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Sample records for substorm growth phase

  1. Physics of Substorm Growth Phase, Onset, and Dipolarization

    SciTech Connect

    C.Z. Cheng

    2003-10-22

    A new scenario of substorm growth phase, onset, and depolarization during expansion phase and the corresponding physical processes are presented. During the growth phase, as a result of enhanced plasma convection, the plasma pressure and its gradient are continued to be enhanced over the quiet-time values in the plasma sheet. Toward the late growth phase, a strong cross-tail current sheet is formed in the near-Earth plasma sheet region, where a local magnetic well is formed, the plasma beta can reach a local maximum with value larger than 50 and the cross-tail current density can be enhanced to over 10nA/m{sup 2} as obtained from 3D quasi-static magnetospheric equilibrium solutions for the growth phase. The most unstable kinetic ballooning instabilities (KBI) are expected to be located in the tailward side of the strong cross-tail current sheet region. The field lines in the most unstable KBI region map to the transition region between the region-1 and region-2 currents in the ionosphere, which is consistent with the observed initial brightening location of the breakup arc in the intense proton precipitation region. The KBI explains the AMPTE/CCE observations that a low-frequency instability with a wave period of 50-75 seconds is excited about 2-3 minutes prior to substorm onset and grows exponentially to a large amplitude at the onset of current disruption (or current reduction). At the current disruption onset higher frequency instabilities are excited so that the plasma and electromagnetic field fluctuations form a strong turbulent state. Plasma transport takes place due to the strong turbulence to relax the ambient plasma pressure profile so that the plasma pressure and current density are reduced and the ambient magnetic field intensity increases by more than a factor of 2 in the high-beta(sub)eq region and the field line geometry recovers from tail-like to dipole-like dipolarization.

  2. Magnetotail and Ionospheric Evolution during the Substorm Growth Phase

    NASA Astrophysics Data System (ADS)

    Hsieh, M.; Otto, A.

    2013-12-01

    The growth phase of geomagnetic substorms is characterized by the equatorward motion of the growth phase arc close to or even into the region of diffuse aurora characteristic for a dipolar magnetic field. The presented results use a model of current sheet thinning based on midnight magnetic flux depletion (MMFD) in the near-Earth tail which is caused by sunward convection to replenish magnetic flux that is eroded on the dayside by magnetic reconnection during periods of southward IMF. The results use a three-dimensional mesocale MHD simulation of the near-Earth tail. This paper examines the changes of the near-Earth magnetotail region mapped into the ionopshere. Of specific interest are the changes in magnetic flux, flux tube entropy, field-aligned currents, convection, and the size and location of the respective ionospheric footprints of the magnetotail structure and properties. The mapping method is based on the Tsyganenko [1996] magnetic field model combined with magnetic flux conservation. It is found that the mapped magnetotail properties move equatorward by about 2 to 3 degrees during the growth phase. The removal of magnetic flux in the near-Earth tail causes a contraction of the ionospheric footprints of this tail region such that all of the mapped magnetotail structures move equatorward. The thin current is mapped into the region where magnetic flux is strongly depleted, and in close proximity with strong and narrow region 1 and 2 sense field-aligned currents. Our ionospheric maps also show a sharp transition between the dipole and stretched magnetic field and an evolution of thinning and convergent motion of field-aligned currents in the late growth phase.

  3. Increases in plasma sheet temperature with solar wind driving during substorm growth phases.

    PubMed

    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

    2014-12-28

    During substorm growth phases, magnetic reconnection at the magnetopause extracts ∼10(15) J from the solar wind which is then stored in the magnetotail lobes. Plasma sheet pressure increases to balance magnetic flux density increases in the lobes. Here we examine plasma sheet pressure, density, and temperature during substorm growth phases using 9 years of Cluster data (>316,000 data points). We show that plasma sheet 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 plasma sheet temperature before onset and the minimum SuperMAG AL (SML) auroral index in the subsequent substorm. We discuss how energization of the plasma sheet before onset may result from thermodynamically adiabatic processes; how hotter plasma sheets may result in magnetotail instabilities, and how this relates to the onset and size of the subsequent substorm expansion phase.

  4. Increases in plasma sheet temperature with solar wind driving during substorm growth phases

    PubMed Central

    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

    2014-01-01

    During substorm growth phases, magnetic reconnection at the magnetopause extracts ∼1015 J from the solar wind which is then stored in the magnetotail lobes. Plasma sheet pressure increases to balance magnetic flux density increases in the lobes. Here we examine plasma sheet pressure, density, and temperature during substorm growth phases using 9 years of Cluster data (>316,000 data points). We show that plasma sheet 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 plasma sheet temperature before onset and the minimum SuperMAG AL (SML) auroral index in the subsequent substorm. We discuss how energization of the plasma sheet before onset may result from thermodynamically adiabatic processes; how hotter plasma sheets may result in magnetotail instabilities, and how this relates to the onset and size of the subsequent substorm expansion phase. PMID:26074645

  5. Particle scattering and current sheet stability in the geomagnetic tail during the substorm growth phase

    NASA Technical Reports Server (NTRS)

    Pulkkinen, T. I.; Baker, D. N.; Pellinen, R. J.; Buechner, J.; Koskinen, H. E. J.; Lopez, R. E.; Dyson, R. L.; Frank, L. A.

    1992-01-01

    The particle scattering and current sheet stability features in the geomagnetic tail during the phase of substorm growth were investigated using Tsyganenko's (1989) magnetic field model. In a study of four substorm events which were observed both in the high-altitude nightside tail and in the auroral ionosphere, the model magnetic field was adjusted to each case so as to represent the global field development during the growth phase of the substorms. The model results suggest that the auroral brightenings are connected with processes taking place in the near-earth region inside about 15 earth radii. The results also suggest that there is a connection between the chaotization of the electrons and the auroral brightenings at substorm onset.

  6. What the Polar Cap Tells Us about the Substorm Growth Phase

    NASA Technical Reports Server (NTRS)

    Brittnacher, M. J.; Fillingim, M. O.; Chua, D.; Wilber, M.; Parks, G. K.; Germany, G. A.; Spann, James F., Jr.

    1998-01-01

    The polar cap region in the 30 to 60 minute period prior to the onset of the auroral substorm has been examined using global images from the Polar Ultraviolet Imager (UVI) to look for observational evidence of processes related to the substorm growth phase. In particular, the area of the polar cap has been measured to determine changes in its size in relation to the orientation of the interplanetary magnetic field (IMF). It was found that the size of the polar cap region increases during the growth phase even if the IMF has no southward component. Three phenomena have been observed to produce the increase in the size of the polar cap: (1) motion of the auroral oval to lower latitude, (2) thinning of the auroral oval, and (3) reduction of intense auroral precipitation in the polar cap region. The first phenomenon has been considered to be a result of the growth of the tail lobe magnetic field and the second is related to the thinning of the plasma sheet. Both of these have been supported by in situ observational evidence and are consistent with current models of substorm development. However, the third phenomenon appears to be unrelated to the first two and does not appear to be the result of opening of the polar cap flux tubes to the solar wind IMF. This reduction of auroral precipitation provides evidence of a growth phase process, or change in auroral precipitation processes, that is not explained by current substorm models.

  7. Global Observation of Substorm Growth Phase Processes in the Polar Caps

    NASA Technical Reports Server (NTRS)

    Brittnacher, M.; OFillingim, M. O.; Chua, D.; Wilber, M.; Parks, G. K.; Germany, G. A.; Spann, J. F.

    1998-01-01

    Global images of the polar cap region during the substorm growth phase by the Polar Ultraviolet Imager reveals evidence of the processes which are not completely explained by current models. In particular, it was found that size of the polar cap region increases during the growth phase even if the interplanetary magnetic field has no southward component. Three phenomena were observed to produce an increase in the size of the polar cap: (1) motion of the auroral oval to lower latitude, (2) thinning of the auroral oval, and (3) reduction of intense aurora[ precipitation in the polar region. Correlation of image intensities with in situ particle measurements from the FAST satellite are being conducted to study the three growth phase phenomena; and to help identify the source regions of the particles, the mechanisms involved in producing the auroral structures and what may be reducing the polar cap precipitation during the substorm growth phase.

  8. Current carriers in the near-earth cross-tail current sheet during substorm growth phase

    NASA Technical Reports Server (NTRS)

    Mitchell, D. G.; Williams, D. J.; Huang, C. Y.; Frank, L. A.; Russell, C. T.

    1990-01-01

    Throughout most of the growth phase of a substorm, the cross-tail current at x about -10 Re can be supplied by the curvature drift of a bi-directional field aligned distribution of 1 keV electrons. Just prior to its local disruption after substorm onset, the cross-tail current in the now thin (about 400 km) current sheet is carried by the cross-tail serpentine motion of non-adiabatic ions (Speiser, 1965). The instability of this latter current leads to the local disruption of the near-earth current sheet.

  9. A Double-Disruption Substorm Model - The Growth Phase

    NASA Astrophysics Data System (ADS)

    Sofko, G. J.; McWilliams, K. A.; Hussey, G. C.

    2014-12-01

    sufficiently that the NSh reaches the outer radiation belt at about t=85 min, the ionospheric conductivity has grown sufficiently that the XTJ disrupted by the DZs changes its dawn-to-dusk closure by travelling through the ionosphere. This second stage of disruption is the Substorm Current Wedge (SCW). Onset follows at about t=88 min.

  10. Quasi-static evolution of the magnetosphere: The substorm growth phase

    NASA Astrophysics Data System (ADS)

    Kropotkin, A. P.; Lui, A. T. Y.

    1995-09-01

    The growth phase of a substorm is marked by ``energy loading'' in the magnetosphere prior to energy dissipation in the substorm expansion phase. This loading takes place primarily in the geomagnetic tail and is identified by the growth of total magnetic flux in the tail lobes, the increase of magnetic field intensity in the near-Earth portion of the tail, and the field line stretching leading to thinning of the plasma sheet in that region where a ``neck'' is thus formed. The last two processes are shown here to be natural consequences of the magnetic flux accumulation by considering theoretically a quasi-static evolution of tail equilibrium. One of the model inferences in the growth phase is a strong diminishment of the dimension of the transition region in the nightside where field lines change from dipolar to tail-like. This accounts for the growth phase development often seen in the near-synchronous region. This study also reveals a qualitative difference between the growth phase and the ``quiet'' condition or the ``ground state:'' the tail lobe flux should exceed a certain threshold for the neck formation to occur and the size of the transition region to diminish.

  11. Growth-phase thinning of the near-Earth current sheet during the CDAW 6 substorm

    NASA Technical Reports Server (NTRS)

    Sanny, Jeff; Mcpherron, R. L.; Russell, C. T.; Baker, D. N.; Pulkkinen, T. I.; Nishida, A.

    1994-01-01

    The thinning of the near-Earth current sheet during the growth phase of the Coordinated Data Analysis Workshop (CDAW) 6 magnetospheric substorm is studied. The expansion onset of the substorm occurred at 1054 UT, March 22, 1979. During the growth phase, two spacecraft, International Sun Earth Explorer (ISEE) 1 and ISEE 2, were within the current sheet approximately 13 R(sub E) from the Earth and obtained simultaneous high-resolution magnetic data at two points in the current sheet. Plasma data were also provided by the ISEE spacecraft and solar wind data by IMP 8. To facilitate the analysis, the GSM magnetic field data are transformed to a 'neutral sheet coordinate system' in which the new x axis is parallel to the average magnetic field above and below the neutral sheet and the new y axis lies in the GSM equatorial plane. A model based on the assumption that the current sheet is a time-invariant structure fails to predict neutral sheet crossing times. Consequently, the Harris sheet model, which allows one to remove the restriction of time invariancy, is used instead. It is found that during the growth phase, a model parameter corresponding to the thickness of the current sheet decreased exponentially from about 5 R(sub E) to 1 R(sub E) with a time constant of about 14 min. In addition, the ISEE 1 and ISEE 2 neutral sheet crossings after expansion onset indicate that the neutral sheet was moving upward at 7 km/s relative to the spacecraft. Since both crossings occurred in approximately 80 s, the current sheet thickness is estimated to be about 500 km. These results demonstrate that the near-Earth current sheet undergoes dramatic thinning during the substorm growth phase and expansion onset.

  12. Near-earth Thin Current Sheets and Birkeland Currents during Substorm Growth Phase

    SciTech Connect

    Sorin Zaharia; C.Z. Cheng

    2003-04-30

    Two important phenomena observed during the magnetospheric substorm growth phase are modeled: the formation of a near-Earth (|X| {approx} 9 R{sub E}) thin cross-tail current sheet, as well as the equatorward shift of the ionospheric Birkeland currents. Our study is performed by solving the 3-D force-balance equation with realistic boundary conditions and pressure distributions. The results show a cross-tail current sheet with large current (J{sub {phi}} {approx} 10 nA/m{sup 2}) and very high plasma {beta} ({beta} {approx} 40) between 7 and 10 R{sub E}. The obtained region-1 and region-2 Birkeland currents, formed on closed field lines due to pressure gradients, move equatorward and become more intense (J{sub {parallel}max} {approx} 3 {micro}A/m{sup 2}) compared to quiet times. Both results are in agreement with substorm growth phase observations. Our results also predict that the cross-tail current sheet maps into the ionosphere in the transition region between the region-1 and region-2 currents.

  13. CURRENT SHEET THINNING AND ENTROPY CONSTRAINTS DURING THE SUBSTORM GROWTH PHASE

    NASA Astrophysics Data System (ADS)

    Otto, A.; Hall, F., IV

    2009-12-01

    A typical property during the growth phase of geomagnetic substorms is the thinning of the near-Earth current sheet, most pronounced in the region between 6 and 15 R_E. We propose that the cause for the current sheet thinning is convection from the midnight tail region to the dayside to replenish magnetospheric magnetic flux which is eroded at the dayside as a result of dayside reconnection. Adiabatic convection from the near-Earth tail region toward the dayside must conserve the entropy on magnetic field lines. This constraint prohibits a source of the magnetic flux from a region further out in the magnetotail. Thus the near-Earth tail region is increasingly depleted of magnetic flux (the Erickson and Wolf [1980] problem) with entropy matching that of flux tubes that are eroded on the dayside. It is proposed that the magnetic flux depletion in the near-Earth tail forces the formation of thin current layers. The process is documented by three-dimensional MHD simulations. It is shown that the simulations yield a time scale, location, and other general characteristics of the current sheet evolution during the substorm growth phase.

  14. Convection Constraints and Current Sheet Thinning During the Substorm Growth Phase

    NASA Astrophysics Data System (ADS)

    Otto, A.; Hsieh, M.

    2012-12-01

    A typical property during the growth phase of geomagnetic substorms is the thinning of the near-Earth current sheet, most pronounced in the region between 6 and 15 RE. We propose that the cause for this current sheet thinning is convection from the midnight tail region to the dayside to replenish magnetospheric magnetic flux that is eroded at the dayside as a result of dayside reconnection. Slow (adiabatic) convection from the near-Earth tail region toward the dayside must conserve the entropy on magnetic field lines. This constraint prohibits a source of magnetic flux from a region further out in the magnetotail. Thus the near-Earth tail region is increasingly depleted of magnetic flux (the Erickson and Wolf [1980] problem) with entropy matching that of flux tubes that are eroded on the dayside. It is proposed that the magnetic flux depletion in the near-Earth tail forces the formation of thin current layers. The process is illustrated and examined by three-dimensional meso-scale MHD simulations. It is shown that the simulations yield a time scale, location, and other general characteristics of the current sheet evolution consistent with observations during the substorm growth phase. The developing thin current sheet is easily destabilized and can undergo localized reconnection events. We present properties of the thinning current sheet, the associated entropy evolution, examples of localized reconnection onset and we discuss the dependence of this process on external parameters such the global reconnection rate.

  15. On the origin of plasma sheet reconfiguration during the substorm growth phase

    NASA Astrophysics Data System (ADS)

    Gordeev, Evgeny; Sergeev, Victor; Merkin, Viacheslav; Kuznetsova, Maria

    2017-09-01

    Recently, Hsieh and Otto (2014) suggested that transport of the closed magnetic flux to the dayside reconnection region may be a key process which controls the reconfiguration of magnetotail during the substorm growth phase. We investigate this problem using global self-consistent MHD simulations and confirm that magnetotail reconfiguration is essentially a 3-D process which cannot be fully described based on 2-D-like tail evolution powered by the magnetic flux loading into the lobes. We found that near-Earth return convection strength on the nightside is directly related to the intensity of dayside reconnection, which causes the formation of antisunward azimuthal pressure gradients that force plasma to flow toward the dayside magnetopause. This near-Earth part of global convection develops immediately after the onset of dayside reconnection and reaches a quasi-steady level in 10-15 min. Its magnitude exceeds the total sunward flux transport in the midtail plasma sheet at X≈-20RE by an order of magnitude, causing significant amount (0.1-0.2 GWb) of closed magnetic flux to be removed from the near-Earth plasma sheet during moderate substorm. In that region the Bz depletion and current sheet thinning are closely related to each other, and the local Jy(Bz) relationship in the simulations matches reasonably well the power law expression found in the plasma sheet. In summary, global simulations confirm quantitatively that near-Earth return convection is primarily responsible for the severe depletion of the closed magnetic flux in the plasma sheet, major tail stretching, and current sheet thinning in the near magnetotail at r < 15RE.

  16. Formation of a very thin current sheet in the near-earth magnetotail and the explosive growth phase of substorms

    NASA Technical Reports Server (NTRS)

    Lee, L. C.; Zhang, L.; Choe, G. S.; Cai, H. J.

    1995-01-01

    A magnetofricional method is used to construct two-dimensional MHD equilibria of the Earth's magnetosphere for a given distribution of entropy functions(S = pV(exp gamma), where p is the plasma pressure and V is the tube volume per unit magnetic flux. It is found that a very thin current sheet with B (sub zeta) is less than 0.5 nu T and thickness less than 1000 km can be formed in the near-earth magnetotail (x is approximately -8 to -20R(sub e) during the growth phase of substorm. The tail current sheets are found to become thinner as the entropy or the entropy gradient increases. It is suggested that the new entropy anti-diffusion instability associated with plasma transport across field lines leads to magnetic field dipolarization and accelerates the formation of thin current sheet, which may explain the observed explosive growth phase of substorms.

  17. On the formation and origin of substorm growth phase/onset auroral arcs inferred from conjugate space-ground observations

    NASA Astrophysics Data System (ADS)

    Motoba, T.; Ohtani, S.; Anderson, B. J.; Korth, H.; Mitchell, D. G.; Lanzerotti, L. J.; Shiokawa, K.; Connors, M. G.; Kletzing, C.; Reeves, G. D.

    2015-12-01

    Magnetotail processes and structures related to substorm growth phase/onset auroral arcs remain poorly understood mostly due to the lack of adequate observations. In this study we make a comparison between ground-based optical measurements of the premidnight growth phase/onset arcs at subauroral latitudes and magnetically conjugate measurements made by the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) at ~780 km in altitude and by the Van Allen Probe-B spacecraft crossing L values of ~5.0-5.6 in the premidnight inner tail region. The conjugate observations offer a unique opportunity to examine the detailed features of the arc location relative to large-scale Birkeland currents and of the magnetospheric counterpart. The observations strongly suggest that the premidnight arc is connected to highly localized pressure gradients embedded in the near-tail R2 source region via a local upward FAC.

  18. Substorms

    NASA Astrophysics Data System (ADS)

    Haerendel, Gerhard

    2015-01-01

    This chapter deals with the essence of the magnetospheric substorm, the return of magnetic flux into the magnetosphere after disconnection from the solar wind magnetic field. There are three fundamental transport processes involved: (1) thinning of the tail plasma sheet and accompanying recession of the outer boundary of the dipolar magnetosphere during the growth phase, (2) flux transport along the tail toward that boundary after onset of tail reconnection, and (3) penetration of plasma and magnetic flux into the dipolar magnetosphere. The chapter then looks at corresponding processes in the Jupiter and Saturn magnetospheres and tails, which are strongly dominated by the fast planetary rotations. It elucidates some key aspects of the entry problem, albeit from a personal vantage point, and addresses the still open questions. Finally, the chapter addresses the correlation between solar wind ram pressure and auroral activity and brightness on Jupiter and Saturn.

  19. On the formation and origin of substorm growth phase/onset auroral arcs inferred from conjugate space-ground observations

    DOE PAGES

    Motoba, T.; Ohtani, S.; Anderson, B. J.; ...

    2015-10-27

    In this study, magnetotail processes and structures related to substorm growth phase/onset auroral arcs remain poorly understood mostly due to the lack of adequate observations. In this study we make a comparison between ground-based optical measurements of the premidnight growth phase/onset arcs at subauroral latitudes and magnetically conjugate measurements made by the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) at ~780 km in altitude and by the Van Allen Probe B (RBSP-B) spacecraft crossing L values of ~5.0–5.6 in the premidnight inner tail region. The conjugate observations offer a unique opportunity to examine the detailed features of the arcmore » location relative to large-scale Birkeland currents and of the magnetospheric counterpart. Our main findings include (1) at the early stage of the growth phase the quiet auroral arc emerged ~4.3° equatorward of the boundary between the downward Region 2 (R2) and upward Region 1 (R1) currents; (2) shortly before the auroral breakup (poleward auroral expansion) the latitudinal separation between the arc and the R1/R2 demarcation narrowed to ~1.0°; (3) RBSP-B observed a magnetic field signature of a local upward field-aligned current (FAC) connecting the arc with the near-Earth tail when the spacecraft footprint was very close to the arc; and (4) the upward FAC signature was located on the tailward side of a local plasma pressure increase confined near L ~5.2–5.4. These findings strongly suggest that the premidnight arc is connected to highly localized pressure gradients embedded in the near-tail R2 source region via the local upward FAC.« less

  20. On the formation and origin of substorm growth phase/onset auroral arcs inferred from conjugate space-ground observations

    SciTech Connect

    Motoba, T.; Ohtani, S.; Anderson, B. J.; Korth, H.; Mitchell, D.; Lanzerotti, L. J.; Shiokawa, K.; Connors, M.; Kletzing, C. A.; Reeves, G. D.

    2015-10-27

    In this study, magnetotail processes and structures related to substorm growth phase/onset auroral arcs remain poorly understood mostly due to the lack of adequate observations. In this study we make a comparison between ground-based optical measurements of the premidnight growth phase/onset arcs at subauroral latitudes and magnetically conjugate measurements made by the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) at ~780 km in altitude and by the Van Allen Probe B (RBSP-B) spacecraft crossing L values of ~5.0–5.6 in the premidnight inner tail region. The conjugate observations offer a unique opportunity to examine the detailed features of the arc location relative to large-scale Birkeland currents and of the magnetospheric counterpart. Our main findings include (1) at the early stage of the growth phase the quiet auroral arc emerged ~4.3° equatorward of the boundary between the downward Region 2 (R2) and upward Region 1 (R1) currents; (2) shortly before the auroral breakup (poleward auroral expansion) the latitudinal separation between the arc and the R1/R2 demarcation narrowed to ~1.0°; (3) RBSP-B observed a magnetic field signature of a local upward field-aligned current (FAC) connecting the arc with the near-Earth tail when the spacecraft footprint was very close to the arc; and (4) the upward FAC signature was located on the tailward side of a local plasma pressure increase confined near L ~5.2–5.4. These findings strongly suggest that the premidnight arc is connected to highly localized pressure gradients embedded in the near-tail R2 source region via the local upward FAC.

  1. On the formation and origin of substorm growth phase/onset auroral arcs inferred from conjugate space-ground observations

    NASA Astrophysics Data System (ADS)

    Motoba, T.; Ohtani, S.; Anderson, B. J.; Korth, H.; Mitchell, D.; Lanzerotti, L. J.; Shiokawa, K.; Connors, M.; Kletzing, C. A.; Reeves, G. D.

    2015-10-01

    Magnetotail processes and structures related to substorm growth phase/onset auroral arcs remain poorly understood mostly due to the lack of adequate observations. In this study we make a comparison between ground-based optical measurements of the premidnight growth phase/onset arcs at subauroral latitudes and magnetically conjugate measurements made by the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) at ~780 km in altitude and by the Van Allen Probe B (RBSP-B) spacecraft crossing L values of ~5.0-5.6 in the premidnight inner tail region. The conjugate observations offer a unique opportunity to examine the detailed features of the arc location relative to large-scale Birkeland currents and of the magnetospheric counterpart. Our main findings include (1) at the early stage of the growth phase the quiet auroral arc emerged ~4.3° equatorward of the boundary between the downward Region 2 (R2) and upward Region 1 (R1) currents; (2) shortly before the auroral breakup (poleward auroral expansion) the latitudinal separation between the arc and the R1/R2 demarcation narrowed to ~1.0°; (3) RBSP-B observed a magnetic field signature of a local upward field-aligned current (FAC) connecting the arc with the near-Earth tail when the spacecraft footprint was very close to the arc; and (4) the upward FAC signature was located on the tailward side of a local plasma pressure increase confined near L ~5.2-5.4. These findings strongly suggest that the premidnight arc is connected to highly localized pressure gradients embedded in the near-tail R2 source region via the local upward FAC.

  2. Form the end of substorm growth phase till the first 1-2 minutes of onset: Evidence of a transitional stage in optical auroral and in-situ observations

    NASA Astrophysics Data System (ADS)

    Liang, J.; Zhu, P.; Donovan, E.; Saito, M.

    2016-12-01

    A classical scenario of auroral substorm usaully involves a quiescent preexisting arc during the growth phase and a significant brightening and poleward expansion of auroras characteristic of the substorm expansion phase. However, optical auroral observations repeatedly reveal that there is often a 1-2 minute transitional stage between the quiescent growth-phase arc and the significant auroral expansion. Such a transitional stage is characterized by a gradual intensification and in many cases the emergence of azimuthally-spaced structures, aka the "auroral beads", along the preexisting arc. The auroral beads usually feature well-defined e-growth rate in optical intensity. Despite the beading and moderate intensification the arc shape is essentially maintained for the first minute of onset, until it is deformed by a violent poleward expansion of substorm auroras which marks the full expansion phase of the substorm. In this study, we investigate a number of onset auroral beading events with conjugate observations from THEMIS probes, with focus on potential magnetospheric signatures of the transitional stage in in-situ data. These signatures typically consist of magnetic field/pressure perturbations that gradually grow in magnitude but are nevertheless limited as compared to those in the subsequent large-scale dipolarization/current disruption. The wave period of the perturbation is found to roughly conform to w kyvy , in which w is the frequency of perturbation, ky is the azimuthal wavenumber inferred from the separation of auroral beads, and vy is the azimuthal flow velocity. The perturbations detected on azimuthally separated probes are different in phase. Those potential clues of the transitional stage in in-situ observations occur concurrently with or slightly precede the initial auroral brightening and beading seen in optical data. We find evidence of such a transitional stage in substorm onset events with and without preceding fast earthward flows. The above

  3. PC index and magnetic substorms

    NASA Astrophysics Data System (ADS)

    Troshichev, Oleg; Janzhura, Alexander; Sormakov, Dmitry; Podorozhkina, Nataly

    PC index is regarded as a proxy of the solar wind energy that entered into the magnetosphere as distinct from the AL and Dst indices, which are regarded as characteristics of the energy that realize in the magnetosphere in form of substorm and magnetic storms. This conclusion is based on results of analysis of relationships between the polar cap magnetic activity (PC-index) and parameters of the solar wind, on the one hand, relationships between changes of PC and development of magnetospheric substorms (AL-index) and magnetic storms (Dst-index), on the other hand. This paper describes in detail the following main results which demonstrate a strong connection between the behavior of PC and development of magnetic disturbances in the auroral zone: (1) magnetic substorms are preceded by the РС index growth (isolated and extended substorms) or long period of stationary PC (postponed substorms), (2) the substorm sudden onsets are definitely related to such PC signatures as leap and reverse, which are indicative of sharp increase of the PC growth rate, (3) substorms generally start to develop when the PC index exceeds the threshold level ~ 1.5±0.5 mV/m, irrespective of the substorm growth phase duration and type of substorm, (4) linear dependency of AL values on PC is typical of all substorm events irrespective of type and intensity of substorm.

  4. Poleward leaping auroras, the substorm expansive and recovery phases and the recovery of the plasma sheet

    SciTech Connect

    Hones, E.W.

    1992-05-01

    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 plasma sheet. 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 plasma sheet, observed on many occasions, suggests a causal relationship between substorm maximum epoch and recovery phase on the one hand and plasma sheet recovery on the other.

  5. Is energy storage and release part of the substorm process?

    NASA Technical Reports Server (NTRS)

    Clauer, C. R.

    1981-01-01

    Models for magnetospheric substorms were considered. A modified model which includes the growth phase, a time interval prior to the onset of the expansion phase, during which energy was transferred from a solar wind to the magnetosphere and stored for subsequent release, is discussed. Evidence for energy storage in the tail prior to substorm expansion for both isolated and moderate substorm activity is reviewed.

  6. Auroral substorms

    NASA Astrophysics Data System (ADS)

    Heikkila, Walter J.

    Many models of the substorm process assume a uniform current sheet before the auroral breakup and the onset of the expansion phase; in fact, a lower energy state for the cross-tail current is a set of filamentary currents. We hypothesize that such filaments are connected to auroral arcs during the growth phase. We must have an arc for it to break up, an essential part of the substorm. This means that we should look at instabilities of current filaments in the magnetotail. We have proposed that the appropriate instability is a simple meander of the current filament in the equatorial plane. An outward meander will be caused by the current carriers, undergoing curvature drift, becoming demagnetized. We take the inductive electric field as EIND = -∂A/∂t, using the Coulomb or transverse gauge. This inductive electric field will in general have a component parallel to the magnetic field. We take the response of the plasma to be reflected in a scalar potential, EES = - ∇ φ that response must be such as to diminish the actual (or net) E∥ Part of the response is the formation of field-aligned currents producing the well-known substorm current diversion. At the same time the plasma will enhance the transverse component of the induction electric field. Other work has indicated that a substorm reconnection X-line will form. The enhanced induction electric field near the emerging X-line will cause a discharge, again to decrease E∥ After subsequent betatron acceleration even zero energy particles can be energized to MeV energies in a matter of seconds in a two-step process. A plasmoid will be created which will move in the direction of least magnetic pressure, namely tailward.

  7. Investigation of isolated substorms: Generation conditions and characteristics of different phases

    NASA Astrophysics Data System (ADS)

    Vorobjev, V. G.; Yagodkina, O. I.; Zverev, V. L.

    2016-11-01

    Characteristics of isolated substorms selected by variations in the 1-min values of the AL index are analyzed. The substorms were divided into several types with respect to the behavior of the Bz component of the interplanetary magnetic field (IMF) during the expansion phase. The probability of observations of substorms associated with the northward turn of the Bz component of IMF was 19%, while the substorms taking place at Bz < 0 were observed in 53% of cases. A substantial number of events in which no substorm magnetic activity was observed in the auroral zone after a long (>30 min) period of the southward IMF and a following sharp turn of the Bz component of IMF before the north was detected. The data suggest that a northward IMF turn is neither a necessary nor sufficient condition for generating substorms. It has been shown for substorms of the both types that the average duration of the southward IMF to moment T 0 and the average intensity of the magnetic perturbation in the maximum are approximately the same and amount to 80 min and-650 nT, respectively. However, for substorms at Bz < 0, their mean duration, including the expansive and recovery phases, is on average 30 min longer than that at a northward turn of IMF. Correlations between the loading-unloading processes in the magnetosphere in the periods of magnetospheric substorms were investigated with different functions that determine the efficiency of the energy transfer from the solar wind to the magnetosphere. It has been shown that the highest correlation coefficient ( r = 0.84) is observed when the function suggested by Newell et al. (2007) is used. It has been detected that a simple function VB S yields a high correlation coefficient ( r = 0.75).

  8. Contributions of substorm injections to SYM-H depressions in the main phase of storms

    NASA Astrophysics Data System (ADS)

    He, Zhaohai; Dai, Lei; Wang, Chi; Duan, Suping; Zhang, Lingqian; Chen, Tao; Roth, I.

    2016-12-01

    Substorm injections bring energetic particles to the inner magnetosphere. But the role of the injected population in building up the storm time ring current is not well understood. By surveying Los Alamos National Laboratory geosynchronous data during 34 storm main phases, we show evidence that at least some substorm injections can contribute to substorm-time scale SYM-H/Dst depressions in the main phase of storms. For event studies, we analyze two typical events in which the main-phase SYM-H index exhibited stepwise depressions that are correlated with particle flux enhancement due to injections and with AL index. A statistical study is performed based on 95 storm time injection events. The flux increases of the injected population (50-400 keV) are found proportional to the sharp SYM-H depressions during the injection interval. By identifying dispersionless and dispersive injection signals, we estimate the azimuthal extent of the substorm injection. Statistical results show that the injection regions of these storm time substorms are characterized with an azimuthal extent larger than 06:00 magnetic local time. These results suggest that at least some substorm injections may mimic the large-scale enhanced convection and contribute to sharp decreases of Dst in the storm main phase.

  9. Traveling compression region observed in the mid-tail lobes near substorm expansion phase onset

    NASA Technical Reports Server (NTRS)

    Taguchi, S.; Slavin, J. A.; Lepping, R. P.; Nose, M.

    1996-01-01

    The characteristics of traveling compression regions (TCRs) in the midtail lobes are examined. Through the use of the AL index, isolated substorm events with well developed expansion phases are selected. The TCR events which feature a field compression coincident with modified Bz variations are categorized into different types, and the magnetic variations are interpreted in terms of the relative location of the point of observation to the plasmoid at the time of release and the effects of tail flaring. In order to understand the relationship between the plasmoid release time and the substorm onset time, the time difference between the different types of TCR and the substorm onset determined by Pi 2 pulsations at mid-latitude ground stations, is examined. The results suggest that the downtail release of most of the plasmoids created earthwards of -38 earth radii occurs at almost the same distance as the substorm onset.

  10. Traveling compression region observed in the mid-tail lobes near substorm expansion phase onset

    NASA Technical Reports Server (NTRS)

    Taguchi, S.; Slavin, J. A.; Lepping, R. P.; Nose, M.

    1996-01-01

    The characteristics of traveling compression regions (TCRs) in the midtail lobes are examined. Through the use of the AL index, isolated substorm events with well developed expansion phases are selected. The TCR events which feature a field compression coincident with modified Bz variations are categorized into different types, and the magnetic variations are interpreted in terms of the relative location of the point of observation to the plasmoid at the time of release and the effects of tail flaring. In order to understand the relationship between the plasmoid release time and the substorm onset time, the time difference between the different types of TCR and the substorm onset determined by Pi 2 pulsations at mid-latitude ground stations, is examined. The results suggest that the downtail release of most of the plasmoids created earthwards of -38 earth radii occurs at almost the same distance as the substorm onset.

  11. Poleward leaping auroras, the substorm expansive and recovery phases and the recovery of the plasma sheet

    SciTech Connect

    Hones, E.W.

    1992-01-01

    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 plasma sheet. 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 plasma sheet, observed on many occasions, suggests a causal relationship between substorm maximum epoch and recovery phase on the one hand and plasma sheet recovery on the other.

  12. Substorm evolution of auroral structures

    NASA Astrophysics Data System (ADS)

    Partamies, N.; Juusola, L.; Whiter, D.; Kauristie, K.

    2015-07-01

    Auroral arcs are often associated with magnetically quiet time and substorm growth phases. We have studied the evolution of auroral structures during global and local magnetic activity to investigate the occurrence rate of auroral arcs during different levels of magnetic activity. The ground-magnetic and auroral conditions are described by the magnetometer and auroral camera data from five Magnetometers — Ionospheric radars — All-sky cameras Large Experiment stations in Finnish and Swedish Lapland. We identified substorm growth, expansion, and recovery phases from the local electrojet index (IL) in 1996-2007 and analyzed the auroral structures during the different phases. Auroral structures were also analyzed during different global magnetic activity levels, as described by the planetary Kp index. The distribution of auroral structures for all substorm phases and Kp levels is of similar shape. About one third of all detected structures are auroral arcs. This suggests that auroral arcs occur in all conditions as the main element of the aurora. The most arc-dominated substorm phases occur in the premidnight sector, while the least arc-dominated substorm phases take place in the dawn sector. Arc event lifetimes and expectation times calculated for different substorm phases show that the longest arc-dominated periods are found during growth phases, while the longest arc waiting times occur during expansion phases. Most of the arc events end when arcs evolve to more complex structures. This is true for all substorm phases. Based on the number of images of auroral arcs and the durations of substorm phases, we conclude that a randomly selected auroral arc most likely belongs to a substorm expansion phase. A small time delay, of the order of a minute, is observed between the magnetic signature of the substorm onset (i.e., the beginning of the negative bay) and the auroral breakup (i.e., the growth phase arc changing into a dynamic display). The magnetic onset was

  13. Identification of critical substorm-expansion-phase phenomena: Problems addressable with GEM observations

    SciTech Connect

    Lyons, L.R.

    1994-09-01

    Understanding the physics of the substorm process is currently a crucial topic in magnetospheric physics. Fundamental to this understanding is the determination of what phenomena occur in the magnetosphere during the expansion phase, where these phenomena occur, and how they propagate during the expansion phase. Satellite observations have given researchers important point measurements of what happens; however there is potential for enhancing the use of ground-based observations to study the substorm phenomena. Such enhanced use of ground-based measurements is already taking place as part of the GEM (Geospace Environment Modeling) boundary-layer campaign and is planned to continue throughout the tail/substorm campaign. This report identifies expansion-phase phenomena observed locally within the nightside magnetosphere and from the ground, believed to be of fundamental importance for understanding large-scale substorm processes. The phenomena observed in situ are related to the phenomena observed from the ground. The primary goal is to identify outstanding questions that could be addressed during the GEM tail/substorm campaign using ground-based data from GEM observing periods in coordination with available satellite observations.

  14. Near-earth substorm onset: A coordinated study

    SciTech Connect

    Persson, M.A.L.; Opgenoorth, H.J.; Eriksson, A.I.; Dovner, P.O.; Pulkkinen, T.I.; Reeves, G.D.; Belian, R.D.; Andre, M.; Blomberg, L.G.; Erlandson, R.E.

    1994-08-15

    The authors present simultaneous satellite and ground-based measurements of a substorm. Throughout the initial substorm expansion, southward drifting arcs are observed poleward of the expanding substorm aurora, indicating two independent systems of particle precipitation. Freja passes the brightening onset arc in the topside ionosphere near the moment of the substorm onset, observing an Alfven wave, field aligned current and oxygen ion outflow. The substorm onset occurs at low magnetospheric L-shells, near the poleward edge of the region of trapped particles. The location and time for the substorm injection are confirmed by geostationary spacecraft together with magnetometers, all-sky cameras and radar on the ground. The authors believe that the substorm onset may be triggered by modification of the oxygen content of the inner magnetosphere during the growth-phase caused by ionospheric ion outflow. 15 refs., 7 figs.

  15. Modeling substorm dynamics of the magnetosphere: from self-organization and self-organized criticality to nonequilibrium phase transitions.

    PubMed

    Sitnov, M I; Sharma, A S; Papadopoulos, K; Vassiliadis, D

    2002-01-01

    Earth's magnetosphere during substorms exhibits a number of characteristic features such as the signatures of low effective dimension, hysteresis, and power-law spectra of fluctuations on different scales. The largest substorm phenomena are in reasonable agreement with low-dimensional magnetospheric models and in particular those of inverse bifurcation. However, deviations from the low-dimensional picture are also quite considerable, making the nonequilibrium phase transition more appropriate as a dynamical analog of the substorm activity. On the other hand, the multiscale magnetospheric dynamics cannot be limited to the features of self-organized criticality (SOC), which is based on a class of mathematical analogs of sandpiles. Like real sandpiles, during substorms the magnetosphere demonstrates features, that are distinct from SOC and are closer to those of conventional phase transitions. While the multiscale substorm activity resembles second-order phase transitions, the largest substorm avalanches are shown to reveal the features of first-order nonequilibrium transitions including hysteresis phenomena and a global structure of the type of a temperature-pressure-density diagram. Moreover, this diagram allows one to find a critical exponent, that reflects the multiscale aspect of the substorm activity, different from the power-law frequency and scale spectra of autonomous systems, although quite consistent with second-order phase transitions. In contrast to SOC exponents, this exponent relates input and output parameters of the magnetosphere. Using an analogy to the dynamical Ising model in the mean-field approximation, we show the connection between the data-derived exponent of nonequilibrium transitions in the magnetosphere and the standard critical exponent beta of equilibrium second-order phase transitions.

  16. Magnetospheric Substorm Electrodynamics

    NASA Technical Reports Server (NTRS)

    Lyons, L. R.

    1998-01-01

    It was proposed that the expansion phase of substorms results from a reduction in the large-scale electric field imparted to the magnetosphere from the solar wind, following a greater than or equal to 30 min growth phase due to an enhancement in this electric field. The reduction in the electric field is assumed to propagate anti-sunward within the magnetosphere. Triggering by a reduction in the electric field is suggested by the observation that substorms are often triggered by northward turning of the interplanetary magnetic field (IMF). However, under the theory presented here, substorms may be triggered by anything that causes an electric field reduction such as a reduction in the magnitude of the y-component of the IMF. A reduction in the large-scale electric field disrupts both the inward motion and energization of plasma sheet particles that occurs during the growth phase. It is suggested here that this can lead to formation of the expansion-phase current wedge and active aurora. The current wedge results from the magnetic drift of ions, which has a speed proportional to particle energy, and a large azimuthal gradient in mean particle energy that is expected to develop in the vicinity of magnetic midnight during the growth phase. Current wedge formation will most likely be initiated near the radial distance (approx. 6- 10 R(sub E)) of the peak in the growth-phase plasma pressure distribution, and then propagate tailward from that region. Order-of-magnitude calculations show that the above proposal can account for the rapid development of the expansion phase relative to the growth phase, the magnitude of the reduction in the cross-tail current within the current wedge, the speeds of tailward and westward expansion of the current reduction region, the speeds of poleward and westward motion of active aurora in the ionosphere, and the magnitude of wedge field-aligned currents that connect the ionospheric region of active auroral to the divergent cross

  17. Lower thermospheric wind variations in auroral patches during the substorm recovery phase

    NASA Astrophysics Data System (ADS)

    Oyama, Shin-ichiro; Shiokawa, Kazuo; Miyoshi, Yoshizumi; Hosokawa, Keisuke; Watkins, Brenton J.; Kurihara, Junichi; Tsuda, Takuo T.; Fallen, Christopher T.

