature for distinguishing these two classes of fast flows.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20669980','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20669980"><span id="translatedtitle"><span class="hlt">Electronic</span> properties of the biphenylene <span class="hlt">sheet</span> and its one-dimensional derivatives.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hudspeth, Mathew A; Whitman, Brandon W; Barone, Veronica; Peralta, Juan E</p> <p>2010-08-24</p> <p>We have studied the <span class="hlt">electronic</span> properties and relative stability of the biphenylene <span class="hlt">sheet</span> composed of alternating eight-, six- and four-carbon rings and its one-dimensional derivatives including ribbons and tubes of different widths and morphologies by means of density functional theory calculations. The two-dimensional <span class="hlt">sheet</span> presents a metallic character that is also present in the planar strips with zigzag-type edges. Armchair-edged strips develop a band gap that decreases monotonically with the ribbon width. The narrowest armchair strip considered here (0.62 nm wide) presents a large band gap of 1.71 eV, while the 2.14 nm wide armchair strip exhibits a band gap of 0.08 eV. We have also found that tubes made by rolling these ribbons in a seamlessly manner are all metallic, independent of their chirality. However, while the calculated energy landscape suggests that planar strips present a relative stability comparable to that of C(60), in the tubular form, they present a more pronounced metastable nature with a Gibbs free energy of at least 0.2 eV per carbon higher than in C(60). PMID:20669980</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000PhyS...61..489K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000PhyS...61..489K"><span id="translatedtitle">Kinetic Theory of Vortex Crystal Formation in <span class="hlt">Electron</span> <span class="hlt">Plasmas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kono, M.; Pécseli, H. L.; Trulsen, J.</p> <p></p> <p>Vortex-like structures in two dimensional strongly magnetized <span class="hlt">plasmas</span> are studied by use of a point vortex description. A model equation describing the dynamics of point vortices under the influence of fluctuations is derived, and by a numerical solution it is demonstrated that it has self-organizing properties. The numerical results have many similarities with experimental observations of crystal-like structures found in strongly magnetized <span class="hlt">electron</span> <span class="hlt">plasmas</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21347403','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21347403"><span id="translatedtitle">The functionalization of graphene using <span class="hlt">electron</span>-beam generated <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Baraket, M.; Walton, S. G.; Lock, E. H.; Robinson, J. T.; Perkins, F. K.</p> <p>2010-06-07</p> <p>A <span class="hlt">plasmas</span>-based, reversible functionalization of graphene is discussed. Using <span class="hlt">electron</span>-beam produced <span class="hlt">plasmas</span>, oxygen and fluorine functionalities have been added by changing the processing gas mixtures from Ar/O{sub 2} to Ar/SF{sub 6}, respectively. The reversibility of the functionalization was investigated by annealing the samples. The chemical composition and structural changes were studied by x-ray photoelectron spectroscopy and Raman spectroscopy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20699677','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20699677"><span id="translatedtitle">Collisionless Reconnection in an <span class="hlt">Electron</span>-Positron <span class="hlt">Plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bessho, N.; Bhattacharjee, A.</p> <p>2005-12-09</p> <p>Electromagnetic particle-in-cell simulations of fast collisionless reconnection in a two-dimensional <span class="hlt">electron</span>-positron <span class="hlt">plasma</span> (without an equilibrium guide field) are presented. A generalized Ohm's law in which the Hall current cancels out exactly is given. It is suggested that the key to fast reconnection in this <span class="hlt">plasma</span> is the localization caused by the off-diagonal components of the pressure tensors, which produce an effect analogous to a spatially localized resistivity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21255224','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21255224"><span id="translatedtitle">Direct Acceleration of <span class="hlt">Electrons</span> in a Corrugated <span class="hlt">Plasma</span> Channel</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Palastro, J. P.; Antonsen, T. M.; Morshed, S.; York, A. G.; Layer, B.; Aubuchon, M.; Milchberg, H. M.; Froula, D. H.</p> <p>2009-01-22</p> <p>Direct laser acceleration of <span class="hlt">electrons</span> provides a low power tabletop alternative to laser wakefield accelerators. Until recently, however, direct acceleration has been limited by diffraction, phase matching, and material damage thresholds. The development of the corrugated <span class="hlt">plasma</span> channel [B. Layer et al., Phys. Rev. Lett. 99, 035001 (2007)] has removed all of these limitations and promises to allow direct acceleration of <span class="hlt">electrons</span> over many centimeters at high gradients using femtosecond lasers [A. G. York et al., Phys Rev. Lett 100, 195001 (2008), J. P. Palastro et al., Phys. Rev. E 77, 036405 (2008)]. We present a simple analytic model of laser propagation in a corrugated <span class="hlt">plasma</span> channel and examine the laser-<span class="hlt">electron</span> beam interaction. Simulations show accelerating gradients of several hundred MeV/cm for laser powers much lower than required by standard laser wakefield schemes. In addition, the laser provides a transverse force that confines the high energy <span class="hlt">electrons</span> on axis, while expelling low energy <span class="hlt">electrons</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870053861&hterms=1076&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D%2526%25231076','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870053861&hterms=1076&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D%2526%25231076"><span id="translatedtitle"><span class="hlt">Plasma</span> properties in <span class="hlt">electron</span>-bombardment ion thrusters</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Matossian, J. N.; Beattie, J. R.</p> <p>1987-01-01</p> <p>The paper describes a technique for computing volume-averaged <span class="hlt">plasma</span> properties within <span class="hlt">electron</span>-bombardment ion thrusters, using spatially varying Langmuir-probe measurements. Average values of the <span class="hlt">electron</span> densities are defined by integrating the spatially varying Maxwellian and primary <span class="hlt">electron</span> densities over the ionization volume, and then dividing by the volume. <span class="hlt">Plasma</span> properties obtained in the 30-cm-diameter J-series and ring-cusp thrusters are analyzed by the volume-averaging technique. The superior performance exhibited by the ring-cusp thruster is correlated with a higher average Maxwellian <span class="hlt">electron</span> temperature. The ring-cusp thruster maintains the same fraction of primary <span class="hlt">electrons</span> as does the J-series thruster, but at a much lower ion production cost. The volume-averaged predictions for both thrusters are compared with those of a detailed thruster performance model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6384383','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6384383"><span id="translatedtitle"><span class="hlt">Plasma</span> properties in <span class="hlt">electron</span>-bombardment ion thrusters</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Matossian, J.N.; Beattie, J.R.</p> <p>1987-05-01</p> <p>The paper describes a technique for computing volume-averaged <span class="hlt">plasma</span> properties within <span class="hlt">electron</span>-bombardment ion thrusters, using spatially varying Langmuir-probe measurements. Average values of the <span class="hlt">electron</span> densities are defined by integrating the spatially varying Maxwellian and primary <span class="hlt">electron</span> densities over the ionization volume, and then dividing by the volume. <span class="hlt">Plasma</span> properties obtained in the 30-cm-diameter J-series and ring-cusp thrusters are analyzed by the volume-averaging technique. The superior performance exhibited by the ring-cusp thruster is correlated with a higher average Maxwellian <span class="hlt">electron</span> temperature. The ring-cusp thruster maintains the same fraction of primary <span class="hlt">electrons</span> as does the J-series thruster, but at a much lower ion production cost. The volume-averaged predictions for both thrusters are compared with those of a detailed thruster performance model. 20 references.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000RScI...71..388G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000RScI...71..388G"><span id="translatedtitle">High current, low pressure <span class="hlt">plasma</span> cathode <span class="hlt">electron</span> gun</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goebel, Dan M.; Watkins, Ron M.</p> <p>2000-02-01</p> <p>A <span class="hlt">plasma</span>-cathode <span class="hlt">electron</span> gun based on a moderate pressure (>5 mTorr) cold-cathode discharge and a high perveance, multiaperture accelerator was previously developed at Hughes Research Laboratories and produced <span class="hlt">electron</span> beam currents of up to 1 kA at voltages of over 200 kV for pulse lengths of 100 ?s. This gun was limited in pulse repetition frequency and duty by the gas-puff system that provided adequate gas pressure in the hollow cathode to operate the glow discharge while keeping the pressure in the beam transport region sufficiently low. We describe a new <span class="hlt">plasma</span> cathode <span class="hlt">electron</span> gun (PCE gun) that eliminates this problem by replacing the glow-discharge <span class="hlt">plasma</span> generator in the <span class="hlt">electron</span> gun by a low-pressure thermionic discharge in a magnetic multipole confinement chamber. Proper design of the <span class="hlt">plasma</span> generator and electrical circuit provides high <span class="hlt">electron</span>-current densities to the accelerator structure at very low gas pressure (<10-4 Torr). The static gas pressure permits the pulse repetition frequency to be very high (>1.5 kHz demonstrated) with <span class="hlt">electron</span> beam currents up to 200 A at voltages up to 120 kV demonstrated. The design and performance of the PCE gun, along with several models used to predict and scale the performance, are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22303618','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22303618"><span id="translatedtitle">Anomalous skin effects in a weakly magnetized degenerate <span class="hlt">electron</span> <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Abbas, G. Sarfraz, M.; Shah, H. A.