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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. Strong electron heating in the near-Earth plasma sheet.

    NASA Astrophysics Data System (ADS)

    Grigorenko, Elena; Zelenyi, Lev; Kronberg, Elena; Daly, Patrick

    2016-07-01

    Strong perturbations of the Plasma Sheet (PS) magnetic field in the course of magnetic dipolarization are often followed by the generation of magnetic turbulence and plasma heating. Various plasma instabilities and waves can be excited during these processes, which may affect ion and electron velocity distributions in a different way. We have analyzed 70 crossings of the central PS by Cluster spacecraft (s/c) at -19 < X < -8 Re in 2001-2005. We have found that in 32 intervals the ratio of Tion/Tele dropped in the central PS down to <3.0, which denotes significant electron heating. The detailed analysis of these crossings showed that in majority of these events strong magnetic dipolarizations and magnetic turbulence were observed. In the present study we discuss possible mechanisms of such strong electron heating.

  3. 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></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMSM44A..08G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMSM44A..08G"><span id="translatedtitle">Transport of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> <span class="hlt">electrons</span> to the geostationary distances</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ganushkina, N. Y.; Amariutei, O. A.; Shprits, Y.; Liemohn, M. W.</p> <p>2012-12-01</p> <p>The transport and acceleration of low energy <span class="hlt">electrons</span> (10-250 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 November 6-7, 1997 and June 12-14, 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 model was compared to the observed <span class="hlt">electron</span> fluxes in four energy ranges measured onboard the LANL spacecraft by the SOPA instrument. It was found that the large-scale convection in combination with substorm-associated impulsive fields are 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, comparison between the modeled <span class="hlt">electron</span> fluxes and observed ones showed two orders of difference most likely due to inaccuracy of <span class="hlt">electron</span> boundary conditions and omission of the important loss processes due to wave-particle interactions. This did not allow us to accuractly reproduce the dynamics of 150-225 keV <span class="hlt">electron</span> fluxes. The choice of the large-scale convection electric field model used in simulations did not significantly 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 Boyle et al. [1997] models at the 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 three 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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25638082','PUBMED'); return false;" href="https://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="https://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.</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.osti.gov/scitech/biblio/22518992','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22518992"><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://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chasapis, A.; Retinò, A.; Sahraoui, F.; Canu, P.; Vaivads, A.; Khotyaintsev, Yu. V.; Sundkvist, D.; Greco, A.; Sorriso-Valvo, L.</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://ntrs.nasa.gov/search.jsp?R=19940033533&hterms=electrostatic+waves&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Delectrostatic%2Bwaves','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19940033533&hterms=electrostatic+waves&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Delectrostatic%2Bwaves"><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://ntrs.nasa.gov/search.jsp?R=19910050774&hterms=electrostatic+waves&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Delectrostatic%2Bwaves','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910050774&hterms=electrostatic+waves&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Delectrostatic%2Bwaves"><span id="translatedtitle">Simultaneous excitation of broadband electrostatic noise and <span class="hlt">electron</span> cyclotron waves 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>Berchem, Jean P.; Schriver, David; Ashour-Abdalla, Maha</p> <p>1991-01-01</p> <p><span class="hlt">Electron</span> cyclotron harmonics and broadband electrostatic noise (BEN) are often observed in the earth's outer <span class="hlt">plasma</span> <span class="hlt">sheet</span>. While it is well known that ion beams in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer can generate BEN, new two-dimensional electrostatic simulations show that field-aligned ion beams with a small perpendicular ring distribution can drive not only BEN, but also <span class="hlt">electron</span> cyclotron harmonic (ECH) waves simultaneously. Simulation results are presented here using detailed diagnostics of wave properties, including dispersion relations of all wave modes.</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://adsabs.harvard.edu/abs/2013JGRA..118.6042W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JGRA..118.6042W"><span id="translatedtitle">Sources of <span class="hlt">electron</span> pitch angle anisotropy in the magnetotail <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>Walsh, Andrew P.; Fazakerley, A. N.; Forsyth, C.; Owen, C. J.; Taylor, M. G. G. T.; Rae, I. J.</p> <p>2013-10-01</p> <p>We survey the properties of <span class="hlt">electron</span> pitch angle distributions in the magnetotail <span class="hlt">plasma</span> <span class="hlt">sheet</span> at a distance between 15 and 19 RE from the Earth, using data from the <span class="hlt">Plasma</span> <span class="hlt">Electron</span> and Current Experiment (PEACE) instrument. We limit our survey to those pitch angle distributions measured when the interplanetary magnetic field (IMF) had been steadily northward or steadily southward for the previous 3 h. We find that, at sub-keV energies, the <span class="hlt">plasma</span> <span class="hlt">sheet</span> <span class="hlt">electron</span> pitch angle distribution has an anisotropy such that there is a higher differential energy flux of <span class="hlt">electrons</span> in the (anti-) field-aligned directions. Fitting the measured pitch angle distributions with both a single and two component kappa distribution reveals that this anisotropy is the result of the presence of a second, cold, component of <span class="hlt">electrons</span> that is observed more often than not, and occurs during both the northward and southward IMF intervals. We present evidence that suggests the cold <span class="hlt">electron</span> component has an ionospheric, rather than magnetosheath, source and is linked to the large-scale field-aligned current systems that couple the magnetosphere and ionosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMSM11A1568S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMSM11A1568S"><span id="translatedtitle"><span class="hlt">Plasma</span> <span class="hlt">Sheet</span> Energy Distributions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sotirelis, T.; Lee, A. R.; Newell, P. T.</p> <p>2009-12-01</p> <p>Energy spectra of <span class="hlt">electrons</span> and ions, as observed by DMSP, are fit to various distributions. The goal is to characterize the inner edge of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, so the focus is on large scale <span class="hlt">plasma</span> <span class="hlt">sheet</span> properties. Lower energy <span class="hlt">electron</span> populations are ignored as they appear to be small-scale transients. Maxwellian, kappa and power-law distributed spectra are considered. Non-thermal ion distributions appear with greater frequency than anticipated. In order to be thermally distributed the differential energy flux must rise with a slope of ~2 toward a peak, after which the flux should fall sharply. The figure shows an apparently non-thermal ion distribution, together with a Maxwellian fit. The results from fits for one full year are presented.</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://adsabs.harvard.edu/abs/2015AGUFMSM14A..04K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM14A..04K"><span id="translatedtitle">The Major Pathways of the <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> <span class="hlt">Electrons</span> Precipitated in the Regions of Diffuse Aurora</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Khazanov, G. V.</p> <p>2015-12-01</p> <p>The precipitation of high-energy magnetospheric <span class="hlt">electrons</span> (E ~ 600eV - 10 KeV) in the diffuse aurora contributes significant energy flux into the Earth's ionosphere. It has been found (Khazanov et al. [2014, 2015]) that in order to fully understand the formation of this flux at the upper ionospheric boundary, ~ 700 - 800 km, it is important to consider the coupled ionosphere-magnetosphere system. In the diffuse aurora, precipitating <span class="hlt">electrons</span> initially injected from the <span class="hlt">plasma</span> <span class="hlt">sheet</span> via wave-particle interaction processes degrade in the atmosphere toward lower energies and produce secondary <span class="hlt">electrons</span> via impact ionization of the neutral atmosphere. These initially precipitating <span class="hlt">electrons</span> of magnetospheric origin can be additionally reflected back into the magnetosphere by the two magnetically conjugated atmospheres, leading to a series of multiple reflections that can greatly influence the initially precipitating flux at the upper ionospheric boundary (700-800 km) and the resultant population of secondary <span class="hlt">electrons</span> and <span class="hlt">electrons</span> cascading toward lower energies. In this talk we present the solution of the Boltzman-Landau kinetic equation that uniformly describes the entire <span class="hlt">electron</span> distribution function in the diffuse aurora, including the affiliated production of secondary <span class="hlt">electrons</span> (E < 600eV) and their energy interplay in the magnetosphere and two conjugated ionospheres. This solution takes into account, for the first time, formation <span class="hlt">electron</span> distribution function in the region of diffuse aurora starting with the primary injection of <span class="hlt">plasma</span> <span class="hlt">sheet</span> <span class="hlt">electrons</span> via both <span class="hlt">electron</span> cyclotron harmonic waves and whistler mode chorus waves to the loss cone, and their follow up multiple atmospheric reflections in the two magnetically conjugated ionospheres. It is demonstrated that magnetosphere-ionosphere coupling is the key element in the formation of <span class="hlt">electron</span> distribution function in the region of diffuse aurora.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM14B..05W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM14B..05W"><span id="translatedtitle">Sources of <span class="hlt">Electron</span> Pitch Angle Anisotropy in the Magnetotail <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>Walsh, A. P.; Fazakerley, A. N.; Forsyth, C.; Owen, C. J.; Taylor, M. G.; Rae, J.</p> <p>2013-12-01</p> <p>We survey the properties of <span class="hlt">electron</span> pitch angle distributions in the magnetotail <span class="hlt">plasma</span> <span class="hlt">sheet</span> at a distance between 15 and 19 RE from the Earth, using data from the Cluster PEACE instrument. We limit our survey to those pitch angle distributions measured when the IMF had been steadily northward or steadily southward for the previous three hours. We find that, at sub- keV energies the <span class="hlt">plasma</span> <span class="hlt">sheet</span> <span class="hlt">electron</span> pitch angle distribution has an anisotropy such that there is a higher differential energy flux of <span class="hlt">electrons</span> in the (anti- ) field-aligned directions. Fitting the measured pitch angle distributions with both a single and two component kappa distribution reveals that this anisotropy is the result of the presence of a second, cold, component of <span class="hlt">electrons</span> that is observed more often than not, and occurs during both the northward and southward IMF intervals. We present evidence that suggests the cold <span class="hlt">electron</span> component has an ionospheric, rather than magnetosheath, source and is linked to the large scale field aligned current systems that couple the magnetosphere and ionosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1610718G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1610718G"><span id="translatedtitle">Transport and acceleration of <span class="hlt">plasma</span> <span class="hlt">sheet</span> <span class="hlt">electrons</span> to geostationary orbit (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ganushkina, Natalia</p> <p>2014-05-01</p> <p>Transport and acceleration of the <span class="hlt">electrons</span> with energies less than 200 keV from the <span class="hlt">plasma</span> <span class="hlt">sheet</span> to geostationary orbit were investigated. These <span class="hlt">electron</span> fluxes constitute the seed population for the high energy MeV particles in the radiation belts and are responsible for hazardous phenomena such as surface charging. We modeled several quiet and storm events, when the presence of isolated substorms was seen in the AE index. We used the Inner Magnetosphere Particle Transport and Acceleration Model (IMPTAM) with the boundary at 10 Re with Tsyganenko and Mukai moment values for the <span class="hlt">electrons</span> in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. The output of the IMPTAM modeling was compared to the observed <span class="hlt">electron</span> fluxes in ten energy ranges (from 5 to 50 keV) measured onboard the AMC 12 geostationary spacecraft by the CEASE II ESA instrument and to LANL data from MPA and SOPA instruments. The behavior of the fluxes depends on the <span class="hlt">electron</span> energy. IMPTAM model, driven by the observed parameters such as IMF By and Bz, solar wind velocity, number density and dynamic pressure and the Dst index, was not able to reproduce the observed peaks in the <span class="hlt">electron</span> fluxes when no significant variations are present in those parameters. The variations of the observed fluxes during this non-storm period are due to substorm activity. We introduced the substorm-associated electromagnetic fields by launching several electromagnetic pulses at the substorm onsets during the modeled period. The substorm-associated increases in the observed fluxes can be captured by IMPTAM when substorm-associated electromagnetic fields are taken into account. Modifications of the pulse model used here are needed, especially related to the pulse front velocity and arrival time.</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> </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://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/1989JGR....9411791K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1989JGR....9411791K"><span id="translatedtitle">On Jovian <span class="hlt">plasma</span> <span class="hlt">sheet</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>Khurana, Krishan K.; Kivelson, Margaret G.</p> <p>1989-09-01</p> <p>Several models of Jovian <span class="hlt">plasma</span> <span class="hlt">sheet</span> structure are studied, focusing on the ways in which they organize aspects of the observed Voyager 2 magnetic field characteristics as a function of radial distance from Jupiter. A technique which locates the interfaces between the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and the lobes from magnetic data is presented. This boundary location is used to test models of the magnetotail. Improved variations of the hinged-magnetodisk and the magnetic anomaly models are given in which the parameters are optimized by using structural information from observed magnetic equator and <span class="hlt">plasma-sheet</span>-lobe boundary crossings.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..121.4331T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..121.4331T"><span id="translatedtitle"><span class="hlt">Electron</span> acceleration associated with the magnetic flux pileup regions in the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span>: A multicase study</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.; Zhou, M.; Yao, Z. H.; Shi, F.</p> <p>2016-05-01</p> <p>Using the Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations, we study <span class="hlt">electron</span> acceleration (<30 keV) in the magnetic flux pileup regions (FPRs) in the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> (X ~ -10 RE). We present three cases of FRPs associated with dipolarization fronts and substorm dipolarization. Based on the characteristics of the magnetic field, we defined the magnetic field enhancement region (MFER) as the magnetic field with significant ramp that is usually observed near the dipolarization front boundary layer. On the other side, the increased magnetic field without a significant ramp is the rest of a FPR. Our results show that betatron acceleration dominates for 10-30 keV <span class="hlt">electrons</span> inside the MFER, whereas Fermi acceleration dominates for 10-30 keV <span class="hlt">electrons</span> inside the rest of the FPR. Betatron acceleration is caused by the enhancement of the local magnetic field, whereas Fermi acceleration is related to the shrinking length of magnetic field line. These accelerated <span class="hlt">electrons</span> inside the FPRs in the near-Earth tail play a potentially important role in the evolution of the Earth's <span class="hlt">electron</span> radiation belt and substorms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoRL..43.6044G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoRL..43.6044G"><span id="translatedtitle">Electric fields associated with small-scale magnetic holes in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>: Evidence for <span class="hlt">electron</span> currents</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goodrich, Katherine A.; Ergun, Robert E.; Stawarz, Julia E.</p> <p>2016-06-01</p> <p>We report observations of magnetic holes (MHs) in the near-Earth (8 RE to 12 RE) <span class="hlt">plasma</span> <span class="hlt">sheet</span> that have physical sizes perpendicular to the magnetic field (B) on the order of the ion Larmor radius (ρi) and, more importantly, have current layers less than ρi in thickness. Small-scale MHs can have >90% depletion in |B| and are commonly associated with the braking of bursty bulk flow events. The generation of MHs is often attributed to magnetohydrodynamic (MHD) instabilities, which requires a size greater than ρi; the depletion in |B| is from an ion current consistent with a pressure gradient. Electric field (E) observations indicate a negative potential inside of small-scale MHs that creates an outward E at the boundary, which drives an E × B <span class="hlt">electron</span> current in a thin layer. These observations indicate that a Hall <span class="hlt">electron</span> current is primarily responsible for the depletion of |B| in small-scale magnetic holes, rather than the ion pressure gradient.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JGRA..116.6215J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JGRA..116.6215J"><span id="translatedtitle">A statistical study of the inner edge of the <span class="hlt">electron</span> <span class="hlt">plasma</span> <span class="hlt">sheet</span> and the net convection potential as a function of geomagnetic activity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jiang, F.; Kivelson, M. G.; Walker, R. J.; Khurana, K. K.; Angelopoulos, V.; Hsu, T.</p> <p>2011-06-01</p> <p>A widely accepted explanation of the location of the inner edge of the <span class="hlt">electron</span> <span class="hlt">plasma</span> <span class="hlt">sheet</span> and its dependence on <span class="hlt">electron</span> energy is based on drift motions of individual particles. The boundary is identified as the separatrix between drift trajectories linking the tail to the dayside magnetopause (open paths) and trajectories closed around the Earth. A statistical study of the inner edge of the <span class="hlt">electron</span> <span class="hlt">plasma</span> <span class="hlt">sheet</span> using THEMIS Electrostatic Analyzer <span class="hlt">plasma</span> data from November 2007 to April 2009 enabled us to examine this model. Using a dipole magnetic field and a Volland-Stern electric field with shielding, we find that a steady state drift boundary model represents the average location of the <span class="hlt">electron</span> <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary and reflects its variation with the solar wind electric field in the local time region between 21:00 and 06:00, except at high activity levels. However, the model does not reproduce the observed energy dispersion of the boundaries. We have also used the location of the inner edge of the <span class="hlt">electron</span> <span class="hlt">plasma</span> <span class="hlt">sheet</span> to parameterize the potential drop of the tail convection electric field as a function of solar wind electric field (Esw) and geomagnetic activity. The range of Esw examined is small because the data were acquired near solar minimum. For the range of values tested (meaningful statistics only for Esw < 2 mV/m), reasonably good agreement is found between the potential drop of the tail convection electric field inferred from the location of the inner edge and the polar cap potential drop calculated from the model of Boyle et al. (1997).</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/2010AGUFMSM41C1880J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMSM41C1880J"><span id="translatedtitle">Magnetospheric convection strength inferred from inner edge of the <span class="hlt">electron</span> <span class="hlt">plasma</span> <span class="hlt">sheet</span> and its relation to the polar cap potential drop</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jiang, F.; Kivelson, M. G.; Walker, R. J.; Khurana, K. K.; Angelopoulos, V.</p> <p>2010-12-01</p> <p>The sharp inner edge of the nightside <span class="hlt">electron</span> <span class="hlt">plasma</span> <span class="hlt">sheet</span> observed by the THEMIS spacecraft is shown to provide a measure of the effective convection strength that transports <span class="hlt">plasma</span> <span class="hlt">sheet</span> <span class="hlt">plasma</span> into the inner magnetosphere. The effective convection strength is characterized by the difference of potential between the magnetopause terminators at dawn and at dusk. We have surveyed inner boundary crossings of the <span class="hlt">electron</span> <span class="hlt">plasma</span> <span class="hlt">sheet</span> measured by three THEMIS probes on orbits from Nov. 2007 to Apr. 2009. The values of the convection electric potential are inferred from the locations of the inner edge for different energy channels using a steady-state drift boundary model with a dipole magnetic field and a Volland-Stern electric field. When plotted against the solar wind electric field ( ), the convection electric potential is found to have a quasi-linear relationship with the driving solar wind electric field for the range of values tested (meaningful statistics only for Esw < 1.5 mV/m). Reasonably good agreement is found between the convection electric potential and the polar-cap potential drop calculated from model of Boyle et al. [1997] when the degree of shielding in the Volland-Stern potential is selected as gamma=1.5.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014cosp...40E1811L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014cosp...40E1811L&link_type=ABSTRACT"><span id="translatedtitle">Rapid loss of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> energetic <span class="hlt">electrons</span> associated with the growth of whistler mode waves inside the 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>Li, L. Y.; Yu, J.; Cao, J. B.</p> <p></p> <p>During the interval 07:45:36- 07:54:24 UT on 24 August 2005, Cluster satellites (C1 and C3) observed an obvious loss of energetic <span class="hlt">electrons</span> (3.2- 95keV) associated with the growth of whistler mode waves inside some bursty bulk flows (BBFs) in the midtail <span class="hlt">plasma</span> <span class="hlt">sheet</span> (X _{GSM}= -17.25 R _{E}). However, the fluxes of the higher-energy <span class="hlt">electrons</span> (>128keV) and energetic ions (10- 160 keV) were relatively stable in the BBF-impacted regions. The energy-dependent <span class="hlt">electron</span> loss inside the BBFs is mainly due to the energy-selective pitch angle scatterings by whistler mode waves within the time scales from several seconds to several minutes, and the <span class="hlt">electron</span> scatterings in different pitch angle distributions are different in the wave growth regions. The <span class="hlt">plasma</span> <span class="hlt">sheet</span> energetic <span class="hlt">electrons</span> have mainly a quasi-perpendicular pitch angle distribution (30(°) <alpha<150(°) ) during the expansion-to-recovery development of a substorm (AE index decreases from 1677 nT to 1271 nT), and their loss can occur at almost all pitch angles in the wave growth regions inside the BBFs. Unlike the energetic <span class="hlt">electrons</span>, the low-energy <span class="hlt">electrons</span> (0.073- 2.1keV) have initially a field-aligned pitch angle distribution (0(°) <alpha<30(°) and 150(°) <alpha<180(°) ) in the absence of whistler mode waves, and their loss in field-aligned directions is accompanied by their increase in quasi-perpendicular directions in the wave growth regions, but the loss of the low-energy <span class="hlt">electrons</span> inside the BBFs is not obvious in the presence of their large background fluxes. These observations indicate that the resonant <span class="hlt">electrons</span> in an anisotropic pitch angle distribution mainly undergo the rapid pitch angle scattering loss during the wave-particle resonances.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5389125','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5389125"><span id="translatedtitle"><span class="hlt">Plasma</span> <span class="hlt">sheet</span> behavior during substorms</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hones, E.W. Jr.</p> <p>1983-01-01</p> <p>Auroral or magnetic substorms are periods of enhanced auroral and geomagnetic activity lasting one to a few hours that signify increased dissipation of energy from the magnetosphere to the earth. Data acquired during the past decade from satellites in the near-earth sector of the magnetotail have suggested that during a substorm part of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> is severed from earth by magnetic reconnection, forming a plasmoid, i.e., a body of <span class="hlt">plasma</span> and closed magnetic loops, that flows out of the tail into the solar wind, thus returning <span class="hlt">plasma</span> and energy that have earlier been accumulated from the solar wind. Very recently this picture has been dramatically confirmed by observations, with the ISEE 3 spacecraft in the magnetotail 220 R/sub E/ from earth, of plasmoids passing that location in clear delayed response to substorms. It now appears that plasmoid release is a fundamental process whereby the magnetosphere gives up excess stored energy and <span class="hlt">plasma</span>, much like comets are seen to do, and that the phenomena of the substorm seen at earth are a by-product of that fundamental process.</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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002PhDT........13F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002PhDT........13F"><span id="translatedtitle">Kinetic processes in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> observed during auroral activity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fillingim, Matthew Owen</p> <p></p> <p>In this dissertation we analyze <span class="hlt">plasma</span> <span class="hlt">sheet</span> magnetic field and <span class="hlt">plasma</span> data observed during varying levels of auroral activity from very small, isolated events known as pseudobreakups to large, global events known as substorms. The <span class="hlt">plasma</span> and magnetic field data are taken from instruments onboard the WIND spacecraft while it traverses the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span>. Simultaneous global auroral images from POLAR/UVI allow us to determine the auroral activity level. The goal of this dissertation is to provide the most complete set of <span class="hlt">plasma</span> <span class="hlt">sheet</span> observations during auroral activity currently available. The kinetic aspects of the <span class="hlt">plasma</span> dynamics which have largely been ingnored in other works are emphasized here. We have the capability to resolve changes in the three dimensional ion distribution functions with a time resolution comparable to or faster than the local ion gyroperiod. In addition, we consider the typically neglected <span class="hlt">electron</span> dynamics when relating <span class="hlt">plasma</span> <span class="hlt">sheet</span> processes to the aurora. We find that the <span class="hlt">plasma</span> <span class="hlt">sheet</span> signatures of both pseudobreakups and substorms appear very similar. During both types of events, increases in auroral precipitation into the ionosphere are associated with large amplitude, high frequency magnetic field fluctuations, large Earthward ion < v>, increases in the fluxes of high energy ions and <span class="hlt">electrons</span>, and hardening of the <span class="hlt">electron</span> spectrum. Both ion and <span class="hlt">electron</span> distributions appear to be composed of multiple components. Electromagnetic waves with power at frequencies up to and above the local proton gyrofrequency area also observed. Additionally, the ion distributions can change significantly in one gyroperiod. Together, these results imply that the microphysical processes occurring in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> during pseudobreakups and substorms are the same and that kinetic effects are important. Therefore, magnetohydrodynamics (MHD) cannot adequately describe the physics occurring during large ion < v> events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000APS..DPPMP1039S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000APS..DPPMP1039S&link_type=ABSTRACT"><span id="translatedtitle">Effect of <span class="hlt">Plasma</span> Irradiation on Formation of TiO2 Thin-Film in <span class="hlt">Electron</span> Cyclotron Resonance <span class="hlt">Sheet</span> <span class="hlt">Plasma</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>Sugihara, Shinji; Ishii, Shigeyuki; Honbo, Eiji; Kato, Yushi</p> <p>2000-10-01</p> <p>We have studied the effect of <span class="hlt">plasma</span> irradiation on formation of TiO2 thin-films. Substrates of deposition are irradiated by high-purity <span class="hlt">plasma</span> of the <span class="hlt">electron</span> cyclotron resonance (ECR) source. TiO2 thin-films are formed by reactive sputtering deposition. In the <span class="hlt">plasma</span> source, divergent magnetic fields are formed with external permanent magnets whose N poles face each other. Microwave of 2.45-GHz frequency is launched through a quartz window from a slot antenna in-between the magnets. The generated <span class="hlt">plasma</span> flows to side walls along the divergent magnetic fields. On one side a Ti target is placed and on the other a glass substrate is placed. The target form is a rectangle and the substrate is placed at a distance of 15 cm. A shutter is placed in front of the substrate to prevent <span class="hlt">plasma</span> flowing from the resonance zone. Argon and oxygen gases are used for reactive sputtering and the working pressure is about 0.01 - 0.1 Pa. The negative dc bias of 1000 V is applied to the target for sputtering. The generated films are of rutile with shutter opened and of anatase with shutter closed. We will try to clear whether the effect is due to annealing or others.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060009466&hterms=fgm&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dfgm','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060009466&hterms=fgm&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dfgm"><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://ntrs.nasa.gov/search.jsp?R=19850029387&hterms=terrestre&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dterrestre','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850029387&hterms=terrestre&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dterrestre"><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://www.osti.gov/scitech/servlets/purl/874183','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/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.; Scorey, Clive; Sikka, Vinod K.; Deevi, Seetharama C.; Fleischhauer, Grier; Lilly, Jr., A. Clifton; German, Randall M.</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/2015AGUFMSM22A..07L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM22A..07L"><span id="translatedtitle">Characteristics of DC electric fields in transient <span class="hlt">plasma</span> <span class="hlt">sheet</span> events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Laakso, H. E.; Escoubet, C. P.; Masson, A.</p> <p>2015-12-01</p> <p>We take an advantage of five different DC electric field measurements in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> available from the EFW double probe experiment, EDI <span class="hlt">electron</span> drift instrument, CODIF and HIA ion spectrometers, and PEACE <span class="hlt">electron</span> spectrometer on the four Cluster spacecraft. The calibrated observations of the three spectrometers are used to determine the proton and <span class="hlt">electron</span> velocity moments. The velocity moments can be used to estimate the proton and <span class="hlt">electron</span> drift velocity and furthermore the DC electric field, assuming that the <span class="hlt">electron</span> and proton velocity perpendicular to the magnetic field is dominated by the ExB drift motion. Naturally when ions and <span class="hlt">electrons</span> do not perform a proper drift motion, which can happen in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, the estimated DC electric field from ion and <span class="hlt">electron</span> motion is not correct. However, surprisingly often the DC electric fields estimated from <span class="hlt">electron</span> and ion motions are identical suggesting that this field is a real DC electric field around the measurement point. As the measurement techniques are so different, it is quite plausible that when two different measurements yield the same DC electric field, it is the correct field. All five measurements of the DC electric field are usually not simultaneously available, especially on Cluster 2 where CODIF and HIA are not operational, or on Cluster 4 where EDI is off. In this presentation we investigate DC electric field in various transient <span class="hlt">plasma</span> <span class="hlt">sheet</span> events such as dipolarization events and BBF's and how the five measurements agree or disagree. There are plenty of important issues that are considered, e.g., (1) what kind of DC electric fields exist in such events and what are their spatial scales, (2) do <span class="hlt">electrons</span> and ions perform ExB drift motions in these events, and (3) how well the instruments have been calibrated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22489978','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22489978"><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://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sharma, Suresh C.; Gupta, Neha</p> <p>2015-12-15</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</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://ntrs.nasa.gov/search.jsp?R=19780068427&hterms=dynamic+population&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Ddynamic%2Bpopulation','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19780068427&hterms=dynamic+population&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Ddynamic%2Bpopulation"><span id="translatedtitle">High beta <span class="hlt">plasma</span> in the dynamic Jovian 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>Walker, R. J.; Kivelson, M. G.; Schardt, A. W.</p> <p>1978-01-01</p> <p>The equatorial current <span class="hlt">sheet</span>, which Pioneer 10 repeatedly encountered on its outbound pass through the Jovian magnetosphere, frequently was associated with intense fluxes of energetic protons. Simultaneous observations of the changes in the energetic proton flux and in the magnetic-field magnitude demonstrate that the current <span class="hlt">sheet</span> is embedded in a high-beta <span class="hlt">plasma</span> in which high-energy (above 60 keV) ions frequently are the dominant constituents. Large differences in the <span class="hlt">plasma</span> temperature and the thickness of this <span class="hlt">plasma</span> <span class="hlt">sheet</span> between encounters only 10 hours apart indicate that the Jovian <span class="hlt">plasma</span> <span class="hlt">sheet</span> is very dynamic on a time scale of hours. Occasional observations of significant temporal variations in the magnetic field and particle populations during periods within the <span class="hlt">plasma</span> <span class="hlt">sheet</span> may represent in situ observations of Jovian magnetic disturbances. Comparison with previous observations suggests that low-energy (not more than 5 keV) <span class="hlt">plasma</span> contributes less than 3% to the current-<span class="hlt">sheet</span> energy density.</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://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('https://www.ncbi.nlm.nih.gov/pubmed/25526132','PUBMED'); return false;" href="https://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="https://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.</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="https://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://adsabs.harvard.edu/abs/2016JGRA..121.4452K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..121.4452K"><span id="translatedtitle">Slow electrostatic solitary waves in Earth's <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>Kakad, Amar; Kakad, Bharati; Anekallu, Chandrasekhar; Lakhina, Gurbax; Omura, Yoshiharu; Fazakerley, Andrew</p> <p>2016-05-01</p> <p>We modeled Cluster spacecraft observations of slow electrostatic solitary waves (SESWs) in the Earth's northern <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer (PSBL) region on the basis of nonlinear fluid theory and fluid simulation. Various <span class="hlt">plasma</span> parameters observed by the Cluster satellite at the time of the SESWs were examined to investigate the generation process of the SESWs. The nonlinear fluid model shows the coexistence of slow and fast ion acoustic waves and the presence of <span class="hlt">electron</span> acoustic waves in the PSBL region. The fluid simulations, performed to examine the evolution of these waves in the PSBL region, showed the presence of an extra mode along with the waves supported by the nonlinear fluid theory. This extra mode is identified as the Buneman mode, which is generated by relative drifts of ions and <span class="hlt">electrons</span>. A detailed investigation of the characteristics of the SESWs reveals that the SESWs are slow ion acoustic solitary waves.</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="https://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://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://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1990JGR....9514987H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1990JGR....9514987H&link_type=ABSTRACT"><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://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hammond, C. Max; Walker, Raymond J.; Kivelson, Margaret G.</p> <p>1990-09-01</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://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://adsabs.harvard.edu/abs/2016ApJ...827L..28H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...827L..28H"><span id="translatedtitle">The Dynamical 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 G.</p> <p>2016-08-01</p> <p>Turbulence profoundly affects particle transport and <span class="hlt">plasma</span> heating in many astrophysical <span class="hlt">plasma</span> environments, from galaxy clusters to the solar corona and solar wind to Earth's magnetosphere. Both fluid and kinetic simulations of <span class="hlt">plasma</span> turbulence ubiquitously generate coherent structures, in the form of current <span class="hlt">sheets</span>, at small scales, and the locations of these current <span class="hlt">sheets</span> appear to be associated with enhanced rates of dissipation of the turbulent energy. Therefore, illuminating the origin and nature of these current <span class="hlt">sheets</span> is critical to identifying the dominant physical mechanisms of dissipation, a primary aim at the forefront of <span class="hlt">plasma</span> turbulence research. Here, we present evidence from nonlinear gyrokinetic simulations that strong nonlinear interactions between counterpropagating Alfvén waves, or strong Alfvén wave collisions, are a natural mechanism for the generation of current <span class="hlt">sheets</span> in <span class="hlt">plasma</span> turbulence. Furthermore, we conceptually explain this current <span class="hlt">sheet</span> development in terms of the nonlinear dynamics of Alfvén wave collisions, showing that these current <span class="hlt">sheets</span> arise through constructive interference among the initial Alfvén waves and nonlinearly generated modes. The properties of current <span class="hlt">sheets</span> generated by strong Alfvén wave collisions are compared to published observations of current <span class="hlt">sheets</span> in the Earth's magnetosheath and the solar wind, and the nature of these current <span class="hlt">sheets</span> leads to the expectation that Landau damping of the constituent Alfvén waves plays a dominant role in the damping of turbulently generated current <span class="hlt">sheets</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008APS..DPPTI1004K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008APS..DPPTI1004K"><span id="translatedtitle">Pulsed <span class="hlt">Plasma</span> <span class="hlt">Electron</span> Sources</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Krasik, Yakov</p> <p>2008-11-01</p> <p>Pulsed (˜10-7 s) <span class="hlt">electron</span> beams with high current density (>10^2 A/cm^2) are generated in diodes with electric field of E > 10^6 V/cm. The source of <span class="hlt">electrons</span> in these diodes is explosive emission <span class="hlt">plasma</span>, which limits pulse duration; in the case E < 10^5 V/cm this <span class="hlt">plasma</span> is not uniform and there is a time delay in its formation. Thus, there is a continuous interest in research of <span class="hlt">electron</span> sources which can be used for generation of uniform <span class="hlt">electron</span> beams produced at E <= 10^5 V/cm. In the present report, several types of <span class="hlt">plasma</span> <span class="hlt">electron</span> source (PES) will be considered. The first type of PES is fiber-based cathodes, with and without CsI coating. The operation of these cathodes is governed by the formation of the flashover <span class="hlt">plasma</span> which serves as a source of <span class="hlt">electrons</span>. The second type of PES is the ferroelectric <span class="hlt">plasma</span> source (FPS). The operation of FPS, characterized by the formation of dense surface flashover <span class="hlt">plasma</span> is accompanied also by the generation of fast microparticles and energetic neutrals. The latter was explained by Coulomb micro-explosions of the ferroelectric surface due to an large time-varying electric field at the front of the expanding <span class="hlt">plasma</span>. A short review of recent achievements in the operation of a multi-FPS-assisted hollow anode to generate a large area <span class="hlt">electron</span> beam will be presented as well. Finally, parameters of the <span class="hlt">plasma</span> produced by a multi-capillary cathode with FPS and velvet igniters will be discussed. Ya. E. Krasik, J. Z. Gleizer, D. Yarmolich, A. Krokhmal, V. Ts. Gurovich, S.Efimov, J. Felsteiner V. Bernshtam, and Yu. M. Saveliev, J. Appl. Phys. 98, 093308 (2005). Ya. E. Krasik, A. Dunaevsky, and J. Felsteiner, Phys. <span class="hlt">Plasmas</span> 8, 2466 (2001). D. Yarmolich, V. Vekselman, V. Tz. Gurovich, and Ya. E. Krasik, Phys. Rev. Lett. 100, 075004 (2008). J. Z. Gleizer, Y. Hadas and Ya. E. Krasik, Europhysics Lett. 82, 55001 (2008).</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/2014PhPl...21f0701G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhPl...21f0701G"><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://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gillman, Eric D.; Amatucci, W. E.</p> <p>2014-06-01</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/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://ntrs.nasa.gov/search.jsp?R=19850041180&hterms=NTS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DNTS','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850041180&hterms=NTS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DNTS"><span id="translatedtitle">Electric fields in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and <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>Pedersen, A.; Knott, K.; Cattell, C. A.; Mozer, F. S.; Falthammar, C.-G.; Lindqvist, P.-A.; Manka, R. H.</p> <p>1985-01-01</p> <p>Results obtained by Forbes et al. (1981) on the basis of time delay measurements between ISEE 1 and ISEE 2 imply that the <span class="hlt">plasma</span> flow and the boundary contracting velocity were nearly the same, whereas the expanding boundary velocity was not accompanied by any significant <span class="hlt">plasma</span> <span class="hlt">sheet</span> <span class="hlt">plasma</span> motion. In the present study, this observation is discussed in conjunction with electric field data. The study is based on electric field data from the spherical double probe experiment on ISEE 1. Electric field data from GEOS 2 are used to some extent to monitor the electric fields near the geostationary orbit during the considered eve nts. Electric field data during CDAW 6 events are discussed, taking into account positions of ISEE 1/ISEE 2 and GEOS 2; March 22, 0600-1300 UT; and March 22, UT; and March 31, 1400-2400 UT.</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> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009EGUGA..11.8968P&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009EGUGA..11.8968P&link_type=ABSTRACT"><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://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://ntrs.nasa.gov/search.jsp?R=19900029440&hterms=spectrum+analyzer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dspectrum%2Banalyzer','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900029440&hterms=spectrum+analyzer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dspectrum%2Banalyzer"><span id="translatedtitle">Average electric wave spectra across the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and their relation to ion bulk speed</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Baumjohann, W.; Treumann, R. A.; Labelle, J.; Anderson, R. R.</p> <p>1989-01-01</p> <p>Using 4 months of tail data obtained by the ELF/MF spectrum analyzer of the wave experiment and the three-dimensional <span class="hlt">plasma</span> instrument on board the AMPTE/IRM satellite, a statistical survey on the electric wave spectral density in the earth's <span class="hlt">plasma</span> <span class="hlt">sheet</span> has been conducted. More than 50,000 10-s-averaged electric wave spectra were analyzed with respect to differences between their values in the inner and outer central <span class="hlt">plasma</span> <span class="hlt">sheet</span> and the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer as well as their dependence on radial distance and ion bulk speed. High-speed flows are dominated by broadband electrostatic noise with highest spectral densities in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary, where broadband electrostatic noise also exists during periods of low-speed flows. The broadband electrostatic noise has a typical spectral index of about -2. During low-speed flows the spectra in the central <span class="hlt">plasma</span> <span class="hlt">sheet</span> show distinct emissions at the <span class="hlt">electron</span> cyclotron odd half-harmonic and upper hybrid frequency. Wave intensities during episodes of fast perpendicular flows are higher than those associated with fast parallel flows.</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/2013EGUGA..15.2000D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.2000D"><span id="translatedtitle"><span class="hlt">Plasma</span> <span class="hlt">sheets</span> in induced magnetospheres of Mars and Venus</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dubinin, Eduard; Fraenz, Markus; Woch, Joahim; Zhang, Tielong; Wei, Yong; Fedorov, Andrei; Barabash, Stas; Lundin, Rickard</p> <p>2013-04-01</p> <p>Mars and Venus have no a global intrinsic field and solar wind interacts directly with their conductive ionospheric shells producing the induced magnetospheres with magnetic tails. <span class="hlt">Plasma</span> <span class="hlt">sheet</span> is the region in the tail where the magnetic field tensions transfer the momentum back to the ionospheric <span class="hlt">plasmas</span> which escape the planets. It is one of the main loss channels for the planetary ions. Mars Express and Venus Express have provided a wealth of the data on properties of the induced magnetic tails and <span class="hlt">plasma</span> <span class="hlt">sheets</span>. We will discuss their main characteristics including mechanisms of ion energization and their control by solar wind and the interplanetary magnetic field variations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1990ITED...37..840M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1990ITED...37..840M"><span id="translatedtitle">Design principles for a <span class="hlt">sheet</span>-beam <span class="hlt">electron</span> gun for a quasi-optical gyrotron</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Manheimer, Wallace M.; Fliflet, Arne W.; Lee, Robert</p> <p>1990-03-01</p> <p>The design considerations for a magnetized <span class="hlt">sheet</span> beam for which the <span class="hlt">electrons</span> have energy both perpendicular and parallel to the magnetic field are examined, including the basic design principles and scaling laws, the issue of orbit crossing and electrode synthesis in a <span class="hlt">sheet</span> beam configuration, limiting currents both in the guide tube and across the resonator, and the edge effects and their reduction or elimination by the use of edge focusing electrodes. The application envisioned for the <span class="hlt">sheet</span> beam is the driving of a quasi-optical gyrotron for <span class="hlt">electron</span> cyclotron resonance heating and current drive in fusion <span class="hlt">plasmas</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014JPhD...47L5501T&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014JPhD...47L5501T&link_type=ABSTRACT"><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://adsabs.harvard.edu/abs/2016PhPl...23i2901A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhPl...23i2901A"><span id="translatedtitle">Effects of <span class="hlt">electron</span> pressure anisotropy on current <span class="hlt">sheet</span> configuration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Artemyev, A. V.; Vasko, I. Y.; Angelopoulos, V.; Runov, A.</p> <p>2016-09-01</p> <p>Recent spacecraft observations in the Earth's magnetosphere have demonstrated that the magnetotail current <span class="hlt">sheet</span> can be supported by currents of anisotropic <span class="hlt">electron</span> population. Strong <span class="hlt">electron</span> currents are responsible for the formation of very thin (intense) current <span class="hlt">sheets</span> playing the crucial role in stability of the Earth's magnetotail. We explore the properties of such thin current <span class="hlt">sheets</span> with hot isotropic ions and cold anisotropic <span class="hlt">electrons</span>. Decoupling of the motions of ions and <span class="hlt">electrons</span> results in the generation of a polarization electric field. The distribution of the corresponding scalar potential is derived from the <span class="hlt">electron</span> pressure balance and the quasi-neutrality condition. We find that <span class="hlt">electron</span> pressure anisotropy is partially balanced by a field-aligned component of this polarization electric field. We propose a 2D model that describes a thin current <span class="hlt">sheet</span> supported by currents of anisotropic <span class="hlt">electrons</span> embedded in an ion-dominated current <span class="hlt">sheet</span>. Current density profiles in our model agree well with THEMIS observations in the Earth's magnetotail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19980237410&hterms=ion+activity+coefficient&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dion%2Bactivity%2Bcoefficient','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19980237410&hterms=ion+activity+coefficient&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dion%2Bactivity%2Bcoefficient"><span id="translatedtitle">Central <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> Ion Properties as Inferred from Ionospheric Observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wing, Simon; Newell, Patrick T.</p> <p>1998-01-01</p> <p>A method of inferring central <span class="hlt">plasma</span> <span class="hlt">sheet</span> (CPS) temperature, density, and pressure from ionospheric observations is developed. The advantage of this method over in situ measurements is that the CPS can be studied in its entirely, rather than only in fragments. As a result, for the first time, comprehensive two-dimensional equatorial maps of CPS pressure, density, and temperature within the isotropic <span class="hlt">plasma</span> <span class="hlt">sheet</span> are produced. These particle properties are calculated from data taken by the Special Sensor for Precipitating Particles, version 4 (SSJ4) particle instruments onboard DMSP F8, F9, F10, and F11 satellites during the entire year of 1992. Ion spectra occurring in conjunction with <span class="hlt">electron</span> acceleration events are specifically excluded. Because of the variability of magnetotail stretching, the mapping to the <span class="hlt">plasma</span> <span class="hlt">sheet</span> is done using a modified Tsyganenko [1989] magnetic field model (T89) adjusted to agree with the actual magnetotail stretch at observation time. The latter is inferred with a high degree of accuracy (correlation coefficient -0.9) from the latitude of the DMSP b2i boundary (equivalent to the ion isotropy boundary). The results show that temperature, pressure, and density all exhibit dawn-dusk asymmetries unresolved with previous measurements. The ion temperature peaks near the midnight meridian. This peak, which has been associated with bursty bulk flow events, widens in the Y direction with increased activity. The temperature is higher at dusk than at dawn, and this asymmetry increases with decreasing distance from the Earth. In contrast, the density is higher at dawn than at dusk, and there appears to be a density enhancement in the low-latitude boundary layer regions which increases with decreasing magnetic activity. In the near-Earth regions, the pressure is higher at dusk than at dawn, but this asymmetry weakens with increasing distance from the Earth and may even reverse so that at distances X less than approx. 10 to -12 R(sub E</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950046666&hterms=fluid+flow+tube&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dfluid%2Bflow%2Btube','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950046666&hterms=fluid+flow+tube&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dfluid%2Bflow%2Btube"><span id="translatedtitle">Interpretation of high-speed flows 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>Chen, C. X.; Wolf, R. A.</p> <p>1993-01-01</p> <p>Pursuing an idea suggested by Pontius and Wolf (1990), we propose that the `bursty bulk flows' observed by Baumjohann et al. (1990) and Angelopoulos et al. (1992) are `bubbles' in the Earth's <span class="hlt">plasma</span> <span class="hlt">sheet</span>. Specifically, they are flux tubes that have lower values of pV(exp 5/3) than their neighbors, where p is the thermal pressure of the particles and V is the volume of a tube containing one unit of magnetic flux. Whether they are created by reconnection or some other mechanism, the bubbles are propelled earthward by a magnetic buoyancy force, which is related to the interchange instability. Most of the major observed characteristics of the bursty bulk flows can be interpreted naturally in terms of the bubble picture. We propose a new `stratified fluid' picture of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, based on the idea that bubbles constitute the crucial transport mechanism. Results from simple mathematical models of <span class="hlt">plasma</span> <span class="hlt">sheet</span> transport support the idea that bubbles can resolve the pressure balance inconsistency, particularly in cases where <span class="hlt">plasma</span> <span class="hlt">sheet</span> ions are lost by gradient/curvature drift out the sides of the tail or bubbles are generated by reconnection in the middle of <span class="hlt">plasma</span> <span class="hlt">sheet</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMSM42A..03M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMSM42A..03M&link_type=ABSTRACT"><span id="translatedtitle">Features of the Active Evening <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> from MMS</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moore, T. E.; Chandler, M. O.; Avanov, L. A.; Burch, J. L.; Coffey, V. N.; Ergun, R. E.; Fuselier, S. A.; Gershman, D. J.; Giles, B. L.; Lavraud, B.; MacDonald, E.; Mauk, B.; Mukai, T.; Nakamura, R.; Pollock, C. J.; Russell, C. T.; Saito, Y.; Sauvaud, J. A.; Torbert, R. B.; Yokota, S.</p> <p>2015-12-01</p> <p>The Magnetospheric Multiscale (MMS) mission, consisting of four identical <span class="hlt">plasmas</span> and fields observatories, was launched into a 12 RE elliptical equatorial orbit in March 2015 and was in the process of being commissioned through August 2015. During commissioning, the orbit apogee rotated from near midnight through the evening toward the dusk sector and occasionally captured new observations of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, its boundary layers, and the magnetospheric tail lobes. On 22-23 June, an especially active <span class="hlt">plasma</span> <span class="hlt">sheet</span> was involved in a major geospace storm that developed a ring current with 200 nT DST. We report on the ion kinetic and flow features of this active <span class="hlt">plasma</span> <span class="hlt">sheet</span>, comparing them with familiar observations from earlier missions, as an exercise in validating the MMS observations and assessing their capabilities to provide higher time resolution in multi-point views of thin, fast-moving structures. The observed features include but are not limited to cold lobal wind streams in the lobes, tailward flowing auroral beams and conics, hot earthward field-aligned flows and counter-flows, fast cross-field convection of some flows toward the neutral <span class="hlt">sheet</span>, and the hot isotropic <span class="hlt">plasma</span> <span class="hlt">sheet</span> proper. Relationships between these features, the ionosphere, and the reconnecting magnetotail will be explored and discussed, seeking preliminary conclusions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995JGR...100.1857E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995JGR...100.1857E"><span id="translatedtitle">Nature and location of the source of <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer ion beams</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.; Onsager, T. G.; Thomsen, M. F.; Gosling, J. T.</p> <p>1995-02-01</p> <p>Onsager et al. (1991) have put forward a model of the formation of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer (PSBL) which relies on a steady source of <span class="hlt">plasma</span> from a spatially extended <span class="hlt">plasma</span> <span class="hlt">sheet</span>, together with steady equatorward and earthward ExB convection of field lines due to reconnection at a downtail neutral line. This model is a synthesis of earlier proposals and it explains such features as an <span class="hlt">electron</span> layer exterior to the ion boundary layer, ion velocity dispersion, counter streaming beams, low-speed cutoffs in the beams. It also explains the apparent evolution of the ion beams through 'kidney bean' shaped velocity-space distributions toward quasi-isotropic shells without invoking pitch angle scattering or energy diffusion. In this paper we explore two ramifications of the model. In principle we can map, as a function of time, the downtail neutral line distance and establish whether or not it is retreating during substorm recovery. We can also reconstruct the <span class="hlt">plasma</span> distribution function near the neutral line to see if it is most consistent with mantle or <span class="hlt">plasma</span> <span class="hlt">sheet</span> <span class="hlt">plasma</span>. We perform this analysis using International Sun Earth Explorer (ISEE) Fast <span class="hlt">Plasma</span> Experiment (FPE) data for two <span class="hlt">plasma</span> <span class="hlt">sheet</span> recovery events, one on March 1, 1978, and the other on April 18, 1978. On March 1, 1978, we find evidence for an initial retreat from around 110 to 160 R(sub E) in the first 15 min; little further retreat occurs thereafter. On April 18, 1978, the neutral line location ranges from as little as 40 R(sub E) tailward of the satellite to as much as 200 R(sub E), but there is no evidence for a systematic retreat. The reconstructed ion distributions for these events are most consistent with a <span class="hlt">plasma</span> <span class="hlt">sheet</span> origin for the March 1 case and possibly <span class="hlt">plasma</span> mantle or low-latitude boundary layer for the April 18 case.