    2016-04-01

    Measurements of the lower thermospheric wind with a Fabry-Perot interferometer (FPI) at Tromsø, Norway, found the largest wind variations in a night during the appearance of auroral patches at the substorm recovery phase. Taking into account magnetospheric substorm evolution of plasma energy accumulation and release, the largest wind amplitude at the recovery phase is a fascinating result. The results are the first detailed investigation of the magnetosphere-ionosphere-thermosphere coupled system at the substorm recovery phase using comprehensive data sets of solar wind, geomagnetic field, auroral pattern, and FPI-derived wind. This study used three events in November 2010 and January 2012, particularly focusing on the wind signatures associated with the auroral morphology, and found three specific features: (1) wind fluctuations that were isolated at the edge and/or in the darker area of an auroral patch with the largest vertical amplitude up to about 20 m/s and with the longest oscillation period about 10 min, (2) when the convection electric field was smaller than 15 mV/m, and (3) wind fluctuations that were accompanied by pulsating aurora. This approach suggests that the energy dissipation to produce the wind fluctuations is localized in the auroral pattern. Effects of the altitudinal variation in the volume emission rate were investigated to evaluate the instrumental artifact due to vertical wind shear. The small electric field values suggest weak contributions of the Joule heating and Lorentz force processes in wind fluctuations. Other unknown mechanisms may play a principal role at the recovery phase.

  18. Statistical properties of substorm auroral onset beads/rays

    NASA Astrophysics Data System (ADS)

    Nishimura, Y.; Yang, J.; Pritchett, P. L.; Coroniti, F. V.; Donovan, E. F.; Lyons, L. R.; Wolf, R. A.; Angelopoulos, V.; Mende, S. B.

    2016-09-01

    Auroral substorms are often associated with optical ray or bead structures during initial brightening (substorm auroral onset waves). Occurrence probabilities and properties of substorm onset waves have been characterized using 112 substorm events identified in Time History of Events and Macroscale Interactions during Substorms (THEMIS) all-sky imager data and compared to Rice Convection Model-Equilibrium (RCM-E) and kinetic instability properties. All substorm onsets were found to be associated with optical waves, and thus, optical waves are a common feature of substorm onset. Eastward propagating wave events are more frequent than westward propagating wave events and tend to occur during lower-latitude substorms (stronger solar wind driving). The wave propagation directions are organized by orientation of initial brightening arcs. We also identified notable differences in wave propagation speed, wavelength (wave number), period, and duration between westward and eastward propagating waves. In contrast, the wave growth rate does not depend on the propagation direction or substorm strength but is inversely proportional to the wave duration. This suggests that the waves evolve to poleward expansion at a certain intensity threshold and that the wave properties do not directly relate to substorm strengths. However, waves are still important for mediating the transition between the substorm growth phase and poleward expansion. The relation to arc orientation can be explained by magnetotail structures in the RCM-E, indicating that substorm onset location relative to the pressure peak determines the wave propagation direction. The measured wave properties agree well with kinetic ballooning interchange instability, while cross-field current instability and electromagnetic ion cyclotron instability give much larger propagation speed and smaller wave period.

  19. Tests of Substorm Models' Predictions Using ISTP Observations

    NASA Technical Reports Server (NTRS)

    Sanchez, Ennio R.

    1998-01-01

    This report provides progress to test the predictions of substorm models using ISTP observations. During the first year, two investigations were initiated in collaboration with a number of ISTP researchers. Both investigations use a combination of simultaneous measurements from high-, low-, and ground-altitude instruments to: (1) explore the role of MHD resonances in the onset and evolution of substorms, and (2) establish the timing of events in the magnetosphere and ionosphere during the substorm evolution beginning with the growth phase and ending with the recovery phase.

  20. Theory of substorm onset and dipolarization

    NASA Astrophysics Data System (ADS)

    Cheng, C. Z.; Zaharia, S.

    2003-04-01

    We present a theory of substorm onset and dipolarization. At the end of the substorm growth phase, the plasma pressure profile steepens and a thin current sheet is formed in the near-Earth plasma sheet around the local midnight with a finite radial and azimuthal domain. In the current sheet the plasma beta becomes about 50 or larger and magnetic field curvature is enhanced, and the kinetic ballooning instability (KBI) is excited with amplitude localized at the maximum plasma beta region. The KBI explains the low frequency (about 1 min period) instability observed by AMPTE/CCE with period on the order of 1 min is observed about 2-3 minutes before the substorm onset [Cheng and Lui, GRL, 1998]. The KBI is responsible for substorm onset because as it grows to a large amplitude with Δ B/B > 01, it causes an enhanced westward ion drift during the explosive growth phase that lasts about 30 sec. The KBI then excites higher frequency instabilities, and the plasma and magnetic field become strongly turbulent. The plasma transport in both radial and azimuthal direction caused by the turbulence relaxes the steep plasma pressure profile during the expansion phase. As the plasma pressure profile relaxes, the magnetic field configuration dipolarizes and returns to the pre-substorm more dipole-like geometry. Theories of current sheet formation, KBI mechanism and dipolarization will be presented along with numerical solutions of 3D magnetospheric structure.

  1. Energetic electron precipitation and auroral morphology at the substorm recovery phase

    NASA Astrophysics Data System (ADS)

    Oyama, S.; Kero, A.; Rodger, C. J.; Clilverd, M. A.; Miyoshi, Y.; Partamies, N.; Turunen, E.; Raita, T.; Verronen, P. T.; Saito, S.