</p> <p>2014-09-15</p> <p>Fully relativistic analysis of anomalous skin effects for parallel propagating waves in a weakly magnetized degenerate <span class="hlt">electron</span> <span class="hlt">plasma</span> is presented and a graphical comparison is made with the results obtained using relativistic Maxwellian distribution function [G. Abbas, M. F. Bashir, and G. Murtaza, Phys. <span class="hlt">Plasmas</span> 18, 102115 (2011)]. It is found that the penetration depth for R- and L-waves for degenerate case is qualitatively small in comparison with the Maxwellian <span class="hlt">plasma</span> case. The quantitative reduction due to weak magnetic field in the skin depth in R-wave for degenerate <span class="hlt">plasma</span> is large as compared to the non-degenerate one. By ignoring the ambient magnetic field, previous results for degenerate field free case are salvaged [A. F. Alexandrov, A. S. Bogdankevich, and A. A. Rukhadze, Principles of <span class="hlt">Plasma</span> Electrodynamics (Springer-Verlag, Berlin/Heidelberg, 1984), p. 90].</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhPl...21i2108A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhPl...21i2108A"><span id="translatedtitle">Anomalous skin effects in a weakly magnetized degenerate <span class="hlt">electron</span> <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Abbas, G.; Sarfraz, M.; Shah, H. A.</p> <p>2014-09-01</p> <p>Fully relativistic analysis of anomalous skin effects for parallel propagating waves in a weakly magnetized degenerate <span class="hlt">electron</span> <span class="hlt">plasma</span> is presented and a graphical comparison is made with the results obtained using relativistic Maxwellian distribution function [G. Abbas, M. F. Bashir, and G. Murtaza, Phys. <span class="hlt">Plasmas</span> 18, 102115 (2011)]. It is found that the penetration depth for R- and L-waves for degenerate case is qualitatively small in comparison with the Maxwellian <span class="hlt">plasma</span> case. The quantitative reduction due to weak magnetic field in the skin depth in R-wave for degenerate <span class="hlt">plasma</span> is large as compared to the non-degenerate one. By ignoring the ambient magnetic field, previous results for degenerate field free case are salvaged [A. F. Alexandrov, A. S. Bogdankevich, and A. A. Rukhadze, Principles of <span class="hlt">Plasma</span> Electrodynamics (Springer-Verlag, Berlin/Heidelberg, 1984), p. 90].</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhPl...22k2118S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhPl...22k2118S"><span id="translatedtitle">Two-dimensional studies of relativistic <span class="hlt">electron</span> beam <span class="hlt">plasma</span> instabilities in an inhomogeneous <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shukla, Chandrasekhar; Das, Amita; Patel, Kartik</p> <p>2015-11-01</p> <p>Relativistic <span class="hlt">electron</span> beam propagation in <span class="hlt">plasma</span> is fraught with several micro instabilities like two stream, filamentation, etc., in <span class="hlt">plasma</span>. This results in severe limitation of the <span class="hlt">electron</span> transport through a <span class="hlt">plasma</span> medium. Recently, however, there has been an experimental demonstration of improved transport of Mega Ampere of <span class="hlt">electron</span> currents (generated by the interaction of intense laser with solid target) in a carbon nanotube structured solid target [G. Chatterjee et al., Phys. Rev. Lett. 108, 235005 (2012)]. This then suggests that the inhomogeneous <span class="hlt">plasma</span> (created by the ionization of carbon nanotube structured target) helps in containing the growth of the beam <span class="hlt">plasma</span> instabilities. This manuscript addresses this issue with the help of a detailed analytical study and 2-D Particle-In-Cell simulations. The study conclusively demonstrates that the growth rate of the dominant instability in the 2-D geometry decreases when the <span class="hlt">plasma</span> density is chosen to be inhomogeneous, provided the scale length 1/ks of the inhomogeneous <span class="hlt">plasma</span> is less than the typical <span class="hlt">plasma</span> skin depth (c/?0) scale. At such small scale lengths channelization of currents is also observed in simulation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19800046372&hterms=Haber+process&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D%2528Haber%2Bprocess%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19800046372&hterms=Haber+process&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D%2528Haber%2Bprocess%2529"><span id="translatedtitle">Strongly turbulent stabilization of <span class="hlt">electron</span> beam-<span class="hlt">plasma</span> interactions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Freund, H. P.; Haber, I.; Palmadesso, P.; Papadopoulos, K.</p> <p>1980-01-01</p> <p>The stabilization of <span class="hlt">electron</span> beam interactions due to strongly turbulent nonlinearities is studied analytically and numerically for a wide range of <span class="hlt">plasma</span> parameters. A fluid mode coupling code is described in which the effects of <span class="hlt">electron</span> and ion Landau damping and linear growth due to the energetic <span class="hlt">electron</span> beam are included in a phenomenological manner. Stabilization of the instability is found to occur when the amplitudes of the unstable modes exceed the threshold of the oscillating two-stream instability. The coordinate space structure of the turbulent spectrum which results clearly shows that soliton-like structures are formed by this process. Phenomenological models of both the initial stabilization and the asymptotic states are developed. Scaling laws between the beam-<span class="hlt">plasma</span> growth rate and the fluctuations in the fields and <span class="hlt">plasma</span> density are found in both cases, and shown to be in good agreement with the results of the simulation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AIPC.1693g0007S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AIPC.1693g0007S"><span id="translatedtitle">On thermalization of <span class="hlt">electron</span>-positron-photon <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Siutsou, I. A.; Aksenov, A. G.; Vereshchagin, G. V.</p> <p>2015-12-01</p> <p>Recently a progress has been made in understanding thermalization mechanism of relativistic <span class="hlt">plasma</span> starting from a non-equilibrium state. Relativistic Boltzmann equations were solved numerically for homogeneous isotropic <span class="hlt">plasma</span> with collision integrals for two- and three-particle interactions calculated from the first principles by means of QED matrix elements. All particles were assumed to fulfill Boltzmann statistics. In this work we follow <span class="hlt">plasma</span> thermalization by accounting for Bose enhancement and Pauli blocking in particle interactions. Our results show that particle in equilibrium reach Bose-Einstein distribution for photons, and Fermi-Dirac one for <span class="hlt">electrons</span>, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17931024','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17931024"><span id="translatedtitle">Nonlinear interactions between electromagnetic waves and <span class="hlt">electron</span> <span class="hlt">plasma</span> oscillations in quantum <span class="hlt">plasmas</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shukla, P K; Eliasson, B</p> <p>2007-08-31</p> <p>We consider nonlinear interactions between intense circularly polarized electromagnetic (CPEM) waves and <span class="hlt">electron</span> <span class="hlt">plasma</span> oscillations (EPOs) in a dense quantum <span class="hlt">plasma</span>, taking into account the <span class="hlt">electron</span> density response in the presence of the relativistic ponderomotive force and mass increase in the CPEM wave fields. The dynamics of the CPEM waves and EPOs is governed by the two coupled nonlinear Schrdinger equations and Poisson's equation. The nonlinear equations admit the modulational instability of an intense CPEM pump wave against EPOs, leading to the formation and trapping of localized CPEM wave pipes in the <span class="hlt">electron</span> density hole that is associated with a positive potential distribution in our dense <span class="hlt">plasma</span>. The relevance of our investigation to the next generation intense laser-solid density <span class="hlt">plasma</span> interaction experiments is discussed. PMID:17931024</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JPhCS.552a2014D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JPhCS.552a2014D"><span id="translatedtitle">Effect of <span class="hlt">electron</span> extraction from a grid <span class="hlt">plasma</span> cathode on the generation of emission <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Devyatkov, V. N.; Koval, N. N.</p> <p>2014-11-01</p> <p>The paper describes the operating mode of a <span class="hlt">plasma</span> <span class="hlt">electron</span> source based on a low- pressure arc discharge with grid stabilization of the <span class="hlt">plasma</span> emission boundary which provides a considerable (up to twofold) increase in discharge and beam currents at an Ar pressure in the vacuum chamber p = 0.02-0.05 Pa, accelerating voltages of up to U = 10 kV, and longitudinal magnetic field of up to Bz = 0.1 T. The discharge and beam currents are increased on <span class="hlt">electron</span> extraction from the emission <span class="hlt">plasma</span> through meshes of a fine metal grid due to the energy of a high-voltage power supply which ensures <span class="hlt">electron</span> emission and acceleration. The <span class="hlt">electron</span> emission from the <span class="hlt">plasma</span> cathode and arrival of ions from the acceleration gap in the discharge changes the discharge <span class="hlt">plasma</span> parameters near the emission grid, thus changing the potential of the emission grid electrode with respect to the discharge cathode. The load is not typical and changes the voltage polarity of the electrode gap connected to the discharge power supply, which is to be taken into account in its calculation and design. The effect of <span class="hlt">electron</span> emission from the <span class="hlt">plasma</span> cathode on the discharge system can not only change the discharge and beam current pulse shapes but can also lead to a breakdown of the acceleration gap and failure of semiconductor elements in the discharge power supply unit.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PPCF...57h5007H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PPCF...57h5007H"><span id="translatedtitle"><span class="hlt">Plasma</span> effects on the free-<span class="hlt">electron</span> laser gain with a <span class="hlt">plasma</span> wave undulator</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hedayati, R.; Jafari, S.; Batebi, S.