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950046223&hterms=kidney+beans&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dkidney%2Bbeans','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950046223&hterms=kidney+beans&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dkidney%2Bbeans"><span id="translatedtitle">Nature and location of the source of <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer ion beams</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Elphic, R. C.; Onsager, T. G.; Thomsen, M. F.; Gosling, J. T.</p> <p>1995-01-01</p> <p>Onsager et al. (1991) have put forward a model of the formation of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer (PSBL) which relies on a steady source of <span class="hlt">plasma</span> from a spatially extended <span class="hlt">plasma</span> <span class="hlt">sheet</span>, together with steady equatorward and earthward ExB convection of field lines due to reconnection at a downtail neutral line. This model is a synthesis of earlier proposals and it explains such features as an <span class="hlt">electron</span> layer exterior to the ion boundary layer, ion velocity dispersion, counter streaming beams, low-speed cutoffs in the beams. It also explains the apparent evolution of the ion beams through 'kidney bean' shaped velocity-space distributions toward quasi-isotropic shells without invoking pitch angle scattering or energy diffusion. In this paper we explore two ramifications of the model. In principle we can map, as a function of time, the downtail neutral line distance and establish whether or not it is retreating during substorm recovery. We can also reconstruct the <span class="hlt">plasma</span> distribution function near the neutral line to see if it is most consistent with mantle or <span class="hlt">plasma</span> <span class="hlt">sheet</span> <span class="hlt">plasma</span>. We perform this analysis using International Sun Earth Explorer (ISEE) Fast <span class="hlt">Plasma</span> Experiment (FPE) data for two <span class="hlt">plasma</span> <span class="hlt">sheet</span> recovery events, one on March 1, 1978, and the other on April 18, 1978. On March 1, 1978, we find evidence for an initial retreat from around 110 to 160 R(sub E) in the first 15 min; little further retreat occurs thereafter. On April 18, 1978, the neutral line location ranges from as little as 40 R(sub E) tailward of the satellite to as much as 200 R(sub E), but there is no evidence for a systematic retreat. The reconstructed ion distributions for these events are most consistent with a <span class="hlt">plasma</span> <span class="hlt">sheet</span> origin for the March 1 case and possibly <span class="hlt">plasma</span> mantle or low-latitude boundary layer for the April 18 case.</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://www.osti.gov/scitech/servlets/purl/883513','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/883513"><span id="translatedtitle"><span class="hlt">Electron</span> Diffraction Experiments using Laser <span class="hlt">Plasma</span> <span class="hlt">Electrons</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fill, E E; Trushin, S; Tommasini, R; Bruch, R</p> <p>2005-09-07</p> <p>We demonstrate that <span class="hlt">electrons</span> emitted from a laser <span class="hlt">plasma</span> can be used to generate diffraction patterns in reflection and transmission. The <span class="hlt">electrons</span> are emitted in the direction of laser polarization with energies up to 100 keV. The broad <span class="hlt">electron</span> energy spectrum makes possible the generation of a ''streaked'' diffraction pattern which allows recording fast processes in a single run.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000JGR...10513029S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000JGR...10513029S&link_type=ABSTRACT"><span id="translatedtitle">Thin current <span class="hlt">sheet</span> embedded within a thicker <span class="hlt">plasma</span> <span class="hlt">sheet</span>: Self-consistent kinetic theory</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sitnov, M. I.; Zelenyi, L. M.; Malova, H. V.; Sharma, A. S.</p> <p>2000-06-01</p> <p>A self-consistent theory of thin current <span class="hlt">sheets</span>, where the magnetic field line tension is balanced by the ion inertia rather than by the pressure gradient, is presented. Assuming that ions are the main current carriers and their dynamics is quasi-adiabatic, the Maxwell-Vlasov equations are reduced to the nonlocal analogue of the Grad-Shafranov equation using a new set of integrals of motion, namely, the particle energy and the <span class="hlt">sheet</span> invariant of the quasi-adiabatic motion. It is shown that for a drifting Maxwellian distribution of ions outside the <span class="hlt">sheet</span> the equilibrium equation can be reduced in the limits of strong and weak anisotropy to universal equations that determine families of equilibria with similar profiles of the magnetic field. In the region Bn/B0<vT/vD<<1 (B0, Bn, vD, and vT are the magnetic fields outside the <span class="hlt">sheet</span> and close to its central plane, the ion drift velocity outside the <span class="hlt">sheet</span>, and the ion thermal velocity, respectively) the thickness of such similar profiles is of the order of (vT/vD)1/3ρ0, where ρ0 is the thermal ion gyroradius outside the <span class="hlt">sheet</span>. In the limit of weak anisotropy (vT/vD>>1) the self-consistent current <span class="hlt">sheet</span> equilibrium may also exist with no indications of the catastrophe reported earlier by Burkhart et al. [1992a]. On the contrary, it is found that in this limit the magnetic field profiles again become similar to each other with the characteristic thickness ~ρ0. The profiles of <span class="hlt">plasma</span> and current densities as well as the components of the pressure tensor are calculated for arbitrary ion anisotropy outside the <span class="hlt">sheet</span>. It is shown that the thin current <span class="hlt">sheet</span> for the equilibrium considered here is usually embedded into a much thicker <span class="hlt">plasma</span> <span class="hlt">sheet</span>. Moreover, in the case of weak anisotropy the perturbation of the <span class="hlt">plasma</span> density inside the <span class="hlt">sheet</span> is shown to be proportional to the parameter vD/vT, and as a result the electrostatic effects should be small, consistent with observations. This model of the thin current <span class="hlt">sheet</span></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://www.osti.gov/scitech/biblio/6691648','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6691648"><span id="translatedtitle">First operation of a wiggler-focused, <span class="hlt">sheet</span> beam free <span class="hlt">electron</span> laser amplifier</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Destler, W.W.; Cheng, S.; Zhang, Z.X.; Antonsen, T.M. Jr.; Granatstein, V.L.; Levush, B.; Rodgers, J. )</p> <p>1994-05-01</p> <p>A wiggler-focused, <span class="hlt">sheet</span> beam free <span class="hlt">electron</span> laser (FEL) amplifier utilizing a short-period wiggler magnet has been proposed as a millimeter-wave source for current profile modification and/or <span class="hlt">electron</span> cyclotron resonance heating of tokamak <span class="hlt">plasmas</span>. As proposed, such an amplifier would operate at a frequency of approximately 100--200 GHz with an output power of 1--10 MW CW. <span class="hlt">Electron</span> beam energy would be in the range 500--1000 keV. To test important aspects of this concept, an initial <span class="hlt">sheet</span> beam FEL amplifier experiment has been performed using a 1 mm[times]2 cm <span class="hlt">sheet</span> beam produced by a pulse line accelerator with a pulse duration of 100 ns. The 500--570 keV, 4--18 A <span class="hlt">sheet</span> beam is propagated through a 56 period uniform wiggler ([lambda][sub [ital w</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014IJMPS..3260339R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014IJMPS..3260339R"><span id="translatedtitle">Enhancement mechanism of H- production and suitable configurations for materials processing in a 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>Ramos, Henry J.; Villamayor, Michelle Marie S.; Mella, Aubrey Faith M.; Salamania, Janella Mae R.; Villanueva, Matthew Bryan P.; Viloan, Rommel Paulo B.</p> <p>2014-08-01</p> <p>A magnetized <span class="hlt">sheet</span> <span class="hlt">plasma</span> ion source was developed for steady state high density <span class="hlt">plasma</span> with strong density and high temperature gradients. This feature provides efficient formation of negative hydrogen (H-) ions over a wide beam extraction area through the <span class="hlt">electron</span> volume process. A hexapole confinement at the cathode, addition of argon and magnesium seeding led to the increase of H- yield. The device configuration is suitable for <span class="hlt">plasma</span> based materials processing namely, synthesis of TiN, SiH, SnO2, and the formation of advanced MAX phase materials Ti2AlC, Ti2CdC and NbAlC.</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=19830050312&hterms=electrostatic+waves&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Delectrostatic%2Bwaves','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19830050312&hterms=electrostatic+waves&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Delectrostatic%2Bwaves"><span id="translatedtitle">Excitation of an electrostatic wave by a cold <span class="hlt">electron</span> current <span class="hlt">sheet</span> of finite thickness</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hwang, K. S.; Fontheim, E. G.; Ong, R. S. B.</p> <p>1983-01-01</p> <p>Calculations for the threshold of current-driven instabilities and the growth rates of ion acoustic and electrostatic ion cyclotron instabilities in a magnetized <span class="hlt">plasma</span> driven a current <span class="hlt">sheet</span> with a finite width are presented. Maxwellian equations are employed to model the velocity distributions of <span class="hlt">electrons</span> and ions in a direction perpendicular to the <span class="hlt">sheet</span>. A dispersion relation is defined for the regions of instability, and boundary conditions are characterized in order to obtain a set of eigenvalue equations. Thresholds are delineated for various regions, including ducted mode solutions where only ion-acoustic waves are excited in areas where the frequency range significantly exceeds the ion cyclotron frequency. When a constant <span class="hlt">electron</span> drift velocity is present, a thick current <span class="hlt">sheet</span> is more unstable than a thin one. Fewer modes become unstable with a thinner <span class="hlt">sheet</span>.</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://adsabs.harvard.edu/abs/2015JGRA..120..432M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120..432M"><span id="translatedtitle">On a possible connection between the longitudinally propagating near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> and auroral arc waves: A reexamination</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Motoba, T.; Ohtani, S.; Donovan, E. F.; Angelopoulos, V.</p> <p>2015-01-01</p> <p>propagating low-frequency waves (or wavy structures) often occur in a localized region of the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> and auroral arc immediately prior to auroral breakup. Although both are believed to be magnetospheric and ionospheric manifestations of a <span class="hlt">plasma</span> <span class="hlt">sheet</span> instability that may lead to substorm onset, the fundamental coupling processes behind their relationship are not yet understood. To address this question, we reexamined in detail a fortuitous conjunction event of prebreakup near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> and auroral arc waves, initially reported by Uritsky et al. (2009) using the Time History of Events and Macroscale Interactions during Substorms space-ground observations. The event exhibited a morphological one-to-one association between longitudinally propagating arc wave (LPAW) in the ionosphere and Pi2/Pc4 range wave activity in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. Our analysis revealed that (1) the LPAW was the periodic luminosity modulation of the growth phase arc by faint, diffuse, green line-dominated auroral patches propagating westward along/near the arc, rather than some type of small-scale arc structuring, such as auroral beads/rays/undulations; and (2) the <span class="hlt">plasma</span> <span class="hlt">sheet</span> wave, which had a diamagnetic nature, propagated duskward with accompanying coincident modulation of field-aligned fluxes of 0.1-30 keV <span class="hlt">electrons</span>. These findings suggest that the LPAW was likely connected to the <span class="hlt">plasma</span> <span class="hlt">sheet</span> wave via modulated diffuse precipitation of hard <span class="hlt">plasma</span> <span class="hlt">sheet</span> <span class="hlt">electrons</span> (> ~1 keV), not via filamentary field-aligned currents, as expected from the ballooning instability regime. Another potential implication is that such prebreakup low-frequency wave activity in the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> is not necessarily guaranteed to initiate prebreakup auroral arc structuring.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1996PSST....5..327W&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1996PSST....5..327W&link_type=ABSTRACT"><span id="translatedtitle">An ECR <span class="hlt">sheet</span> <span class="hlt">plasma</span> with a slot antenna and 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>Wakatsuchi, M.; Ishii, S.; Kato, Y.; Tani, F.; Sunagawa, M.</p> <p>1996-05-01</p> <p>A <span class="hlt">plasma</span> source is developed to create broad thin films. Instead of generating large <span class="hlt">plasmas</span>, substrates will be scrolled in uniform <span class="hlt">sheet</span> <span class="hlt">plasmas</span> to extend the process area. The <span class="hlt">plasmas</span> are generated by <span class="hlt">electron</span> cyclotron resonance; microwaves are radiated from a rectangular waveguide with a slot on its E-plane. This slot antenna is put between two permanent magnets. Their poles face each other so that a cusp field is formed in front of the slot. <span class="hlt">Plasmas</span> are generated with 0963-0252/5/2/031/img8 gas; <span class="hlt">plasma</span> parameters are measured by the Langmuir probe method and visible-range spectroscopy. The density uniformity is 9% within 20 cm length when a short plunger terminates the slot antenna. Spectra of 0963-0252/5/2/031/img9 bands and oxygen atomic lines are observed.</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/cgi-bin/nph-data_query?bibcode=2008AGUFMSM31B1718I&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008AGUFMSM31B1718I&link_type=ABSTRACT"><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://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> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFMSM23B0425V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFMSM23B0425V"><span id="translatedtitle">Laboratory Investigations of Current <span class="hlt">Sheets</span> at the <span class="hlt">Electron</span> Skin Depth Scale</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vincena, S.; Gekelman, W.</p> <p>2005-12-01</p> <p>Laboratory Investigations of Current <span class="hlt">Sheets</span> at the <span class="hlt">Electron</span> Skin Depth Scale. Theoretical investigations, in situ spacecraft and rocket missions, and laboratory studies form an essential triad for understanding the variety of current <span class="hlt">sheet</span> phenomena found in space <span class="hlt">plasmas</span>. In the Large <span class="hlt">Plasma</span> Device (LAPD) at UCLA, the formation dynamics, equilibrium state, and wave-mediated disruptions of current <span class="hlt">sheets</span> can be studied with great spatial and temporal resolution using a variety of probes as well as non-invasive laser induced fluorescence and other optical diagnostics. The LAPD is aptly suited for studying current <span class="hlt">sheets</span> flowing in a magnetized background <span class="hlt">plasma</span> which is capable of supporting Alfvén waves. The cylindrical device is 20m long and one meter in diameter with a solenoidal magnetic field as high as 3000 Gauss. For the parameters in this experiment, the <span class="hlt">plasma</span> column is ten shear Alfvén wavelengths along the field and 100 <span class="hlt">electron</span> inertial lengths (δe) (or 200 ρi) in the perpendicular direction. An <span class="hlt">electron</span> current <span class="hlt">sheet</span> is created in the <span class="hlt">plasma</span> by placing a thin copper plate in the <span class="hlt">plasma</span> column at one end of the device and pulsing this plate positive with respect to the chamber wall. The current <span class="hlt">sheet</span> extends for the length of the device and has an initial cross-field size of roughly 45 δe by 0.5δe. A parallel flow of ions is observed with similar dimensions and moves in the same direction as the <span class="hlt">electrons</span> in the current <span class="hlt">sheet</span> with a velocity of 0.2 times the ion sound speed. A much weaker sheared perpendicular flow is also measured. Cross-sections of the ion flow are measured at several axial locations over a distance of six meters. Second, as the ion flow increases in magnitude, a much broader (8ρi) density depletion (n=0.25nO) develops around the flow. The gradient scale length of the depletion shortens until the spontaneous growth of drift waves occurs. This disrupts the <span class="hlt">electron</span> current and ion flow, and leads to cross-field transport of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFMSM53A..08S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFMSM53A..08S&link_type=ABSTRACT"><span id="translatedtitle">Investigation of solar wind dependence of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> based on long-term Geotail/LEP data evaluation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saeki, R.; Seki, K.; Saito, Y.; Shinohara, I.; Miyashita, Y.; Imada, S.; Machida, S.</p> <p>2014-12-01</p> <p>It is observationally known that the <span class="hlt">plasma</span> density and temperature in <span class="hlt">plasma</span> <span class="hlt">sheet</span> are significantly changed by solar wind conditions [e.g., Terasawa et al., 1997]. Thus it is considered that the <span class="hlt">plasma</span> <span class="hlt">sheet</span> <span class="hlt">plasma</span> is originated from the solar wind, and several entry mechanisms have been suggested. When the interplanetary magnetic field (IMF) is southward, the solar wind <span class="hlt">plasma</span> enters the <span class="hlt">plasma</span> <span class="hlt">sheet</span> mainly through magnetic reconnection at the dayside magnetopause. In contrast, for the northward IMF, the double-lobe reconnection [Song et al., 1999], abnormal diffusion [Johnson and Cheng., 1997], and <span class="hlt">plasma</span> mixing through the Kelvin-Helmholtz instability caused by viscous interaction [Hasegawa et al., 2004] have been proposed. Relative contribution of each process is, however, far from understood. In the present study, we use magnetotail observations by the Geotail spacecraft at radial distances of 10-32 Re during 12-year period from 1995 to 2006 to investigate properties of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. We conducted a statistical analysis with calibrated LEP-EA [Mukai et al., 1994] ion and <span class="hlt">electron</span> data. We selected central <span class="hlt">plasma</span> <span class="hlt">sheet</span> observations and derived <span class="hlt">electron</span> and ion temperature and density using the same method and criteria as Terasawa et al. [1997]. In addition, OMNI solar-wind data are used. The results show that the <span class="hlt">plasma</span> <span class="hlt">sheet</span> density (both ion and <span class="hlt">electron</span> temperatures) has a good correlation with the solar wind density (kinetic energy) over the whole solar cycle. We find clear dawn-dusk asymmetry in the temperature ratio Ti/Te, i.e., the average Ti/Te is higher on the duskside than the dawn. The density also shows the dawn-dusk asymmetry and higher on the duskside than on the dawnside. A previous study by Wang et al. [2012] showed that Ti/Te is high (typically 5-10) in the magnetosheath. The statistical results, therefore, suggest that the shocked solar wind <span class="hlt">plasma</span> can easily enter the duskside <span class="hlt">plasma</span> <span class="hlt">sheet</span> rather than the dawnside. We will discuss the</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.osti.gov/scitech/biblio/22472206','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22472206"><span id="translatedtitle">Current <span class="hlt">sheet</span> in <span class="hlt">plasma</span> as a system with a controlling parameter</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fridman, Yu. A. Chukbar, K. V.</p> <p>2015-08-15</p> <p>A simple kinetic model describing stationary solutions with bifurcated and single-peaked current density profiles of a plane <span class="hlt">electron</span> beam or current <span class="hlt">sheet</span> in <span class="hlt">plasma</span> is presented. A connection is established between the two-dimensional constructions arising in terms of the model and the one-dimensional considerations by Bernstein−Greene−Kruskal facilitating the reconstruction of the distribution function of trapped particles when both the profile of the electric potential and the free particles distribution function are known.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMNG23A1481N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMNG23A1481N"><span id="translatedtitle">Thin current <span class="hlt">sheets</span> caused by <span class="hlt">plasma</span> flow gradients in 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>Nickeler, D.; Wiegelmann, T.</p> <p>2011-12-01</p> <p>To understand complex space <span class="hlt">plasma</span> systems like the solar wind-magnetosphere coupling, we need to have a good knowledge of the slowly evolving equilibrium state. The slow change of external constraints on the system (for example boundary conditions or other external parameters) lead in many cases to the formation of current <span class="hlt">sheets</span>. These current <span class="hlt">sheets</span> can trigger micro-instabilities, which cause resistivity on fluid scales. Consequently resistive instabilities like magnetic reconnection can occur and the systems evolves dynamically. Therefore such a picture of quasi-magneto-hydro-static changes can explain the quasy-static phase of many space <span class="hlt">plasma</span> before an eruption occurs. Within this work we extend the theory by the inclusion of a nonlinear stationary <span class="hlt">plasma</span> flows. Our analysis shows that stationary <span class="hlt">plasma</span> flows with strong flow gradients (for example the solar wind magnetosphere coupling) can be responsible for the existence or generation of current <span class="hlt">sheets</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015REDS..170..970Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015REDS..170..970Y"><span id="translatedtitle">Analysis of radiation performances of <span class="hlt">plasma</span> <span class="hlt">sheet</span> antenna</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yin, Bo; Zhang, Zu-Fan; Wang, Ping</p> <p>2015-12-01</p> <p>A novel concept of <span class="hlt">plasma</span> <span class="hlt">sheet</span> antennas is presented in this paper, and the radiation performances of <span class="hlt">plasma</span> <span class="hlt">sheet</span> antennas are investigated in detail. Firstly, a model of planar <span class="hlt">plasma</span> antenna (PPA) fed by a microstrip line is developed, and its reflection coefficient is computed by the JE convolution finite-difference time-domain method and compared with that of the metallic patch antenna. It is found that the design of PPA can learn from the theory of the metallic patch antenna, and the impedance matching and reconstruction of resonant frequency can be expediently realized by adjusting the parameters of <span class="hlt">plasma</span>. Then the PPA is mounted on a metallic cylindrical surface, and the reflection coefficient of the conformal <span class="hlt">plasma</span> antenna (CPA) is also computed. At the same time, the influence of conformal cylinder radius on the reflection coefficient is also analyzed. Finally, the radiation pattern of a CPA is given, the results show that the pattern agrees well with the one of PPA in the main radiation direction, but its side lobe level has deteriorated significantly.</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=19890056327&hterms=beam+diagnostics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dbeam%2Bdiagnostics','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19890056327&hterms=beam+diagnostics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dbeam%2Bdiagnostics"><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/2000GeoRL..27..851S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000GeoRL..27..851S"><span id="translatedtitle">Multiple-spacecraft observation of a narrow transient <span class="hlt">plasma</span> jet 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>Sergeev, V. A.; Sauvaud, J.-A.; Popescu, D.; Kovrazhkin, R. A.; Liou, K.; Newell, P. T.; Brittnacher, M.; Parks, G.; Nakamura, R.; Mukai, T.; Reeves, G. D.</p> <p>2000-03-01</p> <p>We use observations from five magnetospheric spacecraft in a fortuitous constellation to show that narrow transient <span class="hlt">plasma</span> flow jets of considerable length formed in the tail can intrude into the inner magnetosphere and provide considerable contribution to the total <span class="hlt">plasma</span> transport. A specific auroral structure, the auroral streamer, accompanied the development of this narrow <span class="hlt">plasma</span> jet. These observations support the ‘boiling’ <span class="hlt">plasma</span> <span class="hlt">sheet</span> model consisting of localized underpopulated <span class="hlt">plasma</span> tubes (bubbles) moving Earthward at high speeds as a realistic way to resolve the ‘convection crisis’ and to close the global magnetospheric circulation pattern.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRE..121..871B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRE..121..871B"><span id="translatedtitle">Survey of Galileo <span class="hlt">plasma</span> observations in Jupiter'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>Bagenal, Fran; Wilson, Robert J.; Siler, Scott; Paterson, William R.; Kurth, William S.</p> <p>2016-05-01</p> <p>The <span class="hlt">plasma</span> science (PLS) instrument on the Galileo spacecraft (orbiting Jupiter from December 1995 to September 2003) measured properties of the ions that were trapped in the magnetic field. The PLS data provide a survey of the <span class="hlt">plasma</span> properties between ~5 and 30 Jupiter radii (RJ) in the equatorial region. We present <span class="hlt">plasma</span> properties derived via two analysis methods: numerical moments and forward modeling. We find that the density decreases with radial distance by nearly 5 orders of magnitude from ~2 to 3000 cm-3 at 6 RJ to ~0.05 cm-3 at 30 RJ. The density profile did not show major changes from orbit to orbit, suggesting that the <span class="hlt">plasma</span> production and transport remained constant within about a factor of 2. The radial profile of ion temperature increased with distance which implied that contrary to the concept of adiabatic cooling on expansion, the <span class="hlt">plasma</span> heats up as it expands out from Io's orbit (where Ti ~ 60-80 eV) at ~6 RJ to a few keV at 30 RJ. There does not seem to be a long-term, systematic variation in ion temperature with either local time or longitude. This latter finding differs from earlier analysis of Galileo PLS data from a selection of orbits. Further examination of all data from all Galileo orbits suggests that System III variations are transitory on timescales of weeks, consistent with the modeling of Cassini Ultraviolet Imaging Spectrograph observations. The <span class="hlt">plasma</span> flow is dominated by azimuthal flow that is between 80% and 100% of corotation out to 25 RJ.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUSMSM31B..01M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUSMSM31B..01M"><span id="translatedtitle">Plume Contribution to the <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> and 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>Moore, T. E.; Fok, M. H.; Delcourt, D. C.; Slinker, S. P.; Fedder, J. A.</p> <p>2007-05-01</p> <p>We investigate the fate of plasmaspheric plumes to assess the resultant enhancement of <span class="hlt">plasma</span> <span class="hlt">sheet</span> and ring current pressure and compare with that for steady polar wind outflows. We use test particle motions in LFM global circulation model fields. The inner magnetosphere is simulated with the CRCM model of Fok and Wolf, including the Ober plasmasphere model. Global circulation is stimulated by a period of southward IMF embedded in a longer interval of northward IMF. This leads to the production of a realistic plasmaspheric plume, enhancing the <span class="hlt">plasma</span> density on the dayside. Large numbers of test particles are launched with the properties of plasmaspheric ions on the L=8 shell, and weighted by densities as specified by the Ober model, as it responds to enhanced convection. Particles are tracked until they are lost from the system downstream or into the atmosphere, using the full equations of motion as implemented in the Delcourt code. Results are compared with earlier computations for polar wind outflows from the region above 55 deg. latitude. The plume produces an enhanced cloud of polar wind like <span class="hlt">plasma</span> that flows through the polar caps and lobes, entering the <span class="hlt">plasma</span> <span class="hlt">sheet</span> reconnection region and splitting into earthward and tailward flows. We assess the magnitude and duration of the resultant pressure enhancement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/14728558','PUBMED'); return false;" href="https://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="https://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.</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/1993JGR....98.3999H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993JGR....98.3999H"><span id="translatedtitle">The Uranian corona as a charge exchange cascade of <span class="hlt">plasma</span> <span class="hlt">sheet</span> protons</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Herbert, F.</p> <p>1993-03-01</p> <p>The paper uses models of magnetic convection and interparticle interactions to examine the collisional interactions between atmospheric neutral hydrogen and magnetospheric charged particles observed by Voyager to be convecting through the Uranian magnetosphere. The e(-)-H collisional ionization process, continually reenergized by compressional heating of the <span class="hlt">electrons</span> as they drift toward Uranus, produces a cascade of new <span class="hlt">plasma</span>. This process has been suggested elsewhere as the source of the warm (10 eV at L = 5) <span class="hlt">plasma</span> and is found in the present study to continue in a cascade to even cooler and more abundant <span class="hlt">plasma</span>. This newly created <span class="hlt">plasma</span> consists almost entirely of <span class="hlt">electrons</span> and protons because He and H2 are nearly absent from the uppermost layers of the atmosphere. If this <span class="hlt">plasma</span> crosses the dayside magnetopause and mixes with magnetopause boundary layers such as the <span class="hlt">plasma</span> mantle, there to be swept back along the magnetotail, reincorporated into the magnetotail by the same processes postulated for solar wind <span class="hlt">plasma</span> entry, and reenergized in the magnetotail current <span class="hlt">sheet</span>, it would constitute an important source for the hot <span class="hlt">plasma</span> observed by Voyager.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..121.5510Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..121.5510Y"><span id="translatedtitle">Propagation of small size magnetic holes in the magnetospheric <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>Yao, S. T.; Shi, Q. Q.; Li, Z. Y.; Wang, X. G.; Tian, A. M.; Sun, W. J.; Hamrin, M.; Wang, M. M.; Pitkänen, T.; Bai, S. C.; Shen, X. C.; Ji, X. F.; Pokhotelov, D.; Yao, Z. H.; Xiao, T.; Pu, Z. Y.; Fu, S. Y.; Zong, Q. G.; De Spiegeleer, A.; Liu, W.; Zhang, H.; Rème, H.</p> <p>2016-06-01</p> <p>Magnetic holes (MHs), characteristic structures where the magnetic field magnitude decreases significantly, have been frequently observed in space <span class="hlt">plasmas</span>. Particularly, small size magnetic holes (SSMHs) which the scale is less than or close to the proton gyroradius are recently detected in the magnetospheric <span class="hlt">plasma</span> <span class="hlt">sheet</span>. In this study of Cluster observations, by the timing method, the minimum directional difference (MDD) method, and the spatiotemporal difference (STD) method, we obtain the propagation velocity of SSMHs in the <span class="hlt">plasma</span> flow frame. Furthermore, based on <span class="hlt">electron</span> magnetohydrodynamics (EMHD) theory we calculate the velocity, width, and depth of the <span class="hlt">electron</span> solitary wave and compare it to SSMH observations. The result shows a good accord between the theory and the observation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010APS..MARD20004S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010APS..MARD20004S"><span id="translatedtitle"><span class="hlt">Electronic</span> and magnetic properties of functionalized BN <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>Sun, Qiang; Zhou, Jian; Wang, Qian; Jena, Puru</p> <p>2010-03-01</p> <p>First principles calculations based on density functional theory reveal some unusual properties of BN <span class="hlt">sheet</span> functionalized with hydrogen and fluorine. These properties differ from those of similarly functionalized graphene even though both share the same honeycomb structure. (1) Unlike graphene which undergoes a metal to insulator transition when fully hydrogenated, the band gap of the BN <span class="hlt">sheet</span> significantly narrows when fully saturated with hydrogen. Furthermore, the band gap of the BN <span class="hlt">sheet</span> can be tuned from 4.7 eV to 0.6 eV and the system can be a direct or an indirect semiconductor or even a half-metal depending upon surface coverage. (2) Unlike graphene, BN <span class="hlt">sheet</span>, due to its hetero-atomic composition, permits the surface to be co-decorated with H and F, thus leading to anisotropic structures with rich <span class="hlt">electronic</span> and magnetic properties. (3) Unlike graphene, BN <span class="hlt">sheets</span> can be made ferromagnetic, antiferromagnetic, or magnetically degenerate depending upon how the surface is functionalized. (4) Unlike graphene, the stability of magnetic coupling of functionalized BN <span class="hlt">sheet</span> can be modulated by applying external strain. Our study highlights the potential of functionalized BN <span class="hlt">sheets</span> for novel applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM42A..04J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM42A..04J"><span id="translatedtitle">Role of <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> Source Population in Ring Current Dynamics (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jordanova, V.; Yu, Y.; Reeves, G. D.; Kletzing, C.; Spence, H.; Sazykin, S. Y.</p> <p>2013-12-01</p> <p>Understanding the dynamics of ring current particles during disturbed conditions remains a long-standing challenge, moreover these particles represent a seed population for the hazardous radiation belts. The formation of the storm-time ring current depends on two main factors: 1) the <span class="hlt">plasma</span> <span class="hlt">sheet</span> as a reservoir supplying particles that are transported earthward, and 2) the electric field as a mechanism that energizes them. To investigate ring current development on a global scale, we use our four-dimensional (4-D) ring current-atmosphere interactions model (RAM-SCB) [Jordanova et al., 2010; Zaharia et al., 2010] which solves the kinetic equation for H+, O+, and He+ ions and <span class="hlt">electrons</span> using a self-consistently calculated magnetic field in force balance with the anisotropic ring current <span class="hlt">plasma</span> pressure. The model boundary was recently expanded from geosynchronous orbit to 9 RE, where the <span class="hlt">plasma</span> boundary conditions are specified from the empirical <span class="hlt">plasma</span> <span class="hlt">sheet</span> model TM03 [Tsyganenko and Mukai, 2003] based on Geotail data. We simulate the transport, acceleration, and loss of energetic particles from the magnetotail to the inner magnetosphere during several geomagnetic storms that occurred since the launch of the Van Allen Probes in August 2012. We compare our results with simultaneous <span class="hlt">plasma</span> and field observations from the Energetic particle, Composition, and Thermal <span class="hlt">plasma</span> (ECT) [Spence et al., 2013] and the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) [Kletzing et al., 2013] investigations on the Van Allen Probes. We investigate the role of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> source population in global ring current simulations considering various boundary conditions and electric field formulations. An improved understanding of the highly coupled inner magnetosphere system is provided.</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> </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('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4459207','PMC'); return false;" href="https://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/2014GeoRL..41.8713F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014GeoRL..41.8713F"><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://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</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>2014-12-01</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.</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; Büchner, Jörg</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://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/2005JPhA...38.2997B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005JPhA...38.2997B"><span id="translatedtitle">Casimir effects for a flat <span class="hlt">plasma</span> <span class="hlt">sheet</span>: I. Energies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barton, G.</p> <p>2005-04-01</p> <p>We study a fluid model of an infinitesimally thin <span class="hlt">plasma</span> <span class="hlt">sheet</span> occupying the xy plane, loosely imitating a single base plane from graphite. In terms of the fluid charge e/a2 and mass m/a2 per unit area, the crucial parameters are q ⋡ 2πe2/mc2a2, a Debye-type cutoff K\\equiv \\sqrt{4\\pi }/a on surface-parallel normal-mode wavenumbers k, and X ⋡ K/q. The cohesive energy β per unit area is determined from the zero-point energies of the exact normal modes of the <span class="hlt">plasma</span> coupled to the Maxwell field, namely TE and TM photon modes, plus bound modes decaying exponentially with |z|. Odd-parity modes (with Ex,y(z = 0) = 0) are unaffected by the <span class="hlt">sheet</span> except for their overall phases, and are irrelevant to β, although the following paper shows that they are essential to the fields (e.g. to their vacuum expectation values), and to the stresses on the <span class="hlt">sheet</span>. Realistically one has X Gt 1, the result β ~ planckcq1/2K5/2 is nonrelativistic, and it comes from the surface modes. By contrast, X Lt 1 (nearing the limit of perfect reflection) would entail β ~ -planckcqK2log(1/X): contrary to folklore, the surface energy of perfect reflectors is divergent rather than zero. An appendix spells out the relation, for given k, between bound modes and photon phase-shifts. It is very different from Levinson's theorem for 1D potential theory: cursory analogies between TM and potential scattering are apt to mislead.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoRL..43.4841N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoRL..43.4841N"><span id="translatedtitle">Transient, small-scale field-aligned currents in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer during storm time substorms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nakamura, R.; Sergeev, V. A.; Baumjohann, W.; Plaschke, F.; Magnes, W.; Fischer, D.; Varsani, A.; Schmid, D.; Nakamura, T. K. M.; Russell, C. T.; Strangeway, R. J.; Leinweber, H. K.; Le, G.; Bromund, K. R.; Pollock, C. J.; Giles, B. L.; Dorelli, J. C.; Gershman, D. J.; Paterson, W.; Avanov, L. A.; Fuselier, S. A.; Genestreti, K.; Burch, J. L.; Torbert, R. B.; Chutter, M.; Argall, M. R.; Anderson, B. J.; Lindqvist, P.-A.; Marklund, G. T.; Khotyaintsev, Y. V.; Mauk, B. H.; Cohen, I. J.; Baker, D. N.; Jaynes, A. N.; Ergun, R. E.; Singer, H. J.; Slavin, J. A.; Kepko, E. L.; Moore, T. E.; Lavraud, B.; Coffey, V.; Saito, Y.</p> <p>2016-05-01</p> <p>We report on field-aligned current observations by the four Magnetospheric Multiscale (MMS) spacecraft near the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer (PSBL) during two major substorms on 23 June 2015. Small-scale field-aligned currents were found embedded in fluctuating PSBL flux tubes near the separatrix region. We resolve, for the first time, short-lived earthward (downward) intense field-aligned current <span class="hlt">sheets</span> with thicknesses of a few tens of kilometers, which are well below the ion scale, on flux tubes moving equatorward/earthward during outward <span class="hlt">plasma</span> <span class="hlt">sheet</span> expansion. They coincide with upward field-aligned <span class="hlt">electron</span> beams with energies of a few hundred eV. These <span class="hlt">electrons</span> are most likely due to acceleration associated with a reconnection jet or high-energy ion beam-produced disturbances. The observations highlight coupling of multiscale processes in PSBL as a consequence of magnetotail reconnection.</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/cgi-bin/nph-data_query?bibcode=2015PhRvS..18h1304W&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015PhRvS..18h1304W&link_type=ABSTRACT"><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://www.ncbi.nlm.nih.gov/pubmed/24266197','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24266197"><span id="translatedtitle"><span class="hlt">Plasma</span> treatment of thin film coated with graphene flakes for the reduction of <span class="hlt">sheet</span> resistance.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kim, Sung Hee; Oh, Jong Sik; Kim, Kyong Nam; Seo, Jin Seok; Jeon, Min Hwan; Yang, Kyung Chae; Yeom, Geun Young</p> <p>2013-12-01</p> <p>We investigated the effects of <span class="hlt">plasma</span> treatment on the <span class="hlt">sheet</span> resistance of thin films spray-coated with graphene flakes on polyethylene terephthalate (PET) substrates. Thin films coated with graphene flakes show high <span class="hlt">sheet</span> resistance due to defects within graphene edges, domains, and residual oxygen content. Cl2 <span class="hlt">plasma</span> treatment led to decreased <span class="hlt">sheet</span> resistance when treatment time was increased, but when thin films were treated for too long the <span class="hlt">sheet</span> resistance increased again. Optimum treatment time was related to film thickness. The reduction of <span class="hlt">sheet</span> resistance may be explained by the donation of holes due to forming pi-type covalent bonds of Cl with carbon atoms on graphene surfaces, or by C--Cl bonding at the sites of graphene defects. However, due to radiation damage caused by <span class="hlt">plasma</span> treatment, <span class="hlt">sheet</span> resistance increased with increased treatment time. We found that the <span class="hlt">sheet</span> resistance of PET film coated with graphene flakes could be decreased by 50% under optimum conditions. PMID:24266197</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22047453','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22047453"><span id="translatedtitle">Energy efficiency of <span class="hlt">electron</span> <span class="hlt">plasma</span> emitters</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zalesski, V. G.</p> <p>2011-12-15</p> <p><span class="hlt">Electron</span> emission influence from gas-discharge <span class="hlt">plasma</span> on <span class="hlt">plasma</span> emitter energy parameters is considered. It is shown, that <span class="hlt">electron</span> emission from <span class="hlt">plasma</span> is accompanied by energy contribution redistribution in the gas-discharge from <span class="hlt">plasma</span> emitter supplies sources-the gas-discharge power supply and the accelerating voltage power supply. Some modes of <span class="hlt">electron</span> emission as a result can be realized: 'a probe measurements mode,' 'a transitive mode,' and 'a full switching mode.'.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22493753','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22493753"><span id="translatedtitle">Current <span class="hlt">sheets</span> with inhomogeneous <span class="hlt">plasma</span> temperature: Effects of polarization electric field and 2D solutions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Catapano, F. Zimbardo, G.; Artemyev, A. V. Vasko, I. Y.</p> <p>2015-09-15</p> <p>We develop current <span class="hlt">sheet</span> models which allow to regulate the level of <span class="hlt">plasma</span> temperature and density inhomogeneities across the <span class="hlt">sheet</span>. These models generalize the classical Harris model via including two current-carrying <span class="hlt">plasma</span> populations with different temperature and the background <span class="hlt">plasma</span> not contributing to the current density. The parameters of these <span class="hlt">plasma</span> populations allow regulating contributions of <span class="hlt">plasma</span> density and temperature to the pressure balance. A brief comparison with spacecraft observations demonstrates the model applicability for describing the Earth magnetotail current <span class="hlt">sheet</span>. We also develop a two dimensional (2D) generalization of the proposed model. The interesting effect found for 2D models is the nonmonotonous profile (along the current <span class="hlt">sheet</span>) of the magnetic field component perpendicular to the current <span class="hlt">sheet</span>. Possible applications of the model are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25062198','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25062198"><span id="translatedtitle"><span class="hlt">Electron</span> <span class="hlt">plasma</span> orbits from competing diocotron drifts.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hurst, N C; Danielson, J R; Baker, C J; Surko, C M</p> <p>2014-07-11</p> <p>The perpendicular dynamics of a pure <span class="hlt">electron</span> <span class="hlt">plasma</span> column are investigated when the <span class="hlt">plasma</span> spans two Penning-Malmberg traps with noncoinciding axes. The <span class="hlt">plasma</span> executes noncircular orbits described by competing image-charge electric-field (diocotron) drifts from the two traps. A simple model is presented that predicts a set of nested orbits in agreement with observed <span class="hlt">plasma</span> trajectories.</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=19820033327&hterms=crossing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dcrossing','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19820033327&hterms=crossing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dcrossing"><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, thermal <span class="hlt">plasma</span>, and energetic particle data measured on the IMP 8 spacecraft are used to demonstrate that a thin <span class="hlt">plasma</span> <span class="hlt">sheet</span> with rapidly flowing <span class="hlt">plasma</span> undergoes violent oscillatory motion that causes the entire thickness of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> to pass over the spacecraft in times which are sometimes as short as 10 s. Ions with 50 and 290 keV energy are investigated since their gyroradii are comparable to the <span class="hlt">plasma</span> <span class="hlt">sheet</span> thickness. As the spacecraft moves from the <span class="hlt">plasma</span> <span class="hlt">sheet</span> into the lobe, the energetic particle intensities decrease, but the 290 keV ions are relatively more numerous than 50 keV ions on field lines located deeper in the lobe.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFMSH14A1691B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFMSH14A1691B"><span id="translatedtitle">Heliospheric current <span class="hlt">sheet</span> in the distant solar wind <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>Borovikov, S.; Pogorelov, N. V.; Zank, G. P.; Kryukov, I. A.</p> <p>2007-12-01</p> <p>Since Voyager 1 <span class="hlt">plasma</span> instrument is not operational, understanding the data obtained by its magnetometer is of great importance for heliospheric community. One of the main difficulties one encounters when modeling the interplanetary magnetic field (IMF) in the solar wind (SW) is the necessity of a very fine resolution of the heliospheric current <span class="hlt">sheet</span> (HCS). The angle between the Sun's rotation and magnetic-dipole axes is never zero, varying from about 8-9 degrees during solar minima to 90 degrees at solar maxima. As a result of Sun's rotation, the distance between two consecutive crossings of the ecliptic plane by the HCS becomes as small as about 3 AU in the supersonic SW and necessarily smaller in the inner heliosheath. As shown by Pogorelov (2006), charge exchange of the SW <span class="hlt">plasma</span> with the interstellar medium neutrals can affect the HCS behavior qualitatively. This study is an attempt to investigate the HCS evolution in the SW from its origin at the inner boundary of the computational region out into the heliosheath. Comparison is made of the ideal MHD and MHD-neutral solutions.</p> </li> <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://adsabs.harvard.edu/abs/2016SPIE.9782E..0JD','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SPIE.9782E..0JD"><span id="translatedtitle">Atomic precision etch using a low-<span class="hlt">electron</span> temperature <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>Dorf, L.; Wang, J.-C.; Rauf, S.; Zhang, Y.; Agarwal, A.; Kenney, J.; Ramaswamy, K.; Collins, K.</p> <p>2016-03-01</p> <p>Sub-nm precision is increasingly being required of many critical <span class="hlt">plasma</span> etching processes in the semiconductor industry. Accurate control over ion energy and ion/radical composition is needed during <span class="hlt">plasma</span> processing to meet these stringent requirements. Described in this work is a new <span class="hlt">plasma</span> etch system which has been designed with the requirements of atomic precision <span class="hlt">plasma</span> processing in mind. In this system, an <span class="hlt">electron</span> <span class="hlt">sheet</span> beam parallel to the substrate surface produces a <span class="hlt">plasma</span> with an order of magnitude lower <span class="hlt">electron</span> temperature Te (~ 0.3 eV) and ion energy Ei (< 3 eV without applied bias) compared to conventional radio-frequency (RF) <span class="hlt">plasma</span> technologies. <span class="hlt">Electron</span> beam <span class="hlt">plasmas</span> are characterized by higher ion-to-radical fraction compared to RF <span class="hlt">plasmas</span>, so a separate radical source is used to provide accurate control over relative ion and radical concentrations. Another important element in this <span class="hlt">plasma</span> system is low frequency RF bias capability which allows control of ion energy in the 2-50 eV range. Presented in this work are the results of etching of a variety of materials and structures performed in this system. In addition to high selectivity and low controllable etch rate, an important requirement of atomic precision etch processes is no (or minimal) damage to the remaining material surface. It has traditionally not been possible to avoid damage in RF <span class="hlt">plasma</span> processing systems, even during atomic layer etch. The experiments for Si etch in Cl2 based <span class="hlt">plasmas</span> in the aforementioned etch system show that damage can be minimized if the ion energy is kept below 10 eV. Layer-by-layer etch of Si is also demonstrated in this etch system using electrical and gas pulsing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012PlST...14....9D&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012PlST...14....9D&link_type=ABSTRACT"><span id="translatedtitle">The Interaction of C-Band Microwaves with Large <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>Ding, Liang; Huo, Wenqing; Yang, Xinjie; Xu, Yuemin</p> <p>2012-01-01</p> <p>A large <span class="hlt">plasma</span> <span class="hlt">sheet</span> 60 cm×60 cm×2 cm in size was generated using a hollow cathode, and measurements were conducted for interactions including transmission, reflection and absorption. With different discharge parameters, <span class="hlt">plasma</span> <span class="hlt">sheets</span> can vary and influence microwave strength. Microwave reflection decreases when the discharge current rises, and the opposite occurs in transmission. The C-band microwave is absorbed when it is propagated through large <span class="hlt">plasma</span> <span class="hlt">sheets</span> at higher pressure. When <span class="hlt">plasma</span> density and collision frequency are fitted with incident microwave frequency, a large amount of microwave energy is consumed. Reflection, transmission and absorption all exist simultaneously. <span class="hlt">Plasma</span> <span class="hlt">sheets</span> are an attractive alternative to microwave steering at low pressure, and the microwave reflection used in receiving radar can be altered by changing the discharge parameters.</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/1994hcds.rept.....C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994hcds.rept.....C"><span id="translatedtitle">High current density <span class="hlt">sheet</span>-like <span class="hlt">electron</span> beam generator</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chow-Miller, Cora; Korevaar, Eric; Schuster, John</p> <p></p> <p><span class="hlt">Sheet</span> <span class="hlt">electron</span> beams are very desirable for coupling to the evanescent waves in small millimeter wave slow-wave circuits to achieve higher powers. In particular, they are critical for operation of the free-<span class="hlt">electron</span>-laser-like Orotron. The program was a systematic effort to establish a solid technology base for such a <span class="hlt">sheet</span>-like <span class="hlt">electron</span> emitter system that will facilitate the detailed studies of beam propagation stability. Specifically, the effort involved the design and test of a novel <span class="hlt">electron</span> gun using Lanthanum hexaboride (LaB6) as the thermionic cathode material. Three sets of experiments were performed to measure beam propagation as a function of collector current, beam voltage, and heating power. The design demonstrated its reliability by delivering 386.5 hours of operation throughout the weeks of experimentation. In addition, the cathode survived two venting and pump down cycles without being poisoned or losing its emission characteristics. A current density of 10.7 A/sq cm. was measured while operating at 50 W of ohmic heating power. Preliminary results indicate that the nearby presence of a metal plate can stabilize the beam.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20957885','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20957885"><span id="translatedtitle">Dissipation in Turbulent <span class="hlt">Plasma</span> due to Reconnection in Thin Current <span class="hlt">Sheets</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sundkvist, David; Bale, Stuart D.; Retino, Alessandro; Vaivads, Andris</p> <p>2007-07-13</p> <p>We present in situ measurements in a space <span class="hlt">plasma</span> showing that thin current <span class="hlt">sheets</span> the size of an ion inertial length exist and are abundant in strong and intermittent <span class="hlt">plasma</span> turbulence. Many of these current <span class="hlt">sheets</span> exhibit the microphysical signatures of reconnection. The spatial scale where intermittency occurs corresponds to the observed structures. The reconnecting current <span class="hlt">sheets</span> represent a type of dissipation mechanism, with observed dissipation rates comparable to or even dominating over collisionless damping rates of waves at ion inertial length scales (x100), and can have far reaching implications for small-scale dissipation in all turbulent <span class="hlt">plasmas</span>.</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://adsabs.harvard.edu/abs/2010JGRA..11512225E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JGRA..11512225E"><span id="translatedtitle">Multiple harmonic ULF waves in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer observed by Cluster</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Engebretson, M. J.; Kahlstorf, C. R. G.; Posch, J. L.; Keiling, A.; Walsh, A. P.; Denton, R. E.; Broughton, M. C.; Owen, C. J.; FornaçOn, K.-H.; RèMe, H.</p> <p>2010-12-01</p> <p>The passage of the Cluster satellites in a polar orbit through Earth's magnetotail has provided numerous observations of harmonically related Pc 1-2 ULF wave events, with the fundamental near the local proton cyclotron frequency Ωcp. Broughton et al. (2008) reported observations by Cluster of three such events in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer, and used the wave telescope technique to determine that their wave vectors k were nearly perpendicular to B. This paper reports the results of a search for such waves throughout the 2003 Cluster tail passage. During the 4 month period of July-October 2003, 35 multiple-harmonic wave events were observed, all in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer (PSBL). From the first observed event (22 July) to the last (28 October), 13 of Cluster's 42 tail passes had at least one event. The wave events were rather evenly distributed from XGSE = -7 RE out to the Cluster apogee distance of -18 RE, with one event observed at -4 RE. ZGSE for these events ranged from -10 to -3 RE and +3 to +7 RE (i.e., there were no events for ∣Z∣ < 3 RE). The wave events, with durations from ˜1 to 50 min, were consistently associated with signatures of the PSBL: elevated fluxes of counterstreaming ions with energies ranging from ˜3 to 30 keV, and elevated fluxes of <span class="hlt">electrons</span> with energies ranging from 0.25 to ˜5 keV. Analysis of <span class="hlt">plasma</span> parameters suggests that although waves occurred only when the ion beta exceeded 0.1 (somewhat larger than typical for the PSBL), ion particle pressure may be of more physical importance in controlling wave occurrence. <span class="hlt">Electron</span> distributions were more isotropic in pitch angles than the ion distributions, but some evidence of counterstreaming <span class="hlt">electrons</span> was detected in 83% of the events. The ions also showed clear signatures of shell-like or ring-like distributions; i.e., with reduced fluxes below the energy of maximum flux. The suprathermal ion fluxes were asymmetric in all events studied, with more ions streaming earthward</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6712404','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6712404"><span id="translatedtitle">Mode-conversion induced tearing effects in a <span class="hlt">plasma</span> neutral <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kaw, P.K.; Sudan, R.N.</p> <p>1981-01-01</p> <p>A new collisionless dissipation mechanism which can drive tearing modes in a <span class="hlt">plasma</span> neutral <span class="hlt">sheet</span> is described. The new mechanism relies on the presence of a background cold <span class="hlt">plasma</span> which leads to mode conversion into a continuous spectrum of cold <span class="hlt">plasma</span> waves.</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/2016cosp...41E.624F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E.624F"><span id="translatedtitle">Destabilization of 2D magnetic current <span class="hlt">sheets</span> by resonance with bouncing <span class="hlt">electron</span> - a new theory</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fruit, Gabriel; Louarn, Philippe; Tur, Anatoly</p> <p>2016-07-01</p> <p>In the general context of understanding the possible destabilization of the magnetotail before a substorm, we propose a kinetic model for electromagnetic instabilities in resonant interaction with trapped bouncing <span class="hlt">electrons</span>. The geometry is clearly 2D and uses Harris <span class="hlt">sheet</span> profile. Fruit et al. 2013 already used this model to investigate the possibilities of electrostatic instabilities. Tur et al. 2014 generalizes 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 (a few seconds). 