    2017-06-01

    It is well known that auroral patterns at the substorm recovery phase are characterized by diffuse or patch structures with intensity pulsation. According to satellite measurements and simulation studies, the precipitating electrons associated with these aurorae can reach or exceed energies of a few hundreds of keV through resonant wave-particle interactions in the magnetosphere. However, because of difficulty of simultaneous measurements, the dependency of energetic electron precipitation (EEP) on auroral morphological changes in the mesoscale has not been investigated to date. In order to study this dependency, we have analyzed data from the European Incoherent Scatter (EISCAT) radar, the Kilpisjärvi Atmospheric Imaging Receiver Array (KAIRA) riometer, collocated cameras, ground-based magnetometers, the Van Allen Probe satellites, Polar Operational Environmental Satellites (POES), and the Antarctic-Arctic Radiation-belt (Dynamic) Deposition-VLF Atmospheric Research Konsortium (AARDDVARK). Here we undertake a detailed examination of two case studies. The selected two events suggest that the highest energy of EEP on those days occurred with auroral patch formation from postmidnight to dawn, coinciding with the substorm onset at local midnight. Measurements of the EISCAT radar showed ionization as low as 65 km altitude, corresponding to EEP with energies of about 500 keV.Plain Language SummaryAurora is emission of the atmospheric particles excited by electrons coming from the magnetosphere. The electrons have energies of 1-10 keV or higher. In particular, it is known that the energy can increase more than 100 keV in association with the pulsating aurora and that morphology of the pulsating aurora changes with time. However, relationships between the energy increase and the morphological change have not been studied well. This study analyzed the ionospheric density and auroral images and found that significant increases</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM14B..05S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM14B..05S"><span>MESSENGER Observations of <span class="hlt">Substorm</span> Activity at Mercury</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, W. J.; Slavin, J. A.; Fu, S.; Raines, J. M.; Zong, Q. G.; Poh, G.; Jia, X.; Sundberg, T.; Gershman, D. J.; Pu, Z.; Zurbuchen, T.; Shi, Q.</p> <p>2015-12-01</p> <p>MErcury Surface, Space ENviroment, GEochemistry, and Ranging (MESSENGER) magnetic field and plasma measurements taken during crossings of Mercury's magnetotail from 2011 to 2014 have been investigated for <span class="hlt">substorms</span>. A number of events with clear Earth-like <span class="hlt">growth</span> <span class="hlt">phase</span> and expansion <span class="hlt">phase</span> signatures were found. The thinning of the plasma sheet and the increase of magnetic field intensity in the lobe were observed during the <span class="hlt">growth</span> <span class="hlt">phase</span> and plasma sheet was observed to thicken during the expansion <span class="hlt">phase</span>, which are similar to the observations at Earth. But the time scale of Mercury's <span class="hlt">substorm</span> is only several minutes comparing with the several hours at Earth [Sun et al., 2015a]. Detailed analysis of magnetic field fluctuations during the <span class="hlt">substorm</span> expansion <span class="hlt">phase</span> have revealed low frequency plasma waves, e.g. Pi2-like pulsations. The By fluctuations accompanying <span class="hlt">substorm</span> dipolarizations are consistent with pulses of field-aligned currents near the high latitude edge of the plasma sheet. Further study shows that they are near-circularly polarized electromagnetic waves, most likely Alfvén waves. Soon afterwards the plasma sheet thickened and MESSENGER detected a series of compressional waves. We have also discussed their possible sources [Sun et al., 2015b]. Sun, W.-J., J. A. Slavin, S. Y. Fu, et al. (2015a), MESSENGER observations of magnetospheric <span class="hlt">substorm</span> activity in Mercury's near magnetotail. Geophys. Res. Lett., 42, 3692-3699. doi: 10.1002/2015GL064052.Sun, W.-J., J. A. Slavin, S. Y. Fu, et al. (2015b), MESSENGER observations of Alfvénic and compressional waves during Mercury's <span class="hlt">substorms</span>. Geophys. Res. Lett., 42, in press. doi: 10.1002/ 2015GL065452.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..122.2973B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..122.2973B"><span><span class="hlt">Substorm</span> occurrence rates, <span class="hlt">substorm</span> recurrence times, and solar wind structure</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Borovsky, Joseph E.; Yakymenko, Kateryna</p> <p>2017-03-01</p> <p>Two collections of <span class="hlt">substorms</span> are created: 28,464 <span class="hlt">substorms</span> identified with jumps in the SuperMAG AL index in the years 1979-2015 and 16,025 <span class="hlt">substorms</span> identified with electron injections into geosynchronous orbit in the years 1989-2007. <span class="hlt">Substorm</span> occurrence rates and <span class="hlt">substorm</span> recurrence-time distributions are examined as functions of the <span class="hlt">phase</span> of the solar cycle, the season of the year, the Russell-McPherron favorability, the type of solar wind plasma at Earth, the geomagnetic-activity level, and as functions of various solar and solar wind properties. Three populations of <span class="hlt">substorm</span> occurrences are seen: (1) quasiperiodically occurring <span class="hlt">substorms</span> with recurrence times (waiting times) of 2-4 h, (2) randomly occurring <span class="hlt">substorms</span> with recurrence times of about 6-15 h, and (3) long intervals wherein no <span class="hlt">substorms</span> occur. A working model is suggested wherein (1) the period of periodic <span class="hlt">substorms</span> is set by the magnetosphere with variations in the actual recurrence times caused by the need for a solar wind driving interval to occur, (2) the mesoscale structure of the solar wind magnetic field triggers the occurrence of the random <span class="hlt">substorms</span>, and (3) the large-scale structure of the solar wind plasma is responsible for the long intervals wherein no <span class="hlt">substorms</span> occur. Statistically, the recurrence period of periodically occurring <span class="hlt">substorms</span> is slightly shorter when the ram pressure of the solar wind is high, when the magnetic field strength of the solar wind is strong, when the Mach number of the solar wind is low, and when the polar-cap potential saturation parameter is high.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19740044937&hterms=Johnstone&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D20%26Ntt%3DJohnstone','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19740044937&hterms=Johnstone&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D20%26Ntt%3DJohnstone"><span>Study of a small magnetospheric <span class="hlt">substorm</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Johnstone, A. D.; Boyd, J. S.; Davis, T. N.</p> <p>1974-01-01</p> <p>Data from a rocket launched into the expansion <span class="hlt">phase</span> of an auroral <span class="hlt">substorm</span> have been compared with data from numerous ground stations and several space vehicles. It is shown that this magnetic and auroral <span class="hlt">substorm</span> has most of the features of larger <span class="hlt">substorms</span>; thus it is implied that the same plasma processes are involved in all <span class="hlt">substorms</span>. Some evidence is presented to link the auroral breakup with the field lines conjugate to the inner edge of the plasma sheet. The implications of these two results for <span class="hlt">substorm</span> morphology and the triggering mechanism of the <span class="hlt">substorm</span> instability are discussed. It is concluded that spatial gradients in plasma temperature are a likely cause.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1990JHATD..11..264L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1990JHATD..11..264L"><span>Magnetospheric <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lopez, Ramon E.</p> <p>1990-12-01</p> <p>The earth's magnetic tail acts as a reservoir for the energy that is extracted by the interaction between the solar wind and the earth's magnetosphere. Occasionally, a portion of that energy is released through a violent process known as a magnetospheric <span class="hlt">substorm</span>. The <span class="hlt">substorm</span> is one of the most important magnetospheric phenomena, and it is the subject of extensive research. Recent work utilizing data collected by the Active Magnetospheric Particle Tracer Explorers/Charge Composition Explorer satellite, built at APL, has contributed markedly to the understanding of <span class="hlt">substorms</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5221552','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5221552"><span>Evolution of magnetic configurations in the plasma sheet during a <span class="hlt">substorm</span> on March 19, 1978</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sun, W.; Kan, J.R.; Akasofu, S.I. )</p> <p>1991-09-01</p> <p>Evolution of the magnetic field configuration in the plasma sheet is modeled for an intense <span class="hlt">substorm</span> event on March 19, 1978. The model is based on the idea that the <span class="hlt">substorm</span> enhanced field-aligned currents are initiated in the ionosphere in response to an enhanced magnetospheric convection. The field-aligned currents in the model are determined from the ground-based magnetometer data with a time resolution of 5 min. The <span class="hlt">substorm</span> field-aligned currents are assumed to close in the plasma sheet to complete the <span class="hlt">substorm</span> current circuit. It is shown that the magnetic field produced by the <span class="hlt">substorm</span> current system in the model can reproduce several important <span class="hlt">substorm</span> signatures observed in the plasma sheet. These signatures include the taillike reconfiguration in the plasma sheet during the <span class="hlt">growth</span> <span class="hlt">phase</span>, the dipolarization of the plasma sheet associated with the <span class="hlt">substorm</span> expansion onset, and the formation of a new X line. A shortcoming of the model is that the plasma dynamics in the plasma sheet have been ignored. In spite of this shortcoming, however, the model demonstrates that the ionosphere, in response to an enhanced magnetospheric convection, can cause the plasma sheet to change its magnetic configuration to result in the <span class="hlt">substorm</span> signatures observed in the plasma sheet. The present study shows that it is possible for the ionosphere to play an active role in causing the observed reconfigurations of the plasma sheet during <span class="hlt">substorms</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EP%26S...67..162M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EP%26S...67..162M"><span>Strong induction effects during the <span class="hlt">substorm</span> on 27 August 2001</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mishin, V. V.; Mishin, V. M.; Lunyushkin, S. B.; Pu, Z.; Wang, C.</p> <p>2015-10-01</p> <p>We report on strong induction effects notably contributing to the cross polar cap potential drop and the energy balance during the <span class="hlt">growth</span> and active <span class="hlt">phases</span> of the <span class="hlt">substorm</span> on 27 August 2001. The inductance of the magnetosphere is found to be crucial for the energy balance and electrical features of the magnetosphere in the course of the <span class="hlt">substorm</span>. The inductive response to the switching on and off of the solar wind-magnetosphere generator exceeds the effect of the interplanetary magnetic field (IMF) variation. The induction effects are most apparent during the <span class="hlt">substorm</span> expansion onset when the rapid <span class="hlt">growth</span> of the ionospheric conductivity is accompanied by the fast release of the magnetic energy stored in the magnetotail during the <span class="hlt">growth</span> <span class="hlt">phase</span>. Using the magnetogram inversion technique, we estimated the magnetospheric inductance and effective ionospheric conductivity during the loading and unloading <span class="hlt">phases</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009PhDT........34G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009PhDT........34G"><span>Comparative study on dynamics associated with terrestrial and Jovian <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ge, Yasong</p> <p></p> <p>Terrestrial <span class="hlt">substorms</span> have been studied for over four decades and our understanding about this phenomenon has improved through those studies. However, many issues regarding <span class="hlt">substorms</span> are still controversial, especially the initiation mechanism of <span class="hlt">substorm</span> onset. To understand the initiation mechanism, we have to first answer some important questions. What is the <span class="hlt">substorm</span> expansion onset? What is the physics behind its phenomenological definition? Where does the initiation start? What is the relation of tail reconnection with near-Earth onsets? Where does tail reconnection occur? While one way to understand better the physics of <span class="hlt">substorms</span> is to increase the number of spacecraft and the resolution of ground observations, another way is to compare <span class="hlt">substorm</span> phenomena between different planets. In this study, we investigate the different <span class="hlt">phases</span> of <span class="hlt">substorms</span> both on the Earth and Jupiter. For Jovian dynamic event, we need to know if they are <span class="hlt">substorms</span>? How are they driven? How can we better understand terrestrial <span class="hlt">substorms</span> through studying Jovian <span class="hlt">substorms</span>? We used Polar, GOES, Cluster and ground-station observations to study terrestrial <span class="hlt">substorms</span> and used the Galileo observations to study Jovian dynamic events. A 3-day <span class="hlt">growth</span> <span class="hlt">phase</span> of Jovian <span class="hlt">substorm</span> is discovered, which is also found driven by the internal processes including mass-loading at Io instead of the solar wind. This discovery establishes the <span class="hlt">substorm</span> nature of those dynamics events which have counterparts of key elements of terrestrial <span class="hlt">substorms</span>, including the connection of those events with the Jupiter's polar auroral activity. Near-planet dipolarization caused by the mid-tail reconnection is also investigated. In the near-Earth tail region, dipolarizations appear to be associated with mid-tail reconnections, near-tail flow braking and formation of <span class="hlt">substorm</span> current wedge. In both magnetospheres, major onsets of <span class="hlt">substorms</span> are found to be due to the major tail reconnection which can globally release the loaded</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/298591','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/298591"><span>Multipoint study of a <span class="hlt">substorm</span> on February 9, 1995</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lui, A.T.; Williams, D.J.; McEntire, R.W.; Ohtani, S.; Zanetti, L.J.; Bristow, W.A.; Greenwald, R.A.; Newell, P.T.; Christon, S.P.; Mukai, T.; Tsuruda, K.; Yamamoto, T.; Kokubun, S.; Matsumoto, H.; Kojima, H.; Murata, T.; Fairfield, D.H.; Lepping, R.P.; Samson, J.C.; Rostoker, G.; Reeves, G.D.; Rodger, A.L.; Singer, H.J.</p> <p>1998-08-01</p> <p>An extended interval of strong northward interplanetary magnetic field (IMF) was observed by the Wind spacecraft located at an upstream distance of {approximately}193 R{sub E} from February 8{endash}10, 1995, with a brief break of southward IMF from 0200 to 0400 UT on February 9. This brief interval of southward IMF led to an isolated <span class="hlt">substorm</span> of moderate intensity ({approximately}500 nT) with expansion <span class="hlt">phase</span> starting at {approximately}0431 UT. This <span class="hlt">substorm</span> may be triggered by the northward turning of the IMF since its onset time matched well with the time expected for the arrival of the northward turning of the IMF at Earth. The <span class="hlt">substorm</span> activities were monitored by 11 spacecraft in space (Wind, IMP 8, Geotail, six geosynchronous satellites, one DMSP satellite, and Freja) and two networks of ground stations (Canopus and SuperDARN) covering both the northern and southern hemispheres. The extensive coverage of this event provides us with results (1) showing some unusual characteristics possibly related to the isolated nature of the <span class="hlt">substorm</span> and (2) revealing some surprising features difficult to reconcile with the traditional <span class="hlt">substorm</span> model. In the first category is unusually long duration of the <span class="hlt">growth</span> <span class="hlt">phase</span> and the long time delay between <span class="hlt">substorm</span> expansion onset and particle injection onset at the geosynchronous orbit. In the second category is new evidence for multiple particle acceleration sites during <span class="hlt">substorm</span> expansion and for sunward flow during the late expansion <span class="hlt">phase</span> of a <span class="hlt">substorm</span> being unrelated to a single acceleration site ({ital X} line) moving from the near-Earth tail to the more distant tail. We also present observations which show the possible optical signature on the ground of bursty bulk flows in the magnetotail. {copyright} 1998 American Geophysical Union</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EPSC....9..299M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EPSC....9..299M"><span>AMPERE observations of the Birkeland currents associated with <span class="hlt">substorms</span> and comparison with simple electrodynamic modelling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Milan, S. E.; Coxon, J. C.; Clausen, L. B. N.; Korth, H.; Anderson, B. J.</p> <p>2014-04-01</p> <p>We present observations of the global terrestrial Birkeland field-aligned current (FAC) pattern observed by the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) during a sequence of <span class="hlt">substorms</span>. The observations show that the region 1 and 2 current systems move to lower latitudes during the <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phase</span> and retreat to higher latitudes following <span class="hlt">substorm</span> expansion <span class="hlt">phase</span> onset. We interpret these observations within the framework of the expanding/contracting polar cap paradigm. This links expansion of the polar cap and equatorward motion of the auroras and FAC systems to the action of magnetopause reconnection increasing the open magnetic flux content of the magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM44A..02N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM44A..02N"><span>Coupling between pre-onset flows and <span class="hlt">substorm</span> onset waves</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nishimura, T.; Lyons, L. R.; Angelopoulos, V.; Donovan, E.; Mende, S. B.</p> <p>2015-12-01</p> <p>A critical, long-standing problem in <span class="hlt">substorm</span> research is identification of the sequence of events leading to <span class="hlt">substorm</span> expansion <span class="hlt">phase</span> onset. Recent THEMIS all-sky imager (ASI) array observations have shown a repeatable pre-onset sequence, which is initiated by a poleward boundary intensification (PBI) and is followed by auroral streamers moving equatorward (earthward flow in the plasma sheet) and then by <span class="hlt">substorm</span> onset. On the other hand, <span class="hlt">substorm</span> onset is also preceded by azimuthally propagating waves, indicating a possible importance of wave instability for triggering <span class="hlt">substorm</span> onset. However, it has been difficult to identify the link between fast flows and waves. We have found an isolated <span class="hlt">substorm</span> event that was well-instrumented with the Poker Flat incoherent scatter radar (PFISR), THEMIS white-light ASI, and multi-spectral ASI, where the auroral onset occurred within the PFISR and ASI fields-of-view. This <span class="hlt">substorm</span> onset was preceded by a PBI, and ionospheric flows propagated equatorward from the polar cap, crossed the PBI and reached the <span class="hlt">growth</span> <span class="hlt">phase</span> arc. This sequence provides evidence that flows from open magnetic field lines propagate across the open-closed boundary and reach the near-Earth plasma sheet prior to the onset. Quasi-stable oscillations in auroral luminosity and ionospheric density are found along the <span class="hlt">growth</span> <span class="hlt">phase</span> arc. These pre-onset auroral waves amplified abruptly at the onset time, soon after the equatorward flows reached the onset region. This sequence suggests a coupling process where pre-existing stable waves in the near-Earth plasma sheet interact with flows from further downtail and then evolve to onset instability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950011825&hterms=current+sheet&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dcurrent%2Bsheet','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950011825&hterms=current+sheet&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dcurrent%2Bsheet"><span>Global and local current sheet thickness estimates during the late <span class="hlt">growth</span> <span class="hlt">phase</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pulkkinen, T. I.; Baker, D. N.; Mitchell, D. G.; Mcpherron, Robert L.; Huang, C. Y.; Frank, L. A.</p> <p>1992-01-01</p> <p>The thinning and intensification of the cross tail current sheet during the <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phase</span> are analyzed during the CDAW 6 <span class="hlt">substorm</span> (22 Mar. 1979) using two complementary methods. The magnetic field and current sheet development are determined using data from two spacecraft and a global magnetic field model with several free parameters. These results are compared with the local calculation of the current sheet location and structure previously done by McPherron et al. Both methods lead to the conclusion that an extremely thin current sheet existed prior to the <span class="hlt">substorm</span> onset, and the thicknesses estimated by the two methods at <span class="hlt">substorm</span> onset agree relatively well. The plasma data from the ISEE 1 spacecraft at 13 R(sub E) show an anisotropy in the low energy electrons during the <span class="hlt">growth</span> <span class="hlt">phase</span> which disappears just before the <span class="hlt">substorm</span> onset. The global magnetic model results suggest that the field is sufficiently stretched to scatter such low energy electrons. The strong stretching may improve the conditions for the <span class="hlt">growth</span> of the ion tearing instability in the near Earth tail at <span class="hlt">substorm</span> onset.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920055303&hterms=ISEE-3&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DISEE-3','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920055303&hterms=ISEE-3&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DISEE-3"><span>ISEE 3 plasmoid and TCR observations during an extended interval of <span class="hlt">substorm</span> activity</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.; Smith, M. F.; Mazur, E. L.; Baker, D. N.; Iyemori, T.; Singer, H. J.; Greenstadt, E. W.</p> <p>1992-01-01</p> <p>On April 9-11, 1983, the ISEE 3 spacecraft was continuously located within the earth's magnetotail for more than 36 hours at downstream distances of X = -76 to -80 R(e). During this span of time, 12 major intervals of <span class="hlt">substorm</span> activity were observed in the AL index with good ISEE 3 telemetry coverage for 11 of them. In addition, there were two small <span class="hlt">substorms</span> outside of these intervals, both with complete observations in the distant tail. This unusual ISEE 3 data set provides a unique opportunity to test the predictions of the near-earth neutral line model. In particular, the hypothesis that energy stored in the tail lobes during the <span class="hlt">growth</span> <span class="hlt">phase</span> is later dissipated, in part, through the release of one or more plasmoids following expansion <span class="hlt">phase</span> onset is examined. Clear <span class="hlt">growth</span> <span class="hlt">phase</span> enhancements in the lobe magnetic field intensity preceded the onsets of nine of the <span class="hlt">substorms</span>. Plasmoids, or their lobe signatures, traveling compression regions (TCRs), were observed at ISEE 3 in association with all 11 of the major <span class="hlt">substorm</span> intervals for which there were ISEE observations, as well as for the two small <span class="hlt">substorms</span>. No plasmoids or TCRs were observed in the absence of <span class="hlt">substorm</span> activity. If these ISEE 3 observations are representative, then the release of plasmoids down the tail may be a feature common to all <span class="hlt">substorms</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009Ge%26Ae..49..303K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009Ge%26Ae..49..303K"><span>The recovery <span class="hlt">phase</span> of the superstrong magnetic storm of July 15-17, 2000: <span class="hlt">Substorms</span> and ULF pulsations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kleimenova, N. G.; Kozyreva, O. V.</p> <p>2009-06-01</p> <p>The geomagnetic observations, performed at the global network of ground-based observatories during the recovery <span class="hlt">phase</span> of the superstrong magnetic storm of July 15-17, 2000 (Bastille Day Event, Dst = -301 nT), have been analyzed. It has been indicated that magnetic activity did not cease at the beginning of the storm recovery <span class="hlt">phase</span> but abruptly shifted to polar latitudes. Polar cap <span class="hlt">substorms</span> were accompanied by the development of intense geomagnetic pulsations in the morning sector of auroral latitudes. In this case oscillations at frequencies of 1-2 and 3-4 mHz were observed at geomagnetic latitudes higher and lower than ˜62°, respectively. It has been detected that the spectra of variations in the solar wind dynamic pressure and the amplitude spectra of geomagnetic pulsations on the Earth’s surface were similar. Wave activity unexpectedly appeared in the evening sector of auroral latitudes after the development of near-midnight polar <span class="hlt">substorms</span>. It has been established that the generation of Pc5 pulsations (in this case at frequencies of 3-4 mHz) was spatially asymmetric about noon during the late stage of the recovery <span class="hlt">phase</span> of the discussed storm as took place during the recovery <span class="hlt">phase</span> of the superstrong storms of October and November 2003. Intense oscillations were generated in the morning sector at the auroral latitudes and in the postnoon sector at the subauroral and middle latitudes. The cause of such an asymmetry, typical of the recovery <span class="hlt">phase</span> of superstrong magnetic storms, remains unknown.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EP%26S...67..195C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EP%26S...67..195C"><span>The February 24, 2010 <span class="hlt">substorm</span>: a refined view involving a pseudobreakup/expansive <span class="hlt">phase</span>/poleward boundary intensification sequence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Connors, Martin; Russell, Christopher T.; Chu, Xiangning; McPherron, Robert L.</p> <p>2015-12-01</p> <p>A <span class="hlt">substorm</span> on February 24, 2010 was chosen for study by Connors et al. (Geophys. Res. Lett. 41:4449-4455, 2014) due to simple symmetric subauroral magnetic perturbations observed in North America. It was shown that a <span class="hlt">substorm</span> current wedge (SCW) three-dimensional current model could represent these perturbations well, gave a reasonable representation of auroral zone perturbations, and matched field-aligned currents determined in space from the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) project. The conclusion was that <span class="hlt">substorm</span> onset was at approximately 4:30 UT and that the <span class="hlt">substorm</span> current wedge (SCW) formed in the region 1 (more poleward) current system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990078591&hterms=boundary+Edge+Effect&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dboundary%2BEdge%2BEffect','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990078591&hterms=boundary+Edge+Effect&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dboundary%2BEdge%2BEffect"><span>Polar Cap Area and Boundary Motion During <span class="hlt">Substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brittnacher, M.; Germany, G. A.; Fillingim, M. O.; Parks, G. K.; Spann, James F., Jr.</p> <p>1998-01-01</p> <p>The area of the polar cap as a function of local time and <span class="hlt">substorm</span> <span class="hlt">phase</span> was measured using images from the Polar Ultraviolet Imager (UVI) for different interplanetary magnetic field (IMF) orientations during three <span class="hlt">substorms</span> in January 1997. We measured changes in the polar cap area and motion of the poleward and equatorward boundary of the auroral oval as determined by UVI images. It was found that the polar cap boundary is strongly influenced by thinning of the oval, decrease in polar cap structures, the poleward expansion of the <span class="hlt">substorm</span> at midnight and the fading of luminosity below the instrument sensitivity threshold. Generally these effects dominate over the latitudinal motion of the auroral oval at its equatorward edge. A new feature is that the polar cap region clears of precipitation during the <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phase</span>, which expands the size of the polar cap but may not necessarily be related to an expansion of the open flux. We present a new finding that the increase in polar cap area prior to onset and the decrease in the area following it are independent of the strength of the southward IMF component. For one case the polar cap area increased while the southward component of the IMF was no less than -0.5 nT. These observations have strong implications for models that use the polar cap area to estimate the magnitude of energy storage in the lobe magnetic field and loss during <span class="hlt">substorms</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMSM54A..06M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMSM54A..06M"><span>Investigation of triggering mechanism of <span class="hlt">substorm</span> through the analysis of Geotail and Themis data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Machida, S.; Miyashita, Y.; Ieda, A.; Nose, M.; Angelopoulos, V.; McFadden, J. P.; Auster, H.</p> <p>2011-12-01</p> <p>In our previous study, we have adopted a superposed epoch analysis method to the Geotail data to understand the triggering mechanism of <span class="hlt">substorm</span>. Further, we have proposed a new scheme of <span class="hlt">substorm</span> called "Catapult Current Sheet Relaxation Model" to explain our results. As an extension of these works, we adopted the same method of analysis to the Themis spacecraft data, and found that there are both the same and different characteristics between the results of Themis and Geotail. It is of interest that clear differences are present even if we use the same data set of Themis but adopting different lists of auroral breakups, i.e., <span class="hlt">substorm</span> onsets. These differences seem to be attributed to the intensity of <span class="hlt">substorm</span>. Large <span class="hlt">substorms</span> tend to have southward magnetic field variations related to the plasma sheet thinning which is known as a notable characteristic during a <span class="hlt">growth</span> <span class="hlt">phase</span>, near the Earth compared to small <span class="hlt">substorms</span>. However, the convective earthward flows are weakened just for a few minutes prior to the onset, followed by notable enhancement of the earthward flows after the onset. On the other hand, the southward variations in the magnetic field for small <span class="hlt">substorms</span> can be seen in the tailward side compared to large <span class="hlt">substorms</span>. While, the northward magnetic field variations after the onset can be also seen in the tailward side. Furthermore, the earthward convective flows which are not produced by magnetic reconnection seem to develop for moderate class of <span class="hlt">substorms</span> just prior to the onset. Those differences can be a crucial clue to solve the issue of <span class="hlt">substorm</span> triggering.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GSL.....3...12M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GSL.....3...12M"><span>Relation of the auroral <span class="hlt">substorm</span> to the <span class="hlt">substorm</span> current wedge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McPherron, Robert L.; Chu, Xiangning</p> <p>2016-12-01</p> <p>The auroral <span class="hlt">substorm</span> is an organized sequence of events seen in the aurora near midnight. It is a manifestation of the magnetospheric <span class="hlt">substorm</span> which is a disturbance of the magnetosphere brought about by the solar wind transfer of magnetic flux from the dayside to the tail lobes and its return through the plasma sheet to the dayside. The most dramatic feature of the auroral <span class="hlt">substorm</span> is the sudden brightening and poleward expansion of the aurora. Intimately associated with this expansion is a westward electrical current flowing across the bulge of expanding aurora. This current is fed by a downward field-aligned current (FAC) at its eastern edge and an upward current at its western edge. This current system is called the <span class="hlt">substorm</span> current wedge (SCW). The SCW forms within a minute of auroral expansion. FAC are created by pressure gradients and field line bending from shears in plasma flow. Both of these are the result of pileup and diversion of plasma flows in the near-earth plasma sheet. The origins of these flows are reconnection sites further back in the tail. The auroral expansion can be explained by a combination of a change in field line mapping caused by the <span class="hlt">substorm</span> current wedge and a tailward <span class="hlt">growth</span> of the outer edge of the pileup region. We illustrate this scenario with a complex <span class="hlt">substorm</span> and discuss some of the problems associated with this interpretation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19890046142&hterms=1983&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3D1983','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19890046142&hterms=1983&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3D1983"><span>The CDAW-8 <span class="hlt">substorm</span> event on 28 January 1983 - A detailed global study</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Baker, D. N.; Fairfield, D. H.; Craven, J. D.; Frank, L. A.; Elphic, R. C.</p> <p>1988-01-01</p> <p>A small, isolated <span class="hlt">substorm</span> with an expansion <span class="hlt">phase</span> onset at 0739 UT on January 28, 1983 was well observed by ground-based instrumentation as well as by low- and high-altitude spacecraft. Because of the comprehensive nature of the data coverage, including ISEE-3 identification of plasmoid signatures in the deep tail (about 220 earth radii) associated with the <span class="hlt">substorm</span>, a detailed timeline of the <span class="hlt">growth</span>, expansion, and recovery <span class="hlt">phases</span> of the <span class="hlt">substorm</span> can be provided. The plasma, energetic particle, and field signatures at ISEE-3 are considered within the framework of the near-earth data. Quantitative estimates of <span class="hlt">substorm</span> energy input and output relationships are made for this case, and the timing and physical dimensions of the deep tail disturbance implied are evaluated by the global observations available.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000JGR...10521109P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000JGR...10521109P"><span>Small <span class="hlt">substorms</span>: Solar wind input and magnetotail dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Petrukovich, A. A.; Baumjohann, W.; Nakamura, R.; Mukai, T.; Troshichev, O. A.</p> <p></p> <p>We investigated properties of 43 small magnetospheric <span class="hlt">substorms</span>. Their general signatures were found to be consistent with the so-called contracted oval or northern Bz <span class="hlt">substorms</span>. Small but clear pressure changes in the tail corresponding to <span class="hlt">growth</span> and expansion <span class="hlt">phases</span> detected in about a half of cases testify that these <span class="hlt">substorms</span> follow the same loading-unloading scheme as the larger ones. However, rate of the solar wind energy accumulation in the magnetosphere was low due to azimuthal IMF orientation with dominating IMFBy and small fluctuating IMFBz. Plasma sheet signatures could be very strong and likely were localized in their cross-tail size. Negative bays in auroral X magnetograms were of order of 100-300 nT, with maxima at Bear Island station (71° geomagnetic latitude) and in few cases were delayed after magnetotail onsets by tens of minutes. Small <span class="hlt">substorms</span> probably differ from their larger counterparts in a way that coherency of the magnetotail reconfiguration in the inner and middle-tail regions and across the tail is lost in smaller <span class="hlt">substorms</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_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/2011AGUFMSA41B1852G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMSA41B1852G"><span>Variations of <span class="hlt">Substorm</span> Electric-field Components Measured with the Poker-Flat Incoherent-Scatter Radar</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gudivada, K.; Watkins, B.</p> <p>2011-12-01</p> <p>North-South and East-West components of the auroral-zone electric field have been measured with the incoherent-scatter radar at Poker-Flat, Alaska. The <span class="hlt">phased</span>-array technology incorporated with the radar system provides a new method to determine electric fields as a function of latitude with minimal spatial and temporal ambiguity. Successive radar pulses are transmitted in thirteen antenna directions. Doppler data are combined and integrated to determine electric field values from 66 to 68 degrees latitude in 0.25 degree steps. Data periods have been selected when <span class="hlt">substorm</span> currents, as detected from the Alaskan magnetometer chain, are within range of the radar. Specific events near the onset of magnetic <span class="hlt">substorms</span> have been examined to determine average variations of the electric field with respect to <span class="hlt">substorm</span> onset time. The northward component of the field is typically about 20-30mV/m in the evening and transitions to values near zero about one hour before <span class="hlt">substorm</span> onset (we identify this period as the <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phase</span>) and then adopts southward values about 20-30mV/m at the time of <span class="hlt">substorm</span> onset. The east-west component values of the electric field are near zero in the evening, and then go to about 10mV/m directed westward during the <span class="hlt">growth</span> <span class="hlt">phase</span> and after <span class="hlt">substorm</span> onset.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990100919&hterms=BZ&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DBZ','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990100919&hterms=BZ&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DBZ"><span>Dynamics of the Auroral Luminosity Boundary of the Polar Cap During <span class="hlt">Substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brittnacher, M. J.; Chua, D.; Fillingim, M. O.; Parks, G. K.; Spann, James F., Jr.; Germany, G. A.</p> <p>1999-01-01</p> <p>The area of the polar cap during <span class="hlt">substorms</span> has been measured using images from the Polar Ultraviolet Imager (UVI) for different interplanetary magnetic field (IMF) conditions. Changes in the poleward boundary of auroral luminosity have been analyzed in relation to <span class="hlt">substorm</span> <span class="hlt">phase</span> and IMF orientation. Reconnection models of flux transport into the polar cap during the <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phase</span>, and loss from the polar cap during the expansion <span class="hlt">phase</span>, provide a framework by which these UVI observations can be analyzed. By comparison of the observations with the model predictions we can determine to what extent these models accurately predict the polar cap dynamics, and also where anomalous behavior calls for a new understanding of the dynamics beyond what these models provide. It was found that the polar cap boundary near noon and midnight usually shifted down in latitude by 1-2 degrees and 3-4 degrees respectively, increasing the area of the polar cap during the <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phase</span> as predicted. However, this <span class="hlt">growth</span> <span class="hlt">phase</span> phenomenon also unexpectedly occurs independently of the IMF Bz component, as shown for a <span class="hlt">substorm</span> on January 9, 1997. The polar cap area also increased due to motion of the dawn and dusk aurora to lower latitudes, although the latitudinal shifts were asymmetric, not always concurrent, and continued well into the <span class="hlt">substorm</span> expansion <span class="hlt">phase</span>. The polar cap area decreased immediately following the expansion <span class="hlt">phase</span> due to the poleward motion of the aurora on the nightside, consistent with the model prediction. What is not explained by the models is that the poleward auroral boundary in the nightside region sometimes reached very high latitudes (greater than 80 degrees MLat) greatly decreasing the polar cap area, independent of the magnitude of the <span class="hlt">substorm</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AnGeo..31..387A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AnGeo..31..387A"><span>The relationship between the magnetosphere and magnetospheric/auroral <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Akasofu, S.-I.</p> <p>2013-03-01</p> <p>On the basis of auroral and polar magnetic <span class="hlt">substorm</span> studies, the relationship between the solar wind-magnetosphere dynamo (the DD dynamo) current and the <span class="hlt">substorm</span> dynamo (the UL dynamo) current is studied. The characteristics of both the DD and UL currents reveal why auroral <span class="hlt">substorms</span> consist of the three distinct <span class="hlt">phases</span> after the input power ɛ is increased above 1018 erg s-1. (a) The <span class="hlt">growth</span> <span class="hlt">phase</span>; the magnetosphere can accumulate magnetic energy for auroral <span class="hlt">substorms</span>, when the ionosphere cannot dissipate the power before the expansion <span class="hlt">phase</span>. (b) The expansion <span class="hlt">phase</span>; the magnetosphere releases the accumulated magnetic energy during the <span class="hlt">growth</span> <span class="hlt">phase</span> in a pulse-like manner in a few hours, because it tries to stabilize itself when the accumulated energy reaches to about 1023 erg s-1. (c) The recovery <span class="hlt">phase</span>; the magnetosphere becomes an ordinary dissipative system after the expansion <span class="hlt">phase</span>, because the ionosphere becomes capable of dissipating the power with the rate of 1018 ~ 1019 erg s-1. On the basis of the above conclusion, it is suggested that the magnetosphere accomplishes the pulse-like release process (resulting in spectacular auroral activities) by producing plasma instabilities in the current sheet, thus reducing the current. The resulting contraction of the magnetic field lines (expending the accumulated magnetic energy), together with break down of the "frozen-in" field condition at distances of less than 10 RE, establishes the <span class="hlt">substorm</span> dynamo that generates an earthward electric field (Lui and Kamide, 2003; Akasofu, 2011). It is this electric field which manifests as the expansion <span class="hlt">phase</span>. A recent satellite observation at a distance of as close as 8.1 RE by Lui (2011) seems to support strongly the occurrence of the chain of processes suggested in the above. It is hoped that although the concept presented here is very crude, it will serve in providing one way of studying the three <span class="hlt">phases</span> of auroral <span class="hlt">substorms</span>. In turn, a better understanding of auroral</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950056472&hterms=Cowley&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D40%26Ntt%3DCowley','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950056472&hterms=Cowley&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D40%26Ntt%3DCowley"><span>The response of ionospheric convection in the polar cap to <span class="hlt">substorm</span> activity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lester, M.; Lockwood, M.; Yeoman, T. K.; Cowley, S. W. H.; Luehr, H.; Bunting, R.; Farrugia, C. J.</p> <p>1995-01-01</p> <p>We report multi-instrument observations during an isolated <span class="hlt">substorm</span> on 17 October 1989. The European Incoherent Scatter (EISCAT) radar operated in the SP-UK-POLI mode measuring ionospheric convection at latitudes 71 deg Lambda - 78 deg Lambda. Sub-Auroral Magnetometer Network (SAMNET) and the EISCAT Magnetometer Cross provide information on the timing of <span class="hlt">substorm</span> expansion <span class="hlt">phase</span> onset and subsequent intensifications, as well as the location of the field aligned and ionospheric currents associated with the <span class="hlt">substorm</span> current wedge. Interplanetary Monitoring Platform-8 (IMP-8) magnetic field data are also included. Evidence of a <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phase</span> is provided by the equatorward motion of a flow reversal boundary across the EISCAT radar field of view at 2130 MLT, following a southward turning of the interplanetary magnetic field (IMF). We infer that the polar cap expanded as a result of the addition of open magnetic flux in the tail lobes during this interval. The flow reversal boundary, which is a lower limit to the polar cap boundary, reached an invariant latitude equatorward of 71 deg Lambda by the time of the expansion <span class="hlt">phase</span> onset. We conclude that the <span class="hlt">substorm</span> onset region in the ionosphere, defined by the westward electrojet, mapped to a part of the tail radially earthward of the boundary between open and closed magnetic flux, the distant neutral line. Thus the <span class="hlt">substorm</span> was not initiated at the distant neutral line, although there is evidence that it remained active during the expansion <span class="hlt">phase</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRA..119.3333N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRA..119.3333N"><span>Coordinated ionospheric observations indicating coupling between preonset flow bursts and waves that lead to <span class="hlt">substorm</span> onset</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nishimura, Y.; Lyons, L. R.; Nicolls, M. J.; Hampton, D. L.; Michell, R. G.; Samara, M.; Bristow, W. A.; Donovan, E. F.; Spanswick, E.; Angelopoulos, V.; Mende, S. B.</p> <p>2014-05-01</p> <p>A critical, long-standing problem in <span class="hlt">substorm</span> research is identification of the sequence of events leading to <span class="hlt">substorm</span> expansion <span class="hlt">phase</span> onset. Recent Time History of Events and Macroscale Interactions during <span class="hlt">Substorms</span> (THEMIS) all-sky imager (ASI) array observations have shown a repeatable preonset sequence, which is initiated by a poleward boundary intensification (PBI) and is followed by auroral streamers moving equatorward (earthward flow in the plasma sheet) and then by <span class="hlt">substorm</span> onset. On the other hand, <span class="hlt">substorm</span> onset is also preceded by azimuthally propagating waves, indicating a possible importance of wave instability for triggering <span class="hlt">substorm</span> onset. However, it has been difficult to identify the link between fast flows and waves. We have found an isolated <span class="hlt">substorm</span> event that was well instrumented with the Poker Flat incoherent scatter radar (PFISR), THEMIS white-light ASI, and multispectral ASI, where the auroral onset occurred within the PFISR and ASI fields of view. This <span class="hlt">substorm</span> onset was preceded by a PBI, and ionospheric flows propagated equatorward from the polar cap, crossed the PBI, and reached the <span class="hlt">growth</span> <span class="hlt">phase</span> arc. This sequence provides evidence that flows from open magnetic field lines propagate across the open-closed boundary and reach the near-Earth plasma sheet prior to the onset. Quasi-stable oscillations in auroral luminosity and ionospheric density are found along the <span class="hlt">growth</span> <span class="hlt">phase</span> arc. These preonset auroral waves amplified abruptly at the onset time, soon after the equatorward flows reached the onset region. This sequence suggests a coupling process where preexisting stable waves in the near-Earth plasma sheet interact with flows from farther downtail and then evolve to onset instability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E.696D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E.696D"><span>``Polar'' and ``high-latitude'' <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Despirak, Irina; Lubchich, Andris; Kleimenova, Natalia</p> <p></p> <p>All <span class="hlt">substorms</span> observed at high latitudes can be divided into 2 types - "polar" (observed only at > 70º latitudes in the absence of <span class="hlt">substorms</span> at <70º latitudes during the day) and "high-latitude" <span class="hlt">substorms</span> (propagating from auroral (<70º) to polar (> 70º) geomagnetic latitudes). The aim of this study was to compare solar wind conditions during these two types of <span class="hlt">substorms</span>. For this purpose, we used the data of IMAGE magnetometers and OMNI solar wind data for 1995, 2000, 2006-2011 periods. There were selected 105 "polar" and 55 "high-latitude" <span class="hlt">substorms</span>. It is shown that "polar" <span class="hlt">substorms</span> observed during the late recovery <span class="hlt">phase</span> of a geomagnetic storm, after passing of the high speed stream of the solar wind (when the velocity is reduced from high to low values). "High-latitude" <span class="hlt">substorms</span>, on the contrary, are observed during passing of the recurrent high-speed stream of the solar wind, increased values of the southward B _{Z }component of the IMF and E _{Y} component of the electric field, increased temperature and pressure of the solar wind. Also, it is noted that variability of these solar wind parameters for the “high-latitude” <span class="hlt">substorms</span> is stronger than for “polar” <span class="hlt">substorms</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19880059315&hterms=field+magnetic+Earth&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dfield%2Bmagnetic%2BEarth','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19880059315&hterms=field+magnetic+Earth&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dfield%2Bmagnetic%2BEarth"><span>Plasma and magnetic field variations in the distant magnetotail associated with near-earth <span class="hlt">substorm</span> effects</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Baker, D. N.; Bame, S. J.; Mccomas, D. J.; Zwickl, R. D.; Slavin, J. A.; Smith, E. J.</p> <p>1987-01-01</p> <p>Examination of many individual event periods in the ISEE 3 deep-tail data set has suggested that magnetospheric <span class="hlt">substorms</span> produce a characteristic pattern of effects in the distant magnetotail. During the <span class="hlt">growth</span>, or tail-energy-storage <span class="hlt">phase</span> of <span class="hlt">substorms</span>, the magnetotail appears to grow diametrically in size, often by many earth radii. Subsequently, after the <span class="hlt">substorm</span> expansive <span class="hlt">phase</span> onset at earth, the distant tail undergoes a sequence of plasma, field, and energetic-particle variations as large-scale plasmoids move rapidly down the tail following their disconnection from the near-earth plasma sheet. ISEE 3 data are appropriate for the study of these effects since the spacecraft remained fixed within the nominal tail location for long periods. Using newly available auroral electrojet indices (AE and AL) and Geo particle data to time <span class="hlt">substorm</span> onsets at earth, superposed epoch analyses of ISEE 3 and near-earth data prior to, and following, <span class="hlt">substorm</span> expansive <span class="hlt">phase</span> onsets have been performed. These analyses quantify and extend substantially the understanding of the deep-tail pattern of response to global <span class="hlt">substorm</span>-induced dynamical effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900057460&hterms=electrodynamics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Delectrodynamics','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900057460&hterms=electrodynamics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Delectrodynamics"><span><span class="hlt">Substorm</span> electrodynamics</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stern, David P.</p> <p>1990-01-01</p> <p>The present one-dimensional model analysis of <span class="hlt">substorm</span> electrodynamics proceeds from the standard scenario in which the plasma sheet collapses into a neutral sheet, and magnetic merging occurs between the two tail lobes; plasma flows into the neutral sheet from the lobes and the sides, undergoing acceleration in the dawn-dusk direction. The process is modified by the tendency of the accelerated plasma to unbalance charge neutrality, leading to an exchange of electrons with the ionosphere in order to maintain neutrality. The cross-tail current is weakened by the diversion: this reduces the adjacent lobe-field intensity, but without notable effects apart from a slight expansion of the tail boundary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JGRA..115.0I04M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JGRA..115.0I04M"><span>A superposed epoch analysis of auroral evolution during <span class="hlt">substorms</span>: Local time of onset region</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Milan, S. E.; Grocott, A.; Hubert, B.</p> <p>2010-10-01</p> <p>Previous workers have shown that the magnetic local time (MLT) of <span class="hlt">substorm</span> onset depends on the prevailing east-west component of the interplanetary magnetic field (IMF). To investigate the influence of the onset MLT on the subsequent auroral response we perform a superposed epoch analysis of the auroral evolution during approximately 2000 <span class="hlt">substorms</span> using observations from the FUV instrument on the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) spacecraft. We subdivide the <span class="hlt">substorms</span> by onset latitude and onset local time before determining average auroral images before and after <span class="hlt">substorm</span> onset, for both electron and proton aurorae. We find that during the <span class="hlt">growth</span> <span class="hlt">phase</span> there is preexisting auroral emission in the MLT sector of the subsequent onset. After onset the auroral bulge expands eastward and westward, but remains centered on the onset sector. Approximately 30 min after onset, during the <span class="hlt">substorm</span> recovery <span class="hlt">phase</span>, the peaks in electron and proton auroral emission move into the postnoon and prenoon sectors, respectively, reflecting the “average” auroral precipitation patterns determined by previous studies. Superposed epoch analysis of the interplanetary magnetic field for the <span class="hlt">substorms</span> under study suggests that the BY component of the IMF must be biased toward positive or negative values for up to a day prior to onset for the onset MLT to be influenced.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.2687S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.2687S"><span>MESSENGER observations of <span class="hlt">substorm</span> activity in Mercury's near magnetotail</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, Wei-Jie; Slavin, James; Fu, Suiyan; Raines, Jim; Zong, Qiu-Gang; Yao, Zhonghua; Pu, Zuyin; Shi, Quanqi; Poh, Gangkai; Boardsen, Scott; Imber, Suzanne; Sundberg, Torbjörn; Anderson, Brian; Korth, Haje; Baker, Daniel</p> <p>2015-04-01</p> <p>MESSENGER magnetic field and plasma measurements taken during crossings of Mercury's magnetotail from 2011 to 2014 have been examined for evidence of <span class="hlt">substorm</span> activity. A total of 32 events were found during which an Earth-like <span class="hlt">growth</span> <span class="hlt">phase</span> was followed by clear near-tail expansion <span class="hlt">phase</span> signatures. During the <span class="hlt">growth</span> <span class="hlt">phase</span>, the lobe of the tail loads with magnetic flux while the plasma sheet thins due to the increased lobe magnetic pressure. MESSENGER is often initially in the plasma sheet and then moves into the lobe during the <span class="hlt">growth</span> <span class="hlt">phases</span>. The averaged time scale of the loading is around 1 min, consistent with previous observations of Mercury's Dungey cycle. The dipolarization front that marks the initiation of the <span class="hlt">substorm</span> expansion <span class="hlt">phase</span> is only a few seconds in duration. The spacecraft then abruptly enters the plasma sheet due to the plasma sheet expansion as reconnection-driven flow from the near-Mercury neutral line encounters the stronger magnetic fields closer to the planet. <span class="hlt">Substorm</span> activity in the near tail of Mercury is quantitatively very similar to the Earth despite the very compressed time scale.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950015909','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950015909"><span><span class="hlt">Substorm</span> theories: United they stand, divided they fall</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>1995-01-01</p> <p>Consensus on the timing and mapping of <span class="hlt">substorm</span> features has permitted a synthesis of <span class="hlt">substorm</span> models. Within the synthesis model the mechanism for onset of <span class="hlt">substorm</span> expansion is still unknown. Possible mechanisms are: <span class="hlt">growth</span> of an ion tearing mode, current disruption by a cross-field current instability, and magnetosphere-ionosphere coupling. While the synthesis model is consistent with overall <span class="hlt">substorm</span> morphology, including near-Earth onset, none of the onset theories, taken individually, appear to account for <span class="hlt">substorm</span> expansion onset. A grand synthesis with unification of the underlying onset theories appears necessary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19720033797&hterms=Auroras&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DAuroras','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19720033797&hterms=Auroras&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DAuroras"><span>Midday auroras and magnetospheric <span class="hlt">substorms</span>.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Akasofu, S. I.