</p> <p>2015-08-01</p> <p>Employing a magnetized <span class="hlt">plasma</span> medium in the interaction region of a free-<span class="hlt">electron</span> laser (FEL) offers the possibility of generating short wavelengths using moderate energy beams. <span class="hlt">Plasma</span> in the presence of static magnetic field supports right and left circularly polarized electromagnetic modes. By superposition of these two modes, a linearly polarized electromagnetic mode is generated which can be employed as a <span class="hlt">plasma</span> undulator in a FEL. This configuration has a higher tunability by controlling the <span class="hlt">plasma</span> density on top of the ? -tubability of the conventional FELs. The roles of the axial magnetic field and <span class="hlt">plasma</span> on the laser gain and the <span class="hlt">electron</span> trajectories of an e-beam propagating through the <span class="hlt">plasma</span> medium have been studied and new orbits of group (I, II, and III) have been found. Moreover, the stability of these orbits for different values of <span class="hlt">plasma</span> frequencies has been investigated. It is shown that by increasing the axial guide magnetic field strength, the gain for orbits of group I trivially increase, while a decrease in gain has been obtained for orbits of group II and group III. In addition, it is found that with increasing the <span class="hlt">plasma</span> frequency (or <span class="hlt">plasma</span> density) the gain for orbits of group I and group II trivially decreases and shift to the lower cyclotron frequencies, while an increase in gain has been obtained for orbits of group III.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..DPPBO4003R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..DPPBO4003R"><span id="translatedtitle">Thermal effects on the <span class="hlt">electron</span> density fluctuations in ICF <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rozmus, Wojciech; Chapman, T.; Berger, R.; Brantov, A.; Bychenkov, V.; Tzoufras, M.</p> <p>2013-10-01</p> <p>We have examined modifications of the <span class="hlt">electron</span> distribution functions (EDF) due to thermal gradients in the ignition-scale ICF <span class="hlt">plasmas</span>. In particular, given the high background temperatures of such <span class="hlt">plasmas</span> the heat-carrying <span class="hlt">electrons</span> have energies (20 - 40 keV) that are close to kinetic energies of the <span class="hlt">electrons</span> that are resonant with Langmuir waves produced by parametric instabilities, such as stimulated Raman scattering. We have found that under these conditions the modifications of the EDF introduce anisotropy in the <span class="hlt">plasma</span> response that manifests itself in the significant reduction (increase) of the Landau damping of Langmuir waves propagating along (against) the temperature gradient. Similarly there is strong anisotropy in the fluctuation spectra of the <span class="hlt">electron</span> <span class="hlt">plasma</span> waves that modifies Thomson scattering cross-section. The EDF have been calculated and compared using the standard Spitzer-Harm theory, numerical solutions to the Fokker-Planck equations and analytical solutions of the kinetic equation. An impact of this theory on the observations of scattering instabilities and Thomson scattering experiments in ICF <span class="hlt">plasmas</span> will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22224163','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22224163"><span id="translatedtitle">Influence of <span class="hlt">electron</span> injection into 27 cm audio <span class="hlt">plasma</span> cell on the <span class="hlt">plasma</span> diagnostics</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Haleem, N. A.; Ragheb, M. S.; Zakhary, S. G.; El Fiki, S. A.; Nouh, S. A.; El Disoki, T. M.</p> <p>2013-08-15</p> <p>In this article, the <span class="hlt">plasma</span> is created in a Pyrex tube (L = 27 cm, φ= 4 cm) as a single cell, by a capacitive audio frequency (AF) discharge (f = 10–100 kHz), at a definite pressure of ∼0.2 Torr. A couple of tube linear and deviating arrangements show <span class="hlt">plasma</span> characteristic conformity. The applied AF <span class="hlt">plasma</span> and the injection of <span class="hlt">electrons</span> into two gas mediums Ar and N{sub 2} revealed the increase of <span class="hlt">electron</span> density at distinct tube regions by one order to attain 10{sup 13}/cm{sup 3}. The <span class="hlt">electrons</span> temperature and density strengths are in contrast to each other. While their distributions differ along the <span class="hlt">plasma</span> tube length, they show a decaying sinusoidal shape where their peaks position varies by the gas type. The <span class="hlt">electrons</span> injection moderates <span class="hlt">electron</span> temperature and expands their density. The later highest peak holds for the N{sub 2} gas, at <span class="hlt">electrons</span> injection it changes to hold for the Ar. The sinusoidal decaying density behavior generates electric fields depending on the gas used and independent of tube geometry. The effect of the injected <span class="hlt">electrons</span> performs a responsive impact on <span class="hlt">electrons</span> density not attributed to the gas discharge. Analytical tools investigate the interaction of the <span class="hlt">plasma</span>, the discharge current, and the gas used on the electrodes. It points to the emigration of atoms from each one but for greater majority they behave to a preferred direction. Meanwhile, only in the linear regime, small percentage of atoms still moves in reverse direction. Traces of gas atoms revealed on both electrodes due to sheath regions denote lack of their participation in the discharge current. In addition, atoms travel from one electrode to the other by overcoming the sheaths regions occurring transportation of particles agglomeration from one electrode to the other. The <span class="hlt">electrons</span> injection has contributed to increase the <span class="hlt">plasma</span> <span class="hlt">electron</span> density peaks. These <span class="hlt">electrons</span> populations have raised the generated electrostatic fields assisting the elemental ions emigration to a preferred electrode direction. Regardless of <span class="hlt">plasma</span> electrodes positions and <span class="hlt">plasma</span> shape, ions can be departed from one electrode to deposit on the other one. In consequence, as an application the AF <span class="hlt">plasma</span> type can enhance the metal deposition from one electrode to the other.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013RScI...84h3301H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013RScI...84h3301H"><span id="translatedtitle">Influence of <span class="hlt">electron</span> injection into 27 cm audio <span class="hlt">plasma</span> cell on the <span class="hlt">plasma</span> diagnostics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Haleem, N. A.; El Fiki, S. A.; Nouh, S. A.; El Disoki, T. M.; Ragheb, M. S.; Zakhary, S. G.</p> <p>2013-08-01</p> <p>In this article, the <span class="hlt">plasma</span> is created in a Pyrex tube (L = 27 cm, ? = 4 cm) as a single cell, by a capacitive audio frequency (AF) discharge (f = 10-100 kHz), at a definite pressure of 0.2 Torr. A couple of tube linear and deviating arrangements show <span class="hlt">plasma</span> characteristic conformity. The applied AF <span class="hlt">plasma</span> and the injection of <span class="hlt">electrons</span> into two gas mediums Ar and N2 revealed the increase of <span class="hlt">electron</span> density at distinct tube regions by one order to attain 1013/cm3. The <span class="hlt">electrons</span> temperature and density strengths are in contrast to each other. While their distributions differ along the <span class="hlt">plasma</span> tube length, they show a decaying sinusoidal shape where their peaks position varies by the gas type. The <span class="hlt">electrons</span> injection moderates <span class="hlt">electron</span> temperature and expands their density. The later highest peak holds for the N2 gas, at <span class="hlt">electrons</span> injection it changes to hold for the Ar. The sinusoidal decaying density behavior generates electric fields depending on the gas used and independent of tube geometry. The effect of the injected <span class="hlt">electrons</span> performs a responsive impact on <span class="hlt">electrons</span> density not attributed to the gas discharge. Analytical tools investigate the interaction of the <span class="hlt">plasma</span>, the discharge current, and the gas used on the electrodes. It points to the emigration of atoms from each one but for greater majority they behave to a preferred direction. Meanwhile, only in the linear regime, small percentage of atoms still moves in reverse direction. Traces of gas atoms revealed on both electrodes due to sheath regions denote lack of their participation in the discharge current. In addition, atoms travel from one electrode to the other by overcoming the sheaths regions occurring transportation of particles agglomeration from one electrode to the other. The <span class="hlt">electrons</span> injection has contributed to increase the <span class="hlt">plasma</span> <span class="hlt">electron</span> density peaks. These <span class="hlt">electrons</span> populations have raised the generated electrostatic fields assisting the elemental ions emigration to a preferred electrode direction. Regardless of <span class="hlt">plasma</span> electrodes positions and <span class="hlt">plasma</span> shape, ions can be departed from one electrode to deposit on the other one. In consequence, as an application the AF <span class="hlt">plasma</span> type can enhance the metal deposition from one electrode to the other.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApSS..364..181M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApSS..364..181M"><span id="translatedtitle">Modulating <span class="hlt">electronic</span>, magnetic and chemical properties of MoS2 monolayer <span class="hlt">sheets</span> by substitutional doping with transition metals</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ma, Dongwei; Ju, Weiwei; Li, Tingxian; Zhang, Xiwei; He, Chaozheng; Ma, Benyuan; Tang, Yanan; Lu, Zhansheng; Yang, Zongxian</p> <p>2016-02-01</p> <p>Based on first-principles calculations, the effects of substitutional doping with transition-metal (TM) atoms (Co, Ni, Ru, Rh, Pd, Ir, Pt and Au) were investigated on the <span class="hlt">electronic</span> structure, magnetic property and chemical activity of the molybdenum disulfide (MoS2) monolayer <span class="hlt">sheet</span>. It is found that all the considered TM atoms are strongly bonded to the sulfur defects. The magnetic properties of MoS2 monolayer <span class="hlt">sheets</span> can be modulated by embedding TM atoms. The introduced spin magnetic moments are 1.00, 1.00, 1.00, 0.99, and 2.00μB, respectively, for Ir, Rh, Co, Au and Ru doping. The <span class="hlt">electronic</span> properties of MoS2 monolayer <span class="hlt">sheets</span> are also significantly changed due to the induced impurity states in the band gap. The chemical activity of the TM-doped MoS2 monolayer <span class="hlt">sheet</span> (TM-MoS2) is significantly enhanced compared with the undoped <span class="hlt">sheet</span>. Most TM-MoS2 can strongly adsorb and thus effectively activate the adsorbed O2. It is proposed that the partially occupied d orbitals of the doped TM atoms localized in the vicinity of the Fermi level play a crucial role in adsorbing and activating the adsorbed O2. The adsorption of O2 can in turn modify the <span class="hlt">electronic</span> structures and magnetic properties of TM-MoS2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6520065','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6520065"><span id="translatedtitle">Inelastic <span class="hlt">electron</span>-ion scattering in a dense <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hatton, G.J.; Lane, N.F.; Weisheit, J.C.