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 quasi neutrality condition and the Ampere's law for the current density. The present talk will focus on the main results of this theory. The electrostatic version of the model may be applied to the near-Earth environment (8-12 R_{E}) where beta is rather low. It is showed that inclusion of bouncing <span class="hlt">electron</span> motion may enhance strongly the growth rate of the classical drift wave instability. This model could thus explain the generation of strong parallel electric fields in the ionosphere and the formation of aurora beads with wavelength of a few hundreds of km. In the electromagnetic version, it is found that for mildly stretched current <span class="hlt">sheet</span> (B_{z} > 0.1 B _{lobes}) 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> 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_{z}/B _{lobes}, the mode becomes explosive (pure imaginary frequency) with typical growing rate of a few</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhyS...91j5602G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhyS...91j5602G"><span id="translatedtitle">Collapse of nonlinear <span class="hlt">electron</span> <span class="hlt">plasma</span> waves in a <span class="hlt">plasma</span> layer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grimalsky, V.; Koshevaya, S.; Rapoport, Yu; Kotsarenko, A.</p> <p>2016-10-01</p> <p>The excitation of nonlinear <span class="hlt">electron</span> <span class="hlt">plasma</span> waves in the <span class="hlt">plasma</span> layer is investigated theoretically. This excitation is realized by means of initial oscillatory perturbations of the volume <span class="hlt">electron</span> concentration or by initial oscillatory distributions of the longitudinal <span class="hlt">electron</span> velocity. The amplitudes of the initial perturbations are small and the manifestation of the volume nonlinearity is absent. When the amplitudes of the initial perturbations exceed some thresholds, the values of the <span class="hlt">electron</span> concentration near the <span class="hlt">plasma</span> boundary increase catastrophically. The maxima of the <span class="hlt">electron</span> concentration reach extremely high magnitudes, and sharp peaks in the <span class="hlt">electron</span> concentration occur, which are localized both in the longitudinal and transverse directions. This effect is interpreted as wave collapse near the <span class="hlt">plasma</span> boundary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM13D2545B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM13D2545B"><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.</p> <p>2015-12-01</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; this beam, 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" (THEMIS) observations.</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://www.osti.gov/scitech/servlets/purl/603710','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/603710"><span id="translatedtitle"><span class="hlt">Plasma</span> lenses for focusing relativistic <span class="hlt">electron</span> beams</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Govil, R.; Wheeler, S.; Leemans, W.</p> <p>1997-04-01</p> <p>The next generation of colliders require tightly focused beams with high luminosity. To focus charged particle beams for such applications, a <span class="hlt">plasma</span> focusing scheme has been proposed. <span class="hlt">Plasma</span> lenses can be overdense (<span class="hlt">plasma</span> density, n{sub p} much greater than <span class="hlt">electron</span> beam density, n{sub b}) or underdense (n{sub p} less than 2 n{sub b}). In overdense lenses the space-charge force of the <span class="hlt">electron</span> beam is canceled by the <span class="hlt">plasma</span> and the remaining magnetic force causes the <span class="hlt">electron</span> beam to self-pinch. The focusing gradient is nonlinear, resulting in spherical aberrations. In underdense lenses, the self-forces of the <span class="hlt">electron</span> beam cancel, allowing the <span class="hlt">plasma</span> ions to focus the beam. Although for a given beam density, a uniform underdense lens produces smaller focusing gradients than an overdense lens, it produces better beam quality since the focusing is done by <span class="hlt">plasma</span> ions. The underdense lens can be improved by tapering the density of the <span class="hlt">plasma</span> for optimal focusing. The underdense lens performance can be enhanced further by producing adiabatic <span class="hlt">plasma</span> lenses to avoid the Oide limit on spot size due to synchrotron radiation by the <span class="hlt">electron</span> beam. The <span class="hlt">plasma</span> lens experiment at the Beam Test Facility (BTF) is designed to study the properties of <span class="hlt">plasma</span> lenses in both overdense and underdense regimes. In particular, important issues such as <span class="hlt">electron</span> beam matching, time response of the lens, lens aberrations and shot-to-shot reproducibility are being investigated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19860049558&hterms=Earth+Layer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DEarth%2BLayer','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19860049558&hterms=Earth+Layer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DEarth%2BLayer"><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://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://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> <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://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://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016AIPA....6g5313W&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016AIPA....6g5313W&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Electron</span> density and <span class="hlt">plasma</span> dynamics of a colliding <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>Wiechula, J.; Schönlein, A.; Iberler, M.; Hock, C.; Manegold, T.; Bohlender, B.; Jacoby, J.</p> <p>2016-07-01</p> <p>We present experimental results of two head-on colliding <span class="hlt">plasma</span> sheaths accelerated by pulsed-power-driven coaxial <span class="hlt">plasma</span> accelerators. The measurements have been performed in a small vacuum chamber with a neutral-gas prefill of ArH2 at gas pressures between 17 Pa and 400 Pa and load voltages between 4 kV and 9 kV. As the <span class="hlt">plasma</span> sheaths collide, the <span class="hlt">electron</span> density is significantly increased. The <span class="hlt">electron</span> density reaches maximum values of ≈8 ṡ 1015 cm-3 for a single accelerated <span class="hlt">plasma</span> and a maximum value of ≈2.6 ṡ 1016 cm-3 for the <span class="hlt">plasma</span> collision. Overall a raise of the <span class="hlt">plasma</span> density by a factor of 1.3 to 3.8 has been achieved. A scaling behavior has been derived from the values of the <span class="hlt">electron</span> density which shows a disproportionately high increase of the <span class="hlt">electron</span> density of the collisional case for higher applied voltages in comparison to a single accelerated <span class="hlt">plasma</span>. Sequences of the <span class="hlt">plasma</span> collision have been taken, using a fast framing camera to study the <span class="hlt">plasma</span> dynamics. These sequences indicate a maximum collision velocity of 34 km/s.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950045562&hterms=plasma+field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dplasma%2Bfield','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950045562&hterms=plasma+field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dplasma%2Bfield"><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/2012AnGeo..30..467L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AnGeo..30..467L"><span id="translatedtitle">Electromagnetic ELF wave intensification associated with fast earthward flows in mid-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>Liang, J.; Ni, B.; Cully, C. M.; Donovan, E. F.; Thorne, R. M.; Angelopoulos, V.</p> <p>2012-03-01</p> <p>In this study we perform a statistical survey of the extremely-low-frequency wave activities associated with fast earthward flows in the mid-tail central <span class="hlt">plasma</span> <span class="hlt">sheet</span> (CPS) based upon THEMIS measurements. We reveal clear trends of increasing wave intensity with flow enhancement over a broad frequency range, from below fLH (lower-hybrid resonant frequency) to above fce (<span class="hlt">electron</span> gyrofrequency). We mainly investigate two electromagnetic wave modes, the lower-hybrid waves at frequencies below fLH, and the whistler-mode waves in the frequency range fLH < f < fce. The waves at f < fLH dramatically intensify during fast flow intervals, and tend to contain strong electromagnetic components in the high-<span class="hlt">plasma</span>-beta CPS region, consistent with the theoretical expectation of the lower-hybrid drift instability in the center region of the tail current <span class="hlt">sheet</span>. ULF waves with very large perpendicular wavenumber might be Doppler-shifted by the flows and also partly contribute to the observed waves in the lower-hybrid frequency range. The fast flow activity substantially increases the occurrence rate and peak magnitude of the electromagnetic waves in the frequency range fLH < f < fce, though they still tend to be short-lived and sporadic in occurrence. We also find that the <span class="hlt">electron</span> pitch-angle distribution in the mid-tail CPS undergoes a variation from negative anisotropy (perpendicular temperature smaller than parallel temperature) during weak flow intervals, to more or less positive anisotropy (perpendicular temperature larger than parallel temperature) during fast flow intervals. The flow-related electromagnetic whistler-mode wave tends to occur in conjunction with positive <span class="hlt">electron</span> anisotropy.</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://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>Sevinçli, Hâldun; Sevik, Cem</p> <p>2014-12-01</p> <p><span class="hlt">Electron</span>, phonon, and thermoelectric transport properties of α-, β-, γ-, and 6,6,12-graphyne <span class="hlt">sheets</span> are compared and contrasted with those of graphene. α-, β-, and 6,6,12-graphynes, with direction dependent Dirac dispersions, have higher <span class="hlt">electronic</span> transmittance than graphene. γ-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. γ-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://adsabs.harvard.edu/abs/2011AGUFMSM51B2068W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMSM51B2068W"><span id="translatedtitle">Dawn-dusk asymmetries in <span class="hlt">plasma</span> <span class="hlt">sheet</span> particle distributions and the average behaviour of magnetotail current systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Walsh, A. P.; Forsyth, C.; Owen, C. J.; Fazakerley, A. N.; Dandouras, I. S.</p> <p>2011-12-01</p> <p>We present the results of a survey of Cluster PEACE and CIS-CODIF data taken in the 2001-2006 tail seasons, building on the work of Walsh et al. (GRL, 2011). We examine the average pitch angle distributions of protons and <span class="hlt">electrons</span> in the magnetotail as a function of proton <span class="hlt">plasma</span> beta, restricted to times when the magnetosphere was exposed to steady (on a 3 hour timescale) IMF conditions and focussing in particular on dawn-dusk asymmetries. We confirm that, on average, the 2 component proton <span class="hlt">plasma</span> <span class="hlt">sheet</span> exists duskward of the noon-midnight meridian under steady northward IMF. An associated population of cold <span class="hlt">electrons</span> is also observed. Dawnward of the noon-midnight meridian there are no significant fluxes of the cold component of protons and much reduced fluxes of the cold <span class="hlt">electron</span> component, implying transport across the dusk magnetopause is the dominant formation mechanism of the two component <span class="hlt">plasma</span> <span class="hlt">sheet</span> for both protons and <span class="hlt">electrons</span>. Under southward IMF, dawn-dusk asymmetries in the protons are controlled by the Y component of the IMF. For the <span class="hlt">electrons</span> higher fluxes of high energy, field-aligned, particles are observed at dusk than at dawn. This suggests a link to a duskward offset of the tail neutral line and the preferential observation of substorm-related tail signatures in the premidnight sector. We also consider the relationship between the observed particle populations and the average behaviour of the large-scale magnetotail current systems as revealed by the Curlometer.</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%3D80%26Ntt%3D%2528Planck%252C%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%3D80%26Ntt%3D%2528Planck%252C%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://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/449481','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/449481"><span id="translatedtitle">Radial evolution of the finite-width <span class="hlt">plasma</span> <span class="hlt">sheet</span> in a z-pinch: A parametric analysis based on conservation laws</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sherar, A.G.</p> <p>1996-12-31</p> <p>A simple method that allows to estimate the macroscopic variables (width, temperature, density, radial velocity, etc.) of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> in the first compression of a z-pinch, is presented. Following the snow-plow model, the radial compression is assumed as a process in which the mass is swept by a <span class="hlt">sheet</span> of finite width. Very high pressures can be reached inside the <span class="hlt">sheet</span> due to magnetic compression, higher than the filling gas pressure. A quasi-equilibrium hypothesis for the pressure of the layer is defined. From this assumption the thickness of the dense <span class="hlt">plasma</span> <span class="hlt">sheet</span> can be estimated. A set of MHD equations that include a term to compute total energy losses is used. The system of equations is written in the interface reference system in which the internal boundary of the <span class="hlt">sheet</span> is at rest. In this early stage of the compression, the <span class="hlt">plasma</span> temperature is mainly due to heavy particles. The results obtained using this model can explain ionic temperatures measured in cold <span class="hlt">plasmas</span> which cannot be explained from <span class="hlt">electron</span>-ion collisions. From an analytical study of the formation solution, a well-defined range of validity for each parameter of the model has been found. Based on physical conditions, these ranges of validity give a criterion to understanding the necessary conditions to build and maintain a moving <span class="hlt">plasma</span> <span class="hlt">sheet</span>. Using this model, other geometries besides the cylindrical one can be analyzed in the future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5152996','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5152996"><span id="translatedtitle">Model of <span class="hlt">electron</span> collecting <span class="hlt">plasma</span> contactors</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Davis, V.A.; Katz, I.; Mandell, M.J.; Parks, D.E. )</p> <p>1991-06-01</p> <p>In laboratory experiments, <span class="hlt">plasma</span> contactors are observed to collect ampere-level <span class="hlt">electron</span> currents with low impedance. In order to extend the laboratory experience to the low-earth-orbit environment, a model of <span class="hlt">plasma</span> contactors is being developed. Laboratory results are being used to support and validate the model development. The important physical processes observed in the laboratory are that the source <span class="hlt">plasma</span> is separated from the background <span class="hlt">plasma</span> by a double layer and that ionization of the expellant gas by the collected <span class="hlt">electrons</span> creates the bulk of the ions that leave the source <span class="hlt">plasma</span>. The model, which uses Poisson's equation with a physical charge density that includes the ion and <span class="hlt">electron</span> components of both the source and the ambient <span class="hlt">plasmas</span>, reproduces this phenomenon for typical experimental parameters. The calculations, in agreement with the laboratory results, show little convergence of the accelerated <span class="hlt">electrons</span>. The angular momentum of the incoming <span class="hlt">electrons</span> dramatically reduces the peak <span class="hlt">electron</span> density. These <span class="hlt">electrons</span> ionize enough gas to generate the source <span class="hlt">plasma</span>. Calculations show that the increase in ionization rate with potential produces a steep rise in collected current with increasing potential as seen in the laboratory. 26 refs.</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://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://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://ntrs.nasa.gov/search.jsp?R=19910048734&hterms=flow+tube&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dflow%2Btube','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910048734&hterms=flow+tube&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dflow%2Btube"><span id="translatedtitle">Average patterns of precipitation and <span class="hlt">plasma</span> flow in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> flux tubes during steady magnetospheric convection</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sergeev, V. A.; Lennartsson, W.; Pellinen, R.; Vallinkoski, M.; Fedorova, N. I.</p> <p>1990-01-01</p> <p>Average patterns of <span class="hlt">plasma</span> drifts and auroral precipitation in the nightside auroral zone were constructed during a steady magnetospheric convection (SMC) event on February 19, 1978. By comparing these patterns with the measurements in the midtail <span class="hlt">plasma</span> <span class="hlt">sheet</span> made by ISEE-1, and using the corresponding magnetic field model, the following features are inferred: (1) the concentration of the earthward convection in the midnight portion of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> (convection jet); (2) the depleted <span class="hlt">plasma</span> energy content of the flux tubes in the convection jet region; and (3) the Region-1 field-aligned currents generated in the midtail <span class="hlt">plasma</span> <span class="hlt">sheet</span>. It is argued that these three elements are mutually consistent features appearing in the process of ionosphere-magnetosphere interaction during SMC periods. These configurational characteristics resemble the corresponding features of substorm expansions (enhanced convection and 'dipolarized' magnetic field within the substorm current wedge) and appear to play the same role in regulating the <span class="hlt">plasma</span> flow in the flux tubes connected to 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/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/2008AGUSMSM43C..02S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUSMSM43C..02S"><span id="translatedtitle">Study of the turbulence in the central <span class="hlt">plasma</span> <span class="hlt">sheet</span> using the CLUSTER satellite data</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.; Arancibia Riveros, K.; Bosqued, J.; Antonova, E.</p> <p>2008-05-01</p> <p>Recent studies are shown that the turbulent processes in the space <span class="hlt">plasmas</span> are very important. It includes the behavior of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> <span class="hlt">plasma</span> during geomagnetic substorms and storms. Study of the <span class="hlt">plasma</span> turbulence in the central <span class="hlt">plasma</span> <span class="hlt">sheet</span> was made using the CLUSTER satellite mission data. For this studies we used the Cluster Ion Spectrometry experiment (CIS), and fluxgate magnetometer (FGM) data for studying fluctuations of the <span class="hlt">plasma</span> bulk velocity and geomagnetic field fluctuations for different levels of geomagnetic activity and different locations inside the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. Case studies for the orbits during quiet geomagnetic conditions, different phases of geomagnetic substroms and storms showed that the properties of <span class="hlt">plasma</span> turbulence inside the <span class="hlt">sheet</span> differ significantly for all afore mentioned cases. Variations in the probability distribution functions, flatness factors, local intermittency measure parameters, and eddy diffusion coefficients indicate that the turbulence increases significantly during substorm growth and expansion phases and decreases slowly to the initial level during the recovery phase. It became even stronger during the storm main phase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011APS..GECAM1002G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011APS..GECAM1002G"><span id="translatedtitle"><span class="hlt">Electron</span> Temperature Modification in Gas Discharge <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>Godyak, Valery</p> <p>2011-10-01</p> <p>In gas discharge <span class="hlt">plasma</span> with a Maxwellian <span class="hlt">electron</span> energy distribution function (EEDF), the ionization balance results in the <span class="hlt">electron</span> temperature Te being solely a function of the product of gas pressure p and <span class="hlt">plasma</span> characteristic size d, Te = Te(pd), independently on <span class="hlt">plasma</span> density and <span class="hlt">electron</span> heating mechanism. This common feature of gas discharge <span class="hlt">plasma</span> takes place in self-sustained discharges where ionization is locally coupled with <span class="hlt">electron</span> heating, usually in a uniform heating electric field. At such condition, there is no room for <span class="hlt">electron</span> temperature change at fixed pd. Variety of non-equilibrium phenomena observed in self-organized dc and rf discharge structures, and in relaxation process therein suggests the way to EEDF and Te modification. At such conditions, the <span class="hlt">electron</span> heating can be separated (in space or/and in time) from the ionization. Few examples of such discharge structures in well know stationary dc and rf discharges and in <span class="hlt">plasma</span> transient processes, leading to considerable mean <span class="hlt">electron</span> energy reduction, will be considered in the presentation together with abbreviated review of existing methods and experimental results on EEDF control in laboratory <span class="hlt">plasmas</span>. This work was supported in part by the DOE OFES (Contract No DE-SC0001939).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21443325','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21443325"><span id="translatedtitle">Emission current formation in <span class="hlt">plasma</span> <span class="hlt">electron</span> emitters</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gruzdev, V. A.; Zalesski, V. G.</p> <p>2010-12-15</p> <p>A model of the <span class="hlt">plasma</span> <span class="hlt">electron</span> emitter is considered, in which the current redistribution over electrodes of the emitter gas-discharge structure and weak electric field formation in <span class="hlt">plasma</span> are taken into account as functions of the emission current. The calculated and experimental dependences of the switching parameters, extraction efficiency, and strength of the electric field in <span class="hlt">plasma</span> on the accelerating voltage and geometrical sizes of the emission channel are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NIMPA.829..254A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NIMPA.829..254A"><span id="translatedtitle"><span class="hlt">Plasma</span> production for <span class="hlt">electron</span> acceleration by resonant <span class="hlt">plasma</span> wave</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Anania, M. P.; Biagioni, A.; Chiadroni, E.; Cianchi, A.; Croia, M.; Curcio, A.; Di Giovenale, D.; Di Pirro, G. P.; Filippi, F.; Ghigo, A.; Lollo, V.; Pella, S.; Pompili, R.; Romeo, S.; Ferrario, M.</p> <p>2016-09-01</p> <p><span class="hlt">Plasma</span> wakefield acceleration is the most promising acceleration technique known nowadays, able to provide very high accelerating fields (10-100 GV/m), enabling acceleration of <span class="hlt">electrons</span> to GeV energy in few centimeter. However, the quality of the <span class="hlt">electron</span> bunches accelerated with this technique is still not comparable with that of conventional accelerators (large energy spread, low repetition rate, and large emittance); radiofrequency-based accelerators, in fact, are limited in accelerating field (10-100 MV/m) requiring therefore hundred of meters of distances to reach the GeV energies, but can provide very bright <span class="hlt">electron</span> bunches. To combine high brightness <span class="hlt">electron</span> bunches from conventional accelerators and high accelerating fields reachable with <span class="hlt">plasmas</span> could be a good compromise allowing to further accelerate high brightness <span class="hlt">electron</span> bunches coming from LINAC while preserving <span class="hlt">electron</span> beam quality. Following the idea of <span class="hlt">plasma</span> wave resonant excitation driven by a train of short bunches, we have started to study the requirements in terms of <span class="hlt">plasma</span> for SPARC_LAB (Ferrario et al., 2013 [1]). In particular here we focus on hydrogen <span class="hlt">plasma</span> discharge, and in particular on the theoretical and numerical estimates of the ionization process which are very useful to design the discharge circuit and to evaluate the current needed to be supplied to the gas in order to have full ionization. Eventually, the current supplied to the gas simulated will be compared to that measured experimentally.</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://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 PAGES</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://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/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 E×B 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/cgi-bin/nph-data_query?bibcode=2016PSST...25d7001R&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016PSST...25d7001R&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Electron</span> density measurements in highly electronegative <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>Rafalskyi, D.; Lafleur, T.; Aanesland, A.</p> <p>2016-08-01</p> <p>In this paper we present experimental measurements of the <span class="hlt">electron</span> density in very electronegative ‘ion–ion’ Ar–SF6 <span class="hlt">plasmas</span> where previous investigations using Langmuir probes have observed electronegativities of up to 5000. The <span class="hlt">electron</span> density is measured using a short matched dipole probe technique that provides a tolerance better than  ±2 · 1013 m‑3. The results demonstrate that the <span class="hlt">electron</span> density in the low pressure <span class="hlt">plasma</span> source (which contains a magnetic filter) can be reduced to around 2.7 · 1013 m‑3 with a corresponding <span class="hlt">plasma</span> electronegativity of about 4000; close to that from fluid simulation predictions. The highest electronegativity, and lowest <span class="hlt">electron</span> density, is achieved with a pure SF6 <span class="hlt">plasma</span>, while adding only 6% SF6 to Ar allows the electronegativity to be increased from 0 to a few hundred with a corresponding decrease in the <span class="hlt">electron</span> density by more than a thousand. The impedance probe based on a short matched dipole appears to be a practical diagnostic that can be used for independent measurements of the <span class="hlt">electron</span> density in very electronegative <span class="hlt">plasmas</span>, and opens up the possibility to further investigate and optimize electronegative <span class="hlt">plasma</span> sources.</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/2016PSST...25d7001R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PSST...25d7001R"><span id="translatedtitle"><span class="hlt">Electron</span> density measurements in highly electronegative <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>Rafalskyi, D.; Lafleur, T.; Aanesland, A.</p> <p>2016-08-01</p> <p>In this paper we present experimental measurements of the <span class="hlt">electron</span> density in very electronegative ‘ion-ion’ Ar-SF6 <span class="hlt">plasmas</span> where previous investigations using Langmuir probes have observed electronegativities of up to 5000. The <span class="hlt">electron</span> density is measured using a short matched dipole probe technique that provides a tolerance better than  ±2 · 1013 m-3. The results demonstrate that the <span class="hlt">electron</span> density in the low pressure <span class="hlt">plasma</span> source (which contains a magnetic filter) can be reduced to around 2.7 · 1013 m-3 with a corresponding <span class="hlt">plasma</span> electronegativity of about 4000; close to that from fluid simulation predictions. The highest electronegativity, and lowest <span class="hlt">electron</span> density, is achieved with a pure SF6 <span class="hlt">plasma</span>, while adding only 6% SF6 to Ar allows the electronegativity to be increased from 0 to a few hundred with a corresponding decrease in the <span class="hlt">electron</span> density by more than a thousand. The impedance probe based on a short matched dipole appears to be a practical diagnostic that can be used for independent measurements of the <span class="hlt">electron</span> density in very electronegative <span class="hlt">plasmas</span>, and opens up the possibility to further investigate and optimize electronegative <span class="hlt">plasma</span> sources.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PSST...23c5010L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PSST...23c5010L"><span id="translatedtitle"><span class="hlt">Electron</span> heating in capacitively coupled <span class="hlt">plasmas</span> revisited</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lafleur, T.; Chabert, P.; Booth, J. P.</p> <p>2014-06-01</p> <p>We revisit the problem of <span class="hlt">electron</span> heating in capacitively coupled <span class="hlt">plasmas</span> (CCPs), and propose a method for quantifying the level of collisionless and collisional heating in <span class="hlt">plasma</span> simulations. The proposed procedure, based on the <span class="hlt">electron</span> mechanical energy conservation equation, is demonstrated with particle-in-cell simulations of a number of single and multi-frequency CCPs operated in regimes of research and industrial interest. In almost all cases tested, the total <span class="hlt">electron</span> heating is comprised of collisional (ohmic) and pressure heating parts. This latter collisionless component is in qualitative agreement with the mechanism of <span class="hlt">electron</span> heating predicted from the recent re-evaluation of theoretical models. Finally, in very electrically asymmetric <span class="hlt">plasmas</span> produced in multi-frequency discharges, we observe an additional collisionless heating mechanism associated with <span class="hlt">electron</span> inertia.</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/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/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</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 Alfvén 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 Δ' 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://adsabs.harvard.edu/abs/2001APS..GECRF1005L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001APS..GECRF1005L"><span id="translatedtitle"><span class="hlt">Electron</span> Beam Diagnostics in <span class="hlt">Plasmas</span> Based on <span class="hlt">Electron</span> Beam Ionization</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leonhardt, Darrin; Leal-Quiros, Edbertho; Blackwell, David; Walton, Scott; Murphy, Donald; Fernsler, Richard; Meger, Robert</p> <p>2001-10-01</p> <p>Over the last few years, <span class="hlt">electron</span> beam ionization has been shown to be a viable generator of high density <span class="hlt">plasmas</span> with numerous applications in materials modification. To better understand these <span class="hlt">plasmas</span>, we have fielded <span class="hlt">electron</span> beam diagnostics to more clearly understand the propagation of the beam as it travels through the background gas and creates the <span class="hlt">plasma</span>. These diagnostics vary greatly in sophistication, ranging from differentially pumped systems with energy selective elements to metal 'hockey pucks' covered with thin layers of insulation to electrically isolate the detector from the <span class="hlt">plasma</span> but pass high energy beam <span class="hlt">electrons</span>. Most importantly, absolute measurements of spatially resolved beam current densities are measured in a variety of pulsed and continuous beam sources. The energy distribution of the beam current(s) will be further discussed, through experiments incorporating various energy resolving elements such as simple grids and more sophisticated cylindrical lens geometries. The results are compared with other experiments of high energy <span class="hlt">electron</span> beams through gases and appropriate disparities and caveats will be discussed. Finally, <span class="hlt">plasma</span> parameters are correlated to the measured beam parameters for a more global picture of <span class="hlt">electron</span> beam produced <span class="hlt">plasmas</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000PhLA..269..144S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000PhLA..269..144S"><span id="translatedtitle">Nonlinear magnetohydrodynamics of <span class="hlt">electron</span>-positron <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>Shukla, P. K.; Dasgupta, B.; Sakanaka, P. H.</p> <p>2000-05-01</p> <p>A set of nonlinear magnetohydrodynamic (MHD) equations for magnetized, nonrelativistic <span class="hlt">electron</span>-positron <span class="hlt">plasmas</span> is derived by employing a two fluid model that is supplemented by Ampère's and Faraday's laws. The nonlinear equations show how the baroclinic driver (the Biermann battery) generates the <span class="hlt">electron</span> positron flows and how these flows give rise to <span class="hlt">plasma</span> currents which act as a source for the magnetic fields. The newly derived nonlinear equations form a basis for investigating waves, instabilities, as well as coherent nonlinear structures, in addition to studying exact equilibria of <span class="hlt">electron</span>-positron jets in a magnetoplasma.</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-β <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-β <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-β <span class="hlt">plasma</span>.</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://adsabs.harvard.edu/abs/2010JGRA..11512224D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JGRA..11512224D"><span id="translatedtitle">Multiple harmonic ULF waves in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer: Instability analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Denton, R. E.; Engebretson, M. J.; Keiling, A.; Walsh, A. P.; Gary, S. P.; DéCréAu, P. M. E.; Cattell, C. A.; RèMe, H.</p> <p>2010-12-01</p> <p>Multiple-harmonic electromagnetic waves in the ULF band have occasionally been observed in Earth's magnetosphere, both near the magnetic equator in the outer plasmasphere and in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer (PSBL) in Earth's magnetotail. Observations by the Cluster spacecraft of multiple-harmonic electromagnetic waves with fundamental frequency near the local proton cyclotron frequency, Ωcp, were recently reported in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer by Broughton et al. (2008). A companion paper surveys the entire magnetotail passage of Cluster during 2003, and reports 35 such events, all in the PSBL, and all associated with elevated fluxes of counterstreaming ions and <span class="hlt">electrons</span>. In this study we use observed pitch angle distributions of ions and <span class="hlt">electrons</span> during a wave event observed by Cluster on 9 September 2003 to perform an instability analysis. We use a semiautomatic procedure for developing model distributions composed of bi-Maxwellian components that minimizes the difference between modeled and observed distribution functions. Analysis of wave instability using the WHAMP electromagnetic <span class="hlt">plasma</span> wave dispersion code and these model distributions reveals an instability near Ωcp and its harmonics. The observed and model ion distributions exhibit both beam-like and ring-like features which might lead to instability. Further instability analysis with simple beam-like and ring-like model distribution functions indicates that the instability is due to the ring-like feature. Our analysis indicates that this instability persists over an enormous range in the effective ion beta (based on a best fit for the observed distribution function using a single Maxwellian distribution), β', but that the character of the instability changes with β'. For β' of order unity (for instance, the observed case with β' ˜ 0.4), the instability is predominantly electromagnetic; the fluctuating magnetic field has components in both the perpendicular and parallel directions, but the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRA..119.1572L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRA..119.1572L"><span id="translatedtitle">The relationship between sawtooth events and O+ 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>Liao, J.; Cai, X.; Kistler, L. M.; Clauer, C. R.; Mouikis, C. G.; Klecker, B.; Dandouras, I.</p> <p>2014-03-01</p> <p>In order to study the relationship between sawtooth events and the composition of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, we perform a superposed epoch analysis (SEA) of the O+ concentration inside the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> during sawtooth events and substorms sorted by different geomagnetic storm phases, using Cluster/Composition Distribution Function data. The SEA shows that the O+ content increases during sawtooth growth phase, regardless of storm phase, and reaches 20% around the onset of dipolarization. For storm main phase events, the <span class="hlt">plasma</span> <span class="hlt">sheet</span> O+ concentration during sawtooth events is only slightly higher than that observed during substorm events. However, for storm recovery phase and nonstorm time events, there is significantly more O+ within the <span class="hlt">plasma</span> <span class="hlt">sheet</span> during sawtooth events than during substorm events. No difference is found in the comparison between the O+/H+ density ratio changes during the first tooth and the subsequent teeth in a series of a sawtooth interval. Hence, there is no evidence to support the hypothesis that due to the higher O+ inside the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, subsequent teeth will lead to a closer near-Earth X line and then a wider magnetic local time response. Finally, despite the association between sawtooth events and high O+/H+ ratio, there are times when the O+/H+ density ratio is high in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> but no sawtooth event is observed, and there are sawtooth events when the O+/H+ ratio is low. This indicates that enhanced O+ is neither a necessary nor a sufficient condition but is likely one of many factors that play a role in triggering sawtooth events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22288579','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22288579"><span id="translatedtitle">Highly efficient <span class="hlt">electron</span> field emission from graphene oxide <span class="hlt">sheets</span> supported by nickel nanotip arrays.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ye, Dexian; Moussa, Sherif; Ferguson, Josephus D; Baski, Alison A; El-Shall, M Samy</p> <p>2012-03-14</p> <p><span class="hlt">Electron</span> field emission is a quantum tunneling phenomenon whereby <span class="hlt">electrons</span> are emitted from a solid surface due to a strong electric field. Graphene and its derivatives are expected to be efficient field emitters due to their unique geometry and electrical properties. So far, <span class="hlt">electron</span> field emission has only been achieved from the edges of graphene and graphene oxide <span class="hlt">sheets</span>. We have supported graphene oxide <span class="hlt">sheets</span> on nickel nanotip arrays to produce a high density of sharp protrusions within the <span class="hlt">sheets</span> and then applied electric fields perpendicular to the <span class="hlt">sheets</span>. Highly efficient and stable field emission with low turn-on fields was observed for these graphene oxide <span class="hlt">sheets</span>, because the protrusions appear to locally enhance the electric field and dramatically increase field emission. Our simple and robust approach provides prospects for the development of practical <span class="hlt">electron</span> sources and advanced devices based on graphene and graphene oxide field emitters. PMID:22288579</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060009468&hterms=relative+density&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Drelative%2Bdensity','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060009468&hterms=relative+density&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Drelative%2Bdensity"><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://adsabs.harvard.edu/abs/2016SPD....4730501F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SPD....4730501F"><span id="translatedtitle">An Evaluation of Motions Found in Multiple Supra-Arcade <span class="hlt">Plasma</span> <span class="hlt">Sheets</span> with Local Correlation Tracking</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Freed, Michael; McKenzie, David Eugene</p> <p>2016-05-01</p> <p><span class="hlt">Plasma</span> <span class="hlt">sheets</span> can be seen in the corona above arcade loops that form shortly after the eruption phase of a solar flare. These structures are considered to be the location where current <span class="hlt">sheets</span> can form, which are a key component for magnetic reconnection to take place. The objective of this study is to quantify the motion seen in these <span class="hlt">plasma</span> <span class="hlt">sheets</span> and to determine how these characteristics might vary over multiple length scales. We use contrast-enhanced EUV observations of five different <span class="hlt">plasma</span> <span class="hlt">sheets</span> to construct velocity maps of <span class="hlt">plasma</span> motion — in the plane of the sky — via a Fourier local correlation tracking program. These derived velocities were then used to calculate angle-integrated power spectral density of intensity, kinetic energy, and enstrophy to determine if any self-similarity exists. The derived velocity fields also allowed for measurements of the kinetic energy density, enstrophy density, and magnetic diffusivity. We will also present the first reported observational evidence of Kelvin-Helmholtz instabilities forming at the interface of supra-arcade downflows (SADs) and the surrounding supra-arcade <span class="hlt">plasma</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20782390','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20782390"><span id="translatedtitle">Runaway <span class="hlt">electron</span> generation in a cooling <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Smith, H.; Helander, P.; Eriksson, L.-G.; Fueloep, T.</p> <p>2005-12-15</p> <p>The usual calculation of Dreicer [Phys. Rev. 115, 238 (1959); 117, 329 (1960)] generation of runaway <span class="hlt">electrons</span> assumes that the <span class="hlt">plasma</span> is in a steady state. In a tokamak disruption this is not necessarily true since the <span class="hlt">plasma</span> cools down quickly and the collision time for <span class="hlt">electrons</span> at the runaway threshold energy can be comparable to the cooling time. The <span class="hlt">electron</span> distribution function then acquires a high-energy tail which can easily be converted to a burst of runaways by the rising electric field. This process is investigated and simple criteria for its importance are derived. If no rapid losses of fast <span class="hlt">electrons</span> occur, this can be a more important source of runaway <span class="hlt">electrons</span> than ordinary Dreicer generation in tokamak disruptions.</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://www.osti.gov/scitech/biblio/6118876','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6118876"><span id="translatedtitle"><span class="hlt">Electron</span> transport in one-dimensional <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wienke, B.R.</p> <p>1983-11-01</p> <p>A one-dimensional, multigroup, discrete ordinates technique for computing <span class="hlt">electron</span> energy deposition in <span class="hlt">plasmas</span> is detailed. The Fokker-Planck collision operator is employed in the continuous approximation and electric fields (considered external) are included in the equation. Bremsstrahlung processes are not treated. Comparisons with analytic and Monte Carlo results are given. Fits to deposition profiles and energy scaling are proposed and discussed for monoenergetic and Maxwellian sources in the range, 0 to 150 keV, with and without uniform fields. The techniques employed to track <span class="hlt">electrons</span> are generally useful in situations where the background <span class="hlt">plasma</span> temperature is an order of magnitude smaller than the <span class="hlt">electron</span> energy and collective <span class="hlt">plasma</span> effects are negligible. We have used the approach successfully in laser pellet implosion applications.</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://www.osti.gov/scitech/biblio/22038500','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22038500"><span id="translatedtitle"><span class="hlt">Electron</span> cyclotron emission imaging in tokamak <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Munsat, Tobin; Domier, Calvin W.; Kong, Xiangyu; Liang, Tianran; Luhmann, Jr.; Neville C.; Tobias, Benjamin J.; Lee, Woochang; Park, Hyeon K.; Yun, Gunsu; Classen, Ivo. G. J.; Donne, Anthony J. H.</p> <p>2010-07-01</p> <p>We discuss the recent history and latest developments of the <span class="hlt">electron</span> cyclotron emission imaging diagnostic technique, wherein <span class="hlt">electron</span> temperature is measured in magnetically confined <span class="hlt">plasmas</span> with two-dimensional spatial resolution. The key enabling technologies for this technique are the large-aperture optical systems and the linear detector arrays sensitive to millimeter-wavelength radiation. We present the status and recent progress on existing instruments as well as new systems under development for future experiments. We also discuss data analysis techniques relevant to <span class="hlt">plasma</span> imaging diagnostics and present recent temperature fluctuation results from the tokamak experiment for technology oriented research (TEXTOR).</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://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/1999AIPC..498..435P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999AIPC..498..435P"><span id="translatedtitle">Confinement of pure ion <span class="hlt">plasma</span> in a cylindrical 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>Paul, Stephen F.; Chao, Edward H.; Davidson, Ronald C.; Phillips, Cynthia K.</p> <p>1999-12-01</p> <p>A novel method for containing a pure ion <span class="hlt">plasma</span> at thermonuclear densities and temperatures has been modeled. The method combines the confinement principles of a Penning-Malmberg trap and a pulsed theta-pinch. A conventional Penning trap can confine a uniform-density <span class="hlt">plasma</span> of about 5×1011cm-3 with a 30-Tesla magnetic field. However, if the axial field is ramped, a much higher local ion density can be obtained. Starting with a 107cm-3 trapped deuterium <span class="hlt">plasma</span> at the Brillouin limit (B=0.6 Tesla), the field is ramped to 30 Tesla. Because the <span class="hlt">plasma</span> is comprised of particles of only one sign of charge, transport losses are very low, i.e., the conductivity is high. As a result, the ramped field does not penetrate the <span class="hlt">plasma</span> and a diamagnetic surface current is generated, with the ions being accelerated to relativistic velocities. To counteract the inward j×B forces from this induced current, additional ions are injected into the <span class="hlt">plasma</span> along the axis to increase the density (and mutual electrostatic repulsion) of the target <span class="hlt">plasma</span>. In the absence of the higher magnetic field in the center, the ions drift outward until a balance is established between the outward driving forces (centrifugal, electrostatic, pressure gradient) and the inward j×B force. An equilibrium calculation using a relativistic, 1-D, cold-fluid model shows that a <span class="hlt">plasma</span> can be trapped in a hollow, 49-cm diameter, 0.2-cm thick cylinder with a density exceeding 4×1014cm-3.</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('https://www.ncbi.nlm.nih.gov/pubmed/25666919','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25666919"><span id="translatedtitle"><span class="hlt">Electronic</span> transport properties of BN <span class="hlt">sheet</span> on adsorption of ammonia (NH3) gas.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Srivastava, Anurag; Bhat, Chetan; Jain, Sumit Kumar; Mishra, Pankaj Kumar; Brajpuriya, Ranjeet</p> <p>2015-03-01</p> <p>We report the detection of ammonia gas through <span class="hlt">electronic</span> and transport properties analysis of boron nitride <span class="hlt">sheet</span>. The density functional theory (DFT) based ab initio approach has been used to calculate the <span class="hlt">electronic</span> and transport properties of BN <span class="hlt">sheet</span> in presence of ammonia gas. Analysis confirms that the band gap of the <span class="hlt">sheet</span> increases due to presence of ammonia. Out of different positions, the bridge site is the most favorable position for adsorption of ammonia and the mechanism of interaction falls between weak electrostatic interaction and chemisorption. On relaxation, change in the bond angles of the ammonia molecule in various configurations has been reported with the distance between NH3 and the <span class="hlt">sheet</span>. An increase in the transmission of <span class="hlt">electrons</span> has been observed on increasing the bias voltage and I-V relationship. This confirms that, the current increases on applying the bias when ammonia is introduced while a very small current flows for pure BN <span class="hlt">sheet</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25666919','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25666919"><span id="translatedtitle"><span class="hlt">Electronic</span> transport properties of BN <span class="hlt">sheet</span> on adsorption of ammonia (NH3) gas.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Srivastava, Anurag; Bhat, Chetan; Jain, Sumit Kumar; Mishra, Pankaj Kumar; Brajpuriya, Ranjeet</p> <p>2015-03-01</p> <p>We report the detection of ammonia gas through <span class="hlt">electronic</span> and transport properties analysis of boron nitride <span class="hlt">sheet</span>. The density functional theory (DFT) based ab initio approach has been used to calculate the <span class="hlt">electronic</span> and transport properties of BN <span class="hlt">sheet</span> in presence of ammonia gas. Analysis confirms that the band gap of the <span class="hlt">sheet</span> increases due to presence of ammonia. Out of different positions, the bridge site is the most favorable position for adsorption of ammonia and the mechanism of interaction falls between weak electrostatic interaction and chemisorption. On relaxation, change in the bond angles of the ammonia molecule in various configurations has been reported with the distance between NH3 and the <span class="hlt">sheet</span>. An increase in the transmission of <span class="hlt">electrons</span> has been observed on increasing the bias voltage and I-V relationship. This confirms that, the current increases on applying the bias when ammonia is introduced while a very small current flows for pure BN <span class="hlt">sheet</span>. PMID:25666919</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://adsabs.harvard.edu/abs/2014PhDT........18N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhDT........18N"><span id="translatedtitle"><span class="hlt">Electron</span> density measurements for <span class="hlt">plasma</span> adaptive optics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Neiswander, Brian W.</p> <p></p> <p>Over the past 40 years, there has been growing interest in both laser communications and directed energy weapons that operate from moving aircraft. As a laser beam propagates from an aircraft in flight, it passes through boundary layers, turbulence, and shear layers in the near-region of the aircraft. These fluid instabilities cause strong density gradients which adversely affect the transmission of laser energy to a target. Adaptive optics provides corrective measures for this problem but current technology cannot respond quickly enough to be useful for high speed flight conditions. This research investigated the use of <span class="hlt">plasma</span> as a medium for adaptive optics for aero-optics applications. When a laser beam passes through <span class="hlt">plasma</span>, its phase is shifted proportionally to the <span class="hlt">electron</span> density and gas heating within the <span class="hlt">plasma</span>. As a result, <span class="hlt">plasma</span> can be utilized as a dynamically controllable optical medium. Experiments were carried out using a cylindrical dielectric barrier discharge <span class="hlt">plasma</span> chamber which generated a sub-atmospheric pressure, low-temperature <span class="hlt">plasma</span>. An electrostatic model of this design was developed and revealed an important design constraint relating to the geometry of the chamber. Optical diagnostic techniques were used to characterize the <span class="hlt">plasma</span> discharge. Single-wavelength interferometric experiments were performed and demonstrated up to 1.5 microns of optical path difference (OPD) in a 633 nm laser beam. Dual-wavelength interferometry was used to obtain time-resolved profiles of the <span class="hlt">plasma</span> <span class="hlt">electron</span> density and gas heating inside the <span class="hlt">plasma</span> chamber. Furthermore, a new multi-wavelength infrared diagnostic technique was developed and proof-of-concept simulations were conducted to demonstrate the system's capabilities.</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://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 ϕ} close to the speed of light c where the vortex size δ is on the order of the magnetic Debye length λ{sub B}=|B|/4πen 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 δ ≈ λ{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://adsabs.harvard.edu/abs/2016PhPl...23h2122A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhPl...23h2122A"><span id="translatedtitle">Twisted <span class="hlt">electron</span>-acoustic waves in <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>Aman-ur-Rehman, Ali, S.; Khan, S. A.; Shahzad, K.</p> <p>2016-08-01</p> <p>In the paraxial limit, a twisted <span class="hlt">electron</span>-acoustic (EA) wave is studied in a collisionless unmagnetized <span class="hlt">plasma</span>, whose constituents are the dynamical cold <span class="hlt">electrons</span> and Boltzmannian hot <span class="hlt">electrons</span> in the background of static positive ions. The analytical and numerical solutions of the <span class="hlt">plasma</span> kinetic equation suggest that EA waves with finite amount of orbital angular momentum exhibit a twist in its behavior. The twisted wave particle resonance is also taken into consideration that has been appeared through the effective wave number qeff accounting for Laguerre-Gaussian mode profiles attributed to helical phase structures. Consequently, the dispersion relation and the damping rate of the EA waves are significantly modified with the twisted parameter η, and for η → ∞, the results coincide with the straight propagating plane EA waves. Numerically, new features of twisted EA waves are identified by considering various regimes of wavelength and the results might be useful for transport and trapping of <span class="hlt">plasma</span> particles in a two-<span class="hlt">electron</span> component <span class="hlt">plasma</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008APS..APR.K1057M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008APS..APR.K1057M&link_type=ABSTRACT"><span id="translatedtitle">Propagation of <span class="hlt">electron</span> and positron beams in long, 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>Muggli, Patric; Blue, Brent; Clayton, Chris; Decker, Franz-Joseph; Hogan, Mark; Hunag, Chengkun; Joshi, Chan; Katsouleas, Tom; Lu, Wei; Mori, Warren; O'Connell, Caollionn; Siemann, Robert; Walz, Dieter; Zhou, Miaomiao</p> <p>2008-04-01</p> <p><span class="hlt">Electron</span> beams with density larger than the <span class="hlt">plasma</span> density can propagate through <span class="hlt">plasmas</span> without significant emittance growth. The <span class="hlt">electron</span> beam expels the <span class="hlt">plasma</span> <span class="hlt">electrons</span> from the bunch volume and propagate in a pure, uniform ion column. In contrast, positron beams attract <span class="hlt">plasma</span> <span class="hlt">electrons</span> that flow through the positron bunch. As a result the <span class="hlt">plasma</span> focusing force is nonlinear, a charge halo forms around the bunch, and the bunch emittance grows. After some distance into the <span class="hlt">plasma</span>, the bunch emittance reaches an approximately constant value, and the beam and the <span class="hlt">plasma</span> focusing force reach a steady state. Experimental results obtained with <span class="hlt">electron</span> and positron bunches, as well as numerical simulation results will be presented.</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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999GeoRL..26.2137W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999GeoRL..26.2137W"><span id="translatedtitle"><span class="hlt">Plasma</span> <span class="hlt">sheet</span> dynamics in the Jovian magnetotail: Signatures For substorm-like processes ?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Woch, J.; Krupp, N.; Khurana, K. K.; Kivelson, M. G.; Roux, A.; Perraut, S.; Louarn, P.; Lagg, A.; Williams, D. J.; Livi, S.; Wilken, B.</p> <p></p> <p>During Galileo's orbit G2 in 1996 the Energetic Particles Detector (EPD) onboard the spacecraft detected a number of particle bursts with large radial/antisunward anisotropies in the distant Jovian magnetotail [Krupp et al., 1998]. In this letter we focus on a detailed analysis of one of the bursts. Prior to the onset of the burst, particle intensities at low energies increase over several hours. This phase can be interpreted as a <span class="hlt">plasma</span> loading phase. It ends after the onset of strong distortions in the magnetic field with a bipolar excursion of the north-south component being the most prominent feature. The subsequent <span class="hlt">plasma</span> <span class="hlt">sheet</span> encounters show that the <span class="hlt">plasma</span> <span class="hlt">sheet</span> has thinned considerably. Accelerated/heated ion beams first from the Jovian direction and then later from the tail direction are seen at the <span class="hlt">plasma</span> <span class="hlt">sheet</span> and lobe interfaces and intense radio and <span class="hlt">plasma</span> wave emissions are detected. The event is tentatively interpreted as a dynamical process, where the Jovian magnetotail is internally driven unstable by mass loading of magnetic flux tubes.</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/2008JGRA..113.7S33P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JGRA..113.7S33P"><span id="translatedtitle"><span class="hlt">Electron</span> density estimations derived from spacecraft potential measurements on Cluster in tenuous <span class="hlt">plasma</span> regions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pedersen, A.; Lybekk, B.; André, M.; Eriksson, A.; Masson, A.; Mozer, F. S.; Lindqvist, P.-A.; DéCréAu, P. M. E.; Dandouras, I.; Sauvaud, J.-A.; Fazakerley, A.; Taylor, M.; Paschmann, G.; Svenes, K. R.; Torkar, K.; Whipple, E.</p> <p>2008-07-01</p> <p>Spacecraft potential measurements by the EFW electric field experiment on the Cluster satellites can be used to obtain <span class="hlt">plasma</span> density estimates in regions barely accessible to other type of <span class="hlt">plasma</span> experiments. Direct calibrations of the <span class="hlt">plasma</span> density as a function of the measured potential difference between the spacecraft and the probes can be carried out in the solar wind, the magnetosheath, and the plasmashere by the use of CIS ion density and WHISPER <span class="hlt">electron</span> density measurements. The spacecraft photoelectron characteristic (photoelectrons escaping to the <span class="hlt">plasma</span> in current balance with collected ambient <span class="hlt">electrons</span>) can be calculated from knowledge of the <span class="hlt">electron</span> current to the spacecraft based on <span class="hlt">plasma</span> density and <span class="hlt">electron</span> temperature data from the above mentioned experiments and can be extended to more positive spacecraft potentials by CIS ion and the PEACE <span class="hlt">electron</span> experiments in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. This characteristic enables determination of the <span class="hlt">electron</span> density as a function of spacecraft potential over the polar caps and in the lobes of the magnetosphere, regions where other experiments on Cluster have intrinsic limitations. Data from 2001 to 2006 reveal that the photoelectron characteristics of the Cluster spacecraft as well as the electric field probes vary with the solar cycle and solar activity. The consequences for <span class="hlt">plasma</span> density measurements are addressed. Typical examples are presented to demonstrate the use of this technique in a polar cap/lobe <span class="hlt">plasma</span>.