</p> <p>1972-01-01</p> <p>Auroral activity in the midday sector is examined in some detail on the basis of all-sky photographs taken from Pyramida, Spitzbergen. The equatorward motion of the midday auroras observed during <span class="hlt">substorms</span> and the subsequent poleward shift during the recovery <span class="hlt">phase</span> are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JGRA..118.7714M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JGRA..118.7714M"><span>The detailed spatial structure of field-aligned currents comprising the <span class="hlt">substorm</span> current wedge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Murphy, Kyle R.; Mann, Ian R.; Rae, I. Jonathan; Waters, Colin L.; Frey, Harald U.; Kale, Andy; Singer, Howard J.; Anderson, Brian J.; Korth, Haje</p> <p>2013-12-01</p> <p>We present a comprehensive two-dimensional view of the field-aligned currents (FACs) during the late <span class="hlt">growth</span> and expansion <span class="hlt">phases</span> for three isolated <span class="hlt">substorms</span> utilizing in situ observations from the Active Magnetosphere and Planetary Electrodynamics Response Experiment and from ground-based magnetometer and optical instrumentation from the Canadian Array for Realtime Investigations of Magnetic Activity and Time History of Events and Macroscale Interactions during <span class="hlt">Substorms</span> ground-based arrays. We demonstrate that the structure of FACs formed during the expansion <span class="hlt">phase</span> and associated with the <span class="hlt">substorm</span> current wedge is significantly more complex than a simple equivalent line current model comprising a downward FAC in the east and upward FAC in the west. This two-dimensional view demonstrates that azimuthal bands of upward and downward FACs with periodic structuring in latitude form across midnight and can span up to 8 h of magnetic local time. However, when averaged over latitude, the overall longitudinal structure of the net FACs resembles the simpler equivalent line current description of the <span class="hlt">substorm</span> current wedge (SCW). In addition, we demonstrate that the upward FAC elements of the structured SCW are spatially very well correlated with discrete aurora during the <span class="hlt">substorm</span> expansion <span class="hlt">phase</span> and that discrete changes in the FAC topology are observed in the late <span class="hlt">growth</span> <span class="hlt">phase</span> prior to auroral <span class="hlt">substorm</span> expansion <span class="hlt">phase</span> onset. These observations have important implications for determining how the magnetosphere and ionosphere couple during the late <span class="hlt">growth</span> <span class="hlt">phase</span> and expansion <span class="hlt">phase</span>, as well as providing important constraints on the magnetospheric generator of the FACs comprising the SCW.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSM54A..03F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSM54A..03F"><span>The Extent to Which Dayside Reconnection Drives Field-Aligned Currents During <span class="hlt">Substorms</span></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.; Shortt, M. W.; Coxon, J.; Rae, J.; Freeman, M. P.; Kalmoni, N. M. E.; Jackman, C. M.; Anderson, B. J.</p> <p>2016-12-01</p> <p>Field-aligned currents, also known as Birkeland currents, are the agents by which energy and momentum is transferred to the ionosphere from the magnetosphere and solar wind. In order to understand this coupling, it is necessary to analyze the variations in these current systems with respect to the main energy sources of the solar wind and <span class="hlt">substorms</span>. In this study, we perform a superposed epoch analysis of field-aligned currents determined by the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) project with respect to <span class="hlt">substorm</span> expansion <span class="hlt">phase</span> onsets identified using the <span class="hlt">Substorm</span> Onsets and <span class="hlt">Phases</span> from Indices of the Electrojet (SOPHIE) technique. We examine the total upward and downward currents separately in the noon, dusk, dawn and midnight sectors. Our results show that the dusk and dawn currents have up to a 66% linear correlated with the dayside reconnection rate estimated from solar wind measurements, whereas the noon and midnight currents are not. The noon currents show little or no variation throughout the <span class="hlt">substorm</span> cycle. The midnight currents follows the dusk currents up to 20 min before onset, after which the midnight current increases more rapidly and exponentially. At <span class="hlt">substorm</span> onset, the exponential <span class="hlt">growth</span> rate increases. While the midnight field-aligned currents grow exponentially after <span class="hlt">substorm</span> onset, the auroral indices vary with a 1/6th power law. Overall, our results show that the <span class="hlt">growth</span> and decay rates of the Region 1 and 2 current systems, which are strongest at dawn and dusk, are directly driven by the solar wind, whereas the <span class="hlt">growth</span> and decay rates of the <span class="hlt">substorm</span> current system, which are dominant at midnight, act independently of the upstream driver.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM53E..05M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM53E..05M"><span>Changes in Magnetosphere-Ionosphere Coupling and FACs Associated with <span class="hlt">Substorm</span> Onset (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Murphy, K. R.; Mann, I. R.; Rae, I. J.; Waters, C. L.; Anderson, B. J.; Korth, H.; Milling, D. K.; Singer, H. J.; Frey, H. U.</p> <p>2013-12-01</p> <p>Field aligned currents (FACs) are crucial for the communication of information between the ionosphere and magnetosphere. Utilising in-situ observations from the Iridium constellation and Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) we provide detailed observations of the FAC topology through the <span class="hlt">substorm</span> <span class="hlt">growth</span> and expansion <span class="hlt">phases</span>. In particular, for an isolated <span class="hlt">substorm</span> on 16 February 2010 we demonstrate a clear and localized reduction in the FACs at least 6 minutes prior to auroral onset. A new auroral arc forms in the region of reduced FAC on closed field lines and initially expands azimuthally in wave like fashion. This newly formed arc continues to brighten and expands poleward signifying the start of the <span class="hlt">substorm</span> expansion <span class="hlt">phase</span>. We argue that the change in FACs observed prior to onset is the result of a change in the magnetosphere-ionosphere (M-I) coupling in a region local to the subsequent auroral onset. Such a change implies an important role for M-I coupling in destabilising the near-Earth tail during magnetospheric <span class="hlt">substorms</span> and perhaps more importantly in selecting the location in the ionosphere where auroral onset begins. Further, we provide, a comprehensive in-situ two-dimensional view of the FAC topology associated with the <span class="hlt">substorm</span> current wedge and westward traveling surge during the <span class="hlt">substorm</span> expansion <span class="hlt">phase</span>. We demonstrate that these current structures, when integrated with latitude to produce a net FAC as a function of MLT, have the same structure as the equivalent line current system comprising the SCW. Moreover, regions of upward FAC are associated with discrete auroral forms during the <span class="hlt">substorm</span> expansion <span class="hlt">phase</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMSM52B..04S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMSM52B..04S"><span>Discrete Aurora, Ionospheric Feedback Instability, and <span class="hlt">Substorm</span> Development</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Streltsov, A. V.; Pedersen, T. R.; Mishin, E. V.; Snyder, A. L.</p> <p>2009-12-01</p> <p>We report on dynamics of discrete aurorla arcs and ULF electromagnetic waves, observed with ground optical and magnetic instruments during a <span class="hlt">substorm</span> onset on 29 October 2008. These observations were performed as a part of the ionospheric heating experiment conducted at the High Frequency Active Auroral Research Program (HAARP) facility in Alaska. The experiment was aimed at disrupting/reconfiguring the current system associated with a quiet auroral arc during the <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phase</span> by the development of the ionospheric feedback instability (IFI) in the region of the downward current adjacent to the arc. These observations support the idea that geomagnetic <span class="hlt">substorms</span> are closely connected with the IFI development and generation of intense ULF electromagnetic waves and density structures in the downward current region. They also show strong correlation between generation of ULF waves and spatiotemporal dynamics of discrete auroral arcs. However, the questions as to whether heating of the ionosphere with HAARP could affect the IFI development and whether IFI plays the role of a triggering mechanism for the breakup of the stable auroral arc and subsequent <span class="hlt">substorm</span> onset or it is primarily a consequence remain unanswered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990063839&hterms=open+source&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dopen%2Bsource','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990063839&hterms=open+source&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dopen%2Bsource"><span>Source Distributions of <span class="hlt">Substorm</span> Ions Observed in the Near-Earth Magnetotail</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ashour-Abdalla, M.; El-Alaoui, M.; Peroomian, V.; Walker, R. J.; Raeder, J.; Frank, L. A.; Paterson, W. R.</p> <p>1999-01-01</p> <p>This study employs Geotail plasma observations and numerical modeling to determine sources of the ions observed in the near-Earth magnetotail near midnight during a <span class="hlt">substorm</span>. The <span class="hlt">growth</span> <span class="hlt">phase</span> has the low-latitude boundary layer as its most important source of ions at Geotail, but during the expansion <span class="hlt">phase</span> the plasma mantle is dominant. The mantle distribution shows evidence of two distinct entry mechanisms: entry through a high latitude reconnection region resulting in an accelerated component, and entry through open field lines traditionally identified with the mantle source. The two entry mechanisms are separated in time, with the high-latitude reconnection region disappearing prior to <span class="hlt">substorm</span> onset.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19790059028&hterms=wind+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dwind%2Benergy','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19790059028&hterms=wind+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dwind%2Benergy"><span>Relationship between the <span class="hlt">growth</span> of the ring current and the interplanetary quantity. [solar wind energy-magnetospheric coupling parameter correlation with <span class="hlt">substorm</span> AE index</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Akasofu, S.-I.</p> <p>1979-01-01</p> <p>Akasofu (1979) has reported that the interplanetary parameter epsilon correlates reasonably well with the magnetospheric <span class="hlt">substorm</span> index AE; in the first approximation, epsilon represents the solar wind coupled to the magnetosphere. The correlation between the interplanetary parameter, the auroral electrojet index and the ring current index is examined for three magnetic storms. It is shown that when the interplanetary parameter exceeds the amount that can be dissipated by the ionosphere in terms of the Joule heat production, the excess energy is absorbed by the ring current belt, producing an abnormal <span class="hlt">growth</span> of the ring current index.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/960799','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/960799"><span>Observational evidence for an inside-out <span class="hlt">substorm</span> onset scenario</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Henderson, Michael G</p> <p>2008-01-01</p> <p>We present observations which provide strong support for a <span class="hlt">substorm</span> onset scenario in which a localized inner magnetospheric instability developed first and was later followed by the development of a Near Earth Neutral Line (NENL) farther down-tail. Specifically, we find that the onset began as a localized brightening of an intensified <span class="hlt">growth</span> <span class="hlt">phase</span> arc which developed as a periodic series of arc-aligned (i.e. azimuthally arrayed) bright spots. As the disturbance grew, it evolved into vortical structures that propagated poleward and eventually morphed into an east-west aligned arc system at the poleward edge of the auroral <span class="hlt">substorm</span> bulge. The auroral intensification shows an exponential <span class="hlt">growth</span> with an estimated e-folding time of around 188 seconds (linear <span class="hlt">growth</span> rate, {gamma} of 5.33 x 10{sup -3} s{sup -1}). During the initial breakup, no obvious distortions of auroral forms to the north were observed. However, during the expansion <span class="hlt">phase</span>, intensifications of the poleward boundary of the expanding bulge were observed together with the equatorward ejection of auroral streamers into the bulge. A strong particle injection was observed at geosynchronous orbit, but was delayed by several minutes relative to onsel. Ground magnetometer data also shows a two <span class="hlt">phase</span> development of mid-latitude positive H-bays, with a quasi-linear increase in H between the onset and the injection. We conclude that this event provides strong evidence in favor of the so-called 'inside-out' <span class="hlt">substorm</span> onset scenario in which the near Earth region activates first followed at a later time by the formation of a near-to-mid tail <span class="hlt">substorm</span> X-line. The ballooning instability is discussed as a likely mechanism for the initial onset.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoRL..43.4834C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoRL..43.4834C"><span><span class="hlt">Substorm</span> onset: A switch on the sequence of transport from decreasing entropy to increasing entropy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, C. X.</p> <p>2016-05-01</p> <p>In this study, we propose a scenario about the trigger for <span class="hlt">substorm</span> onset. In a stable magnetosphere, entropy is an increasing function tailward. However, in the <span class="hlt">growth</span> <span class="hlt">phase</span> of a <span class="hlt">substorm</span>, a later born bubble has lower entropy than earlier born bubbles. When a bubble arrives at its final destination in the near-Earth region, it will spread azimuthally because of its relatively uniform entropy. The magnetic flux tubes of a dying bubble, which cause the most equatorward aurora thin arc, would block the later coming bubble tailward of them, forming an unstable domain. Therefore, an interchange instability develops, which leads to the collapse of the unstable domain, followed by the collapse of the stretched plasma sheet. We regard the <span class="hlt">substorm</span> onset as a switch on the sequence of transport, i.e., from a decreasing entropy process to an increasing entropy process. We calculated the most unstable <span class="hlt">growth</span> rates and the wavelengths of instability, and both are in agreement with observations.</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('https://ntrs.nasa.gov/search.jsp?R=19950058922&hterms=flute&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dflute','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950058922&hterms=flute&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dflute"><span>Observations in the vicinity of <span class="hlt">substorm</span> onset: Implications for the substrom process</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Elphinstone, R. D.; Hearn, D. J.; Cogger, L. L.; Murphree, J. S.; Singer, H.; Sergeev, V.; Mursula, K.; Klumpar, D. M.; Reeves, G. D.; Johnson, M.</p> <p>1995-01-01</p> <p>Multi-instrument data sets from the ground and satellites at both low and high altitude have provided new results concerning <span class="hlt">substorm</span> onset and its source region in the magnetosphere. Twenty-six out of 37 <span class="hlt">substorm</span> onset events showed evidence of azimuthally spaced auroral forms (AAFs) prior to the explosive poleward motion associated with optical <span class="hlt">substorm</span> onset. AAFs can span 8 hours of local time prior to onset and generally propagate eastward in the morning sector. Onset itself is, however, more localized spanning only about 1 hour local time. AAF onset occur during time periods when the solar wind pressure is relatively high. AAFs brighten in conjunction with <span class="hlt">substorm</span> onset leading to the conclusion that they are a <span class="hlt">growth</span> <span class="hlt">phase</span> activity casually related to <span class="hlt">substorm</span> onset. Precursor activity associated with these AAFs is also seen near geosynchronous orbit altitude and examples show the relationship between the various instrumental definitions of <span class="hlt">substorm</span> onset. The implied mode number (30 to 135) derived from this work is inconsistent with cavity mode resonances but is consistent with a modified flute/ballooning instability which requires azimuthal pressure gradients. The extended source region and the distance to the open-closed field line region constrain reconnection theory and local mechanisms for <span class="hlt">substorm</span> onset. It is demonstrated that multiple onset <span class="hlt">substorms</span> can exist for which localized dipolarizations and the Pi 2 occur simultaneously with tail stretching existing elsewhere. These pseudobreakups can be initiated by auroral streamers which originate at the most poleward set of arc systems and drift to the more equatorward main UV oval. Observations are presented of these AAFs in conjunction with low- and high-altitutde particle and magnetic field data. These place the activations at the interface between dipolar and taillike field lines probably near the peak in the cross-tail current. These onsets are put in the context of a new scenario for <span class="hlt">substorm</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990063838&hterms=Monograph&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DMonograph','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990063838&hterms=Monograph&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DMonograph"><span>Origins and Transport of Ions during Magnetospheric <span class="hlt">Substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ashour-Abdalla, Maha; El-Alaoui, Mostafa; Peroomian, Vahe; Raeder, Joachim; Walker, Ray J.; Frank, L. A.; Paterson, W. R.</p> <p>1999-01-01</p> <p>We investigate the origins and the transport of ions observed in the near-Earth plasma sheet during the <span class="hlt">growth</span> and expansion <span class="hlt">phases</span> of a magnetospheric <span class="hlt">substorm</span> that occurred on November 24, 1996. Ions observed at Geotail were traced backward in time in time-dependent magnetic and electric fields to determine their origins and the acceleration mechanisms responsible for their energization. Results from this investigation indicate that, during the <span class="hlt">growth</span> <span class="hlt">phase</span> of the <span class="hlt">substorm</span>, most of the ions reaching Geotail had origins in the low latitude boundary layer (LLBL) and had alread@, entered the magnetosphere when the <span class="hlt">growth</span> <span class="hlt">phase</span> began. Late in the <span class="hlt">growth</span> <span class="hlt">phase</span> and in the expansion <span class="hlt">phase</span> a higher proportion of the ions reaching Geotail had their origin in the plasma mantle. Indeed, during the expansion <span class="hlt">phase</span> more than 90% of the ions seen by Geotail were from the mantle. The ions were accelerated enroute to the spacecraft; however, most of the ions' energy gain was achieved by non-adiabatic acceleration while crossing the equatorial current sheet just prior to their detection by Geotail. In general, the plasma mantle from both southern and northern hemispheres supplied non-adiabatic ions to Geotail, whereas the LLBL supplied mostly adiabatic ions to the distributions measured by the spacecraft.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GMS...216...99R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GMS...216...99R"><span>ULF Waves above the Nightside Auroral Oval during <span class="hlt">Substorm</span> Onset</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rae, I. J.; Watt, C. E. J.</p> <p>2016-02-01</p> <p>This chapter reviews historical ground-based observations of ultra-low-frequency (ULF) waves tied to <span class="hlt">substorms</span>, and highlights new research linking these ULF waves explicitly to <span class="hlt">substorm</span> onset itself. There are several robust methods that can be used to determine the characteristics of a nonstationary time series such as the ULF magnetic field traces observed in the auroral zone during <span class="hlt">substorms</span>. These include the pure state filter, the Hilbert-Huang transform, and wavelet analysis. The first indication of a <span class="hlt">substorm</span> is a sudden brightening of one of the quiet arcs lying in the midnight sector of the oval. The chapter focuses on the properties of ULF waves that are seen in two-dimensional images of auroral intensity near <span class="hlt">substorm</span> expansion <span class="hlt">phase</span> onset. It also discusses a wider range of magnetotail instabilities that could be responsible for the azimuthally structured auroral forms at <span class="hlt">substorm</span> onset.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020067784&hterms=IMF&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DIMF','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020067784&hterms=IMF&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DIMF"><span>Auroral <span class="hlt">Substorm</span> Time Scales: Seasonal and IMF Variations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chua, D.; Parks, G. K.; Brittnacher, M.; Germany, G. A.; Spann, J. F.; Six, N. Frank (Technical Monitor)</p> <p>2002-01-01</p> <p>The time scales and <span class="hlt">phases</span> of auroral <span class="hlt">substorm</span>, activity are quantied in this study using the hemispheric power computed from Polar Ultraviolet Imager (UVI) images. We have applied this technique to several hundred <span class="hlt">substorm</span> events and we are able to quantify how the characterist act, of <span class="hlt">substorms</span> vary with season and IMF Bz orientation. We show that <span class="hlt">substorm</span> time scales vary more strongly with season than with IMF Bz orientation. The recovery time for <span class="hlt">substorm</span>. activity is well ordered by whether or not the nightside oral zone is sunlit. The recovery time scales for <span class="hlt">substorms</span> occurring in the winter and equinox periods are similar and are both roughly a factor of two longer than in summer when the auroral oval is sunlit. Our results support the hypothesis that the ionosphere plays an active role in governing the dynamics of the aurora.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020067784&hterms=IMF&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DIMF','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020067784&hterms=IMF&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DIMF"><span>Auroral <span class="hlt">Substorm</span> Time Scales: Seasonal and IMF Variations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chua, D.; Parks, G. K.; Brittnacher, M.; Germany, G. A.; Spann, J. F.; Six, N. Frank (Technical Monitor)</p> <p>2002-01-01</p> <p>The time scales and <span class="hlt">phases</span> of auroral <span class="hlt">substorm</span>, activity are quantied in this study using the hemispheric power computed from Polar Ultraviolet Imager (UVI) images. We have applied this technique to several hundred <span class="hlt">substorm</span> events and we are able to quantify how the characterist act, of <span class="hlt">substorms</span> vary with season and IMF Bz orientation. We show that <span class="hlt">substorm</span> time scales vary more strongly with season than with IMF Bz orientation. The recovery time for <span class="hlt">substorm</span>. activity is well ordered by whether or not the nightside oral zone is sunlit. The recovery time scales for <span class="hlt">substorms</span> occurring in the winter and equinox periods are similar and are both roughly a factor of two longer than in summer when the auroral oval is sunlit. Our results support the hypothesis that the ionosphere plays an active role in governing the dynamics of the aurora.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JGRA..116.0I34T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JGRA..116.0I34T"><span>From space weather toward space climate time scales: <span class="hlt">Substorm</span> analysis from 1993 to 2008</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tanskanen, E. I.; Pulkkinen, T. I.; Viljanen, A.; Mursula, K.; Partamies, N.; Slavin, J. A.</p> <p>2011-05-01</p> <p>Magnetic activity in the Northern Hemisphere auroral region was examined during solar cycles 22 and 23 (1993-2008). <span class="hlt">Substorms</span> were identified from ground-based magnetic field measurements by an automated search engine. On average, 550 <span class="hlt">substorms</span> were observed per year, which gives in total about 9000 <span class="hlt">substorms</span>. The interannual, seasonal and solar cycle-to-cycle variations of the <span class="hlt">substorm</span> number (Rss), <span class="hlt">substorm</span> duration (Tss), and peak amplitude (Ass) were examined. The declining <span class="hlt">phases</span> of both solar cycles 22 and 23 were more active than the other solar cycle <span class="hlt">phases</span> due to the enhanced solar wind speed. The spring <span class="hlt">substorms</span> during the declining solar cycle <span class="hlt">phase</span> (∣Ass,decl∣ = 500 nT) were 25% larger than the spring <span class="hlt">substorms</span> during the ascending solar cycle years (∣Ass,acs∣ = 400 nT). The following seasonal variation was found: the most intense <span class="hlt">substorms</span> occurred during spring and fall, the largest <span class="hlt">substorm</span> frequency in the Northern Hemisphere winter, and the longest-duration <span class="hlt">substorms</span> in summer. Furthermore, we found a winter-summer asymmetry in the <span class="hlt">substorm</span> number and duration, which is speculated to be due to the variations in the ionospheric conductivity. The solar cycle-to-cycle variation was found in the yearly <span class="hlt">substorm</span> number and peak amplitude. The decline from the peak <span class="hlt">substorm</span> activity in 1994 and 2003 to the following minima took 3 years during solar cycle 22, while it took 6 years during solar cycle 23.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19960000800','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19960000800"><span>A mechanism for magnetospheric <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Erickson, G. M.; Heinemann, M.</p> <p>1994-01-01</p> <p>Energy-principle analysis performed on two-dimensional, self-consistent solutions for magnetospheric convection indicates that the magnetosphere is unstable to isobaric (yet still frozen-in) fluctuations of plasma-sheet flux tubes. Normally, pdV work associated with compression maintains stability of the inward/outward oscillating normal mode. However, if Earth's ionosphere can provide sufficient mass flux, isobaric expansion of flux tubes can occur. The <span class="hlt">growth</span> of a field-aligned potential drop in the near-Earth, midnight portion of the plasma sheet, associated with upward field-aligned currents responsible for the Harang discontinuity, redistributes plasma along field lines in a manner that destabilizes the normal mode. The <span class="hlt">growth</span> of this unstable mode results in an out-of-equilibrium situation near the inner edge. When this occurs over a downtail extent comparable to the half-thickness of the plasma sheet, collapse ensues and forces thinning of the plasma sheet whereby conditions favorable to reconnection occur. This scenario for <span class="hlt">substorm</span> onset is consistent with observed upward fluxes of ions, parallel potential drops, and observations of <span class="hlt">substorm</span> onset. These observations include near Earth onset, pseudobreakups, the <span class="hlt">substorm</span> current wedge, and local variations of plasma-sheet thickness.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/291130','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/291130"><span>New perspectives on <span class="hlt">substorm</span> injections</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Reeves, G.D.</p> <p>1998-12-01</p> <p>There has been significant progress in understanding <span class="hlt">substorm</span> injections since the Third International Conference on <span class="hlt">Substorms</span> in 1996. Progress has come from a combination of new theories, quantitative modeling, and observations--particularly multi-satellite observations. There is now mounting evidence that fast convective flows are the mechanism that directly couples <span class="hlt">substorm</span> processes in the mid tail, where reconnection occurs, with <span class="hlt">substorm</span> processes the inner magnetosphere where Pi2 pulsations, auroral breakups, and <span class="hlt">substorm</span> injections occur. This paper presents evidence that those flows combined with an earthward-propagating compressional wave are responsible for <span class="hlt">substorm</span> injections and discusses how that model can account for various <span class="hlt">substorm</span> injection signatures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM22A..05N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM22A..05N"><span><span class="hlt">Substorm</span> auroral onset triggering by flow-wave interaction detected with high-resolution radar and imager measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nishimura, T.; Lyons, L. R.; Zou, Y.; Bristow, W. A.; Hampton, D. L.; Nicolls, M. J.; Michell, R.; Samara, M.; Angelopoulos, V.; Donovan, E.; Spanswick, E.</p> <p>2013-12-01</p> <p>A critical, long-standing problem in <span class="hlt">substorm</span> research is identification of the sequence of events leading to <span class="hlt">substorm</span> auroral onset. THEMIS all-sky imager (ASI) array observations have revealed a repeatable pre-onset sequence that begins with a poleward boundary intensification (PBI) followed by a north-south oriented streamer moving equatorward. <span class="hlt">Substorm</span> auroral onset occurs soon after the streamer reaches near the <span class="hlt">substorm</span> onset location. Since fast magnetotail flows are linked to PBIs and streamers, this sequence indicates that onset is preceded by enhanced earthward plasma flows associated with a localized reconnection region near the pre-existing open-closed field line boundary. On the other hand, THEMIS satellite and ASIs also show that <span class="hlt">substorms</span> are preceded by azimuthally propagating waves of ~1-2 min periodicity, indicating that a wave mode within the near-Earth plasma sheet is important for triggering <span class="hlt">substorm</span> onset. However, it has been difficult to identify the link between fast earthward flows and these near-Earth waves. We have found a <span class="hlt">substorm</span> event for which there is excellent coverage from the Poker Flat incoherent scatter radar (PFISR), THEMIS white light and multi-spectral ASIs, where the auroral onset occurred within the PFISR field of view near the zenith of the ASIs. The <span class="hlt">substorm</span> onset was preceded by a PBI, and one of the radar beams going through the PBI detected equatorward flows and reaching the <span class="hlt">growth</span> <span class="hlt">phase</span> arc. The flows appear to propagate from open magnetic field lines across the open-closed boundary, leading to the PBI and then to onset soon after they reach the near-Earth plasma sheet. We also identified oscillations of auroral luminosity along the <span class="hlt">growth</span> <span class="hlt">phase</span> arc with a ~1 min period. These waves were propagating westward with only small intensity variations. Soon after the equatorward flows reached the <span class="hlt">growth</span> <span class="hlt">phase</span> arc, the wave luminosity amplified abruptly, denoting the onset of a <span class="hlt">substorm</span>. Based on this sequence, we suggest</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SSRv..190....1K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SSRv..190....1K"><span><span class="hlt">Substorm</span> Current Wedge Revisited</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kepko, L.; McPherron, R. L.; Amm, O.; Apatenkov, S.; Baumjohann, W.; Birn, J.; Lester, M.; Nakamura, R.; Pulkkinen, T. I.; Sergeev, V.</p> <p>2015-07-01</p> <p>Almost 40 years ago the concept of the <span class="hlt">substorm</span> current wedge was developed to explain the magnetic signatures observed on the ground and in geosynchronous orbit during <span class="hlt">substorm</span> expansion. In the ensuing decades new observations, including radar and low-altitude spacecraft, MHD simulations, and theoretical considerations have tremendously advanced our understanding of this system. The AMPTE/IRM, THEMIS and Cluster missions have added considerable observational knowledge, especially on the important role of fast flows in producing the stresses that generate the <span class="hlt">substorm</span> current wedge. Recent detailed, multi-spacecraft, multi-instrument observations both in the magnetosphere and in the ionosphere have brought a wealth of new information about the details of the temporal evolution and structure of the current system. While the large-scale picture remains valid, the new details call for revision and an update of the original view. In this paper we briefly review the historical development of the <span class="hlt">substorm</span> current wedge, review recent in situ and ground-based observations and theoretical work, and discuss the current active research areas. We conclude with a revised, time-dependent picture of the <span class="hlt">substorm</span> current wedge that follows its evolution from the initial <span class="hlt">substorm</span> flows through <span class="hlt">substorm</span> expansion and recovery.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20060009302&hterms=Khurana&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DA.%2BKhurana','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20060009302&hterms=Khurana&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DA.%2BKhurana"><span>The response of the near earth magnetotail to <span class="hlt">substorm</span> activity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kivelson, M. G.; McPherron, R. L.; Thompson, S.; Khurana, K. K.; Weygand, J. M.; Balogh, Andrew</p> <p>2005-01-01</p> <p>The large scale structure of the current sheet in the terrestrial magnetotail is often represented as the superposition of a constant northward-oriented magnetic field component (B(sub z)) and a component along the Earth-Sun direction (B(sub x)) that varies with distance from the center of the sheet (z(sub o) in GSM) as in a Hams neutral sheet. The latter implies that B(sub x) = B(sub Lx) tanh((z - z(sub o))/h) where B(sub Lx) is the magnitude of the B(sub x) component in the northern lobe. Correspondingly, the cross-tail current should be approximated by J(sub y) = (B(sub Lx)/h) sech(sup 2)((z - z(sub o))/h). Using data from the fluxgate magnetometer (FGM) on the Cluster I1 spacecraft tetrad, we have used measured fields and currents to ask if this model represents the large-scale properties of the system. During very quiet crossings of the plasmasheet, we find that the model gives a reasonable estimate of the trend of the average current and field distributions, but during disturbed intervals, the best fit fails to represent the data. If, however, the parameters z(sub o) and h of the model are taken as variable functions of time, the fits can be reasonably good. The temporal variation of the fit parameter h that characterizes the thickness of the current sheet can be interpreted in terms of thinning during the <span class="hlt">growth</span> <span class="hlt">phase</span> of a <span class="hlt">substorm</span> and thickening following the expansion <span class="hlt">phase</span>. Ground signatures that give insight into the local time of <span class="hlt">substorm</span> onset can be used to interpret the response of the plasmasheet to <span class="hlt">substorm</span> related changes of the global system. During a <span class="hlt">substorm</span>, the field magnitude in the central plasmasheet fluctuates at the period of Pi2 pulsations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110013272','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110013272"><span>THEMIS and <span class="hlt">Substorm</span> Timing</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sibeck, D. G.</p> <p>2010-01-01</p> <p>The THEMIS mission represents the culmination of many years of planning directed towards understanding the processes that drive and trigger geomagnetic <span class="hlt">substorms</span>. Following Akasofu's discovery of the <span class="hlt">substorm</span> cycle, it became increasingly clear that timing questions provide the key to discriminating between proposed 'inside-out' and 'outside-in' models for <span class="hlt">substorms</span>, triggered respectively by current disruption and magnetic reconnection. THEMIS observations provide a wealth of information that is currently being investigated to resolve this question. While observations in the magnetotail generally point towards reconnection. those on the ground point towards current disruption. This talk reviews the relevant observations and recent efforts at reconciliation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JGRA..118.3007C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JGRA..118.3007C"><span>Temporal and spatial dynamics of the regions 1 and 2 Birkeland currents during <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Clausen, L. B. N.; Baker, J. B. H.; Ruohoniemi, J. M.; Milan, S. E.; Coxon, J. C.; Wing, S.; Ohtani, S.; Anderson, B. J.</p> <p>2013-06-01</p> <p>We use current density data from the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) to identify the location of maximum region 1 current at all magnetic local times (MLTs). We term this location the R1 oval. Comparing the R1 oval location with particle precipitation boundaries identified in DMSP data, we find that the R1 oval is located on average within 1° of particle signatures associated with the open/closed field line boundary (OCB) across dayside and nightside MLTs. We hence conclude that the R1 oval can be used as a proxy for the location of the OCB. Studying the amount of magnetic flux enclosed by the R1 oval during the <span class="hlt">substorm</span> cycle, we find that the R1 oval flux is well organized by it: during the <span class="hlt">growth</span> <span class="hlt">phase</span> the R1 oval location moves equatorward as the amount of magnetic flux increases whereas after <span class="hlt">substorm</span> expansion <span class="hlt">phase</span> onset significant flux closure occurs as the R1 current location retreats to higher latitudes. For about 15 min after expansion <span class="hlt">phase</span> onset, the amount of open magnetic flux continues to increase indicating that dayside reconnection dominates over nightside reconnection. In the current density data, we find evidence of the <span class="hlt">substorm</span> current wedge and also show that the dayside R1 currents are stronger than their nightside counterpart during the <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phase</span>, whereas after expansion <span class="hlt">phase</span> onset, the nightside R1 currents dominate. Our observations of the current distribution and OCB movement during the <span class="hlt">substorm</span> cycle are in excellent agreement with the expanding/contracting polar cap paradigm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1711024O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1711024O"><span>Bursty reconnection modulating the <span class="hlt">substorm</span> current wedge, a <span class="hlt">substorm</span> case study re-analysed by ECLAT tools.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Opgenoorth, Hermann; Palin, Laurianne; Ågren, Karin; Zivkovic, Tatjana; Facsko, Gabor; Sergeev, Victor; Kubyshkina, Marina; Nikolaev, Alexander; Milan, Steve; Imber, Suzanne; Kauristie, Kirsti; Palmroth, Minna; van de Kamp, Max; Nakamura, Rumi; Boakes, Peter</p> <p>2015-04-01</p> <p>Multi-instrumental data mining and interpretation can be tedious and complicated. In this context, the ECLAT (European Cluster Assimilation Technology) project was created to « provide a novel and unique data base and tools for space scientists, by providing an upgrade of the European Space Agency's Cluster Active Archive (CAA). » How can this new tool help the space plasma physics community? Here we demonstrate the power of coordinated global and meso-scale ground-based data to put satellite data into the proper context. We re-analyse a well-isolated <span class="hlt">substorm</span> with a strong <span class="hlt">growth</span> <span class="hlt">phase</span>, which starts right overhead the Scandinavian network of instruments on 8 September 2002. This event was previously studied in detail by Sergeev et al (2005), based on a THEMIS-like configuration near-midnight using a unique radial constellation of LANL (~6.6Re), Geotail and Polar (~9Re), and Cluster (~16Re). In this new study we add detailed IMAGE spacecraft and ground-based network data. Magnetospheric models are specially adapted using solar wind conditions and in-situ observations. Simulation results are compared to the in-situ observations and discussed. We show how - both before and after <span class="hlt">substorm</span> onset - bursty reconnection in the tail modulates the localised field aligned current flow associated with the <span class="hlt">substorm</span> current wedge.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910036193&hterms=1983&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D1983','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910036193&hterms=1983&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D1983"><span>The <span class="hlt">substorm</span> event of 28 January 1983 - A detailed global study</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Baker, D. N.; Fairfield, D. H.; Slavin, J. A.; Richardson, I. G.; Craven, J. D.</p> <p>1990-01-01</p> <p>A comprehensive timeline of the <span class="hlt">growth</span>, expansion, and recovery <span class="hlt">phases</span> of a small isolated <span class="hlt">substorm</span> with an expansion <span class="hlt">phase</span> onset at 07:39 U.T. on January 28, 1983 is provided. The data sets examined include those from the electron-plasma, magnetometer, and energetic-particle instruments onboard ISEE-3. In addition to these data sets, a number of other spacecraft and ground-based data is utilized, including the magnetospheric energy-input rates evaluated in the upstream solar wind and imaging sequences used for examining auroral features during <span class="hlt">growth</span> and expansion <span class="hlt">phases</span>. <span class="hlt">Substorm</span> energy-input and -output relationships are estimated quantitatively, and the timing and physical dimensions of the distant tail disturbance implied by global observations available are evaluated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950011849&hterms=election&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Delection','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950011849&hterms=election&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Delection"><span>Energy dissipation in <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Weiss, Loretta A.; Reiff, P. H.; Moses, J. J.; Heelis, R. A.; Moore, B. D.</p> <p>1992-01-01</p> <p>The energy dissipated by <span class="hlt">substorms</span> manifested in several ways is discussed: the Joule dissipation in the ionosphere; the energization of the ring current by the injection of plasma sheet particles; auroral election and ion acceleration; plasmoid ejection; and plasma sheet ion heating during the recovery <span class="hlt">phase</span>. For each of these energy dissipation mechanisms, a 'rule of thumb' formula is given, and a typical dissipation rate and total energy expenditure is estimated. The total energy dissipated as Joule heat (approximately) 2 x 10(exp 15) is found about twice the ring current injection term, and may be even larger if small scale effects are included. The energy expended in auroral electron precipitation, on the other hand, is smaller than the Joule heating by a factor of five. The energy expended in refilling and heating the plasma sheets is estimated to be approximately 5 x 10(exp 14)J, while the energy lost due to plasmoid ejection is between (approximately) (10 exp 13)(exp 14)J.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950011849&hterms=Loretta&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DLoretta','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950011849&hterms=Loretta&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DLoretta"><span>Energy dissipation in <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Weiss, Loretta A.; Reiff, P. H.; Moses, J. J.; Heelis, R. A.; Moore, B. D.</p> <p>1992-01-01</p> <p>The energy dissipated by <span class="hlt">substorms</span> manifested in several ways is discussed: the Joule dissipation in the ionosphere; the energization of the ring current by the injection of plasma sheet particles; auroral election and ion acceleration; plasmoid ejection; and plasma sheet ion heating during the recovery <span class="hlt">phase</span>. For each of these energy dissipation mechanisms, a 'rule of thumb' formula is given, and a typical dissipation rate and total energy expenditure is estimated. The total energy dissipated as Joule heat (approximately) 2 x 10(exp 15) is found about twice the ring current injection term, and may be even larger if small scale effects are included. The energy expended in auroral electron precipitation, on the other hand, is smaller than the Joule heating by a factor of five. The energy expended in refilling and heating the plasma sheets is estimated to be approximately 5 x 10(exp 14)J, while the energy lost due to plasmoid ejection is between (approximately) (10 exp 13)(exp 14)J.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM23B2551F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM23B2551F"><span>Integrated Observations of ICME - Driven <span class="hlt">Substorm</span> - Storm Evolution on 7 August 1998: Traditional and Non-Traditional Aspects.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Farrugia, C. J.; Sandholt, P. E.; Torbert, R. B.</p> <p>2015-12-01</p> <p>The aim of this study is to obtain an integrated view of <span class="hlt">substorm</span>-storm evolution in relation to well-defined interplanetary (IP) conditions, and to identify traditional and non-traditional aspects of the DP1 and DP2 current systems during <span class="hlt">substorm</span> activity. Specifically, we report a case study of <span class="hlt">substorm</span>/storm evolution driven by an ICME from ground observations around the oval in relation to geoeffective IP parameters (Kan-Lee electric field, E-KL, and dynamic pressure, Pdyn), geomagnetic indices (AL, SYM-H and PCN) and satellite observations (from DMSP F13 and F14, Geotail, and GOES spacecraft). A sudden enhancement of E-KL at a southward turning of the IMF led to an initial transient <span class="hlt">phase</span> (PCN-enhancement) followed by a persistent stage of solar wind-magnetosphere-ionosphere coupling. The persistent <span class="hlt">phase</span> terminated abruptly at a steep E-KL reduction when the ICME magnetic field turned north after a 3-hour-long interval of enhanced E-KL. The persistent <span class="hlt">phase</span> consisted of (i) a 45-min-long <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phase</span> (DP2 current) followed by (ii) a classical <span class="hlt">substorm</span> onset (DP1 current) in the 0100 - 0300 MLT sector, (ii) a 30-min-long expansion <span class="hlt">phase</span>, maximizing in the same sector, and (iii) a <span class="hlt">phase</span> lasting for 1.5 hr of 10-15 min-long DP1 events in the 2100 - 2300 and 0400 - 0600 MLT sectors. In the morning sector the expansion <span class="hlt">phase</span> was characterized by Ps6 pulsations and omega bands. The SYM-H evolution reached the level of a major storm after a 2.5-hour-long interval of E-KL ˜5 mV/m and elevated Pdyn in the <span class="hlt">substorm</span> expansion <span class="hlt">phase</span>. Magetosphere - Ionosphere (M - I) coupling during a localized electrojet event at 0500 MLT in the late stage of the <span class="hlt">substorm</span> expansion is studied by ground - satellite conjunction data (Iceland - Geotail). The DP1 and DP2 components of geomagnetic activity are discussed in relation to M - I current systems and <span class="hlt">substorm</span> current wedge morphology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000024836','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000024836"><span>Energy Coupling Between the Ionosphere and Inner Magnetosphere Related to <span class="hlt">Substorm</span> Onset</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Maynard, Nelson C.</p> <p>1999-01-01</p> <p>The investigation of <span class="hlt">substorm</span> effects in the inner magnetosphere with CRRES data looked in detail at over 50 <span class="hlt">substorms</span> relative to signatures of onset and early expansion <span class="hlt">phases</span>. The accomplishments of the project are: Determined perpendicular Poynting flux at CRRES in the inner magnetosphere at <span class="hlt">substorm</span> onset, including primary direction is azimuthal, not radial, indicating a local source, no obvious signal from the magnetotail to trigger onset, strongly supports <span class="hlt">substorm</span> onset location near the inner edge of the plasma sheet and process is local and a strong function of Magnetosphere-ionosphere (MI) coupling. We also developed near geosynchronous onset (NGO) model for <span class="hlt">substorm</span> onset and expansion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730001666','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730001666"><span>Electron precipitation pattern and <span class="hlt">substorm</span> morphology</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hoffman, R. A.; Burch, J. L.</p> <p>1972-01-01</p> <p>Patterns of the precipitation of low energy electrons observed by polar satellites were examined as functions of <span class="hlt">substorm</span> <span class="hlt">phase</span>. Precipitation boundaries are generally identifiable at the low latitude edge of polar cusp electron precipitation and at the poleward edge of precipitation in the premidnight sector. Both of these boundaries move equatorward when the interplanetary magnetic field turns southward.</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://ntrs.nasa.gov/search.jsp?R=19900033691&hterms=magnitude&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dmagnitude','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900033691&hterms=magnitude&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dmagnitude"><span>On the relationship between the energetic particle flux morphology and the change in the magnetic field magnitude during <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lopez, R. E.; Lui, A. T. Y.; Sibeck, D. G.; Takahashi, K.; Mcentire, R. W.</p> <p>1989-01-01</p> <p>The relationship between the morphology of energetic particle <span class="hlt">substorm</span> injections and the change in the magnetic field magnitude over the course of the event is examined. Using the statistical relationships between the magnetic field during the <span class="hlt">growth</span> <span class="hlt">phase</span> and the change in the field magnitude during <span class="hlt">substorms</span> calculated by Lopez et al. (1988), a limited number of dispersionless ion injections observed by AMPTE CCE are selected. It is argued that this limited set is representative of a large set of events and that the conclusions drawn from examining those events are valid for <span class="hlt">substorms</span> in general in the inner magnetosphere. It is demonstrated that in an event when CCE directly observed the disruption of the current sheet, the particle and field data show that the region of particle acceleration was highly turbulent and was temporally, and perhaps spatially, limited and that the high fluxes of energetic particles are qualitatively associated with intense inductive electric fields.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910026438&hterms=wave+power&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dwave%2Bpower','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910026438&hterms=wave+power&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dwave%2Bpower"><span>Ultra-low-frequency wave power in the magnetotail lobes. I - Relation to <span class="hlt">substorm</span> onsets and the auroral electrojet index</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Smith, R. A.; Goertz, C. K.; Harrold, B. G.; Goldstein, M. L.; Lepping, R. P.; Fitch, C. A.; Sands, M. R.</p> <p>1990-01-01</p> <p>Time-series observations of the magnetotail-lobe magnetic field have been Fourier analyzed to compute the frequency-weighted energy density Pfz in the range 1-30 mHz. Pfz is generally observed in the range 0.0001-0.01 gamma-squared Hz with a mean value of 0.0012 during <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phases</span> and 0.001 in the comparison intervals. No strong correlation of Pfz is found with the auroral electrojet index in either set of intervals, but during <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phases</span> Pfz may vary by an order of magnitude over time scales of 30 min, with a tendency for higher power levels to occur later in the <span class="hlt">growth</span> <span class="hlt">phase</span>. Increases in Pfz precede by about 10 min localized expansive <span class="hlt">phase</span> activity observed in individual magnetograms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AnGeo..32...99M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AnGeo..32...99M"><span>Statistical visualization of the Earth's magnetotail and the implied mechanism of <span class="hlt">substorm</span> triggering based on superposed-epoch analysis of THEMIS data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Machida, S.; Miyashita, Y.; Ieda, A.; Nosé, M.; Angelopoulos, V.; McFadden, J. P.</p> <p>2014-02-01</p> <p>To investigate the physical mechanism responsible for <span class="hlt">substorm</span> triggering, we performed a superposed-epoch analysis using plasma and magnetic-field data from THEMIS probes. <span class="hlt">Substorm</span> onset timing was determined based on auroral breakups detected by all-sky imagers at the THEMIS ground-based observatories. We found earthward flows associated with north-south auroral streamers during the <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phase</span>. At around X = -12 Earth radii (RE), the northward magnetic field and its elevation angle decreased markedly approximately 4 min before <span class="hlt">substorm</span> onset. Moreover, a northward magnetic-field increase associated with pre-onset earthward flows was found at around X = -17 RE. This variation indicates that local dipolarization occurs. Interestingly, in the region earthwards of X = -18 RE, earthward flows in the central plasma sheet (CPS) reduced significantly approximately 3 min before <span class="hlt">substorm</span> onset, which was followed by a weakening of dawn-/duskward plasma-sheet boundary-layer flows (subject to a 1 min time lag). Subsequently, approximately 1 min before <span class="hlt">substorm</span> onset, earthward flows in the CPS were enhanced again and at the onset, tailward flows started at around X = -20 RE. Following <span class="hlt">substorm</span> onset, an increase in the northward magnetic field caused by dipolarization was found in the near-Earth region. Synthesizing these results, we confirm our previous results based on GEOTAIL data, which implied that significant variations start earlier than both current disruption and magnetic reconnection, at approximately 4 min before <span class="hlt">substorm</span> onset roughly halfway between the two regions of interest; i.e. in the catapult current sheet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..121.5213J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..121.5213J"><span>Multiradar observations of <span class="hlt">substorm</span>-driven ULF waves</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>James, M. K.; Yeoman, T. K.; Mager, P. N.; Klimushkin, D. Yu.</p> <p>2016-06-01</p> <p>A recent statistical study of ULF waves driven by <span class="hlt">substorm</span>-injected particles observed using Super Dual Auroral Radar Network (SuperDARN) found that the <span class="hlt">phase</span> characteristics of these waves varied depending on where the wave was observed relative to the <span class="hlt">substorm</span>. Typically, positive azimuthal wave numbers, m, were observed in waves generated to the east of the <span class="hlt">substorms</span> and negative m to the west. The magnitude of m typically increased with the azimuthal separation between the wave observation and the <span class="hlt">substorm</span> location. The energies estimated for the driving particles for these 83 wave events were found to be highest when the waves were observed closer to the <span class="hlt">substorm</span> and lowest farther away. Each of the 83 events studied by James et al. (2013) involved just a single wave observation per <span class="hlt">substorm</span>. Here a study of three individual <span class="hlt">substorm</span> events are presented, with associated observations of multiple ULF waves using various different SuperDARN radars. We demonstrate that a single <span class="hlt">substorm</span> is capable of driving a number of wave events characterized by different azimuthal scale lengths and wave periods, associated with different energies, W, in the driving particle population. We find that similar trends in m and W exist for multiple wave events with a single <span class="hlt">substorm</span> as was seen in the single wave events of James et al. (2013). The variety of wave periods present on similar L shells in this study may also be evidence for the detection of both poloidal Alfvén and drift compressional mode waves driven by <span class="hlt">substorm</span>-injected particles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006EOSTr..87..234K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006EOSTr..87..234K"><span>Storm-<span class="hlt">Substorm</span> Relations Workshop</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kan, Joe</p> <p>2006-06-01</p> <p>Magnetic storms in the magnetosphere can cause damage to communication satellites and large-scale power outages. The concept that a magnetic storm is a compilation of a series of <span class="hlt">substorms</span> was proposed by Akasofu [1968]. However, Kamide [1992] showed that <span class="hlt">substorms</span> are not a necessary condition for the occurrence of a magnetic storm. This controversy initiated a new era of research on the storm-<span class="hlt">substorm</span> relation, which was the subject of a recent workshop in Banff, Alberta, Canada. The main topics discussed during the meeting included a brief overview of what a <span class="hlt">substorm</span> is, how quasiperiodic <span class="hlt">substorm</span> events and steady magnetospheric convection (SMC) events without <span class="hlt">substorms</span> contribute to storms, and how plasma flows enhanced by magnetic reconnection in the plasma sheet contribute to <span class="hlt">substorms</span> and storms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6518763','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6518763"><span>Energy storage and dissipation in the magnetotail during <span class="hlt">substorms</span>. 1. Particle simulations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Winglee, R.M. ); Steinolfson, R.S. )</p> <p>1993-05-01</p> <p>The authors present a simulation study of the particle dynamics in the magnetotail during the development of <span class="hlt">substorms</span>. They look at how energy flows into the magnetotail under external magnetospheric conditions, and study the energy storage and dissipation in the magnetic field, and the role of particle dynamics in this process. They consider two primary external influences in their model. First is the pressure exerted by the magnetospheric boundary layer, on the nightside magnetopause. This pressure is expected to grow in response to solar wind penetration into the magnetosphere when the interplanetary magnetic field becomes southward in the initial <span class="hlt">phases</span> of <span class="hlt">substorm</span> <span class="hlt">growth</span>. Second is the dawn to dusk electric field. This field is expected to grow as the current sheet thins and energy stored in the magnetic field rises. The authors argue that the simultaneous increase in both the magnetic pressure and electric field can better model magnetotail response. One sees strong earthward flows in conjunction with increased energy storage in the tail, and at <span class="hlt">substorm</span> onset one sees the ejection of plasmoids in a tailward direction with increased particle heating. The clumping of particles in the current sheet due to the opposing effects of the magnetic pressure and electric field could be responsible for <span class="hlt">substorm</span> onset, rather than instabilities such as the tearing mode.