</p> <p>1981-04-01</p> <p>The Born approximation was used to investigate the influence of a dense <span class="hlt">plasma</span> on the inelastic scattering of <span class="hlt">electrons</span> by one-<span class="hlt">electron</span> ions. Scaled collision strengths Z/sup 2/Q for 1s ..-->.. 2s, 1s ..-->.. 2p and 2s ..-->.. 2p transitions in an ion of arbitrary nuclear charge Z were computed for a Debye-Hueckel model of the screened Coulomb interaction. Over a wide range of screening lengths, the effect of the <span class="hlt">plasma</span> environment is to appreciably reduce cross sections just above threshold.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20093738','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20093738"><span id="translatedtitle"><span class="hlt">Plasma</span> membrane <span class="hlt">electron</span> transport in frog blood vessels.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rao, Rashmi P; Nalini, K; Rao, J Prakasa</p> <p>2009-12-01</p> <p>In an attempt to see if frog blood vessels possess a <span class="hlt">plasma</span> membrane <span class="hlt">electron</span> transport system, the postcaval vein and aorta isolated from Rana tigrina were tested for their ability to reduce ferricyanide, methylene blue, and 2,6-dichloroindophenol. While the dyes remained unchanged, ferricyanide was reduced to ferrocyanide. This reduction was resistant to inhibition by cyanide and azide. Heptane extraction or formalin fixation of the tissues markedly reduced the capability to reduce ferricyanide. Denuded aortas retained only 30% of the activity of intact tissue. Our results indicate that the amphibian postcaval vein and aorta exhibit <span class="hlt">plasma</span> membrane <span class="hlt">electron</span> transport. PMID:20093738</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5631171','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5631171"><span id="translatedtitle">High-frequency microinstabilities in hot-<span class="hlt">electron</span> <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chen, Y.J.; Nevins, W.M.; Smith, G.R.</p> <p>1981-11-24</p> <p>Instabilities with frequencies in the neighborhood of the <span class="hlt">electron</span> cyclotron frequency are of interest in determining stable operating regimes of hot-<span class="hlt">electron</span> <span class="hlt">plasmas</span> in EBT devices and in tandem mirrors. Previous work used model distributions significantly different than those suggested by recent Fokker-Planck studies. We use much more realistic model distributions in a computer code that solves the full electromagnetic dispersion relation governing longitudinal and transverse waves in a uniform <span class="hlt">plasma</span>. We allow for an arbitrary direction of wave propagation. Results for the whistler and upper-hybrid loss-cone instabilities are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AdSpR..54.1786E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AdSpR..54.1786E"><span id="translatedtitle">Nonlinear <span class="hlt">electron</span>-acoustic rogue waves in <span class="hlt">electron</span>-beam <span class="hlt">plasma</span> system with non-thermal hot <span class="hlt">electrons</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Elwakil, S. A.; El-hanbaly, A. M.; Elgarayh, A.; El-Shewy, E. K.; Kassem, A. I.</p> <p>2014-11-01</p> <p>The properties of nonlinear <span class="hlt">electron</span>-acoustic rogue waves have been investigated in an unmagnetized collisionless four-component <span class="hlt">plasma</span> system consisting of a cold <span class="hlt">electron</span> fluid, non-thermal hot <span class="hlt">electrons</span> obeying a non-thermal distribution, an <span class="hlt">electron</span> beam and stationary ions. It is found that the basic set of fluid equations is reduced to a nonlinear Schrodinger equation. The dependence of rogue wave profiles on the <span class="hlt">electron</span> beam and energetic population parameter are discussed. The results of the present investigation may be applicable in auroral zone <span class="hlt">plasma</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSM23C4254Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSM23C4254Y"><span id="translatedtitle">Sudden Pressure Enhancement and Tailward Retreat in the Near-Earth <span class="hlt">Plasma</span> <span class="hlt">Sheet</span>: THEMIS Observation and MHD Simulation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yao, Y.; Ebihara, Y.; Tanaka, T.</p> <p>2014-12-01</p> <p>Sudden enhancement of the <span class="hlt">plasma</span> pressure in the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> is one of the common manifestations of the substorms, and is thought to play an important role in relevant disturbances in the magnetosphere and ionosphere. On 1 March 2008 four of the THEMIS (Time History of Events and Macroscale Interactions during Substorms) probes observed the sudden enhancement of the <span class="hlt">plasma</span> pressure around 15:40 UT. The four probes were almost aligned along the Sun-Earth line, which was suitable for investigating spatial-temporal evolution of the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> around the substorm onset. The four probes were located off the equatorial plane, according to a magnetic field model. The <span class="hlt">plasma</span> pressure suddenly increased at the inner most probe first (at ~7.2 Re), followed by the outer probes (at ~7.5, ~8.3, and ~10.4 Re), that could be seen as a tailward propagation (or retreat) of high-pressure region (HPR). After comparing with results of a global magnetohydrodynamics (MHD) simulation, we found that only the tailward propagation of the HPR could be seen at off-equator. Near the equatorial plane, the HPR propagates earthward from the magnetotail region, then it retreats tailward. In the course of the tailward propagation, the HPR also propagates away from the equatorial plane. As a consequence, the inner most probe observed the pressure enhancement first, followed by the outer probes. The propagation of the HPR in the ZGSM direction is understood to be a combination of the convergence of the <span class="hlt">plasma</span> flow (the divergence of bulk velocity along the ZGSM axis), and the pressure gradient force.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120..201Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120..201Y"><span id="translatedtitle">Sudden pressure enhancement and tailward retreat in the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span>: THEMIS observation and MHD simulation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yao, Y.; Ebihara, Y.; Tanaka, T.</p> <p>2015-01-01</p> <p>enhancement of the <span class="hlt">plasma</span> pressure in the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> is one of the common manifestations of substorms and is thought to play an important role in relevant disturbances in the magnetosphere and ionosphere. On 1 March 2008, four of the Time History of Events and Macroscale Interactions during Substorms probes observed the sudden enhancement of the <span class="hlt">plasma</span> pressure around 15:40 UT. The four probes were almost aligned along the Sun-Earth line, which was suitable for investigating spatial-temporal evolution of the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> around the substorm onset. The four probes were located off the equatorial plane, according to a magnetic field model. The <span class="hlt">plasma</span> pressure suddenly increased at the innermost probe first (at ~7.2 Re), followed by the outer probes (at ~7.5, ~8.3, and ~10.4 Re), that could be seen as a tailward propagation (or retreat) of high-pressure region (HPR). After comparing with results of a global magnetohydrodynamic simulation, we found that only the tailward propagation of the HPR could be seen at off equator. Near the equatorial plane, the HPR propagates earthward from the magnetotail region, then it retreats tailward. In the course of the tailward retreat, the HPR also propagates away from the equatorial plane. As a consequence, the innermost probe observed the pressure enhancement first, followed by the outer probes. The propagation of the HPR in the ZGSM direction is understood to be a combination of the convergence of the <span class="hlt">plasma</span> flow (the divergence of bulk velocity along the ZGSM axis) and the pressure gradient force.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22227984','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22227984"><span id="translatedtitle">Influence of <span class="hlt">electron</span> evaporative cooling on ultracold <span class="hlt">plasma</span> expansion</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wilson, Truman; Chen, Wei-Ting; Roberts, Jacob</p> <p>2013-07-15</p> <p>The expansion of ultracold neutral <span class="hlt">plasmas</span> (UCP) is driven primarily by the thermal pressure of the <span class="hlt">electron</span> component and is therefore sensitive to the <span class="hlt">electron</span> temperature. For typical UCP spatial extents, evaporative cooling has a significant influence on the UCP expansion rate at lower densities (less than 10{sup 8}/cm{sup 3}). We studied the effect of <span class="hlt">electron</span> evaporation in this density range. Owing to the low density, the effects of three-body recombination were negligible. We modeled the expansion by taking into account the change in <span class="hlt">electron</span> temperature owing to evaporation as well as adiabatic expansion and found good agreement with our data. We also developed a simple model for initial evaporation over a range of ultracold <span class="hlt">plasma</span> densities, sizes, and <span class="hlt">electron</span> temperatures to determine over what parameter range <span class="hlt">electron</span> evaporation is expected to have a significant effect. We also report on a signal calibration technique, which relates the signal at our detector to the total number of ions and <span class="hlt">electrons</span> in the ultracold <span class="hlt">plasma</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014Ap%26SS.352..185P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014Ap%26SS.352..185P"><span id="translatedtitle">Time evolution of nonplanar <span class="hlt">electron</span> acoustic shock waves in a <span class="hlt">plasma</span> with superthermal <span class="hlt">electrons</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pakzad, Hamid Reza; Javidan, Kurosh; Tribeche, Mouloud</p> <p>2014-07-01</p> <p>The propagation of cylindrical and spherical <span class="hlt">electron</span> acoustic (EA) shock waves in unmagnetized <span class="hlt">plasmas</span> consisting of cold fluid <span class="hlt">electrons</span>, hot <span class="hlt">electrons</span> obeying a superthermal distribution and stationary ions, has been investigated. The standard reductive perturbation method (RPM) has been employed to derive the cylindrical/spherical Korteweg-de-Vries-Burger (KdVB) equation which governs the dynamics of the EA shock structures. The effects of nonplanar geometry, <span class="hlt">plasma</span> kinematic viscosity and <span class="hlt">electron</span> suprathermality on the temporal evolution of the cylindrical and spherical EA shock waves are numerically examined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..GECKW1005N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..GECKW1005N"><span id="translatedtitle"><span class="hlt">Electron</span> Density Measurement of Argon Containing <span class="hlt">Plasmas</span> by Saturation Spectroscopy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nishiyama, S.; Wang, H.; Tomioka, S.; Sasaki, K.