</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/2016PhPl...23h2101H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhPl...23h2101H"><span id="translatedtitle"><span class="hlt">Plasma</span> <span class="hlt">electron</span> hole kinematics. I. Momentum conservation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hutchinson, I. H.; Zhou, C.</p> <p>2016-08-01</p> <p>We analyse the kinematic properties of a <span class="hlt">plasma</span> <span class="hlt">electron</span> hole: a non-linear self-sustained localized positive electric potential perturbation, trapping <span class="hlt">electrons</span>, which behaves as a coherent entity. When a hole accelerates or grows in depth, ion and <span class="hlt">electron</span> <span class="hlt">plasma</span> momentum is changed both within the hole and outside, by an energization process we call jetting. We present a comprehensive analytic calculation of the momentum changes of an isolated general one-dimensional hole. The conservation of the total momentum gives the hole's kinematics, determining its velocity evolution. Our results explain many features of the behavior of hole speed observed in numerical simulations, including self-acceleration at formation, and hole pushing and trapping by ion streams.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3174452','PMC'); return false;" href="https://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/2016cosp...41E2152Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E2152Z"><span id="translatedtitle">Self-organization in space <span class="hlt">plasma</span>: formation of magnetic shear in 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>Zelenyi, Lev; Delcourt, Dominique; Mingalev, Oleg; Malova, Helmi; Popov, Victor; Grigorenko, Elena; Petrukovich, Anatoli</p> <p>2016-07-01</p> <p>Thin current <span class="hlt">sheets</span> are <span class="hlt">plasma</span> structures that usually appear near reconnection regions. The presence of the shear magnetic field is characteristic for these structures. Self-consistent kinetic model of magnetotail thin current <span class="hlt">sheet</span> (TCS) is used to understand the mechanisms of self-organization of sheared thin current <span class="hlt">sheets</span> in a space <span class="hlt">plasma</span>. It is shown that these configurations appear as a result of self-consistent evolution of some initial magnetic perturbation at current <span class="hlt">sheet</span> center. Two general shapes of shear TCS components are found as a function of the transverse coordinate: symmetric and antisymmetric. We show that TCS formation goes together with the emergence of field-aligned currents in the center of the current <span class="hlt">sheet</span>, as a result of north-south asymmetry of quasi-adiabatic ion motions. Ion drift currents can also contribute to the magnetic shear evolution, but their role is much less significant, their contribution depending upon the normal component Bz and the amplitude of the initial perturbation in TCS. Parametric maps illustrating different types of TCS equilibria are presented.</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> </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://ntrs.nasa.gov/search.jsp?R=19930034859&hterms=relative+density&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Drelative%2Bdensity','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930034859&hterms=relative+density&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Drelative%2Bdensity"><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>1992-01-01</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 on 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/1989JGR....94.6481C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1989JGR....94.6481C"><span id="translatedtitle"><span class="hlt">Plasma</span> and energetic <span class="hlt">electron</span> flux variations in the Mercury 1 C event - Evidence for a magnetospheric 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>Christon, S. P.</p> <p>1989-06-01</p> <p>Charge-particle and magnetic-field data obtained during the first encounter (on March 29, 1974) of Mariner 10 with the planet Mercury are reexamined, and a new interpretation of the Mariner 10 energetic <span class="hlt">electron</span>, <span class="hlt">plasma</span> <span class="hlt">electron</span>, and magnetic field data near the outbound magnetopause at Mercury is presented. It is shown that Mariner 10 sampled the hot substorm energized magnetospheric <span class="hlt">plasma</span> <span class="hlt">sheet</span> for the first 36 sec of the C event and, for the next 48 sec, alternatiely sampled hot (<span class="hlt">plasma</span> <span class="hlt">sheet</span>) and cold (boundary-layer magnetosheathlike) <span class="hlt">plasma</span> regions. It is argued that the counting rate of the ID1 event (i.e., a particle event triggering detector D1 but not the D2, D3, or D7 detectors) thoughout the C event most probably represents a pulse pileup response to about 35-175 keV <span class="hlt">electrons</span>, rather than the nominal above-175 keV <span class="hlt">electrons</span> presumed in the earlier interpretations.</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://ntrs.nasa.gov/search.jsp?R=19870050066&hterms=beam+diagnostics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dbeam%2Bdiagnostics','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870050066&hterms=beam+diagnostics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dbeam%2Bdiagnostics"><span id="translatedtitle">Velocity distributions of 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://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Eastman, T. E.; Decoster, R. J.; Frank, L. A.</p> <p>1986-01-01</p> <p>The value of measured ion-beam velocity distributions as diagnostic tools to characterize the propagation and acceleration of particle beams in the <span class="hlt">plasma-sheet</span> boundary layer is assessed. Models based on adiabatic deformation of a flowing Maxwellian, acceleration by field-aligned potentials, and current-<span class="hlt">sheet</span> acceleration are fitted to observational data, and the results are presented in extensive diagrams and graphs. The data are found to be consistent with models involving field-aligned or cross-tail potential drops, but not with models based solely on the adiabatic deformation of initially isotropic distributions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22489953','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22489953"><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://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhang, Rong; Cheng, Li-Hong; Xue, Ju-Kui</p> <p>2015-12-15</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://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</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 fermion-Dirac 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://adsabs.harvard.edu/abs/2008cosp...37.1044G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008cosp...37.1044G"><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://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goldstein, Mevlyn; Parks, George; Decreau, Pierrette; Gurgiolo, C.; Fazakerley, Andrew N.</p> <p></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 Alfvén speed, the Taylor frozen-in-flow approximation cannot be used. Consequently, this e 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://ntrs.nasa.gov/search.jsp?R=20080037619&hterms=fgm&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dfgm','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20080037619&hterms=fgm&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dfgm"><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://ntrs.nasa.gov/search.jsp?R=19770028218&hterms=ohms+law&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dohms%2Blaw','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19770028218&hterms=ohms+law&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dohms%2Blaw"><span id="translatedtitle">High conductivity magnetic tearing instability. [of neutral <span class="hlt">plasma</span> <span class="hlt">sheets</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cross, M. A.; Van Hoven, G.</p> <p>1976-01-01</p> <p>Linearized equations of magnetohydrodynamics are used to investigate the tearing mode, for arbitrary values of the conductivity, through a consideration of the additional effect of the <span class="hlt">electron</span>-inertia contribution to Ohm's law. A description is provided of the equilibrium and subsequent instability in the magnetohydrodynamic approximation. A method for solving the perturbation equations in the linear approximation is discussed and attention is given to the results in the high conductivity limit.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSM13F4226E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSM13F4226E"><span id="translatedtitle">Understanding Turbulence in the <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> and Its Role in Transport</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>El-Alaoui, M.; Ashour-Abdalla, M.; Lapenta, G.; Richard, R. L.</p> <p>2014-12-01</p> <p>In this study the nature and implications of turbulence in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> is explored with emphasis on large scale and meso-scale processes. The relationship between turbulence and reconnection, and its contribution to magnetospheric transport and dynamics will be evaluated. Observational studies to date have shown that the magnetotail rarely exhibits simple steady convection; instead, flows in the magnetotail have a high level of fluctuations. Flows driven on the scale of the entire system are well described by MHD and break up into structures that cascade to smaller scales. MHD simulation studies have shown the presence of realistic fluctuation spectra both in case studies where direct comparisons to observations have been made and in idealized test cases which have been compared to the statistical studies of observed events. The simulations do a good job of representing the effects of dissipation and yield dissipative scale lengths that are comparable to those inferred from observations. At intermediate, meso-scales, which receive energy from both large and small scales, turbulent processes are important in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, in particular around dipolarization fronts. We will explore the interaction between large-scale and smaller-scale fluctuations and their contributions to the magnetotail current <span class="hlt">sheet</span> structure. We will use a global MHD simulation and a two dimensional version of the iPIC3Dimplicit particle in cell simulation separately to examine how turbulence is related to global and local processes involved in the current <span class="hlt">sheet</span>.</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://adsabs.harvard.edu/abs/2016EP%26S...68...69N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EP%26S...68...69N"><span id="translatedtitle">Cluster observation of magnetohydrodynamic turbulence 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>Narita, Y.</p> <p>2016-04-01</p> <p>Measurement of turbulent magnetic field is presented from the Earth magnetotail crossing of the Cluster spacecraft on August 25, 2006, as an ideal case study of magnetohydrodynamic turbulence in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer on a spatial scale of about 10,000 km. The fluctuation energy of the magnetic field is evaluated in both the frequency and wavevector domains. The observed <span class="hlt">plasma</span> <span class="hlt">sheet</span> turbulence event shows anisotropy in the wavevector domain with a spectral extension perpendicular to the mean magnetic field. The analyses of the dispersion relation and phase speed diagrams indicate that the coherent wave components should be regarded as a set of the linear-mode waves and the other fluctuation components in magnetohydrodynamics. Although the magnetic field fluctuation amplitudes are sufficiently small compared to the large-scale field strength, there is no clear indication of the linear-mode dominance in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. As a lesson, magnetohydrodynamic turbulence must be modeled by including both linear-mode waves and nonlinear wave components such as sideband waves.</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/2016PlPhR..42..388M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PlPhR..42..388M"><span id="translatedtitle">Formation and evolution of flapping and ballooning waves in magnetospheric <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>Ma, J. Z. G.; Hirose, A.</p> <p>2016-05-01</p> <p>By adopting Lembége & Pellat's 2D <span class="hlt">plasma-sheet</span> model, we investigate the flankward flapping motion and Sunward ballooning propagation driven by an external source (e.g., magnetic reconnection) produced initially at the <span class="hlt">sheet</span> center. Within the ideal MHD framework, we adopt the WKB approximation to obtain the Taylor-Goldstein equation of magnetic perturbations. Fourier spectral method and Runge-Kutta method are employed in numerical simulations, respectively, under the flapping and ballooning conditions. Studies expose that the magnetic shears in the <span class="hlt">sheet</span> are responsible for the flapping waves, while the magnetic curvature and the <span class="hlt">plasma</span> gradient are responsible for the ballooning waves. In addition, the flapping motion has three phases in its temporal development: fast damping phase, slow recovery phase, and quasi-stabilized phase; it is also characterized by two patterns in space: propagating wave pattern and standing wave pattern. Moreover, the ballooning modes are gradually damped toward the Earth, with a wavelength in a scale size of magnetic curvature or <span class="hlt">plasma</span> inhomogeneity, only 1-7% of the flapping one; the envelops of the ballooning waves are similar to that of the observed bursty bulk flows moving toward the Earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhRvB..81h5442Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhRvB..81h5442Z"><span id="translatedtitle"><span class="hlt">Electronic</span> and magnetic properties of a BN <span class="hlt">sheet</span> decorated with hydrogen and fluorine</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhou, Jian; Wang, Qian; Sun, Qiang; Jena, Puru</p> <p>2010-02-01</p> <p>First-principles calculations based on density-functional theory reveal some unusual properties of BN <span class="hlt">sheet</span> functionalized with hydrogen and fluorine. These properties differ from those of similarly functionalized graphene even though both share the same honeycomb structure. (1) Unlike graphene which undergoes a metal to insulator transition when fully hydrogenated, the band gap of the BN <span class="hlt">sheet</span> significantly narrows when fully saturated with hydrogen. Furthermore, the band gap of the BN <span class="hlt">sheet</span> can be tuned from 4.7 to 0.6 eV and the system can be a direct or an indirect semiconductor or even a half-metal depending on surface coverage. (2) Unlike graphene, the hydrogenation of BN <span class="hlt">sheet</span> is endothermic. (3) Unlike graphene, BN <span class="hlt">sheet</span> has heteroatomic composition. When codecorated with H and F, it can lead to anisotropic structures with rich <span class="hlt">electronic</span> and magnetic properties. (4) Unlike graphene, BN <span class="hlt">sheets</span> can be made ferromagnetic, antiferromagnetic, or magnetically degenerate depending on how the surface is functionalized. (5) The stability of magnetic coupling of functionalized BN <span class="hlt">sheet</span> can be further modulated by applying external strain. Our study highlights the potential of functionalized BN <span class="hlt">sheets</span> for unusual applications.</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://adsabs.harvard.edu/abs/2015PhyE...74..371M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhyE...74..371M"><span id="translatedtitle"><span class="hlt">Electronic</span> properties of T graphene-like C-BN <span class="hlt">sheets</span>: A density functional theory study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Majidi, R.</p> <p>2015-11-01</p> <p>We have used density functional theory to study the <span class="hlt">electronic</span> properties of T graphene-like C, C-BN and BN <span class="hlt">sheets</span>. The planar T graphene with metallic property has been considered. The results show that the presence of BN has a considerable effect on the <span class="hlt">electronic</span> properties of T graphene. The T graphene-like C-BN and BN <span class="hlt">sheets</span> show semiconducting properties. The energy band gap is increased by enhancing the number of BN units. The possibility of opening and controlling band gap opens the door for T graphene in switchable <span class="hlt">electronic</span> devices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM51E2595P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM51E2595P"><span id="translatedtitle">All-sky imager observations near footprints of <span class="hlt">plasma</span> <span class="hlt">sheet</span> waves with kinetic ballooning-interchange signatures</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.; Nakamura, R.; Sergeev, V. A.; Baumjohann, W.; Kubyshkina, M. V.</p> <p>2015-12-01</p> <p>We collected several THEMIS observations of <span class="hlt">plasma</span> <span class="hlt">sheet</span> oscillations with kinetic ballooning/interchange instability (BICI) signatures. Using an adapted model to find the location of THEMIS footprints, we identified all-sky imager (ASI) observations that may be associated with the waves. The ASI observations reveal a reach activity often being diffuse patchy aurora. We investigate the brightness and motion of the auroral patches and compare them with the BICI activity 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/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> </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://www.osti.gov/scitech/servlets/purl/874126','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/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; Walter, Kevin Carl</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://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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..GECOR2003A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..GECOR2003A"><span id="translatedtitle">Conceptual Design of <span class="hlt">Electron</span>-Beam Generated <span class="hlt">Plasma</span> Tools</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Agarwal, Ankur; Rauf, Shahid; Dorf, Leonid; Collins, Ken; Boris, David; Walton, Scott</p> <p>2015-09-01</p> <p>Realization of the next generation of high-density nanostructured devices is predicated on etching features with atomic layer resolution, no damage and high selectivity. High energy <span class="hlt">electron</span> beams generate <span class="hlt">plasmas</span> with unique features that make them attractive for applications requiring monolayer precision. In these <span class="hlt">plasmas</span>, high energy beam <span class="hlt">electrons</span> ionize the background gas and the resultant daughter <span class="hlt">electrons</span> cool to low temperatures via collisions with gas molecules and lack of any accelerating fields. For example, an <span class="hlt">electron</span> temperature of <0.6 eV with densities comparable to conventional <span class="hlt">plasma</span> sources can be obtained in molecular gases. The chemistry in such <span class="hlt">plasmas</span> can significantly differ from RF <span class="hlt">plasmas</span> as the ions/radicals are produced primarily by beam <span class="hlt">electrons</span> rather than those in the tail of a low energy distribution. In this work, we will discuss the conceptual design of an <span class="hlt">electron</span> beam based <span class="hlt">plasma</span> processing system. <span class="hlt">Plasma</span> properties will be discussed for Ar, Ar/N2, and O2 <span class="hlt">plasmas</span> using a computational <span class="hlt">plasma</span> model, and comparisons made to experiments. The fluid <span class="hlt">plasma</span> model is coupled to a Monte Carlo kinetic model for beam <span class="hlt">electrons</span> which considers gas phase collisions and the effect of electric and magnetic fields on <span class="hlt">electron</span> motion. The impact of critical operating parameters such as magnetic field, beam energy, and gas pressure on <span class="hlt">plasma</span> characteristics in <span class="hlt">electron</span>-beam <span class="hlt">plasma</span> processing systems will be discussed. Partially supported by the NRL base program.</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/servlets/purl/1032746','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1032746"><span id="translatedtitle">Status of <span class="hlt">Plasma</span> <span class="hlt">Electron</span> Hose Instability Studies in FACET</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Adli, Erik; England, Robert Joel; Frederico, Joel; Hogan, Mark; Li, Selina Zhao; Litos, Michael Dennis; Nosochkov, Yuri; An, Weiming; Mori, Warren; /UCLA</p> <p>2011-12-13</p> <p>In the FACET <span class="hlt">plasma</span>-wakefield acceleration experiment a dense 23 GeV <span class="hlt">electron</span> beam will interact with lithium and cesium <span class="hlt">plasmas</span>, leading to <span class="hlt">plasma</span> ion-channel formation. The interaction between the <span class="hlt">electron</span> beam and the <span class="hlt">plasma</span> sheath-<span class="hlt">electrons</span> may lead to a fast growing <span class="hlt">electron</span> hose instability. By using optics dispersion knobs to induce a controlled z-x tilt along the beam entering the <span class="hlt">plasma</span>, we investigate the transverse behavior of the beam in the <span class="hlt">plasma</span> as function of the tilt. We seek to quantify limits on the instability in order to further explore potential limitations on future <span class="hlt">plasma</span> wakefield accelerators due to the <span class="hlt">electron</span> hose instability. The FACET <span class="hlt">plasma</span>-wakefield experiment at SLAC will study beam driven <span class="hlt">plasma</span> wakefield acceleration. A dense 23 GeV <span class="hlt">electron</span> beam will interact with lithium or cesium <span class="hlt">plasma</span>, leading to <span class="hlt">plasma</span> ion-channel formation. The interaction between the <span class="hlt">electron</span> beam and the <span class="hlt">plasma</span> sheath-<span class="hlt">electrons</span> drives the <span class="hlt">electron</span> hose instability, as first studied by Whittum. While Ref. [2] indicates the possibility of a large instability growth rate for typical beam and <span class="hlt">plasma</span> parameters, other studies including have shown that several physical effects may mitigate the hosing growth rate substantially. So far there has been no quantitative benchmarking of experimentally observed hosing in previous experiments. At FACET we aim to perform such benchmarking by for example inducing a controlled z-x tilt along the beamentering the <span class="hlt">plasma</span>, and observing the transverse behavior of the beam in the <span class="hlt">plasma</span> as function. The long-term objective of these studies is to quantify potential limitations on future <span class="hlt">plasma</span> wakefield accelerators due to the <span class="hlt">electron</span> hose instability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM51A2537E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM51A2537E"><span id="translatedtitle">Examining Turbulence in the <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> and its Role in Transport</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>El-Alaoui, M.; Ashour-Abdalla, M.; Lapenta, G.; Richard, R. L.</p> <p>2015-12-01</p> <p>In this study the nature and implications of turbulence in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> is explored with emphasis on large scale and meso-scale processes. The relationship between turbulence and reconnection, and its contribution to magnetospheric transport and dynamics will be evaluated. Observational studies to date have shown that the magnetotail rarely exhibits simple steady convection; instead, flows in the magnetotail have a high level of fluctuations. Flows driven on the scale of the entire system break up into structures that cascade to smaller scales finally reaching scales at which they are dissipated. MHD simulation studies have been carried out both for idealized cases which can be compared to statistical studies of observed events and for event studies where direct comparisons to observations have been made. . In both cases realistic fluctuation spectra were produced in the inertial range. The simulations also do a good job of representing the effects of dissipation and yield dissipative scale lengths that are comparable to those inferred from observations. Turbulence is important at intermediate scales in the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, in particular around dipolarization fronts. We will explore the interaction between large-scale and smaller-scale fluctuations and their contributions to the magnetotail structure. We will use a global MHD simulation and iPIC3D implicit particle in cell simulation to examine how turbulence is related to global and local processes involved in the current <span class="hlt">sheet</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26726645','PUBMED'); return false;" href="https://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="https://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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4431294','PMC'); return false;" href="https://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.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://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/pages/biblio/1305900-electrostatic-gyrokinetic-electron-fully-kinetic-ion-simulation-lower-hybrid-drift-instability-harris-current-sheet','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1305900-electrostatic-gyrokinetic-electron-fully-kinetic-ion-simulation-lower-hybrid-drift-instability-harris-current-sheet"><span id="translatedtitle">3D electrostatic gyrokinetic <span class="hlt">electron</span> and fully kinetic ion simulation of lower-hybrid drift instability of Harris current <span class="hlt">sheet</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Wang, Zhenyu; Lin, Yu; Wang, Xueyi; Tummel, Kurt; Chen, Liu</p> <p>2016-07-07</p> <p>The eigenmode stability properties of three-dimensional lower-hybrid-drift-instabilities (LHDI) in a Harris current <span class="hlt">sheet</span> with a small but finite guide magnetic field have been systematically studied by employing the gyrokinetic <span class="hlt">electron</span> and fully kinetic ion (GeFi) particle-in-cell (PIC) simulation model with a realistic ion-to-<span class="hlt">electron</span> mass ratio mi/me. In contrast to the fully kinetic PIC simulation scheme, the fast <span class="hlt">electron</span> cyclotron motion and <span class="hlt">plasma</span> oscillations are systematically removed in the GeFi model, and hence one can employ the realistic mi/me. The GeFi simulations are benchmarked against and show excellent agreement with both the fully kinetic PIC simulation and the analytical eigenmode theory. Our studies indicate that, for small wavenumbers, ky, along the current direction, the most unstable eigenmodes are peaked at the location wheremore » $$\\vec{k}$$• $$\\vec{B}$$ =0, consistent with previous analytical and simulation studies. Here, $$\\vec{B}$$ is the equilibrium magnetic field and $$\\vec{k}$$ is the wavevector perpendicular to the nonuniformity direction. As ky increases, however, the most unstable eigenmodes are found to be peaked at $$\\vec{k}$$ •$$\\vec{B}$$ ≠0. Additionally, the simulation results indicate that varying mi/me, the current <span class="hlt">sheet</span> width, and the guide magnetic field can affect the stability of LHDI. Simulations with the varying mass ratio confirm the lower hybrid frequency and wave number scalings.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhPl...23g2104W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhPl...23g2104W"><span id="translatedtitle">3D electrostatic gyrokinetic <span class="hlt">electron</span> and fully kinetic ion simulation of lower-hybrid drift instability of Harris 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>Wang, Zhenyu; Lin, Yu; Wang, Xueyi; Tummel, Kurt; Chen, Liu</p> <p>2016-07-01</p> <p>The eigenmode stability properties of three-dimensional lower-hybrid-drift-instabilities (LHDI) in a Harris current <span class="hlt">sheet</span> with a small but finite guide magnetic field have been systematically studied by employing the gyrokinetic <span class="hlt">electron</span> and fully kinetic ion (GeFi) particle-in-cell (PIC) simulation model with a realistic ion-to-<span class="hlt">electron</span> mass ratio mi/me . In contrast to the fully kinetic PIC simulation scheme, the fast <span class="hlt">electron</span> cyclotron motion and <span class="hlt">plasma</span> oscillations are systematically removed in the GeFi model, and hence one can employ the realistic mi/me . The GeFi simulations are benchmarked against and show excellent agreement with both the fully kinetic PIC simulation and the analytical eigenmode theory. Our studies indicate that, for small wavenumbers, ky, along the current direction, the most unstable eigenmodes are peaked at the location where k →.B → =0 , consistent with previous analytical and simulation studies. Here, B → is the equilibrium magnetic field and k → is the wavevector perpendicular to the nonuniformity direction. As ky increases, however, the most unstable eigenmodes are found to be peaked at k →.B → ≠0 . In addition, the simulation results indicate that varying mi/me , the current <span class="hlt">sheet</span> width, and the guide magnetic field can affect the stability of LHDI. Simulations with the varying mass ratio confirm the lower hybrid frequency and wave number scalings.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22489971','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22489971"><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://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sydorenko, D.; Kaganovich, I. D.; Chen, L.; Ventzek, P. L. G.</p> <p>2015-12-15</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/2006AIPC..808..235Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AIPC..808..235Z"><span id="translatedtitle"><span class="hlt">Electron</span> Beam Emission Characteristics from <span class="hlt">Plasma</span> Focus Devices</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, T.; Patran, A.; Wong, D.; Hassan, S. M.; Springham, S. V.; Tan, T. L.; Lee, P.; Lee, S.; Rawat, R. S.</p> <p>2006-01-01</p> <p>In this paper we observed the characteristics of the <span class="hlt">electron</span> beam emission from our <span class="hlt">plasma</span> focus machine filling neon, argon, helium and hydrogen. Rogowski coil and CCD based magnetic spectrometer were used to obtain temporal and energy distribution of <span class="hlt">electron</span> emission. And the preliminary results of deposited FeCo thin film using <span class="hlt">electron</span> beam from our <span class="hlt">plasma</span> focus device were presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22043521','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22043521"><span id="translatedtitle">Cerenkov and cyclotron Cerenkov instabilities in a dielectric loaded parallel plate waveguide <span class="hlt">sheet</span> <span class="hlt">electron</span> beam system</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhao Ding; Ding Yaogen</p> <p>2011-09-15</p> <p>A dielectric loaded parallel plate waveguide <span class="hlt">sheet</span> <span class="hlt">electron</span> beam system can be taken as a reliable model for the practical dielectric loaded rectangular waveguide <span class="hlt">sheet</span> beam system that has a transverse cross section with a large width to height ratio. By using kinetic theory, the dispersion equations for Cerenkov and cyclotron Cerenkov instabilities in the parallel plate waveguide <span class="hlt">sheet</span> beam system have been obtained rigorously. The dependences of the growth rate of both instabilities on the electric and structural parameters have also been investigated in detail through numerical calculations. It is worthwhile to point out that adopting an <span class="hlt">electron</span> beam with transverse velocity can evidently improve the growth rate of Cerenkov instability, which seems like the case of cyclotron Cerenkov instability.</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('https://www.ncbi.nlm.nih.gov/pubmed/26465570','PUBMED'); return false;" href="https://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="https://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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/15006468','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/15006468"><span id="translatedtitle"><span class="hlt">Electronic</span> Structure of Dense <span class="hlt">Plasmas</span> by X-Ray Scattering</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gregori, G; Glenzer, S H; Rogers, F J; Pollaine, S M; Froula, D H; Blancard, C; Faussurier, G; Renaudin, P; Kuhlbrodt, S; Redmer, R; Landen, O L</p> <p>2003-10-07</p> <p>We present an improved analytical expression for the x-ray dynamic structure factor from a dense <span class="hlt">plasma</span> which includes the effects of weakly bound <span class="hlt">electrons</span>. This result can be applied to describe scattering from low to moderate Z <span class="hlt">plasmas</span>, and it covers the entire range of <span class="hlt">plasma</span> conditions that can be found in inertial confinement fusion experiments, from ideal to degenerate up to moderately coupled systems. We use our theory to interpret x-ray scattering experiments from solid density carbon <span class="hlt">plasma</span> and to extract accurate measurements of <span class="hlt">electron</span> temperature, <span class="hlt">electron</span> density and charge state. We use our experimental results to validate various equation-of-state models for carbon <span class="hlt">plasmas</span>.</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://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009AGUFMSM13E..07L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009AGUFMSM13E..07L&link_type=ABSTRACT"><span id="translatedtitle">Connections between large-scale transport to the inner magnetosphere from the distant <span class="hlt">plasma</span> <span class="hlt">sheet</span>, region 2 coupling to the ionosphere, and substorm and storm dynamics (Invited)</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.; Wang, C.; Zou, S.; Gkioulidou, M.; Nishimura, Y.; Shi, Y.; Kim, H.; Xing, X.; Nicolls, M. J.; Heinselman, C. J.</p> <p>2009-12-01</p> <p>Studies using a variety of ground-based and spacecraft observations, as well as the Rice Convection Model, have taught us much about the connection between <span class="hlt">plasma</span> <span class="hlt">sheet</span> transport and particle distributions within the inner <span class="hlt">plasma</span> <span class="hlt">sheet</span>. These studies have shown that <span class="hlt">plasma</span> moves earthward (equatorward in the ionosphere) after enhancements in convection to reach the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span>, leading to the enhancements in <span class="hlt">plasma</span> <span class="hlt">sheet</span> pressure that are responsible for the growth phase of substorms and the partial ring current. The highest inner <span class="hlt">plasma</span> <span class="hlt">sheet</span> pressures likely occur in the subauroral polarization streams (SAPS) region of the evening-side convection cell, lying equatorward of the Harang reversal. Both the Harang reversal and SAPS are manifestations of the region 2 (R2) electrodynamical coupling, so that transport to the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> is strongly influenced by the R2 magnetosphere-ionosphere coupling. Modeling results show that this transport, together with the concurrent R2 coupling, is also strongly dependent on the <span class="hlt">plasma</span> distributions that enter the <span class="hlt">plasma</span> <span class="hlt">sheet</span>. However, the entering <span class="hlt">plasma</span> distribution is expected to have substantial spatial and temporal structure, which should impart substantial spatial structure and time dependencies to the inner <span class="hlt">plasma</span> <span class="hlt">sheet</span> particle distributions. In addition, very recent analyses indicate that the temporal variations of the particle distribution entering the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, and the ensuing transport of new particle distributions within the <span class="hlt">plasma</span> <span class="hlt">sheet</span>, is fundamental to understanding the substorm expansion phase. Taken together, the above results indicate that an important understanding of inner magnetosphere particle distributions and their dynamics, as well as of major geomagnetic disturbances, is likely to come from integrated studies of <span class="hlt">plasma</span> <span class="hlt">sheet</span> particle entry, particle transport, and electrodynamical coupling to the ionosphere.</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://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.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('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4451805','PMC'); return false;" href="https://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> (α-P, β-P,γ-P and δ-P) using density functional theory combined with Boltzmann transport method and relaxation time approximation. It is shown that α-P, β-P and γ-P are indirect gap semiconductors, while δ-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, α-P, γ-P and δ-P <span class="hlt">sheets</span> can be considered as n-type semiconductors, and β-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.osti.gov/scitech/biblio/22486421','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22486421"><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://www.osti.gov/scitech">SciTech Connect</a></p> <p>Allanson, O. Neukirch, T. Wilson, F. Troscheit, S.</p> <p>2015-10-15</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://ntrs.nasa.gov/search.jsp?R=19810025909&hterms=Planck+Max&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3D%2528Planck%252C%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%3D90%26Ntt%3D%2528Planck%252C%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://www.ncbi.nlm.nih.gov/pubmed/27610861','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27610861"><span id="translatedtitle">Laboratory Observation of Resistive <span class="hlt">Electron</span> Tearing in a Two-Fluid Reconnecting Current <span class="hlt">Sheet</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jara-Almonte, Jonathan; Ji, Hantao; Yamada, Masaaki; Yoo, Jongsoo; Fox, William</p> <p>2016-08-26</p> <p>The spontaneous formation of plasmoids via the resistive <span class="hlt">electron</span> tearing of a reconnecting current <span class="hlt">sheet</span> is observed in the laboratory. These experiments are performed during driven, antiparallel reconnection in the two-fluid regime within the Magnetic Reconnection Experiment. It is found that plasmoids are present even at a very low Lundquist number, and the number of plasmoids scales with both the current <span class="hlt">sheet</span> aspect ratio and the Lundquist number. The reconnection electric field increases when plasmoids are formed, leading to an enhanced reconnection rate. PMID:27610861</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://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://www.osti.gov/scitech/servlets/purl/909294','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/909294"><span id="translatedtitle">Emittance 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, N.; Berry, M.; Blumenfeld, I.; Decker, F.-J.; Hogan, M.J.; Ischebeck, R.; Iverson, R.; Siemann, R.; Walz, D.; Clayton, C.E.; Huang, C.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.B.; Zhou, M.; Katsouleas, T.C.; Muggli, P.; Oz, E.; /Southern California U.</p> <p>2007-06-28</p> <p>Recent <span class="hlt">electron</span> beam driven <span class="hlt">plasma</span> wakefield accelerator experiments carried out at SLAC showed trapping of <span class="hlt">plasma</span> <span class="hlt">electrons</span>. These trapped <span class="hlt">electrons</span> appeared on an energy spectrometer with smaller transverse size than the beam driving the wake. A connection is made between transverse size and emittance; due to the spectrometer's resolution, this connection allows for placing an upper limit on the trapped <span class="hlt">electron</span> emittance. The upper limit for the lowest normalized emittance measured in the experiment is 1 mm {center_dot} mrad.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21532143','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21532143"><span id="translatedtitle"><span class="hlt">Electron</span>-acoustic solitary waves in a nonextensive <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tribeche, Mouloud; Djebarni, Lyes</p> <p>2010-12-15</p> <p>The problem of arbitrary amplitude <span class="hlt">electron</span>-acoustic solitary waves (EASWs) in a <span class="hlt">plasma</span> having cold fluid <span class="hlt">electrons</span>, hot nonextensive <span class="hlt">electrons</span>, and stationary ions is addressed. It is found that the 'Maxwellianization' process of the hot nonextensive component does not favor the propagation of the EASWs. In contrast to superthermality, nonextensivity makes the <span class="hlt">electron</span>-acoustic solitary structure less spiky. Our theoretical analysis brings a possibility to develop more refined theories of nonlinear solitary structures in astrophysical <span class="hlt">plasmas</span>.</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://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/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://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014ApSS..295..137T&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014ApSS..295..137T&link_type=ABSTRACT"><span id="translatedtitle">Theoretical study of the adsorption of CHO radicals on hexagonal boron nitride <span class="hlt">sheet</span>: Structural and <span class="hlt">electronic</span> changes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tian, Yu; Pan, Xiao-fan; Liu, Yue-jie; Zhao, Jing-xiang</p> <p>2014-03-01</p> <p>It is well known that pristine hexagonal boron nitride <span class="hlt">sheet</span> (h-BN <span class="hlt">sheet</span>) exhibits large insulating band gap, thus hindering its application to some extent. In this regard, surface chemisorption of certain groups on h-BN <span class="hlt">sheet</span> is shown to be the most popular method to tune its band gap and thus modify its <span class="hlt">electronic</span> properties. In the present work, we performed density functional theory (DFT) calculations to study the adsorption of CHO radicals with different coverages on h-BN <span class="hlt">sheet</span>. Particular attention is paid to explore the effects of CHO adsorption on the geometrical structures and <span class="hlt">electronic</span> properties of h-BN <span class="hlt">sheet</span>. The results indicate that the adsorption of a single CHO radical on pristine h-BN <span class="hlt">sheet</span> is very weak with a negligible adsorption energy (-0.09 eV). In contrast, upon adsorption of more CHO radicals on h-BN <span class="hlt">sheet</span>, these adsorbates prefer to adsorb in pairs on the B and the nearest N atoms from both sides of h-BN <span class="hlt">sheet</span>. An energy diagram of the average adsorption energy of CHO radicals on h-BN <span class="hlt">sheet</span> as a function of its coverage indicates that up to 20 CHO radicals (40%) can be attached to h-BN <span class="hlt">sheet</span> with the adsorption energy of -0.29 eV. More importantly, the adsorption of CHO radicals can induce certain impurity states within the band gap of h-BN <span class="hlt">sheet</span>, thus reducing the band gap and enhancing its electrical conductivity.</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.osti.gov/scitech/biblio/22089356','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22089356"><span id="translatedtitle">Generating <span class="hlt">electron</span> cyclotron resonance <span class="hlt">plasma</span> using distributed scheme</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Huang, C. C.; Chang, T. H.; Chen, N. C.; Chao, H. W.; Chen, C. C.; Chou, S. F.</p> <p>2012-08-06</p> <p>This study employs a distributed microwave input system and permanent magnets to generate large-area <span class="hlt">electron</span> cyclotron resonance (ECR) <span class="hlt">plasma</span>. ECR <span class="hlt">plasmas</span> were generated with nitrogen gas, and the <span class="hlt">plasma</span> density was measured by Langmuir probe. A uniform ECR <span class="hlt">plasma</span> with the <span class="hlt">electron</span> density fluctuation of {+-}9.8% over 500 mm Multiplication-Sign 500 mm was reported. The proposed idea of generating uniform ECR <span class="hlt">plasma</span> can be scaled to a much larger area by using n Multiplication-Sign n microwave input array system together with well-designed permanent magnets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24401149','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24401149"><span id="translatedtitle">Nonnuclear nearly free <span class="hlt">electron</span> conduction channels induced by doping charge in nanotube-molecular <span class="hlt">sheet</span> composites.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhao, Jin; Zheng, Qijing; Petek, Hrvoje; Yang, Jinlong</p> <p>2014-09-01</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. PMID:24401149</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26573995','PUBMED'); return false;" href="https://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="https://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>2015-12-21</p> <p>Three two-dimensional phosphorus nitride (PN) monolayer <span class="hlt">sheets</span> (named as α-, β-, and γ-PN, respectively) with fantastic structures and properties are predicted based on first-principles calculations. The α-PN and γ-PN have a buckled structure, whereas β-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 α-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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5046188','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5046188"><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://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2015-01-01</p> <p>Abstract 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>. PMID:27722039</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19990116091&hterms=whistler&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dwhistler','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19990116091&hterms=whistler&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dwhistler"><span id="translatedtitle">Whistler Solitons in <span class="hlt">Plasma</span> with Anisotropic Hot <span class="hlt">Electron</span> Admixture</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.; Krivorutsky, E. N.; Gallagher, D. L.</p> <p>1999-01-01</p> <p>The longitudinal and transverse modulation instability of whistler waves in <span class="hlt">plasma</span>, with a small admixture of hot anisotropic <span class="hlt">electrons</span>, is discussed. If the hot particles temperature anisotropy is positive, it is found that, in such <span class="hlt">plasma</span>, longitudinal perturbations can lead to soliton formation for frequencies forbidden in cold <span class="hlt">plasma</span>. The soliton is enriched by hot particles. The frequency region unstable to transverse modulation in cold <span class="hlt">plasma</span> in the presence of hot <span class="hlt">electrons</span> is divided by stable domains. For both cases the role of hot <span class="hlt">electrons</span> is more significant for whistlers with smaller frequencies.</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://www.osti.gov/scitech/servlets/purl/102443','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/102443"><span id="translatedtitle">UV laser ionization and <span class="hlt">electron</span> beam diagnostics for <span class="hlt">plasma</span> lenses</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Govil, R.; Volfbeyn, P.; Leemans, W.</p> <p>1995-04-01</p> <p>A comprehensive study of focusing of relativistic <span class="hlt">electron</span> beams with overdense and underdense <span class="hlt">plasma</span> lenses requires careful control of <span class="hlt">plasma</span> density and scale lengths. <span class="hlt">Plasma</span> lens experiments are planned at the Beam Test Facility of the LBL Center for Beam Physics, using the 50 MeV <span class="hlt">electron</span> beam delivered by the linac injector from the Advanced Light Source. Here we present results from an interferometric study of <span class="hlt">plasmas</span> produced in tri-propylamine vapor with a frequency quadrupled Nd:YAG laser at 266 nm. To study temporal dynamics of <span class="hlt">plasma</span> lenses we have developed an <span class="hlt">electron</span> beam diagnostic using optical transition radiation to time resolve beam size and divergence. <span class="hlt">Electron</span> beam ionization of the <span class="hlt">plasma</span> has also been investigated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhDT........42N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhDT........42N"><span id="translatedtitle">Measurements of <span class="hlt">plasma</span> bremsstrahlung and <span class="hlt">plasma</span> energy density produced by <span class="hlt">electron</span> cyclotron resonance ion source <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>Noland, Jonathan David</p> <p>2011-12-01</p> <p>The goal of this dissertation was to gain an understanding on the relative importance of microwave power, neutral pressure, and magnetic field configuration on the behavior of the hot <span class="hlt">electrons</span> within an <span class="hlt">Electron</span> Cyclotron Resonance Ion Source (ECRIS) <span class="hlt">plasma</span>. This was carried out through measurement of <span class="hlt">plasma</span> bremsstrahlung with both NaI(Tl) (hv > 30 keV) and CdTe (2 keV < hv < 70 keV) x-ray detectors, and through measurement of the <span class="hlt">plasma</span> energy density with a diamagnetic loop placed around the <span class="hlt">plasma</span> chamber. We also examined the anisotropy in x-ray power by simultaneously measuring the x-ray spectra in two orthogonal directions: radially and axially, using NaI(Tl) detectors. We have seen that for a 6.4 GHz ECRIS, both the x-ray power produced by confined <span class="hlt">electrons</span> and the <span class="hlt">plasma</span> energy density behave logarithmically with microwave power. The x-ray flux created by <span class="hlt">electrons</span> lost from the <span class="hlt">plasma</span>, however, does not saturate. Thus, the small increase in <span class="hlt">plasma</span> density that occurred at high microwave powers (> 150 W on a 6.4 GHz ECRIS) was accompanied by a large increase in total x-ray power. We suggest that the saturation of x-ray power and <span class="hlt">plasma</span> energy density was due to rf-induced pitch-angle scattering of the <span class="hlt">electrons</span>. X-ray power and <span class="hlt">plasma</span> energy density were also shown to saturate with neutral pressure, and to increase nearly linearly as the gradient of the magnetic field in the resonance zone was decreased. All of these findings were in agreement with the theoretical models describing ECRIS <span class="hlt">plasmas</span>. We have discussed the use of a diamagnetic loop as a means of exploring various <span class="hlt">plasma</span> time scales on a relative basis. Specifically, we focused much of our attention on studying how changing ion source parameters, such as microwave power and neutral pressure, would effect the rise and decay of the integrated diamagnetic signal, which can be related to <span class="hlt">plasma</span> energy density. We showed that increasing microwave power lowers the e-fold times at both the leading</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SoPh..289.1607Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SoPh..289.1607Z"><span id="translatedtitle"><span class="hlt">Electron</span> Acceleration in a Dynamically Evolved Current <span class="hlt">Sheet</span> Under Solar Coronal Conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Shaohua; Du, A. M.; Feng, Xueshang; Cao, Xin; Lu, Quanming; Yang, Liping; Chen, Gengxiong; Zhang, Ying</p> <p>2014-05-01</p> <p><span class="hlt">Electron</span> acceleration in a drastically evolved current <span class="hlt">sheet</span> under solar coronal conditions is investigated via the combined 2.5-dimensional (2.5D) resistive magnetohydrodynamics (MHD) and test-particle approaches. Having a high magnetic Reynolds number (105), the long, thin current <span class="hlt">sheet</span> is torn into a chain of magnetic islands, which grow in size and coalesce with each other. The acceleration of <span class="hlt">electrons</span> is explored in three typical evolution phases: when several large magnetic islands are formed (phase 1), two of these islands are approaching each other (phase 2), and almost merging into a "monster" magnetic island (phase 3). The results show that for all three phases <span class="hlt">electrons</span> with an initial Maxwell distribution evolve into a heavy-tailed distribution and more than 20 % of the <span class="hlt">electrons</span> can be accelerated higher than 200 keV within 0.1 second and some of them can even be energized up to MeV ranges. The lower-energy <span class="hlt">electrons</span> are located away from the magnetic separatrices and the higher-energy <span class="hlt">electrons</span> are inside the magnetic islands. The most energetic <span class="hlt">electrons</span> have a tendency to be around the outer regions of the magnetic islands or to appear in the small secondary magnetic islands. It is the trapping effect of the magnetic islands and the distributions of E p that determine the acceleration and spatial distributions of the energetic <span class="hlt">electrons</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22038512','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22038512"><span id="translatedtitle">Physics of laser-driven <span class="hlt">plasma</span>-based <span class="hlt">electron</span> accelerators</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Esarey, E.; Schroeder, C. B.; Leemans, W. P.</p> <p>2009-07-15</p> <p>Laser-driven <span class="hlt">plasma</span>-based accelerators, which are capable of supporting fields in excess of 100 GV/m, are reviewed. This includes the laser wakefield accelerator, the <span class="hlt">plasma</span> beat wave accelerator, the self-modulated laser wakefield accelerator, <span class="hlt">plasma</span> waves driven by multiple laser pulses, and highly nonlinear regimes. The properties of linear and nonlinear <span class="hlt">plasma</span> waves are discussed, as well as <span class="hlt">electron</span> acceleration in <span class="hlt">plasma</span> waves. Methods for injecting and trapping <span class="hlt">plasma</span> <span class="hlt">electrons</span> in <span class="hlt">plasma</span> waves are also discussed. Limits to the <span class="hlt">electron</span> energy gain are summarized, including laser pulse diffraction, <span class="hlt">electron</span> dephasing, laser pulse energy depletion, and beam loading limitations. The basic physics of laser pulse evolution in underdense <span class="hlt">plasmas</span> is also reviewed. This includes the propagation, self-focusing, and guiding of laser pulses in uniform <span class="hlt">plasmas</span> and with preformed density channels. Instabilities relevant to intense short-pulse laser-<span class="hlt">plasma</span> interactions, such as Raman, self-modulation, and hose instabilities, are discussed. Experiments demonstrating key physics, such as the production of high-quality <span class="hlt">electron</span> bunches at energies of 0.1-1 GeV, are summarized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21069917','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21069917"><span id="translatedtitle">Flying mirror model for interaction of a super-intense nonadiabatic laser pulse with a thin <span class="hlt">plasma</span> layer: Dynamics of <span class="hlt">electrons</span> in a linearly polarized external field</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kulagin, Victor V.; Cherepenin, Vladimir A.; Hur, Min Sup; Suk, Hyyong</p> <p>2007-11-15</p> <p>Interaction of a high-power laser pulse having a sharp front with a thin <span class="hlt">plasma</span> layer is considered. General one-dimensional numerical-analytical model is elaborated, in which the <span class="hlt">plasma</span> layer is represented as a large collection of <span class="hlt">electron</span> <span class="hlt">sheets</span>, and a radiation reaction force is derived analytically. Using this model, trajectories of the <span class="hlt">electrons</span> of the <span class="hlt">plasma</span> layer are calculated numerically and compared with the <span class="hlt">electron</span> trajectories obtained in particle-in-cell simulations, and a good agreement is found. Two simplified analytical models are considered, in which only one <span class="hlt">electron</span> <span class="hlt">sheet</span> is used, and it moves transversely and longitudinally in the fields of an ion <span class="hlt">sheet</span> and a laser pulse (longitudinal displacements along the laser beam axis can be considerably larger than the laser wavelength). In the model I, a radiation reaction is included self-consistently, while in the model II a radiation reaction force is omitted. For the two models, analytical solutions for the dynamical parameters of the <span class="hlt">electron</span> <span class="hlt">sheet</span> in a linearly polarized laser pulse are derived and compared with the numerical solutions for the central <span class="hlt">electron</span> <span class="hlt">sheet</span> (positioned initially in the center) of the real <span class="hlt">plasma</span> layer, which are calculated from the general numerical-analytical model. This comparison shows that the model II gives better description for the trajectory of the central <span class="hlt">electron</span> <span class="hlt">sheet</span> of the real <span class="hlt">plasma</span> layer, while the model I gives more adequate description for a transverse momentum. Both models show that if the intensity of the laser pulse is high enough, even in the field with a constant amplitude, the <span class="hlt">electrons</span> undergo not only the transverse oscillations with the period of the laser field, but also large (in comparison with the laser wavelength) longitudinal oscillations with the period, defined by the system parameters and initial conditions of particular oscillation.</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/cgi-bin/nph-data_query?bibcode=2012APS..DPPNP8005A&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012APS..DPPNP8005A&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Electron</span> Acoustic Waves in Pure 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>Anderegg, F.; Affolter, M.; Driscoll, C. F.; O'Neil, T. M.; Valentini, F.</p> <p>2012-10-01</p> <p><span class="hlt">Electron</span> Acoustic Waves (EAWs) are the low-frequency branch of near-linear Langmuir (<span class="hlt">plasma</span>) waves: the frequency is such that the complex dielectric function (Dr, Di) has Dr= 0; and ``flattening'' of f(v) near the wave phase velocity vph gives Di=0 and eliminates Landau damping. Here, we observe standing axisymmetric EAWs in a pure ion column.footnotetextF. Anderegg, et al., Phys. Rev. Lett. 102, 095001 (2009). At low excitation amplitudes, the EAWs have vph˜1.4 v, in close agreement with near-linear theory. At moderate excitation strengths, EAW waves are observed over a range of frequencies, with 1.3 v < vph< 2.1 v. Here, the final wave frequency may differ from the excitation frequency since the excitation modifies f (v); and recent theory analyzes frequency shifts from ``corners'' of a plateau at vph.footnotetextF. Valentini et al., arXiv:1206.3500v1. Large amplitude EAWs have strong phase-locked harmonic content, and experiments will be compared to same-geometry simulations, and to simulations of KEENfootnotetextB. Afeyan et al., Proc. Inertial Fusion Sci. and Applications 2003, A.N.S. Monterey (2004), p. 213. waves in HEDLP geometries.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/398304','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/398304"><span id="translatedtitle">Radial evolution of the finite-width <span class="hlt">plasma</span> <span class="hlt">sheet</span> in a Z-pinch -- A parametric analysis based on conservation laws</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sherar, A.G.</p> <p>1996-10-01</p> <p>An algebraic method to compute the macroscopic radial-averaged quantities (thickness, density, radial velocity) of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> in the first compression of simple z-pinches is presented. Following the snowplow model, a set of MHD equations is written in a reference system in which the internal boundary of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> is at rest. The magnetic pressure and the energy losses are both modeled as functions of the radius of the <span class="hlt">sheet</span>, and a time-independent algebraic equation is obtained. Finding the roots of this expression, the thickness of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> as a function of its radius can be computed. The temporal evolution of all the quantities of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> can also be obtained making an appropriate change to the reference system. Computed values of the temperature of the <span class="hlt">sheet</span> are in agreement with experimental values. The ranges of validity for the numerical values of the modeling parameters are analyzed.