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1918188O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1918188O"><span>Evolution of asymmetrically displaced footpoints during <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ohma, Anders; Østgaard, Nikolai; Reistad, Jone Peter; Tenfjord, Paul; Laundal, Karl M.; Snekvik, Kristian</p> <p>2017-04-01</p> <p>It is well established that a transverse (y) component in the interplanetary magnetic field (IMF) induces a By component in the closed magnetosphere through asymmetric loading and/or redistribution of magnetic flux. Simultaneous images of the aurora in the two hemispheres have revealed that conjugate auroral features are displaced longitudinally during such conditions, indicating that the field-lines are displaced from their symmetric configuration. Although the direction and magnitude of this displacement show correlations with IMF clock angle and dipole tilt, events show large temporal and spatial variability of this displacement. For instance, it is not clear how <span class="hlt">substorms</span> affect the displacement. In a previous case study, it has been demonstrated that displaced auroral forms, associated with the present IMF orientation, returned to a more symmetric configuration during the expansion <span class="hlt">phase</span> of two <span class="hlt">substorms</span>. Using IMAGE and Polar, we have identified several events where conjugate images during <span class="hlt">substorm</span> are available. We identify asymmetric auroral features during these events and investigate their time development during the <span class="hlt">substorm</span> <span class="hlt">phases</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM44A..01O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM44A..01O"><span>Current sheet thinning, reconnection onset, and auroral morphology during geomagnetic <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Otto, A.; Hsieh, M. S.</p> <p>2015-12-01</p> <p>Geomagnetic <span class="hlt">substorms</span> represent a fundamental energy release mechanism for the terrestrial magnetosphere. Specifically, the evolution of thin currents sheets during the <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phase</span> plays a key role for <span class="hlt">substorms</span> because such current sheets present a much lower threshold for the onset of tearing modes and magnetic reconnection than the usually thick magnetotail current sheet. Here we examine and compare two basic processes for current sheet thinning in the Earth's magnetotail: Current sheet thinning (1) through closed magnetic flux depletion (MFD) in the near Earth magnetotail caused by divergent flux transport to replace closed flux on the dayside and (2) through accumulation of open flux magnetic flux in the tail lobes also caused by dayside reconnection. Both processes are expected to operate during any period of enhanced dayside reconnection. It is demonstrated that closed magnetic flux depletion (MFD) in the near Earth magnetotail and the increase of open lobe magnetic flux can lead to the evolution of two separate thin current sheets in the near Earth and the mid tail regions of the magnetosphere. While the auroral morphology associated with MFD and near Earth current sheet formation is well consistent with typical <span class="hlt">substorm</span> <span class="hlt">growth</span> observation, midtail current sheet formation through lobe flux increase shows only a minor influence on the auroral ionosphere. We discuss the physics of the dual current sheet formation and local and auroral properties of magnetic reconnection in either current sheet. It is suggested that only reconnection onset in the near Earth current sheet may be consistent with <span class="hlt">substorm</span> expansion because the flux tube entropy depletion of mid tail reconnection appears insufficient to cause geosynchronous particle injection and dipolarization. Therefore reconnection in the mid tail current sheet is more likely associated with bursty bulk flows or dipolarization fronts which stop short of geosynchronous distances.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19890036843&hterms=Edmonton&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DEdmonton','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19890036843&hterms=Edmonton&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DEdmonton"><span>Boundary layer dynamics in the description of magnetospheric <span class="hlt">substorms</span></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.; Rostoker, G.; Frank, L. A.; Huang, C. Y.; Mitchell, D. G.</p> <p>1988-01-01</p> <p>This paper presents an analysis of eleven magnetospheric <span class="hlt">substorm</span> events for which good-quality ground-based magnetometer data and ISEE satellite data were both available. It is shown that the magnetotail particle and field observations associated with a <span class="hlt">substorm</span> expansive <span class="hlt">phase</span> can be explained through the spatial movement of the boundary layers and central plasma sheet in the magnetotail. The sweeping of these regions past the satellite, even in the absence of temporal variations within the various regions, can lead to a set of plasma flow observations typical of what is observed in the magnetotail during <span class="hlt">substorm</span> activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10149746','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10149746"><span><span class="hlt">Substorm</span> statistics: Occurrences and amplitudes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Borovsky, J.E.; Nemzek, R.J.</p> <p>1994-05-01</p> <p>The occurrences and amplitudes of <span class="hlt">substorms</span> are statistically investigated with the use of three data sets: the AL index, the Los Alamos 3-satellite geosynchronous energetic-electron measurements, and the GOES-5 and -6 geosynchronous magnetic-field measurements. The investigation utilizes {approximately} 13,800 <span class="hlt">substorms</span> in AL, {approximately} 1400 <span class="hlt">substorms</span> in the energetic-electron flux, and {approximately} 100 <span class="hlt">substorms</span> in the magnetic field. The rate of occurrence of <span class="hlt">substorms</span> is determined as a function of the time of day, the time of year, the amount of magnetotail bending, the orientation of the geomagnetic dipole, the toward/away configuration of the IMF, and the parameters of the solar wind. The relative roles of dayside reconnection and viscous coupling in the production of <span class="hlt">substorms</span> are assessed. Three amplitudes are defined for a <span class="hlt">substorms</span>: the jump in the AL index, the peak of the >30-keV integral electron flux at geosynchronous orbit near midnight, and the angle of rotation of the geosynchronous magnetic field near midnight. The <span class="hlt">substorm</span> amplitudes are statistically analyzed, the amplitude measurements are cross correlated with each other, and the <span class="hlt">substorm</span> amplitudes are determined as functions of the solar-wind parameters. Periodically occurring and randomly occurring <span class="hlt">substorms</span> are analyzed separately. The energetic-particle-flux amplitudes are consistent with unloading and the AL amplitudes are consistent with direct driving plus unloading.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014Ge%26Ae..54..575D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014Ge%26Ae..54..575D"><span>Polar and high latitude <span class="hlt">substorms</span> and solar wind conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Despirak, I. V.; Lyubchich, A. A.; Kleimenova, N. G.</p> <p>2014-09-01</p> <p>All <span class="hlt">substorm</span> disturbances observed in polar latitudes can be divided into two types: polar, which are observable at geomagnetic latitudes higher than 70° in the absence of <span class="hlt">substorms</span> below 70°, and high latitude <span class="hlt">substorms</span>, which travel from auroral (<70°) to polar (>70°) geomagnetic latitudes. The aim of this study is to compare conditions in the IMF and solar wind, under which these two types of <span class="hlt">substorms</span> are observable on the basis of data from meridional chain of magnetometers IMAGE and OMNI database for 1995, 2000, and 2006-2011. In total, 105 polar and 55 high latitude <span class="hlt">substorms</span> were studied. It is shown that polar <span class="hlt">substorms</span> are observable at a low velocity of solar wind after propagation of a high-speed recurrent stream during the late recovery <span class="hlt">phase</span> of a magnetic storm. High latitude <span class="hlt">substorms</span>, in contrast, are observable with a high velocity of solar wind, increased values of the Bz component of the IMF, the Ey component of the electric field, and solar wind temperature and pressure, when a high-speed recurrent stream passes by the Earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20120012572&hterms=time+space&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dtime%2Bspace','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20120012572&hterms=time+space&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dtime%2Bspace"><span>From Space Weather Toward Space Climate Time Scales: <span class="hlt">Substorm</span> Analysis from 1993 to 2008</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tanskanen, E. I.; Pulkkinen, T. I.; Viljanen, A.; Partamies, N.; Slavin, J. A.</p> <p>2011-01-01</p> <p>Magnetic activity in the Northern Hemisphere auroral region was examined during solar cycles 22 and 23 (1993- 2008). <span class="hlt">Substorms</span> were identified from ground-based magnetic field measurements by an automated search engine. On average, 550 <span class="hlt">substorms</span> were observed per year, which gives in total about 9000 <span class="hlt">substorms</span>. The interannual, seasonal and solar cycle-to-cycle variations of the <span class="hlt">substorm</span> number (R(sub ss)), <span class="hlt">substorm</span> duration (T(sub ss)), and peak amplitude (A(sub ss)) were examined. The declining <span class="hlt">phases</span> of both solar cycles 22 and 23 were more active than the other solar cycle <span class="hlt">phases</span> due to the enhanced solar wind speed. The spring <span class="hlt">substorms</span> during the declining solar cycle <span class="hlt">phase</span> (absolute value of A(sub ss,decl)) - 500 nT) were 25% larger than the spring <span class="hlt">substorms</span> during the ascending solar cycle years ((absolute value of A(sub ss,asc) = 400 nT). The following seasonal variation was found: the most intense <span class="hlt">substorms</span> occurred during spring and fall, the largest <span class="hlt">substorm</span> frequency in the Northern Hemisphere winter, and the longest-duration <span class="hlt">substorms</span> in summer. Furthermore, we found a winter-summer asymmetry in the <span class="hlt">substorm</span> number and duration. which is speculated to be due to the variations in the ionospheric conductivity. The solar cycle-Io-cycle variation was found in the yearly <span class="hlt">substorm</span> number and peak amplitude. The decline from the peak <span class="hlt">substorm</span> activity in 1994 and 2003 to the following minima took 3 years during solar cycle 22, while it took 6 years during solar cycle 23.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19990064362','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990064362"><span>The Origin of the Near-Earth Plasma Population During a <span class="hlt">Substorm</span> on November 24, 1996</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ashour-Abdalla, M.; El-Alaoui, M.; Peroomian, V.; Walker, R. J.; Raeder, J.; Frank, L. A.; Paterson, W. R.</p> <p>1999-01-01</p> <p>We investigate the origins and the transport of ions observed in the near-Earth plasma sheet during the <span class="hlt">growth</span> and expansion <span class="hlt">phases</span> of a magnetospheric <span class="hlt">substorm</span> that occurred on November 24, 1996. Ions observed at Geotail were traced backward in time in time-dependent magnetic and electric fields to determine their origins and the acceleration mechanisms responsible for their energization. Results from this investigation indicate that, during the <span class="hlt">growth</span> <span class="hlt">phase</span> of the <span class="hlt">substorm</span>, most of the ions reaching Geotail had origins in the low latitude boundary layer (LLBL) and had already entered the magnetosphere when the <span class="hlt">growth</span> <span class="hlt">phase</span> began. Late in the <span class="hlt">growth</span> <span class="hlt">phase</span> and in the expansion <span class="hlt">phase</span> a higher proportion of the ions reaching Geotail had their origin in the plasma mantle. Indeed, during the expansion <span class="hlt">phase</span> more than 90% of the ions seen by Geotail were from the mantle. The ions were accelerated enroute to the spacecraft; however, most of the ions' energy gain was achieved by non-adiabatic acceleration while crossing the equatorial current sheet just prior to their detection by Geotail. In general, the plasma mantle from both southern and northern hemispheres supplied non-adiabatic ions to Geotail, whereas the LLBL supplied mostly adiabatic ions to the distributions measured by the spacecraft. Distribution functions computed at the ion sources indicate that ionospheric ions reaching Geotail during the expansion <span class="hlt">phase</span> were significantly heated. Plasma mantle source distributions indicated the presence of a high-latitude reconnection region that allowed ion entry into the magnetosphere when the IMF was northward. These ions reached Geotail during the expansion <span class="hlt">phase</span>. Ions from the traditional plasma mantle had access to the spacecraft throughout the <span class="hlt">substorm</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750024910','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750024910"><span><span class="hlt">Substorms</span> on Mercury?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Siscoe, G. L.; Ness, N. F.; Yeates, C. M.</p> <p>1974-01-01</p> <p>Qualitative similarities between some of the variations in the Mercury encounter data and variations in the corresponding regions of the earth's magnetosphere during <span class="hlt">substorms</span> are pointed out. The Mariner 10 data on Mercury show a strong interaction between the solar wind and the plant similar to a scaled down version of that for the earth's magnetosphere. Some of the features observed in the night side Mercury magnetosphere suggest time dependent processes occurring there.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E3391T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E3391T"><span>Magnetic <span class="hlt">substorms</span> and northward IMF turning</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Troshichev, Oleg; Podorozhkina, Nataly</p> <p></p> <p>To determine the relation of the northward IMF turnings to <span class="hlt">substorm</span> sudden onsets, we separated all events with sharp northward IMF turnings observed in years of solar maximum (1999-2002) and solar minimum (2007-2008). The events (N=261) have been classified in 5 groups in accordance with average magnetic activity in auroral zone (low, moderate or high levels of AL index) at unchanged or slightly changed PC index and with dynamics of PC (steady distinct <span class="hlt">growth</span> or distinct decline) at arbitrary values of AL index. Statistical analysis of relationships between the IMF turning and changes of PC and AL indices has been fulfilled separately for each of 5 classes. Results of the analysis showed that, irrespective of geophysical conditions and solar activity epoch, the magnetic activity in the polar caps and in the auroral zone demonstrate no response to the sudden northward IMF turning, if the moment of northward turning is taken as a key date. Sharp increases of magnetic disturbance in the auroral zone are observed only under conditions of the growing PC index and statistically they are related to moment of the PC index exceeding the threshold level (~1.5 mV/m), not to northward turnings timed, as a rule, after the moment of sudden onset. Magnetic disturbances observed in these cases in the auroral zone (magnetic <span class="hlt">substorms</span>) are guided by behavior of the PC index, like to ordinary magnetic <span class="hlt">substorms</span> or <span class="hlt">substorms</span> developed under conditions of the prolonged northward IMF impact on the magnetosphere. The evident inconsistency between the sharp IMF changes measured outside of the magnetosphere and behavior of the ground-based PC index, the latter determining the <span class="hlt">substorm</span> development, provides an additional argument in favor of the PC index as a ground-based proxy of the solar wind energy that entered into magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA133898','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA133898"><span>Communications Magnetospheric <span class="hlt">Substorms</span>.</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1983-01-17</p> <p>increases with either an increase in solar wind velocity or a decrease in the angle of the interplanetary magnetic field with respect to the earth- sun ...symmetry produced by changes in the j orientation of the dipole with respect to the earth- sun line. Paper (46) showed very clearly that the synchronous field...57 (12), 993, 1976. - 36 - 34. Barfield, J.N. and R.1L. Mc:l’herron, MuItiple-synchrolous satellite observations of <span class="hlt">substorm</span>-associ’ated field- aliged</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19720058743&hterms=Whales&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DWhales','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19720058743&hterms=Whales&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DWhales"><span>Onset of magnetospheric <span class="hlt">substorms</span>.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tsurutani, B.; Bogott, F.</p> <p>1972-01-01</p> <p>An examination of the onset of magnetospheric <span class="hlt">substorms</span> is made by using ATS 5 energetic particles, conjugate balloon X rays and electric fields, all-sky camera photographs, and auroral-zone magnetograms. It is shown that plasma injection to ATS distances, conjugate 1- to 10-keV auroral particle precipitation, energetic electron precipitation, and enhancements of westward magnetospheric electric-field component all occur with the star of slowly developing negative magnetic bays. No trapped or precipitating energetic-particle features are seen at ATS 5 when later sharp negative magnetic-bay onsets occur at Churchill or Great Whale River.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/296782','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/296782"><span>Storm/<span class="hlt">substorm</span> signatures in the outer belt</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Korth, A.; Friedel, R.H.W.; Mouikis, C.; Fennell, J.F.</p> <p>1998-12-01</p> <p>The response of the ring current region is compared for periods of storm and <span class="hlt">substorm</span> activity, with an attempt to isolate the contributions of both processes. The authors investigate CRRES particle data in an overview format that allows the display of long-term variations of the outer radiation belt. They compare the evolution of the ring current population to indicators of storm (Dst) and <span class="hlt">substorm</span> (AE) activity and examine compositional changes. <span class="hlt">Substorm</span> activity leads to the intensification of the ring current at higher L (L {approximately} 6) and lower ring current energies compared to storms (L {approximately} 4). The O{sup +}/H{sup +} ratio during <span class="hlt">substorms</span> remains low, near 10%, but is much enhanced during storms (can exceed 100%). They conclude that repeated <span class="hlt">substorms</span> with an AE {approximately} 900 nT lead to a {Delta}Dst of {approximately} 30 nT, but do not contribute to Dst during storm main <span class="hlt">phase</span> as <span class="hlt">substorm</span> injections do not form a symmetric ring current during such disturbed times.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19..773G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19..773G"><span>The <span class="hlt">substorm</span> loading-unloading cycle as reproduced by community-available global MHD magnetospheric models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gordeev, Evgeny; Sergeev, Victor; Tsyganenko, Nikolay; Kuznetsova, Maria; Rastaetter, Lutz; Raeder, Joachim; Toth, Gabor; Lyon, John; Merkin, Vyacheslav; Wiltberger, Michael</p> <p>2017-04-01</p> <p>In this study we investigate how well the three community-available global MHD models, supported by the Community Coordinated Modeling Center (CCMC NASA), reproduce the global magnetospheric dynamics, including the loading-unloading <span class="hlt">substorm</span> cycle. We found that in terms of global magnetic flux transport CCMC models display systematically different response to idealized 2-hour north then 2-hour south IMF Bz variation. The LFM model shows a depressed return convection in the tail plasma sheet and high rate of magnetic flux loading into the lobes during the <span class="hlt">growth</span> <span class="hlt">phase</span>, as well as enhanced return convection and high unloading rate during the expansion <span class="hlt">phase</span>, with the amount of loaded/unloaded magnetotail flux and the <span class="hlt">growth</span> <span class="hlt">phase</span> duration being the closest to their observed empirical values during isolated <span class="hlt">substorms</span>. BATSRUS and Open GGCM models exhibit drastically different behavior. In the BATS-R-US model the plasma sheet convection shows a smooth transition to the steady convection regime after the IMF southward turning. In the Open GGCM a weak plasma sheet convection has comparable intensities during both the <span class="hlt">growth</span> <span class="hlt">phase</span> and the following slow unloading <span class="hlt">phase</span>. Our study shows that different CCMC models under the same solar wind conditions (north to south IMF variation) produce essentially different solutions in terms of global magnetospheric convection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980001901','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980001901"><span>Cross-field Current Instability for <span class="hlt">Substorm</span> Expansions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lui, Anthony</p> <p>1997-01-01</p> <p>The funding provided by the above-referenced NASA grant has enabled us: (1) to investigate the quasi-linear evolution of the IWI [Lui et al., 1993] and that of the generalized MTSI/IWI [Yoon and Lui, 1993], (2) to carry out the linear analysis of the LHDI to elucidate the difference between it and the MTSI/PM instability [Yoon et al., 1994], (3) to conduct some preliminary nonlocal analyses of the MTSI [Lui et al., 1995] and the IWI [Yoon and Lui, 1996] modes, (4) to study low-frequency shear-driven instability and its nonlinear evolution, which might compete with the CCI [Yoon et al., 1996], and (5) to study the evolution of current sheet during late <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phase</span> by means of 2-D Hall-MHD simulation in order to obtain a better understanding of the current sheet equilibrium crucial for CCI theory [Yoon and Lui, 1997].</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/2013Ge%26Ae..53..409B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013Ge%26Ae..53..409B"><span>Effect of magnetic storms (<span class="hlt">substorms</span>) on HF propagation: A review</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Blagoveshchenskii, D. V.</p> <p>2013-07-01</p> <p>The manifestations of the so-called main ionospheric effect during geomagnetic storms (<span class="hlt">substorms</span>) in the character of decameter-wave propagation are analyzed. On HF radio paths, the main effect is observed as variations in the signal amplitude and the MOF-LOF working frequency band similarly to the critical frequency of the ionospheric F2 layer. Specifically, these parameters increase before the disturbance active <span class="hlt">phase</span>, decrease during the active <span class="hlt">phase</span>, and increase again after this <span class="hlt">phase</span>. The propagation outside the great circle arc, the change in the propagation processes, and the HF radio noise behavior were also considered on these paths during storms (<span class="hlt">substorms</span>). It is assumed that the storm (<span class="hlt">substorm</span>) development onset can be predicted.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5131847','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5131847"><span>Magnetotail energy dissipation during an auroral <span class="hlt">substorm</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>Panov, E.V.; Baumjohann, W.; Wolf, R.A.; Nakamura, R.; Angelopoulos, V.; Weygand, J. M.; Kubyshkina, M.V.</p> <p>2016-01-01</p> <p>Violent releases of space plasma energy from the Earth’s magnetotail during <span class="hlt">substorms</span> produce strong electric currents and bright aurora. But what modulates these currents and aurora and controls dissipation of the energy released in the ionosphere? Using data from the THEMIS fleet of satellites and ground-based imagers and magnetometers, we show that plasma energy dissipation is controlled by field-aligned currents (FACs) produced and modulated during magnetotail topology change and oscillatory braking of fast plasma jets at 10-14 Earth radii in the nightside magnetosphere. FACs appear in regions where plasma sheet pressure and flux tube volume gradients are non-collinear. Faster tailward expansion of magnetotail dipolarization and subsequent slower inner plasma sheet restretching during <span class="hlt">substorm</span> expansion and recovery <span class="hlt">phases</span> cause faster poleward then slower equatorward movement of the <span class="hlt">substorm</span> aurora. Anharmonic radial plasma oscillations build up displaced current filaments and are responsible for discrete longitudinal auroral arcs that move equatorward at a velocity of about 1km/s. This observed auroral activity appears sufficient to dissipate the released energy. PMID:27917231</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.7541P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.7541P"><span>Magnetotail energy dissipation during an auroral <span class="hlt">substorm</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.; Baumjohann, Wolfgang; Wolf, Richard A.; Nakamura, Rumi; Angelopoulos, Vassilis; Weygand, James M.; Kubyshkina, Marina V.</p> <p>2017-04-01</p> <p>Violent releases of space plasma energy from the Earth's magnetotail during <span class="hlt">substorms</span> produce strong electric currents and bright aurora. But what modulates these currents and aurora and controls dissipation of the energy released in the ionosphere? Using data from the THEMIS fleet of satellites and ground-based imagers and magnetometers, we show that plasma energy dissipation is controlled by field-aligned currents (FACs) produced and modulated during magnetotail topology change and oscillatory braking of fast plasma jets at 10-14 Earth radii in the nightside magnetosphere. FACs appear in regions where plasma sheet pressure and flux tube volume gradients are non-collinear. Faster tailward expansion of magnetotail dipolarization and subsequent slower inner plasma sheet restretching during <span class="hlt">substorm</span> expansion and recovery <span class="hlt">phases</span> cause faster poleward then slower equatorward movement of the <span class="hlt">substorm</span> aurora. Anharmonic radial plasma oscillations build up displaced current filaments and are responsible for discrete longitudinal auroral arcs that move equatorward at a velocity of about 1 km s-1. This observed auroral activity appears sufficient to dissipate the released energy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27917231','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27917231"><span>Magnetotail energy dissipation during an auroral <span class="hlt">substorm</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Panov, E V; Baumjohann, W; Wolf, R A; Nakamura, R; Angelopoulos, V; Weygand, J M; Kubyshkina, M V</p> <p>2016-12-01</p> <p>Violent releases of space plasma energy from the Earth's magnetotail during <span class="hlt">substorms</span> produce strong electric currents and bright aurora. But what modulates these currents and aurora and controls dissipation of the energy released in the ionosphere? Using data from the THEMIS fleet of satellites and ground-based imagers and magnetometers, we show that plasma energy dissipation is controlled by field-aligned currents (FACs) produced and modulated during magnetotail topology change and oscillatory braking of fast plasma jets at 10-14 Earth radii in the nightside magnetosphere. FACs appear in regions where plasma sheet pressure and flux tube volume gradients are non-collinear. Faster tailward expansion of magnetotail dipolarization and subsequent slower inner plasma sheet restretching during <span class="hlt">substorm</span> expansion and recovery <span class="hlt">phases</span> cause faster poleward then slower equatorward movement of the <span class="hlt">substorm</span> aurora. Anharmonic radial plasma oscillations build up displaced current filaments and are responsible for discrete longitudinal auroral arcs that move equatorward at a velocity of about 1km/s. This observed auroral activity appears sufficient to dissipate the released energy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870053920&hterms=motion+distance&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dmotion%2Bdistance','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870053920&hterms=motion+distance&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dmotion%2Bdistance"><span>Latitudinal motions of the aurora during <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Craven, J. D.; Frank, L. A.</p> <p>1987-01-01</p> <p>Sequences of auroral images obtained with Dynamics Explorer 1 are used to investigate latitudinal motions of the aurora in <span class="hlt">substorms</span>. Average speeds of poleward motion are about 230 m/s near local midnight for two isolated, small <span class="hlt">substorms</span> and about 1000 m/s during an intensification within a previously active auroral oval. The speed of poleward expansion measured at about 6-min temporal resolution can differ greatly from the average speed because of the episodic development of <span class="hlt">substorms</span>. Recovery of the high-latitude boundary of the aurora to presubstorm latitudes is first observed in the postmidnight sector. In the premidnight sector the discrete aurora can become stationary for a period of time or even continue further poleward before a retreat to lower latitudes begins. During the recovery <span class="hlt">phase</span>, a prominent decrease in luminosities is first observed at intermediate latitudes within the auroral distribution. This region is bounded at higher latitudes by the discrete aurora and at lower latitudes by bright diffuse aurora. Given that magnetic field lines threading these auroral distributions map to the plasma sheet boundary layer and to the central plasma sheet, respectively, magnetic field lines at the intermediate auroral latitudes then map to the plasma sheet at distances of more than about 22 earth radii.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatPh..12.1158P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatPh..12.1158P"><span>Magnetotail energy dissipation during an auroral <span class="hlt">substorm</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, E. V.; Baumjohann, W.; Wolf, R. A.; Nakamura, R.; Angelopoulos, V.; Weygand, J. M.; Kubyshkina, M. V.</p> <p>2016-12-01</p> <p>Violent releases of space plasma energy from the Earth's magnetotail during <span class="hlt">substorms</span> produce strong electric currents and bright aurora. But what modulates these currents and aurora and controls dissipation of the energy released in the ionosphere? Using data from the THEMIS fleet of satellites and ground-based imagers and magnetometers, we show that plasma energy dissipation is controlled by field-aligned currents (FACs) produced and modulated during magnetotail topology change and oscillatory braking of fast plasma jets at 10-14 Earth radii in the nightside magnetosphere. FACs appear in regions where plasma sheet pressure and flux tube volume gradients are non-collinear. Faster tailward expansion of magnetotail dipolarization and subsequent slower inner plasma sheet restretching during <span class="hlt">substorm</span> expansion and recovery <span class="hlt">phases</span> cause faster poleward then slower equatorward movement of the <span class="hlt">substorm</span> aurora. Anharmonic radial plasma oscillations build up displaced current filaments and are responsible for discrete longitudinal auroral arcs that move equatorward at a velocity of about 1 km s-1. This observed auroral activity appears sufficient to dissipate the released energy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AnGeo..22.4165D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AnGeo..22.4165D"><span>Thinning and expansion of the <span class="hlt">substorm</span> plasma sheet: Cluster PEACE timing analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dewhurst, J.; Owen, C.; Fazakerley, A.; Balogh, A.</p> <p>2004-12-01</p> <p>The storage and subsequent removal of magnetic flux in the magnetotail during a geomagnetic <span class="hlt">substorm</span> has a dramatic effect on the thickness of the cross-tail plasma sheet. The near-Earth plasma sheet is thought to thin during the <span class="hlt">growth</span> <span class="hlt">phase</span> and then rapidly expand after onset of the <span class="hlt">substorm</span>. The direction of propagation, whether earthward or tailward along the GSM-X direction in the near-Earth tail, may suggest the time ordering of current-disruption and near-Earth reconnection, both of which are key to the <span class="hlt">substorm</span> process. Cluster's Plasma Electron And Current Experiment (PEACE) allows 4-point observations of electrons at the plasma sheet - lobe boundary as this interface passes over the Cluster tetrahedron. The relative timings of the boundary passage at each spacecraft allow a determination of this boundary's speed and direction of motion, assuming this is planar on the scale of the Cluster separation scale. For those boundaries corresponding to the expansion of the plasma sheet, this direction is fundamental to determining the direction of expansion. We present an example of isolated thinning and expansion of the plasma sheet, as well as a multiple thinning-expansion event that occurs during a more active <span class="hlt">substorm</span>. Data from the 2001 and 2002 tail passes have been analysed and the average plasma sheet - lobe boundary normal vectors and normal component velocities have been calculated. A total of 77 crossings, typically between 10 and 20 RE downtail, correspond to <span class="hlt">substorm</span> associated expansion of the plasma sheet over the spacecraft. These had normal vectors predominantly in the GSM-YZ plane and provided no clear evidence for the formation of the near-Earth neutral line occurring before current disruption or vice versa. The expansions of the plasma sheet generally exhibit the appropriate GSM-Z direction expected for the given lobe, and tend to have GSM-Y components that support onset occurring near the origin of the GSM-YZ plane. This result is noteworthy in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810059602&hterms=Chestnut&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DChestnut','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810059602&hterms=Chestnut&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DChestnut"><span>Propagating <span class="hlt">substorm</span> injection fronts</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Moore, T. E.; Arnoldy, R. L.; Feynman, J.; Hardy, D. A.</p> <p>1981-01-01</p> <p>It is argued that a series of two-satellite observations leads to a clarification of <span class="hlt">substorm</span> plasma injection, in which boundary motion plays a major role. Emphasis is put on a type of event characterized by abrupt, dispersionless changes in electron intensity and a coincident perturbation that consists of both a field magnitude increase and a small rotation toward more dipolar orientation. Comparing plasma observations at two points, it is found that in active, preinjection conditions the two most important features of the plasma sheet are: (1) the low-energy convection boundary for near-zero energy particles, determined by the magnitude of the large-scale convection electric field; and (2) the precipitation-flow boundary layer between the hot plasma sheet and the atmospherically contaminated inner plasma sheet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EOSTr..91..335K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EOSTr..91..335K"><span>A Bright Future for <span class="hlt">Substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kissinger, J.; McPherron, R. L.</p> <p>2010-09-01</p> <p>Tenth International Conference on <span class="hlt">Substorms</span>; San Luis Obispo, California, 22-26 March 2010; Intense auroral displays are caused by <span class="hlt">substorms</span>, events in the Earth's magnetosphere consisting of an abundance of plasma physics processes. More than 120 scientists gathered to discuss the latest findings on this phenomenon at a conference organized by Vassilis Angelopoulos, Larry R. Lyons, and Robert L. McPherron of the University of California, Los Angeles. Just as a thunderstorm cannot be properly analyzed with a single weather station, <span class="hlt">substorms</span> cannot be properly studied with a single satellite in the vastness of space. Recent satellite missions now provide several simultaneous observations of key processes. Extensive networks of ionospheric radars, magnetometers, and all-sky imagers extend around the world. This has resulted in unprecedented coverage and conjunctions, brightening scientists' understanding of <span class="hlt">substorms</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140002251','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140002251"><span>Global Simulation of Proton Precipitation Due to Field Line Curvature During <span class="hlt">Substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gilson, M. L.; Raeder, J.; Donovan, E.; Ge, Y. S.; Kepko, L.</p> <p>2012-01-01</p> <p>The low latitude boundary of the proton aurora (known as the Isotropy Boundary or IB) marks an important boundary between empty and full downgoing loss cones. There is significant evidence that the IB maps to a region in the magnetosphere where the ion gyroradius becomes comparable to the local field line curvature. However, the location of the IB in the magnetosphere remains in question. In this paper, we show simulated proton precipitation derived from the Field Line Curvature (FLC) model of proton scattering and a global magnetohydrodynamic simulation during two <span class="hlt">substorms</span>. The simulated proton precipitation drifts equatorward during the <span class="hlt">growth</span> <span class="hlt">phase</span>, intensifies at onset and reproduces the azimuthal splitting published in previous studies. In the simulation, the pre-onset IB maps to 7-8 RE for the <span class="hlt">substorms</span> presented and the azimuthal splitting is caused by the development of the <span class="hlt">substorm</span> current wedge. The simulation also demonstrates that the central plasma sheet temperature can significantly influence when and where the azimuthal splitting takes place.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA.....8968Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA.....8968Z"><span>DR-current intensity variations during <span class="hlt">substorm</span> development</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zaitseva, S. A.; Drobinina, T. A.; Pudovkin, M. I.</p> <p>2003-04-01</p> <p>According to the concept dominated by the last time, the intensification of the DR-current takes place during the polar <span class="hlt">substorm</span> development. In the recent papers Iyemori and Rao claim that geomagnetic storms and <span class="hlt">substorms</span> are independent processes, and SYM-index (essentially the same as Dst-index) tends to decay after the onset of <span class="hlt">substorms</span>. In this paper we tried to clear up the cause of this contradiction by studying the connection of ring current development with polar <span class="hlt">substorms</span> basing on the new data: ASY-, SYM-indices describing asymmetric and symmetric parts of DR-current correspondingly and AL-index as a measure of polar disturbances. It is shown that the hourly-mean SYM- and ASY-indices correlate with AL-index (r=0.63 and 0.69 correspondingly), and the connection between these values becomes worse for strong storms. Besides, at the <span class="hlt">substorm</span> expansive <span class="hlt">phase</span> onset, the energy can put mainly to the asymmetric part rather than into symmetric part of DR-current. Empirical Q-index based on solar wind parameters describes the energy input into DR-current; Q correlates rather well with SYM, ASY and AL-indices. Thus the intensifications of polar disturbances and DR-current take place simultaneously and have the same source.At the same time, the proportion in which the solar wind energy is distributed between the DR-current, polar ionosphere and magnetotail depends on the Dst variation <span class="hlt">phase</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015TESS....120603K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015TESS....120603K"><span>The <span class="hlt">Substorm</span> Current Wedge Revisited</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kepko, Larry; McPherron, Robert; Apatenkov, Sergey; Baumjohann, Wolfgang; Birn, Joachim; Lester, Mark; Nakamura, Rumi; Pulkkinen, Tuija; Sergeev, Victor</p> <p>2015-04-01</p> <p>Almost 40 years ago the concept of the <span class="hlt">substorm</span> current wedge was developed to explain the magnetic signatures observed on the ground and in geosynchronous orbit during <span class="hlt">substorm</span> expansion. In the ensuing decades new observations, including radar and low-altitude spacecraft, MHD simulations, and theoretical considerations have tremendously advanced our understanding of this system. The AMPTE/IRM, THEMIS and Cluster missions have added considerable observational knowledge, especially on the important role of fast flows in producing the stresses that generate the <span class="hlt">substorm</span> current wedge. Recent detailed, multi-spacecraft, multi-instrument observations both in the magnetosphere and in the ionosphere have brought a wealth of new information about the details of the temporal evolution and structure of the current system. In this paper, we briefly review recent in situ and ground-based observations and theoretical work that have demonstrated a need for an update of the original picture. We present a revised, time-dependent picture of the <span class="hlt">substorm</span> current wedge that follows its evolution from the initial <span class="hlt">substorm</span> flows through <span class="hlt">substorm</span> expansion and recovery, and conclude by identifying open questions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19770018765','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19770018765"><span>Relationship between auroral <span class="hlt">substorms</span> and the occurrence of terrestrial kilometric radiation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kaiser, M. L.; Alexander, J. K.</p> <p>1977-01-01</p> <p>The correlation between magnetospheric <span class="hlt">substorms</span> as inferred from the AE(11) index and the occurrence of terrestrial kilometric radiation (TKR) is examined. It is found that AE and TKR are well correlated when observations are made from above the 15-03 hr local time zone and are rather poorly correlated over the 03-15 hr zone. High-resolution dynamic spectra obtained during periods of isolated <span class="hlt">substorms</span> indicate that low-intensity, high-frequency TKR commences at about the same time as the <span class="hlt">substorm</span> <span class="hlt">phase</span>. The <span class="hlt">substorm</span> expansion <span class="hlt">phase</span> corresponds to a rapid intensification and bandwidth increase of TKR. When combined with previous results, these new observations imply that many TKR events begin at low altitudes and high frequencies (about 400-500 kHz) and spread to higher altitudes and lower frequencies as the <span class="hlt">substorm</span> expands.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19720027222&hterms=Recovery+workers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DRecovery%2Bworkers','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19720027222&hterms=Recovery+workers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DRecovery%2Bworkers"><span>Magnetospheric <span class="hlt">substorms</span> in the distant magnetotail observed by Imp 3.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Meng, C. I.; Akasofu, S.; Kawasaki, K.; Hones, E. W., Jr.</p> <p>1971-01-01</p> <p>Study of variations of the magnetic field and plasma sheet in the distant magnetotail (20 to 40 earth radii) during magnetospheric <span class="hlt">substorms</span> on the basis of the Imp 3 magnetic-field and particle data. Depending on the locations of the satellite with respect to the boundary of the plasma sheet, the variations differ greatly. However, the present results and the results of other workers give a clear indication of an increase of the magnitude of the field outside the plasma sheet and of the simultaneous ?thinning' of the plasma sheet during an early <span class="hlt">phase</span> of <span class="hlt">substorms</span>. At about the maximum epoch or during the recovery <span class="hlt">phase</span> of <span class="hlt">substorms</span>, the plasma sheet expands and appears to be inflated to at least the presubstorm level. Furthermore, a large excessive flux of the magnetic (approximately equal to Z component) field, as compared with the flux of the original dipole field, appears across the neutral sheet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19720027222&hterms=kawasaki&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dkawasaki','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19720027222&hterms=kawasaki&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dkawasaki"><span>Magnetospheric <span class="hlt">substorms</span> in the distant magnetotail observed by Imp 3.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Meng, C. I.; Akasofu, S.; Kawasaki, K.; Hones, E. W., Jr.</p> <p>1971-01-01</p> <p>Study of variations of the magnetic field and plasma sheet in the distant magnetotail (20 to 40 earth radii) during magnetospheric <span class="hlt">substorms</span> on the basis of the Imp 3 magnetic-field and particle data. Depending on the locations of the satellite with respect to the boundary of the plasma sheet, the variations differ greatly. However, the present results and the results of other workers give a clear indication of an increase of the magnitude of the field outside the plasma sheet and of the simultaneous ?thinning' of the plasma sheet during an early <span class="hlt">phase</span> of <span class="hlt">substorms</span>. At about the maximum epoch or during the recovery <span class="hlt">phase</span> of <span class="hlt">substorms</span>, the plasma sheet expands and appears to be inflated to at least the presubstorm level. Furthermore, a large excessive flux of the magnetic (approximately equal to Z component) field, as compared with the flux of the original dipole field, appears across the neutral sheet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFMSM52B..08E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFMSM52B..08E"><span>Is the Current Disruption Region the Genesis Region for the <span class="hlt">Substorm</span> X-Line?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Erickson, G. M.; Maynard, N. C.; Wilson, G. R.</p> <p>2002-12-01</p> <p>The nominal location for the <span class="hlt">substorm</span> near-Earth X-line (NEXL) has been found to be outside but near 20RE in the tail. The modified Near-Earth Neutral Line (NENL) model postulates that braking of fast, earthward flows and pile up of magnetic flux accounts for the initiation of the <span class="hlt">substorm</span> current wedge and dipolarization within 10RE, and its tailward expansion. Current disruption (CD) and CD-like magnetic activity accompanies dipolarization in the 8--12RE range and commences in close temporal proximity to auroral onset. We report here, based on Geotail observations, that 70% of CD-like activity in the 9 (perigee) to 12 RE range of the pre-midnight and midnight plasma sheet begins in the absence of earthward flow. In only 20% of the cases does CD-like activity start coincident with arrival of earthward flow. Indeed, in a like number of cases, CD-like activity starts coincident with a clear signal (tailward Poynting flux) arriving from nearer Earth. When auroral coverage is adequate, we have shown that these <span class="hlt">substorms</span> proceed in two stages, with reconnection occurring during the second stage. But this is not the entire story. We note three pieces of evidence that lead us to suggest that the CD region is the genesis region for the NEXL. (1) In 10% of CD-like events, magnetic fluctuations commence like typical CD events, but rather than dipolarizing, the magnetic field diminishes. Whereas the distribution for the typical CD signature shows a strong peak near 10RE, these hybrid events are more uniformly distributed between 9 and 19 RE, and from 13--19RE represent 30% of all CD-like activity. (2) Signatures of a <span class="hlt">substorm</span> NEXL earthward of Geotail can be found as near Earth as 13RE on occasion. (3) A minimum in equatorial magnetic field strength is believed to evolve during the <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phase</span> near 10RE. Hau and Wolf [JGR, 92, 4745, 1987] discuss how, in the presence of resistivity, the B-minimum structure diffuses tailward, and the minimum deepens, until a NEXL</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950029532&hterms=energy+participation&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Denergy%2Bparticipation','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950029532&hterms=energy+participation&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Denergy%2Bparticipation"><span>Energy density of ionospheric and solar wind origin ions in the near-Earth magnetotail during <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Daglis, Loannis A.; Livi, Stefano; Sarris, Emmanuel T.; Wilken, Berend</p> <p>1994-01-01</p> <p>Comprehensive energy density studies provide an important measure of the participation of various sources in energization processes and have been relatively rare in the literature. We present a statistical study of the energy density of the near-Earth magnetotail major ions (H(+), O(+), He(++), He(+)) during <span class="hlt">substorm</span> expansion <span class="hlt">phase</span> and discuss its implications for the solar wind/magnetosphere/ionosphere coupling. Our aim is to examine the relation between auroral activity and the particle energization during <span class="hlt">substorms</span> through the correlation between the AE indices and the energy density of the major magnetospheric ions. The data we used here were collected by the charge-energy-mass (CHEM) spectrometer on board the Active Magnetospheric Particle Trace Explorer (AMPTE)/Charge Composition Explorer (CCE) satellite in the near-equatorial nightside magnetosphere, at geocentric distances approximately 7 to 9 R(sub E). CHEM provided the opportunity to conduct the first statistical study of energy density in the near-Earth magnetotail with multispecies particle data extending into the higher energy range (greater than or equal to 20 keV/E). the use of 1-min AE indices in this study should be emphasized, as the use (in previous statistical studies) of the (3-hour) Kp index or of long-time averages of AE indices essentially smoothed out all the information on <span class="hlt">substorms</span>. Most distinct feature of our study is the excellent correlation of O(+) energy density with the AE index, in contrast with the remarkably poor He(++) energy density - AE index correlation. Furthermore, we examined the relation of the ion energy density to the electrojet activity during <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phase</span>. The O(+) energy density is strongly correlated with the pre-onset AU index, that is the eastward electrojet intensity, which represents the <span class="hlt">growth</span> <span class="hlt">phase</span> current system. Our investigation shows that the near-Earth magnetotail is increasingly fed with energetic ionospheric ions during periods of enhanced</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950029532&hterms=earth+hour&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dearth%2Bhour','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950029532&hterms=earth+hour&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dearth%2Bhour"><span>Energy density of ionospheric and solar wind origin ions in the near-Earth magnetotail during <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Daglis, Loannis A.; Livi, Stefano; Sarris, Emmanuel T.; Wilken, Berend</p> <p>1994-01-01</p> <p>Comprehensive energy density studies provide an important measure of the participation of various sources in energization processes and have been relatively rare in the literature. We present a statistical study of the energy density of the near-Earth magnetotail major ions (H(+), O(+), He(++), He(+)) during <span class="hlt">substorm</span> expansion <span class="hlt">phase</span> and discuss its implications for the solar wind/magnetosphere/ionosphere coupling. Our aim is to examine the relation between auroral activity and the particle energization during <span class="hlt">substorms</span> through the correlation between the AE indices and the energy density of the major magnetospheric ions. The data we used here were collected by the charge-energy-mass (CHEM) spectrometer on board the Active Magnetospheric Particle Trace Explorer (AMPTE)/Charge Composition Explorer (CCE) satellite in the near-equatorial nightside magnetosphere, at geocentric distances approximately 7 to 9 R(sub E). CHEM provided the opportunity to conduct the first statistical study of energy density in the near-Earth magnetotail with multispecies particle data extending into the higher energy range (greater than or equal to 20 keV/E). the use of 1-min AE indices in this study should be emphasized, as the use (in previous statistical studies) of the (3-hour) Kp index or of long-time averages of AE indices essentially smoothed out all the information on <span class="hlt">substorms</span>. Most distinct feature of our study is the excellent correlation of O(+) energy density with the AE index, in contrast with the remarkably poor He(++) energy density - AE index correlation. Furthermore, we examined the relation of the ion energy density to the electrojet activity during <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phase</span>. The O(+) energy density is strongly correlated with the pre-onset AU index, that is the eastward electrojet intensity, which represents the <span class="hlt">growth</span> <span class="hlt">phase</span> current system. Our investigation shows that the near-Earth magnetotail is increasingly fed with energetic ionospheric ions during periods of enhanced</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/14387','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/14387"><span>Kinetic Ballooning Instability as a <span class="hlt">Substorm</span> Onset Mechanism</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>C.Z.Cheng</p> <p>1999-10-01</p> <p>A new scenario of <span class="hlt">substorm</span> onset and current disruption and the corresponding physical processes are presented based on the AMPTE/CCE spacecraft observation and a kinetic ballooning instability theory. During the <span class="hlt">growth</span> <span class="hlt">phase</span> of <span class="hlt">substorms</span> the plasma beta is larger than unity (20 greater than or equal to beta greater than or equal to 1). Toward the end of the late <span class="hlt">growth</span> <span class="hlt">phase</span> the plasma beta increases from 20 to greater than or equal to 50 in approximately 3 minutes and a low-frequency instability with a wave period of 50 - 75 sec is excited and grows exponentially to a large amplitude at the current disruption onset. At the onset, higher-frequency instabilities are excited so that the plasma and electromagnetic field form a turbulent state. Plasma transport takes place to modify the ambient pressure profile so that the ambient magnetic field recovers from a tail-like geometry to a dipole-like geometry. A kinetic ballooning instability (KBI) theory is proposed to explain the low-frequency instability (frequency and <span class="hlt">growth</span> rate) and its observed high beta threshold (beta subscript c is greater than or equal to 50). Based on the ideal-MHD theory beta subscript c, superscript MHD approximately equals 1 and the ballooning modes are predicted to be unstable during the <span class="hlt">growth</span> <span class="hlt">phase</span>, which is inconsistent with observation that no appreciable magnetic field fluctuation is observed. The enhancement beta subscript c over beta subscript c, superscript MHD is due to the kinetic effects of trapped electrons and finite ion-Larmor radii which provide a large stabilizing effect by producing a large parallel electric field and hence a parallel current that greatly enhances the stabilizing effect of field line tension. As a result, beta subscript c is greatly increased over beta subscript c, superscript MHD by a factor proportional to the ratio of the total electron density to the untrapped electron density (n subscript e divided by n subscript eu) which is greater than or equal to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950029539&hterms=1054&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2526%25231054','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950029539&hterms=1054&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2526%25231054"><span>Thin current sheets in the magnetotail during <span class="hlt">substorms</span>: CDAW 6 revisited</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pulkkinen, T. I.; Baker, D. N.; Mitchell, D. G.; Mcpherron, R. L.; Huang, C. Y.; Frank, L. A.</p> <p>1994-01-01</p> <p>The global magnetic field configuration during the <span class="hlt">growth</span> <span class="hlt">phase</span> of the Coordinated Data Analysis Workshop (CDAW) 6 <span class="hlt">substorm</span> (March 22, 1979, 1054 UT) is modeled using data from two suitably located spacecraft and temporally evolving variations of the Tsyganenko magnetic field model. These results are compared with a local calculation of the current sheet location and thickness carried out by McPherron et al. (1987) and Sanny et al. (this issue). Both models suggest that during the <span class="hlt">growth</span> <span class="hlt">phase</span> the current sheet rotated away from its nominal location, and simultaneously thinned strongly. The locations and thickness obtained from the two models are in good agreement. The global model suggests that the peak current density is approximately 120 nA/sq m and that the cross-tail current almost doubled its intensity during this very strong <span class="hlt">growth</span> <span class="hlt">phase</span>. The global model predicts a field configuration that is sufficiently stretched to scatter thermal electrons, which may be conducive to the onset of ion tearing in the tail. The electron plasma data further support this scenario, as the anisotropy present in the low-energy electrons disappears close to the <span class="hlt">substorm</span> onset. The electron contribution to the intensifying current in this case is of the order of 10% before the isotropization of the distribution.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1914406T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1914406T"><span>Alfvénic solar wind powers <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tanskanen, Eija; Hynönen, Reko; Mursula, Kalevi</p> <p>2017-04-01</p> <p>Alfvenic solar wind fluctuations (ALFs) are known to modulate geomagnetic activity. We have examined high-latitude geomagnetic activity over the solar cycle 23 and found out that increase of solar wind Alfvenicity enhance both auroral <span class="hlt">substorm</span> intensity and <span class="hlt">substorm</span> frequency. Alfvénic solar wind fluctuations are found throughout the solar cycle, but they are fastest, most frequent and geo-effective in the declining <span class="hlt">phase</span> of the cycle, when the number of high-speed streams at the Earth's vicinity increases rapidly. We find a rapid transition from the predominance of slow (< 400 km/s) ALFs in 2002 to fast (> 600 km/s) ALFs in 2003, in coincidence with the rapid increase of <span class="hlt">substorm</span> activity from late 2002 to early 2003. The Alfvénicity of solar wind increased by 40% from 2002 to 2003. After the transition the fast ALFs occur twice per solar rotation while in previous year only four fast ALF intervals were detected. Increase of solar wind Alfvénicity by 40% from 2002 to 2003, and transition from slow to fast Alfvén fluctuations coincide with the increase of auroral <span class="hlt">substorm</span> intensity by 28% and <span class="hlt">substorm</span> frequency by 43%.