</p> <p>2014-10-01</p> <p>Langmuir probes are widely used for <span class="hlt">electron</span> density measurements in <span class="hlt">plasmas</span>. However, the use of a conventional probe should be avoided in a <span class="hlt">plasma</span> which needs high purity because of the possibility of contamination. Optical measurements are suitable for these <span class="hlt">plasmas</span>. In this work, we applied saturation spectroscopy to the <span class="hlt">electron</span> density measurement. The peak height of the saturation spectrum is affected by the relaxation frequency of the related energy levels. In the case of the metastable levels of argon, the <span class="hlt">electron</span> impact quenching rate, which is proportional to the <span class="hlt">electron</span> density, is the dominant factor. In our experiments, an inductively coupled <span class="hlt">plasma</span> source and a tunable cw diode laser were used. The frequency of the laser was scanned over the Doppler width of the 4 s[3/ 2 ] 2 o - 4 p[ 3 / 2 ] 2 (763.51 nm) transition. The experimental saturation spectrum was composed of a sharp Lorentzian peak and a broad base component, which was caused by velocity changing collisions. We deduced a new relationship between the saturation parameter and the measured saturated absorption spectrum with considering velocity changing collisions. We confirmed a linear relationship, which was expected theoretically, between the inverse of the saturation parameter and the <span class="hlt">electron</span> density. Part of this work is supported by JSPS KAKENHI Grant Number 24540529.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20860240','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20860240"><span id="translatedtitle">Nonlocal <span class="hlt">electron</span> transport in magnetized <span class="hlt">plasmas</span> with arbitrary atomic number</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bennaceur-Doumaz, D.; Bendib, A.</p> <p>2006-09-15</p> <p>The numerical solution of the steady-state <span class="hlt">electron</span> Fokker-Planck equation perturbed with respect to a global equilibrium is presented in magnetized <span class="hlt">plasmas</span> with arbitrary atomic number Z. The magnetic field is assumed to be constant and the <span class="hlt">electron-electron</span> collisions are described by the Landau collision operator. The solution is derived in the Fourier space and in the framework of the diffusive approximation which captures the spatial nonlocal effects. The transport coefficients are deduced and used to close a complete set of nonlocal <span class="hlt">electron</span> fluid equations. This work improves the results of A. Bendib et al. [Phys. <span class="hlt">Plasmas</span> 9, 1555 (2002)] and of A. V. Brantov et al. [Phys. <span class="hlt">Plasmas</span> 10, 4633 (2003)] restricted to the local and nonlocal high-Z <span class="hlt">plasma</span> approximations, respectively. The influence of the magnetic field on the nonlocal effects is discussed. We propose also accurate numerical fits of the relevant transport coefficients with respect to the collisionality parameter {lambda}{sub ei}/L and the atomic number Z, where L is the typical scale length and {lambda}{sub ei} is the <span class="hlt">electron</span>-ion mean-free-path.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20192326','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20192326"><span id="translatedtitle">Glow <span class="hlt">plasma</span> trigger for <span class="hlt">electron</span> cyclotron resonance ion sources.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vodopianov, A V; Golubev, S V; Izotov, I V; Nikolaev, A G; Oks, E M; Savkin, K P; Yushkov, G Yu</p> <p>2010-02-01</p> <p><span class="hlt">Electron</span> cyclotron resonance ion sources (ECRISs) are particularly useful for nuclear, atomic, and high energy physics, as unique high current generators of multicharged ion beams. <span class="hlt">Plasmas</span> of gas discharges in an open magnetic trap heated by pulsed (100 micros and longer) high power (100 kW and higher) high-frequency (greater than 37.5 GHz) microwaves of gyrotrons is promising in the field of research in the development of <span class="hlt">electron</span> cyclotron resonance sources for high charge state ion beams. Reaching high ion charge states requires a decrease in gas pressure in the magnetic trap, but this method leads to increases in time, in which the microwave discharge develops. The gas breakdown and microwave discharge duration becomes greater than or equal to the microwave pulse duration when the pressure is decreased. This makes reaching the critical <span class="hlt">plasma</span> density initiate an <span class="hlt">electron</span> cyclotron resonance (ECR) discharge during pulse of microwave gyrotron radiation with gas pressure lower than a certain threshold. In order to reduce losses of microwave power, it is necessary to shorten the time of development of the ECR discharge. For fast triggering of ECR discharge under low pressure in an ECRIS, we initially propose to fill the magnetic trap with the <span class="hlt">plasmas</span> of auxiliary pulsed discharges in crossed ExB fields. The glow <span class="hlt">plasma</span> trigger of ECR based on a Penning or magnetron discharge has made it possible not only to fill the trap with <span class="hlt">plasma</span> with density of 10(12) cm(-3), required for a rapid increase in <span class="hlt">plasma</span> density and finally for ECR discharge ignition, but also to initially heat the <span class="hlt">plasma</span> <span class="hlt">electrons</span> to T(e) approximately = 20 eV. PMID:20192326</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhPl...22i2512M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhPl...22i2512M"><span id="translatedtitle">Runaway <span class="hlt">electron</span> dynamics in tokamak <span class="hlt">plasmas</span> with high impurity content</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Martn-Sols, J. R.; Loarte, A.; Lehnen, M.</p> <p>2015-09-01</p> <p>The dynamics of high energy runaway <span class="hlt">electrons</span> is analyzed for <span class="hlt">plasmas</span> with high impurity content. It is shown that modified collision terms are required in order to account for the collisions of the relativistic runaway <span class="hlt">electrons</span> with partially stripped impurity ions, including the effect of the collisions with free and bound <span class="hlt">electrons</span>, as well as the scattering by the full nuclear and the <span class="hlt">electron</span>-shielded ion charge. The effect of the impurities on the avalanche runaway growth rate is discussed. The results are applied, for illustration, to the interpretation of the runaway <span class="hlt">electron</span> behavior during disruptions, where large amounts of impurities are expected, particularly during disruption mitigation by massive gas injection. The consequences for the <span class="hlt">electron</span> synchrotron radiation losses and the resulting runaway <span class="hlt">electron</span> dynamics are also analyzed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19830052978&hterms=electron+beam+atmosphere&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Delectron%2Bbeam%2Batmosphere','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19830052978&hterms=electron+beam+atmosphere&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Delectron%2Bbeam%2Batmosphere"><span id="translatedtitle"><span class="hlt">Electron</span> energy distribution produced by beam-<span class="hlt">plasma</span> discharge</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Anderson, H. R.; Gordeuk, J.; Jost, R. J.</p> <p>1982-01-01</p> <p>In an investigation of a beam-<span class="hlt">plasma</span> discharge (BPD), the <span class="hlt">electron</span> energy distribution of an <span class="hlt">electron</span> beam moving through a partially ionized gas is analyzed. Among other results, it is found that the occurrence of BPD heats the initially cold <span class="hlt">electron</span> beam from the accelerator. The directional intensity of <span class="hlt">electrons</span> measured outside the beam core indicates that most particles suffer a single scattering in energy and pitch angle. At low currents this result is expected as beam particles collide with the neutral atmosphere, while in BPD the majority of particles is determined to still undergo a single scattering near the original beam core. The extended energy spectra at various beam currents show two rather distinct <span class="hlt">plasma</span> populations, one centered at the initial beam energy (approximately 1500 eV) and the other at approximately 150 eV.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22408130','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22408130"><span id="translatedtitle">Beltrami–Bernoulli equilibria in <span class="hlt">plasmas</span> with degenerate <span class="hlt">electrons</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Berezhiani, V. I.; Shatashvili, N. L.; Mahajan, S. M.</p> <p>2015-02-15</p> <p>A new class of Double Beltrami–Bernoulli equilibria, sustained by <span class="hlt">electron</span> degeneracy pressure, is investigated. It is shown that due to <span class="hlt">electron</span> degeneracy, a nontrivial Beltrami–Bernoulli equilibrium state is possible even for a zero temperature <span class="hlt">plasma</span>. These states are, conceptually, studied to show the existence of new energy transformation pathways converting, for instance, the degeneracy energy into fluid kinetic energy. Such states may be of relevance to compact astrophysical objects like white dwarfs, neutron stars, etc.