</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 Nanotube–Molecular <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 electron–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://www.ncbi.nlm.nih.gov/pubmed/22068843','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22068843"><span id="translatedtitle">First-principles study of <span class="hlt">electronic</span> and magnetic properties of transition metal adsorbed h-BNC2 <span class="hlt">sheets</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Srivastava, Pooja; Deshpande, Mrinalini; Sen, Prasenjit</p> <p>2011-12-28</p> <p>Adsorption of Fe, Co and Ni atoms on a hybrid hexagonal <span class="hlt">sheet</span> of graphene and boron nitride is studied using density functional methods. Most favorable adsorption sites for these adatoms are identified for different widths of the graphene and boron nitride regions. <span class="hlt">Electronic</span> structure and magnetic properties of the TM-adsorbed <span class="hlt">sheets</span> are then studied in detail. The TM atoms change the <span class="hlt">electronic</span> structure of the <span class="hlt">sheet</span> significantly, and the resulting system can be a magnetic semiconductor, semi-metal, or a non-magnetic semiconductor depending on the TM chosen. This gives tunability of properties which can be useful in novel <span class="hlt">electronics</span> applications. Finally, barriers for diffusion of the adatoms on the <span class="hlt">sheet</span> are calculated, and their tendency to agglomerate on the <span class="hlt">sheet</span> is estimated. PMID:22068843</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EPJD...68..260M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EPJD...68..260M"><span id="translatedtitle">Resistive collimation of <span class="hlt">electron</span> beams in relativistic and 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>Mahdavi, M.; Khodadadi Azadboni, F.</p> <p>2014-09-01</p> <p>The purpose of this research is the study of the effects of <span class="hlt">plasma</span> state and fiber on collimating relativistic <span class="hlt">electron</span> beam in fast ignition. In this paper, for collimating relativistic <span class="hlt">electrons</span> produced at the laser <span class="hlt">plasma</span> interaction, a thin fiber of aluminum, lithium or CH either in the classical, degenerate or relativistic <span class="hlt">plasma</span> states is considered. The fast <span class="hlt">electron</span> beam could be collimated down to radii of 10 μm, in that case, the best results are achieved when there is a sharp transition in resistance. This ensures that the correct magnetic growth rate is used for hot <span class="hlt">electrons</span> at different energy levels. Calculations show that the resistivity of the material surrounding the CH fiber in the degenerate <span class="hlt">plasma</span> is smaller than that for classical and relativistic <span class="hlt">plasma</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006APS..DPPCP1126K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006APS..DPPCP1126K&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Electron</span> acceleration in long scale 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>Kamperidis, Christos; Mangles, Stuart P. D.; Nagel, Sabrina R.; Bellei, Claudio; Krushelnick, Karl; Najmudin, Zulfikar; Bourgeois, Nicola; Marques, Jean Raphael; Kaluza, Malte C.</p> <p>2006-10-01</p> <p>Broad energy <span class="hlt">electron</span> bunches are produced through the Self-Modulated Laser Wakefield Acceleration scheme at the 30J, 300 fsec laser, LULI, France, with long scale underdense <span class="hlt">plasmas</span>, created in a He filled gas cell and in He gas jet nozzles of various lengths. With c.τlaser>>λ<span class="hlt">plasma</span>, <span class="hlt">electrons</span> reached Emax ˜ 200MeV. By carefully controlling the dynamics of the interaction and by simultaneous observations of the <span class="hlt">electron</span> energy spectra and the forward emitted optical spectrum, we found that a <span class="hlt">plasma</span> density threshold (˜5.10^18 cm-3) exists for quasi-monoenergetic (˜30MeV) features to appear. The overall <span class="hlt">plasma</span> channel size was inferred from the collected Thomson scattered light. 2D PIC simulations indicate that the main long laser pulse breaks up into small pulselets that eventually get compressed and tightly focused inside the first few <span class="hlt">plasma</span> periods, leading to a bubble like acceleration of <span class="hlt">electron</span> bunches.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1235552','SCIGOV-DOEDE'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1235552"><span id="translatedtitle">Public Data Set: Impedance of an Intense <span class="hlt">Plasma</span>-Cathode <span class="hlt">Electron</span> Source for Tokamak <span class="hlt">Plasma</span> Startup</span></a></p> <p><a target="_blank" href="http://www.osti.gov/dataexplorer">DOE Data Explorer</a></p> <p>Hinson, Edward T. [University of Wisconsin-Madison] (ORCID:000000019713140X); Barr, Jayson L. [University of Wisconsin-Madison] (ORCID:0000000177685931); Bongard, Michael W. [University of Wisconsin-Madison] (ORCID:0000000231609746); Burke, Marcus G. [University of Wisconsin-Madison] (ORCID:0000000176193724); Fonck, Raymond J. [University of Wisconsin-Madison] (ORCID:0000000294386762); Perry, Justin M. [University of Wisconsin-Madison] (ORCID:0000000171228609)</p> <p>2016-05-31</p> <p>This data set contains openly-documented, machine readable digital research data corresponding to figures published in E.T. Hinson et al., 'Impedance of an Intense <span class="hlt">Plasma</span>-Cathode <span class="hlt">Electron</span> Source for Tokamak <span class="hlt">Plasma</span> Startup,' Physics of <span class="hlt">Plasmas</span> 23, 052515 (2016).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22490697','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22490697"><span id="translatedtitle">Progress toward positron-<span class="hlt">electron</span> pair <span class="hlt">plasma</span> experiments</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Stenson, E. V.; Stanja, J.; Hergenhahn, U.; Saitoh, H.; Niemann, H.; Pedersen, T. Sunn; Marx, G. H.; Schweikhard, L.; Danielson, J. R.; Surko, C. M.; Hugenschmidt, C.</p> <p>2015-06-29</p> <p><span class="hlt">Electron</span>-positron <span class="hlt">plasmas</span> have been of theoretical interest for decades, due to the unique <span class="hlt">plasma</span> physics that arises from all charged particles having precisely identical mass. It is only recently, though, that developments in non-neutral <span class="hlt">plasma</span> physics (both in linear and toroidal geometries) and in the flux of sources for cold positrons have brought the goal of conducting <span class="hlt">electron</span>-positron pair <span class="hlt">plasma</span> experiments within reach. The APEX/PAX collaboration is working on a number of projects in parallel toward that goal; this paper provides an overview of recent, current, and upcoming activities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004GeoRL..31.8801S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004GeoRL..31.8801S"><span id="translatedtitle">Three separate ion populations observed simultaneously in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer in the distant geomagnetic tail</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saito, Yoshifumi; Mukai, Toshifumi; Terasawa, Toshio; Machida, Shinobu</p> <p>2004-04-01</p> <p>The detailed structure of ion velocity space distributions in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> boundary layer (PSBL) in the distant geomagnetic tail has been investigated. Three separate, tailward-streaming ion populations have been observed simultaneously in PSBL crossings in which the inner edge of the PSBL was identified as a slow mode shock: cold, low-energy, ions presumably of ionospheric origin that fill much of the tail lobes, and two more energetic populations. The more energetic of these latter populations, which was concentrated in the outer (lobe) layers of the PSBL, had a ``kidney bean'' shape. The less energetic population had a well-defined low-energy cutoff that decreased with increasing penetration into the PSBL from the lobe. The sources of these two populations may be cold lobe ions accelerated in the current <span class="hlt">sheet</span> near the distant neutral line and <span class="hlt">plasma</span> <span class="hlt">sheet</span> ions that leak across the shock, respectively.</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 Alfvén 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 Alfvén speed. For a hot EP <span class="hlt">plasma</span>, the existence range depends on the Alfvén 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/2012AGUFMSH21A2193S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMSH21A2193S"><span id="translatedtitle"><span class="hlt">Electron</span> Acceleration in a Dynamically Evolved Current <span class="hlt">Sheet</span> of Solar Coronal Conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shaohua, Z.; Du, A.; Feng, X.</p> <p>2012-12-01</p> <p><span class="hlt">Electron</span> acceleration in a drastically evolved current <span class="hlt">sheet</span> of solar coronal conditions is investigated via the combined resistive Magnetohydrodynamics (MHD) and test particle approaches. With high magnetic Reynolds number, the long-thin current <span class="hlt">sheet</span> is tearing into a chain of magnetic islands, which grow in size and coalesce together. The acceleration of <span class="hlt">electrons</span> are explored in three typical evolvement phases: when several large magnetic islands are formed (phase1), two of them are approaching each other (phase2) and almost merging into a "monster" magnetic island (phase3). The results show that for all the three phases <span class="hlt">electrons</span> with an initially Maxwellian distribution evolve into a heavy-tailed distribution and more than 20% of the <span class="hlt">electrons</span> can be accelerated higher than 200 keV within 0.1 second and some of them can even be energized up to MeV ranges. Most of the energetic <span class="hlt">electrons</span> move around the magnetic islands in clockwise direction (anti-parallel to the magnetic field lines), drifting in the -Z direction. The energetic <span class="hlt">electrons</span> with 10 keV < Ek < 200 keV are located outside the magnetic separatrices, where parallel electric field (Ep) is small. The <span class="hlt">electrons</span> with 200 keV < Ek < 5000 keV are distributed inside the magnetic islands where Ep is moderate large but have complex structures. The <span class="hlt">electrons</span> with Ek > 5000 keV are located around the outer regions of the magnetic islands or at the core regions of the magnetic islands. Some of the most energetic <span class="hlt">electrons</span> even appear in the small secondary magnetic islands that are embedded in the diusion regions in between the magnetic islands. It is the trapping eect of the magnetic islands and the distributions of Ep that determine the acceleration processes and space distribution of the energetic <span class="hlt">electrons</span>.</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://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://www.osti.gov/scitech/biblio/22489826','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22489826"><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://www.osti.gov/scitech">SciTech Connect</a></p> <p>Akbari-Moghanjoughi, M.; Ghorbanalilu, M.</p> <p>2015-11-15</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> </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://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.ncbi.nlm.nih.gov/pubmed/27176413','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27176413"><span id="translatedtitle"><span class="hlt">Plasma</span> scale-length effects on <span class="hlt">electron</span> energy spectra in high-irradiance laser <span class="hlt">plasmas</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Culfa, O; Tallents, G J; Rossall, A K; Wagenaars, E; Ridgers, C P; Murphy, C D; Dance, R J; Gray, R J; McKenna, P; Brown, C D R; James, S F; Hoarty, D J; Booth, N; Robinson, A P L; Lancaster, K L; Pikuz, S A; Faenov, A Ya; Kampfer, T; Schulze, K S; Uschmann, I; Woolsey, N C</p> <p>2016-04-01</p> <p>An analysis of an <span class="hlt">electron</span> spectrometer used to characterize fast <span class="hlt">electrons</span> generated by ultraintense (10^{20}Wcm^{-2}) laser interaction with a preformed <span class="hlt">plasma</span> of scale length measured by shadowgraphy is presented. The effects of fringing magnetic fields on the <span class="hlt">electron</span> spectral measurements and the accuracy of density scale-length measurements are evaluated. 2D EPOCH PIC code simulations are found to be in agreement with measurements of the <span class="hlt">electron</span> energy spectra showing that laser filamentation in <span class="hlt">plasma</span> preformed by a prepulse is important with longer <span class="hlt">plasma</span> scale lengths (>8 μm). PMID:27176413</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://hdl.handle.net/2060/19880007150','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19880007150"><span id="translatedtitle">Relativistic electromagnetic waves in an <span class="hlt">electron</span>-ion <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>Chian, Abraham C.-L.; Kennel, Charles F.</p> <p>1987-01-01</p> <p>High power laser beams can drive <span class="hlt">plasma</span> particles to relativistic energies. An accurate description of strong waves requires the inclusion of ion dynamics in the analysis. The equations governing the propagation of relativistic electromagnetic waves in a cold <span class="hlt">electron</span>-ion <span class="hlt">plasma</span> can be reduced to two equations expressing conservation of energy-momentum of the system. The two conservation constants are functions of the <span class="hlt">plasma</span> stream velocity, the wave velocity, the wave amplitude, and the <span class="hlt">electron</span>-ion mass ratio. The dynamic parameter, expressing <span class="hlt">electron</span>-ion momentum conversation in the laboratory frame, can be regarded as an adjustable quantity, a suitable choice of which will yield self-consistent solutions when other <span class="hlt">plasma</span> parameters were specified. Circularly polarized electromagnetic waves and electrostatic <span class="hlt">plasma</span> waves are used as illustrations.</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://adsabs.harvard.edu/abs/1984GeoRL..11.1176W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1984GeoRL..11.1176W"><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://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wilhelm, K.; Bernstein, W.; Kellogg, P. J.; Whalen, B. A.</p> <p>1984-12-01</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://ntrs.nasa.gov/search.jsp?R=19850035938&hterms=tads&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dtads','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850035938&hterms=tads&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dtads"><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/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 metal–semiconductor 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/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/22490693','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22490693"><span id="translatedtitle">Annular vortex merging processes in non-neutral <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>Kaga, Chikato Ito, Kiyokazu; Higaki, Hiroyuki; Okamoto, Hiromi</p> <p>2015-06-29</p> <p>Non-neutral <span class="hlt">electron</span> <span class="hlt">plasmas</span> in a uniform magnetic field are investigated experimentally as a two dimensional (2D) fluid. Previously, it was reported that 2D phase space volume increases during a vortex merging process with viscosity. However, the measurement was restricted to a <span class="hlt">plasma</span> with a high density. Here, an alternative method is introduced to evaluate a similar process for a <span class="hlt">plasma</span> with a low density.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ApPhL.105c1908M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ApPhL.105c1908M"><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://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mirhosseini, Farid; Colpitts, Bruce</p> <p>2014-07-01</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/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/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; Fraiman, G. M.; Dodin, I. Y.; Fisch, N. J.</p> <p>2009-02-01</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<sup>-3</sup>. 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 < , Γ does not exceed Γ ~ aΥg, where a is the normalized laser field, and Υg is the group velocity Lorentz factor. Yet Υ ~ Γ 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://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://www.osti.gov/scitech/biblio/20216713','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20216713"><span id="translatedtitle">Accessibility 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>Carter, M. D.; Bigelow, T. S.; Batchelor, D. B.</p> <p>1999-09-20</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 design can also be applied near the <span class="hlt">electron</span> cyclotron frequency. In this paper, we investigate the 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>. (c) 1999 American Institute of Physics.</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://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://adsabs.harvard.edu/abs/2016NIMPA.829...83W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NIMPA.829...83W"><span id="translatedtitle"><span class="hlt">Electron</span> beam manipulation, injection and acceleration in <span class="hlt">plasma</span> wakefield accelerators by optically generated <span class="hlt">plasma</span> density spikes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wittig, Georg; Karger, Oliver S.; Knetsch, Alexander; Xi, Yunfeng; Deng, Aihua; Rosenzweig, James B.; Bruhwiler, David L.; Smith, Jonathan; Sheng, Zheng-Ming; Jaroszynski, Dino A.; Manahan, Grace G.; Hidding, Bernhard</p> <p>2016-09-01</p> <p>We discuss considerations regarding a novel and robust scheme for optically triggered <span class="hlt">electron</span> bunch generation in <span class="hlt">plasma</span> wakefield accelerators [1]. In this technique, a transversely propagating focused laser pulse ignites a quasi-stationary <span class="hlt">plasma</span> column before the arrival of the <span class="hlt">plasma</span> wake. This localized <span class="hlt">plasma</span> density enhancement or optical "<span class="hlt">plasma</span> torch" distorts the blowout during the arrival of the <span class="hlt">electron</span> drive bunch and modifies the <span class="hlt">electron</span> trajectories, resulting in controlled injection. By changing the gas density, and the laser pulse parameters such as beam waist and intensity, and by moving the focal point of the laser pulse, the shape of the <span class="hlt">plasma</span> torch, and therefore the generated trailing beam, can be tuned easily. The proposed method is much more flexible and faster in generating gas density transitions when compared to hydrodynamics-based methods, and it accommodates experimentalists needs as it is a purely optical process and straightforward to implement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016RScI...87kE401F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016RScI...87kE401F"><span id="translatedtitle"><span class="hlt">Plasma</span> characterization using ultraviolet Thomson scattering from ion-acoustic and <span class="hlt">electron</span> <span class="hlt">plasma</span> waves (invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Follett, R. K.; Delettrez, J. A.; Edgell, D. H.; Henchen, R. J.; Katz, J.; Myatt, J. F.; Froula, D. H.</p> <p>2016-11-01</p> <p>Collective Thomson scattering is a technique for measuring the <span class="hlt">plasma</span> conditions in laser-<span class="hlt">plasma</span> experiments. Simultaneous measurements of ion-acoustic and <span class="hlt">electron</span> <span class="hlt">plasma</span>-wave spectra were obtained using a 263.25-nm Thomson-scattering probe beam. A fully reflective collection system was used to record light scattered from <span class="hlt">electron</span> <span class="hlt">plasma</span> waves at <span class="hlt">electron</span> densities greater than 1021 cm-3, which produced scattering peaks near 200 nm. An accurate analysis of the experimental Thomson-scattering spectra required accounting for <span class="hlt">plasma</span> gradients, instrument sensitivity, optical effects, and background radiation. Practical techniques for including these effects when fitting Thomson-scattering spectra are presented and applied to the measured spectra to show the improvements in <span class="hlt">plasma</span> characterization.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21532014','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21532014"><span id="translatedtitle">Linear analysis of a rectangular waveguide cyclotron maser with a <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>Zhao Ding; Ding Yaogen; Wang Yong; Ruan Cunjun</p> <p>2010-11-15</p> <p>A linear theory for a rectangular waveguide cyclotron maser with a <span class="hlt">sheet</span> <span class="hlt">electron</span> beam is developed by using the Laplace transformation approach. This theory can be applied to any TE{sub mn} rectangular waveguide mode. The corresponding equations for the TM{sub mn} mode in the rectangular waveguide are also derived as a useful reference. Especially, the effect from the coupling between degenerate modes, which is induced by the nonideal rectangular waveguide walls, on the dispersion relation is considered in order to provide a more accurate model for the real devices. Through numerical calculations, the linear growth rate, launching loss, and spontaneous oscillations (caused by the absolute instability and backward wave oscillation) of this new structure can be analyzed in detail. It is worthwhile to point out that the operation at higher power levels of the rectangular waveguide <span class="hlt">sheet</span> beam system is possible.</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://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></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6044573','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6044573"><span id="translatedtitle">Adiabatic expansion of a strongly correlated pure <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>Dubin, D.H.E.; O'Neil, T.M.</p> <p>1986-02-17</p> <p>Adiabatic expansion is proposed as a method of increasing the degree of correlation of a magnetically confined pure <span class="hlt">electron</span> <span class="hlt">plasma</span>. Quantum mechanical effects and correlation effects make the physics of the expansion quite different from that for a classical ideal gas. The proposed expansion may be useful in a current experimental effort to cool a pure <span class="hlt">electron</span> <span class="hlt">plasma</span> to the liquid and solid (crystalline) states.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1986PhRvL..56..728D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1986PhRvL..56..728D"><span id="translatedtitle">Adiabatic expansion of a strongly correlated pure <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>Dubin, D. H. E.; Oneil, T. M.</p> <p>1986-02-01</p> <p>Adiabatic expansion is proposed as a method of increasing the degree of correlation of a magnetically confined pure <span class="hlt">electron</span> <span class="hlt">plasma</span>. Quantum mechanical effects and correlation effects make the physics of the expansion quite different from that for a classical ideal gas. The proposed expansion may be useful in a current experimental effort to cool a pure <span class="hlt">electron</span> <span class="hlt">plasma</span> to the liquid and solid (crystalline) states.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998PhDT.......144G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998PhDT.......144G"><span id="translatedtitle">Studies of cryogenic <span class="hlt">electron</span> <span class="hlt">plasmas</span> in magnetic mirror fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gopalan, Ramesh</p> <p></p> <p>This thesis considers the properties of pure <span class="hlt">electron</span> <span class="hlt">plasmas</span> in Penning traps which have an axially varying magnetic field. Our theory of the thermal equilibrium of such <span class="hlt">plasmas</span> in magnetic mirror fields indicates that their behavior may be characterized by the ratio of their temperature to their central density T/n. For cold, dense <span class="hlt">plasmas</span> the density along the <span class="hlt">plasma</span> axis scales linearly with the magnetic field, while for hot, tenuous <span class="hlt">plasmas</span>, at the opposite limit of the parameter range, the density is constant along the axis, similar to the behavior of a neutral <span class="hlt">plasma</span> in a magnetic mirror. We are able to conclude from this that the electrostatic potential varies along the field lines, in equilibrium. As the <span class="hlt">plasma</span> charge and potential distribution must be consistent with the grounded potential on the trap walls, the <span class="hlt">plasma</span> profile does not follow the geometry of the magnetic field lines; the <span class="hlt">plasma</span> radius in the high-field region is smaller than would be obtained by mapping the field lines from the radial edge of the low-field region. Another interesting feature of these mirror equilibria is that there are trapped populations of particles both in the low-field and high-field regions. Our experiments on the Cryogenic <span class="hlt">Electron</span> Trap have confirmed many of these theoretical results over a wide parameter range. We have been able to sample the volume charge density at various points on the axis. We have also measured the line-charge distribution of the <span class="hlt">plasma</span>. Both these experiments are in general agreement with our theory of the global thermal equilibrium in the mirror- field. A surprising observation has been the unexpectedly long- life of the m = 1 diocotron mode in these traps where the magnetic field varies by ~100% across its length. We report these observations, along with plausible explanations for them. The trap we have constructed is intended for the eventual study of very cold <span class="hlt">electron</span> <span class="hlt">plasmas</span> in strong magnetic fields, where the <span class="hlt">plasma</span> <span class="hlt">electrons</span> are</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19790030940&hterms=microwave+radiation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmicrowave%2Bradiation','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19790030940&hterms=microwave+radiation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmicrowave%2Bradiation"><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 of the NASA Lewis Bumpy Torus <span class="hlt">plasma</span> has been 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-ohm 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 20 billion to 800 billion per cu cm. A linear relation was observed between 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://adsabs.harvard.edu/abs/2015JPhCS.653a2159V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPhCS.653a2159V"><span id="translatedtitle">Movement of <span class="hlt">electron</span> when recombining in hydrogen <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>Vikhrev, V. V.</p> <p>2015-11-01</p> <p>An analytical model and the results of modeling are presented for movement of <span class="hlt">electrons</span> in recombining hydrogen <span class="hlt">plasma</span>. It is shown that in case of taking into account the magnetic moment and angular momentum as well as spin flip of <span class="hlt">electron</span> in magnetic field the <span class="hlt">electron</span> comes to the orbit with angular momentum ħ/2. If azimuthal and radial components of kinetic energy of <span class="hlt">electron</span> are equal then the full energy of such the orbits is 13.6 eV.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AGUFMSM31A2277W&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AGUFMSM31A2277W&link_type=ABSTRACT"><span id="translatedtitle">Dawn-dusk asymmetry in ion pitch-angle anisotropy in the near-Earth magnetosphere and 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>Wang, C.; Zaharia, S. G.; Lyons, L. R.; Angelopoulos, V.</p> <p>2012-12-01</p> <p>We found a strong dawn-dusk asymmetry in ion pitch-angle anisotropy from spatial distributions statistically determined using THEMIS observations. The asymmetry varies significantly with ion energies and is a result of different processes. The anisotropy of ions below several hundreds eV in the tail <span class="hlt">plasma</span> <span class="hlt">sheet</span> (beyond X = 10 Re) and the near-Earth magnetosphere (inside r = 10 Re) is dominantly negative (relatively higher particle fluxes near 0 and 180 degree pitch-angle) and is more strongly negative in the post-midnight sector than the pre-midnight sector. The negative anisotropy is likely caused by field-aligned ionosphere outflow and the post-midnight enhancement is correlated with stronger <span class="hlt">electron</span> precipitation energy fluxes that create stronger outflow. For ions between 1 to 10 keV in the near-Earth magnetosphere, anisotropy is found to be strongly positive (relatively higher fluxes near 90 degree pitch-angle) in the morning sector while near isotropic in the evening sector. Comparing the fluxes within the region of the positive anisotropy with other MLTs suggests that the positive anisotropy is caused by field-aligned ions not being able to drift as earthward as 90 degree ions. For ions of 10 keV and above, magnetic drift shell splitting results in strongly positive anisotropy on the dayside, while additional magnetopause shadowing causes strongly negative anisotropy in the post-midnight sector.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950048211&hterms=plasma+field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dplasma%2Bfield','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950048211&hterms=plasma+field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dplasma%2Bfield"><span id="translatedtitle"><span class="hlt">Plasma</span> flow and magnetic field characteristics near the midtail neutral <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>Nakamura, R.; Baker, D. N.; Fairfield, D. H.; Mitchell, D. G.; Mcpherron, R. L.; Hones, E. W., Jr.</p> <p>1994-01-01</p> <p>Using IMP 6, 7, and 8 magnetic field and <span class="hlt">plasma</span> data, we have determined statistical occurrance properties of bulk flow and magnetic field orientation near the midtail neutral <span class="hlt">sheet</span>. Characteristics of bulk <span class="hlt">plasma</span> flow and magnetic field significantly change according to the radial distance down the tail. High-speed flow events (v greater than 300 km/s) are essentially restricted to the region tailward of X = -2.5 R(sub E) and are predominatly sunward or tailward. The low-speed flows were nearly equally likely to be in any direction, with the occurace rate of dustward and sunward flow being larger than that of tailward and dawnward flow. Dustward flow occurrence is highest in the region Earthward of X = -2.5 R(sub E), while sunward flow occurrence is highest in the region tailward of X = -2.5 R(sub E). The significance of the dawn-to-dust flow in the near-Earth region obtained in our study supports the idea that there exists a very effective mechanism to accelerate ions in the dawn-to-dust direction and hence the relief of pressure buildup in the near-Earth region. During high-speed flow events the relationship between B(sub Z) polarity and <span class="hlt">plasma</span> flow direction is largely consistent with that expected from the magnetic reconnenection processes associted with substorms. There are also significant numbers of negative B9sub Z) events that are not associated with tailward flow. Mechanism other than substorm neutral line should therefore also taken into account to explain general B(sub Z) polarity in the midtail region.</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/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/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/2016PhPl...23h2310S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhPl...23h2310S"><span id="translatedtitle"><span class="hlt">Electron</span> acoustic solitary waves in a magnetized <span class="hlt">plasma</span> with nonthermal <span class="hlt">electrons</span> and an <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>Singh, S. V.; Devanandhan, S.; Lakhina, G. S.; Bharuthram, R.</p> <p>2016-08-01</p> <p>A theoretical investigation is carried out to study the obliquely propagating <span class="hlt">electron</span> acoustic solitary waves having nonthermal hot <span class="hlt">electrons</span>, cold and beam <span class="hlt">electrons</span>, and ions in a magnetized <span class="hlt">plasma</span>. We have employed reductive perturbation theory to derive the Korteweg-de-Vries-Zakharov-Kuznetsov (KdV-ZK) equation describing the nonlinear evolution of these waves. The two-dimensional plane wave solution of KdV-ZK equation is analyzed to study the effects of nonthermal and beam <span class="hlt">electrons</span> on the characteristics of the solitons. Theoretical results predict negative potential solitary structures. We emphasize that the inclusion of finite temperature effects reduces the soliton amplitudes and the width of the solitons increases by an increase in the obliquity of the wave propagation. The numerical analysis is presented for the parameters corresponding to the observations of "burst a" event by Viking satellite on the auroral field lines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16179470','PUBMED'); return false;" href="https://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="https://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.</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://www.osti.gov/scitech/biblio/6302014','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6302014"><span id="translatedtitle"><span class="hlt">Electron</span>-Hose Instability in an Annular <span class="hlt">Plasma</span> Sheath</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Whittum, David H.</p> <p>1999-07-08</p> <p>A relativistic <span class="hlt">electron</span> beam propagating through an annular <span class="hlt">plasma</span> sheath is subject to a transverse <span class="hlt">plasma-electron</span> coupled electrostatic instability. From the linearized fluid equations, the beam-sheath interaction is resolved into three coupled equations. The corresponding wakefield is computed and the asymptotic linear evolution is noted. For illustration, numerical examples are given for a <span class="hlt">plasma</span> accelerator employing such a sheath. While the coasting beam scalings are quite severe at low energy, single-bunch instability growth can in fact be reduced to nil, for a very high-gradient accelerator.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22072318','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22072318"><span id="translatedtitle">Pure <span class="hlt">electron</span> <span class="hlt">plasmas</span> confined for 90 ms in a stellarator without <span class="hlt">electron</span> sources or internal objects</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Brenner, P. W.; Sunn Pedersen, T.</p> <p>2012-05-15</p> <p>We report on the creation and up to 90 ms sustainment of pure <span class="hlt">electron</span> <span class="hlt">plasmas</span> confined in a stellarator without internal objects. Injection of positrons into such <span class="hlt">plasmas</span> is expected to lead to the creation of the first <span class="hlt">electron</span>-positron <span class="hlt">plasma</span> experiments. These newly created <span class="hlt">plasmas</span> will also allow a study of pure <span class="hlt">electron</span> <span class="hlt">plasmas</span> without the perturbing presence of internal objects. The <span class="hlt">plasmas</span> were created by thermionic emission of <span class="hlt">electrons</span> from a heated, biased filament that was retracted in 20 ms. The confinement of these transient <span class="hlt">plasmas</span> is different from that of steady state <span class="hlt">plasmas</span> with internal objects and emissive filaments, and is generally shorter, limited by ion buildup. The decay time is increased by lowering the neutral pressure, lowering the <span class="hlt">electron</span> <span class="hlt">plasma</span> temperature, or operating with neutrals with high ionization energies (helium). These findings are all consistent with ion accumulation being the cause for the shorter than expected confinement times. The magnetic field strength also moderately increases the decay times. The deleterious effect of ions is not expected to imply a similar deleterious effect when introducing positrons, but it implies that ion accumulation must be avoided also in an <span class="hlt">electron</span>-positron experiment.</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> </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://www.osti.gov/scitech/servlets/purl/5187695','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5187695"><span id="translatedtitle">Measurements of beat wave accelerated <span class="hlt">electrons</span> in a toroidal <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rogers, J.H. . Plasma Physics Lab.); Hwang, D.W. . Dept. of Applied Science Lawrence Livermore National Lab., CA )</p> <p>1992-06-01</p> <p><span class="hlt">Electrons</span> are accelerated by large amplitude <span class="hlt">electron</span> <span class="hlt">plasma</span> waves driven by counter-propagating microwaves with a difference frequency approximately equal to the <span class="hlt">electron</span> <span class="hlt">plasma</span> frequency. Energetic <span class="hlt">electrons</span> are observed only when the phase velocity of the wave is in the range 3v{sub e} < v{sub ph} < 7v{sub e} (v{sub ph} was varied 2v{sub e} < v{sub ph} < 10v{sub e}), where v{sub e} is the <span class="hlt">electron</span> thermal velocity, (kT{sub e}/m{sub e}){sup {1/2}}. As the phase velocity increases, fewer <span class="hlt">electrons</span> are accelerated to higher velocities. The measured current contained in these accelerated <span class="hlt">electrons</span> has the power dependence predicted by theory, but the magnitude is lower than predicted.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1980TepVT..18..897V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1980TepVT..18..897V"><span id="translatedtitle"><span class="hlt">Electron</span>-ion bremsstrahlung continuum emission in nonideal <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>Valuev, A. A.; Kurilenkov, Iu. K.</p> <p>1980-09-01</p> <p>The effect of the Coulomb nonidealness of a <span class="hlt">plasma</span> on bremsstrahlung emission (absorption) over a wide spectral range is analyzed using numerical data on <span class="hlt">electron</span> dynamics in nonideal fully ionized <span class="hlt">plasmas</span> with charged-particle densities of 10 to the 18th-20th/cu cm and a temperature of 10,000 K. The results are compared with calculations obtained through Kramers' formula and with values of the bremsstrahlung emission coefficient derived from experimental data on the radiation from dense <span class="hlt">plasmas</span>. These results point to the fact that relative 'bleaching' of nonideal <span class="hlt">plasmas</span> occur in the IR region of the spectrum.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1981HTemS..18..679V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1981HTemS..18..679V"><span id="translatedtitle"><span class="hlt">Electron</span>-ion bremsstrahlung continuum emission in nonideal <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>Valuev, A. A.; Kurilenkov, Iu. K.</p> <p>1981-03-01</p> <p>The effect of the Coulomb nonidealness of a <span class="hlt">plasma</span> on bremsstrahlung emission (absorption) over a wide spectral range is analyzed using numerical data on <span class="hlt">electron</span> dynamics in nonideal fully ionized <span class="hlt">plasmas</span> with charged-particle densities of 10 to the 18th-20th/cu cm and a temperature of 10,000 K. The results are compared with calculations obtained through Kramers' formula and with values of the bremsstrahlung emission coefficient derived from experimental data on the radiation from dense <span class="hlt">plasmas</span>. These results point to the fact that relative 'bleaching' of nonideal <span class="hlt">plasmas</span> occur in the IR region of the spectrum.</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://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://adsabs.harvard.edu/abs/2015APS..GECQR1002G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..GECQR1002G"><span id="translatedtitle">Hydrated <span class="hlt">Electrons</span> at the <span class="hlt">Plasma</span>-Water Interface</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Graves, David; Gopalakrishnan, Ranga; Kawamura, Emi; Lieberman, Michael</p> <p>2015-09-01</p> <p>When atmospheric pressure <span class="hlt">plasma</span> interacts with liquid water surfaces, complex processes involving both charged and neutral species generally occur but the details of the processes are not well understood. One <span class="hlt">plasma</span>-generated specie of considerable interest that can enter an adjacent liquid water phase is the <span class="hlt">electron</span>. Hydrated <span class="hlt">electrons</span> are well known to be important in radiation chemistry as initiating precursors for a variety of other reactive compounds. Recent experimental evidence for hydrated <span class="hlt">electrons</span> near the atmospheric pressure <span class="hlt">plasma</span>-water interface was reported by Rumbach et al.. We present results from a model of a dc argon <span class="hlt">plasma</span> coupled to an anodic adjacent water layer that aims to simulate this experiment. The coupled <span class="hlt">plasma</span>-electrolyte model illustrates the nature of the <span class="hlt">plasma</span>-water interface and reveals important information regarding the self-consistent electric fields on each side of the interface as well as time- and space-resolved rates of reaction of key reactive species. We suggest that the reducing chemistry that results from <span class="hlt">electron</span> hydration may be useful therapeutically in countering local excess oxidative stress. Supported by the Department of Energy, Office of Fusion Science <span class="hlt">Plasma</span> Science Center</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20515138','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20515138"><span id="translatedtitle">Control of <span class="hlt">electron</span> temperature and space potential gradients by superposition of thermionic <span class="hlt">electrons</span> on <span class="hlt">electron</span> cyclotron resonance <span class="hlt">plasmas</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Moon, Chanho; Kaneko, Toshiro; Tamura, Shuichi; Hatakeyama, Rikizo</p> <p>2010-05-01</p> <p>An <span class="hlt">electron</span> temperature gradient (ETG) is formed perpendicular to the magnetic field lines by superimposing low-temperature thermionic <span class="hlt">electrons</span> emitted from a tungsten hot plate upon high-temperature <span class="hlt">electrons</span> of an <span class="hlt">electron</span> cyclotron resonance <span class="hlt">plasma</span>, which pass through two different-shaped mesh grids. The radial profile of the <span class="hlt">plasma</span> space potential can be controlled independent of the ETG by changing the bias voltages of the hot plate.</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://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/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/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://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/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://adsabs.harvard.edu/abs/2016NatSR...629114L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatSR...629114L"><span id="translatedtitle">Unexpected <span class="hlt">electronic</span> structure of the alloyed and doped arsenene <span class="hlt">sheets</span>: First-Principles calculations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Ming-Yang; Huang, Yang; Chen, Qing-Yuan; Cao, Chao; He, Yao</p> <p>2016-07-01</p> <p>We study the equilibrium geometry and <span class="hlt">electronic</span> structure of alloyed and doped arsenene <span class="hlt">sheets</span> based on the density functional theory calculations. AsN, AsP and SbAs alloys possess indirect band gap and BiAs is direct band gap. Although AsP, SbAs and BiAs alloyed arsenene <span class="hlt">sheets</span> maintain the semiconducting character of pure arsenene, they have indirect-direct and semiconducting-metallic transitions by applying biaxial strain. We find that B- and N-doped arsenene render p-type semiconducting character, while C- and O-doped arsenene are metallic character. Especially, the C-doped arsenene is spin-polarization asymmetric and can be tuned into the bipolar spin-gapless semiconductor by the external electric field. Moreover, the doping concentration can effectively affect the magnetism of the C-doped system. Finally, we briefly study the chemical molecule adsorbed arsenene. Our results may be valuable for alloyed and doped arsenene <span class="hlt">sheets</span> applications in mechanical sensors and spintronic devices in the future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4931469','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4931469"><span id="translatedtitle">Unexpected <span class="hlt">electronic</span> structure of the alloyed and doped arsenene <span class="hlt">sheets</span>: First-Principles calculations</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Liu, Ming-Yang; Huang, Yang; Chen, Qing-Yuan; Cao, Chao; He, Yao</p> <p>2016-01-01</p> <p>We study the equilibrium geometry and <span class="hlt">electronic</span> structure of alloyed and doped arsenene <span class="hlt">sheets</span> based on the density functional theory calculations. AsN, AsP and SbAs alloys possess indirect band gap and BiAs is direct band gap. Although AsP, SbAs and BiAs alloyed arsenene <span class="hlt">sheets</span> maintain the semiconducting character of pure arsenene, they have indirect-direct and semiconducting-metallic transitions by applying biaxial strain. We find that B- and N-doped arsenene render p-type semiconducting character, while C- and O-doped arsenene are metallic character. Especially, the C-doped arsenene is spin-polarization asymmetric and can be tuned into the bipolar spin-gapless semiconductor by the external electric field. Moreover, the doping concentration can effectively affect the magnetism of the C-doped system. Finally, we briefly study the chemical molecule adsorbed arsenene. Our results may be valuable for alloyed and doped arsenene <span class="hlt">sheets</span> applications in mechanical sensors and spintronic devices in the future. PMID:27373712</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://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/489098','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/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://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> </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://www.osti.gov/scitech/biblio/21506911','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21506911"><span id="translatedtitle">Energetic <span class="hlt">Electron</span> Transport In An Inhomogeneous <span class="hlt">Plasma</span> Medium</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Das, Amita</p> <p>2010-11-23</p> <p>A review of the work carried out at IPR on energetic <span class="hlt">electron</span> transport through an inhomogeneous <span class="hlt">plasma</span> medium is presented in this article. A Generalized <span class="hlt">Electron</span> Magnetohydrodynamic (G-EMHD) fluid model has been developed and employed for such studies. Novel observations such as (i) the trapping of <span class="hlt">electron</span> current pulse structure in a high density <span class="hlt">plasma</span> region, (ii) the formation of sharp magnetic field shock structures at the inhomogeneous <span class="hlt">plasma</span> density layer (iii) and intense energy dissipation at the shock layer even in the collisionless limit are reported. The intense energy dissipation of the <span class="hlt">electron</span> current pulse at the shock layer provides a mechanism whereby highly energetic <span class="hlt">electrons</span> which are essentially collision-less can also successfully deposit their energy in a local region of the <span class="hlt">plasma</span>. This is specially attractive as it opens up the possibility of heating a localized region of an overdense <span class="hlt">plasma</span> (where lasers cannot penetrate) by highly energetic collision-less <span class="hlt">electrons</span>. A direct application of this mechanism to Fast Ignition (FT) experiments is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22093733','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22093733"><span id="translatedtitle">Revisiting <span class="hlt">plasma</span> hysteresis with an <span class="hlt">electronically</span> compensated Langmuir probe</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Srivastava, P. K.; Singh, S. K.; Awasthi, L. M.; Mattoo, S. K.</p> <p>2012-09-15</p> <p>The measurement of <span class="hlt">electron</span> temperature in <span class="hlt">plasma</span> by Langmuir probes, using ramped bias voltage, is seriously affected by the capacitive current of capacitance of the cable between the probe tip and data acquisition system. In earlier works a dummy cable was used to balance the capacitive currents. Under these conditions, the measured capacitive current was kept less than a few mA. Such probes are suitable for measurements in <span class="hlt">plasma</span> where measured ion saturation current is of the order of hundreds of mA. This paper reports that controlled balancing of capacitive current can be minimized to less than 20 {mu}A, allowing <span class="hlt">plasma</span> measurements to be done with ion saturation current of the order of hundreds of {mu}A. The <span class="hlt">electron</span> temperature measurement made by using probe compensation technique becomes independent of sweep frequency. A correction of {<=}45% is observed in measured <span class="hlt">electron</span> temperature values when compared with uncompensated probe. This also enhances accuracy in the measurement of fluctuation in <span class="hlt">electron</span> temperature as {delta}T{sub pk-pk} changes by {approx}30%. The developed technique with swept rate {<=}100 kHz is found accurate enough to measure both the <span class="hlt">electron</span> temperature and its fluctuating counterpart. This shows its usefulness in measuring accurately the temperature fluctuations because of <span class="hlt">electron</span> temperature gradient in large volume <span class="hlt">plasma</span> device <span class="hlt">plasma</span> with frequency ordering {<=}50 kHz.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23020373','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23020373"><span id="translatedtitle">Revisiting <span class="hlt">plasma</span> hysteresis with an <span class="hlt">electronically</span> compensated Langmuir probe.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Srivastava, P K; Singh, S K; Awasthi, L M; Mattoo, S K</p> <p>2012-09-01</p> <p>The measurement of <span class="hlt">electron</span> temperature in <span class="hlt">plasma</span> by Langmuir probes, using ramped bias voltage, is seriously affected by the capacitive current of capacitance of the cable between the probe tip and data acquisition system. In earlier works a dummy cable was used to balance the capacitive currents. Under these conditions, the measured capacitive current was kept less than a few mA. Such probes are suitable for measurements in <span class="hlt">plasma</span> where measured ion saturation current is of the order of hundreds of mA. This paper reports that controlled balancing of capacitive current can be minimized to less than 20 μA, allowing <span class="hlt">plasma</span> measurements to be done with ion saturation current of the order of hundreds of μA. The <span class="hlt">electron</span> temperature measurement made by using probe compensation technique becomes independent of sweep frequency. A correction of ≤45% is observed in measured <span class="hlt">electron</span> temperature values when compared with uncompensated probe. This also enhances accuracy in the measurement of fluctuation in <span class="hlt">electron</span> temperature as δT(pk-pk) changes by ~30%. The developed technique with swept rate ≤100 kHz is found accurate enough to measure both the <span class="hlt">electron</span> temperature and its fluctuating counterpart. This shows its usefulness in measuring accurately the temperature fluctuations because of <span class="hlt">electron</span> temperature gradient in large volume <span class="hlt">plasma</span> device <span class="hlt">plasma</span> with frequency ordering ≤50 kHz.</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://ntrs.nasa.gov/search.jsp?R=19820058707&hterms=Harp&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%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%3D70%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://adsabs.harvard.edu/abs/2016PhPl...23h3509G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhPl...23h3509G"><span id="translatedtitle">Modeling the effect of doping on the catalyst-assisted growth and field emission properties of <span class="hlt">plasma</span>-grown 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>Gupta, Neha; Sharma, Suresh C.; Sharma, Rinku</p> <p>2016-08-01</p> <p>A theoretical model describing the effect of doping on the <span class="hlt">plasma</span>-assisted catalytic growth of graphene <span class="hlt">sheet</span> has been developed. The model accounts the charging rate of the graphene <span class="hlt">sheet</span>, kinetics of all the <span class="hlt">plasma</span> species, including the doping species, and the growth rate of graphene nuclei and graphene <span class="hlt">sheet</span> due to surface diffusion, and accretion of ions on the catalyst nanoparticle. Using the model, it is observed that nitrogen and boron doping can strongly influence the growth and field emission properties of the graphene <span class="hlt">sheet</span>. The results of the present investigation indicate that nitrogen doping results in reduced thickness and shortened height of the graphene <span class="hlt">sheet</span>; however, boron doping increases the thickness and height of the graphene <span class="hlt">sheet</span>. The time evolutions of the charge on the graphene <span class="hlt">sheet</span> and hydrocarbon number density for nitrogen and boron doped graphene <span class="hlt">sheet</span> have also been examined. The field emission properties of the graphene <span class="hlt">sheet</span> have been proposed on the basis of the results obtained. It is concluded that nitrogen doped graphene <span class="hlt">sheet</span> exhibits better field emission characteristics as compared to undoped and boron doped graphene <span class="hlt">sheet</span>. The results of the present investigation are consistent with the existing experimental observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhPl...23e3504S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhPl...23e3504S"><span id="translatedtitle"><span class="hlt">Electron</span> temperature and density measurements of laser induced germanium <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>Shakeel, Hira; Arshad, Saboohi; Haq, S. U.; Nadeem, Ali</p> <p>2016-05-01</p> <p>The germanium <span class="hlt">plasma</span> produced by the fundamental harmonics (1064 nm) of Nd:YAG laser in single and double pulse configurations have been studied spectroscopically. The <span class="hlt">plasma</span> is characterized by measuring the <span class="hlt">electron</span> temperature using the Boltzmann plot method for neutral and ionized species and <span class="hlt">electron</span> number density as a function of laser irradiance, ambient pressure, and distance from the target surface. It is observed that the <span class="hlt">plasma</span> parameters have an increasing trend with laser irradiance (9-33 GW/cm2) and with ambient pressure (8-250 mbar). However, a decreasing trend is observed along the plume length up to 4.5 mm. The <span class="hlt">electron</span> temperature and <span class="hlt">electron</span> number density are also determined using a double pulse configuration, and their behavior at fixed energy ratio and different interpulse delays is discussed.</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 2–3 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/2016NIMPA.829...33W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NIMPA.829...33W"><span id="translatedtitle">Generation of attosecond <span class="hlt">electron</span> bunches in a laser-<span class="hlt">plasma</span> accelerator using a <span class="hlt">plasma</span> density upramp</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Weikum, M. K.; Li, F. Y.; Assmann, R. W.; Sheng, Z. M.; Jaroszynski, D.</p> <p>2016-09-01</p> <p>Attosecond <span class="hlt">electron</span> bunches and attosecond radiation pulses enable the study of ultrafast dynamics of matter in an unprecedented regime. In this paper, the suitability for the experimental realization of a novel scheme producing sub-femtosecond duration <span class="hlt">electron</span> bunches from laser-wakefield acceleration in <span class="hlt">plasma</span> with self-injection in a <span class="hlt">plasma</span> upramp profile has been investigated. While it has previously been predicted that this requires laser power above a few hundred terawatts typically, here we show that the scheme can be extended with reduced driving laser powers down to tens of terawatts, generating accelerated <span class="hlt">electron</span> pulses with minimum length of around 166 attoseconds and picocoulombs charge. Using particle-in-cell simulations and theoretical models, the evolution of the accelerated <span class="hlt">electron</span> bunch within the <span class="hlt">plasma</span> as well as simple scalings of the bunch properties with initial laser and <span class="hlt">plasma</span> parameters are presented.</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://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://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/cgi-bin/nph-data_query?bibcode=2014cosp...40E.893F&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014cosp...40E.893F&link_type=ABSTRACT"><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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPhD...48A5202P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPhD...48A5202P"><span id="translatedtitle">The influence of magnetic field on <span class="hlt">electron</span> beam generated <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>Petrov, G. M.; Boris, D. R.; Lock, E. H.; Petrova, Tz B.; Fernsler, R. F.; Walton, S. G.</p> <p>2015-06-01</p> <p>Magnetically confined argon <span class="hlt">plasma</span> in a long cylindrical tube driven by an <span class="hlt">electron</span> beam is studied experimentally and theoretically. Langmuir probes are used to measure the <span class="hlt">electron</span> energy distribution function, <span class="hlt">electron</span> density and temperature in <span class="hlt">plasmas</span> generated by 2 keV, 10 mA <span class="hlt">electron</span> beams in a 25 mTorr argon background for magnetic field strengths of up to 200 Gauss. The experimental results agree with simulations done using a spatially averaged Boltzmann model adapted to treat an <span class="hlt">electron</span> beam generated <span class="hlt">plasma</span> immersed in a constant magnetic field. The confining effect of the magnetic field is studied theoretically using fluid and kinetic approaches. The fluid approach leads to two regimes of operation: weakly and strongly magnetized. The former is similar to the magnetic field-free case, while in the latter the ambipolar diffusion coefficient and <span class="hlt">electron</span> density depend quadratically on the magnetic field strength. Finally, a more rigorous kinetic treatment, which accounts for the impact of the magnetic field over the whole distribution of <span class="hlt">electrons</span>, is used for accurate description of the <span class="hlt">plasma</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20120007917&hterms=energetic&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Denergetic','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20120007917&hterms=energetic&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Denergetic"><span id="translatedtitle">Energetic O+ and H+ Ions in the <span class="hlt">Plasma</span> <span class="hlt">Sheet</span>: Implications for the Transport of Ionospheric Ions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ohtani, S.; Nose, M.; Christon, S. P.; Lui, A. T.</p> <p>2011-01-01</p> <p>The present study statistically examines the characteristics of energetic ions in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> using the Geotail/Energetic Particle and Ion Composition data. An emphasis is placed on the O+ ions, and the characteristics of the H+ ions are used as references. The following is a summary of the results. (1) The average O+ energy is lower during solar maximum and higher during solar minimum. A similar tendency is also found for the average H+ energy, but only for geomagnetically active times; (2) The O+ -to -H+ ratios of number and energy densities are several times higher during solar maximum than during solar minimum; (3) The average H+ and O+ energies and the O+ -to -H+ ratios of number and energy densities all increase with geomagnetic activity. The differences among different solar phases not only persist but also increase with increasing geomagnetic activity; (4) Whereas the average H+ energy increases toward Earth, the average O+ energy decreases toward Earth. The average energy increases toward dusk for both the H+ and O+ ions; (5) The O+ -to -H+ ratios of number and energy densities increase toward Earth during all solar phases, but most clearly during solar maximum. These results suggest that the solar illumination enhances the ionospheric outflow more effectively with increasing geomagnetic activity and that a significant portion of the O+ ions is transported directly from the ionosphere to the near ]Earth region rather than through the distant tail.