</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><span class="hlt">Substorm</span> Evolution in the Near-Earth Plasma Sheet</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, <span class="hlt">phase</span>-out funding for the project of the same name (NAG5-9110 to Boston University) to determine precursors and signatures of local <span class="hlt">substorm</span> onset and how they evolve in the plasma sheet using the Geotail near-Earth database. We report here on two accomplishments: (1) Completion of an examination of plasma 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 plasma at times of <span class="hlt">substorm</span> injections.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19940033530&hterms=current+sheet&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dcurrent%2Bsheet','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19940033530&hterms=current+sheet&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dcurrent%2Bsheet"><span>On the cause of thin current sheets in the near-Earth magnetotail and their possible significance for magnetospheric <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schindler, K.; Birn, J.</p> <p>1993-01-01</p> <p>The formation of thin current sheets in the near-Earth magnetotail during <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phases</span> is addressed in terms of a simple model. An appropriate part of the unperturbed magnetotail is represented by a plane sheet model. Perturbations are applied to the upper and to the left boundaries, representing the magnetopause and the near-Earth tail boundary, where the perturbation at the latter models the interaction between the tail and the inner magnetosphere. Treating the perturbation as ideal (dissipation-free), we found that singular current sheets develop in the midplane of the tail. The analytical results are explored numerically. Using realistic dimensions of the domain considered, the influence of the earthward boundary on current sheet formation dominates. It is argued that current sheet formation of this type plays an important role in the processes associated with the onset of magnetospheric <span class="hlt">substorms</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.2808C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.2808C"><span>Solar cycle dependence of <span class="hlt">substorm</span> occurrence and duration: Implications for onset</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chu, Xiangning; McPherron, Robert L.; Hsu, Tung-Shin; Angelopoulos, Vassilis</p> <p>2015-04-01</p> <p>Magnetospheric <span class="hlt">substorms</span> represent a major energy release process in Earth's magnetosphere. Their duration and intensity are coupled to solar wind input, but the precise way the solar wind energy is stored and then released is a matter of considerable debate. Part of the observational difficulty has been the gaps in the auroral electrojet index traditionally used to study <span class="hlt">substorm</span> properties. In this study, we created a midlatitude positive bay (MPB) index to measure the strength of the <span class="hlt">substorm</span> current wedge. Because this index is based on midlatitude magnetometer data that are available continuously over several decades, we can assemble a database of <span class="hlt">substorm</span> onsets lasting 31 years (1982-2012). We confirmed that the MPB onsets have a good agreement (±2 min) with auroral onsets as determined by optical means on board the IMAGE mission and that the MPB signature of <span class="hlt">substorms</span> is robust and independent of the stations' position relative to ionospheric currents. Using the MPB onset, expansion, and recovery as a proxy of the respective <span class="hlt">substorm</span> quantities, we found that the solar cycle variation of <span class="hlt">substorm</span> occurrence depends on solar wind conditions and has a most probable value of 80 min. In contrast, the durations of <span class="hlt">substorm</span> expansion and recovery <span class="hlt">phases</span> do not change with the solar cycle. This suggests that the frequency of energy unloading in the magnetosphere is controlled by solar wind conditions through dayside reconnection, but the unloading process related to flux pileup in the near-Earth region is controlled by the magnetosphere and independent of external driving.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6154568','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6154568"><span><span class="hlt">Substorms</span> - Future of magnetospheric <span class="hlt">substorm</span>-storm research</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Akasofu, S.I. )</p> <p>1989-04-01</p> <p>Seven approaches and/or areas of magnetospheric <span class="hlt">substorm</span> and storm science which should be emphasized in future research are briefly discussed. They are: the combining of groups of researchers who study magnetic storms and <span class="hlt">substorms</span> in terms of magnetic reconnection with those that do not, the possible use of a magnetosphere-ionosphere coupling model to merge the groups, the development of improved input-output relationships, the complementing of satellite and ground-based observations, the need for global imaging of the magnetosphere, the complementing of observations with computer simulations, and the need to study the causes of changes in the north-south component of the IMF. 36 refs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002JGRA..107.1259M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002JGRA..107.1259M"><span>A comparison of <span class="hlt">substorms</span> occurring during magnetic storms with those occurring during quiet times</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McPherron, R. L.; Hsu, T.-S.</p> <p>2002-09-01</p> <p>It has been suggested that there may be a fundamental difference between <span class="hlt">substorms</span> that occur during magnetic storms and those that occur at other times. [1996] presented evidence that there is no obvious change in lobe field in "quiet time" <span class="hlt">substorms</span> but that "storm time" <span class="hlt">substorms</span> exhibit the classic pattern of storage and release of lobe field energy. This result led them to speculate that the former are caused by current sheet disruption, while the latter are caused by reconnection of lobe flux. In this paper we examine their hypothesis with a much larger data set using definitions of the two types of <span class="hlt">substorms</span> similar to theirs, as well as additional more restrictive definitions of these classes of events. Our results show that the only differences between the various classes are the absolute value of the lobe field and the size of the changes. When the data are normalized to unit field amplitude, we find that the percent change during storm time and non-storm time <span class="hlt">substorms</span> is nearly the same. The above conclusions are demonstrated with superposed epoch analysis of lobe field (Bt and Bz) for four classes of <span class="hlt">substorms</span>: active times (Dst < -50 nT, mostly recovery <span class="hlt">phase</span>), main <span class="hlt">phase</span> <span class="hlt">substorms</span>, non-storm times (Dst > -25 nT), and quiet time <span class="hlt">substorms</span> (no evidence of storm in Dst). Epoch zero for the analysis was taken as the main <span class="hlt">substorm</span> onset (Pi2 onset closest to sharp break in AL index). Our results suggest that there is no qualitative distinction between the various classes of <span class="hlt">substorms</span>, and so they are all likely to be caused by the same mechanism.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.1697H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.1697H"><span><span class="hlt">Substorm</span> onset: Current sheet avalanche and stop layer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Haerendel, Gerhard</p> <p>2015-03-01</p> <p>A new scenario is presented for the onset of a <span class="hlt">substorm</span> and the nature of the breakup arc. There are two main components, current sheet avalanche and stop layer. The first refers to an earthward flow of plasma and magnetic flux from the central current sheet of the tail, triggered spontaneously or by some unknown interaction with an auroral streamer or a suddenly appearing eastward flow at the end of the <span class="hlt">growth</span> <span class="hlt">phase</span>. The second offers a mechanism to stop the flow abruptly at the interface between magnetosphere and tail and extract momentum and energy to be partially processed locally and partially transmitted as Poynting flux toward the ionosphere. The stop layer has a width of the order of the ion inertial length. The different dynamics of the ions entering freely and the magnetized electrons create an electric polarization field which stops the ion flow and drives a Hall current by which flow momentum is transferred to the magnetic field. A simple formalism is used to describe the operation of the process and to enable quantitative conclusions. An important conclusion is that by necessity the stop layer is also highly structured in longitude. This offers a natural explanation for the coarse ray structure of the breakup arc as manifestation of elementary paths of energy and momentum transport. The currents aligned with the rays are balanced between upward and downward directions. While the avalanche is invoked for explaining the spontaneous <span class="hlt">substorm</span> onset at the inner edge of the tail, the expansion of the breakup arc for many minutes is taken as evidence for a continued formation of new stop layers by arrival of flow bursts from the near-Earth neutral line. This is in line with earlier conclusions about the nature of the breakup arc. Small-scale structure, propagation speed, and energy flux are quantitatively consistent with observations. However, the balanced small-scale currents cannot constitute the <span class="hlt">substorm</span> current wedge. The source of the latter must be</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.P41F..02I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.P41F..02I"><span>The <span class="hlt">Substorm</span> Cycle at Mercury</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Imber, S. M.; Slavin, J. A.</p> <p>2015-12-01</p> <p>The large-scale dynamic behavior of Mercury's highly compressed magnetosphere is primarily powered by magnetic reconnection between the solar wind and the planetary magnetic field. Reconnection transfers energy and momentum from the solar wind to the magnetosphere and drives the large-scale circulation of magnetic flux through the system, predominantly via the <span class="hlt">substorm</span> cycle. We will present a statistical analysis of the average <span class="hlt">substorm</span> amplitude, duration and frequency using magnetic field data acquired in orbit about Mercury by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. We will also present an example of steady magnetospheric convection in Mercury's magnetosphere, during which reconnection is ongoing both at the dayside magnetopause and in the magnetotail, but large-scale magnetic energy storage and release is not observed. We aim to ascertain the combination of internal magnetospheric and external solar wind parameters that lead to a <span class="hlt">substorm</span>, or a period of steady magnetospheric convection in Mercury's magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940023715','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940023715"><span>Proton aurora and <span class="hlt">substorm</span> intensifications</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Samson, J. C.; Xu, B.; Lyons, L. R.; Newell, P. T.; Creutzberg, F.</p> <p>1993-01-01</p> <p>Ground based measurements from the CANOPUS array of meridian scanning photometers and precipitating ion and electron data from the DMSP F9 satellite show that the electron arc which brightens to initiate <span class="hlt">substorm</span> intensifications is formed within a region of intense proton precipitation that is well equatorward (approximately four to six degrees) of the nightside open-closed field line boundary. The precipitating protons are from a population that is energized via earthward convection from the magnetotail into the dipolar region of the magnetosphere and may play an important role in the formation of the electron arcs leading to <span class="hlt">substorm</span> intensifications on dipole-like field lines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008cosp...37.3660Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008cosp...37.3660Z"><span>Multipoint measurements of <span class="hlt">substorm</span> timing and activations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zuyin, Pu; Cao, X.; Zhang, H.; Ma, Z. W.; Mishin, M. V.; Kubyshkina, M. V.; Pulkkinen, T.; Reeves, G. D.; Escoubet, C. Philippe</p> <p></p> <p><span class="hlt">Substorm</span> timing and activations are studied based on Double Star TC1, Cluster, Polar, IM- AGE, LANL satellites and ground-based Pi2 measurements. <span class="hlt">Substorm</span> expansion onset is found to begin in the near-Earth tail around X= -(8-9) Re, then progresses both earthward and tailward. About 8-10 minutes before aurora breakup, Cluster measured an earthward flow associated with plasma sheet thinning. A couple of minutes after the breakup, TC1 first detects plasma sheet expansion and then LANL satellites near the midnight measure energetic electron injections, or vise versus. About 20 minutes (or more) later, Cluster and Polar observe plasma sheet expansion successively. Of interest are also the following findings. Auroral bulge is found to quickly broaden and expand poleward when the open magnetic flux of the polar cap is rapidly dissipated, indicating the role of tail lobe reconnection of open field lines in the development of the expansion <span class="hlt">phase</span>. In addition, poleward expansion of auroral bulges and tailward progression of <span class="hlt">substorm</span> expansion are shown to be closely related. An initial dipolarization in the near-Earth eventually evolve to enable disruption of the cross-tail current in a wide range of the magnetotail, until the open magnetic flux of the polar cap reaches its minimum. Acknowledgements This work is supported by the NSFC Grants 40390152 and 40536030 and Chinese Key Research Project Grant 2006CB806300. The authors acknowledge all PIs of instruments onboard Double Star and Cluster spacecraft. We also appreciate the useful discussions with R. L. McPherron and A. T. Y. Lui.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007Ge%26Ae..47..193V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007Ge%26Ae..47..193V"><span>Features of the planetary distribution of auroral precipitation characteristics during <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vorobjev, V. G.; Yagodkina, O. I.; Starkov, G. V.; Feldstein, Ya. I.</p> <p>2007-04-01</p> <p>A planetary pattern of <span class="hlt">substorm</span> development in auroral precipitation has been constructed on the basis of the F6 and F7 satellite observations. The behavior of the auroral injection boundaries and characteristics of precipitating electrons in various precipitation regions during all <span class="hlt">phases</span> of a statistically mean magnetospheric <span class="hlt">substorm</span> with an intensity of AL ˜ -400 nT at a maximum is considered in detail. It is shown that during a <span class="hlt">substorm</span>, the zone of structured auroral oval precipitation AOP and the diffuse auroral zone DAZ are the widest in the nighttime and daytime sectors, respectively. In the daytime sector, all precipitation regions synchronously shift equatorward not only at the origination <span class="hlt">phase</span> but during the <span class="hlt">substorm</span> development <span class="hlt">phase</span>. The strongest shift to low latitudes of the daytime AOP region is observed at a maximum of the development <span class="hlt">phase</span>. As a result of this shift, the area of the polar cap increases during the <span class="hlt">phases</span> of <span class="hlt">substorm</span> origination and development. It is shown that the average position of the precipitation boundaries and the energy fluxes of precipitating electrons at each <span class="hlt">phase</span> are linearly related to the intensity of a magnetic disturbance. This makes it possible to develop a model of auroral precipitation development during each <span class="hlt">phase</span> of <span class="hlt">substorms</span> of any intensity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870048934&hterms=ISEE-3&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DISEE-3','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870048934&hterms=ISEE-3&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DISEE-3"><span>Simultaneous observations of the near-earth and distant geomagnetic tail during a <span class="hlt">substorm</span> by ISEE-1, ISEE-3 and geostationary spacecraft</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Richardson, I. G.; Scholer, M.; Tsurutani, B. T.; Daly, P. W.; Baker, D. N.</p> <p>1987-01-01</p> <p>The structure of the geomagnetic tail during a <span class="hlt">substorm</span> is investigated by combining plasma, magnetic field, and energetic particle data from the ISEE-3 spacecraft in the deep tail with similar near-earth observations from ISEE-1 and geostationary spacecraft. The observations can be interpreted in terms of the neutral-line model of <span class="hlt">substorms</span> and indicate the formation of a closed-loop field region (plasmoid) following <span class="hlt">substorm</span> onset, which is ejected down the tail. The plasmoid is observed to have a double-loop field strucure. This may be the result of a second <span class="hlt">substorm</span> onset occurring about 25 min after the first, producing a further near-earth neutral line and closed field loop. During the <span class="hlt">substorm</span> recovery <span class="hlt">phase</span>, the <span class="hlt">substorm</span> neutral line moves tailward to beyond 130 earth radii from earth by some 3 h after <span class="hlt">substorm</span> onset.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM44A..09M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM44A..09M"><span>In-situ measurement of the <span class="hlt">substorm</span> onset instability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Murphy, K. R.; Rae, J.; Watt, C.; Forsyth, C.; Mann, I. R.; Yao, Z.; Kalmoni, N.</p> <p>2015-12-01</p> <p>The <span class="hlt">substorm</span> is arguably the major mode of variability in near-Earth Space which unpredictably dissipates a considerable and variable amount of energy into the near-Earth magnetosphere and ionosphere. What process or processes determine when this energy is released is uncertain, although it is evident that both near-Earth plasma instability and magnetotail reconnection play a role in this energy release. Much emphasis has recently been placed on the role of magnetic reconnection in <span class="hlt">substorms</span>, we focus here on observations of the unmistakeable signs of a plasma instability acting at <span class="hlt">substorm</span> onset. Using data from the THEMIS spacecraft, we show that electromagnetic waves grow in the magnetotail at the expense of the local electron and ion thermal energy. The wave <span class="hlt">growth</span> in space is the direct counterpart to the wave <span class="hlt">growth</span> seen at the <span class="hlt">substorm</span> onset location at the ionosphere, as measured by the CARISMA and THEMIS magnetometers and THEMIS all-sky-imagers. We present evidence that the free energy source for the instability is associated with the electron and ion thermal energy, and not the local electron or ion flow energy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19980210628&hterms=phd&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dphd','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19980210628&hterms=phd&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dphd"><span>Magnetospheric <span class="hlt">Substorms</span> and Tail Dynamics</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hughes, W. Jeffrey</p> <p>1998-01-01</p> <p>This grant funded several studies of magnetospheric <span class="hlt">substorms</span> and their effect on the dynamics of the earth's geomagnetic tail. We completed an extensive study of plasmoids, plasma/magnetic field structures that travel rapidly down the tail, using data from the ISEE 3 and IMP 8 spacecraft. This study formed the PhD thesis of Mark Moldwin. We found that magnetically plasmoids are better described as flux-ropes (twisted magnetic flux tubes) rather than plasma bubbles, as had been generally regarded up to that point (Moldwin and Hughes, 1990; 1991). We published several examples of plasmoids observed first in the near tail by IMP 8 and later in the distant tail by ISEE 3, confirming their velocities down tail. We showed how the passage of plasmoids distorts the plasma sheet. We completed the first extensive statistical survey of plasmoids that showed how plasmoids evolve as they move down tail from their formation around 30 RE to ISEE 3 apogee at 240 RE. We established a one-to-one correspondence between the observation of plasmoids in the distant tail and <span class="hlt">substorm</span> onsets at earth or in the near tail. And we showed that there is a class of plasmoid-like structures that move slowly earthward, especially following weak <span class="hlt">substorms</span> during northward IMF. Collectively this work constituted the most extensive study of plasmoids prior to the work that has now been done with the GEOTAIL spacecraft. Following our work on plasmoids, we turned our attention to signatures of <span class="hlt">substorm</span> onset observed in the inner magnetosphere near geosynchronous orbit, especially signatures observed by the CRRES satellite. Using data from the magnetometer, electric field probe, plasma wave instrument, and low energy plasma instrument on CRRES we were able to better document <span class="hlt">substorm</span> onsets in the inner magnetosphere than had been possible previously. Detailed calculation of the Poynting flux showed energy exchange between the magnetosphere and ionosphere, and a short burst of tailward convective</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SpWea..15..131G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SpWea..15..131G"><span>The <span class="hlt">substorm</span> cycle as reproduced by global MHD models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gordeev, E.; Sergeev, V.; Tsyganenko, N.; Kuznetsova, M.; Rastäetter, L.; Raeder, J.; Tóth, G.; Lyon, J.; Merkin, V.; Wiltberger, M.</p> <p>2017-01-01</p> <p>Recently, Gordeev et al. (2015) suggested a method to test global MHD models against statistical empirical data. They showed that four community-available global MHD models supported by the Community Coordinated Modeling Center (CCMC) produce a reasonable agreement with reality for those key parameters (the magnetospheric size, magnetic field, and pressure) that are directly related to the large-scale equilibria in the outer magnetosphere. Based on the same set of simulation runs, here we investigate how the models reproduce the global loading-unloading cycle. We found that in terms of global magnetic flux transport, three examined CCMC models display systematically different response to idealized 2 h north then 2 h south interplanetary magnetic field (IMF) Bz variation. The LFM model shows a depressed return convection and high loading rate during the <span class="hlt">growth</span> <span class="hlt">phase</span> as well as enhanced return convection and high unloading rate during the expansion <span class="hlt">phase</span>, with the amount of loaded/unloaded magnetotail flux and the <span class="hlt">growth</span> <span class="hlt">phase</span> duration being the closest to their observed empirical values during isolated <span class="hlt">substorms</span>. Two other models exhibit drastically different behavior. In the BATS-R-US model the plasma sheet convection shows a smooth transition to the steady convection regime after the IMF southward turning. In the Open GGCM a weak plasma sheet convection has comparable intensities during both the <span class="hlt">growth</span> <span class="hlt">phase</span> and the following slow unloading <span class="hlt">phase</span>. We also demonstrate potential technical problem in the publicly available simulations which is related to postprocessing interpolation and could affect the accuracy of magnetic field tracing and of other related procedures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20170008032&hterms=bat&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dbat','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20170008032&hterms=bat&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dbat"><span>The <span class="hlt">Substorm</span> Cycle as Reproduced by Global MHD Models</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gordeev, E.; Sergee, V.; Tsyganenko, N.; Kuznetsova, M.; Rastaetter, Lutz; Raeder, J.; Toth, G.; Lyon, J.; Merkin, V.; Wiltberger, M.</p> <p>2017-01-01</p> <p>Recently, Gordeev et al. (2015) suggested a method to test global MHD models against statistical empirical data. They showed that four community-available global MHD models supported by the Community Coordinated Modeling Center (CCMC) produce a reasonable agreement with reality for those key parameters (the magnetospheric size, magnetic field, and pressure) that are directly related to the large-scale equilibria in the outer magnetosphere. Based on the same set of simulation runs, here we investigate how the models reproduce the global loading-unloading cycle. We found that in terms of global magnetic flux transport, three examined CCMC models display systematically different response to idealized2 h north then 2 h south interplanetary magnetic field (IMF) Bz variation. The LFM model shows a depressed return convection and high loading rate during the <span class="hlt">growth</span> <span class="hlt">phase</span> as well as enhanced return convection and high unloading rate during the expansion <span class="hlt">phase</span>, with the amount of loaded unloaded magnetotail flux and the <span class="hlt">growth</span> <span class="hlt">phase</span> duration being the closest to their observed empirical values during isolated <span class="hlt">substorms</span>. Two other models exhibit drastically different behavior. In the BATS-R-US model the plasma sheet convection shows a smooth transition to the steady convection regime after the IMF southward turning. In the Open GGCM a weak plasma sheet convection has comparable intensities during both the <span class="hlt">growth</span> <span class="hlt">phase</span> and the following slow unloading <span class="hlt">phase</span>. We also demonstrate potential technical problem in the publicly available simulations which is related to post processing interpolation and could affect the accuracy of magnetic field tracing and of other related procedures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AnGeo..24.1905A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AnGeo..24.1905A"><span>Method to locate the polar cap boundary in the nightside ionosphere and application to a <span class="hlt">substorm</span> event</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aikio, A. T.; Pitkänen, T.; Kozlovsky, A.; Amm, O.</p> <p>2006-08-01</p> <p>In this paper we describe a new method to be used for the polar cap boundary (PCB) determination in the nightside ionosphere by using the EISCAT Svalbard radar (ESR) field-aligned measurements by the 42-m antenna and southward directed low-elevation measurements by the ESR 32 m antenna or northward directed low-elevation measurements by the EISCAT VHF radar at Tromsø. The method is based on increased electron temperature (Te) caused by precipitating particles on closed field lines. Since the Svalbard field-aligned measurement provides the reference polar cap Te height profile, the method can be utilised only when the PCB is located between Svalbard and the mainland. Comparison with the Polar UVI images shows that the radar-based method is generally in agreement with the PAE (poleward auroral emission) boundary from Polar UVI. <P style="line-height: 20px;"> The new technique to map the polar cap boundary was applied to a <span class="hlt">substorm</span> event on 6 November 2002. Simultaneous measurements by the MIRACLE magnetometers enabled us to put the PCB location in the framework of ionospheric electrojets. During the <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phase</span>, the polar cap expands and the region of the westward electrojet shifts gradually more apart from the PCB. The <span class="hlt">substorm</span> onset takes place deep within the region of closed magnetic field region, separated by about 6-7° in latitude from the PCB in the ionosphere. We interpret the observations in the framework of the near-Earth neutral line (NENL) model of <span class="hlt">substorms</span>. After the <span class="hlt">substorm</span> onset, the reconnection at the NENL reaches within 3 min the open-closed field line boundary and then the PCB moves poleward together with the poleward boundary of the <span class="hlt">substorm</span> current wedge. The poleward expansion occurs in the form of individual bursts, which are separated by 2-10 min, indicating that the reconnection in the magnetotail neutral line is impulsive. The poleward expansions of the PCB are followed by latitude dispersed intensifications in the westward</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..12111826T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..12111826T"><span>Prompt enhancement of the Earth's outer radiation belt due to <span class="hlt">substorm</span> electron injections</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.; Zhang, J.-C.; Reeves, G. D.; Su, Z. P.; Baker, D. N.; Spence, H. E.; Funsten, H. O.; Blake, J. B.; Wygant, J. R.</p> <p>2016-12-01</p> <p>We present multipoint simultaneous observations of the near-Earth magnetotail and outer radiation belt during the <span class="hlt">substorm</span> electron injection event on 16 August 2013. Time History of Events and Macroscale Interactions during <span class="hlt">Substorms</span> A in the near-Earth magnetotail observed flux-enhanced electrons of 300 keV during the magnetic field dipolarization. Geosynchronous orbit satellites also observed the intensive electron injections. Located in the outer radiation belt, RBSP-A observed enhancements of MeV electrons accompanied by <span class="hlt">substorm</span> dipolarization. The <span class="hlt">phase</span> space density (PSD) of MeV electrons at L* 5.4 increased by 1 order of magnitude in 1 h, resulting in a local PSD peak of MeV electrons, which was caused by the direct effect of <span class="hlt">substorm</span> injections. Enhanced MeV electrons in the heart of the outer radiation belt were also detected within 2 h, which may be associated with intensive <span class="hlt">substorm</span> electron injections and subsequent local acceleration by chorus waves. Multipoint observations have shown that <span class="hlt">substorm</span> electron injections not only can be the external source of MeV electrons at the outer edge of the outer radiation belt (L* 5.4) but also can provide the intensive seed populations in the outer radiation belt. These initial higher-energy electrons from injection can reach relativistic energy much faster. The observations also provide evidence that enhanced <span class="hlt">substorm</span> electron injections can explain rapid enhancements of MeV electrons in the outer radiation belt.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JGRA..118.2958C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JGRA..118.2958C"><span>On the influence of open magnetic flux on <span class="hlt">substorm</span> intensity: Ground- and space-based observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Clausen, L. B. N.; Milan, S. E.; Baker, J. B. H.; Ruohoniemi, J. M.; Glassmeier, K.-H.; Coxon, J. C.; Anderson, B. J.</p> <p>2013-06-01</p> <p>Using the location of maximum region 1 current determined by the Active Magnetosphere and Planetary Electrodynamics Response Experiment as a proxy for the open/closed field line boundary, we monitor the evolution of the amount of open magnetic flux inside the magnetosphere during 772 <span class="hlt">substorms</span>. We then divide all <span class="hlt">substorms</span> into three classes, depending on the amount of open flux at expansion <span class="hlt">phase</span> onset. Studying the temporal variations during the <span class="hlt">substorms</span> of each class for a number of related geophysical parameters, we find that <span class="hlt">substorms</span> occurring while the amount of open flux is large are generally more intense. By intense we mean that the auroral electrojet, region 1 current, auroral brightness, tail dipolarization and flow speed, ground magnetic signatures, Pi2 wave power, as well as the intensity and extent of the <span class="hlt">substorm</span> current wedge (SCW) are all larger than during <span class="hlt">substorms</span> that occur on a contracted polar cap. The SCW manifests itself as an intensification of the nightside R1 and R2 current system after onset. Our analysis shows that to dispose of large amounts of accumulated open magnetic flux, large <span class="hlt">substorms</span> are triggered in the terrestrial magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AdSpR..41.1585T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AdSpR..41.1585T"><span>Plasma sheet oscillations and their relation to <span class="hlt">substorm</span> development: Cluster and double star TC1 case study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Takada, T.; Nakamura, R.; Asano, Y.; Baumjohann, W.; Runov, A.; Volwerk, M.; Zhang, T. L.; Vörös, Z.; Keika, K.; Klecker, B.; Rème, H.; Lucek, E. A.; Carr, C.; Frey, H. U.</p> <p></p> <p>We examined two consecutive plasma sheet oscillation and dipolarization events observed by Cluster in the magnetotail, which are associated with a pseudo-breakup and a small <span class="hlt">substorm</span> monitored by the IMAGE spacecraft. Energy input from the solar wind and an associated enhancement of the cross-tail current lead to current sheet thinning and plasma sheet oscillations of 3 5 min periods, while the pseudo-breakups occur during the loading <span class="hlt">phase</span> within a spatially limited area, accompanied by a localized dipolarization observed by DSP TC1 or GOES 12. That is, the so-called “<span class="hlt">growth</span> phase” is a preferable condition for both pseudo-breakup and plasma sheet oscillations in the near-Earth magnetotail. One of the plasma sheet oscillation events occurs before the pseudo-breakup, whereas the other takes place after pseudo-breakup. Thus there is no causal relationship between the plasma sheet oscillation events and pseudo-breakup. As for the contribution to the subsequent small <span class="hlt">substorm</span>, the onset of the small <span class="hlt">substorm</span> took place where the preceding plasma sheet oscillations can reach the region.</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('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4024764','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4024764"><span>Rapid control of <span class="hlt">phase</span> <span class="hlt">growth</span> by nanoparticles</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Chen, Lian-Yi; Xu, Jia-Quan; Choi, Hongseok; Konishi, Hiromi; Jin, Song; Li, Xiao-Chun</p> <p>2014-01-01</p> <p>Effective control of <span class="hlt">phase</span> <span class="hlt">growth</span> under harsh conditions (such as high temperature, highly conductive liquids or high <span class="hlt">growth</span> rate), where surfactants are unstable or ineffective, is still a long-standing challenge. Here we show a general approach for rapid control of diffusional <span class="hlt">growth</span> through nanoparticle self-assembly on the fast-growing <span class="hlt">phase</span> during cooling. After <span class="hlt">phase</span> nucleation, the nanoparticles spontaneously assemble, within a few milliseconds, as a thin coating on the growing <span class="hlt">phase</span> to block/limit diffusion, resulting in a uniformly dispersed <span class="hlt">phase</span> orders of magnitude smaller than samples without nanoparticles. The effectiveness of this approach is demonstrated in both inorganic (immiscible alloy and eutectic alloy) and organic materials. Our approach overcomes the microstructure refinement limit set by the fast <span class="hlt">phase</span> <span class="hlt">growth</span> during cooling and breaks the inherent limitations of surfactants for <span class="hlt">growth</span> control. Considering the growing availability of numerous types and sizes of nanoparticles, the nanoparticle-enabled <span class="hlt">growth</span> control will find broad applications. PMID:24809454</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997APS..DPPeMI201B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997APS..DPPeMI201B"><span>Dynamics of Thin Current Sheets and Their Disruption by Ballooning Instabilities: a Mechanism for Magnetospheric <span class="hlt">Substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bhattacharjee, A.</p> <p>1997-11-01</p> <p>During the <span class="hlt">growth</span> <span class="hlt">phase</span>, the magnetotail is prepared for the violent relaxation dynamics that occurs at <span class="hlt">substorm</span> onset. Multi-satellite observations indicate the development of a thin current sheet and a rapid intensification of the cross-tail current density at near-Earth distances during a short interval (< 1 min) just before onset, after a period of sluggish <span class="hlt">growth</span> ( ~ 0.5-1.5 hr). These observational features have been accounted for recently by analysis as well as high-resolution MHD simulation of the magnetotail, including the Earth's dipole field. In the slow <span class="hlt">growth</span> and impulsive pre-onset <span class="hlt">phase</span>, it is shown that a thin current sheet develops spanning Y-points that stretch from the mid-tail region ( ~ 30 R_E) to the near-Earth region ( ~ 10 R_E). The current sheet dynamics exhibits an impulsive enhancement in amplitude and the flows are dominantly earthward, consistent with observations. When the current sheet becomes sufficiently thin, finite ion-Larmor-radius terms such as electron pressure gradients and Hall currents must be included in the theory and are shown to have a striking effect on the dynamics in the impulsive <span class="hlt">growth</span> <span class="hlt">phase</span>. It is shown that the thin current sheet is unstable to ideal ballooning instabilities with rapid spatial variation in the dawn-dusk direction. Ionospheric boundary conditions can have a strong influence on the linear properties of the ballooning instability, especially at near-Earth distances. Once the linear mode is triggered, nonlinear studies indicate a tendency for near-explosive <span class="hlt">growth</span> of the instability, suggesting its possible role as a mechanism for <span class="hlt">substorm</span> onset.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.4015K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.4015K"><span>Some features of the Pi2 bursts during triggered and nontriggered <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Klain, B. I.; Kurazhkovskaya, N. A.</p> <p>2009-04-01</p> <p>The character of amplitudes and duration distributions of the Pi2 bursts observed in nighttime was investigated during development magnetospheric <span class="hlt">substorms</span>. The analog recordings of the middle latitude Borok observatory (corrected geomagnetic latitude and longitude: 53.6; 114.4) for 1994-1995 were used in the investigation. We separate the Pi2 bursts into two classes: 1) Pi2 observed during <span class="hlt">substorms</span> which were triggered by the external factors and 2) Pi2 observed during <span class="hlt">substorms</span> which were occurred spontaneously. Both northward and southward turnings IMF Bz were considered as the possible triggers of the magnetospheric <span class="hlt">substorms</span>. It was found that the distributions of Pi2 bursts amplitudes of both classes are submitted to the power law. The Pi2 bursts observed during triggered <span class="hlt">substorms</span> are the power-low index of the amplitudes distribution equal 2.64. To the power dependence with an index 2.50 are submitted Pi2 bursts observed during nontriggered <span class="hlt">substorms</span>. The results obtained make it possible to assume that the sequences of wave packets of Pi2 pulsations are intermittent process. The analysis of distributions of the Pi2 bursts duration two classes was shown that it are approximated by exponential functions with different indices. If the expansion <span class="hlt">phase</span> of <span class="hlt">substorms</span> is connected with IMF orientation change the index of approximated function made 0.43. In case of nontriggered <span class="hlt">substorms</span> the index of approximated function equal 0.36. It is supposed that on the basis of the obtained indices it is possible on a qualitative level to estimate a turbulence degree of plasma on the night side magnetosphere during development of <span class="hlt">substorm</span> activity. The work was supported by the Program of Basic Researches of Presidium of Russian Academy of Science "Change of a surroundings and climate: Extreme Natural Phenomena and Catastrophes"</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810046746&hterms=1041&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2526%25231041','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810046746&hterms=1041&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2526%25231041"><span>Computer simulation of a geomagnetic <span class="hlt">substorm</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lyon, J. G.; Brecht, S. H.; Huba, J. D.; Fedder, J. A.; Palmadesso, P. J.</p> <p>1981-01-01</p> <p>A global two-dimensional simulation of a substormlike process occurring in earth's magnetosphere is presented. The results are consistent with an empirical <span class="hlt">substorm</span> model - the neutral-line model. Specifically, the introduction of a southward interplanetary magnetic field forms an open magnetosphere. Subsequently, a <span class="hlt">substorm</span> neutral line forms at about 15 earth radii or closer in the magnetotail, and plasma sheet thinning and plasma acceleration occur. Eventually the <span class="hlt">substorm</span> neutral line moves tailward toward its presubstorm position.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810046746&hterms=1041&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3D%2526%25231041','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810046746&hterms=1041&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3D%2526%25231041"><span>Computer simulation of a geomagnetic <span class="hlt">substorm</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lyon, J. G.; Brecht, S. H.; Huba, J. D.; Fedder, J. A.; Palmadesso, P. J.</p> <p>1981-01-01</p> <p>A global two-dimensional simulation of a substormlike process occurring in earth's magnetosphere is presented. The results are consistent with an empirical <span class="hlt">substorm</span> model - the neutral-line model. Specifically, the introduction of a southward interplanetary magnetic field forms an open magnetosphere. Subsequently, a <span class="hlt">substorm</span> neutral line forms at about 15 earth radii or closer in the magnetotail, and plasma sheet thinning and plasma acceleration occur. Eventually the <span class="hlt">substorm</span> neutral line moves tailward toward its presubstorm position.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JGRA..118..774P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JGRA..118..774P"><span>Observations of polar cap flow channel and plasma sheet flow bursts during <span class="hlt">substorm</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>PitkäNen, T.; Aikio, A. T.; Juusola, L.</p> <p>2013-02-01</p> <p>We present the first simultaneous observations of an enhanced polar cap flow impinging on the nightside polar cap boundary (PCB), two flow bursts in the plasma sheet and a conjugate ionospheric flow burst within the auroral oval. The ionospheric measurements on 3 September 2006 were made by the European Incoherent Scatter (EISCAT) radars and the magnetospheric measurements by the four Cluster spacecraft. In the end of a <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phase</span>, EISCAT measured a channel of enhanced equatorward plasma flow within the polar cap, which was about 1° wide in latitude and drifted slowly equatorward. During the <span class="hlt">substorm</span> expansion <span class="hlt">phase</span>, the PCB started to contract poleward. The interaction between the equatorward drifting polar cap flow channel and the poleward contracting PCB took 2-3 min. During this time, the F-region electron temperature was elevated at the PCB, which is interpreted as a possible signature of an auroral poleward boundary intensification (PBI). After that, enhanced equatorward flows were measured inside the auroral oval by EISCAT. During this period, the Cluster satellites measured two fast earthward flow bursts in the plasma sheet, which were associated with dipolarizations of the magnetic field, depletions in plasma density, and return flows. We suggest that the second flow burst in the plasma sheet represents the same flow burst that is seen in the ionosphere by EISCAT and propose that the plasma sheet flow bursts were triggered by the enhanced flow structure on open polar cap field lines. The suggestion is in line with Lyons et al. (2011).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..122.3055K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..122.3055K"><span>Comparing and contrasting dispersionless injections at geosynchronous orbit during a <span class="hlt">substorm</span> event</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kronberg, E. A.; Grigorenko, E. E.; Turner, D. L.; Daly, P. W.; Khotyaintsev, Y.; Kozak, L.</p> <p>2017-03-01</p> <p>Particle injections in the magnetosphere transport electrons and ions from the magnetotail to the radiation belts. Here we consider generation mechanisms of "dispersionless" injections, namely, those with simultaneous increase of the particle flux over a wide energy range. In this study we take advantage of multisatellite observations which simultaneously monitor Earth's magnetospheric dynamics from the tail toward the radiation belts during a <span class="hlt">substorm</span> event. Dispersionless injections are associated with instabilities in the plasma sheet during the <span class="hlt">growth</span> <span class="hlt">phase</span> of the <span class="hlt">substorm</span>, with a dipolarization front at the onset and with magnetic flux pileup during the expansion <span class="hlt">phase</span>. They show different spatial spread and propagation characteristics. Injection associated with the dipolarization front is the most penetrating. At geosynchronous orbit (6.6 RE), the electron distributions do not have a classic power law fit but instead a bump on tail centered on ˜120 keV during dispersionless electron injections. However, electron distributions of injections associated with magnetic flux pileup in the magnetotail (13 RE) do not show such a signature. We surmise that an additional resonant acceleration occurs in between these locations. We relate the acceleration mechanism to the electron drift resonance with ultralow frequency waves localized in the inner magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.7381K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.7381K"><span>Comparing and contrasting dispersionless injections at geosynchronous orbit during a <span class="hlt">substorm</span> event</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kronberg, Elena; Grigorenko, Elena; Turner, Drew; Daly, Patrick; Khotyaintsev, Yuri; Kozak, Liudmyla</p> <p>2017-04-01</p> <p>Particle injections in the magnetosphere transport electrons and ions from the magnetotail to the radiation belts. We consider generation mechanisms of ``dispersionless'' injections, namely those with simultaneous increase of the particle flux over a wide energy range. We take advantage of multi-satellite observations which simultaneously monitor Earth's magnetospheric dynamics from the tail towards the radiation belts during a <span class="hlt">substorm</span> event. Dispersionless injections are associated with instabilities in the plasma sheet during the <span class="hlt">growth</span> <span class="hlt">phase</span> of the <span class="hlt">substorm</span>, with a dipolarization front at the onset and with magnetic flux pileup during the expansion <span class="hlt">phase</span>. They show different spatial spread and propagation characteristics. At geosynchronous orbit (6.6 RE), the electron distributions do not have a classic power law fit but instead a bump-on-tail centered on 120 keV during dispersionless electron injections. However, electron distributions of injections associated with magnetic flux pileup in the magnetotail (13 RE) do not show such a signature. We surmise that an additional resonant acceleration occurs in-between these locations. We relate the acceleration mechanism to the electron drift resonance with ultralow frequency (ULF) waves localized in the inner magnetosphere. This study is supported by the Volkswagen Foundation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/298593','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/298593"><span>Current understanding of magnetic storms: Storm-<span class="hlt">substorm</span> relationships</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kamide, Y.; Gonzalez, W.D.; Baumjohann, W.; Daglis, I.A.; Grande, M.; Joselyn, J.A.; Singer, H.J.; McPherron, R.L.; Phillips, J.L.; Reeves, E.G.; Rostoker, G.; Sharma, A.S.; Tsurutani, B.T.</p> <p>1998-08-01</p> <p>This paper attempts to summarize the current understanding of the storm/<span class="hlt">substorm</span> relationship by clearing up a considerable amount of controversy and by addressing the question of how solar wind energy is deposited into and is dissipated in the constituent elements that are critical to magnetospheric and ionospheric processes during magnetic storms. (1) Four mechanisms are identified and discussed as the primary causes of enhanced electric fields in the interplanetary medium responsible for geomagnetic storms. It is pointed out that in reality, these four mechanisms, which are not mutually exclusive, but interdependent, interact differently from event to event. Interplanetary coronal mass ejections (ICMEs) and corotating interaction regions (CIRs) are found to be the primary phenomena responsible for the main <span class="hlt">phase</span> of geomagnetic storms. The other two mechanisms, i.e., HILDCAA (high-intensity, long-duration, continuous auroral electrojet activity) and the so-called Russell-McPherron effect, work to make the ICME and CIR phenomena more geoeffective. The solar cycle dependence of the various sources in creating magnetic storms has yet to be quantitatively understood. (2) A serious controversy exists as to whether the successive occurrence of intense <span class="hlt">substorms</span> plays a direct role in the energization of ring current particles or whether the enhanced electric field associated with southward IMF enhances the effect of <span class="hlt">substorm</span> expansions. While most of the {ital Dst} variance during magnetic storms can be solely reproduced by changes in the large-scale electric field in the solar wind and the residuals are uncorrelated with <span class="hlt">substorms</span>, recent satellite observations of the ring current constituents during the main <span class="hlt">phase</span> of magnetic storms show the importance of ionospheric ions. This implies that ionospheric ions, which are associated with the frequent occurrence of intense <span class="hlt">substorms</span>, are accelerated upward along magnetic field lines, contributing to the energy density of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E.755G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E.755G"><span><span class="hlt">Substorms</span> observations over Apatity during geomagnetic storms in the period 2012 - 2016</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guineva, Veneta; Werner, Rolf; Despirak, Irina; Kozelov, Boris</p> <p>2016-07-01</p> <p>In this work we studied <span class="hlt">substorms</span>, generated during enhanced geomagnetic activity in the period 2012 - 2016. Observations of the Multiscale Aurora Imaging Network (MAIN) in Apatity have been used. Solar wind and interplanetary magnetic field parameters were judged by the 1-min sampled OMNI data base. <span class="hlt">Substorm</span> onset and further development were verified by the 10-s sampled data of IMAGE magnetometers and by data of the all-sky camera at Apatity. Subject of the study were <span class="hlt">substorms</span> occurred during geomagnetic storms. The so-called "St. Patrick's day 2015 event" (17-21 March 2015), the events on 17-18 March 2013 and 7-17 March 2012 (a chain of events generated four consecutive storms) which were among the events of strongest geomagnetic activity during the current solar cycle 24, were part of the storms under consideration. The behavior of the <span class="hlt">substorms</span> developed during different <span class="hlt">phases</span> of the geomagnetic storms was discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850041175&hterms=1054&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2526%25231054','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850041175&hterms=1054&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2526%25231054"><span>Dynamics of the 1054 UT March 22, 1979, <span class="hlt">substorm</span> event - CDAW 6. [Coordinated Data Analysis Workshop</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mcpherron, R. L.; Manka, R. H.</p> <p>1985-01-01</p> <p>The Coordinated Data Analysis Workshop (CDAW 6) has the primary objective to trace the flow of energy from the solar wind through the magnetosphere to its ultimate dissipation in the ionosphere. An essential role in this energy transfer is played by magnetospheric <span class="hlt">substorms</span>, however, details are not yet completely understood. The International Magnetospheric Study (IMS) has provided an ideal data base for the study conducted by CDAW 6. The present investigation is concerned with the 1054 UT March 22, 1979, <span class="hlt">substorm</span> event, which had been selected for detailed examination in connection with the studies performed by the CDAW 6. The observations of this <span class="hlt">substorm</span> are discussed, taking into account solar wind conditions, ground magnetic activity on March 22, 1979, observations at synchronous orbit, observations in the near geomagnetic tail, and the onset of the 1054 UT expansion <span class="hlt">phase</span>. <span class="hlt">Substorm</span> development and magnetospheric dynamics are discussed on the basis of a synthesis of the observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20060011203&hterms=shin&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dshin','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20060011203&hterms=shin&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dshin"><span>Average Characteristics of Triggered and Nontriggered <span class="hlt">Substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hsu, Tung-Shin; McPherron, Robert L.</p> <p>2004-01-01</p> <p>Magnetic field data from ground stations, geosynchronous orbit, and magnetotail are examined to study the response to <span class="hlt">substorm</span> activity with and without apparent interplanetary magnetic field (IMF) perturbations. Global <span class="hlt">substorms</span> are identified using a sudden, persistent decrease in the AL index. The onset of this global expansion is taken to be the time of the Pi2 burst nearest to the beginning of the AL decrease. IMF triggers were identified subjectively through visual scanning of the data. Both northward turnings of the IMF B, and decreases in the amplitude of the By component were considered as possible triggers. Two different solar wind monitors were used in the investigation: IMP 8 in a circular orbit with a distance between approx.12 and approx.35 R(sub E) from the Earth-Sun line and ISEE 2 in an elliptical orbit with a distance of only approx.5- 10 R(sub E) from the Earth-Sun line. The results of superposed epoch analysis show that the temporal response from ground stations, geosynchronous orbit, and magnetotail are nearly identical for triggered (with apparent IMF perturbation) and nontriggered (without apparent IMF perturbation) <span class="hlt">substorms</span>. It is therefore concluded that the nontriggered <span class="hlt">substorms</span> are not a different form of activity than triggered <span class="hlt">substorms</span>. However, we demonstrate that the magnitude of the response is different for the two types of substo&. By every measure considered, triggered <span class="hlt">substorm</span> are systematically larger than nontriggered <span class="hlt">substorms</span>. We interpret the fact that nearly 40% of all <span class="hlt">substorms</span> cannot be associated with an IMF trigger as evidence that <span class="hlt">substorms</span> are caused by an internal instability. However, the fact that so many appear to be triggered suggests that this internal instability is susceptible to external perturbations by the IMF. The fact that triggered <span class="hlt">substorms</span> are larger than nontriggered <span class="hlt">substorms</span> is counterintuitive, and we have no explanation for the observation.</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>Association of plasma sheet variations with auroral changes during <span class="hlt">substorms</span></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 <span class="hlt">substorm</span> are correlated with plasma measurements made concurrently by the ISEE 1 satellite in the magnetotail. Qualitative magnetic field configuration changes necessary to relate the plasma sheet boundary location to the latitude of the auroras are discussed. Evidence is presented that the longitudinal advances of the auroras after expansive <span class="hlt">phase</span> 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 <span class="hlt">phase</span> 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 <span class="hlt">substorm</span>'s recovery. 9 refs. 3 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950011869&hterms=Ramon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D40%26Ntt%3DRamon','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950011869&hterms=Ramon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D40%26Ntt%3DRamon"><span>On the relative importance of magnetospheric and ionospheric processes during <span class="hlt">substorm</span> onset and expansion: A case study</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lopez, Ramon E.</p> <p>1992-01-01</p> <p>The question of whether <span class="hlt">substorm</span> onset is triggered in the magnetotail or the ionosphere is presented. The possible influence of the ionosphere in the subsequent development of a <span class="hlt">substorm</span> is discussed. Theoretical considerations involved are reviewed and a case study to address this question is examined. The evidence indicates that magnetotail processes initiate the sequence of events called a <span class="hlt">substorm</span>, while the ionosphere appears to play a critical role in the subsequent evolution of the <span class="hlt">substorm</span> expansion <span class="hlt">phase</span>. However, the necessary observations, in particular high time resolution coordinated observations in the ionosphere and magnetotail are relatively rare. Continued examination of existing ground and space based data sets, in particular underutilized observations such as the Scatha data, may provide a more solid foundation for clarifying this issue and determining the relative importance of magnetospheric and ionospheric processes during <span class="hlt">substorms</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950011869&hterms=Ramon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DRamon%2BA.','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950011869&hterms=Ramon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DRamon%2BA."><span>On the relative importance of magnetospheric and ionospheric processes during <span class="hlt">substorm</span> onset and expansion: A case study</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lopez, Ramon E.