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850036959&hterms=skew+distribution&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dskew%2Bdistribution','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850036959&hterms=skew+distribution&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dskew%2Bdistribution"><span id="translatedtitle"><span class="hlt">Electron</span> <span class="hlt">plasma</span> waves upstream of the earth's bow shock</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lacombe, C.; Mangeney, A.; Harvey, C. C.; Scudder, J. D.</p> <p>1985-01-01</p> <p>Electrostatic waves are observed around the <span class="hlt">plasma</span> frequency fpe in the <span class="hlt">electron</span> foreshock, together with <span class="hlt">electrons</span> backstreaming from the bow shock. Using data from the sounder aboard ISEE 1, it is shown that this noise, previously understood as narrow band Langmuir waves more or less widened by Doppler shift or nonlinear effects, is in fact composed of two distinct parts: one is a narrow band noise, emitted just above fpe, and observed at the upstream boundary of the <span class="hlt">electron</span> foreshock. This component has been interpreted as Langmuir waves emitted by a beam-<span class="hlt">plasma</span> instability. It is suggested that it is of sufficiently large amplitude and monochromatic enough to trap resonant <span class="hlt">electrons</span>. The other is a broad band noise, more impulsive than the narrow band noise, observed well above and/or well below fpe, deeper in the <span class="hlt">electron</span> foreshock. The broad band noise has an average spectrum with a typical bi-exponential shape; its peak frequency is not exactly equal to fpe and depends on the Deybe length. This peak frequency also depends on the velocity for which the <span class="hlt">electron</span> distribution has maximum skew. An experimental determination of the dispersion relation of the broad band noise shows that this noise, as well as the narrow band noise, may be due to the instability of a hot beam in a <span class="hlt">plasma</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010055260','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010055260"><span id="translatedtitle">Low Energy <span class="hlt">Electrons</span> in the Mars <span class="hlt">Plasma</span> Environment</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Link, Richard</p> <p>2001-01-01</p> <p>The ionosphere of Mars is rather poorly understood. The only direct measurements were performed by the Viking 1 and 2 landers in 1976, both of which carried a Retarding Potential Analyzer. The RPA was designed to measure ion properties during the descent, although <span class="hlt">electron</span> fluxes were estimated from changes in the ion currents. Using these derived low-energy <span class="hlt">electron</span> fluxes, Mantas and Hanson studied the photoelectron and the solar wind <span class="hlt">electron</span> interactions with the atmosphere and ionosphere of Mars. Unanswered questions remain regarding the origin of the low-energy <span class="hlt">electron</span> fluxes in the vicinity of the Mars <span class="hlt">plasma</span> boundary. Crider, in an analysis of Mars Global Surveyor Magnetometer/<span class="hlt">Electron</span> Reflectometer measurements, has attributed the formation of the magnetic pile-up boundary to <span class="hlt">electron</span> impact ionization of exospheric neutral species by solar wind <span class="hlt">electrons</span>. However, the role of photoelectrons escaping from the lower ionosphere was not determined. In the proposed work, we will examine the role of solar wind and ionospheric photoelectrons in producing ionization in the upper ionosphere of Mars. Low-energy (< 4 keV) <span class="hlt">electrons</span> will be modeled using the two-stream <span class="hlt">electron</span> transport code of Link. The code models both external (solar wind) and internal (photoelectron) sources of ionization, and accounts for Auger <span class="hlt">electron</span> production. The code will be used to analyze Mars Global Surveyor measurements of solar wind and photoelectrons down to altitudes below 200 km in the Mars ionosphere, in order to determine the relative roles of solar wind and escaping photoelectrons in maintaining <span class="hlt">plasma</span> densities in the region of the Mars <span class="hlt">plasma</span> boundary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21255213','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21255213"><span id="translatedtitle">Magnetically Controlled Optical <span class="hlt">Plasma</span> Waveguide for <span class="hlt">Electron</span> Acceleration</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pollock, B. B.; Davis, P.; Divol, L.; Glenzer, S. H.; Palastro, J. P.; Price, D.; Froula, D. H.; Tynan, G. R.</p> <p>2009-01-22</p> <p>In order to produce multi-Gev <span class="hlt">electrons</span> from Laser Wakefield Accelerators, we present a technique to guide high power laser beams through underdense <span class="hlt">plasma</span>. Experimental results from the Jupiter Laser Facility at the Lawrence Livermore National Laboratory that show density channels with minimum <span class="hlt">plasma</span> densities below 5x10{sup 17} cm{sup -3} are presented. These results are obtained using an external magnetic field (<5 T) to limit the radial heat flux from a pre-forming laser beam. The resulting increased <span class="hlt">plasma</span> pressure gradient produces a parabolic density gradient which is tunable by changing the external magnetic field strength. These results are compared with 1-D hydrodynamic simulations, while quasi-static kinetic simulations show that for these channel conditions 90% of the energy in a 150 TW short pulse beam is guided over 5 cm and predict <span class="hlt">electron</span> energy gains of 3 GeV.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20636635','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20636635"><span id="translatedtitle">Fizeau interferometer for measurement of <span class="hlt">plasma</span> <span class="hlt">electron</span> current</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Brower, D.L.; Ding, W.X.; Deng, B.H.; Mahdavi, M.A.; Mirnov, V.; Prager, S.C.</p> <p>2004-10-01</p> <p>A high-resolution, vertically viewing far-infrared polarimeter-interferometer system is currently used on the Madison symmetric torus (MST) reversed-field pinch (RFP) to measure the <span class="hlt">plasma</span> <span class="hlt">electron</span> density and toroidal current density via Faraday rotation. In this article, we propose a scheme to measure the well-known Fizeau effect, whereby through modest modification of the existing apparatus, the line-integrated poloidal current density can also be directly measured. This parameter is important, since the RFP toroidal magnetic field is largely determined by currents flowing within the <span class="hlt">plasma</span>. The Fizeau effect is a phase shift of an electromagnetic wave associated with movement of a dielectric medium. This motion can be related directly to the <span class="hlt">plasma</span> <span class="hlt">electron</span> current. Determining the Fizeau effect involves measurement of the phase shift between two collinear, orthogonally polarized, counterpropagating laser beams. Estimates indicate a phase shift of {approx}2 deg. is expected for typical MST parameters, well within the existing system resolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/945800','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/945800"><span id="translatedtitle">Magnetically Controlled Optical <span class="hlt">Plasma</span> Waveguide for <span class="hlt">Electron</span> Acceleration</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pollock, B B; Froula, D H; Tynan, G R; Divol, L; Davis, P; Palastro, J P; Price, D; Glenzer, S H</p> <p>2008-08-28</p> <p>In order to produce multi-Gev <span class="hlt">electrons</span> from Laser Wakefield Accelerators, we present a technique to guide high power laser beams through underdense <span class="hlt">plasma</span>. Experimental results from the Jupiter Laser Facility at the Lawrence Livermore National Laboratory that show density channels with minimum <span class="hlt">plasma</span> densities below 5 x 10{sup 17} cm{sup -3} are presented. These results are obtained using an external magnetic field (<5 T) to limit the radial heat flux from a pre-forming laser beam. The resulting increased <span class="hlt">plasma</span> pressure gradient produces a parabolic density gradient which is tunable by changing the external magnetic field strength. These results are compared with 1-D hydrodynamic simulations, while quasi-static kinetic simulations show that for these channel conditions 90% of the energy in a 150 TW short pulse beam is guided over 5 cm and predict <span class="hlt">electron</span> energy gains of 3 GeV.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19770032066&hterms=1055&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2526%25231055','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19770032066&hterms=1055&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2526%25231055"><span id="translatedtitle"><span class="hlt">Electron</span> impact excitation coefficients for laboratory and astrophysical <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Davis, J.; Kepple, P. C.; Blaha, M.</p> <p>1976-01-01</p> <p><span class="hlt">Electron</span> impact excitation rate coefficients have been obtained for a number of transitions in highly ionized ions of interest to astrophysical and laboratory <span class="hlt">plasmas</span>. The calculations were done using the method of distorted waves. Results are presented for various transitions in highly ionized Ne, Na, Al, Si, A, Ca, Ni and Fe.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1122866','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1122866"><span id="translatedtitle">Experimental Studies of Self Organization with <span class="hlt">Electron</span> <span class="hlt">Plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Matthaeus, William H.