</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://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://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://www.osti.gov/scitech/servlets/purl/9100','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/9100"><span id="translatedtitle">Self-effect in expanding <span class="hlt">electron</span> beam <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Garcia, M</p> <p>1999-05-07</p> <p>An analytical model of <span class="hlt">plasma</span> flow from a metal plate hit by an intense, pulsed, <span class="hlt">electron</span> beam aims to bridge the gap between radiation-hydrodynamics simulations and experiments, and to quantify the self-effect of the <span class="hlt">electron</span> beam penetrating the flow. Does the flow disrupt the tight focus of the initial <span class="hlt">electron</span> bunch, or later pulses in a train? This work aims to model the spatial distribution of <span class="hlt">plasma</span> speed, density, degree of ionization, and magnetization to inquire. The initial solid density, several eV <span class="hlt">plasma</span> expands to 1 cm and 10{sup {minus}4} relative density by 2 {micro}s, beyond which numerical simulations are imprecise. Yet, a Faraday cup detector at the ETA-II facility is at 25 cm from the target and observes the flow after 50 {micro}s. The model helps bridge this gap. The expansion of the target <span class="hlt">plasma</span> into vacuum is so rapid that the ionized portion of the flow departs from local thermodynamic equilibrium. When the temperature (in eV) in a parcel of fluid drops below V{sub i} x [(2{gamma} - 2)/(5{gamma} + 17)], where V{sub i} is the ionization potential of the target metal (7.8 eV for tantalum), and {gamma} is the ratio of specific heats (5/3 for atoms), then the fractional ionization and <span class="hlt">electron</span> temperature in that parcel remain fixed during subsequent expansion. The freezing temperature as defined here is V{sub i}/19. The balance between the self-pinching force and the space charge repulsion of an <span class="hlt">electron</span> beam changes on penetrating a flow: (i) the target <span class="hlt">plasma</span> cancels the space-charge field, (ii) internal eddy currents arise to counter the magnetization of relativistic <span class="hlt">electrons</span>, and (iii) <span class="hlt">electron</span> beam heating alters the flow magnetization by changing the <span class="hlt">plasma</span> density gradient and the magnitude of the conductivity.</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> </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://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://adsabs.harvard.edu/abs/2011PhPl...18l2107X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhPl...18l2107X"><span id="translatedtitle">Decays of <span class="hlt">electron</span> Bernstein waves near <span class="hlt">plasma</span> edge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xiang, Nong; Cary, John R.</p> <p>2011-12-01</p> <p>Nonlinear wave-wave couplings near the upper hybrid resonance are studied via particle-in-cell simulations. It is found that the decay of an <span class="hlt">electron</span> Bernstein wave (EBW) depends on the ratio of the incident frequency and <span class="hlt">electron</span> cyclotron frequency. For ratios less than two, parametric decay into a lower hybrid wave (or an ion Bernstein wave) and EBWs at a lower frequency is observed. For ratios larger than two, the daughter waves could be an <span class="hlt">electron</span> cyclotron quasi-mode and another EBW or an ion wave and EBW. For sufficiently high incident power, the former process may dominate. Because of the <span class="hlt">electron</span> cyclotron quasi-mode, <span class="hlt">electrons</span> can be strongly heated by nonlinear Landau damping. As a result, the bulk of the incident power can be absorbed near <span class="hlt">plasma</span> edge at high power. The increase in number of decay channels with frequency implies that the allowable power into the <span class="hlt">plasma</span> must decrease with frequency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11308588','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11308588"><span id="translatedtitle">Anomalous <span class="hlt">electron</span> mobility in a coaxial Hall discharge <span class="hlt">plasma</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Meezan, N B; Hargus, W A; Cappelli, M A</p> <p>2001-02-01</p> <p>A comprehensive analysis of measurements supporting the presence of anomalous cross-field <span class="hlt">electron</span> mobility in Hall <span class="hlt">plasma</span> accelerators is presented. Nonintrusive laser-induced fluorescence measurements of neutral xenon and ionized xenon velocities, and various electrostatic probe diagnostic measurements are used to locally determine the effective <span class="hlt">electron</span> Hall parameter inside the accelerator channel. These values are then compared to the classical (collision-driven) Hall parameters expected for a quiescent magnetized <span class="hlt">plasma</span>. The results indicate that in the vicinity of the anode, where there are fewer <span class="hlt">plasma</span> instabilities, the <span class="hlt">electron</span>-transport mechanism is likely elastic collisions with the background neutral xenon. However, we find that in the vicinity of the discharge channel exit, where the magnetic field is the strongest and where there are intense fluctuations in the <span class="hlt">plasma</span> properties, the inferred Hall parameter departs from the classical value, and is close to the Bohm value of (omega(ce)tau)(eff) approximately 16. These results are used to support a simple model for the Hall parameter that is based on the scalar addition of the <span class="hlt">electron</span> collision frequencies (elastic collision induced plus fluctuation induced), as proposed by Boeuf and Garrigues [J. Appl. Phys. 84, 3541 (1998)]. The results also draw attention to the possible role of fluctuations in enhancing <span class="hlt">electron</span> transport in regions where the <span class="hlt">electrons</span> are highly magnetized.</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://adsabs.harvard.edu/abs/2014MNRAS.439..924B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014MNRAS.439..924B"><span id="translatedtitle">Transparency of an instantaneously created <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>Bégué, D.; Vereshchagin, G. V.</p> <p>2014-03-01</p> <p>The problem of the expansion of a relativistic <span class="hlt">plasma</span> generated when a large amount of energy is released in a small volume has been considered by many authors. We use the analytical solution of Bisnovatyi-Kogan and Murzina for the spherically symmetric relativistic expansion. The light curves and the spectra from transparency of an <span class="hlt">electron</span>-positron-photon <span class="hlt">plasma</span> are obtained. We compare our results with the work of Goodman.</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/22489833','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22489833"><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://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shukla, Chandrasekhar; Das, Amita; Patel, Kartik</p> <p>2015-11-15</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/k{sub s} of the inhomogeneous <span class="hlt">plasma</span> is less than the typical <span class="hlt">plasma</span> skin depth (c/ω{sub 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://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://ntrs.nasa.gov/search.jsp?R=19920029434&hterms=wave+saturation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dwave%2Bsaturation','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920029434&hterms=wave+saturation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dwave%2Bsaturation"><span id="translatedtitle">Simulation of the nonlinear evolution of <span class="hlt">electron</span> <span class="hlt">plasma</span> waves</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.; Cairns, I. H.</p> <p>1991-01-01</p> <p>Electrostatic waves driven by an <span class="hlt">electron</span> beam in an ambient magnetized <span class="hlt">plasma</span> were studied using a quasi-1D PIC simulation of <span class="hlt">electron</span> <span class="hlt">plasma</span> waves (i.e., Langmuir waves). The results disclose the presence of a process for moving wave energy from frequencies and wavenumbers predicted by linear theory to the Langmuir-like frequencies during saturation of the instability. A decay process for producing backward propagating Langmuir-like waves, along with low-frequency waves, is observed. The simulation results, however, indicate that the backscattering process is not the conventional Langmuir wave decay. Electrostatic waves near multiples of the <span class="hlt">electron</span> <span class="hlt">plasma</span> frequency are generated by wave-wave coupling during the nonlinear stage of the simulations, confirming the suggestion of Klimas (1983).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JaJAP..55gLG08Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JaJAP..55gLG08Y"><span id="translatedtitle">Characteristics of surface sterilization using <span class="hlt">electron</span> cyclotron resonance <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>Yonesu, Akira; Hara, Kazufumi; Nishikawa, Tatsuya; Hayashi, Nobuya</p> <p>2016-07-01</p> <p>The characteristics of surface sterilization using <span class="hlt">electron</span> cyclotron resonance (ECR) <span class="hlt">plasma</span> were investigated. High-energy <span class="hlt">electrons</span> and oxygen radicals were observed in the ECR zone using electric probe and optical emission spectroscopic methods. A biological indicator (BI), Geobacillus stearothermophilus, containing 1 × 106 spores was sterilized in 120 s by exposure to oxygen discharges while maintaining a temperature of approximately 55 °C at the BI installation position. Oxygen radicals and high-energy <span class="hlt">electrons</span> were found to be the sterilizing species in the ECR region. It was demonstrated that the ECR <span class="hlt">plasma</span> could be produced in narrow tubes with an inner diameter of 5 mm. Moreover, sterilization tests confirmed that the spores present inside the narrow tube were successfully inactivated by ECR <span class="hlt">plasma</span> irradiation.</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/2014JETP..118..521V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JETP..118..521V"><span id="translatedtitle">Scattering of <span class="hlt">electrons</span> by vacuum fluctuations of <span class="hlt">plasma</span> waves</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Veklenko, B. A.; Afanas'ev, V. P.; Lubenchenko, A. V.</p> <p>2014-04-01</p> <p>Interaction between a probe <span class="hlt">electron</span> beam and longitudinal electromagnetic oscillations of the Fermi <span class="hlt">plasma</span> in metals (plasmons) is investigated by the methods of quantum electrodynamics. The quantum description of plasmons allows one to construct a consistent theory of the scattering process and point out the applicability limits of the existing semiclassical theories. The quantum description of plasmons leads to the concept of electromagnetic vacuum of longitudinal waves, which is the subject of the present study. The vacuum of longitudinal waves significantly deforms the shape of <span class="hlt">plasma</span> dielectric permittivity, thus leading to the broadening of Langmuir peaks of scattered <span class="hlt">electrons</span>, which has so far resisted theoretical analysis. The presence of the electromagnetic vacuum of longitudinal <span class="hlt">plasma</span> waves has a considerable effect on the integral scattering probability of <span class="hlt">electrons</span> by plasmons.</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/22494334','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22494334"><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://www.osti.gov/scitech">SciTech Connect</a></p> <p>Siutsou, I. A.; Aksenov, A. G.</p> <p>2015-12-17</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('https://www.ncbi.nlm.nih.gov/pubmed/17931024','PUBMED'); return false;" href="https://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="https://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 Schrödinger 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22488668','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22488668"><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://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shrivastava, G. Ahirwar, G.; Shrivastava, J.</p> <p>2015-07-31</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 β 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 (T{sub i}/T{sub e}), 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://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, 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 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</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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016NJPh...18i3023E&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016NJPh...18i3023E&link_type=ABSTRACT"><span id="translatedtitle">Effect of bremsstrahlung radiation emission on fast <span class="hlt">electrons</span> in <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>Embréus, O.; Stahl, A.; Fülöp, T.</p> <p>2016-09-01</p> <p>Bremsstrahlung radiation emission is an important energy loss mechanism for energetic <span class="hlt">electrons</span> in <span class="hlt">plasmas</span>. In this paper we investigate the effect of spontaneous bremsstrahlung emission on the momentum‑space structure of the <span class="hlt">electron</span> distribution, fully accounting for the emission of finite‑energy photons by modeling the bremsstrahlung interactions with a Boltzmann collision operator. We find that <span class="hlt">electrons</span> accelerated by electric fields can reach significantly higher energies than predicted by the commonly used radiative stopping‑power model. Furthermore, we show that the emission of soft photons can contribute significantly to the dynamics of <span class="hlt">electrons</span> with an anisotropic distribution by causing pitch‑angle scattering at a rate that increases with 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_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/2016NJPh...18i3023E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NJPh...18i3023E"><span id="translatedtitle">Effect of bremsstrahlung radiation emission on fast <span class="hlt">electrons</span> in <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>Embréus, O.; Stahl, A.; Fülöp, T.</p> <p>2016-09-01</p> <p>Bremsstrahlung radiation emission is an important energy loss mechanism for energetic <span class="hlt">electrons</span> in <span class="hlt">plasmas</span>. In this paper we investigate the effect of spontaneous bremsstrahlung emission on the momentum-space structure of the <span class="hlt">electron</span> distribution, fully accounting for the emission of finite-energy photons by modeling the bremsstrahlung interactions with a Boltzmann collision operator. We find that <span class="hlt">electrons</span> accelerated by electric fields can reach significantly higher energies than predicted by the commonly used radiative stopping-power model. Furthermore, we show that the emission of soft photons can contribute significantly to the dynamics of <span class="hlt">electrons</span> with an anisotropic distribution by causing pitch-angle scattering at a rate that increases with energy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10185615','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10185615"><span id="translatedtitle">Magnetic insulation of secondary <span class="hlt">electrons</span> in <span class="hlt">plasma</span> source ion implantation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rej, D.J.; Wood, B.P.; Faehl, R.J.; Fleischmann, H.H.</p> <p>1993-09-01</p> <p>The uncontrolled loss of accelerated secondary <span class="hlt">electrons</span> in <span class="hlt">plasma</span> source ion implantation (PSII) can significantly reduce system efficiency and poses a potential x-ray hazard. This loss might be reduced by a magnetic field applied near the workpiece. The concept of magnetically-insulated PSII is proposed, in which secondary <span class="hlt">electrons</span> are trapped to form a virtual cathode layer near the workpiece surface where the local electric field is essentially eliminated. Subsequent <span class="hlt">electrons</span> that are emitted can then be reabsorbed by the workpiece. Estimates of anomalous <span class="hlt">electron</span> transport from microinstabilities are made. Insight into the process is gained with multi-dimensional particle-in-cell simulations.</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://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://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/21316501','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21316501"><span id="translatedtitle">Dynamical Casimir effect for TE and TM modes in a resonant cavity bisected by a <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>Naylor, W.; Matsuki, S.; Kido, Y.; Nishimura, T.</p> <p>2009-10-15</p> <p>Parametric photon creation via the dynamical Casimir effect (DCE) is evaluated numerically, in a three-dimensional rectangular resonant cavity bisected by a semiconductor diaphragm (SD), which is irradiated by a pulsed laser with frequency of GHz order. The aim of this paper is to determine some of the optimum conditions required to detect DCE photons relevant to an experimental detection system. We expand upon the thin <span class="hlt">plasma</span> <span class="hlt">sheet</span> model [M. Crocce et al., Phys. Rev. A 70, 033811 (2004)] to estimate the number of photons for both transverse electric (TE) and transverse magnetic (TM) modes at any given SD position. Numerical calculations are performed considering up to 51 intermode couplings by varying the SD location, driving period and laser power without any perturbations. It is found that the number of photons created for TE modes strongly depends on SD position, where the strongest enhancement occurs at the midpoint (not near the cavity wall); while TM modes have weak dependence on SD position. Another important finding is the fact that significant photon production for TM{sub 111} modes still takes place at the midpoint even for a low-laser power of 0.01 {mu}J/pulse, although the number of TE{sub 111} photons decreases almost proportionately with laser power. We also find a relatively wide tuning range for both TE and TM modes that is correlated with the frequency variation in the instantaneous mode functions caused by the interaction between the cavity photons and conduction <span class="hlt">electrons</span> in the SD excited by a pulsed laser.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001PhDT........14Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001PhDT........14Q"><span id="translatedtitle"><span class="hlt">Electron</span> series resonance <span class="hlt">plasma</span> discharges: Unmagnetized and magnetized</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qiu, Weiguang</p> <p>2001-08-01</p> <p>This thesis explores high frequency <span class="hlt">electron</span> series resonance in unmagnetized and magnetized bounded <span class="hlt">plasmas</span>. Special interest is focused on low temperature <span class="hlt">plasmas</span> in planar systems as such are useful for material processing and fusion devices. Chapter 1, Chapter 2 and Chapter 3 describe simulation studies of unmagnetized <span class="hlt">electron</span> series resonance (ESR) sustained discharges with comparisons to theory and experiment. These <span class="hlt">plasmas</span> have many desirable characteristics. The input resistance is small and the drive voltage and current are in phase. The drive voltage is small (˜Te) and the time average <span class="hlt">plasma</span> potential is low (˜10Te). A strong kinetic phase space bunching process is shown to provide <span class="hlt">electrons</span> of sufficient energy for ionization, which allows discharge operation at low neutral pressure and low <span class="hlt">electron</span> temperatures. At low pressure, the ion flux to the wall has a narrow angular spread about the normal and the ion bombarding energy distribution has a sharp peak at the <span class="hlt">plasma</span> potential. Scaling laws at fixed pressure nr∝w3RF ,s¯∝w -1RF are shown to hold when RF frequency is varied smoothly ("chirping") demonstrating continuous density control. Research on magnetized <span class="hlt">electron</span> series resonance (MESR) discharges is described in Chapter 4, Chapter 5 and Chapter 6. The resonant frequency is derived from cold <span class="hlt">plasma</span> theory and shows two resonant modes. Simulations verify these modes to be the natural oscillatory frequencies of weakly magnetized <span class="hlt">plasmas</span> in a planar <span class="hlt">plasma</span> diode. A global model is established for magnetized resonant discharges. The interrelations among the <span class="hlt">plasma</span> parameters and the drive terms are formulated for both resonant modes. The initiation of a MESR discharge and its steady state properties are discussed and compared to the unmagnetized case. Weak lock-on of MESR frequency to the drive frequency is observed in simulation. Similar V - I characteristics as those in ESR are found both in theory and in simulation. Different from the ESR</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22490168','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22490168"><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://www.osti.gov/scitech">SciTech Connect</a></p> <p>Martín-Solís, J. R.; Loarte, A.; Lehnen, M.</p> <p>2015-09-15</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://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>Martín-Solís, 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://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014PlST...16..995Z&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014PlST...16..995Z&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Electron</span> Acoustic Solitary Waves in Magnetized Quantum <span class="hlt">Plasma</span> with Relativistic Degenerated <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>Zhu, Zhenni; Wu, Zhengwei; Li, Chunhua; Yang, Weihong</p> <p>2014-11-01</p> <p>A model for the nonlinear properties of obliquely propagating <span class="hlt">electron</span> acoustic solitary waves in a two-<span class="hlt">electron</span> populated relativistically quantum magnetized <span class="hlt">plasma</span> is presented. By using the standard reductive perturbation technique, the Zakharov-Kuznetsov (ZK) equation is derived and this equation gives the solitary wave solution. It is observed that the relativistic effects, the ratio of the cold to hot <span class="hlt">electron</span> unperturbed number density and the magnetic field normalized by <span class="hlt">electron</span> cyclotron frequency significantly influence the solitary structures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21347213','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21347213"><span id="translatedtitle">Continuous gas discharge <span class="hlt">plasma</span> with 200 K <span class="hlt">electron</span> temperature</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Dickson, Shannon; Robertson, Scott</p> <p>2010-03-15</p> <p>A very cold and collisional hot-filament discharge <span class="hlt">plasma</span> is created in a vacuum chamber with an inner wall cooled by liquid nitrogen. The inner chamber (16.5 cm diameterx30 cm) has two negatively biased tungsten filaments for <span class="hlt">plasma</span> generation and a Langmuir probe on axis for diagnostic measurements. With the wall at 140 K, 0.5-16 mA filament emission, and 1.6 mTorr carbon monoxide as the working gas, probe data give <span class="hlt">electron</span> temperatures of 17-28 meV (197-325 K) with corresponding densities of 10{sup 8}-10{sup 9} cm{sup -3}. With He, Ar, H{sub 2}, and N{sub 2} at 140 K, the <span class="hlt">electron</span> temperatures are >500 K. The lower <span class="hlt">electron</span> temperature with CO is attributed to the asymmetric CO molecule having a larger cross section for <span class="hlt">electron</span> excitation of rotational modes as a consequence of its dipole moment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM51D..03F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM51D..03F"><span id="translatedtitle">Cluster observations of the <span class="hlt">plasma</span> <span class="hlt">sheet</span> at very high latitudes: The in situ signature of a transpolar arc</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fear, R. C.; Milan, S. E.; Maggiolo, R.</p> <p>2013-12-01</p> <p>Transpolar arcs are auroral features which extend into the polar cap, which is the dim region poleward of the main auroral oval. Several case and statistical studies have shown that they are formed by the closure of lobe magnetic flux by magnetotail reconnection, and that the transpolar arc forms at the footprints of the newly-closed field lines which are embedded within the open flux of the polar cap. Therefore, when transpolar arcs occur, the magnetotail should contain closed magnetic field lines even at high latitudes (but in a localised sector), embedded within the open lobe flux. We present in situ observations of this phenomenon, taken by the Cluster spacecraft on 15th September 2005. Cluster was located at high latitudes in the southern hemisphere lobe (far from the typical location of the <span class="hlt">plasma</span> <span class="hlt">sheet</span>), and a transpolar arc was observed by the FUV cameras on the IMAGE satellite. An initial analysis reveals that Cluster periodically observed <span class="hlt">plasma</span> similar to a typical <span class="hlt">plasma</span> <span class="hlt">sheet</span> distribution, but at much higher latitudes - indicative of closed flux embedded within the high latitude lobe. Each time that this <span class="hlt">plasma</span> distribution was observed, the footprint of the spacecraft mapped to the transpolar arc (significantly poleward of the main auroral oval). These observations are consistent with closed flux being trapped in the magnetotail and embedded within the lobe, and provide further evidence for transpolar arcs being formed by magnetotail reconnection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4979162','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4979162"><span id="translatedtitle">Easy-to-Use Preservation and Application of Platelet-Rich <span class="hlt">Plasma</span> in Combination Wound Therapy With a Gelatin <span class="hlt">Sheet</span> and Freeze-Dried Platelet-Rich <span class="hlt">Plasma</span>: A Case Report</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kakudo, Natsuko; Ogura, Tsunekata; Hara, Tomoya; Matsui, Makoto; Yamamoto, Masaya; Tabata, Yasuhiko; Kusumoto, Kenji</p> <p>2016-01-01</p> <p>Objective: Platelet-rich <span class="hlt">plasma</span> is blood <span class="hlt">plasma</span> enriched with platelets and contains various growth factors. Two major issues remain to be resolved in the use of platelet-rich <span class="hlt">plasma</span>: the short biological activity after application, and the need to prepare platelet-rich <span class="hlt">plasma</span> at each application instance. To overcome these problems, we developed a drug delivery system using gelatin hydrogel and preserved the excess platelet-rich <span class="hlt">plasma</span> as freeze-dried platelet-rich <span class="hlt">plasma</span>. We then applied combination treatment with a gelatin <span class="hlt">sheet</span> and platelet-rich <span class="hlt">plasma</span> at the first instance and freeze-dried platelet-rich <span class="hlt">plasma</span> at the second instance in the treatment of a nonhealing wound. Methods: A 68-year-old woman had suffered open fracture of her right tibia 2 years prior, and a split-thickness skin graft had been applied to repair the skin defect on the right tibia. She had multiple relapse of ulcers, and the present ulcer had not healed for 2 months. After debridement, 2 mL of activated platelet-rich <span class="hlt">plasma</span> was applied to the ulcer, and the gelatin <span class="hlt">sheet</span> was laid to impregnate with the platelet-rich <span class="hlt">plasma</span>, after which the <span class="hlt">sheet</span> was covered with a polyurethane film. Thirty-three days after the first platelet-rich <span class="hlt">plasma</span> application, the freeze-dried platelet-rich <span class="hlt">plasma</span> was reconstituted and 2 mL of the reconstituted platelet-rich <span class="hlt">plasma</span> was applied with a gelatin <span class="hlt">sheet</span>. Results: At 14 days after the freeze-dried platelet-rich <span class="hlt">plasma</span> application, the wound was mostly epithelized, with the rest of the wound covered with granulation tissue. Conclusions: These findings suggest that combination wound therapy with a gelatin <span class="hlt">sheet</span> and freeze-dried platelet-rich <span class="hlt">plasma</span> is a promising method for resolving issues with conventional platelet-rich <span class="hlt">plasma</span> treatment. PMID:27555889</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhyS...91i5601M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhyS...91i5601M"><span id="translatedtitle">Photon and <span class="hlt">electron</span> Landau damping in quantum <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>Mendonça, J. T.; Serbeto, A.</p> <p>2016-09-01</p> <p>Using a quantum kinetic description, we establish a general expression for the dispersion relation of <span class="hlt">electron</span> <span class="hlt">plasma</span> waves in the presence of an arbitrary spectrum of electromagnetic waves. This includes both <span class="hlt">electron</span> and photon Landau damping. The quantum kinetic description allows us to compare directly these two distinct processes, and to show that they are indeed quite similar. The present work also extends previous results on photon Landau damping onto the quantum domain.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1981JGR....86.8199G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1981JGR....86.8199G"><span id="translatedtitle">Determination of Jupiter's <span class="hlt">electron</span> density profile from <span class="hlt">plasma</span> wave observations</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.; Scarf, F. L.; Kurth, W. S.; Shaw, R. R.; Poynter, R. L.</p> <p>1981-09-01</p> <p>The <span class="hlt">electron</span> density measurements obtained in the Jovian magnetosphere from the <span class="hlt">plasma</span> wave instruments on the Voyager 1 and 2 spacecraft are summarized. Three basic techniques for determining the <span class="hlt">electron</span> density are discussed. They are (1) local measurements from the low-frequency cutoff of continuum radiation, (2) local measurements from the frequency of upper hybrid resonance emissions, and (3) integral measurements from the dispersion of whistlers. The limitations and advantages of each technique are reviewed.</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> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JGRA..113.9318P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JGRA..113.9318P"><span id="translatedtitle">Equatorial <span class="hlt">plasma</span> bubbles with enhanced ion and <span class="hlt">electron</span> temperatures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Park, Jaeheung; Min, Kyoung Wook; Kim, Vitaly P.; Kil, Hyosub; Su, Shin-Yi; Chao, Chi Kuang; Lee, Jae-Jin</p> <p>2008-09-01</p> <p>While the ion and <span class="hlt">electron</span> temperatures inside equatorial <span class="hlt">plasma</span> bubbles (EPBs) are normally lower than those in an ambient <span class="hlt">plasma</span>, bubbles with enhanced temperatures (BETs) are found occasionally in the topside ionosphere. Here we report the characteristics of BETs identified from observations of the first Republic of China Satellite (ROCSAT-1), the first Korea Multi-purpose Satellite (KOMPSAT-1), and the Defense Meteorological Satellite Program (DMSP) F15 during the solar maximum period between 2000 and 2001. The oxygen ion fraction inside the BETs, which was no lower than that of the ambient ionosphere, was similar to the case of ordinary low-temperature EPBs. These observations indicate that the BETs and low-temperature EPBs detected on the topside were produced by the upward drift of low-density <span class="hlt">plasma</span> from lower altitudes. The feature that distinguishes BETs from normal EPBs is the occurrence of an unusually fast poleward field-aligned <span class="hlt">plasma</span> flow relative to the ambient <span class="hlt">plasma</span>. The BETs occurred preferentially around geomagnetic latitudes of 10° in the summer hemisphere, where the ambient ion and <span class="hlt">electron</span> temperatures are lower than those in the conjugate winter hemisphere. The occurrence of BETs did not show any notable dependence on geomagnetic activities. The characteristics of the BETs suggest that the BETs were produced by adiabatic <span class="hlt">plasma</span> heating associated with a fast poleward oxygen ion transport along magnetic flux tubes.</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/21266655','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21266655"><span id="translatedtitle">Diagnostic techniques for measuring suprathermal <span class="hlt">electron</span> dynamics in <span class="hlt">plasmas</span> (invited)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Coda, S.</p> <p>2008-10-15</p> <p><span class="hlt">Plasmas</span>, both in the laboratory and in space, are often not in thermodynamic equilibrium, and the <span class="hlt">plasma</span> <span class="hlt">electron</span> distribution function is accordingly non-Maxwellian. Suprathermal <span class="hlt">electron</span> tails can be generated by external drives, such as rf waves and electric fields, or internal ones, such as instabilities and magnetic reconnection. The variety and importance of the phenomena in which suprathermal <span class="hlt">electrons</span> play a significant role explains an enduring interest in diagnostic techniques to investigate their properties and dynamics. X-ray bremsstrahlung emission has been studied in hot magnetized <span class="hlt">plasmas</span> for well over two decades, flanked progressively by <span class="hlt">electron</span>-cyclotron emission in geometries favoring the high-energy end of the distribution function (high-field-side, vertical, oblique emission), by <span class="hlt">electron</span>-cyclotron absorption, by spectroscopic techniques, and at lower temperatures, by Langmuir probes and electrostatic analyzers. Continuous progress in detector technology and in measurement and analysis techniques, increasingly sophisticated layouts (multichannel and tomographic systems, imaging geometries), and highly controlled suprathermal generation methods (e.g., perturbative rf modulation) have all been brought to bear in recent years on an increasingly detailed, although far from complete, understanding of suprathermal <span class="hlt">electron</span> dynamics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004PhPl...11.2709S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004PhPl...11.2709S"><span id="translatedtitle">Effects of <span class="hlt">plasma</span> composition on backscatter, hot <span class="hlt">electron</span> production, and propagation in underdense <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>Stevenson, R. M.; Suter, L. J.; Oades, K.; Kruer, W.; Slark, G. E.; Fournier, K. B.; Meezan, N.; Kauffman, R.; Miller, M.; Glenzer, S.; Niemann, C.; Grun, J.; Davis, J.; Back, C.; Thomas, B.</p> <p>2004-05-01</p> <p>A series of underdense laser <span class="hlt">plasma</span> interaction experiments performed on the Helen laser [M. J. Norman et al., Appl. Opt. 41, 3497 (2002)] at the Atomic Weapons Establishment (AWE), U.K., using 2ω light have uncovered a strong dependence of laser backscatter and hot <span class="hlt">electron</span> production on <span class="hlt">plasma</span> composition. Using low-Z materials, we find a behavior familiar from previous 3ω work, the interchange of stimulated Raman scattering for Brillouin scattering as we change from gases that have high ion wave damping (e.g., C5H12) to gases with low ion wave damping (e.g., CO2). However, as Z is increased, we find that Brillouin scattering drops while Raman scattering remains low. For gases with Z greater than 18, it is possible to have long scalelength, underdense <span class="hlt">plasmas</span> with both low Brillouin and Raman backscatter losses. Complementary measurements of hot <span class="hlt">electron</span> production show efficient production of hot <span class="hlt">electrons</span> in C5H12 <span class="hlt">plasmas</span> approaching 0.25ncr, but changing the <span class="hlt">plasma</span> composition can greatly suppress the hot <span class="hlt">electron</span> production, even near 0.25ncr. Additional experiments indicate that by adding small amounts of high Z dopant, significant changes to the backscatter and hot <span class="hlt">electron</span> production in C5H12 targets may be produced.</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://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/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://adsabs.harvard.edu/abs/2016PhPl...23i2704S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhPl...23i2704S"><span id="translatedtitle">Two-<span class="hlt">electron</span> atoms under spatially compressed Debye <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>Saha, Jayanta K.; Bhattacharyya, S.; Mukherjee, T. K.</p> <p>2016-09-01</p> <p>Rayleigh-Ritz variational method has been employed to estimate precise energy-eigenvalues of spherically compressed two-<span class="hlt">electron</span> atoms ( Z =1 -10 ) embedded in Debye <span class="hlt">plasma</span> with a view to modelling atom under dense <span class="hlt">plasma</span> environment. The trial wave function is expanded in terms of explicitly correlated Hylleraas-type basis set satisfying Dirichlet's boundary condition. The combined effect of decrease in the size of spatial confinement domain and increase in Debye screening parameter pushes the system towards gradual destabilization and subsequent ionization or complete fragmentation of the system. Present results are in reasonable agreement with other results existing in literature. Within finite domain, the thermodynamic pressure experienced by the ions due to the <span class="hlt">plasma</span> <span class="hlt">electrons</span> is also estimated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008JPhCS.129a2007K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008JPhCS.129a2007K&link_type=ABSTRACT"><span id="translatedtitle">Electrostatic screening in nanostructures with multicomponent <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>Kovalev, V. M.; Chaplik, A. V.</p> <p>2008-10-01</p> <p>Screening of the Coulumb interaction accounting for the Friedel oscillations in the structures with multicomponent low-dimensional <span class="hlt">electron</span> <span class="hlt">plasma</span> is considered. Calculations are made for nanotubes, double quantum wells (DQW) and superlattices. The binding energy of a donor in DQW is found as a function of the subbands occupation numbers.</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/2005EPJD...35..279B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005EPJD...35..279B"><span id="translatedtitle"><span class="hlt">Electron</span>-driven processes in high-pressure <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>Becker, K. H.; Masoud, N. M.; Martus, K. E.; Schoenbach, K. H.</p> <p>2005-08-01</p> <p>This review article summarizes results from selected recent studies of collisional and radiative processes initiated and driven by low-energy <span class="hlt">electron</span> interactions with atoms and molecules in high-pressure <span class="hlt">plasmas</span>. A special emphasis of the article is on spectroscopic studies of <span class="hlt">plasmas</span> used as sources for non-coherent vacuum ultraviolet radiation such as rare excimer emissions and atomic and molecular emissions from <span class="hlt">plasmas</span> in admixtures of rare gases and the molecular gases H{2} and N{2}. An attempt is made to correlate the various observed emission features and their dependence on the <span class="hlt">plasma</span> operating parameters (pressure, power, gas mixture, mode of excitation, etc.) to the underlying microscopic atomic and molecular processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004APS..DPPFP1123B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004APS..DPPFP1123B&link_type=ABSTRACT"><span id="translatedtitle">New <span class="hlt">Electron</span> Temperature Diagnostic for 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>Boivin, Robert; Loch, Stuart</p> <p>2004-11-01</p> <p>A new line ratio diagnostic design to measure <span class="hlt">electron</span> temperature in <span class="hlt">plasma</span> is presented. Unlike previous diagnostics, this new technique features emission lines originating from levels with different principal quantum numbers. A significant advantage of this approach is that the line ratio varies considerably with temperature in the 1 to 20 eV range. Another advantage is that both transitions are optically thin even for <span class="hlt">plasma</span> density up to 1 E 14 cm-3. The drawbacks are: a large difference in the line intensities and the significant difference in wavelength. The event of high sensitivity CCD camera combine with precise calibration can to a large extent minimize these latest two issues. The diagnostic is tested on the ASTRAL (Auburn Steady sTate Research fAciLity) helicon <span class="hlt">plasma</span> source. ASTRAL is a 2.3 m long helicon source designed to investigate basic <span class="hlt">plasma</span> and space <span class="hlt">plasma</span> processes. The device produces <span class="hlt">plasmas</span> with the following typical parameters ne = 1 E9 to 1 E13 cm-3, Te = 2 to 20 eV and Ti = 0.03 to 0.3 eV. A series of 8 large coils produce an axial magnetic field up to 1.2 kGauss. Operating pressure varies from 0.1 to 100 mTorr. A water cooled fractional helix antenna is used to introduce RF power up to 2 kwatt through a standard matching circuit. The line ratio temperatures are measured by means of a 0.33 m McPherson Criss-Cross Scanning monochromator instrumented with a SPH5 Apogee CCD camera. The line ratio temperatures are compared to <span class="hlt">electron</span> temperatures measured by a rf compensated Langmuir Probe. To validate the diagnostic, a new collisional radiative model that makes use of the latest excitation cross-section values is presented. The model is also used to predict the potential range of this new diagnostic both in terms of <span class="hlt">electron</span> temperature and <span class="hlt">plasma</span> density.</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('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4557361','PMC'); return false;" href="https://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 2.5±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://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="https://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://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://ntrs.nasa.gov/search.jsp?R=19940033865&hterms=screening&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dscreening','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19940033865&hterms=screening&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dscreening"><span id="translatedtitle"><span class="hlt">Plasma</span>-screening effects on the <span class="hlt">electron</span>-impact excitation of hydrogenic ions 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>Jung, Young-Dae</p> <p>1993-01-01</p> <p><span class="hlt">Plasma</span>-screening effects are investigated on <span class="hlt">electron</span>-impact excitation of hydrogenic ions in dense <span class="hlt">plasmas</span>. Scaled cross sections Z(exp 4) sigma for 1s yields 2s and 1s yields 2p are obtained for a Debye-Hueckel model of the screened Coulomb interaction. Ground and excited bound wave functions are modified in the screened Coulomb potential (Debye-Hueckel model) using the Ritz variation method. The resulting atomic wave functions and their eigenenergies agree well with the numerical and high-order perturbation theory calculations for the interesting domain of the Debye length not less than 10. The Born approximation is used to describe the continuum states of the projectile <span class="hlt">electron</span>. <span class="hlt">Plasma</span> screening effects on the atomic <span class="hlt">electrons</span> cannot be neglected in the high-density cases. Including these effects, the cross sections are appreciably increased for 1s yields 2s transitions and decreased for 1s yields 2p transitions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22496223','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22496223"><span id="translatedtitle"><span class="hlt">Electron</span> beam generated whistler emissions in a laboratory <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Van Compernolle, B. Pribyl, P.; Gekelman, W.; An, X.; Bortnik, J.; Thorne, R. M.</p> <p>2015-12-10</p> <p>Naturally occurring whistler mode emissions in the magnetosphere, are important since they are responsible for the acceleration of outer radiation belt <span class="hlt">electrons</span> to relativistic energies and also for the scattering loss of these <span class="hlt">electrons</span> into the atmosphere. Recently, we reported on the first laboratory experiment where whistler waves exhibiting fast frequency chirping have been artificially produced [1]. A beam of energetic <span class="hlt">electrons</span> is launched into a cold <span class="hlt">plasma</span> and excites both chirping whistler waves and broadband waves. Here we extend our previous analysis by comparing the properties of the broadband waves with linear theory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhPl...23i3116L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhPl...23i3116L"><span id="translatedtitle">Explosion of relativistic <span class="hlt">electron</span> vortices in laser <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>Lezhnin, K. V.; Kamenets, F. F.; Esirkepov, T. Zh.; Bulanov, S. V.; Gu, Y. J.; Weber, S.; Korn, G.</p> <p>2016-09-01</p> <p>The interaction of high intensity laser radiation with an underdense <span class="hlt">plasma</span> may lead to the formation of <span class="hlt">electron</span> vortices. Though being quasistationary on the <span class="hlt">electron</span> timescales, these structures tend to expand on a proton timescale due to Coulomb repulsion of ions. Using a simple analytical model of a stationary vortex as an initial condition, 2D PIC simulations are performed. A number of effects are observed such as vortex boundary field intensification, multistream instabilities at the vortex boundary, and bending of the vortex boundary with the subsequent transformation into smaller <span class="hlt">electron</span> vortices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...827L...7M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...827L...7M"><span id="translatedtitle">Turbulence and Proton–<span class="hlt">Electron</span> Heating in Kinetic <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>Matthaeus, William H.; Parashar, Tulasi N.; Wan, Minping; Wu, P.</p> <p>2016-08-01</p> <p>Analysis of particle-in-cell simulations of kinetic <span class="hlt">plasma</span> turbulence reveals a connection between the strength of cascade, the total heating rate, and the partitioning of dissipated energy into proton heating and <span class="hlt">electron</span> heating. A von Karman scaling of the cascade rate explains the total heating across several families of simulations. The proton to <span class="hlt">electron</span> heating ratio increases in proportion to total heating. We argue that the ratio of gyroperiod to nonlinear turnover time at the ion kinetic scales controls the ratio of proton and <span class="hlt">electron</span> heating. The proposed scaling is consistent with simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AIPC.1689h0014V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AIPC.1689h0014V"><span id="translatedtitle"><span class="hlt">Electron</span> beam generated whistler emissions 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>Van Compernolle, B.; An, X.; Bortnik, J.; Thorne, R. M.; Pribyl, P.; Gekelman, W.</p> <p>2015-12-01</p> <p>Naturally occurring whistler mode emissions in the magnetosphere, are important since they are responsible for the acceleration of outer radiation belt <span class="hlt">electrons</span> to relativistic energies and also for the scattering loss of these <span class="hlt">electrons</span> into the atmosphere. Recently, we reported on the first laboratory experiment where whistler waves exhibiting fast frequency chirping have been artificially produced [1]. A beam of energetic <span class="hlt">electrons</span> is launched into a cold <span class="hlt">plasma</span> and excites both chirping whistler waves and broadband waves. Here we extend our previous analysis by comparing the properties of the broadband waves with linear theory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930062681&hterms=hydrogen+energy+distribution&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dhydrogen%2Benergy%2Bdistribution','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930062681&hterms=hydrogen+energy+distribution&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dhydrogen%2Benergy%2Bdistribution"><span id="translatedtitle">Determining <span class="hlt">electron</span> temperature and density in a hydrogen microwave <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>Scott, Carl D.; Farhat, Samir; Gicquel, Alix; Hassouni, Khaled; Lefebvre, Michel</p> <p>1993-01-01</p> <p>A three-temperature thermo-chemical model is developed for analyzing the chemical composition and energy states of a hydrogen microwave <span class="hlt">plasma</span> used for studying diamond deposition. The chemical and energy exchange rate coefficients are determined from cross section data, assuming Maxwellian velocity distributions for <span class="hlt">electrons</span>. The model is reduced to a zero-dimensional problem to solve for the <span class="hlt">electron</span> temperature and ion mole fraction, using measured vibrational and rotational temperatures. The calculations indicate that the <span class="hlt">electron</span> temperature may be determined to within a few percent error even though the uncertainty in dissociation fraction is many times larger.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JPlPh..82b9005M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JPlPh..82b9005M&link_type=ABSTRACT"><span id="translatedtitle">Relativistic thermal <span class="hlt">electron</span> scale instabilities in sheared flow <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>Miller, Evan D.; Rogers, Barrett N.</p> <p>2016-04-01</p> <p>> The linear dispersion relation obeyed by finite-temperature, non-magnetized, relativistic two-fluid <span class="hlt">plasmas</span> is presented, in the special case of a discontinuous bulk velocity profile and parallel wave vectors. It is found that such flows become universally unstable at the collisionless <span class="hlt">electron</span> skin-depth scale. Further analyses are performed in the limits of either free-streaming ions or ultra-hot <span class="hlt">plasmas</span>. In these limits, the system is highly unstable in the parameter regimes associated with either the <span class="hlt">electron</span> scale Kelvin-Helmholtz instability (ESKHI) or the relativistic <span class="hlt">electron</span> scale sheared flow instability (RESI) recently highlighted by Gruzinov. Coupling between these modes provides further instability throughout the remaining parameter space, provided both shear flow and temperature are finite. An explicit parameter space bound on the highly unstable region is found.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhyA..451..525M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhyA..451..525M"><span id="translatedtitle">Nonextensive statistical mechanics approach to <span class="hlt">electron</span> trapping in degenerate <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>Mebrouk, Khireddine; Gougam, Leila Ait; Tribeche, Mouloud</p> <p>2016-06-01</p> <p>The <span class="hlt">electron</span> trapping in a weakly nondegenerate <span class="hlt">plasma</span> is reformulated and re-examined by incorporating the nonextensive entropy prescription. Using the q-deformed Fermi-Dirac distribution function including the quantum as well as the nonextensive statistical effects, we derive a new generalized <span class="hlt">electron</span> density with a new contribution proportional to the <span class="hlt">electron</span> temperature T, which may dominate the usual thermal correction (∼T2) at very low temperatures. To make the physics behind the effect of this new contribution more transparent, we analyze the modifications arising in the propagation of ion-acoustic solitary waves. Interestingly, we find that due to the nonextensive correction, our <span class="hlt">plasma</span> model allows the possibility of existence of quantum ion-acoustic solitons with velocity higher than the Fermi ion-sound velocity. Moreover, as the nonextensive parameter q increases, the critical temperature Tc beyond which coexistence of compressive and rarefactive solitons sets in, is shifted towards higher values.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12689298','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12689298"><span id="translatedtitle">Positron creation and annihilation in tokamak <span class="hlt">plasmas</span> with runaway <span class="hlt">electrons</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Helander, P; Ward, D J</p> <p>2003-04-01</p> <p>It is shown that <span class="hlt">electron</span>-positron pair production is expected to occur in post-disruption <span class="hlt">plasmas</span> in large tokamaks, including JET and JT-60U, where up to about 10(14) positrons may be created in collisions between multi-MeV runaway <span class="hlt">electrons</span> and thermal particles. If the loop voltage is large enough, they are accelerated and form a beam of long-lived runaway positrons in the direction opposite to that of the <span class="hlt">electrons</span>; if the loop voltage is smaller, the positrons have a lifetime of a few hundred ms, in which they are slowed down to energies comparable to that of the cool ( less, similar 10 eV) background <span class="hlt">plasma</span> before being annihilated.</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://www.osti.gov/scitech/biblio/21194989','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21194989"><span id="translatedtitle">Feedback control of <span class="hlt">plasma</span> <span class="hlt">electron</span> density and ion energy in an inductively coupled <span class="hlt">plasma</span> etcher</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lin Chaung; Leou, K.-C.; Huang, H.-M.; Hsieh, C.-H.</p> <p>2009-01-15</p> <p>Here the authors report the development of a fuzzy logic based feedback control of the <span class="hlt">plasma</span> <span class="hlt">electron</span> density and ion energy for high density <span class="hlt">plasma</span> etch process. The <span class="hlt">plasma</span> <span class="hlt">electron</span> density was measured using their recently developed transmission line microstrip microwave interferometer mounted on the chamber wall, and the rf voltage was measured by a commercial impedance meter connected to the wafer stage. The actuators were two 13.56 MHz rf power generators which provided the inductively coupled <span class="hlt">plasma</span> power and bias power, respectively. The control system adopted the fuzzy logic control algorithm to reduce frequent actuator action resulting from measurement noise. The experimental results show that the first wafer effect can be eliminated using closed-loop control for both poly-Si and HfO{sub 2} etching. In particular, for the HfO2 etch, the controlled variables in this work were much more effective than the previous one where ion current was controlled, instead of the <span class="hlt">electron</span> density. However, the pressure disturbance effect cannot be reduced using <span class="hlt">plasma</span> <span class="hlt">electron</span> density feedback.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20020043373&hterms=galileo&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dgalileo','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20020043373&hterms=galileo&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dgalileo"><span id="translatedtitle"><span class="hlt">Electron</span> Densities Near Io from Galileo <span class="hlt">Plasma</span> Wave Observations</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.; Persoon, A. M.; Kurth, W. S.; Roux, A.; Bolton, S. J.</p> <p>2001-01-01</p> <p>This paper presents an overview of <span class="hlt">electron</span> densities obtained near Io from the Galileo <span class="hlt">plasma</span> wave instrument during the first four flybys of Io. These flybys were Io, which was a downstream wake pass that occurred on December 7, 1995; I24, which was an upstream pass that occurred on October 11, 1999; I25, which was a south polar pass that occurred on November 26, 1999; and I27, which was an upstream pass that occurred on February 22, 2000. Two methods were used to measure the <span class="hlt">electron</span> density. The first was based on the frequency of upper hybrid resonance emissions, and the second was based on the low-frequency cutoff of electromagnetic radiation at the <span class="hlt">electron</span> <span class="hlt">plasma</span> frequency. For three of the flybys, Io, I25, and I27, large density enhancements were observed near the closest approach to Io. The peak <span class="hlt">electron</span> densities ranged from 2.1 to 6.8 x 10(exp 4) per cubic centimeters. These densities are consistent with previous radio occultation measurements of Io's ionosphere. No density enhancement was observed during the I24 flyby, most likely because the spacecraft trajectory passed too far upstream to penetrate Io's ionosphere. During two of the flybys, I25 and I27, abrupt step-like changes were observed at the outer boundaries of the region of enhanced <span class="hlt">electron</span> density. Comparisons with magnetic field models and energetic particle measurements show that the abrupt density steps occur as the spacecraft penetrated the boundary of the Io flux tube, with the region of high <span class="hlt">plasma</span> density on the inside of the flux tube. Most likely the enhanced <span class="hlt">electron</span> density within the Io flux tube is associated with magnetic field lines that are frozen to Io by the high conductivity of Io's atmosphere, thereby enhancing the escape of <span class="hlt">plasma</span> along the magnetic field lines that pass through Io's ionosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26565471','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26565471"><span id="translatedtitle">Active <span class="hlt">Plasma</span> Lensing for Relativistic Laser-<span class="hlt">Plasma</span>-Accelerated <span class="hlt">Electron</span> Beams.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>van Tilborg, J; Steinke, S; Geddes, C G R; Matlis, N H; Shaw, B H; Gonsalves, A J; Huijts, J V; Nakamura, K; Daniels, J; Schroeder, C B; Benedetti, C; Esarey, E; Bulanov, S S; Bobrova, N A; Sasorov, P V; Leemans, W P</p> <p>2015-10-30</p> <p>Compact, tunable, radially symmetric focusing of <span class="hlt">electrons</span> is critical to laser-<span class="hlt">plasma</span> accelerator (LPA) applications. Experiments are presented demonstrating the use of a discharge-capillary active <span class="hlt">plasma</span> lens to focus 100-MeV-level LPA beams. The lens can provide tunable field gradients in excess of 3000 T/m, enabling cm-scale focal lengths for GeV-level beam energies and allowing LPA-based <span class="hlt">electron</span> beams and light sources to maintain their compact footprint. For a range of lens strengths, excellent agreement with simulation was obtained. PMID:26565471</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvL.115r4802V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvL.115r4802V"><span id="translatedtitle">Active <span class="hlt">Plasma</span> Lensing for Relativistic Laser-<span class="hlt">Plasma</span>-Accelerated <span class="hlt">Electron</span> Beams</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van Tilborg, J.; Steinke, S.; Geddes, C. G. R.; Matlis, N. H.; Shaw, B. H.; Gonsalves, A. J.; Huijts, J. V.; Nakamura, K.; Daniels, J.; Schroeder, C. B.; Benedetti, C.; Esarey, E.; Bulanov, S. S.; Bobrova, N. A.; Sasorov, P. V.; Leemans, W. P.</p> <p>2015-10-01</p> <p>Compact, tunable, radially symmetric focusing of <span class="hlt">electrons</span> is critical to laser-<span class="hlt">plasma</span> accelerator (LPA) applications. Experiments are presented demonstrating the use of a discharge-capillary active <span class="hlt">plasma</span> lens to focus 100-MeV-level LPA beams. The lens can provide tunable field gradients in excess of 3000 T /m , enabling cm-scale focal lengths for GeV-level beam energies and allowing LPA-based <span class="hlt">electron</span> beams and light sources to maintain their compact footprint. For a range of lens strengths, excellent agreement with simulation was obtained.