</p> <p>1992-01-01</p> <p>The question of whether <span class="hlt">substorm</span> onset is triggered in the magnetotail or the ionosphere is presented. The possible influence of the ionosphere in the subsequent development of a <span class="hlt">substorm</span> is discussed. Theoretical considerations involved are reviewed and a case study to address this question is examined. The evidence indicates that magnetotail processes initiate the sequence of events called a <span class="hlt">substorm</span>, while the ionosphere appears to play a critical role in the subsequent evolution of the <span class="hlt">substorm</span> expansion <span class="hlt">phase</span>. However, the necessary observations, in particular high time resolution coordinated observations in the ionosphere and magnetotail are relatively rare. Continued examination of existing ground and space based data sets, in particular underutilized observations such as the Scatha data, may provide a more solid foundation for clarifying this issue and determining the relative importance of magnetospheric and ionospheric processes during <span class="hlt">substorms</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM23A2216H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM23A2216H"><span>Time development of high-altitude auroral acceleration region plasma, potentials, and field-aligned current systems observed by Cluster during a <span class="hlt">substorm</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hull, A. J.; Chaston, C. C.; Fillingim, M. O.; Mozer, F.; Frey, H. U.</p> <p>2013-12-01</p> <p>The auroral acceleration region is an integral link in the chain of events that transpire during <span class="hlt">substorms</span>, and the currents, plasma and electric fields undergo significant changes driven by complex dynamical processes deep in the magnetotail. These auroral acceleration processes in turn accelerate and heat the plasma that ultimately leads to some of the most intense global <span class="hlt">substorm</span> auroral displays. The complex interplay between field-aligned current system formation, the development of parallel electric fields, and resultant changes in the plasma constituents that occur during <span class="hlt">substorms</span> within or just above the auroral acceleration zone remain unclear. We present Cluster multi-point observations within the high-altitude acceleration region (> 3 Re altitude) at key instances during the development of a <span class="hlt">substorm</span>. Of particular emphasis is on the time-development of the plasma, potentials and currents that occur therein with the aim of ascertaining high-altitude drivers of <span class="hlt">substorm</span> active auroral acceleration processes and auroral emission consequences. Preliminary results show that the initial onset is dominated by Alfvenic activity as evidenced by the sudden occurrence of relatively intense, short-spatial scale Alfvenic currents and attendant energy dispersed, counterstreaming electrons poleward of the <span class="hlt">growth-phase</span> arc. The Alfvenic currents are locally planar structures with characteristic thicknesses on the order of a few tens of kilometers. In subsequent passages by the other spacecraft, the plasma sheet region became hotter and thicker via the injection of new hot, dense plasma of magnetospheric origins poleward of the pre-existing <span class="hlt">growth</span> <span class="hlt">phase</span> arc. In association with the heating and/or thickening of the plasma sheet, the currents appeared to broaden to larger scales as Alfven dominated activity gave way to either inverted-V dominated or mixed inverted-V and Alfvenic behavior depending on location. The transition from Alfven dominated to inverted-V dominated</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70034109','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70034109"><span>Spring-fall asymmetry of <span class="hlt">substorm</span> strength, geomagnetic activity and solar wind: Implications for semiannual variation and solar hemispheric asymmetry</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Mursula, K.; Tanskanen, E.; Love, J.J.</p> <p>2011-01-01</p> <p>We study the seasonal variation of <span class="hlt">substorms</span>, geomagnetic activity and their solar wind drivers in 1993-2008. The number of <span class="hlt">substorms</span> and <span class="hlt">substorm</span> mean duration depict an annual variation with maxima in Winter and Summer, respectively, reflecting the annual change of the local ionosphere. In contradiction, <span class="hlt">substorm</span> mean amplitude, <span class="hlt">substorm</span> total efficiency and global geomagnetic activity show a dominant annual variation, with equinoctial maxima alternating between Spring in solar cycle 22 and Fall in cycle 23. The largest annual variations were found in 1994 and 2003, in the declining <span class="hlt">phase</span> of the two cycles when high-speed streams dominate the solar wind. A similar, large annual variation is found in the solar wind driver of <span class="hlt">substorms</span> and geomagnetic activity, which implies that the annual variation of <span class="hlt">substorm</span> strength, <span class="hlt">substorm</span> efficiency and geomagnetic activity is not due to ionospheric conditions but to a hemispherically asymmetric distribution of solar wind which varies from one cycle to another. Our results imply that the overall semiannual variation in global geomagnetic activity has been seriously overestimated, and is largely an artifact of the dominant annual variation with maxima alternating between Spring and Fall. The results also suggest an intimate connection between the asymmetry of solar magnetic fields and some of the largest geomagnetic disturbances, offering interesting new pathways for forecasting disturbances with a longer lead time to the future. Copyright ?? 2011 by the American Geophysical Union.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.agu.org/pubs/crossref/2011/2011GL046751.shtml','USGSPUBS'); return false;" href="http://www.agu.org/pubs/crossref/2011/2011GL046751.shtml"><span>Spring-fall asymmetry of <span class="hlt">substorm</span> strength, geomagnetic activity and solar wind: Implications for semiannual variation and solar hemispheric asymmetry</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Marsula, K.; Tanskanen, E.; Love, J.J.</p> <p>2011-01-01</p> <p>We study the seasonal variation of <span class="hlt">substorms</span>, geomagnetic activity and their solar wind drivers in 1993–2008. The number of <span class="hlt">substorms</span> and <span class="hlt">substorm</span> mean duration depict an annual variation with maxima in Winter and Summer, respectively, reflecting the annual change of the local ionosphere. In contradiction, <span class="hlt">substorm</span> mean amplitude, <span class="hlt">substorm</span> total efficiency and global geomagnetic activity show a dominant annual variation, with equinoctial maxima alternating between Spring in solar cycle 22 and Fall in cycle 23. The largest annual variations were found in 1994 and 2003, in the declining <span class="hlt">phase</span> of the two cycles when high-speed streams dominate the solar wind. A similar, large annual variation is found in the solar wind driver of <span class="hlt">substorms</span> and geomagnetic activity, which implies that the annual variation of <span class="hlt">substorm</span> strength, <span class="hlt">substorm</span> efficiency and geomagnetic activity is not due to ionospheric conditions but to a hemispherically asymmetric distribution of solar wind which varies from one cycle to another. Our results imply that the overall semiannual variation in global geomagnetic activity has been seriously overestimated, and is largely an artifact of the dominant annual variation with maxima alternating between Spring and Fall. The results also suggest an intimate connection between the asymmetry of solar magnetic fields and some of the largest geomagnetic disturbances, offering interesting new pathways for forecasting disturbances with a longer lead time to the future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMSM43A1720Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMSM43A1720Z"><span>A Unified Scenario of Near-Earth <span class="hlt">Substorm</span> Onset: Analysis of THEMIS Events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhu, P.; Raeder, J.; Bhattacharjee, A.; Germaschewski, K.; Hegna, C.</p> <p>2008-12-01</p> <p>We propose an alternative scenario for the <span class="hlt">substorm</span> onset process, based on ideal ballooning stability analysis of the near-Earth plasma sheet during recent THEMIS <span class="hlt">substorm</span> events. In this scenario, the ballooning instability is initiated by the magnetic reconnection in the near-Earth plasma sheet, which in turn directly contributes to the trigger of a full onset. Using the solar wind data from WIND satellite observation for the <span class="hlt">substorm</span> event as an input at dayside, we reconstructed a sequence of global magnetospheric configurations around the <span class="hlt">substorm</span> onset by means of OpenGGCM simulation. These simulations have reproduced most of the salient features, including the onset timing, observed in the THEMIS <span class="hlt">substorm</span> events [Raeder et al, 2008]. The ballooning instability criterion and <span class="hlt">growth</span> rate are evaluated for the near-Earth plasma sheet region where the configuration satisfies a quasi-static equilibrium condition. Our analysis of the evolution of the near-Earth magnetotail region during the <span class="hlt">substorm</span> events reveals a correlation between the breaching of the ballooning stability condition and the <span class="hlt">substorm</span> onset in both temporal and spatial domains. The analysis suggests that the Earthward bulk plasma flow induced by the reconnection event in the near- Earth plasma sheet, leads to the pressure build-up and creates a favorable condition for the initiation of the ballooning instability in that same region. This new alternative scenario further elaborates earlier conjectures on the roles of reconnection and ballooning instability [Bhattacharjee et al, 1998], and has the potential to integrate both the near-Earth neutral-line model [McPherron et al, 1973] and the near-Earth current-sheet- disruption model [Lui et al, 1988] into a unified model of the near-Earth <span class="hlt">substorm</span> onset. Research supported by U.S. NSF Grant No. ATM-0542954.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990079791&hterms=IMF&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DIMF','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990079791&hterms=IMF&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DIMF"><span>Predictions of <span class="hlt">Substorms</span> and Intensifications Following Northward Turnings of the IMF</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Blanchard, G. T.; Lyons, L. R.; Spann, J.</p> <p>1999-01-01</p> <p><span class="hlt">Substorms</span> are often observed to occur at the end of intervals of Southward interplanetary magnetic field (IMF), i.e. following the northward turning. Despite the significant correlation between northward turning and <span class="hlt">substorms</span>, no direct causal relationship between northward turnings and <span class="hlt">substorms</span> has been demonstrated. Assuming such a causal relationship, we predict that <span class="hlt">substorms</span> will occur within a particular interval following the observation of a northward turning in the IMF. We observe 16 northward turnings following steady, southward IMF in data taken by the WIND spacecraft magnetic field instrument (MFI). To ensure that the northward turning was observed at the magnetosphere, we require that the northward turning also be observed by instruments on either one of Geotail or IMP-8 while the separation of the second spacecraft from WIND was more that 10 R(sub E). These two-spacecraft observations also allow us to predict more accurately the arrival time of the northward turning at the Earth. Of the predictions <span class="hlt">substorms</span>, 10 predictions were clearly successful to within +/- 12 min. Five predictions failed, but the failures reveal clear shortcomings in the criteria for a northward turning that we correct. The failures were caused by an increase in the absolute value of B(sub YGSM) simultaneous with the northward turning in 3 cases, and a weak southward IMF preceding the northward turning in 2 cases. The final northward turning arrived in the recovery <span class="hlt">phase</span> of an ongoing <span class="hlt">substorm</span>, and resulted in unusual auroral activity. The implication of the predictability of <span class="hlt">substorms</span> following sharp northward turnings is that the postulated causal relationship between northward turnings and <span class="hlt">substorm</span> onset exists. The effect of increases in the absolute value of B(sub YGSM) to negate the triggering ability of northward turnings suggests that the triggering mechanism involves sharp reductions in the magnetospheric convection electric field.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_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('https://ntrs.nasa.gov/search.jsp?R=19990079791&hterms=IMF&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DIMF','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990079791&hterms=IMF&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DIMF"><span>Predictions of <span class="hlt">Substorms</span> and Intensifications Following Northward Turnings of the IMF</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Blanchard, G. T.; Lyons, L. R.; Spann, J.</p> <p>1999-01-01</p> <p><span class="hlt">Substorms</span> are often observed to occur at the end of intervals of Southward interplanetary magnetic field (IMF), i.e. following the northward turning. Despite the significant correlation between northward turning and <span class="hlt">substorms</span>, no direct causal relationship between northward turnings and <span class="hlt">substorms</span> has been demonstrated. Assuming such a causal relationship, we predict that <span class="hlt">substorms</span> will occur within a particular interval following the observation of a northward turning in the IMF. We observe 16 northward turnings following steady, southward IMF in data taken by the WIND spacecraft magnetic field instrument (MFI). To ensure that the northward turning was observed at the magnetosphere, we require that the northward turning also be observed by instruments on either one of Geotail or IMP-8 while the separation of the second spacecraft from WIND was more that 10 R(sub E). These two-spacecraft observations also allow us to predict more accurately the arrival time of the northward turning at the Earth. Of the predictions <span class="hlt">substorms</span>, 10 predictions were clearly successful to within +/- 12 min. Five predictions failed, but the failures reveal clear shortcomings in the criteria for a northward turning that we correct. The failures were caused by an increase in the absolute value of B(sub YGSM) simultaneous with the northward turning in 3 cases, and a weak southward IMF preceding the northward turning in 2 cases. The final northward turning arrived in the recovery <span class="hlt">phase</span> of an ongoing <span class="hlt">substorm</span>, and resulted in unusual auroral activity. The implication of the predictability of <span class="hlt">substorms</span> following sharp northward turnings is that the postulated causal relationship between northward turnings and <span class="hlt">substorm</span> onset exists. The effect of increases in the absolute value of B(sub YGSM) to negate the triggering ability of northward turnings suggests that the triggering mechanism involves sharp reductions in the magnetospheric convection electric field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920064858&hterms=origin+Research&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dorigin%2BResearch','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920064858&hterms=origin+Research&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dorigin%2BResearch"><span>Advances in magnetospheric storm and <span class="hlt">substorm</span> research - 1989-1991</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.</p> <p>1992-01-01</p> <p>Recent advances in magnetospheric storm and <span class="hlt">substorm</span> research is reviewed, with emphasis on how the large southward fields and high velocities produced in the solar wind influence the magnetosphere and cause the enhanced transfer of energy, momentum, and mass to the magnetosphere. Overwhelming evidence indicates that the southward interplanetary magnetic field is the primary controlling factor in the generation of <span class="hlt">substorms</span>. The immediate cause of the expansion <span class="hlt">phase</span> onset is controversial, but the suddenness of the onset is suggestive of an instability that disrupts the cross-tail currents. Measurements increasingly suggest the region of 7-10 R sub E near midnight as the likely point of origin, but it is not clear that the long-popular tearing mode can go unstable this close to the earth, where it may be stabilized by a small northward field component.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E1946T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E1946T"><span>Extremely Intense Magnetospheric <span class="hlt">Substorms</span> : External Triggering? Preconditioning?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsurutani, Bruce; Echer, Ezequiel; Hajra, Rajkumar</p> <p>2016-07-01</p> <p>We study particularly intense <span class="hlt">substorms</span> using a variety of near-Earth spacecraft data and ground observations. We will relate the solar cycle dependences of events, determine whether the supersubstorms are externally or internally triggered, and their relationship to other factors such as magnetospheric preconditioning. If time permits, we will explore the details of the events and whether they are similar to regular (Akasofu, 1964) <span class="hlt">substorms</span> or not. These intense <span class="hlt">substorms</span> are an important feature of space weather since they may be responsible for power outages.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920048656&hterms=1054&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2526%25231054','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920048656&hterms=1054&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2526%25231054"><span>Magnetic islands in the near geomagnetic tail and its implications for the mechanism of 1054 UT CDAW 6 <span class="hlt">substorm</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lin, N.; Walker, R. J.; Mcpherron, R. L.; Kivelson, M. G.</p> <p>1990-01-01</p> <p>During the 1054 UT CDAW 6 <span class="hlt">substorm</span> event, two ISEE spacecraft observed dynamic changes in the magnetic field and in the flux of energetic particles in the near-earth plasma sheet. In the <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phase</span>, the magnetic field at both ISEE spacecraft became tail-like. Following expansion <span class="hlt">phase</span> onset, two small scale magnetic islands were observed moving tailward at a velocity of about 580 km/s. The passage of these two magnetic islands was coincident with bursts of tailward streaming energetic particles. The length of the magnetic loops was estimated to have been about 2 to 3 earth radii while the height of the loops was less than 0.5 earth radii. The magnetic islands were produced by multipoint reconnection processes in the near tail plasma sheet which may have been associated with the formation of the near-earth neutral line and the subsequent formation of a large scale plasmoid. The near-earth neutral line retreated tailward later in the expansion <span class="hlt">phase</span>, as suggested by the reversal of the streaming of energetic particles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19810016430','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19810016430"><span>Vapor <span class="hlt">phase</span> diamond <span class="hlt">growth</span> technology</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Angus, J. C.</p> <p>1981-01-01</p> <p>Ion beam deposition chambers used for carbon film generation were designed and constructed. Features of the developed equipment include: (1) carbon ion energies down to approx. 50 eV; (2) in suit surface monitoring with HEED; (3) provision for flooding the surface with ultraviolet radiation; (4) infrared laser heating of substrate; (5) residual gas monitoring; (6) provision for several source gases, including diborane for doping studies; and (7) <span class="hlt">growth</span> from either hydrocarbon source gases or from carbon/argon arc sources. Various analytical techniques for characterization of from carbon/argon arc sources. Various analytical techniques for characterization of the ion deposited carbon films used to establish the nature of the chemical bonding and crystallographic structure of the films are discussed. These include: H2204/HN03 etch; resistance measurements; hardness tests; Fourier transform infrared spectroscopy; scanning auger microscopy; electron spectroscopy for chemical analysis; electron diffraction and energy dispersive X-ray analysis; electron energy loss spectroscopy; density measurements; secondary ion mass spectroscopy; high energy electron diffraction; and electron spin resonance. Results of the tests are summarized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950059021&hterms=triggers+alone&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dtriggers%2Balone','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950059021&hterms=triggers+alone&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dtriggers%2Balone"><span>Does the ballooning instability trigger <span class="hlt">substorms</span> in the near-Earth magnetotail?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ohtani, Shin-Ichi; Tamao, Tsutomu</p> <p>1993-01-01</p> <p>The stability of the near-Earth magnetotail against ballooning (or configurational) instability is examined in the framework of the MHD approximation. It is emphasized that a change in plasma pressure induced by a meriodional electric field drift delta u(sub n) is an important factor that determines the stability. We have to consider two ways in which plasma pressure changes, that is, a convective change -delta u(sub n) grad(P(sub 0)), where P(sub 0) is background plasma pressure, and plasma expansion/compression -P(sub 0) dive (delta u(sub n)). Since delta u(sub n) is perpendicular to the magnetic field and its magnitude is inversely proportional to the magnetic field strength, delta u(sub n) diverges/converges in usual tail magnetic field configurations. For the instability, the convective change must overwhelm the effects of the plasma expansion/compression. However, near the equator in the near-Earth tail, the latter may overcompensate for the former. We describe the ballooning instability in terms of a coupling between the Alfven and slow magnetosonic waves in an inhomogeneous plasma and derive instability conditions. The result shows that the excessive curvature stabilizes, rather than destabilizes, perturbations. It is also found that the field-aligned flow stabilizes perturbations, as well as the field-aligned current. We infer that under quiet conditions, the plasma pressure gradient in the near-Earth tail is not sharp enough to trigger the instability. The plasma sheet is expected to become more stable during the <span class="hlt">substorm</span> <span class="hlt">growth</span> <span class="hlt">phase</span> because of an increase in the field line curvature associated with the plasma sheet thinning. In the region closer to the Earth, including the ring current, the plasma pressure gradient may be localized in a limited range of the radial distance during the <span class="hlt">growth</span> <span class="hlt">phase</span>. However, recently reported plasma and magnetic field parameters before <span class="hlt">substorm</span> onsets do not provide very convincing evidence that the ballooning instability</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GMS...207..361K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GMS...207..361K"><span><span class="hlt">Substorm</span> Current Wedge at Earth and Mercury</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kepko, L.; Glassmeier, K.-H.; Slavin, J. A.; Sundberg, T.</p> <p>2015-01-01</p> <p>This chapter reviews magnetospheric <span class="hlt">substorms</span> and dipolarizations observed at both Earth and Mercury. It briefly discusses new insights into the physics of the <span class="hlt">substorm</span> current wedge (SCW) that have been revealed the past few years. The formation and evolution of the SCW are closely tied to the braking of flows convecting flux away from the reconnection site and the resultant near-planet flux pileup that creates the dipolarization. At Earth, the SCW plays a critical role in <span class="hlt">substorms</span>, coupling magnetospheric to ionospheric motions, deflecting incoming plasma flows, and regulating the dissipation of pressure built up in the near-Earth magnetosphere during dipolarization. The lack of a conducting boundary at Mercury provides a natural experiment to examine the role of an ionosphere on regulating magnetospheric convection. Energetic particles may play a much greater role within <span class="hlt">substorms</span> at Mercury than at Earth, providing another opportunity for comparative studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRA..119.9834C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRA..119.9834C"><span>A superposed epoch analysis of the regions 1 and 2 Birkeland currents observed by AMPERE during <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Coxon, J. C.; Milan, S. E.; Clausen, L. B. N.; Anderson, B. J.; Korth, H.</p> <p>2014-12-01</p> <p>We perform a superposed epoch analysis of the evolution of the Birkeland currents (field-aligned currents) observed by the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) during <span class="hlt">substorms</span>. The study is composed of 2900 <span class="hlt">substorms</span> provided by the SuperMAG experiment. We find that the current ovals expand and contract over the course of a <span class="hlt">substorm</span> cycle and that currents increase in magnitude approaching <span class="hlt">substorm</span> onset and are further enhanced in the expansion <span class="hlt">phase</span>. Subsequently, we categorize the <span class="hlt">substorms</span> by their onset latitude, a proxy for the amount of open magnetic flux in the magnetosphere, and find that Birkeland currents are significantly higher throughout the epoch for low-latitude <span class="hlt">substorms</span>. Our results agree with previous studies which indicate that <span class="hlt">substorms</span> are more intense and close more open magnetic flux when the amount of open flux is larger at onset. We place these findings in the context of previous work linking dayside and nightside reconnection rate to Birkeland current strengths and locations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990078594&hterms=IMF&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DIMF','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990078594&hterms=IMF&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DIMF"><span>On the Predictability of <span class="hlt">Substorms</span> Following Sharp Northward Turnings of the IMF</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Blanchard, G. T.; Lyons, Larry R.; Spann, James F., Jr.; Reeves, G. D.</p> <p>1998-01-01</p> <p>It has been shown that there is an association between changes of the interplanetary magnetic field (IMF) that are expected to lead to a reduction in magnetospheric convection (northward turnings, reductions) and the onset of the expansion <span class="hlt">phase</span> of <span class="hlt">substorms</span>. This has been previously demonstrated by analyses of IMF data during time intervals associated with identified <span class="hlt">substorm</span> onsets. Here we examine whether observations of northward turnings of the IMF can be used to predict the occurrence of <span class="hlt">substorms</span>. We first identified sharp northward turnings that follow an interval of steady, southward IMF using measurements from the Wind spacecraft during the first 180 days of 1997. We also required that the northward turning be observed by either IMP-8 or GEOTAIL, in addition to Wind, and that one of the observing satellites be sufficiently close to the Earth-Sun line, or that the two observing satellites be sufficiently separated, that we are reasonably certain that the northward turning affected the magnetosphere. We also used the dual observations to estimate the arrival of the northward turning at the Earth. Using these criteria, we predicted 17 <span class="hlt">substorms</span>. We then searched for the following signatures of <span class="hlt">substorm</span> onset around the time of the predicted onset: auroral brightening followed by auroral bulge expansion observed by Polar UVI, geosynchronous particle injection, geosynchronous magnetic field dipolarization, and an appropriate magnetic disturbance at the surface of the Earth. Of the 17 predictions of <span class="hlt">substorms</span>, 10 were successful in that a <span class="hlt">substorm</span> onset was observed within 12 min of the predicted onset, 1 is indeterminate due to a lack of data at the Earth, 1 had unusual activity that we have not been able to identify, and 5 were unsuccessful. The failure of these last 5 predictions is explicable. Two of the northward turnings that failed to produce <span class="hlt">substorms</span> were preceded by the lowest average of the set. The remaining 3 were the only cases in which the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998PhPl....5.2001B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998PhPl....5.2001B"><span>Dynamics of thin current sheets and their disruption by ballooning instabilities: A mechanism for magnetospheric <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bhattacharjee, A.; Ma, Z. W.; Wang, Xiaogang</p> <p>1998-05-01</p> <p>Multipoint satellite observations indicate the development of thin current sheets and an impulsive intensification of the cross-tail current density in the <span class="hlt">growth</span> <span class="hlt">phase</span> at near-earth distances during a short interval (<1 min) just before onset, after a period of sluggish <span class="hlt">growth</span> (˜0.5-1.5 h). These multiple time scales are accounted for by analysis and two-dimensional magnetohydrodynamic simulation of the magnetotail in the high-Lundquist number regime, including the earth's dipole field. In the slow <span class="hlt">growth</span> <span class="hlt">phase</span>, a thin current sheet develops spanning Y points that stretch from the midtail region (˜30RE) to the near-earth region (˜10RE). This is followed by an impulsive enhancement in the current sheet amplitude due to flux pileup, consistent with observations. The stretched magnetotail with an embedded thin current sheet is found to be unstable to an ideal compressible ballooning instability with rapid spatial variation in the dawn-dusk direction. The linear instability is demonstrated by numerical solutions of the ideal ballooning eigenmode equation for a sequence of two-dimensional magnetotail configurations containing a thin current sheet, realized during the impulsive <span class="hlt">growth</span> <span class="hlt">phase</span>. Line-tied boundary conditions are imposed at the ionosphere, and shown to have a strong influence on the linear stability of ballooning modes at near-earth distances. It is suggested that the ideal ballooning instability provides a possible mechanism for disrupting the cross-tail current at <span class="hlt">substorm</span> onset.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20100002035&hterms=darkness&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Ddarkness','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20100002035&hterms=darkness&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Ddarkness"><span>Hemispheric Asymmetries in <span class="hlt">Substorm</span> Recovery Time Scales</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fillingim, M. O.; Chua, D H.; Germany, G. A.; Spann, James F.</p> <p>2009-01-01</p> <p>Previous statistical observations have shown that the recovery time scales of <span class="hlt">substorms</span> occurring in the winter and near equinox (when the nighttime auroral zone was in darkness) are roughly twice as long as the recovery time scales for <span class="hlt">substorms</span> occurring in the summer (when the nighttime auroral region was sunlit). This suggests that auroral <span class="hlt">substorms</span> in the northern and southern hemispheres develop asymmetrically during solstice conditions with <span class="hlt">substorms</span> lasting longer in the winter (dark) hemisphere than in the summer (sunlit) hemisphere. Additionally, this implies that more energy is deposited by electron precipitation in the winter hemisphere than in the summer one during <span class="hlt">substorms</span>. This result, coupled with previous observations that have shown that auroral activity is more common when the ionosphere is in darkness and is suppressed when the ionosphere is in daylight, strongly suggests that the ionospheric conductivity plays an important role governing how magnetospheric energy is transferred to the ionosphere during <span class="hlt">substorms</span>. Therefore, the ionosphere itself may dictate how much energy it will accept from the magnetosphere during <span class="hlt">substorms</span> rather than this being an externally imposed quantity. Here, we extend our earlier work by statistically analyzing the recovery time scales for a large number of <span class="hlt">substorms</span> observed in the conjugate hemispheres simultaneously by two orbiting global auroral imagers: Polar UVI and IMAGE FUV. Our current results are consistent with previous observations. The recovery time scales are observed to be longer in the winter (dark) hemisphere while the auroral activity has a shorter duration in the summer (sunlit) hemisphere. This leads to an asymmetric energy input from the magnetosphere to the ionosphere with more energy being deposited in the winter hemisphere than in the summer hemisphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19520943','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19520943"><span>Comment on "Tail reconnection triggering <span class="hlt">substorm</span> onset".</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lui, A T Y</p> <p>2009-06-12</p> <p>Angelopoulos et al. (Research Articles, 15 August 2008, p. 931) reported that magnetic reconnection in Earth's magnetotail triggered the onset of a magnetospheric <span class="hlt">substorm</span>. We provide evidence that (i) near-Earth current disruption, occurring before the conventional tail reconnection signatures, triggered the onset; (ii) the observed auroral intensification and tail reconnection are not causally linked; and (iii) the onset they identified is a continuation of earlier <span class="hlt">substorm</span> activities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20100002035&hterms=time+work&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dtime%2Bwork','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20100002035&hterms=time+work&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dtime%2Bwork"><span>Hemispheric Asymmetries in <span class="hlt">Substorm</span> Recovery Time Scales</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fillingim, M. O.; Chua, D H.; Germany, G. A.; Spann, James F.</p> <p>2009-01-01</p> <p>Previous statistical observations have shown that the recovery time scales of <span class="hlt">substorms</span> occurring in the winter and near equinox (when the nighttime auroral zone was in darkness) are roughly twice as long as the recovery time scales for <span class="hlt">substorms</span> occurring in the summer (when the nighttime auroral region was sunlit). This suggests that auroral <span class="hlt">substorms</span> in the northern and southern hemispheres develop asymmetrically during solstice conditions with <span class="hlt">substorms</span> lasting longer in the winter (dark) hemisphere than in the summer (sunlit) hemisphere. Additionally, this implies that more energy is deposited by electron precipitation in the winter hemisphere than in the summer one during <span class="hlt">substorms</span>. This result, coupled with previous observations that have shown that auroral activity is more common when the ionosphere is in darkness and is suppressed when the ionosphere is in daylight, strongly suggests that the ionospheric conductivity plays an important role governing how magnetospheric energy is transferred to the ionosphere during <span class="hlt">substorms</span>. Therefore, the ionosphere itself may dictate how much energy it will accept from the magnetosphere during <span class="hlt">substorms</span> rather than this being an externally imposed quantity. Here, we extend our earlier work by statistically analyzing the recovery time scales for a large number of <span class="hlt">substorms</span> observed in the conjugate hemispheres simultaneously by two orbiting global auroral imagers: Polar UVI and IMAGE FUV. Our current results are consistent with previous observations. The recovery time scales are observed to be longer in the winter (dark) hemisphere while the auroral activity has a shorter duration in the summer (sunlit) hemisphere. This leads to an asymmetric energy input from the magnetosphere to the ionosphere with more energy being deposited in the winter hemisphere than in the summer hemisphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.3577G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.3577G"><span>The three dimensional current system during <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gjerloev, Jesper; Hoffman, Robert</p> <p>2013-04-01</p> <p>We present results from a comprehensive statistical study of the ionospheric current system and it's coupling to the magnetosphere during classical bulge type <span class="hlt">substorms</span>. We identified 116 <span class="hlt">substorms</span> and determined the global ionospheric current system before and during the <span class="hlt">substorm</span> using the SuperMAG initiative and global auroral images obtained by the Polar VIS Earth camera. The westward electrojet (WEJ) is centered around 65 / 72 deg magnetic latitude post-midnight / pre-midnight. Thus, we find a distinct latitudinal shift between the locations of the westward electrojet at these local times. The spatiotemporal behavior of the WEJ differs at these two local times. Attempting to explain this significant finding we propose two possible simple current systems. 1) The classical <span class="hlt">substorm</span> current wedge, which is a single 3D current system. The distinct poleward kink and the different spatiotemporal behavior, however, present considerable complications for this solution. 2) A new 3D current system that consists of 2 wedge type systems: the classical <span class="hlt">substorm</span> current wedge in the pre-midnight region and another current wedge in the post-midnight region. The latter maps to the inner magnetosphere. To support the empirical modeling we performed Biot and Savart integrations to simulate the ground perturbations. We present results of the statistical study, show typical events, results from the simulations, and discuss the implications for our understanding of the 3D current system associated with <span class="hlt">substorms</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17..848K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17..848K"><span>Jumps of the solar wind direction and the <span class="hlt">substorm</span> probability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kubyshkina, Daria; Kubyshkina, Marina; Semenov, Vladimir</p> <p>2015-04-01</p> <p>Magnetospheric <span class="hlt">substorm</span> commonly supposed to consist of two stages, loading and unloading. During the first stage the magnetic energy is stored in the magnetotail, which leads to increasing of the magnetic field intensity in the lobes and electric currents in the plasma sheet. The next uloading stage usually related to the reconnection process, which releases accumulated magnetic energy and produces the bursty bulk flows (BBFs) in the magnetotail. Such a scheme has been confirmed from both experimental and theoretical points of view. The weakest point of this scheme is the physical conditions which are necessary for the onset of the reconnection, but although the huge number of investigations was made to this end. Among them <span class="hlt">substorm</span> triggers such as pressure pulses, turning of the interplanetary magnetic field (IMF) to the north direction and so on. We would like to emphasize the role of the bent current sheets first proposed by Kivelson and Hughes in 1990. The idea is that in the asymmetric configurations gradients and current density <span class="hlt">growth</span>, so these conditions are supposed to be favorable for the reconnection. Then the minimal stress of the system can lead to the <span class="hlt">substorm</span> onset. In the presented study we have analyzed the possibility of the current sheet asymmetry to be the trigger in theory and in observations (by statistical analysis of <span class="hlt">substorm</span> occurrences). The bent of the current sheet can be produced by different sources. The most evident of them are the dipole tilt angle variations and the changes of the solar wind direction. The first source, tilt variations, are slow, so in the current study we at first analyzed the fast changes of the solar wind. The experimental analysis includes the investigation of the number of the events against dipole tilt angle and the solar wind direction, which both produce the distortion and inclination of the dipole current sheet. Theoretical investigation of this issue is based on the analysis of the quasi</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010cosp...38.1973D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010cosp...38.1973D"><span>Modeling of <span class="hlt">substorm</span> development with a kinematic effect by the global MHD simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>den, Mitsue; Fujita, Shigeru; Tanaka, Takashi; Horiuchi, Ritoku</p> <p></p> <p>Magnetic reconnection is considered to play an important role in space phenomena such as <span class="hlt">substorm</span> in the Earth's magnetosphere. Recently, Tanaka and Fujita reproduced <span class="hlt">substorm</span> evoution process by numerical simulation with the global MHD code. In the MHD framework, the dissipation model is used for modeling of the kinetic effects. They found that the normalized reconnection viscosity, one of the dessipation model employed there, gave a large effect for the <span class="hlt">substorm</span> development though that viscosity was assumed to be a constant parameter. It is well known that magnetric reconnection is controlled by microscopic kinetic mechanism. Horiuchi et al. investigated the roles of microscopic plasma instabilities on the violation of the frozen-in condition by examining the force balance equation based on explicit electromagnetic particle simulation for an ion-scale current sheet, and concluded that the <span class="hlt">growth</span> of drift kink instability can create anomalous resistivity leading to the excitation of collisionless reconnection. They estimated the effective resistivity based on the particle simulation data. In this paper, we perform <span class="hlt">substorm</span> simulation by using the global MHD code with this anomalous resistivity obtained in their microscopic approach istead of the emprical resistivity model, and investigate the relationship between the <span class="hlt">substorm</span> development and the anomalous resistivity model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatSR...632362H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatSR...632362H"><span>Response of plasmaspheric configuration to <span class="hlt">substorms</span> revealed by Chang’e 3</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>He, Han; Shen, Chao; Wang, Huaning; Zhang, Xiaoxin; Chen, Bo; Yan, Jun; Zou, Yongliao; Jorgensen, Anders M.; He, Fei; Yan, Yan; Zhu, Xiaoshuai; Huang, Ya; Xu, Ronglan</p> <p>2016-08-01</p> <p>The Moon-based Extreme Ultraviolet Camera (EUVC) of the Chang’e 3 mission provides a global and instantaneous meridian view (side view) of the Earth’s plasmasphere. The plasmasphere is one inner component of the whole magnetosphere, and the configuration of the plasmasphere is sensitive to magnetospheric activity (storms and <span class="hlt">substorms</span>). However, the response of the plasmaspheric configuration to <span class="hlt">substorms</span> is only partially understood, and the EUVC observations provide a good opportunity to investigate this issue. By reconstructing the global plasmaspheric configuration based on the EUVC images observed during 20–22 April 2014, we show that in the observing period, the plasmasphere had three bulges which were located at different geomagnetic longitudes. The inferred midnight transit times of the three bulges, using the rotation rate of the Earth, coincide with the expansion <span class="hlt">phase</span> of three <span class="hlt">substorms</span>, which implies a causal relationship between the <span class="hlt">substorms</span> and the formation of the three bulges on the plasmasphere. Instead of leading to plasmaspheric erosion as geomagnetic storms do, <span class="hlt">substorms</span> initiated on the nightside of the Earth cause local inflation of the plasmasphere in the midnight region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27576944','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27576944"><span>Response of plasmaspheric configuration to <span class="hlt">substorms</span> revealed by Chang'e 3.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>He, Han; Shen, Chao; Wang, Huaning; Zhang, Xiaoxin; Chen, Bo; Yan, Jun; Zou, Yongliao; Jorgensen, Anders M; He, Fei; Yan, Yan; Zhu, Xiaoshuai; Huang, Ya; Xu, Ronglan</p> <p>2016-08-31</p> <p>The Moon-based Extreme Ultraviolet Camera (EUVC) of the Chang'e 3 mission provides a global and instantaneous meridian view (side view) of the Earth's plasmasphere. The plasmasphere is one inner component of the whole magnetosphere, and the configuration of the plasmasphere is sensitive to magnetospheric activity (storms and <span class="hlt">substorms</span>). However, the response of the plasmaspheric configuration to <span class="hlt">substorms</span> is only partially understood, and the EUVC observations provide a good opportunity to investigate this issue. By reconstructing the global plasmaspheric configuration based on the EUVC images observed during 20-22 April 2014, we show that in the observing period, the plasmasphere had three bulges which were located at different geomagnetic longitudes. The inferred midnight transit times of the three bulges, using the rotation rate of the Earth, coincide with the expansion <span class="hlt">phase</span> of three <span class="hlt">substorms</span>, which implies a causal relationship between the <span class="hlt">substorms</span> and the formation of the three bulges on the plasmasphere. Instead of leading to plasmaspheric erosion as geomagnetic storms do, <span class="hlt">substorms</span> initiated on the nightside of the Earth cause local inflation of the plasmasphere in the midnight region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5006020','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5006020"><span>Response of plasmaspheric configuration to <span class="hlt">substorms</span> revealed by Chang’e 3</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>He, Han; Shen, Chao; Wang, Huaning; Zhang, Xiaoxin; Chen, Bo; Yan, Jun; Zou, Yongliao; Jorgensen, Anders M.; He, Fei; Yan, Yan; Zhu, Xiaoshuai; Huang, Ya; Xu, Ronglan</p> <p>2016-01-01</p> <p>The Moon-based Extreme Ultraviolet Camera (EUVC) of the Chang’e 3 mission provides a global and instantaneous meridian view (side view) of the Earth’s plasmasphere. The plasmasphere is one inner component of the whole magnetosphere, and the configuration of the plasmasphere is sensitive to magnetospheric activity (storms and <span class="hlt">substorms</span>). However, the response of the plasmaspheric configuration to <span class="hlt">substorms</span> is only partially understood, and the EUVC observations provide a good opportunity to investigate this issue. By reconstructing the global plasmaspheric configuration based on the EUVC images observed during 20–22 April 2014, we show that in the observing period, the plasmasphere had three bulges which were located at different geomagnetic longitudes. The inferred midnight transit times of the three bulges, using the rotation rate of the Earth, coincide with the expansion <span class="hlt">phase</span> of three <span class="hlt">substorms</span>, which implies a causal relationship between the <span class="hlt">substorms</span> and the formation of the three bulges on the plasmasphere. Instead of leading to plasmaspheric erosion as geomagnetic storms do, <span class="hlt">substorms</span> initiated on the nightside of the Earth cause local inflation of the plasmasphere in the midnight region. PMID:27576944</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950045388&hterms=education+coexistence&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Deducation%2Bcoexistence','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950045388&hterms=education+coexistence&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Deducation%2Bcoexistence"><span>Ground-based studies of ionospheric convection associated with <span class="hlt">substorm</span> expansion</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kamide, Y.; Richmond, A. D.; Emery, B. A.; Hutchins, C. F.; Ahn, B.-H.; De La Beaujardiere, O.; Foster, J. C.; Heelis, R. A.; Kroehl, H. W.; Rich, F. J.</p> <p>1994-01-01</p> <p>The instantaneous patterns of electric fields and currents in the high-latitude ionosphere are deduced by combining satellite and radar measurements of the ionospheric drift velocity, along with ground-based magnetometer observations for October 25, 1981. The period under study was characterized by a relatively stable southward interplanetary magnetic field (IMF), so that the obtained electric field patterns do reflect, in general, the state of sustained and enhanced plasma convection in the magnetosphere. During one of the satellite passes, however, an intense westward electrojet caused by a <span class="hlt">substorm</span> intruded into the satellite (DE2) and radar (Chatanika, Alaska) field of view in the premidnight sector, providing a unique opportunity to differentiate the enhanced convection and <span class="hlt">substorm</span> expansion fields. The distributions of the calculated electric potential for the expansion and maximum <span class="hlt">phases</span> of the <span class="hlt">substorm</span> show the first clear evidence of the coexistence of two physically different systems in the global convection pattern. The changes in the convection pattern during the <span class="hlt">substorm</span> indicate that the large-scale potential distributions are indeed of general two-cell patterns representing the southward IMF status, but the night-morning cell has two positive peaks, one in the midnight sector and the other in the late morning hours, corresponding to the <span class="hlt">substorm</span> expansion and the convection enhancement, respectively.</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('https://ntrs.nasa.gov/search.jsp?R=19850041178&hterms=Storage+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DStorage%2Benergy','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850041178&hterms=Storage+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DStorage%2Benergy"><span>Magnetotail energy storage and release during the CDAW 6 <span class="hlt">substorm</span> analysis intervals</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Baker, D. N.; Fritz, T. A.; Mcpherron, R. L.; Fairfield, D. H.; Kamide, Y.; Baumjohann, W.</p> <p>1985-01-01</p> <p>The concept of the Coordinated Data Analysis Workshop (CDAW) grew out of the International Magnetospheric Study (IMS) program. According to this concept, data are to be pooled from a wide variety of spacecraft and ground-based sources for limited time intervals. These data are to provide the basis for the performance of very detailed correlative analyses, usually with fairly limited physical problems in mind. However, in the case of the CDAW 6 truly global goals are involved. The primary goal is to trace the flow of energy from the solar wind through the magnetosphere to its ultimate dissipation by <span class="hlt">substorm</span> processes. The present investigation has the specific goal to examine the evidence for the storage of solar wind energy in the magnetotail prior to <span class="hlt">substorm</span> expansion <span class="hlt">phase</span> onsets. Of particular interest is the determination, in individual <span class="hlt">substorm</span> cases, of the time delays between the loading of energy into the magnetospheric system and the subsequent unloading of this energy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001JASTP..63.1609L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001JASTP..63.1609L"><span><span class="hlt">Substorm</span> development as observed by Interball UV imager and 2-D magnetic array</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lyatsky, W.; Cogger, L. L.; Jackel, B.; Hamza, A. M.; Hughes, W. J.; Murr, D.; Rasmussen, O.</p> <p>2001-10-01</p> <p>Results of the study of two <span class="hlt">substorms</span> from Interball auroral UV measurements and two-dimensional patterns of equivalent ionospheric currents derived from the MACCS/CANOPUS and Greenland magnetometer arrays are presented. <span class="hlt">Substorm</span> development in 2-D equivalent ionospheric current patterns may be described in terms of the formation of two vortices in the equivalent currents: a morning vortex related to downward field-aligned current and an evening vortex related to upward field-aligned current. Poleward propagation of the magnetic disturbances during <span class="hlt">substorm</span> expansive <span class="hlt">phase</span> was found to be associated mainly with a poleward displacement of the morning vortex, whereas the evening vortex remained approximately at the same position. As a result, the initial quasi-azimuthal separation of the vortices was replaced by their quasi-meridional separation at <span class="hlt">substorm</span> maximum. Interball UV images during this period showed the formation of a bright auroral border at the poleward edge of <span class="hlt">substorm</span> auroral bulge. The auroral UV images showed also that the auroral distribution in the region between the polar border and the main auroral oval tends to have a form of bubbles or petals growing from a bright protuberant region on the equatorward boundary of the auroral oval. However, the resolution of the UV imager was not sufficient for the reliable separation of such the structures, therefore, this result should be considered as preliminary. Overlapping of the auroral UV images onto equivalent current patterns shows that the bright <span class="hlt">substorm</span> surge was well collocated with the evening vortex whereas the poleward auroral border did not coincide with any evident feature in equivalent ionospheric currents and was located several degrees equatorward of the morning current vortex center related to downward field-aligned current. The ground-based magnetic array allowing us to obtain instantaneous patterns of equivalent ionospheric currents gives a possibility to propose a new index for</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..121.3978H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..121.3978H"><span>The "Alfvénic surge" at <span class="hlt">substorm</span> onset/expansion and the formation of "Inverted Vs": Cluster and IMAGE observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hull, A. J.; Chaston, C. C.; Frey, H. U.; Fillingim, M. O.; Goldstein, M. L.; Bonnell, J. W.; Mozer, F. S.</p> <p>2016-05-01</p> <p>From multipoint, in situ observations and imaging, we reveal the injection-powered, Alfvénic nature of auroral acceleration during onset and expansion of a <span class="hlt">substorm</span>. It is shown how Alfvénic variations over time dissipate to form large-scale, inverted-V structures characteristic of quasistatic aurora. This characterization is made possible through the fortuitous occurrence of a <span class="hlt">substorm</span> onset and expansion <span class="hlt">phase</span> on field lines traversed by Cluster in the high-altitude acceleration region. <span class="hlt">Substorm</span> onset was preceded by the occurrence of multiple poleward boundary intensifications (PBIs) and subsequent development/progression of a streamer toward the <span class="hlt">growth</span> <span class="hlt">phase</span> arc indicating that this is of the PBI-/streamer-triggered class of <span class="hlt">substorms</span>. Onset on Cluster is marked by the injection of hot, dense magnetospheric plasma in a region tied to one of the preexisting PBI current systems. This was accompanied by a surge of Alfvénic activity and enhanced inverted-V acceleration, as the PBI current system intensified and striated to dispersive scale Alfvén waves. The <span class="hlt">growth</span> of Alfvén wave activity was significant (up to a factor of 300 increase in magnetic field power spectral density at frequencies 20 mHz ≲f≲ few hertz) and coincided with moderate <span class="hlt">growth</span> (factor 3-5) in the background PBI current. This sequence is indicative of a cascade process whereby small-scale/dispersive Alfvén waves are generated from large-scale Alfvén waves or current destabilization. It also demonstrates that the initial PBIs and their subsequent evolution are an intrinsic part of the global auroral <span class="hlt">substorm</span> response to injection and accompanying wave energy input from the magnetotail. Alfvénic activity persisted poleward of the PBI currents composing a broad Alfvén wave-dominated region extending to the polar cap edge. These waves have transverse scales ranging from a few tens of kilometers to below the ion gyroradius and are associated with large electric fields (up to 200 mV/m) and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFMSM14A..06P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFMSM14A..06P"><span>Storm-Time <span class="hlt">Substorms</span> and Sawtooth Events: Test for <span class="hlt">Substorm</span> Models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pulkkinen, T. I.; Tanskanen, E. I.; Reeves, G. D.; Donovan, E.; Singer, H. J.; Slavin, J. A.</p> <p>2005-12-01</p> <p>A <span class="hlt">substorm</span> search engine is used to identify <span class="hlt">substorm</span> onsets that occur during magnetic storms in the period 2001-2004. Each <span class="hlt">substorm</span> is analyzed in detail using several parameters to classify the events. Peak amplitude of the <span class="hlt">substorm</span> is defined from the AL-index. Existence and type of energetic particle injections are determined from the LANL energetic ion and electron data. Tail magnetic field measurements (GOES, Cluster, Geotail) are used to infer whether a thin current sheet was formed prior to the <span class="hlt">substorm</span> onset. Latitudinal magnetometer chains (CANOPUS, IMAGE) are used to determine whether the main expansion direction was poleward or equatorward. Possible triggers for the onset and intensity of the driving electric field are identified from the solar wind and interplanetary magnetic field measurements (ACE, WIND). The goal of the study is to statistically examine to what extent the stormtime <span class="hlt">substorms</span> show signatures typically associated classical non-storm <span class="hlt">substorms</span> and to what extent the activity is characteristic only of storm periods. Furthermore, the goal is to identify the "sawtooth events" from the data set, and examine whether the activation characteristics differ from the other stormtime activations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950035956&hterms=Ramon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D40%26Ntt%3DRamon','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950035956&hterms=Ramon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D40%26Ntt%3DRamon"><span>Evidence for particle acceleration during magnetospheric <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lopez, Ramon E.; Baker, Daniel N.</p> <p>1994-01-01</p> <p>Magnetospheric <span class="hlt">substorms</span> represent the episodic dissipation of energy stored in the geomagnetic tail that was previously extracted from the solar wind. This energy release produces activity throughout the entire magnetosphere-ionosphere system, and it results in a wide variety of phenomena such as auroral intensifications and the generation of new current systems. All of these phenomena involve the acceleration of particles, sometimes up to several MeV. We present a brief overview of <span class="hlt">substorm</span> phenomenology. We then review some of the evidence for particle acceleration in Earth's magnetosphere during <span class="hlt">substorms</span>. Such in-situ observations in this most accessible of all cosmic plasma domains may hold important clues to understanding acceleration processes in more distant astrophysical systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996ISAA....2.....K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996ISAA....2.....K"><span>Convection and <span class="hlt">Substorms</span> - Paradigms of Magnetospheric Phenomenology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kennel, Charles F.