</p> <p>2011-04-11</p> <p>During the period of this grant we had a very active research effort in our group on the topic of 2D <span class="hlt">electron</span> <span class="hlt">plasmas</span>, relaxation, 2D Navier Stokes turbulence, and related issues. The project also motivated other studies we carried out such as a study of 2D turbulence with two-species vorticity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E2022M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E2022M"><span id="translatedtitle">Analytical theory of a current <span class="hlt">sheet</span> formed between the magnetized and nonmagnetized <span class="hlt">plasmas</span> with arbitrary energy distribution of particles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Martyanov, Vladimir; Kocharovsky, Vladimir; Kocharovsky, Vitaly</p> <p></p> <p>We present analytical description of a self-consistent stationary boundary layer formed between the magnetized and nonmagnetized collisionless <span class="hlt">plasmas</span> with arbitrary energy distribution of particles. Various spatial profiles of the current and respective particle distributions in the neutral current <span class="hlt">sheets</span> are found on the basis of the self-consistency equation of the Grad-Shafranov type, which takes into account a homogeneous external magnetic field. The solutions are obtained due to development of the method of invariants of particle motion (Astron. Lett. 36, 396 (2010)) and provide, for the first time, a detailed description of various transition domains in the magnetospheres of stars and planets, in particular, boundary regions formed by an interaction of a solar wind with an interstellar medium or Earth magnetosphere. We restrict ourselves to the shearless magnetic field configurations and consider four special dependencies of particle distribution function on momentum parallel to current direction, which make it possible to detail the relations between the magnetic field profile, <span class="hlt">plasma</span> density, and particle anisotropy gradient, including both thin and thick (with respect to a particle gyroradius) layers. Special attention is paid to the cases of an utmost sharp boundary between the magnetized and nonmagnetized <span class="hlt">plasmas</span> and to the cases where there are sections of a boundary current <span class="hlt">sheet</span> with magnetic field energy density exceeding kinetic energy density of <span class="hlt">plasma</span> particles. The kinetic instabilities and reconnection phenomena are also discussed, especially the ones related to the Weibel instability in the weakly magnetized parts of the boundary layer. These analytical results are applied to the analysis of the spacecraft observations of the magnetized-nonmagnetized boundaries in cosmic <span class="hlt">plasma</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JMMM..401..656B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JMMM..401..656B"><span id="translatedtitle"><span class="hlt">Electronic</span> and magnetic properties of monolayer SiC <span class="hlt">sheet</span> doped with 3d-transition metals</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bezi Javan, Masoud</p> <p>2016-03-01</p> <p>We theoretically studied the <span class="hlt">electronic</span> and magnetic properties of the monolayer SiC <span class="hlt">sheet</span> doped by 3d transition-metal (TM) atoms. The structural properties, induced strain, <span class="hlt">electronic</span> and magnetic properties were studied for cases that a carbon or silicon of the SiC <span class="hlt">sheet</span> replaced with TM atoms. We found that the mount of induced strain to the lattice structure of the SiC <span class="hlt">sheet</span> with substituting TM atoms is different for Si (TMSi) and C (TMC) sites as the TMSi structures have lower value of the strain. Also the TM atoms can be substituted in the lattice of the SiC <span class="hlt">sheet</span> with different binding energy values for TMSi and TMC structures as the TMSi structures have higher value of the binding energies. Dependent to the structural properties, the TM doped SiC <span class="hlt">sheets</span> show magnetic or nonmagnetic properties. We found that some structures such as MnSi, CuSi and CoC configurations have significant total magnetic moment about 3 μB.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24929924','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24929924"><span id="translatedtitle">Analysis of <span class="hlt">electron</span> beam damage of exfoliated MoS? <span class="hlt">sheets</span> and quantitative HAADF-STEM imaging.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Garcia, Alejandra; Raya, Andres M; Mariscal, Marcelo M; Esparza, Rodrigo; Herrera, Miriam; Molina, Sergio I; Scavello, Giovanni; Galindo, Pedro L; Jose-Yacaman, Miguel; Ponce, Arturo</p> <p>2014-11-01</p> <p>In this work we examined MoS? <span class="hlt">sheets</span> by aberration-corrected scanning transmission <span class="hlt">electron</span> microscopy (STEM) at three different energies: 80, 120 and 200 kV. Structural damage of the MoS? <span class="hlt">sheets</span> has been controlled at 80 kV according a theoretical calculation based on the inelastic scattering of the <span class="hlt">electrons</span> involved in the interaction <span class="hlt">electron</span>-matter. The threshold energy for the MoS? material has been found and experimentally verified in the microscope. At energies higher than the energy threshold we show surface and edge defects produced by the <span class="hlt">electron</span> beam irradiation. Quantitative analysis at atomic level in the images obtained at 80 kV has been performed using the experimental images and via STEM simulations using SICSTEM software to determine the exact number of MoS2? layers. PMID:24929924</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4169717','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4169717"><span id="translatedtitle">Analysis of <span class="hlt">electron</span> beam damage of exfoliated MoS2 <span class="hlt">sheets</span> and quantitative HAADF-STEM imaging</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Garcia, A.; Raya, A.M.; Mariscal, M.M.; Esparza, R.; Herrera, M.; Molina, S.I.; Scavello, G.; Galindo, P.L.; Jose-Yacaman, M.; Ponce, A.</p> <p>2014-01-01</p> <p>In this work we examined MoS2 <span class="hlt">sheets</span> by aberration-corrected scanning transmission <span class="hlt">electron</span> microscopy (STEM) at three different energies: 80, 120 and 200 kV. Structural damage of the MoS2 <span class="hlt">sheets</span> has been controlled at 80 kV according a theoretical calculation based on the inelastic scattering of the <span class="hlt">electrons</span> involved in the interaction <span class="hlt">electron</span>-matter. The threshold energy for the MoS2 material has been found and experimentally verified in the microscope. At energies higher than the energy threshold we show surface and edge defects produced by the <span class="hlt">electron</span> beam irradiation. Quantitative analysis at atomic level in the images obtained at 80 kV has been performed using the experimental images and via STEM simulations using SICSTEM software to determine the exact number of MoS2 layers. PMID:24929924</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhPl...23b3511K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhPl...23b3511K"><span id="translatedtitle">Characterization of <span class="hlt">electron</span> kinetics regime with <span class="hlt">electron</span> energy probability functions in inductively coupled hydrogen <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, June Young; Cho, Won-Hwi; Dang, Jeong-Jeung; Chung, Kyoung-Jae; Hwang, Y. S.</p> <p>2016-02-01</p> <p><span class="hlt">Electron</span> kinetics regime is characterized with the evolution of <span class="hlt">electron</span> energy probability functions (EEPFs) in inductively coupled hydrogen <span class="hlt">plasmas</span>. Measurements on EEPFs are carried out with a radio-frequency-compensated single Langmuir probe at the center of a planar-type hydrogen <span class="hlt">plasma</span> driven by 13.56 MHz wave frequency. Measured EEPFs deviate considerably from the Maxwellian distribution only at relatively high pressures (15-40 mTorr), and the effective <span class="hlt">electron</span> temperature steeply decreases as the gas pressure increases. Such evolution of the EEPF shapes with pressures is discussed in the consideration of the <span class="hlt">electron</span> energy relaxation length and various characteristic frequencies. It is found that the EEPFs show locally depleted <span class="hlt">electron</span> energy distribution where the <span class="hlt">electron</span>-molecule vibrational collision frequency exceeds the <span class="hlt">electron-electron</span> collision frequency at the local kinetics regime, while the measured EEPF is not dependent on the vibrational collision frequency at the non-local kinetics regime. Variation of the EEPF shape with distance from the heating region at the local kinetics regime is also well explained in the context of the energy relaxation length and <span class="hlt">electron</span>-molecule collision frequencies. This study indicates that the control of <span class="hlt">electron</span> energy distribution should be carried out in the consideration of <span class="hlt">electron</span> kinetic regime depending on the energy relaxation length for various hydrogen <span class="hlt">plasma</span> sources.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22127014','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22127014"><span id="translatedtitle">CURRENT <span class="hlt">SHEET</span> REGULATION OF SOLAR NEAR-RELATIVISTIC <span class="hlt">ELECTRON</span> INJECTION HISTORIES</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Agueda, N.; Sanahuja, B.; Vainio, R.; Dalla, S.; Lario, D.</p> <p>2013-03-10</p> <p>We present a sample of three large near-relativistic (>50 keV) <span class="hlt">electron</span> events observed in 2001 by both the ACE and the Ulysses spacecraft, when Ulysses was at high-northern latitudes (>60 Degree-Sign ) and close to 2 AU. Despite the large latitudinal distance between the two spacecraft, <span class="hlt">electrons</span> injected near the Sun reached both heliospheric locations. All three events were associated with large solar flares, strong decametric type II radio bursts and accompanied by wide (>212 Degree-Sign ) and fast (>1400 km s{sup -1}) coronal mass ejections (CMEs). We use advanced interplanetary transport simulations and make use of the directional intensities observed in situ by the spacecraft to infer the <span class="hlt">electron</span> injection profile close to the Sun and the interplanetary transport conditions at both low and high latitudes. For the three selected events, we find similar interplanetary transport conditions at different heliolatitudes for a given event, with values of the mean free path ranging from 0.04 AU to 0.27 AU. We find differences in the injection profiles inferred for each spacecraft. We investigate the role that sector boundaries of the heliospheric current <span class="hlt">sheet</span> (HCS) have on determining the characteristics of the <span class="hlt">electron</span> injection profiles. Extended injection profiles, associated with coronal shocks, are found if the magnetic footpoints of the spacecraft lay in the same magnetic sector as the associated flare, while intermittent sparse injection episodes appear when the spacecraft footpoints are in the opposite sector or a wrap in the HCS bounded the CME structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19870010644','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19870010644"><span id="translatedtitle"><span class="hlt">Plasma</span> heating, <span class="hlt">plasma</span> flow and wave production around an <span class="hlt">electron</span> beam injected into the ionosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Winckler, J. R.; Erickson, K. N.