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015PPCF...57i5006N&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015PPCF...57i5006N&link_type=ABSTRACT"><span id="translatedtitle">Kinetic modelling of runaway <span class="hlt">electron</span> avalanches in tokamak <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>Nilsson, E.; Decker, J.; Peysson, Y.; Granetz, R. S.; Saint-Laurent, F.; Vlainic, M.</p> <p>2015-09-01</p> <p>Runaway <span class="hlt">electrons</span> can be generated in tokamak <span class="hlt">plasmas</span> if the accelerating force from the toroidal electric field exceeds the collisional drag force owing to Coulomb collisions with the background <span class="hlt">plasma</span>. In ITER, disruptions are expected to generate runaway <span class="hlt">electrons</span> mainly through knock-on collisions (Hender et al 2007 Nucl. Fusion 47 S128-202), where enough momentum can be transferred from existing runaways to slow <span class="hlt">electrons</span> to transport the latter beyond a critical momentum, setting off an avalanche of runaway <span class="hlt">electrons</span>. Since knock-on runaways are usually scattered off with a significant perpendicular component of the momentum with respect to the local magnetic field direction, these particles are highly magnetized. Consequently, the momentum dynamics require a full 3D kinetic description, since these <span class="hlt">electrons</span> are highly sensitive to the magnetic non-uniformity of a toroidal configuration. For this purpose, a bounce-averaged knock-on source term is derived. The generation of runaway <span class="hlt">electrons</span> from the combined effect of Dreicer mechanism and knock-on collision process is studied with the code LUKE, a solver of the 3D linearized bounce-averaged relativistic <span class="hlt">electron</span> Fokker-Planck equation (Decker and Peysson 2004 DKE: a fast numerical solver for the 3D drift kinetic equation Report EUR-CEA-FC-1736, Euratom-CEA), through the calculation of the response of the <span class="hlt">electron</span> distribution function to a constant parallel electric field. The model, which has been successfully benchmarked against the standard Dreicer runaway theory now describes the runaway generation by knock-on collisions as proposed by Rosenbluth (Rosenbluth and Putvinski 1997 Nucl. Fusion 37 1355-62). This paper shows that the avalanche effect can be important even in non-disruptive scenarios. Runaway formation through knock-on collisions is found to be strongly reduced when taking place off the magnetic axis, since trapped <span class="hlt">electrons</span> can not contribute to the runaway <span class="hlt">electron</span> population. Finally, the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009JGRA..114.7213W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009JGRA..114.7213W"><span id="translatedtitle">Anisotropy of the Taylor scale and the correlation scale in <span class="hlt">plasma</span> <span class="hlt">sheet</span> and solar wind magnetic field fluctuations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Weygand, James M.; Matthaeus, W. H.; Dasso, S.; Kivelson, M. G.; Kistler, L. M.; Mouikis, C.</p> <p>2009-07-01</p> <p>Magnetic field data from nine spacecraft in the magnetospheric <span class="hlt">plasma</span> <span class="hlt">sheet</span> and the solar wind are employed to determine the correlation scale and the magnetic Taylor microscale from simultaneous multiple-point measurements for multiple intervals with a range of mean magnetic field directions. We have determined that in the solar wind the Taylor scale is independent of direction relative to the mean magnetic field, but the correlation scale along the mean magnetic field (2.7 × 106 ± 0.2 × 106 km) is longer than along the perpendicular direction (1.5 × 106 ± 0.1 × 106 km). Within the <span class="hlt">plasma</span> <span class="hlt">sheet</span> we found that the correlation scale varies from 16,400 ± 1000 km along the mean magnetic field direction to 9200 ± 600 km in the perpendicular direction. The Taylor scale is also longer parallel to the magnetic field (2900 ± 100 km) than perpendicular to it (1100 ± 100 km). In the solar wind the ratio of the parallel correlation scale to the perpendicular correlation scale is 2.62 ± 0.79; in the <span class="hlt">plasma</span> <span class="hlt">sheet</span> the ratio is 1.78 ± 0.16, which indicates that the turbulence in both regions is anisotropic. The correlation and Taylor scales may be used to estimate effective magnetic Reynolds numbers separately for each angular channel. Reynolds numbers were found to be approximately independent of the angle relative to the mean magnetic field. These results may be useful in magnetohydrodynamic modeling of the solar wind and the magnetosphere and can contribute to our understanding of solar and galactic cosmic ray diffusion in the heliosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22490931','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22490931"><span id="translatedtitle">Arbitrary amplitude slow <span class="hlt">electron</span>-acoustic solitons in three-<span class="hlt">electron</span> temperature 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.; Singh, S. V.; Lakhina, G. S.</p> <p>2015-06-15</p> <p>We examine the characteristics of large amplitude slow <span class="hlt">electron</span>-acoustic solitons supported in a four-component unmagnetised <span class="hlt">plasma</span> composed of cool, warm, hot <span class="hlt">electrons</span>, and cool ions. The inertia and pressure for all the species in this <span class="hlt">plasma</span> system are retained by assuming that they are adiabatic fluids. Our findings reveal that both positive and negative potential slow <span class="hlt">electron</span>-acoustic solitons are supported in the four-component <span class="hlt">plasma</span> system. The polarity switch of the slow <span class="hlt">electron</span>-acoustic solitons is determined by the number densities of the cool and warm <span class="hlt">electrons</span>. Negative potential solitons, which are limited by the cool and warm <span class="hlt">electron</span> number densities becoming unreal and the occurrence of negative potential double layers, are found for low values of the cool <span class="hlt">electron</span> density, while the positive potential solitons occurring for large values of the cool <span class="hlt">electron</span> density are only limited by positive potential double layers. Both the lower and upper Mach numbers for the slow <span class="hlt">electron</span>-acoustic solitons are computed and discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhPl...23f2302M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhPl...23f2302M"><span id="translatedtitle">Arbitrary amplitude fast <span class="hlt">electron</span>-acoustic solitons in three-<span class="hlt">electron</span> component 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>Mbuli, L. N.; Maharaj, S. K.; Bharuthram, R.; Singh, S. V.; Lakhina, G. S.</p> <p>2016-06-01</p> <p>We examine the characteristics of fast <span class="hlt">electron</span>-acoustic solitons in a four-component unmagnetised <span class="hlt">plasma</span> model consisting of cool, warm, and hot <span class="hlt">electrons</span>, and cool ions. We retain the inertia and pressure for all the <span class="hlt">plasma</span> species by assuming adiabatic fluid behaviour for all the species. By using the Sagdeev pseudo-potential technique, the allowable Mach number ranges for fast <span class="hlt">electron</span>-acoustic solitary waves are explored and discussed. It is found that the cool and warm <span class="hlt">electron</span> number densities determine the polarity switch of the fast <span class="hlt">electron</span>-acoustic solitons which are limited by either the occurrence of fast <span class="hlt">electron</span>-acoustic double layers or warm and hot <span class="hlt">electron</span> number density becoming unreal. For the first time in the study of solitons, we report on the coexistence of fast <span class="hlt">electron</span>-acoustic solitons, in addition to the regular fast <span class="hlt">electron</span>-acoustic solitons and double layers in our multi-species <span class="hlt">plasma</span> model. Our results are applied to the generation of broadband electrostatic noise in the dayside auroral region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2225011','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2225011"><span id="translatedtitle"><span class="hlt">ELECTRON</span> MICROSCOPY OF <span class="hlt">PLASMA</span>-CELL TUMORS OF THE MOUSE</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Parsons, D. F.; Darden, E. B.; Lindsley, D. L.; Pratt, Guthrie T.</p> <p>1961-01-01</p> <p>An <span class="hlt">electron</span> microscope study was made of a series of transplanted MPC-1 <span class="hlt">plasma</span>-cell tumors carried by BALB/c mice. Large numbers of particles similar in morphology to virus particles were present inside the endoplasmic reticulum of tumor <span class="hlt">plasma</span> cells. Very few particles were seen outside the cells or in ultracentrifuged preparations of the <span class="hlt">plasma</span> or ascites fluid. In very early tumors particles were occasionally seen free in the cytoplasm adjacent to finely granular material. In general, the distribution of these particles inside endoplasmic reticulum is similar in early and late tumors. A few transplanted X5563 tumors of C3H mice were also examined. Large numbers of particles were found in the region of the Golgi apparatus in late X5663 tumors. A newly described cytoplasmic structure of <span class="hlt">plasma</span> cells, here called a "granular body," appears to be associated with the formation of the particles. Particles present in MPC-1 tumors are exclusively of a doughnut form, whereas some of those in the inclusions of the late X5563 tumors show a dense center. Normal <span class="hlt">plasma</span> cells, produced by inoculation of a modified Freund adjuvant into BALB/c mice. have been compared morphologically with tumor <span class="hlt">plasma</span> cells of both tumor lines. PMID:13733008</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2001APS..DPPCO2003M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2001APS..DPPCO2003M&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Electron</span>-beam generated <span class="hlt">plasmas</span> for processing applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meger, Robert; Leonhardt, Darrin; Murphy, Donald; Walton, Scott; Blackwell, David; Fernsler, Richard; Lampe, Martin; Manheimer, Wallace</p> <p>2001-10-01</p> <p>NRL's Large Area <span class="hlt">Plasma</span> Processing System (LAPPS) utilizes a 5-10 mA/cm^2, 2-4 kV, 1 cm x 30-60 cm cross section beam of <span class="hlt">electrons</span> guided by a magnetic field to ionize a low density (10-100 mTorr) gas.[1] Beam ionization allows large area, high density, low temperature <span class="hlt">plasmas</span> to be generated in an arbitrary gas mixture at a well defined location. Energy and composition of particle fluxes to surfaces on both sides of the <span class="hlt">plasma</span> can be controlled by gas mixture, location, rf bias, and other factors. Experiments have been performed using both pulsed and cw beams. Extensive diagnostics (Langmuir probes, mass and ion energy analyzers, optical emissions, microwave interferometry, etc.) have been fielded to measure the <span class="hlt">plasma</span> properties and neutral particle fluxes (ions, neutrals, free radicals) with and without rf bias on nearby surfaces both with the beam on and off. Uniform, cold (Te < 1eV), dense (ne 10^13 cm-3) <span class="hlt">plasmas</span> in molecular and atomic gases and mixtures thereof have been produced in agreement with theoretical expectations. Initial tests of LAPPS application such as ashing, etching, sputtering, and diamond growth have been performed. Program status will be presented. [1]R.A. Meger, et al, Phys. of <span class="hlt">Plasmas</span> 8(5), p. 2558 (2001)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4169717','PMC'); return false;" href="https://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('https://www.ncbi.nlm.nih.gov/pubmed/24929924','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24929924"><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="https://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 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 MoS2₂ layers.</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.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://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://www.osti.gov/scitech/biblio/6044730','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6044730"><span id="translatedtitle"><span class="hlt">Electron</span> acceleration in a 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>Kochmarev, L.IU.; Liakhov, S.B.; Maiorov, A.D.; Managadze, G.G.; Chmil, A.I.</p> <p>1985-05-01</p> <p>The results of recent laboratory experiments on the distribution function of <span class="hlt">electrons</span>, which are scattered from a beam-<span class="hlt">plasma</span> discharge, are reported. The experimental conditions approximated those during the Gruziya-60-Spurt active rocket-borne experiment to measure the injection of <span class="hlt">electron</span> beams into space near the earth. The beam <span class="hlt">plasma</span>-discharge was ignited in a vacuum chamber by means of a pulsed <span class="hlt">electron</span> beam. The energy of the beam was 2.1 keV, and the current was 150-300 mA. The pressure range corresponding to the <span class="hlt">plasma</span> discharge was 0.0001-0.001 torr. <span class="hlt">Electron</span> distribution was measured using an analyzer which was moved along the chamber axis at a distance L = 75-210 cm from the injector. The experimental results support one possible explanation for the anomalously high sonde potential observed in the Gruziya-60-Spurt experiment: spontaneous changes of the interaction regime shortly after the beginning of the injection pulse. 12 references.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19970040338&hterms=Estado&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DEstado','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19970040338&hterms=Estado&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DEstado"><span id="translatedtitle">Excitation of <span class="hlt">Plasma</span> Waves in Aurora by <span class="hlt">Electron</span> Beams</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>daSilva, C. E.; Vinas, A. F.; deAssis, A. S.; deAzevedo, C. A.</p> <p>1996-01-01</p> <p>In this paper, we study numerically the excitation of <span class="hlt">plasma</span> waves by <span class="hlt">electron</span> beams, in the auroral region above 2000 km of altitude. We have solved the fully kinetic dispersion relation, using numerical method and found the real frequency and the growth rate of the <span class="hlt">plasma</span> wave modes. We have examined the instability properties of low-frequency waves such as the Electromagnetic Ion Cyclotron (EMIC) wave as well as Lower-Hybrid (LH) wave in the range of high-frequency. In all cases, the source of free energy are <span class="hlt">electron</span> beams propagating parallel to the geomagnetic field. We present some features of the growth rate modes, when the cold <span class="hlt">plasma</span> parameters are changed, such as background <span class="hlt">electrons</span> and ions species (H(+) and O(+)) temperature, density or the <span class="hlt">electron</span> beam density and/or drift velocity. These results can be used in a test-particle simulation code, to investigate the ion acceleration and their implication in the auroral acceleration processes, by wave-particle interaction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DPPBO5008T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DPPBO5008T"><span id="translatedtitle">Temperature evolution of strongly coupled <span class="hlt">electron</span>-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>Tiwari, Sanat Kumar; Shaffer, Nathaniel; Baalrud, Scott D.</p> <p>2015-11-01</p> <p>Molecular dynamics simulations of <span class="hlt">electron</span>-ion <span class="hlt">plasmas</span> have been carried out, focusing on the classical strongly coupled regime relevant to ultracold neutral <span class="hlt">plasmas</span>. The interaction of oppositely charged species is modeled using a pseudopotential with a repulsive core at a specified distance ɛ in units of average interparticle spacing. This parameter distinguishes classical from quantum statistical regimes. Simulations are initiated with an equilibration phase in which ions and <span class="hlt">electrons</span> are held to fixed independent temperatures using a thermostat. Subsequently, the thermostats are removed and the system is allowed to evolve. Two effects are observed: (1) For sufficiently small values of ɛ, the <span class="hlt">plasma</span> rapidly heats, (2) <span class="hlt">electrons</span> and ions equilibrate on a longer time scale. The critical ɛ value for the onset of heating and the temperature equilibration rate are compared with existing theory. Excess pressure is calculated in each case based on the equilibrium radial distribution functions obtained during the equilibration phase. The Γ - ɛ phase space is explored, revealing qualitative differences in the temperature evolution due to <span class="hlt">electron</span>-ion interactions in the classical and quantum regimes. The authors gratefully acknowledge support from NSF grant PHY-1453736.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1992PNAS...8911126S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1992PNAS...8911126S"><span id="translatedtitle">Requirement for Coenzyme Q in <span class="hlt">Plasma</span> Membrane <span class="hlt">Electron</span> Transport</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, I. L.; Sun, E. E.; Crane, F. L.; Morre, D. J.; Lindgren, A.; Low, H.</p> <p>1992-12-01</p> <p>Coenzyme Q is required in the <span class="hlt">electron</span> transport system of rat hepatocyte and human erythrocyte <span class="hlt">plasma</span> membranes. Extraction of coenzyme Q from the membrane decreases NADH dehydrogenase and NADH:oxygen oxidoreductase activity. Addition of coenzyme Q to the extracted membrane restores the activity. Partial restoration of activity is also found with α-tocopherylquinone, but not with vitamin K_1. Analogs of coenzyme Q inhibit NADH dehydrogenase and oxidase activity and the inhibition is reversed by added coenzyme Q. Ferricyanide reduction by transmembrane <span class="hlt">electron</span> transport from HeLa cells is inhibited by coenzyme Q analogs and restored with added coenzyme Q10. Reduction of external ferricyanide and diferric transferrin by HeLa cells is accompanied by proton release from the cells. Inhibition of the reduction by coenzyme Q analogs also inhibits the proton release, and coenzyme Q10 restores the proton release activity. Trans-<span class="hlt">plasma</span> membrane <span class="hlt">electron</span> transport stimulates growth of serum-deficient cells, and added coenzyme Q10 increases growth of HeLa (human adenocarcinoma) and BALB/3T3 (mouse fibroblast) cells. The evidence is consistent with a function for coenzyme Q in a trans-<span class="hlt">plasma</span> membrane <span class="hlt">electron</span> transport system which influences cell growth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JPhD...46m5201L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JPhD...46m5201L"><span id="translatedtitle">Secondary <span class="hlt">electron</span> induced asymmetry in capacitively 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>Lafleur, T.; Chabert, P.; Booth, J. P.</p> <p>2013-04-01</p> <p>Using a simple analytical model, together with a 1D particle-in-cell simulation, we show that it is possible to generate an asymmetric <span class="hlt">plasma</span> response in a sinusoidally excited, geometrically symmetric, capacitively coupled <span class="hlt">plasma</span> (CCP). The asymmetric response is produced using rf electrodes of differing materials, and hence different secondary <span class="hlt">electron</span> emission coefficients. This asymmetry in the emission coefficients can produce a significant, measurable dc bias voltage (Vbias/Vrf ˜ 0-0.2), together with an asymmetry in the <span class="hlt">plasma</span> density profiles and ion flux to each electrode. The dc bias formation can be understood from a particle-flux balance applied to each electrode, and results from two main effects: (1) the larger effective ion flux at each electrode due to the emission of secondary <span class="hlt">electrons</span> and (2) ion-flux multiplication within the sheath due to ionization from these emitted secondary <span class="hlt">electrons</span>. By making use of an empirical fit to the simulation data, the possibility of non-invasively estimating secondary <span class="hlt">electron</span> emission coefficients in CCP systems 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_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://www.osti.gov/scitech/biblio/22403284','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22403284"><span id="translatedtitle">Collimated fast <span class="hlt">electron</span> beam generation in critical density <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Iwawaki, T. Habara, H.; Morita, K.; Tanaka, K. A.; Baton, S.; Fuchs, J.; Chen, S.; Nakatsutsumi, M.; Rousseaux, C.; Filippi, F.; Nazarov, W.</p> <p>2014-11-15</p> <p>Significantly collimated fast <span class="hlt">electron</span> beam with a divergence angle 10° (FWHM) is observed when an ultra-intense laser pulse (I = 10{sup 14 }W/cm{sup 2}, 300 fs) irradiates a uniform critical density <span class="hlt">plasma</span>. The uniform <span class="hlt">plasma</span> is created through the ionization of an ultra-low density (5 mg/c.c.) plastic foam by X-ray burst from the interaction of intense laser (I = 10{sup 14 }W/cm{sup 2}, 600 ps) with a thin Cu foil. 2D Particle-In-Cell (PIC) simulation well reproduces the collimated <span class="hlt">electron</span> beam with a strong magnetic field in the region of the laser pulse propagation. To understand the physical mechanism of the collimation, we calculate energetic <span class="hlt">electron</span> motion in the magnetic field obtained from the 2D PIC simulation. As the results, the strong magnetic field (300 MG) collimates <span class="hlt">electrons</span> with energy over a few MeV. This collimation mechanism may attract attention in many applications such as <span class="hlt">electron</span> acceleration, <span class="hlt">electron</span> microscope and fast ignition of laser fusion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PPCF...58g5004O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PPCF...58g5004O"><span id="translatedtitle"><span class="hlt">Plasma</span> sheath in the presences of non-Maxwellian energetic <span class="hlt">electrons</span> and secondary emission <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>Ou, Jing; Lin, Binbin; Zhao, Xiaoyun; Yang, Youlei</p> <p>2016-07-01</p> <p>The formation of a sheath in front of a carbon or tungsten material plane immersed in a <span class="hlt">plasma</span> containing non-Maxwellian energetic <span class="hlt">electrons</span> and secondary emission <span class="hlt">electrons</span> is studied using a 1D model. In the model, energetic <span class="hlt">electrons</span> are described by the <span class="hlt">electron</span> energy distribution function (EEDF) and secondary <span class="hlt">electron</span> emission (SEE) is produced by the <span class="hlt">electrons</span> impinging on the wall. It is found that SEE coefficient depends on not only the sheath potential but also the EEDF profile of energetic <span class="hlt">electrons</span> when a non-Maxwellian energetic <span class="hlt">electron</span> component is present. The energetic <span class="hlt">electrons</span> and associated secondary emission <span class="hlt">electrons</span> can strongly modify ion velocity at sheath edge, floating potential and I–V probe characteristic. Due to the interdependence between SEE coefficient originating from the impact of non-Maxwellian energetic <span class="hlt">electrons</span> on the wall and the sheath potential, with the increase in the energy of energetic <span class="hlt">electrons</span>, a sudden jump phenomenon can be found in the profiles of SEE coefficient and other quantities such as floating potential and ion velocity at the sheath edge for tungsten wall, while for carbon wall they are the continuous variation. To begin with, the energetic <span class="hlt">electron</span> component does not dominate the sheath, and I–V probe characteristic depends on both the EEDF profile of energetic <span class="hlt">electrons</span> and material properties. Once the energetic <span class="hlt">electron</span> component dominates the sheath, the analysis of I–V probe characteristic will yield the energy of energetic <span class="hlt">electrons</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23256505','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23256505"><span id="translatedtitle">Evolution of <span class="hlt">electronic</span> structure in atomically thin <span class="hlt">sheets</span> of WS2 and WSe2.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhao, Weijie; Ghorannevis, Zohreh; Chu, Leiqiang; Toh, Minglin; Kloc, Christian; Tan, Ping-Heng; Eda, Goki</p> <p>2013-01-22</p> <p>Geometrical confinement effect in exfoliated <span class="hlt">sheets</span> of layered materials leads to significant evolution of energy dispersion in mono- to few-layer thickness regime. Molybdenum disulfide (MoS(2)) was recently found to exhibit indirect-to-direct gap transition when the thickness is reduced to a single monolayer. Emerging photoluminescence (PL) from monolayer MoS(2) opens up opportunities for a range of novel optoelectronic applications of the material. Here we report differential reflectance and PL spectra of mono- to few-layer WS(2) and WSe(2) that indicate that the band structure of these materials undergoes similar indirect-to-direct gap transition when thinned to a single monolayer. The transition is evidenced by distinctly enhanced PL peak centered at 630 and 750 nm in monolayer WS(2) and WSe(2), respectively. Few-layer flakes are found to exhibit comparatively strong indirect gap emission along with direct gap hot <span class="hlt">electron</span> emission, suggesting high quality of synthetic crystals prepared by a chemical vapor transport method. Fine absorption and emission features and their thickness dependence suggest a strong effect of Se p-orbitals on the d <span class="hlt">electron</span> band structure as well as interlayer coupling in WSe(2).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014NucFu..54d3006L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014NucFu..54d3006L&link_type=ABSTRACT"><span id="translatedtitle">Trapped <span class="hlt">electron</span> effects on ηi-mode and trapped <span class="hlt">electron</span> mode in RFP <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>Liu, S. F.; Guo, S. C.; Kong, W.; Dong, J. Q.</p> <p>2014-04-01</p> <p>The drift instabilities in the toroidal reversed field pinch (RFP) <span class="hlt">plasmas</span> are numerically studied with gyrokinetic integral eigenmode equations, by taking into account the trapped <span class="hlt">electrons</span> (TEs) and full ion kinetic effects. Both the collisionless and collisional <span class="hlt">plasmas</span> are investigated. Two topics are addressed: the TE effects on the ion temperature gradient driven mode, and the instability of the trapped <span class="hlt">electron</span> mode (TEM). A comparison with a circular tokamak configuration has been made. Although the TEs generally play a similar role in RFPs as they do in tokamaks, their effects become significant in RFPs only when very steep density/temperature profiles exist. Indeed, the instability of the TEM in RFP <span class="hlt">plasmas</span> requires a much steeper density/temperature gradient and has a much narrower kθρs spectrum than in tokamak <span class="hlt">plasmas</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..DPPJP8048P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..DPPJP8048P"><span id="translatedtitle"><span class="hlt">Electron</span> Temperature and Potential Measurements in a Helicon <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>Plank, J.; Hayes, T. R.; Gilmore, M.</p> <p>2013-10-01</p> <p>Measurements of <span class="hlt">plasma</span> potential, floating potential, and <span class="hlt">electron</span> temperature, Te, are notoriously difficult in RF-produced <span class="hlt">plasmas</span> such as helicons. This work presents comparisons of potential and Te measurements made via swept and stepped compensated and uncompensated single and double Langmuir probes, emissive probes, and static triple probes. These measurements have been made in the HelCat (Helicon-Cathode) linear <span class="hlt">plasma</span> device at the University of New Mexico using HelCat's helicon source. HelCat is a 4 m long, 0.5 m diameter device with magnetic field, B0 <2.2 kG, and typical densities n ~ 1018 - 1020 m-3. Comparisons between the measurements and expected theoretical differences will be presented. Supported by US National Science Foundation Award 1201995.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900031715&hterms=beam+diagnostics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dbeam%2Bdiagnostics','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900031715&hterms=beam+diagnostics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dbeam%2Bdiagnostics"><span id="translatedtitle"><span class="hlt">Plasma</span> heating, electric fields and <span class="hlt">plasma</span> flow by <span class="hlt">electron</span> beam ionospheric injection</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>1990-01-01</p> <p>The electric fields and the floating potentials of a <span class="hlt">Plasma</span> Diagnostics Payload (PDP) located near a powerful <span class="hlt">electron</span> beam injected from a large sounding rocket into the auroral zone ionosphere have been studied. As the PDP drifted away from the beam laterally, it surveyed a region of hot <span class="hlt">plasma</span> extending nearly to 60 m radius. Large polarization electric fields transverse to B were imbedded in this hot <span class="hlt">plasma</span>, which displayed large ELF wave variations and also an average pattern which has led to a model of the <span class="hlt">plasma</span> flow about the negative line potential of the beam resembling a hydrodynamic vortex in a uniform flow field. Most of the present results are derived from the ECHO 6 sounding rocket mission.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PhDT........67C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PhDT........67C"><span id="translatedtitle"><span class="hlt">Plasma</span> <span class="hlt">electron</span> temperature and the entropy effect on hydrogen production</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chakartnarodom, Parinya</p> <p></p> <p> that atomic hydrogen is produced in the <span class="hlt">plasma</span>, and the results from flue-gas analyzer show that H 2 is a product from the reaction in the <span class="hlt">plasma</span>. From the experimental results, the yield of H2 is increased with the increasing of the <span class="hlt">electron</span> temperature in gas/gas <span class="hlt">plasma</span> reactions having positive entropy. For solid/gas <span class="hlt">plasma</span> reactions which DeltaSo is either positive or negative, there is no correlation between H2 yield and <span class="hlt">electron</span> temperature. However, H2 yield from all <span class="hlt">plasma</span> reactions is lower than the prediction from the van't Hoff equation. Based on an analysis of the Saha equation, the effective temperature of the chemical species in the <span class="hlt">plasma</span> may be lower than the <span class="hlt">electron</span> temperature, thus rationalizing our observation of reduced H2 yield. An alternative hypothesis is that the quenching rates of the products from the <span class="hlt">plasma</span> are not fast enough to avoid recombination of the reaction products at low temperature, where the enthalpy term dominates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21421239','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21421239"><span id="translatedtitle">Possible excitation of solitary <span class="hlt">electron</span> holes in a laboratory <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kar, S.; Mukherjee, S.; Ravi, G.; Saxena, Y. C.</p> <p>2010-10-15</p> <p><span class="hlt">Plasma</span> response to a fast rising high positive voltage pulse is experimentally studied in a uniform and unmagnetized <span class="hlt">plasma</span>. The pulse is applied to a metallic disk electrode immersed in a low pressure argon <span class="hlt">plasma</span> (n{sub p{approx}}10{sup 9} cm{sup -3} and T{sub e{approx}}0.5-2 eV) with the pulse magnitude U{sub 0}>>kT{sub e}/e, where T{sub e} is the <span class="hlt">electron</span> temperature. Experiments have been carried out for various applied pulse widths {tau}{sub p} ranging from less than 3f{sub i}{sup -1} to greater than 3f{sub i}{sup -1}, where f{sub i} is the ion <span class="hlt">plasma</span> frequency. For pulse widths less than 3f{sub i}{sup -1}, potential disturbances are observed to propagate in two opposite directions from a location different from the actual exciter (metal disk electrode), indicating the presence of a virtual source. For pulse widths equal or greater than 3f{sub i}{sup -1}, there is no indication of such virtual source. These disturbances propagate with two phase speeds, i.e., v{sub p}/v{sub e}=1.36{+-}0.11 and 0.4{+-}0.15, where v{sub e} is the <span class="hlt">electron</span> thermal speed. It is also observed that by increasing <span class="hlt">plasma</span> density, the speed of these disturbances increases, whereas the speed is independent of pulse magnitude. Analysis of these disturbances indicates the excitation of solitary <span class="hlt">electron</span> holes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JPhCS.370a2012V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JPhCS.370a2012V"><span id="translatedtitle">Application of <span class="hlt">electron</span> beam <span class="hlt">plasma</span> for biopolymers modification</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vasilieva, T. M.</p> <p>2012-06-01</p> <p>The effects of the <span class="hlt">Electron</span> Beam <span class="hlt">Plasma</span> treatment on natural polysaccharide chitosan were studied experimentally. Low molecular water-soluble products of chitosan and chitooligosaccharides were obtained by treating the original polymers in the <span class="hlt">Electron</span> Beam <span class="hlt">Plasma</span> of oxygen and water vapor. The molecular mass of the products varied from 18 kDa to monomeric fragments. The degradation of the original polymers was due to the action of active oxygen particles (atomic and singlet oxygen) and the particles of the water plasmolysis (hydroxyl radicals, hydrogen peroxides). The 95% yield of low molecular weight chitosans was attained by optimizing the treatment conditions. The studies of the antimicrobial activity of low molecular products showed that they strongly inhibit the multiplication of colon bacillus, aurococcus and yeast-like fungi. The EBP-stimulated degradation of polysaccharides and proteins were found to result from breaking β-1,4 glycosidic bounds and peptide bonds, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/503654','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/503654"><span id="translatedtitle">Neoclassical <span class="hlt">electron</span> and ion transport in toroidally rotating <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sugama, H.; Horton, W.</p> <p>1997-06-01</p> <p>Neoclassical transport processes of <span class="hlt">electrons</span> and ions are investigated in detail for toroidally rotating axisymmetric <span class="hlt">plasmas</span> with large flow velocities on the order of the ion thermal speed. The Onsager relations for the flow-dependent neoclassical transport coefficients are derived from the symmetry properties of the drift kinetic equation with the self-adjoint collision operator. The complete neoclassical transport matrix with the Onsager symmetry is obtained for the rotating <span class="hlt">plasma</span> consisting of <span class="hlt">electrons</span> and single-species ions in the Pfirsch{endash}Schl{umlt u}ter and banana regimes. It is found that the inward banana fluxes of particles and toroidal momentum are driven by the parallel electric field, which are phenomena coupled through the Onsager symmetric off-diagonal coefficients to the parallel currents caused by the radial thermodynamic forces conjugate to the inward fluxes, respectively. {copyright} {ital 1997 American Institute of Physics.}</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009PhPl...16l2701M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009PhPl...16l2701M&link_type=ABSTRACT"><span id="translatedtitle">Study of <span class="hlt">plasma</span> heating induced by fast <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>Morace, A.; Magunov, A.; Batani, D.; Redaelli, R.; Fourment, C.; Santos, J. J.; Malka, G.; Boscheron, A.; Casner, A.; Nazarov, W.; Vinci, T.; Okano, Y.; Inubushi, Y.; Nishimura, H.; Flacco, A.; Spindloe, C.; Tolley, M.</p> <p>2009-12-01</p> <p>We studied the induced <span class="hlt">plasma</span> heating in three different kinds of targets: mass limited, foam targets, and large mass targets. The experiment was performed at Alisé Laser Facility of CEA/CESTA. The laser system emitted a ˜1 ps pulse with ˜10 J energy at a wavelength of ˜1 μm. Mass limited targets had three layers with thicknesses of 10 μm C8H8, 1 μm C8H7Cl, and 10 μm C8H8 with size of 100×100 μm2. Detailed spectroscopic analysis of x rays emitted from the Cl tracer showed that it was possible to heat up the <span class="hlt">plasma</span> from mass limited targets to a temperature of ˜250 eV with density of ˜1021 cm-3. The <span class="hlt">plasma</span> heating is only produced by fast <span class="hlt">electron</span> transport in the target, being the 10 μm C8H8 overcoating thick enough to prevent any possible direct irradiation of the tracer layer even taking into account mass-ablation due to the prepulse. These results demonstrate that with mass limited targets, it is possible to generate a <span class="hlt">plasma</span> heated up to several hundreds eV. It is also very important for research concerning high energy density phenomena and for fast ignition (in particular for the study of fast <span class="hlt">electrons</span> transport and induced heating).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..DPPYO6007J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..DPPYO6007J"><span id="translatedtitle">Cathode <span class="hlt">Plasma</span> Formation in High Intensity <span class="hlt">Electron</span> Beam Diodes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Johnston, Mark; Kiefer, Mark; Oliver, Bryan; Bennett, Nichelle; Droemer, Darryl; Bernshtam, V.; Doron, R.; Maron, Yitzhak</p> <p>2013-10-01</p> <p>This talk will detail the experimental results and conclusions obtained for cathode <span class="hlt">plasma</span> formation on the Self-Magnetic Pinch (SMP) diode fielded on the RITS-6 accelerator (4-7.5 MeV) at Sandia National Laboratories. The SMP diode utilizes a hollowed metal cathode to produce high power (TW), focused <span class="hlt">electron</span> beams (<3 mm diameter) which are used for flash x-ray radiography applications. Optical diagnostics include high speed (<10 ns) framing cameras, optical streak cameras, and spectroscopy. The cathode <span class="hlt">plasma</span> in this high electric (MV/cm) and magnetic (>10 Tesla) field environment forms well-defined striations. These striations have been examined for a number of different cathode sizes, vacuum gap spacings, and diode voltages. Optical streak images have been taken to determine the time evolution of the <span class="hlt">plasma</span>, and optical spectroscopy has been employed to determine its constituents as well as their densities and temperatures inferred from detailed time-dependent, collisional-radiative (CR) and radiation transport modelings. Comments will be made as to the overall effect of the cathode <span class="hlt">plasma</span> in regards to the diode impedance and <span class="hlt">electron</span> beam focusing. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21550326','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21550326"><span id="translatedtitle"><span class="hlt">Plasma</span> Jet Braking: Energy Dissipation and Nonadiabatic <span class="hlt">Electrons</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Khotyaintsev, Yu. V.; Cully, C. M.; Vaivads, A.; Andre, M.; Owen, C. J.</p> <p>2011-04-22</p> <p>We report in situ observations by the Cluster spacecraft of wave-particle interactions in a magnetic flux pileup region created by a magnetic reconnection outflow jet in Earth's magnetotail. Two distinct regions of wave activity are identified: lower-hybrid drift waves at the front edge and whistler-mode waves inside the pileup region. The whistler-mode waves are locally generated by the <span class="hlt">electron</span> temperature anisotropy, and provide evidence for ongoing betatron energization caused by magnetic flux pileup. The whistler-mode waves cause fast pitch-angle scattering of <span class="hlt">electrons</span> and isotropization of the <span class="hlt">electron</span> distribution, thus making the flow braking process nonadiabatic. The waves strongly affect the <span class="hlt">electron</span> dynamics and thus play an important role in the energy conversion chain during <span class="hlt">plasma</span> jet braking.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhPl...23g2302S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhPl...23g2302S"><span id="translatedtitle"><span class="hlt">Plasma</span> relaxation and topological aspects in <span class="hlt">electron</span> magnetohydrodynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shivamoggi, B. K.</p> <p>2016-07-01</p> <p>Parker's formulation of isotopological <span class="hlt">plasma</span> relaxation process toward minimum magnetics energy states in magnetohydrodynamics (MHD) is extended to <span class="hlt">electron</span> MHD (EMHD). The lower bound on magnetic energy in EMHD is determined by both the magnetic field and the <span class="hlt">electron</span> vorticity field topologies, and is shown to be reduced further in EMHD by an amount proportional to the sum of total <span class="hlt">electron</span>-flow kinetic energy and total <span class="hlt">electron</span>-flow enstrophy. The EMHD Beltrami condition becomes equivalent to the potential vorticity conservation equation in two-dimensional (2D) hydrodynamics, and the torsion coefficient α turns out to be proportional to potential vorticity. The winding pattern of the magnetic field lines appears to evolve, therefore, in the same way as potential vorticity lines in 2D hydrodynamics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23679533','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23679533"><span id="translatedtitle"><span class="hlt">Plasma</span> expansion into vacuum assuming a steplike <span class="hlt">electron</span> energy distribution.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kiefer, Thomas; Schlegel, Theodor; Kaluza, Malte C</p> <p>2013-04-01</p> <p>The expansion of a semi-infinite <span class="hlt">plasma</span> slab into vacuum is analyzed with a hydrodynamic model implying a steplike <span class="hlt">electron</span> energy distribution function. Analytic expressions for the maximum ion energy and the related ion distribution function are derived and compared with one-dimensional numerical simulations. The choice of the specific non-Maxwellian initial <span class="hlt">electron</span> energy distribution automatically ensures the conservation of the total energy of the system. The estimated ion energies may differ by an order of magnitude from the values obtained with an adiabatic expansion model supposing a Maxwellian <span class="hlt">electron</span> distribution. Furthermore, good agreement with data from experiments using laser pulses of ultrashort durations τ(L)</~80fs is found, while this is not the case when a hot Maxwellian <span class="hlt">electron</span> distribution is assumed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21428811','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21428811"><span id="translatedtitle">Ultrafast Diagnostics for <span class="hlt">Electron</span> Beams from Laser <span class="hlt">Plasma</span> Accelerators</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Matlis, N. H.; Bakeman, M.; Geddes, C. G. R.; Gonsalves, T.; Lin, C.; Nakamura, K.; Osterhoff, J.; Plateau, G. R.; Schroeder, C. B.; Shiraishi, S.; Sokollik, T.; Tilborg, J. van; Toth, Cs.; Leemans, W. P.</p> <p>2010-11-04</p> <p>We present an overview of diagnostic techniques for measuring key parameters of <span class="hlt">electron</span> bunches from Laser <span class="hlt">Plasma</span> Accelerators (LPAs). The diagnostics presented here were chosen because they highlight the unique advantages (e.g. diverse forms of electromagnetic emission) and difficulties (e.g. shot-to-shot variability) associated with LPAs. Non destructiveness and high resolution (in space and time and energy) are key attributes that enable the formation of a comprehensive suite of simultaneous diagnostics which are necessary for the full characterization of the ultrashort, but highly-variable <span class="hlt">electron</span> bunches from LPAs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1022732','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1022732"><span id="translatedtitle">Ultrafast Diagnostics for <span class="hlt">Electron</span> Beams from Laser <span class="hlt">Plasma</span> Accelerators</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Matlis, N. H.; Bakeman, M.; Geddes, C. G. R.; Gonsalves, T.; Lin, C.; Nakamura, K.; Osterhoff, J.; Plateau, G. R.; Schroeder, C. B.; Shiraishi, S.; Sokollik, T.; van Tilborg, J.; Toth, Cs.; Leemans, W. P.</p> <p>2010-06-01</p> <p>We present an overview of diagnostic techniques for measuring key parameters of <span class="hlt">electron</span> bunches from Laser <span class="hlt">Plasma</span> Accelerators (LPAs). The diagnostics presented here were chosen because they highlight the unique advantages (e.g., diverse forms of electromagnetic emission) and difficulties (e.g., shot-to-shot variability) associated with LPAs. Non destructiveness and high resolution (in space and time and energy) are key attributes that enable the formation of a comprehensive suite of simultaneous diagnostics which are necessary for the full characterization of the ultrashort, but highly-variable <span class="hlt">electron</span> bunches from LPAs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006EPJAP..34..225A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006EPJAP..34..225A"><span id="translatedtitle">Extraction of <span class="hlt">electron</span> <span class="hlt">plasma</span> energy distribution function using distortion meters</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Azooz, A. A.</p> <p>2006-06-01</p> <p>A new method for direct evaluation of the <span class="hlt">electron</span> energy distribution function in <span class="hlt">plasmas</span> is suggested, which involves the use of audio frequencies distortion factor meters. The amount of distortion suffered by a Langmuir probe AC current produced by superimposing a clean AC voltage on the DC probe voltage is measured. Although such distortions are proportional to the second derivative of the probe characteristic at any point when its neighborhood can be approximated by a second-degree polynomial, the instrument function is always sharper than that of harmonic differentiation. The method is analyzed theoretically, and tested experimentally. It is also shown that distortion additionally provides a direct measure of the <span class="hlt">electron</span> temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/378146','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/378146"><span id="translatedtitle">Laser driven <span class="hlt">electron</span> acceleration in vacuum, gases and <span class="hlt">plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sprangle, P.; Esarey, E.; Krall, J.</p> <p>1996-04-19</p> <p>This paper discusses some of the important issues pertaining to laser acceleration in vacuum, neutral gases and <span class="hlt">plasmas</span>. The limitations of laser vacuum acceleration as they relate to <span class="hlt">electron</span> slippage, laser diffraction, material damage and <span class="hlt">electron</span> aperture effects, are discussed. An inverse Cherenkov laser acceleration configuration is presented in which a laser beam is self guided in a partially ionized gas. Optical self guiding is the result of a balance between the nonlinear self focusing properties of neutral gases and the diffraction effects of ionization. The stability of self guided beams is analyzed and discussed. In addition, aspects of the laser wakefield accelerator are presented and laser driven accelerator experiments are briefly discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009PhPl...16l2112C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009PhPl...16l2112C"><span id="translatedtitle">Dressed solitons in quantum <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>Chatterjee, Prasanta; Roy, Kaushik; Mondal, Ganesh; Muniandy, S. V.; Yap, S. L.; Wong, C. S.</p> <p>2009-12-01</p> <p>Nonlinear propagation of quantum ion acoustic waves in a dense quantum <span class="hlt">plasma</span> whose constituents are <span class="hlt">electrons</span>, positrons, and positive ions is investigated using a quantum hydrodynamic model. The Korteweg-de Vries equation is derived using reductive perturbation technique. The higher order inhomogeneous differential equation is obtained for the dressed soliton. The dynamical equation for dressed soliton is solved using the renormalization method. The conditions for the validity of the higher order correction are described. The effects of quantum parameter, positron concentration, <span class="hlt">electron</span> to positron Fermi temperature ratio, and soliton velocity on the amplitude and width of the dressed soliton are studied.</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/2016NIMPA.829..104F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NIMPA.829..104F"><span id="translatedtitle">A "slingshot" laser-driven acceleration mechanism of <span class="hlt">plasma</span> <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>Fiore, Gaetano; De Nicola, Sergio</p> <p>2016-09-01</p> <p>We briefly report on the recently proposed Fiore et al. [1] and Fiore and De Nicola [2] <span class="hlt">electron</span> acceleration mechanism named "slingshot effect": under suitable conditions the impact of an ultra-short and ultra-intense laser pulse against the surface of a low-density <span class="hlt">plasma</span> is expected to cause the expulsion of a bunch of superficial <span class="hlt">electrons</span> with high energy in the direction opposite to that of the pulse propagation; this is due to the interplay of the huge ponderomotive force, huge longitudinal field arising from charge separation, and the finite size of the laser spot.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22093652','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22093652"><span id="translatedtitle">Temperature diagnostics of ECR <span class="hlt">plasma</span> by measurement of <span class="hlt">electron</span> bremsstrahlung</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kasthurirangan, S.; Agnihotri, A. N.; Desai, C. A.; Tribedi, L. C.</p> <p>2012-07-15</p> <p>The x-ray bremsstrahlung spectrum emitted by the <span class="hlt">electron</span> population in a 14.5 GHz ECR <span class="hlt">plasma</span> source has been measured using a NaI(Tl) detector, and hence the <span class="hlt">electron</span> temperature of the higher energy <span class="hlt">electron</span> population in the <span class="hlt">plasma</span> has been determined. The x-ray spectra for Ne and Ar gases have been systematically studied as a function of inlet gas pressure from 7 Multiplication-Sign 10{sup -7} mbar to 7 Multiplication-Sign 10{sup -5} mbar and for input microwave power {approx}1 W to {approx}300 W. At the highest input power and optimum pressure conditions, the end point bremsstrahlung energies are seen to reach {approx}700 keV. The estimated <span class="hlt">electron</span> temperatures (T{sub e}) were found to be in the range 20 keV-80 keV. The T{sub e} is found to be peaking at a pressure of 1 Multiplication-Sign 10{sup -5} mbar for both gases. The T{sub e} is seen to increase with increasing input power in the intermediate power region, i.e., between 100 and 200 W, but shows different behaviour for different gases in the low and high power regions. Both gases show very weak dependence of <span class="hlt">electron</span> temperature on inlet gas pressure, but the trends in each gas are different.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhDT........41B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhDT........41B"><span id="translatedtitle">Secondary <span class="hlt">electron</span> emission from <span class="hlt">plasma</span> processed accelerating cavity grade niobium</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Basovic, Milos</p> <p></p> <p> by different techniques. Specifically, this work provides the results of SEY from the <span class="hlt">plasma</span> cleaned cavity grade niobium (Nb) samples. Pure niobium is currently the material of choice for the fabrication of Superconducting Radio Frequency (SRF) cavities. The effect of <span class="hlt">plasma</span> processing with two different gases will be examined in two groups of samples. The first group of samples is made from cavity grade niobium. The second group of samples is made from the same material, but include a welded joint made by <span class="hlt">electron</span> beam welding, since in niobium SRF cavities the peak electric and magnetic field are seen in close proximity to the welded joints. Both groups of samples will be exposed to nitrogen (N2) and a mixture of argon with oxygen (Ar/O2) <span class="hlt">plasma</span>. It is the goal of this research to determine the SEY on these two groups of samples before and after <span class="hlt">plasma</span> processing as a function of the energy of primary <span class="hlt">electrons</span>. The SEY as a function of the angle of incidence of the primary <span class="hlt">electrons</span> is tested on the samples treated with Ar/O2 <span class="hlt">plasma</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090043095','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090043095"><span id="translatedtitle">Non-ambipolar radio-frequency <span class="hlt">plasma</span> <span class="hlt">electron</span> source and systems and methods for generating <span class="hlt">electron</span> beams</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hershkowitz, Noah (Inventor); Longmier, Benjamin (Inventor); Baalrud, Scott (Inventor)</p> <p>2009-01-01</p> <p>An <span class="hlt">electron</span> generating device extracts <span class="hlt">electrons</span>, through an <span class="hlt">electron</span> sheath, from <span class="hlt">plasma</span> produced using RF fields. The <span class="hlt">electron</span> sheath is located near a grounded ring at one end of a negatively biased conducting surface, which is normally a cylinder. Extracted <span class="hlt">electrons</span> pass through the grounded ring in the presence of a steady state axial magnetic field. Sufficiently large magnetic fields and/or RF power into the <span class="hlt">plasma</span> allow for helicon <span class="hlt">plasma</span> generation. The ion loss area is sufficiently large compared to the <span class="hlt">electron</span> loss area to allow for total non-ambipolar extraction of all <span class="hlt">electrons</span> leaving the <span class="hlt">plasma</span>. Voids in the negatively-biased conducting surface allow the time-varying magnetic fields provided by the antenna to inductively couple to the <span class="hlt">plasma</span> within the conducting surface. The conducting surface acts as a Faraday shield, which reduces any time-varying electric fields from entering the conductive surface, i.e. blocks capacitive coupling between the antenna and the <span class="hlt">plasma</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110004225','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110004225"><span id="translatedtitle">Non-ambipolar radio-frequency <span class="hlt">plasma</span> <span class="hlt">electron</span> source and systems and methods for generating <span class="hlt">electron</span> beams</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hershkowitz, Noah (Inventor); Longmier, Benjamin (Inventor); Baalrud, Scott (Inventor)</p> <p>2011-01-01</p> <p>An <span class="hlt">electron</span> generating device extracts <span class="hlt">electrons</span>, through an <span class="hlt">electron</span> sheath, from <span class="hlt">plasma</span> produced using RF fields. The <span class="hlt">electron</span> sheath is located near a grounded ring at one end of a negatively biased conducting surface, which is normally a cylinder. Extracted <span class="hlt">electrons</span> pass through the grounded ring in the presence of a steady state axial magnetic field. Sufficiently large magnetic fields and/or RF power into the <span class="hlt">plasma</span> allow for helicon <span class="hlt">plasma</span> generation. The ion loss area is sufficiently large compared to the <span class="hlt">electron</span> loss area to allow for total non-ambipolar extraction of all <span class="hlt">electrons</span> leaving the <span class="hlt">plasma</span>. Voids in the negatively-biased conducting surface allow the time-varying magnetic fields provided by the antenna to inductively couple to the <span class="hlt">plasma</span> within the conducting surface. The conducting surface acts as a Faraday shield, which reduces any time-varying electric fields from entering the conductive surface, i.e. blocks capacitive coupling between the antenna and the <span class="hlt">plasma</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/973142','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/973142"><span id="translatedtitle">Non-ambipolar radio-frequency <span class="hlt">plasma</span> <span class="hlt">electron</span> source and systems and methods for generating <span class="hlt">electron</span> beams</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Hershkowitz, Noah; Longmier, Benjamin; Baalrud, Scott</p> <p>2009-03-03</p> <p>An <span class="hlt">electron</span> generating device extracts <span class="hlt">electrons</span>, through an <span class="hlt">electron</span> sheath, from <span class="hlt">plasma</span> produced using RF fields. The <span class="hlt">electron</span> sheath is located near a grounded ring at one end of a negatively biased conducting surface, which is normally a cylinder. Extracted <span class="hlt">electrons</span> pass through the grounded ring in the presence of a steady state axial magnetic field. Sufficiently large magnetic fields and/or RF power into the <span class="hlt">plasma</span> allow for helicon <span class="hlt">plasma</span> generation. The ion loss area is sufficiently large compared to the <span class="hlt">electron</span> loss area to allow for total non-ambipolar extraction of all <span class="hlt">electrons</span> leaving the <span class="hlt">plasma</span>. Voids in the negatively-biased conducting surface allow the time-varying magnetic fields provided by the antenna to inductively couple to the <span class="hlt">plasma</span> within the conducting surface. The conducting surface acts as a Faraday shield, which reduces any time-varying electric fields from entering the conductive surface, i.e. blocks capacitive coupling between the antenna and the <span class="hlt">plasma</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..GECGT1143N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..GECGT1143N"><span id="translatedtitle">PECVD of SiOC Films Using a <span class="hlt">Sheet</span>-type Atmospheric Pressure <span class="hlt">Plasma</span> Jet</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nakajima, Kouta; Tanaka, Kenji; Shirafuji, Tatsuru</p> <p>2015-09-01</p> <p>Packaging industries have used SiOC thin films for gas barrier coatings on the membranes for packaging foods, drug, and so on. PECVD is the most extensively employed method for preparing the SiOC films. However, PECVD is a process performed at a low pressure in general and requires expensive vacuum systems, especially in the case of large area coatings. Atmospheric pressure PECVD is a candidate to overcome this issue. If we simply apply atmospheric pressure <span class="hlt">plasma</span> to CVD processes, however, we will encounter the problem of particle formation because of the high collision frequency in the environment of atmospheric pressure. In this work, we have developed a reactor that utilizes a unique gas-flow scheme for avoiding the particle formation. We have successfully deposited SiOC films by using this reactor, in which the source material is hexamethyldisiloxane and discharge/carrier gas is He. XPS measurements on the SiOC films have revealed that the films contain relatively higher concentrations of unfavorable methyl groups that reduce gas barrier performances. However, no particulates are involved in and on the deposited films as long as characterizing the films with eye observation and with transmission <span class="hlt">electron</span> microscopy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22408201','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22408201"><span id="translatedtitle">Non-linear <span class="hlt">plasma</span> wake growth of <span class="hlt">electron</span> holes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hutchinson, I. H.; Haakonsen, C. B.; Zhou, C.</p> <p>2015-03-15</p> <p>An object's wake in a <span class="hlt">plasma</span> with small Debye length that drifts across the magnetic field is subject to electrostatic <span class="hlt">electron</span> instabilities. Such situations include, for example, the moon in the solar wind and probes in magnetized laboratory <span class="hlt">plasmas</span>. The instability drive mechanism can equivalently be considered drift down the potential-energy gradient or drift up the density-gradient. The gradients arise because the <span class="hlt">plasma</span> wake has a region of depressed density and electrostatic potential into which ions are attracted along the field. The non-linear consequences of the instability are analysed in this paper. At physical ratios of <span class="hlt">electron</span> to ion mass, neither linear nor quasilinear treatment can explain the observation of large-amplitude perturbations that disrupt the ion streams well before they become ion-ion unstable. We show here, however, that <span class="hlt">electron</span> holes, once formed, continue to grow, driven by the drift mechanism, and if they remain in the wake may reach a maximum non-linearly stable size, beyond which their uncontrolled growth disrupts the ions. The hole growth calculations provide a quantitative prediction of hole profile and size evolution. Hole growth appears to explain the observations of recent particle-in-cell simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AIPA....6i5028H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AIPA....6i5028H"><span id="translatedtitle">Extraction of ions and <span class="hlt">electrons</span> from audio frequency <span class="hlt">plasma</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>Haleem, N. A.; Abdelrahman, M. M.; Ragheb, M. S.</p> <p>2016-09-01</p> <p>Herein, the extraction of high ion / <span class="hlt">electron</span> current from an audio frequency (AF) nitrogen gas discharge (10 - 100 kHz) is studied and investigated. This system is featured by its small size (L= 20 cm and inner diameter = 3.4 cm) and its capacitive discharge electrodes inside the tube and its high discharge pressure ˜ 0.3 Torr, without the need of high vacuum system or magnetic fields. The extraction system of ion/<span class="hlt">electron</span> current from the <span class="hlt">plasma</span> is a very simple electrode that allows self-beam focusing by adjusting its position from the source exit. The working discharge conditions were applied at a frequency from 10 to 100 kHz, power from 50 - 500 W and the gap distance between the <span class="hlt">plasma</span> meniscus surface and the extractor electrode extending from 3 to 13 mm. The extracted ion/ <span class="hlt">electron</span> current is found mainly dependent on the discharge power, the extraction gap width and the frequency of the audio supply. SIMION 3D program version 7.0 package is used to generate a simulation of ion trajectories as a reference to compare and to optimize the experimental extraction beam from the present audio frequency <span class="hlt">plasma</span> source using identical operational conditions. The focal point as well the beam diameter at the collector area is deduced. The simulations showed a respectable agreement with the experimental results all together provide the optimizing basis of the extraction electrode construction and its parameters for beam production.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/163159','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/163159"><span id="translatedtitle"><span class="hlt">Electron</span> beam control rf discharges for <span class="hlt">plasma</span> processing</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kushner, M.J.; Ruzic, D.N.; Yang, J.</p> <p>1995-12-31</p> <p>Reactive Ion Etching (RIE) discharges for microelectronics fabrication suffer from the inability to separately control <span class="hlt">plasma</span> density and ion power flux to the wafer. Inductively coupled <span class="hlt">plasma</span> (ICP) and <span class="hlt">electron</span> cyclotron resonance (ECR) reactors have been developed to provide some degree of independent control. This is accomplished by arranging for ionization to be provided dominantly by the applied electromagnetic instead of the rf bias to the substrate. Both ICP and ECR reactors, though, optimally operate at low gas pressures, and are not typically used for intermediate to high pressure etching and deposition systems. To address the higher pressure range, a hybrid <span class="hlt">electron</span> beam/RIE discharge system (EB-RIE) has been developed. In the EB-RIE system, a planar <span class="hlt">electron</span> beam (1--3 kV) is injected into the <span class="hlt">plasma</span> chamber above and parallel to the wafer. An rf bias is separately applied to the substrate. A 2-dimensional model of the EB-RIE reactor has been developed to investigate the scaling of the device and analyze previous experimental measurements. Results from the model are discussed for Ar and Ar/SiH{sub 4} gas mixtures in which the beam energy, gas pressure and positioning of the beam are varied.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008EPJD...49..373M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008EPJD...49..373M"><span id="translatedtitle">Solitary wave propagation in quantum <span class="hlt">electron</span>-positron <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>Misra, A. P.; Ghosh, N. K.; Bhowmik, C.</p> <p>2008-10-01</p> <p>Existence of large amplitude stationary solitary wave structures in an unmagnetized <span class="hlt">electron</span>-positron (e-p) <span class="hlt">plasma</span> is studied using a quantum hydrodynamic (QHD) model that includes the quantum force (tunnelling) associated with the Bohm potential and the Fermi-dirac pressure law. It is found that in a quasi-neutral pair (e-p) <span class="hlt">plasma</span>, where the dispersion is only due to the the quantum tunnelling effects, the large amplitude stationary solitary structure exists only when the normalized Mach speed,M <√2. Such solitary structures do not exist in absence of the Bohm potential term in an unmagnetized quasineutral pair (e-p) <span class="hlt">plasma</span>. The system is shown to support only rarefactive stationary solitary waves. For such waves the amplitude, being independent of the quantum parameter H (the ratio of the <span class="hlt">electron</span> plasmon to <span class="hlt">electron</span> Fermi energy), decreases with the Mach number M, whereas the width increases with both M and H. The present theory is applicable to analyze the formation of localized coherent solitary structures at quantum scales in dense astrophysical objects as well as in intense laser fields.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhPl...22h3505W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhPl...22h3505W"><span id="translatedtitle"><span class="hlt">Electron</span> density dependence of impedance probe <span class="hlt">plasma</span> potential measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Walker, D. N.; Blackwell, D. D.; Amatucci, W. E.</p> <p>2015-08-01</p> <p>In earlier works, we used spheres of various sizes as impedance probes in demonstrating a method of determining <span class="hlt">plasma</span> potential, φp, when the probe radius is much larger than the Debye length, λD. The basis of the method in those works [Walker et al., Phys. <span class="hlt">Plasmas</span> 13, 032108 (2006); ibid. 15, 123506 (2008); ibid. 17, 113503 (2010)] relies on applying a small amplitude signal of fixed frequency to a probe in a <span class="hlt">plasma</span> and, through network analyzer-based measurements, determining the complex reflection coefficient, Γ, for varying probe bias, Vb. The frequency range of the applied signal is restricted to avoid sheath resonant effects and ion contributions such that ωpi ≪ ω ≪ ωpe, where ωpi is the ion <span class="hlt">plasma</span> frequency and ωpe is the <span class="hlt">electron</span> <span class="hlt">plasma</span> frequency. For a given frequency and applied bias, both Re(Zac) and Im(Zac) are available from Γ. When Re(Zac) is plotted versus Vb, a minimum predicted by theory occurs at φp [Walker et al., Phys. <span class="hlt">Plasmas</span> 17, 113503 (2010)]. In addition, Im(Zac) appears at, or very near, a maximum at φp. As ne decreases and the sheath expands, the minimum becomes harder to discern. The purpose of this work is to demonstrate that when using network analyzer-based measurements, Γ itself and Im(Zac) and their derivatives are useful as accompanying indicators to Re(Zac) in these difficult cases. We note the difficulties encountered by the most commonly used <span class="hlt">plasma</span> diagnostic, the Langmuir probe. Spherical probe data is mainly used in this work, although we present limited data for a cylinder and a disk. To demonstrate the effect of lowered density as a function of probe geometry, we compare the cylinder and disk using only the indicator Re(Zac).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..121.1219C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..121.1219C"><span id="translatedtitle">Resonant scattering of central <span class="hlt">plasma</span> <span class="hlt">sheet</span> protons by multiband EMIC waves and resultant proton loss timescales</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cao, Xing; Ni, Binbin; Liang, Jun; Xiang, Zheng; Wang, Qi; Shi, Run; Gu, Xudong; Zhou, Chen; Zhao, Zhengyu; Fu, Song; Liu, Jiang</p> <p>2016-02-01</p> <p>This is a companion study to Liang et al. (2014) which reported a "reversed" energy-latitude dispersion pattern of ion precipitation in that the lower energy ion precipitation extends to lower latitudes than the higher-energy ion precipitation. Electromagnetic ion cyclotron (EMIC) waves in the central <span class="hlt">plasma</span> <span class="hlt">sheet</span> (CPS) have been suggested to account for this reversed-type ion precipitation. To further investigate the association, we perform a comprehensive study of pitch angle diffusion rates induced by EMIC wave and the resultant proton loss timescales at L = 8-12 around the midnight. Comparing the proton scattering rates in the Earth's dipole field and a more realistic quiet time geomagnetic field constructed from the Tsyganenko 2001 (T01) model, we find that use of a realistic, nondipolar magnetic field model not only decreases the minimum resonant energies of CPS protons but also considerably decreases the limit of strong diffusion and changes the proton pitch angle diffusion rates. Adoption of the T01 model increases EMIC wave diffusion rates at > ~ 60° equatorial pitch angles but decreases them at small equatorial pitch angles. Pitch angle scattering coefficients of 1-10 keV protons due to H+ band EMIC waves can exceed the strong diffusion rate for both geomagnetic field models. While He+ and O+ band EMIC waves can only scatter tens of keV protons efficiently to cause a fully filled loss cone at L > 10, in the T01 magnetic field they can also cause efficient scattering of ~ keV protons in the strong diffusion limit at L > 10. The resultant proton loss timescales by EMIC waves with a nominal amplitude of 0.2 nT vary from a few hours to several days, depending on the wave band and L shell. Overall, the results demonstrate that H+ band EMIC waves, once present, can act as a major contributor to the scattering loss of a few keV protons at lower L shells in the CPS, accounting for the reversed energy-latitude dispersion pattern of proton precipitation at low</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFMSM14A..06M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFMSM14A..06M"><span id="translatedtitle">Field-line mapping of the near-Earth <span class="hlt">plasma</span> <span class="hlt">sheet</span> based on the <span class="hlt">plasma</span> pressure information obtained by GEOTAIL</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maezawa, K.; Mukai, T.; Saito, Y.</p> <p>2004-12-01</p> <p>The magnetic field line mapping of the magnetotail is a very important issue since physical interpretaion of any correlatinal studies between ionospheric phenomena (e.g. auroral break up) and magnetospheric phenomena (e.g. fast <span class="hlt">plasma</span> flows) is directly affected by the field-line mapping. We here present a unique method to trace field lines from <span class="hlt">plasma</span> measurements in the magnetotail. The <span class="hlt">plasma</span> pressure balance equation tells us that the <span class="hlt">plasma</span> pressure should be constant along the field lines since the JxB force counterbalancing the pressure gradient is perpendicular to the magnetic field. Therefore the contour lines of constant <span class="hlt">plasma</span> pressure in the x-z plane of the magnetotail represent the magentic field lines themselves. Based on this idea, we have analyzed the average <span class="hlt">plasma</span> pressure distribution in the magnetotail using 10 years data from GEOTAIL, for various conditions of solar wind/IMF parameters including IMF Bz polarity. The result indicates a quantitative difference in the latitude-eauatorial distance relationship, i.e., in the degree of stretching of field lines for different polarities of IMF. We emphasize that this is the first time that the large-scale configuration of magnetic field lines is deduced without introducing any model parameters. Our method is also unique in that it is based on <span class="hlt">plasma</span> data only. We will comment on the consistency/inconsistency of our result with the Tyganenko field models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22522273','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22522273"><span id="translatedtitle"><span class="hlt">ELECTRON</span> HEATING IN A RELATIVISTIC, WEIBEL-UNSTABLE <span class="hlt">PLASMA</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kumar, Rahul; Eichler, David; Gedalin, Michael</p> <p>2015-06-20</p> <p>The dynamics of two initially unmagnetized relativistic counter-streaming homogeneous ion–<span class="hlt">electron</span> <span class="hlt">plasma</span> beams are simulated in two dimensions (2D) using the particle-in-cell (PIC) method. It is shown that current filaments, which form due to the Weibel instability, develop a large-scale longitudinal electric field in the direction opposite to the current carried by the filaments as predicted by theory. This field, which is partially inductive and partially electrostatic, is identified as the main source of net <span class="hlt">electron</span> acceleration, greatly exceeding that due to magnetic field decay at later stages. The transverse electric field, although larger than the longitudinal field, is shown to play a smaller role in heating <span class="hlt">electrons</span>, contrary to previous claims. It is found that in one dimension, the <span class="hlt">electrons</span> become strongly magnetized and are not accelerated beyond their initial kinetic energy. Rather, the heating of the <span class="hlt">electrons</span> is enhanced by the bending and break up of the filaments, which releases <span class="hlt">electrons</span> that would otherwise be trapped within a single filament and slow the development of the Weibel instability (i.e., the magnetic field growth) via induction as per Lenz’s law. In 2D simulations, <span class="hlt">electrons</span> are heated to about one quarter of the initial kinetic energy of ions. The magnetic energy at maximum is about 4%, decaying to less than 1% by the end of the simulation. The ions are found to gradually decelerate until the end of the simulation, by which time they retain a residual anisotropy of less than 10%.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..GECHT1003K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..GECHT1003K"><span id="translatedtitle">The Empowerment of <span class="hlt">Plasma</span> Modeling by Fundamental <span class="hlt">Electron</span> Scattering Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kushner, Mark J.</p> <p>2015-09-01</p> <p>Modeling of low temperature <span class="hlt">plasmas</span> addresses at least 3 goals - investigation of fundamental processes, analysis and optimization of current technologies, and prediction of performance of as yet unbuilt systems for new applications. The former modeling may be performed on somewhat idealized systems in simple gases, while the latter will likely address geometrically and electromagnetically intricate systems with complex gas mixtures, and now gases in contact with liquids. The variety of fundamental <span class="hlt">electron</span> and ion scattering data (FSD) required for these activities increases from the former to the latter, while the accuracy required of that data probably decreases. In each case, the fidelity, depth and impact of the modeling depends on the availability of FSD. Modeling is, in fact, empowered by the availability and robustness of FSD. In this talk, examples of the impact of and requirements for FSD in <span class="hlt">plasma</span> modeling will be discussed from each of these three perspectives using results from multidimensional and global models. The fundamental studies will focus on modeling of inductively coupled <span class="hlt">plasmas</span> sustained in Ar/Cl2 where the <span class="hlt">electron</span> scattering from feed gases and their fragments ultimately determine gas temperatures. Examples of the optimization of current technologies will focus on modeling of remote <span class="hlt">plasma</span> etching of Si and Si3N4 in Ar/NF3/N2/O2 mixtures. Modeling of systems as yet unbuilt will address the interaction of atmospheric pressure <span class="hlt">plasmas</span> with liquids Work was supported by the US Dept. of Energy (DE-SC0001939), National Science Foundation (CHE-124752), and the Semiconductor Research Corp.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhPl...23j2504B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhPl...23j2504B"><span id="translatedtitle">A generalized <span class="hlt">plasma</span> dispersion function for <span class="hlt">electron</span> damping in tokamak <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>Berry, L. A.; Jaeger, E. F.; Phillips, C. K.; Lau, C. H.; Bertelli, N.; Green, D. L.</p> <p>2016-10-01</p> <p>Radio frequency wave propagation in finite temperature, magnetized <span class="hlt">plasmas</span> exhibits a wide range of physics phenomena. The <span class="hlt">plasma</span> response is nonlocal in space and time, and numerous modes are possible with the potential for mode conversions and transformations. In addition, diffraction effects are important due to finite wavelength and finite-size wave launchers. Multidimensional simulations are required to describe these phenomena, but even with this complexity, the fundamental <span class="hlt">plasma</span> response is assumed to be the uniform <span class="hlt">plasma</span> response with the assumption that the local <span class="hlt">plasma</span> current for a Fourier mode can be described by the "Stix" conductivity. However, for <span class="hlt">plasmas</span> with non-uniform magnetic fields, the wave vector itself is nonlocal. When resolved into components perpendicular (k⊥) and parallel (k||) to the magnetic field, locality of the parallel component can easily be violated when the wavelength is large. The impact of this inconsistency is that estimates of the wave damping can be incorrect (typically low) due to unresolved resonances. For the case of ion cyclotron damping, this issue has already been addressed by including the effect of parallel magnetic field gradients. In this case, a modified <span class="hlt">plasma</span> response (Z function) allows resonance broadening even when k|| = 0, and this improves the convergence and accuracy of wave simulations. In this paper, we extend this formalism to include <span class="hlt">electron</span> damping and find improved convergence and accuracy for parameters where <span class="hlt">electron</span> damping is dominant, such as high harmonic fast wave heating in the NSTX-U tokamak, and helicon wave launch for off-axis current drive in the DIII-D tokamak.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EL....11535001S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EL....11535001S"><span id="translatedtitle">Acoustic mode driven by fast <span class="hlt">electrons</span> in TJ-II <span class="hlt">Electron</span> Cyclotron Resonance <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>Sun, B. J.; Ochando, M. A.; López-Bruna, D.</p> <p>2016-08-01</p> <p>Intense harmonic oscillations in radiation signals (δ I/I∼ 5{%}) are commonly observed during <span class="hlt">Electron</span> Cyclotron Resonance (ECR) heating in TJ-II stellarator <span class="hlt">plasmas</span> at low line-averaged <span class="hlt">electron</span> density, 0.15 < \\bar{n}e < 0.6 ×1019 \\text{m}-3 . The frequency agrees with acoustic modes. The poloidal modal structure is compatible with Geodesic Acoustic Modes (GAM) but an n \</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PSST...24c4011G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PSST...24c4011G"><span id="translatedtitle">Localized <span class="hlt">electron</span> heating and density peaking in downstream helicon <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>Ghosh, Soumen; Barada, K. K.; Chattopadhyay, P. K.; Ghosh, J.; Bora, D.</p> <p>2015-06-01</p> <p>Localized <span class="hlt">electron</span> temperature and density peaking at different axial locations in the downstream helicon <span class="hlt">plasma</span> have been observed in a linear helicon device with both geometrical and magnetic expansion. The discharge is produced with an m=+1 right helical antenna powered by a RF source operating at 13.56 MHz. Axial wave field measurement shows the presence of damped helicon waves with standing wave character folded into it even at low densities (˜ {{10}16} m-3 ). The measured helicon wavelength is just about twice the antenna length and the phase velocity ≤ft({{v}p}\\right) is almost the speed required for <span class="hlt">electron</span> impact ionization. These experimental observations strongly advocate the Landau damping heating and density production by the helicon waves, particularly in low density <span class="hlt">plasma</span> such as ours. The <span class="hlt">electron</span> temperature maximizes at 35-45 cm away from the antenna center in our experiments indicating a local source of heating at those locations. Different mechanisms responsible for this additional heating at a particular spatial location have been discussed for their possible roles. Further downstream from the location of the maximum <span class="hlt">electron</span> temperature, a density peak located 55-65 cm away from the antenna is observed. This downstream density peaking can be explained through pressure balance in the system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20866340','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20866340"><span id="translatedtitle">Relativistic warm <span class="hlt">plasma</span> theory of nonlinear laser-driven <span class="hlt">electron</span> <span class="hlt">plasma</span> waves.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Schroeder, C B; Esarey, E</p> <p>2010-05-01</p> <p>A relativistic, warm fluid model of a nonequilibrium, collisionless <span class="hlt">plasma</span> is developed and applied to examine nonlinear Langmuir waves excited by relativistically intense, short-pulse lasers. Closure of the covariant fluid theory is obtained via an asymptotic expansion assuming a nonrelativistic <span class="hlt">plasma</span> temperature. The momentum spread is calculated in the presence of an intense laser field and shown to be intrinsically anisotropic. Coupling between the transverse and longitudinal momentum variances is enabled by the laser field. A generalized dispersion relation is derived for Langmuir waves in a thermal <span class="hlt">plasma</span> in the presence of an intense laser field. Including thermal fluctuations in three-velocity-space dimensions, the properties of the nonlinear <span class="hlt">electron</span> <span class="hlt">plasma</span> wave, such as the <span class="hlt">plasma</span> temperature evolution and nonlinear wavelength, are examined and the maximum amplitude of the nonlinear oscillation is derived. The presence of a relativistically intense laser pulse is shown to strongly influence the maximum <span class="hlt">plasma</span> wave amplitude for nonrelativistic phase velocities owing to the coupling between the longitudinal and transverse momentum variances.</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://www.osti.gov/scitech/biblio/22407930','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22407930"><span id="translatedtitle">The behavior of the <span class="hlt">electron</span> <span class="hlt">plasma</span> boundary in ultraintense laser–highly overdense <span class="hlt">plasma</span> interaction</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sánchez-Arriaga, G.; Sanz, J.; Debayle, A.; Lehmann, G.</p> <p>2014-12-15</p> <p>The structural stability of the laser/<span class="hlt">plasma</span> interaction is discussed, for the case of a linearly polarized laser beam interacting with a solid at normal incidence. Using a semi-analytical cold fluid model, the dynamics of the <span class="hlt">electron</span> <span class="hlt">plasma</span> boundary (EPB), usually related to the high-order harmonic generation and laser absorption, are presented. While the well-known J × B <span class="hlt">plasma</span> oscillations at two times the laser frequency are recovered by the model, several other periodic in time stable solutions exist for exactly the same value of the physical parameters. This novel behavior highlights the importance of the laser pulse history among other factors. Some important features, such as the synchronization between the incident laser and the EPB oscillation, depend on the solution under consideration. A description of the possible types of stable oscillations in a parametric plane involving <span class="hlt">plasma</span> density and laser amplitude is presented. The semi-analytical model is compared with particle-in-cell and semi-Lagrangian Vlasov simulations. They show that, among all the stable solutions, the <span class="hlt">plasma</span> preferentially evolves to a state with the EPB oscillating twice faster than the laser. The effect of the <span class="hlt">plasma</span> temperature and the existence of a ramp in the ion density profile are also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/985205','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/985205"><span id="translatedtitle">Relativistic warm <span class="hlt">plasma</span> theory of nonlinear laser-driven <span class="hlt">electron</span> <span class="hlt">plasma</span> waves</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Schroeder, Carl B.; Esarey, Eric</p> <p>2010-06-30</p> <p>A relativistic, warm fluid model of a nonequilibrium, collisionless <span class="hlt">plasma</span> is developed and applied to examine nonlinear Langmuir waves excited by relativistically-intense, short-pulse lasers. Closure of the covariant fluid theory is obtained via an asymptotic expansion assuming a non-relativistic <span class="hlt">plasma</span> temperature. The momentum spread is calculated in the presence of an intense laser field and shown to be intrinsically anisotropic. Coupling between the transverse and longitudinal momentum variances is enabled by the laser field. A generalized dispersion relation is derived for langmuir waves in a thermal <span class="hlt">plasma</span> in the presence of an intense laser field. Including thermal fluctuations in three velocity-space dimensions, the properties of the nonlinear <span class="hlt">electron</span> <span class="hlt">plasma</span> wave, such as the <span class="hlt">plasma</span> temperature evolution and nonlinear wavelength, are examined, and the maximum amplitude of the nonlinear oscillation is derived. The presence of a relativistically intense laser pulse is shown to strongly influence the maximum <span class="hlt">plasma</span> wave amplitude for non-relativistic phase velocities owing to the coupling between the longitudinal and transverse momentum variances.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999PhDT........76D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999PhDT........76D"><span id="translatedtitle">Two dimensional <span class="hlt">electron</span> cyclotron emission imaging study of <span class="hlt">electron</span> temperature profiles and fluctuations in Tokamak <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>Deng, Bihe</p> <p></p> <p>An innovative <span class="hlt">plasma</span> diagnostic technique, <span class="hlt">electron</span> cyclotron emission imaging (ECEI), was successfully developed and implemented on the TEXT-U and RTP tokamaks for the study of <span class="hlt">plasma</span> <span class="hlt">electron</span> temperature profiles and fluctuations. Due to the high spatial and temporal resolution of this new diagnostic, <span class="hlt">plasma</span> filamentation was observed during high power <span class="hlt">electron</span> cyclotron resonance heating (ECRH) in TEXT-U, and was identified as multiple rotating magnetic islands. In RTP, under special <span class="hlt">plasma</span> conditions, evidence for magnetic bubbling was first observed, which is characterized by the flattening of the <span class="hlt">electron</span> temperature and pressure profiles over a small annular region of about 1-2 cm extent near the q = 2 surface. More important results arose from the detailed study of the broadband <span class="hlt">plasma</span> turbulence in TEXT-U and RTP. With the first measurements of poloidal wavenumbers and dispersion relations, turbulent Te fluctuations in the confinement region of TEXT-U <span class="hlt">plasmas</span> were identified as <span class="hlt">electron</span> drift wave turbulence. The fluctuation amplitude is found to follow the mixing length scaling, and the fluctuation-induced conducted- heat flux can account for the observed anomalous energy transport in TEXT-U. In RTP, detailed ECEI study of broadband Te fluctuations has shown that many characteristics of the observed fluctuations are consistent with the predictions of toroidal ηi mode theory. These include the global dependence of the fluctuation frequency and amplitude on the <span class="hlt">plasma</span> density and current. The measured isotope and impurity scalings quantitatively match the predictions of toroidal ηi mode theory. The ECEI measurements in combination with ECRH modification of T e profiles argue against the Te gradients serving as the driving force of the turbulence. With the detailed 2- D measurements of the fluctuation distribution over the <span class="hlt">plasma</span> minor cross-section, large scale, coherent structures similar to the eigenmode structures predicted by toroidal ηi mode theory</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPhCS.653a2006A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPhCS.653a2006A"><span id="translatedtitle">Laser <span class="hlt">electron</span> acceleration in the prepulse produced <span class="hlt">plasma</span> corona</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Andreev, N. E.; Povarnitsyn, M. E.; Pugachev, L. P.; Levashov, P. R.</p> <p>2015-11-01</p> <p>The generation of hot <span class="hlt">electrons</span> at grazing incidence of a subpicosecond relativistic-intense laser pulse onto the plane solid target is analyzed for the parameters of the petawatt class laser systems. We study the preplasma formation on the surface of solid Al target produced by the laser prepulses with different time structure. For modeling of the preplasma dynamics we use a wide-range two-temperature hydrodynamic model. As a result of simulations, the preplasma expansion under the action of the laser prepulse and the <span class="hlt">plasma</span> density profiles for different contrast ratios of the nanosecond pedestal are found. These density profiles were used as the initial density distributions in 3-D PIC simulations of <span class="hlt">electron</span> acceleration by the main P-polarized laser pulse. Results of modeling demonstrate the substantial increase of the characteristic energy and number of accelerated <span class="hlt">electrons</span> for the grazing incidence of a subpicosecond intense laser pulse in comparison with the laser-target interaction at normal incidence.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/212790','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/212790"><span id="translatedtitle">To the problem of <span class="hlt">electron</span> temperature control in <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Galechyan, G.A.; Anna, P.R.</p> <p>1995-12-31</p> <p>One of the main problems in low temperature <span class="hlt">plasma</span> is control <span class="hlt">plasma</span> parameters at fixed values of current and gas pressure in the discharge. It is known that an increase in the intensity of sound wave directed along the positive column to values in excess of a definite threshold leads to essential rise of the temperature of <span class="hlt">electrons</span>. However, no less important is the reduction of <span class="hlt">electron</span> temperature in the discharge down to the value less than that in <span class="hlt">plasma</span> in the absence external influence. It is known that to reduce the <span class="hlt">electron</span> temperature in the <span class="hlt">plasma</span> of CO{sub 2} laser, easily ionizable admixture are usually introduced in the discharge area with the view of increasing the overpopulation. In the present work we shall show that the value of <span class="hlt">electron</span> temperature can be reduced by varying of sound wave intensity at its lower values. The experiment was performed on an experimental setup consisted of the tube with length 52 cm and diameter 9.8 cm, two electrodes placed at the distance of 27 cm from each other. An electrodynamical radiator of sound wave was fastened to one of tube ends. Fastened to the flange at the opposite end was a microphone for the control of sound wave parameters. The studies were performed in range of pressures from 40 to 180 Torr and discharge currents from 40 to 110 mA. The intensity of sound wave was varied from 74 to 92 dB. The measurement made at the first resonance frequency f = 150 Hz of sound in the discharge tube, at which a quarter of wave length keep within the length of the tube. The measurement of longitudinal electric field voltage in <span class="hlt">plasma</span> of positive column was conducted with the help of two probes according to the compensation method. Besides, the measurement of gas temperature in the discharge were taken. Two thermocouple sensors were arranged at the distance of 8 cm from the anode, one of them being installed on the discharge tube axis, the second-fixed the tube wall.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1007180','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1007180"><span id="translatedtitle">Trapped <span class="hlt">Electron</span> Mode Turbulence Driven Intrinsic Rotation in Tokamak <span class="hlt">Plasmas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wang, W. X.; Hahm, T. S.; Ethier, S.; Zakharov, L. E.</p> <p>2011-02-07</p> <p>Recent progress from global gyrokinetic simulations in understanding the origin of intrinsic rotation in toroidal <span class="hlt">plasmas</span> is reported with emphasis on <span class="hlt">electron</span> thermal transport dominated regimes. The turbulence driven intrinsic torque associated with nonlinear residual stress generation by the fluctuation intensity and the intensity gradient in the presence of zonal flow shear induced asymmetry in the parallel wavenumber spectrum is shown to scale close to linearly with <span class="hlt">plasma</span> gradients and the inverse of the <span class="hlt">plasma</span> current. These results qualitatively reproduce empirical scalings of intrinsic rotation observed in various experiments. The origin of current scaling is found to be due to enhanced kll symmetry breaking induced by the increased radial variation of the safety factor as the current decreases. The physics origin for the linear dependence of intrinsic torque on pressure gradient is that both turbulence intensity and the zonal flow shear, which are two key ingredients for driving residual stress, increase with the strength of turbulence drive, which is R0/LTe and R0/Lne for the trapped <span class="hlt">electron</span> mode. __________________________________________________</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920055082&hterms=mechanical+shock&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dmechanical%2Bshock','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920055082&hterms=mechanical+shock&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dmechanical%2Bshock"><span id="translatedtitle">Relativistic, perpendicular shocks in <span class="hlt">electron</span>-positron <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>Gallant, Yves A.; Hoshino, Masahiro; Langdon, A. B.; Arons, Jonathan; Max, Claire E.</p> <p>1992-01-01</p> <p>One-dimensional particle-in-cell <span class="hlt">plasma</span> simulations are used to examine the mechanical structure and thermalization properties of collisionless relativistic shock waves in <span class="hlt">electron</span>-positron <span class="hlt">plasmas</span>. Shocks propagating perpendicularly to the magnetic field direction are considered. It is shown that these shock waves exist, and that they are completely parameterized by the ratio of the upstream Poynting flux to the upstream kinetic energy flux. The way in which the Rankine-Hugoniot shock jump conditions are modified by the presence of wave fluctuations is shown, and they are used to provide a macroscopic description of these collisionless shock flows. The results of a 2D simulation that demonstrates the generality of these results beyond the assumption of the 1D case are discussed. It is suggested that the thermalization mechanism is the formation of a synchrotron maser by the coherently reflected particles in the shock front. Because the downstream medium is thermalized, it is argued that perpendicular shocks in pure <span class="hlt">electron</span>-positron <span class="hlt">plasmas</span> are not candidates as nonthermal particle accelerators.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008APS..APR15HE05S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008APS..APR15HE05S"><span id="translatedtitle">Weibel instability in colliding <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>Silva, Luis</p> <p>2008-04-01</p> <p>The new regimes accessed in ultra intense laser <span class="hlt">plasma</span> interactions and recent developments in relativistic astrophysics are giving rise to an increased interest in the Weibel instability. In fact, whenever colliding streams of <span class="hlt">plasmas</span> (arbitrary mixtures of <span class="hlt">electrons</span>-positrons-ions) are present, a fraction of the kinetic energy of the <span class="hlt">plasma</span> flows can be converted to a sub-equipartition magnetic field. In this talk, and using a combination of particle-in-cell simulations and relativistic kinetic theory, I will first describe the recent theoretical advances in our understanding of the Weibel instability and the connection with the electromagnetic beam <span class="hlt">plasma</span> instability. Emphasis will be given to the coupling with longitudinal modes, leading to the formation of tilted filaments, and to the effects of the collisions and the merging of the Weibel instability with the resistive filamentation instability. In light of these results, the relevance of Weibel instability to ultra intense laser matter interactions (e.g. fast ignition) and to astrophysical scenarios (e.g. in gamma ray bursters and for cluster magnetic fields) will be discussed. Finally, the role of the Weibel instability in the formation of relativistic shocks and in particle acceleration in these structures will also be addressed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10186857','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10186857"><span id="translatedtitle"><span class="hlt">Electron</span> temperature gradient driven instability in the tokamak boundary <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Xu, X.Q.; Rosenbluth, M.N.; Diamond, P.H.</p> <p>1992-12-15</p> <p>A general method is developed for calculating boundary <span class="hlt">plasma</span> fluctuations across a magnetic separatrix in a tokamak with a divertor or a limiter. The slab model, which assumes a periodic <span class="hlt">plasma</span> in the edge reaching the divertor or limiter plate in the scrape-off layer(SOL), should provide a good estimate, if the radial extent of the fluctuation quantities across the separatrix to the edge is small compared to that given by finite particle banana orbit. The Laplace transform is used for solving the initial value problem. The <span class="hlt">electron</span> temperature gradient(ETG) driven instability is found to grow like t{sup {minus}1/2}e{sup {gamma}mt}.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22085965','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22085965"><span id="translatedtitle">Diagnosis of gas temperature, <span class="hlt">electron</span> temperature, and <span class="hlt">electron</span> density in helium atmospheric pressure <span class="hlt">plasma</span> jet</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chang Zhengshi; Zhang Guanjun; Shao Xianjun; Zhang Zenghui</p> <p>2012-07-15</p> <p>The optical emission spectra of helium atmospheric pressure <span class="hlt">plasma</span> jet (APPJ) are captured with a three grating spectrometer. The grating primary spectrum covers the whole wavelength range from 200 nm to 900 nm, with the overlapped grating secondary spectrum appearing from 500 nm to 900 nm, which has a higher resolution than that of the grating primary spectrum. So the grating secondary spectrum of OH (A{sup 2}{Sigma} {sup +}({upsilon} Prime = 0) {yields} X{sup 2}{Pi}({upsilon} Double-Prime = 0)) is employed to calculate the gas temperature (T{sub g}) of helium APPJ. Moreover, the <span class="hlt">electron</span> temperature (T{sub e}) is deduced from the Maxwellian <span class="hlt">electron</span> energy distribution combining with T{sub g}, and the <span class="hlt">electron</span> density (n{sub e}) is extracted from the <span class="hlt">plasma</span> absorbed power. The results are helpful for understanding the physical property of APPJs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015APS..DPPPP2009Y&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015APS..DPPPP2009Y&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Electron</span> Energization During m=0 Magnetic Bursts in MST <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>Young, W. C.; den Hartog, D. J.; Morton, L. A.; MST Team</p> <p>2015-11-01</p> <p>MST reversed-field pinch <span class="hlt">plasmas</span> develop magnetic modes with both a core-resonant poloidal mode m=1 structure and edge-resonant m=0 structure on the reversal surface. The impact of the m=0 modes on <span class="hlt">electron</span> energization has been observed with Thomson scattering under <span class="hlt">plasma</span> conditions with suppressed m=1 modes. Under such conditions, the m=0 modes undergo brief (~100 μs) bursts of localized magnetic activity. These bursts show a localized 4% heating of <span class="hlt">electrons</span> above a 600-900 eV background temperature, associated with a reduction of magnetic energy. An inward propagating cold pulse follows after the heating as a result of reduced confinement. Ensembles of hundreds of bursts are required to measure small relative heating, however single-shot results from MST's high repetition Thomson scattering diagnostic support the ensemble results. Analysis of Thomson scattering data also provides constraints on non-Maxwellian distributions and upcoming upgrades will improve the ability to resolve <span class="hlt">electron</span> currents associated with the magnetic bursts. This work is supported by the US DOE and NSF.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21371250','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21371250"><span id="translatedtitle">Study of <span class="hlt">plasma</span> heating induced by fast <span class="hlt">electrons</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Morace, A.; Batani, D.; Redaelli, R.; Magunov, A.; Fourment, C.; Santos, J. J.; Malka, G.; Boscheron, A.; Nazarov, W.; Vinci, T.; Okano, Y.; Inubushi, Y.; Nishimura, H.; Flacco, A.; Spindloe, C.; Tolley, M.</p> <p>2009-12-15</p> <p>We studied the induced <span class="hlt">plasma</span> heating in three different kinds of targets: mass limited, foam targets, and large mass targets. The experiment was performed at Alise Laser Facility of CEA/CESTA. The laser system emitted a approx1 ps pulse with approx10 J energy at a wavelength of approx1 {mu}m. Mass limited targets had three layers with thicknesses of 10 {mu}m C{sub 8}H{sub 8}, 1 {mu}m C{sub 8}H{sub 7}Cl, and 10 {mu}m C{sub 8}H{sub 8} with size of 100x100 {mu}m{sup 2}. Detailed spectroscopic analysis of x rays emitted from the Cl tracer showed that it was possible to heat up the <span class="hlt">plasma</span> from mass limited targets to a temperature of approx250 eV with density of approx10{sup 21} cm{sup -3}. The <span class="hlt">plasma</span> heating is only produced by fast <span class="hlt">electron</span> transport in the target, being the 10 {mu}m C{sub 8}H{sub 8} overcoating thick enough to prevent any possible direct irradiation of the tracer layer even taking into account mass-ablation due to the prepulse. These results demonstrate that with mass limited targets, it is possible to generate a <span class="hlt">plasma</span> heated up to several hundreds eV. It is also very important for research concerning high energy density phenomena and for fast ignition (in particular for the study of fast <span class="hlt">electrons</span> transport and induced heating).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005PhRvS...8f2001C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005PhRvS...8f2001C"><span id="translatedtitle">Stability of an emittance-dominated <span class="hlt">sheet-electron</span> beam in planar wiggler and periodic permanent magnet structures with natural focusing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carlsten, B. E.; Earley, L. M.; Krawczyk, F. L.; Russell, S. J.; Potter, J. M.; Ferguson, P.; Humphries, S.</p> <p>2005-06-01</p> <p>A <span class="hlt">sheet</span>-beam traveling-wave amplifier has been proposed as a high-power generator of rf from 95 to 300 GHz, using a microfabricated rf slow-wave structure [Carlsten et al., IEEE Trans. <span class="hlt">Plasma</span> Sci. 33, 85 (2005), ITPSBD, 0093-3813, 10.1109/TPS.2004.841172], for emerging radar and communications applications. The planar geometry of microfabrication technologies matches well with the nearly planar geometry of a <span class="hlt">sheet</span> beam, and the greater allowable beam current leads to high-peak power, high-average power, and wide bandwidths. Simulations of nominal designs using a vane-loaded waveguide as the slow-wave structure have indicated gains in excess of 1 dB/mm, with extraction efficiencies greater than 20% at 95 GHz with a 120-kV, 20-A <span class="hlt">electron</span> beam. We have identified stable <span class="hlt">sheet</span>-beam formation and transport as the key enabling technology for this type of device. In this paper, we describe <span class="hlt">sheet</span>-beam transport, for both wiggler and periodic permanent magnet (PPM) magnetic field configurations, with natural (or single-plane) focusing. For emittance-dominated transport, the transverse equation of motion reduces to a Mathieu equation, and to a modified Mathieu equation for a space-charge dominated beam. The space-charge dominated beam has less beam envelope ripple than an emittance-dominated beam, but they have similar stability thresholds (defined by where the beam ripple continues to grow without bound along the transport line), consistent with the threshold predicted by the Mathieu equation. Design limits are derived for an emittance-dominated beam based on the Mathieu stability threshold. The increased beam envelope ripple for emittance-dominated transport may impact these design limits, for some transport requirements. The stability of transport in a wiggler field is additionally compromised by the beam’s increased transverse motion. Stable <span class="hlt">sheet</span>-beam transport with natural focusing is shown to be achievable for a 120-kV, 20-A, elliptical beam with a cross section of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhPl...23g2106D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhPl...23g2106D"><span id="translatedtitle">Impurity effects on trapped <span class="hlt">electron</span> mode in tokamak <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>Du, Huarong; Wang, Zheng-Xiong; Dong, J. Q.</p> <p>2016-07-01</p> <p>The effects of impurity ions on the trapped <span class="hlt">electron</span> mode (TEM) in tokamak <span class="hlt">plasmas</span> are numerically investigated with the gyrokinetic integral eigenmode equation. It is shown that in the case of large <span class="hlt">electron</span> temperature gradient ( η e ), the impurity ions have stabilizing effects on the TEM, regardless of peaking directions of their density profiles for all normalized <span class="hlt">electron</span> density gradient R / L n e . Here, R is the major radius and L n e is the <span class="hlt">electron</span> density gradient scale length. In the case of intermediate and/or small η e , the light impurity ions with conventional inwardly (outwardly) peaked density profiles have stabilizing effects on the TEM for large (small) R / L n e , while the light impurity ions with steep inwardly (outwardly) peaked density profiles can destabilize the TEM for small (large) R / L n e . Besides, the TEM driven by density gradient is stabilized (destabilized) by the light carbon or oxygen ions with inwardly (outwardly) peaked density profiles. In particular, for flat and/or moderate R / L n e , two independent unstable modes, corresponding respectively to the TEM and impurity mode, are found to coexist in <span class="hlt">plasmas</span> with impurity ions of outwardly peaked density profiles. The high Z tungsten impurity ions play a stronger stabilizing role in the TEM than the low Z impurity ions (such as carbon and oxygen) do. In addition, the effects of magnetic shear and collision on the TEM instability are analyzed. It is shown that the collisionality considered in this work weakens the trapped <span class="hlt">electron</span> response, leading to a more stable TEM instability, and that the stabilizing effects of the negative magnetic shear on the TEM are more significant when the impurity ions with outwardly peaked density profile are taken into account.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E2123Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E2123Y"><span id="translatedtitle">Nonlinear <span class="hlt">plasma</span> processes and the formation of <span class="hlt">electron</span> kappa distribution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yoon, Peter</p> <p>2016-07-01</p> <p>The goal of nonequilibrium statistical mechanics is to establish fundamental relationship between the time irreversible macroscopic dynamics and the underlying time reversible behavior of microscopic system. The paradigm of achieving this seemingly paradoxical goal is through the concept of probability. For classical systems Boltzmann accomplished this through his H theorem and his kinetic equation for dilute gas. Boltzmann's H function is the same as classical extensive entropy aside from the minus sign, and his kinetic equation is applicable for short-range molecular interaction. For <span class="hlt">plasmas</span>, the long-range electromagnetic force dictates the inter-particular interaction, and the underlying entropy is expected to exhibit non-extensive, or non-additive behavior. Among potential models for the non-additive entropy, the celebrated Tsallis entropy is the most well known. One of the most useful fundamental kinetic equations that governs the long-range <span class="hlt">plasma</span> interaction is that of weak turbulence kinetic theory. At present, however, there is no clear-cut connection between the Tsallis entropy and the kinetic equations that govern <span class="hlt">plasma</span> behavior. This can be contrasted to Boltzmann's H theorem, which is built upon his kinetic equation. The best one can do is to show that the consequences of Tsallis entropy and <span class="hlt">plasma</span> kinetic equation are the same, that is, they both imply kappa distribution. This presentation will overview the physics of <span class="hlt">electron</span> acceleration by beam-generated Langmuir turbulence, and discuss the asymptotic solution that rigorously can be shown to correspond to the kappa distribution. Such a finding is a strong evidence, if not water-tight proof, that there must be profound inter-relatioship between the Tsallis thermostatistical theory and the <span class="hlt">plasma</span> kinetic theory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhPl...23e3104Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhPl...23e3104Z"><span id="translatedtitle"><span class="hlt">Plasma</span> and cyclotron frequency effects on output power of the <span class="hlt">plasma</span> wave-pumped free-<span class="hlt">electron</span> lasers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zolghadr, S. H.; Jafari, S.; Raghavi, A.</p> <p>2016-05-01</p> <p>Significant progress has been made employing <span class="hlt">plasmas</span> in the free-<span class="hlt">electron</span> lasers (FELs) interaction region. In this regard, we study the output power and saturation length of the <span class="hlt">plasma</span> whistler wave-pumped FEL in a magnetized <span class="hlt">plasma</span> channel. The small wavelength of the whistler wave (in sub-μm range) in <span class="hlt">plasma</span> allows obtaining higher radiation frequency than conventional wiggler FELs. This configuration has a higher tunability by adjusting the <span class="hlt">plasma</span> density relative to the conventional ones. A set of coupled nonlinear differential equations is employed which governs on the self-consistent evolution of an electromagnetic wave. The <span class="hlt">electron</span> bunching process of the whistler-pumped FEL has been investigated numerically. The result reveals that for a long wiggler length, the bunching factor can appreciably change as the <span class="hlt">electron</span> beam propagates through the wiggler. The effects of <span class="hlt">plasma</span> frequency (or <span class="hlt">plasma</span> density) and cyclotron frequency on the output power and saturation length have been studied. Simulation results indicate that with increasing the <span class="hlt">plasma</span> frequency, the power increases and the saturation length decreases. In addition, when density of background <span class="hlt">plasma</span> is higher than the <span class="hlt">electron</span> beam density (i.e., for a dense <span class="hlt">plasma</span> channel), the <span class="hlt">plasma</span> effects are more pronounced and the FEL-power is significantly high. It is also found that with increasing the strength of the external magnetic field frequency, the power decreases and the saturation length increases, noticeably.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/334290','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/334290"><span id="translatedtitle"><span class="hlt">Plasma</span> and ion barrier for <span class="hlt">electron</span> beam spot stability</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kwan, T.J.T.; Snell, C.M.</p> <p>1999-04-01</p> <p>The concept of a self-biased target to spatially confine the ions generated by the bombardment of intense <span class="hlt">electron</span> beams on bremsstrahlung conversion targets has been predicted by computer simulation and further verified by experiments at the Integrated Test Stand for DARHT at Los Alamos National Laboratory. This technical article reports an alternative method of containing the <span class="hlt">plasmas</span> and ions from the bremsstrahlung conversion target if the energy density of the <span class="hlt">electron</span> beam is below a certain threshold. With the proposed changes of the <span class="hlt">electron</span> beam parameters of the second axis of DARHT, the authors are able to show that a thin (0.5 mm) metallic barrier such as pure beryllium, or boron carbide with desirable thermal properties, is sufficiently transparent to the 20 MeV DARHT beam and at the same time able to confine the ions between the target and the barrier foil. The temperature rise in the foil due to energy deposited by the <span class="hlt">electron</span> beam is expected to be below the melting point of the materials for the first three pulses. More important, they have shown in their time dependent particle-in-cell simulations that the deployment of a barrier situated 1 to 2 cm away from the converter target can achieve the ion confinement needed for the stability of the <span class="hlt">electron</span> beam spot.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22218638','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22218638"><span id="translatedtitle"><span class="hlt">Electron</span> beam driven lower hybrid waves in a dusty <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Prakash, Ved; Vijayshri; Sharma, Suresh C.; Gupta, Ruby</p> <p>2013-05-15</p> <p>An <span class="hlt">electron</span> beam propagating through a magnetized dusty <span class="hlt">plasma</span> drives electrostatic lower hybrid waves to instability via Cerenkov interaction. A dispersion relation and the growth rate of the instability for this process have been derived taking into account the dust charge fluctuations. The frequency and the growth rate of the unstable wave increase with the relative density of negatively charged dust grains. Moreover, the growth rate of the instability increases with beam density and scales as the one-third power of the beam density. In addition, the dependence of the growth rate on the beam velocity is also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22047559','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22047559"><span id="translatedtitle">Probe measurements of the <span class="hlt">electron</span> distribution function in an <span class="hlt">electron</span>-beam-produced ytterbium <span class="hlt">plasma</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bobrova, A. A.; Dubinov, A. E.; Esin, M. I.; Zolotov, S. V.; Maksimov, A. N.; Selemir, V. D.; Sidorov, I. I.; Shubin, A. Yu.</p> <p>2011-01-15</p> <p>A nonequilibrium anisotropic <span class="hlt">plasma</span> produced by an <span class="hlt">electron</span> beam in the residual air with a low content of ytterbium vapor was investigated by the probe method. It is found that a minor (at a level of a few ppm) admixture of ytterbium to low-pressure air substantially modifies the <span class="hlt">electron</span> energy distribution function (EEDF): the main peak corresponding to thermal <span class="hlt">electrons</span> broadens, and new peaks appear. It is shown that the observed change in the EEDF is caused by the low ionization energy of ytterbium, due to which one beam <span class="hlt">electron</span> can ionize several ytterbium atoms. The new peaks in the EEDF correspond to the final energies of a beam <span class="hlt">electron</span> after each subsequent ionizing collision with ytterbium atoms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110005665','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110005665"><span id="translatedtitle">Modeling of the Convection and Interaction of Ring Current, Plasmaspheric and <span class="hlt">Plasma</span> <span class="hlt">Sheet</span> <span class="hlt">Plasmas</span> in the Inner Magnetosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fok, Mei-Ching; Chen, Sheng-Hsien; Buzulukova, Natalia; Glocer, Alex</p> <p>2010-01-01</p> <p>Distinctive sources of ions reside in the plasmasphere, plasmasheet, and ring current regions at discrete energies constitute the major <span class="hlt">plasma</span> populations in the inner/middle magnetosphere. They contribute to the electrodynamics of the ionosphere-magnetosphere system as important carriers of the global current system, in triggering; geomagnetic storm and substorms, as well as critical components of <span class="hlt">plasma</span> instabilities such as reconnection and Kelvin-Helmholtz instability at the magnetospheric boundaries. Our preliminary analysis of in-situ measurements shoves the complexity of the <span class="hlt">plasmas</span> pitch angle distributions at particularly the cold and warm <span class="hlt">plasmas</span>, vary dramatically at different local times and radial distances from the Earth in response to changes in solar wind condition and Dst index. Using an MHD-ring current coupled code, we model the convection and interaction of cold, warm and energetic ions of plasmaspheric, plasmasheet, and ring current origins in the inner magnetosphere. We compare our simulation results with in-situ and remotely sensed measurements from recent instrumentation on Geotail, Cluster, THEMIS, and TWINS spacecraft.</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. Their policies may differ from this site.</small> </div> </center> <div id="footer-wrapper"> <div class="footer-content"> <div id="footerOSTI" class=""> <div class="row"> <div class="col-md-4 text-center col-md-push-4 footer-content-center"><small><a href="http://www.science.gov/disclaimer.html">Privacy and Security</a></small> <div class="visible-sm visible-xs push_footer"></div> </div> <div class="col-md-4 text-center col-md-pull-4 footer-content-left"> <img src="https://www.osti.gov/images/DOE_SC31.png" alt="U.S. Department of Energy" usemap="#doe" height="31" width="177"><map style="display:none;" name="doe" id="doe"><area shape="rect" coords="1,3,107,30" href="http://www.energy.gov" alt="U.S. Deparment of Energy"><area shape="rect" coords="114,3,165,30" href="http://www.science.energy.gov" alt="Office of Science"></map> <a ref="http://www.osti.gov" style="margin-left: 15px;"><img src="https://www.osti.gov/images/footerimages/ostigov53.png" alt="Office of Scientific and Technical Information" height="31" width="53"></a> <div class="visible-sm visible-xs push_footer"></div> </div> <div class="col-md-4 text-center footer-content-right"> <a href="http://www.osti.gov/nle"><img src="https://www.osti.gov/images/footerimages/NLElogo31.png" alt="National Library of Energy" height="31" width="79"></a> <a href="http://www.science.gov"><img src="https://www.osti.gov/images/footerimages/scigov77.png" alt="science.gov" height="31" width="98"></a> <a href="http://worldwidescience.org"><img src="https://www.osti.gov/images/footerimages/wws82.png" alt="WorldWideScience.org" height="31" width="90"></a> </div> </div> </div> </div> </div> <p><br></p> </div><!-- container --> </body> </html>