</p> <p>1986-01-01</p> <p>A brief historical summary of the Minnesota ECHO series and other relevant <span class="hlt">electron</span> beam experiments is given. The primary purpose of the ECHO experiments is the use of conjugate echoes as probes of the magnetosphere, but beam-<span class="hlt">plasma</span> and wave studies were also made. The measurement of quasi-dc electric fields and ion streaming during the ECHO 6 experiment has given a pattern for the <span class="hlt">plasma</span> flow in the hot <span class="hlt">plasma</span> region extending to 60m radius about the ECHO 6 <span class="hlt">electron</span> beam. The sheath and potential well caused by ion orbits is discussed with the aid of a model which fits the observations. ELF wave production in the <span class="hlt">plasma</span> sheath around the beam is briefly discussed. The new ECHO 7 mission to be launched from the Poker Flat range in November 1987 is described.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4557361','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4557361"><span id="translatedtitle">The solvation of <span class="hlt">electrons</span> by an atmospheric-pressure <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rumbach, Paul; Bartels, David M.; Sankaran, R. Mohan; Go, David B.</p> <p>2015-01-01</p> <p>Solvated <span class="hlt">electrons</span> are typically generated by radiolysis or photoionization of solutes. While <span class="hlt">plasmas</span> containing free <span class="hlt">electrons</span> have been brought into contact with liquids in studies dating back centuries, there has been little evidence that <span class="hlt">electrons</span> are solvated by this approach. Here we report direct measurements of solvated <span class="hlt">electrons</span> generated by an atmospheric-pressure <span class="hlt">plasma</span> in contact with the surface of an aqueous solution. The <span class="hlt">electrons</span> are measured by their optical absorbance using a total internal reflection geometry. The measured absorption spectrum is unexpectedly blue shifted, which is potentially due to the intense electric field in the interfacial Debye layer. We estimate an average penetration depth of 2.51.0?nm, indicating that the <span class="hlt">electrons</span> fully solvate before reacting through second-order recombination. Reactions with various <span class="hlt">electron</span> scavengers including H+, NO2?, NO3? and H2O2 show that the kinetics are similar, but not identical, to those for solvated <span class="hlt">electrons</span> formed in bulk water by radiolysis. PMID:26088017</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26088017','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26088017"><span id="translatedtitle">The solvation of <span class="hlt">electrons</span> by an atmospheric-pressure <span class="hlt">plasma</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rumbach, Paul; Bartels, David M; Sankaran, R Mohan; Go, David B</p> <p>2015-01-01</p> <p>Solvated <span class="hlt">electrons</span> are typically generated by radiolysis or photoionization of solutes. While <span class="hlt">plasmas</span> containing free <span class="hlt">electrons</span> have been brought into contact with liquids in studies dating back centuries, there has been little evidence that <span class="hlt">electrons</span> are solvated by this approach. Here we report direct measurements of solvated <span class="hlt">electrons</span> generated by an atmospheric-pressure <span class="hlt">plasma</span> in contact with the surface of an aqueous solution. The <span class="hlt">electrons</span> are measured by their optical absorbance using a total internal reflection geometry. The measured absorption spectrum is unexpectedly blue shifted, which is potentially due to the intense electric field in the interfacial Debye layer. We estimate an average penetration depth of 2.5 1.0 nm, indicating that the <span class="hlt">electrons</span> fully solvate before reacting through second-order recombination. Reactions with various <span class="hlt">electron</span> scavengers including H(+), NO2(-), NO3(-) and H2O2 show that the kinetics are similar, but not identical, to those for solvated <span class="hlt">electrons</span> formed in bulk water by radiolysis. PMID:26088017</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950047162&hterms=magnetic+anisotropy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dmagnetic%2Banisotropy','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950047162&hterms=magnetic+anisotropy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dmagnetic%2Banisotropy"><span id="translatedtitle">A study of weak anisotropy in <span class="hlt">electron</span> pressure in the tail current <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lee, D.-Y.; Voigt, G.-H.</p> <p>1995-01-01</p> <p>We adopt a magnetotail model with stretched field lines where ion motions are generally nonadiabatic and where it is assumed that the pressure anisotropy resides only in the <span class="hlt">electron</span> pressure tensor. We show that the magnetic field lines with p(perpendicular) greater than p(parallel) are less stretched than the corresponding field lines in the isotropic model. For p(parallel) greater than p(perpendicular), the magnetic field lines become more and more stretched as the anisotropy approaches the marginal firehose limit, p(parallel) = p(perpendicular) + B(exp 2)/mu(sub 0). We also show that the tail current density is highly enhanced at the firehose limit, a situation that might be subject to a microscopic instability. However, we emphasize that the enhancement in the current density is notable only near the center of the tail current <span class="hlt">sheet</span> (z = 0). Thus it remains unclear whether any microscopic instability can significantly alter the global magnetic field configuration of the tail. By comparing the radius of the field-line curvature at z = 0 with the particle's gyroradius, we suspect that even the conventional adiabatic description of <span class="hlt">electrons</span> may become questionable very close to the marginal firehose limit.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhRvB..88w5425H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhRvB..88w5425H"><span id="translatedtitle"><span class="hlt">Electronic</span> properties of mixed-phase graphene/h-BN <span class="hlt">sheets</span> using real-space pseudopotentials</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huang, ZhaoHui; Crespi, Vincent H.; Chelikowsky, James R.</p> <p>2013-12-01</p> <p>A major challenge for applications of graphene is the creation of a tunable <span class="hlt">electronic</span> band gap. Hexagonal boron nitride has a lattice very similar to that of graphene and a much larger band gap, but B-N and C do not alloy: B-C-N materials tend to phase separate into h-BN and C domains. Quantum confinement within the finite-sized C domains of a mixed B-C-N system can create a band gap, albeit within an inhomogeneous system. Here we investigate the properties of hybrid h-BN/C <span class="hlt">sheets</span> with real-space pseudopotential density functional theory. We find that the <span class="hlt">electronic</span> properties are determined not just by geometrical confinement, but also by the bonding character at the h-BN/C interface. B-C terminated carbon regions tend to have larger gaps than N-C terminated regions, suggesting that boron-carbon bonds are more stable. We examine two series of symmetric structures that represent different kinds of confinement: a graphene dot within a h-BN background and a h-BN antidot within a graphene background. The gaps in both cases vary inversely with the size of the graphenic region, as expected, and can be fit by simple empirical expressions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850029363&hterms=technologie&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dtechnologie','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850029363&hterms=technologie&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dtechnologie"><span id="translatedtitle">Simultaneous observation of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> in the near earth and distant magnetotail - ISEE-1 and ISEE-3</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Scholer, M.; Hovestadt, D.; Klecker, B.; Baumjohann, W.; Gloeckler, G.; Ipavich, F. M.; Baker, D. N.; Zwickl, R. D.; Tsurutani, B. T.</p> <p>1984-01-01</p> <p>Particle data have been acquired by the 1981-025 and 1982-019 spacecraft at geosynchronous orbit, as well as ISEE-1 in the near earth geomagnetic tail, and ISEE-3 in the distant geomagnetic tail. These observations are supplemented by ground-based magnetograms from near local midnight stations. Attention is given to a substorm recovery phase, and to observations of ion beams at the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary in the near earth and distant tail, respectively, which are found to flow in opposite directions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSH13E..04G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSH13E..04G"><span id="translatedtitle"><span class="hlt">Electron</span> <span class="hlt">Plasma</span> Oscillations and Related Effects Observed By Voyager 1 in the Interstellar <span class="hlt">Plasma</span> during 2014</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gurnett, D. A.; Kurth, W. S.; Stone, E. C.; Cummings, A. C.; Krimigis, S. M.; Decker, R. B.; Ness, N. F.; Burlaga, L. F.</p> <p>2014-12-01</p> <p>It is now well known that the Voyager 1 spacecraft crossed the heliopause into interstellar space in late August 2012. A key observation supporting this conclusion was the detection of <span class="hlt">electron</span> <span class="hlt">plasma</span> oscillations in October-November 2012, and again in April-May 2013. These observations showed the local <span class="hlt">electron</span> density was consistent with the expected density of the local interstellar <span class="hlt">plasma</span>. Such <span class="hlt">plasma</span> oscillations are believed to be excited by <span class="hlt">electron</span> beams originating from shocks associated with global merged interaction regions (GMIRs) propagating outward from the Sun. Now, another series of <span class="hlt">plasma</span> oscillation events has been observed starting in early February 2014, and continuing to the present time (late July 2014). These events show a clear association with changes in the cosmic ray intensities and anisotropies that are suggestive of a solar disturbance propagating outward through the interstellar <span class="hlt">plasma</span>. The interpolated radial density profile inferred from these and the previous <span class="hlt">plasma</span> oscillations shows that after crossing the heliopause the <span class="hlt">electron</span> density increased rapidly from 0.055 cm-3 in late October 2012, at 122 AU, to a broad maximum of about 0.090 to 0.095 cm-3 in July-August 2013, at about 125 AU, followed by a slow decrease to about 0.085 cm-3 in the most recent data, at 128 AU. This density profile is consistent with a large-scale compression (i.e., pileup) of the interstellar <span class="hlt">plasma</span> near the nose of the heliosphere, together with a smaller scale <span class="hlt">plasma</span> depletion layer immediately adjacent to the heliopause, as suggested by Fuselier and Cairns [2013].</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <center> <div class="footer-extlink text-muted"><small>Some links on this page may take you to non-federal websites. 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