</p> <p></p> <p>The magnetosphere is the region where cosmic rays and the solar wind interact with the Earth's magnetic field, creating such phenomena as the northern lights and other aurorae. The configuration and dynamics of the magnetosphere are of interest to planetary physicists, geophysicists, plasma astrophysicists, and to scientists planning space missions. The circulation of solar wind plasma in the magnetosphere and <span class="hlt">substorms</span> have long been used as the principle paradigms for studying this vital region. Charles F. Kennel, a leading scientist in the field, here presents a synthesis of the convection and <span class="hlt">substorm</span> literatures, and an analysis of convection and <span class="hlt">substorm</span> interactions; he also suggests that the currently accepted steady reconnection model may be advantageously replaced by a model of multiple tail reconnection events, in which many mutually interdependent reconnections occur. Written in an accessible, non-mathematical style, this book introduces the reader to the exciting discoveries in this fast-growing field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950035956&hterms=Ramon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DRamon%2BA.','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950035956&hterms=Ramon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DRamon%2BA."><span>Evidence for particle acceleration during magnetospheric <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lopez, Ramon E.; Baker, Daniel N.</p> <p>1994-01-01</p> <p>Magnetospheric <span class="hlt">substorms</span> represent the episodic dissipation of energy stored in the geomagnetic tail that was previously extracted from the solar wind. This energy release produces activity throughout the entire magnetosphere-ionosphere system, and it results in a wide variety of phenomena such as auroral intensifications and the generation of new current systems. All of these phenomena involve the acceleration of particles, sometimes up to several MeV. We present a brief overview of <span class="hlt">substorm</span> phenomenology. We then review some of the evidence for particle acceleration in Earth's magnetosphere during <span class="hlt">substorms</span>. Such in-situ observations in this most accessible of all cosmic plasma domains may hold important clues to understanding acceleration processes in more distant astrophysical systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JGRA..115.7222N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JGRA..115.7222N"><span><span class="hlt">Substorm</span> triggering by new plasma intrusion: THEMIS all-sky imager observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nishimura, Y.; Lyons, L.; Zou, S.; Angelopoulos, V.; Mende, S.</p> <p>2010-07-01</p> <p>A critical, long-standing problem in <span class="hlt">substorm</span> research is identification of the sequence of events leading to <span class="hlt">substorm</span> auroral onset. Based on event and statistical analysis of THEMIS all-sky imager data, we show that there is a distinct and repeatable sequence of events leading to onset, the sequence having similarities to and important differences from previous ideas. The sequence is initiated by a poleward boundary intensification (PBI) and followed by a north-south (N-S) arc moving equatorward toward the onset latitude. Because of the linkage of fast magnetotail flows to PBIs and to N-S auroras, the results indicate that onset is preceded by enhanced earthward plasma flows associated with enhanced reconnection near the pre-existing open-closed field line boundary. The flows carry new plasma from the open field line region to the plasma sheet. The auroral observations indicate that Earthward-transport of the new plasma leads to a near-Earth instability and auroral breakup ˜5.5 min after PBI formation. Our observations also indicate the importance of region 2 magnetosphere-ionosphere electrodynamic coupling, which may play an important role in the motion of pre-onset auroral forms and determining the local times of onsets. Furthermore, we find motion of the pre-onset auroral forms around the Harang reversal and along the <span class="hlt">growth</span> <span class="hlt">phase</span> arc, reflecting a well-developed region 2 current system within the duskside convection cell, and also a high probability of diffuse-appearing aurora occurrence near the onset latitude, indicating high plasma pressure along these inner plasma sheet field lines, which would drive large region 2 currents.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19740029898&hterms=Hardening&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DHardening','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19740029898&hterms=Hardening&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DHardening"><span><span class="hlt">Substorm</span> effects in auroral spectra. [electron spectrum hardening</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Eather, R. H.; Mende, S. B.</p> <p>1973-01-01</p> <p>A <span class="hlt">substorm</span> time parameter is defined and used to order a large body of photometric data obtained on aircraft expeditions at high latitudes. The statistical analysis demonstrates hardening of the electron spectrum at the time of <span class="hlt">substorm</span>, and it is consistent with the accepted picture of poleward expansion of aurora at the time of <span class="hlt">substorm</span> and curvature drift of <span class="hlt">substorm</span>-injected electrons. These features are not evident from a similar analysis in terms of magnetic time. We conclude that the <span class="hlt">substorm</span> time concept is a useful ordering parameter for auroral data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002EGSGA..27.6237K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002EGSGA..27.6237K"><span>The Bursts Series of Long-period Irregular Ipcl-type Geomagnetic Pulsations As A Element of <span class="hlt">Substorm</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kurazhkovskaya, N. A.; Klain, B. I.</p> <p></p> <p>The investigation of simultaneous observations of bursts series of pulsations ipcl in a frequency band 2.1-5.5 mHz during moderate geomagnetic activity (Kp ~ 2-3), ob- served in the dayside polar cusp and of long-period irregular pulsations apparent in a nightside of an auroral oval was carried out. For the analysis the records of a magnetic field in observatories Mirny (invariant geomagnetic latitude -76,93; longitude 122,92) and Yellownife (invariant geomagnetic latitude 69,94; longitude 294,38), located ap- proximately on one meridian noon - midnight, were used. It was revealed, that regime burst of pulsations ipcl is observed on a <span class="hlt">substorm</span> <span class="hlt">phase</span> recovery. The beginning of bursts series of pulsations ipcl on the dayside of a magnetosphere corresponds to the moment of a final stage of <span class="hlt">substorm</span> expansion <span class="hlt">phase</span> in night sector. Besides regime burst ipcl begins in 60 minutes after change of a direction vertical component IMF with southward on northward. In dominant number of cases the excitation beginning of bursts series of pulsations ipcl lags from a oscillation beginning of pulsations of a type Pi3, accompanying development <span class="hlt">substorms</span>, on 40-60 of minutes. Thus, the anal- ysed bursts series of pulsations ipcl are an essential element of <span class="hlt">substorm</span>. The delay of bursts series ipcl in relation to time of pulsations Pi3-type occurrence and <span class="hlt">substorm</span> expansion <span class="hlt">phase</span> can be explained within the framework of magnetospheric <span class="hlt">substorm</span> model, in which the current across a tail is made through plasma mantle of a magneto- sphere, which field lines are project in dayside polar cusp and entry layes. The release of energy in a tail of magnetosphere in a <span class="hlt">substorm</span> <span class="hlt">phase</span> recovery subsequently leads to intensification of long-period perturbations in dayside polar cusp.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950011840&hterms=john+pedersen&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Djohn%2Bpedersen','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950011840&hterms=john+pedersen&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Djohn%2Bpedersen"><span>Fast ionospheric feedback instability and <span class="hlt">substorm</span> onset</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lysak, Robert L.; Grieger, John; Song, Yan</p> <p>1992-01-01</p> <p>A study suggesting that the Alfven resonator can play an important role in modifying the ionosphere on the time and space scales required to play a significant role in <span class="hlt">substorm</span> formation is presented. Although the effect of magnetosphere-ionosphere coupling on the onset of <span class="hlt">substorms</span> has been studied, the effects due to gradients of the Alfven speed along auroral field line were neglected. The large increase of the Alfven speed with altitude above the ionosphere creates an effective resonant cavity, which can lead to fluctuations in the electric and magnetic fields as well as in particle fluxes in the range 0.1 to 1 Hz. Such fluctuations can be observed from the ground as PiB pulsations associated with <span class="hlt">substorm</span> onset. These fluctuations can be excited by a fast feedback instability, which can grow on time scales much less than the Alfven travel time between the ionosphere and the plasma sheet. The instability enhances the value of both the Pedersen and Hall conductivity, and may play a role in preparing the ionosphere for <span class="hlt">substorm</span> onset.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950011840&hterms=PIB&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DPIB','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950011840&hterms=PIB&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DPIB"><span>Fast ionospheric feedback instability and <span class="hlt">substorm</span> onset</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lysak, Robert L.; Grieger, John; Song, Yan</p> <p>1992-01-01</p> <p>A study suggesting that the Alfven resonator can play an important role in modifying the ionosphere on the time and space scales required to play a significant role in <span class="hlt">substorm</span> formation is presented. Although the effect of magnetosphere-ionosphere coupling on the onset of <span class="hlt">substorms</span> has been studied, the effects due to gradients of the Alfven speed along auroral field line were neglected. The large increase of the Alfven speed with altitude above the ionosphere creates an effective resonant cavity, which can lead to fluctuations in the electric and magnetic fields as well as in particle fluxes in the range 0.1 to 1 Hz. Such fluctuations can be observed from the ground as PiB pulsations associated with <span class="hlt">substorm</span> onset. These fluctuations can be excited by a fast feedback instability, which can grow on time scales much less than the Alfven travel time between the ionosphere and the plasma sheet. The instability enhances the value of both the Pedersen and Hall conductivity, and may play a role in preparing the ionosphere for <span class="hlt">substorm</span> onset.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JGRA..118.6254N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JGRA..118.6254N"><span>Space climate implications from <span class="hlt">substorm</span> frequency</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Newell, P. T.; Gjerloev, J. W.; Mitchell, E. J.</p> <p>2013-10-01</p> <p>solar wind impacting the Earth varies over a wide range of time scales, driving a corresponding range of geomagnetic activity. Past work has strongly indicated that the rate of merging on the frontside magnetosphere is the most important predictor for magnetospheric activity, especially over a few hours. However, the magnetosphere exhibits variations on other time scales, including UT, seasonal, and solar cycle variations. Much of this geomagnetic variation cannot be reasonably attributed to changes in the solar wind driving—that is, it is not created by the original Russell-McPherron effect or any generalization thereof. In this paper we examine the solar cycle, seasonal, and diurnal effects based upon the frequency of <span class="hlt">substorm</span> onsets, using a data set of 53,000 <span class="hlt">substorm</span> onsets. These were identified through the SuperMAG collaboration and span three decades with continuous coverage. Solar cycle variations include a profound minimum in 2009 (448 <span class="hlt">substorms</span>) and peak in 2003 (3727). The magnitude of this variation (a factor of 8.3) is not explained through variations in estimators of the frontside merging rate (such as dΦMP/dt), even when the more detailed probability distribution functions are examined. Instead, v, or better, n1/2v2 seems to be implicated in the dramatic difference between active and quiet years, even beyond the role of velocity in modulating merging. Moreover, we find that although most <span class="hlt">substorms</span> are preceded by flux loading (78.5% are above the mean and 83.8% above median solar wind driving), a high solar wind v is almost as important (68.3% above mean, 74.8% above median). This and other evidence suggest that either v or n1/2v2 (but probably not p) plays a strong secondary role in <span class="hlt">substorm</span> onset. As for the seasonal and diurnal effects, the elliptical nature of the Earth's orbit, which is closest to the Sun in January, leads to a larger solar wind driving (measured by Bs, vBs, or dΦMP/dt) in November, as is confirmed by 22 years of solar wind</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRA..119.2978P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRA..119.2978P"><span><span class="hlt">Substorm</span> occurrence during quiet solar wind driving</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pulkkinen, T. I.; Partamies, N.; Kilpua, E. K. J.</p> <p>2014-04-01</p> <p>We examine the OMNI database and International Monitor for Auroral Geomagnetic Effects (IMAGE) magnetometer chain records to study the <span class="hlt">substorm</span> occurrence and characteristics during quiet solar driving periods, especially during the solar minimum period in 2009. We define <span class="hlt">substorm</span>-like activations as periods where the hourly average AL is below -200 nT. Using the OMNI data set, we demonstrate that there are limiting solar wind speed, interplanetary magnetic field magnitude, and driving electric field values below which <span class="hlt">substorm</span>-like activations (AL < 200 nT, intensification and decay of the electrojet) do not occur. These minimum parameter values are V < 266 km/s, B < 1.4 nT, and E < 0.025 mV/m such low values are observed less than 1% of the time. We also show that for the same level of driving solar wind electric field, the electrojet intensity is smaller (by few tens of nT), and the electrojet resides farther poleward (by over 1°) during extended quiet solar driving in 2009 than during average solar activity conditions. During the solar minimum period in 2009, we demonstrate that <span class="hlt">substorm</span>-like activations can be identified from the IMAGE magnetometer chain observations during periods when the hourly average IL index is below -100 nT. When the hourly IL activity is smaller than that, which covers 87% of the nighttime observations, the electrojet does not show coherent behavior. We thus conclude that <span class="hlt">substorm</span> recurrence time during very quiet solar wind driving conditions is about 5-8 h, which is almost double that of the average solar activity conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920041911&hterms=central+heating&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dcentral%2Bheating','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920041911&hterms=central+heating&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dcentral%2Bheating"><span>Nonadiabatic heating of the central plasma sheet at <span class="hlt">substorm</span> onset</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Huang, C. Y.; Frank, L. A.; Rostoker, G.; Fennell, J.; Mitchell, D. G.</p> <p>1992-01-01</p> <p>Heating events in the plasma sheet boundary layer and central plasma sheet are found to occur at the onset of expansive <span class="hlt">phase</span> activity. The main effect is a dramatic increase in plasma temperature, coincident with a partial dipolarization of the magnetic field. Fluxes of energetic particles increase without dispersion during these events which occur at all radial distances up to 23 RE, the apogee of the ISEE spacecraft. A major difference between these heating events and those observed at geosynchronous distances lies in the heating mechanism which is nonadiabatic beyond 10 RE but may be adiabatic closer to earth. The energy required to account for the increase in plasma thermal energy is comparable with that required for Joule heating of the ionosphere. The plasma sheet must be considered as a major sink in the energy balance of a <span class="hlt">substorm</span>. Lobe magnetic pressures during these events are estimated. Change in lobe pressure are generally not correlated with onsets or intensifications of expansive <span class="hlt">phase</span> activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920045476&hterms=disruption&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Ddisruption','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920045476&hterms=disruption&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Ddisruption"><span>Radial expansion of the tail current disruption during <span class="hlt">substorms</span> - A new approach to the <span class="hlt">substorm</span> onset region</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.; Russell, C. T.</p> <p>1992-01-01</p> <p>A new method is used to examine the radial expansion of the tail current disruption and the <span class="hlt">substorm</span> onset region. The expansion of the disruption region is specified by examining the time sequence (<span class="hlt">phase</span> relationship) between the north-south component and the sun-earth component. This method is tested by applying it to the March 6, 1979, event. The <span class="hlt">phase</span> relationship indicates that the current disruption started on the earthward side of the spacecraft, and expanded tailward past the spacecraft. The method was used for 13 events selected from the ISEE magnetometer data. The results indicate that the current disruption usually starts in the near-earth magnetotail and often within 15 RE from the earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/118382','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/118382"><span><span class="hlt">Phase</span> transformation and <span class="hlt">growth</span> of hygroscopic aerosols</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tang, I.N.</p> <p>1995-09-01</p> <p>Ambient aerosols frequently contain large portions of hygroscopic inorganic salts such as chlorides, nitrates, and sulfates in either pure or mixed forms. Such inorganic salt aerosols exhibit the properties of deliquescence and efflorescence in air. The <span class="hlt">phase</span> transformation from a solid particle to a saline droplet usually occurs spontaneously when the relative humidity of the atmosphere reaches a level specific to the chemical composition of the aerosol particle. Conversely, when the relative humidity decreases and becomes low enough, the saline droplet will evaporate and suddenly crystallize, expelling all its water content. The <span class="hlt">phase</span> transformation and <span class="hlt">growth</span> of aerosols play an important role in many atmospheric processes affecting air quality, visibility degradation, and climate changes. In this chapter, an exposition of the underlying thermodynamic principles is given, and recent advances in experimental methods utilizing single-particle levitation are discussed. In addition, pertinent and available thermodynamic data, which are needed for predicting the deliquescence properties of single and multi-component aerosols, are compiled. This chapter is useful to research scientists who are either interested in pursuing further studies of aerosol thermodynamics, or required to model the dynamic behavior of hygroscopic aerosols in a humid environment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.1102T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.1102T"><span>Solar and Interplanetary Causes of Extremely Intense <span class="hlt">Substorms</span> During Superstorms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsurutani, Bruce; Hajra, Rajkumar; Echer, Ezequiel; Gjerloev, Jesper</p> <p>2016-04-01</p> <p>We have begun a study of particularly intense <span class="hlt">substorms</span> that occur during superstorms. We will relate the solar cycle dependences of events, whether they are externally or internally triggered, and their relationship to other factors such as magnetospheric preconditioning. If time permits, we will explore the details of the events and whether they are similar to regular (Akasofu, 1964) <span class="hlt">substorms</span> or not. These intense <span class="hlt">substorms</span> are an important feature of space weather since they may be responsible for power outages.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850041183&hterms=1055&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3D%2526%25231055','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850041183&hterms=1055&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3D%2526%25231055"><span>Suprathermal O(+) and H(+) ion behavior during the March 22, 1979 (CDAW 6), <span class="hlt">substorms</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.; Scholer, M.; Hovestadt, D.; Klecker, B.</p> <p>1985-01-01</p> <p>The present investigation has the objective to report on the behavior of energetic (approximately 130 keV) O(+) ions in the earth's plasma sheet, taking into account observations by the ISEE 1 spacecraft during a magnetically active time interval encompassing two major <span class="hlt">substorms</span> on March 22, 1979. Attention is also given to suprathermal H(+) and He(++) ions. ISEE 1 plasma sheet observations of the proton and alpha particle <span class="hlt">phase</span> space densities as a function of energy per charge during the time interval 0933-1000 UT on March 22, 1979 are considered along with the proton <span class="hlt">phase</span> space density versus energy in the energy interval approximately 10 to 70 keV for the selected time periods 0933-1000 UT (presubstorm) and 1230-1243 UT (recovery <span class="hlt">phase</span>) during the 1055 <span class="hlt">substorm</span> on March 22, 1979. A table listing the proton energy density for presubstorm and recovery periods is also provided.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850041183&hterms=1055&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2526%25231055','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850041183&hterms=1055&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2526%25231055"><span>Suprathermal O(+) and H(+) ion behavior during the March 22, 1979 (CDAW 6), <span class="hlt">substorms</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.; Scholer, M.; Hovestadt, D.; Klecker, B.</p> <p>1985-01-01</p> <p>The present investigation has the objective to report on the behavior of energetic (approximately 130 keV) O(+) ions in the earth's plasma sheet, taking into account observations by the ISEE 1 spacecraft during a magnetically active time interval encompassing two major <span class="hlt">substorms</span> on March 22, 1979. Attention is also given to suprathermal H(+) and He(++) ions. ISEE 1 plasma sheet observations of the proton and alpha particle <span class="hlt">phase</span> space densities as a function of energy per charge during the time interval 0933-1000 UT on March 22, 1979 are considered along with the proton <span class="hlt">phase</span> space density versus energy in the energy interval approximately 10 to 70 keV for the selected time periods 0933-1000 UT (presubstorm) and 1230-1243 UT (recovery <span class="hlt">phase</span>) during the 1055 <span class="hlt">substorm</span> on March 22, 1979. A table listing the proton energy density for presubstorm and recovery periods is also provided.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhDT.......208C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhDT.......208C"><span>Configuration and Generation of <span class="hlt">Substorm</span> Current Wedge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chu, Xiangning</p> <p></p> <p>The <span class="hlt">substorm</span> current wedge (SCW), a core element of <span class="hlt">substorm</span> dynamics coupling the magnetotail to the ionosphere, is crucial in understanding <span class="hlt">substorms</span>. It has been suggested that the field-aligned currents (FACs) in the SCW are caused by either pressure gradients or flow vortices, or both. Our understanding of FAC generations is based predominately on numerical simulations, because it has not been possible to organize spacecraft observations in a coordinate system determined by the SCW. This dissertation develops an empirical inversion model of the current wedge and inverts midlatitude magnetometer data to obtain the parameters of the current wedge for three solar cycles. This database enables statistical data analysis of spacecraft plasma and magnetic field observations relative to the SCW coordinate. In chapter 2, a new midlatitude positive bay (MPB) index is developed and calculated for three solar cycles of data. The MPB index is processed to determine the <span class="hlt">substorm</span> onset time, which is shown to correspond to the auroral breakup onset with at most 1-2 minutes difference. <span class="hlt">Substorm</span> occurrence rate is found to depend on solar wind speed while <span class="hlt">substorm</span> duration is rather constant, suggesting that <span class="hlt">substorm</span> process has an intrinsic pattern independent of external driving. In chapter 3, an SCW inversion technique is developed to determine the strength and locations of the FACs in an SCW. The inversion parameters for FAC strength and location, and ring current strength are validated by comparison with other measurements. In chapter 4, the connection between earthward flows and auroral poleward expansion is examined using improved mapping, obtained from a newly-developed dynamic magnetospheric model by superimposing a standard magnetospheric field model with <span class="hlt">substorm</span> current wedge obtained from the inversion technique. It is shown that the ionospheric projection of flows observed at a fixed point in the equatorial plane map to the bright aurora as it expands poleward</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910030166&hterms=IRM&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DIRM','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910030166&hterms=IRM&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DIRM"><span>Multipoint observations of a small <span class="hlt">substorm</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lopez, R. E.; Anderson, B. J.; Newell, P. T.; Mcentire, R. W.; Luehr, H.</p> <p>1990-01-01</p> <p>Results are presented of multipoint observations of a small <span class="hlt">substorm</span> which occurred at about 0110 UT on April 25, 1985, carried out by AMPTE CCE, AMPTE IRM, DMSP F6, and DMSP F7, as well as by ground auroral stations and midlatitude stations. These data yield information on the latitudinal extent of the polar cap and provide visual identification of <span class="hlt">substorm</span> aurorae, magnetic perturbations produced directly beneath aurorae, and the situ magnetic field. In addition, they provide magnetic-particle observations of the disruption of the cross-tail current sheet and observations concerning the spatial expansion of the current disruption region. Evidence is presented that the current sheet disruption observed by CCE in the neutral sheet was located on field lines which mapped to the westward traveling surge observed directly overhead of the ground station at Syowa.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19830065821&hterms=streaming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dstreaming','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19830065821&hterms=streaming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dstreaming"><span>Observations of ion streaming during <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lui, A. T. Y.; Williams, D. J.; Eastman, T. E.; Frank, L. A.</p> <p>1983-01-01</p> <p>The ion beam phenomenon at the plasma sheet boundary is examined for individually identifiable <span class="hlt">substorms</span>, and the <span class="hlt">substorm</span>-associated particle phenomena are evaluated in terms of the energy-angle distributions of the plasma population and three-dimensional energetic ion distributions. In all seven cases studied it is found that ion beams streaming earthward and/or tailward are always present at the edge of the plasma sheet adjacent to the tail lobe. Ion beams penetrating into the plasma sheet region with no detectable density gradient are also observed. Beams at tens to hundreds of eV often stream tailward and are often long lasting, suggesting that they may be related to ionospheric sources. Both tailward and earthward streaming beams are detected for ion beams above 1 keV, consistent with an origin from the distant tail, propagation toward earth, and mirroring back under single particle motions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910030166&hterms=observation+identification&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dobservation%2Bidentification','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910030166&hterms=observation+identification&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dobservation%2Bidentification"><span>Multipoint observations of a small <span class="hlt">substorm</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lopez, R. E.; Anderson, B. J.; Newell, P. T.; Mcentire, R. W.; Luehr, H.</p> <p>1990-01-01</p> <p>Results are presented of multipoint observations of a small <span class="hlt">substorm</span> which occurred at about 0110 UT on April 25, 1985, carried out by AMPTE CCE, AMPTE IRM, DMSP F6, and DMSP F7, as well as by ground auroral stations and midlatitude stations. These data yield information on the latitudinal extent of the polar cap and provide visual identification of <span class="hlt">substorm</span> aurorae, magnetic perturbations produced directly beneath aurorae, and the situ magnetic field. In addition, they provide magnetic-particle observations of the disruption of the cross-tail current sheet and observations concerning the spatial expansion of the current disruption region. Evidence is presented that the current sheet disruption observed by CCE in the neutral sheet was located on field lines which mapped to the westward traveling surge observed directly overhead of the ground station at Syowa.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940010960','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940010960"><span>Formation of the stable auroral arc that intensifies at <span class="hlt">substorm</span> onset</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lyons, L. R.; Samson, J. C.</p> <p>1993-01-01</p> <p>In a companion paper, we present observational evidence that the stable, <span class="hlt">growth-phase</span> auroral arc that intensifies at <span class="hlt">substorm</span> expansion <span class="hlt">phase</span> onset often forms on magnetic field lines that map to within approximately 1 to 2 R(sub e) of synchronous. The equatorial plasma pressure is 1 to 10 nPa in this region, which can give a cross-tail current greater than 0.1 A/m. In this paper, we propose that the arc is formed by a perpendicular magnetospheric-current divergence that results from a strong dawn-to-dusk directed pressure gradient in the vicinity of magnetic midnight. We estimate that the current divergence is sufficiently strong that a is greater than 1 kV field-aligned potential drop is required to maintain ionospheric-current continuity. We suggest that the azimuthal pressure gradient results from proton drifts in the vicinity of synchronous orbit that are directed nearly parallel to the cross-tail electric field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JGRA..115.7205S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JGRA..115.7205S"><span>Ionospheric feedback instability and <span class="hlt">substorm</span> development</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Streltsov, A. V.; Pedersen, T. R.; Mishin, E. V.; Snyder, A. L.</p> <p>2010-07-01</p> <p>We report on ground magnetic and optical observations performed during an ionospheric heating experiment at the High Frequency Active Auroral Research Program (HAARP) facility in Alaska on 29 October 2008. The experiment was aimed at generation of large-amplitude ULF electromagnetic waves by triggering and facilitating development of the ionospheric feedback instability (IFI) in the region adjacent to a bright auroral arc. In this region the downward/return magnetic field-aligned current decreases plasma density and enhances the electric field in the ionosphere. A combination of these two effects creates favorable conditions for the instability. The experiment occurred during a period of <span class="hlt">substorm</span> activity, but effects from the HAARP transmitter were not sufficiently intense to be detected against the background of strong natural oscillations occurring farther north from the HAARP site. Thus the experiment did not provide concrete evidence that heating of the ionosphere with powerful HF transmitters can affect IFI development or generate intense ULF electromagnetic waves. However, during the experiment ground-based magnetometers in Alaska and Canada detected large-amplitude ULF waves in regions where the <span class="hlt">substorm</span> onset auroral arcs interacted with the ionosphere. The frequencies of these waves closely matched frequencies predicted by simulations of IFI for these particular geophysical conditions. These observations support the hypothesis that geomagnetic <span class="hlt">substorms</span>, the corresponding dynamics of discrete auroral arcs, and the ionospheric feedback instability are closely connected phenomena.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19880033112&hterms=Edmonton&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DEdmonton','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19880033112&hterms=Edmonton&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DEdmonton"><span>A boundary layer model for magnetospheric <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rostoker, Gordon; Eastman, Tim</p> <p>1987-01-01</p> <p>An alternative framework for understanding magnetospheric <span class="hlt">substorm</span> activity is presented. It is argued that observations of magnetic field and plasma flow variations in the magnetotail can be explained in terms of the passage of the plasma sheet boundary layer over the satellite detecting the tail signatures. It is shown that field-aligned currents and particle acceleration processes on magnetic field lines threading the ionospheric Harang discontinuity lead to the distinctive particle and field signatures observed in the magnetotail during <span class="hlt">substorms</span>. It is demonstrated that edge effects of field-aligned currents associated with the westward traveling surge can lead to the negative B(z) perturbations observed in the tail that are presently attributed to observations made on the anti-earthward side of a near-earth neutral line. Finally, it is shown that the model can provide a physical explanation of both the driven system and the loading-unloading system whose combined effects provide the observed <span class="hlt">substorm</span> perturbation pattern in the magnetosphere and ionosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820026628&hterms=Radiation+Belts&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DRadiation%2BBelts','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820026628&hterms=Radiation+Belts&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DRadiation%2BBelts"><span>Dynamics of the outer radiation belts in relation to polar <span class="hlt">substorms</span> and hot plasma injections at geostationary altitude</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sauvaud, J. A.; Winckler, J. R.</p> <p>1981-01-01</p> <p>Geostationary satellite and ground measurements of dynamic variations of the outer radiation belts and their relations with the development of auroral structures during magnetospheric <span class="hlt">substorms</span> are analyzed. A comparison of measurements of the H or X geomagnetic field components made by seven auroral stations with ATS-6 low-energy and high-energy particle measurements during the multiple-onset <span class="hlt">substorm</span> of Aug. 16, 1974 is presented which demonstrates that while the decrease in energetic particle fluxed ends only at the time of a strong <span class="hlt">substorm</span> onset, rapid motions of the outer radiation belts may occur during the flux decrease. All-sky photographs of auroral phenomena taken at Fort Yukon and College, Alaska are then compared with ATS-1 energetic particle flux measurements in order to demonstrate the relation between flux decreases and increases and distinct <span class="hlt">substorm</span> <span class="hlt">phases</span>. Results support the hypothesis of a magnetospheric <span class="hlt">substorm</span> precursor which appears to be an instability growing at the inner boundary of the plasma layer and approaching the earth, and underline the importance of current and magnetic field variations in charged particle dynamics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5806189','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5806189"><span>Dynamics of the 1054 UT March 22, 1979, <span class="hlt">substorm</span> event: CDAW 6</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>McPherron, R.L.; Manka, R.H.</p> <p>1985-02-01</p> <p>The physical processes involved in the transfer of energy from the solar wind to the magnetosphere, and release associated with <span class="hlt">substorms</span>, have been examined in a sequence of Coordinated Data Analysis Workshops (CDAW 6). Magnetic storms of March 22 and 31, 1979, were chosen to study the problem, using a data base from 13 spacecraft and about 130 ground-based magnetometers. This paper describes the March 22 storm, in particular the large, isolated <span class="hlt">substorm</span> at 1054 UT which followed an interval of magnetic calm. We summarize the observations in the solar wind, in various regions of the magnetosphre, and at the ground, synthesizing these observations into a description of the substorn development. We then give our interpretation of these observations and test their consistency with the reconnection model. The <span class="hlt">substorm</span> appears to have been generated by a southward turning of the interplanetary magnetic field associated with a current sheet crossing. Models of ionospheric currents derived from ground data show the <span class="hlt">substorm</span> had three <span class="hlt">phases</span> of development. During the first <span class="hlt">phase</span>, a two-celled convection current system developed in the polar cap as synchronous spacecraft on the nightside recorded an increasingly tailike field and the ISEE measurements show that the near-earth plasma sheet thinned. In the second <span class="hlt">phase</span>, possibly triggered by sudden changes in the solar wind, a one-celled current system was added to the first, enhancing the westward electrojet. During this <span class="hlt">phase</span> the synchronous orbit field became more dipolar, and the plasma sheet magnetic field turned strongly southward as rapid tailward flow developed soon after expansion onset, suggesting that a neutral line formed in the near-earth plasma sheet with subsequent plasmoid ejection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6371273','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6371273"><span>Energy storage and dissipation in the magnetotail during <span class="hlt">substorms</span>. 2. MHD simulations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Steinolfson, R.S. ); Winglee, R.M. )</p> <p>1993-05-01</p> <p>The authors present a global MHD simulation of the magnetotail in an effort to study magnetic storm development. They address the question of energy storage in the current sheet in the early <span class="hlt">phases</span> of storm <span class="hlt">growth</span>, which previous simulations have not shown. They address this problem by dealing with the variation of the resistivity throughout the magnetosphere. They argue that MHD theory should provide a suitable representation to this problem on a global scale, even if it does not handle all details adequately. For their simulation they use three different forms for the resistivity. First is a uniform and constant resistivity. Second is a resistivity proportional to the current density, which is related to argument that resistivity is driven by wave-particle interactions which should be strongest in regions where the current is the greatest. Thirdly is a model where the resistivity varies with the magnetic field strength, which was suggested by previous results from particle simulations of the same problem. The simulation then gives approximately the same response of the magnetosphere for all three of the models. Each results in the formation and ejection of plasmoids, but the energy stored in the magnetotail, the timing of <span class="hlt">substorm</span> onset in relation to the appearance of a southward interplanetary magnetic field, and the speed of ejection of the plasmoids formed differ with the resistivity models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1611994P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1611994P"><span>A multi-instrumental case study of the <span class="hlt">substorm</span> event occurring 2002-09-08</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Palin, Laurianne; Ågren, Karin; zivkovic, Tatjana; Opgenoorth, Hermann; Fasckó, Gabor; Sergeev, Victor; Kubyshkina, Marina; Nikolaev, Alexander; Milan, Steve; Imber, Suzanne; Kauristie, Kirsti; Palmroth, Minna; van de Kamp, Max; Nakamura, Rumi; Boakes, Peter</p> <p>2014-05-01</p> <p>Multi-instrumental data mining and interpretation can be tricky. In this context, the ECLAT (European Cluster Assimilation Technology) project was created to « provide a novel and unique data base and tools for space scientists, by providing an upgrade of the European Space Agency's Cluster Active Archive (CAA). » How can this new tool help the space plasma physics community? Here we demonstrate the power of coordinated global and meso-scale ground-based data to put satellite data into the proper context. We re-analyse a well-isolated <span class="hlt">substorm</span> with a strong <span class="hlt">growth</span> <span class="hlt">phase</span>, which starts right overhead the Scandinavian network of instruments. This event was previously studied in detail by Sergeev et al (2005), based on a THEMIS-like configuration near-midnight using a unique radial constellation of LANL (~6.6Re), Geotail and Polar (~9Re), and Cluster (~16Re). In this new study we add detailed IMAGE spacecraft and ground-based network data. Several magnetospheric models are specially adapted using solar wind conditions and in-situ observations. Simulation results are compared to the in-situ observations and discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMSM31D..01N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMSM31D..01N"><span>Auroral Acceleration, Solar Wind Driving, and <span class="hlt">Substorm</span> Triggering (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Newell, P. T.; Liou, K.</p> <p>2010-12-01</p> <p>We use a data base of 4861 <span class="hlt">substorms</span> identified by global UV images to investigate the <span class="hlt">substorm</span> cycle dependence of various types of aurora, and to obtain new results on <span class="hlt">substorm</span> triggering by external driving. Although all types of aurora increase at <span class="hlt">substorm</span> onset, broadband (Alfvénic) aurora shows a particular association with <span class="hlt">substorms</span>, and, especially, <span class="hlt">substorm</span> onset. While diffuse electron and monoenergetic auroral precipitating power rises by 79% and 90% respectively following an onset, broadband aurora rises by 182%. In the first 10-15 minutes following onset, the power associated with Alfvénic acceleration is comparable to monoenergetic acceleration (also called “inverted-V” events). In general, this is not the case prior to onset, or indeed, during recovery. The rise time of the electron diffuse aurora following onset is much slower, about 50 minutes, and thus presumably extends into recovery. We also re-investigate the issue of solar wind triggering of <span class="hlt">substorms</span> by considering not just changes in the solar wind prior to onset, but how the pattern of changes differs from random and comparable epochs. We verify that a preonset reduction of solar wind driving (“northward turning” in the simplest case of IMF Bz) holds for the superposed epoch mean of the ensemble. Moreover, this reduction is not the result of a small number of <span class="hlt">substorms</span> with large changes. The reduction starts about 20 min prior to <span class="hlt">substorm</span> onset, which, although a longer delay than previously suggested, is appropriate given the various propagation time delays involved. Next, we compare the IMF to random solar wind conditions. Not surprisingly, solar wind driving prior to onset averages somewhat higher than random. Although about a quarter of <span class="hlt">substorms</span> occur for steady northward IMF conditions, more general coupling functions such as the Kan-Lee electric field, the Borovosky function, or our dΦMP/dt, show very few <span class="hlt">substorms</span> occur following weak dayside merging. We assembled a data</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1910754B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1910754B"><span>Common solar wind drivers behind magnetic storm - magnetospheric <span class="hlt">substorm</span> dependency</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Balasis, Georgios; Runge, Jakob; Daglis, Ioannis A.; Papadimitriou, Constantinos; Donner, Reik E.</p> <p>2017-04-01</p> <p>The storm-<span class="hlt">substorm</span> relationship is one of the most controversial aspects of geospace magnetic storm dynamics and one of the unresolved topics of solar-terrestrial coupling. Here we investigate the statistical dependencies between storm and <span class="hlt">substorm</span> indices in conjunction with multiple relevant solar wind variables with an information-theoretic causal inference approach. We find that the vertical component of the interplanetary magnetic field is the strongest driver of both storms and <span class="hlt">substorms</span>. Importantly, this common driver explains the transfer entropy between <span class="hlt">substorms</span> and storms found by a previous bivariate analysis. These results hold during both a year close to solar maximum (2001) and minimum (2008) and suggest that, at least based on the analyzed indices, there is no statistical evidence of a direct or indirect information transfer and, therefore, likely no physical mechanism by which <span class="hlt">substorms</span> drive storms or vice versa.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JASTP.146...28N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JASTP.146...28N"><span><span class="hlt">Substorm</span> probabilities are best predicted from solar wind speed</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Newell, P. T.; Liou, K.; Gjerloev, J. W.; Sotirelis, T.; Wing, S.; Mitchell, E. J.</p> <p>2016-08-01</p> <p>Most measures of magnetospheric activity - including auroral power (AP), magnetotail stretching, and ring current intensity - are best predicted by solar wind-magnetosphere coupling functions which approximate the frontside magnetopause merging rate. However radiation belt fluxes are best predicted by a simpler function, namely the solar wind speed, v. Since most theories of how these high energy electrons arise are associated with repeated rapid dipolarizations such as associated with <span class="hlt">substorms</span>, this apparent discrepancy could be reconciled under the hypothesis that the frequency of <span class="hlt">substorms</span> tracks v rather than the merging rate - despite the necessity of magnetotail flux loading prior to <span class="hlt">substorms</span>. Here we investigate this conjecture about v and <span class="hlt">substorm</span> probability. Specifically, a continuous list of <span class="hlt">substorm</span> onsets compiled from SuperMAG covering January 1, 1997 through December 31, 2007 are studied. The continuity of SuperMAG data and near continuity of solar wind measurements minimize selection bias. In fact v is a much better predictor of onset probability than is the overall merging rate, with <span class="hlt">substorm</span> odds rising sharply with v. Some loading by merging is necessary, and frontside merging does increase <span class="hlt">substorm</span> probability, but nearly as strongly as does v taken alone. Likewise, the effects of dynamic pressure, p, are smaller than simply v taken by itself. Changes in the solar wind matter, albeit modestly. For a given level of v (or Bz), a change in v (or Bz) will increase the odds of a <span class="hlt">substorm</span> for at least 2 h following the change. A decrease in driving elevates <span class="hlt">substorm</span> probabilities to a greater extent than does an increase, partially supporting external triggering. Yet current v is the best single predictor of subsequently observing a <span class="hlt">substorm</span>. These results explain why geomagnetically quiet years and active years are better characterized by low or high v (respectively) than by the distribution of merging estimators. It appears that the flow of energy</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EOSTr..91..269A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EOSTr..91..269A"><span>Auroral <span class="hlt">Substorms</span>: Paradigm Shifts in Research</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Akasofu, Syun-Ichi</p> <p>2010-08-01</p> <p>The study of scientific advancement is the study of evolving thought. Disciplines progress as old prevailing theoretical ideas are toppled by new ones, one after another. Provided that new ideas can be independently verified, scientists at any level can greatly contribute to their field. Though space weather is a young field, it has been riddled with such paradigm shifts. As a scientist who has worked on auroral and magnetospheric <span class="hlt">substorm</span> research during several of these moments, I have witnessed firsthand how diligence, patience, and creativity combine to advance science.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19970016584&hterms=observation+spatiale&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dobservation%2Bspatiale','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19970016584&hterms=observation+spatiale&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dobservation%2Bspatiale"><span>Interball <span class="hlt">substorm</span> observations: Christmas for space scientists</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sandahl, Ingrid; Pulkkinen, Tuija; Budnik, Elena Yu.; Dubinin, Edouard M.; Eklund, Ulrik; Hughes, Terence J.; Kokubun, Susumu; Koskinen, Hannu; Kudela, Karel; Lepping, Ronald P.; Lin, Robert P.; Lui, Anthony T. Y.; Lutsenko, Volt; Mostroem, Arne; Nozdrachev, Michail; Pissarenko, Novomir, F.; Prokhorenko, Victoria; Sauvaud, Jean-Andre; Yermolaev, Yuri I.; Zakharov, Alexander V.</p> <p>1996-01-01</p> <p>Observational results from the Interball Tail Probe spacecraft are presented. One of the main objectives of the Interball project is to study the dynamic processes in the magnetosphere. Three events observed by the spacecraft's instruments are investigated: a pseudobreakup during which earthward streaming ions were observed in the vicinity of a thin current sheet; a <span class="hlt">substorm</span> in which the magnetic signatures in the lobe and on the ground were preceeded by northward re-orientation of the interplanetary magnetic field Bz component; and a magnetic storm at the beginning of which extreme deformation of the magnetotail was observed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19970016584&hterms=scientist&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dscientist','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19970016584&hterms=scientist&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dscientist"><span>Interball <span class="hlt">substorm</span> observations: Christmas for space scientists</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sandahl, Ingrid; Pulkkinen, Tuija; Budnik, Elena Yu.; Dubinin, Edouard M.; Eklund, Ulrik; Hughes, Terence J.; Kokubun, Susumu; Koskinen, Hannu; Kudela, Karel; Lepping, Ronald P.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_19970016584'); toggleEditAbsImage('author_19970016584_show'); toggleEditAbsImage('author_19970016584_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_19970016584_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_19970016584_hide"></p> <p>1996-01-01</p> <p>Observational results from the Interball Tail Probe spacecraft are presented. One of the main objectives of the Interball project is to study the dynamic processes in the magnetosphere. Three events observed by the spacecraft's instruments are investigated: a pseudobreakup during which earthward streaming ions were observed in the vicinity of a thin current sheet; a <span class="hlt">substorm</span> in which the magnetic signatures in the lobe and on the ground were preceeded by northward re-orientation of the interplanetary magnetic field Bz component; and a magnetic storm at the beginning of which extreme deformation of the magnetotail was observed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM31F..01M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM31F..01M"><span>The Four-Part Field-Aligned Current System in the Ionosphere at <span class="hlt">Substorm</span> Onset</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McWilliams, K. A.; Sofko, G. J.; Bristow, W. A.; Hussey, G. C.</p> <p>2015-12-01</p> <p> lines in the convection pattern have a strong vorticity near the convection reversal. By Faraday's Law of Induction there is a decrease in magnetic flux density on the poleward side of the convection reversal, and an increase on the equatorward side. We address this issue for two different time intervals, namely the late <span class="hlt">growth</span> <span class="hlt">phase</span> and then the <span class="hlt">substorm</span> onset.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20080032584&hterms=evolution+bats&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Devolution%2Bbats','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20080032584&hterms=evolution+bats&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Devolution%2Bbats"><span>Magnetotail Current Sheet Thinning and Magnetic Reconnection Dynamics in Global Modeling of <span class="hlt">Substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kuznetsova, M. M.; Hesse, M.; Rastaetter, L.; Toth, G.; DeZeeuw, D. L.; Gombosi, T. I.</p> <p>2008-01-01</p> <p>Magnetotail current sheet thinning and magnetic reconnection are key elements of magnetospheric <span class="hlt">substorms</span>. We utilized the global MHD model BATS-R-US with Adaptive Mesh Refinement developed at the University of Michigan to investigate the formation and dynamic evolution of the magnetotail thin current sheet. The BATSRUS adaptive grid structure allows resolving magnetotail regions with increased current density up to ion kinetic scales. We investigated dynamics of magnetotail current sheet thinning in response to southwards IMF turning. Gradual slow current sheet thinning during the early <span class="hlt">growth</span> <span class="hlt">phase</span> become exponentially fast during the last few minutes prior to nightside reconnection onset. The later stage of current sheet thinning is accompanied by earthward flows and rapid suppression of normal magnetic field component $B-z$. Current sheet thinning set the stage for near-earth magnetic reconnection. In collisionless magnetospheric plasma, the primary mechanism controlling the dissipation in the vicinity of the reconnection site is non-gyrotropic effects with spatial scales comparable with the particle Larmor radius. One of the major challenges in global MHD modeling of the magnetotail magnetic reconnection is to reproduce fast reconnection rates typically observed in smallscale kinetic simulations. Bursts of fast reconnection cause fast magnetic field reconfiguration typical for magnetospheric <span class="hlt">substorms</span>. To incorporate nongyritropic effects in diffusion regions we developed an algorithm to search for magnetotail reconnection sites, specifically where the magnetic field components perpendicular to the local current direction approaches zero and form an X-type configuration. Spatial scales of the diffusion region and magnitude of the reconnection electric field are calculated self-consistently using MHD plasma and field parameters in the vicinity of the reconnection site. The location of the reconnection sites and spatial scales of the diffusion region are updated</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990098449&hterms=Analysis+interaction+network&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DAnalysis%2Binteraction%2Bnetwork','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990098449&hterms=Analysis+interaction+network&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DAnalysis%2Binteraction%2Bnetwork"><span>Analysis of Auroral Morphology: <span class="hlt">Substorm</span> Precursor and Onset on January 10, 1997</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Germany, G. A.; Parks, G. K.; Ranganath, H.; Elsen, R.; Richards, P. G.; Swift, W.; Spann, J. F., Jr.; Brittnacher, M. J.</p> <p>1998-01-01</p> <p>The solar wind interaction with the geomagnetic field is studied using global auroral images obtained by the Ultraviolet Imager (UVI) on Polar. We study the dynam,cs of the poleward and equatorward boundaries of the auroral oval in response to the solar wind IMF on January 10, 1997 using a neural network algorithm to perform an automated morphological analysis. Poleward and equatorward boundaries identified by the algorithm demonstrate a clear <span class="hlt">growth</span> motion with the southward turning of the IMF and <span class="hlt">growth</span> and poleward expansion at <span class="hlt">substorm</span> onset. The area poleward of the oval (polar cap) is found to increase in size coincident with the'southward turning of the IMF Bz component at 0220 UT and peaks at <span class="hlt">substorm</span> onset at 0334 UT. The area of the oval, however, decreases continuously throughout the period of the polar cap area increase with a slight recovery observed during the <span class="hlt">substorm</span> onset. These observations are consistent with the concept that magnetospheric dynamics are directly driven by the solar wind-geomagnetic field interactions.</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://hdl.handle.net/2060/20020050515','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020050515"><span>Energetic Electron Populations in the Magnetosphere During Geomagnetic Storms and <span class="hlt">Substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>McKenzie, David L.; Anderson, Phillip C.</p> <p>2002-01-01</p> <p>This report summarizes the scientific work performed by the Aerospace Corporation under NASA Grant NAG5-10278, 'Energetic Electron Populations in the Magnetosphere during Geomagnetic Storms and Subsisting.' The period of performance for the Grant was March 1, 2001 to February 28, 2002. The following is a summary of the Statement of Work for this Grant. Use data from the PIXIE instrument on the Polar spacecraft from September 1998 onward to derive the statistical relationship between particle precipitation patterns and various geomagnetic activity indices. We are particularly interested in the occurrence of <span class="hlt">substorms</span> during storm main <span class="hlt">phase</span> and the efficacy of storms and <span class="hlt">substorms</span> in injecting ring-current particles. We will compare stormtime simulations of the diffuse aurora using the models of Chen and Schulz with stormtime PIXIE measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22351133','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22351133"><span>Nitrogen controlled iron catalyst <span class="hlt">phase</span> during carbon nanotube <span class="hlt">growth</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bayer, Bernhard C.; Baehtz, Carsten; Kidambi, Piran R.; Weatherup, Robert S.; Caneva, Sabina; Cabrero-Vilatela, Andrea; Hofmann, Stephan; Mangler, Clemens; Kotakoski, Jani; Meyer, Jannik C.; Goddard, Caroline J. L.</p> <p>2014-10-06</p> <p>Close control over the active catalyst <span class="hlt">phase</span> and hence carbon nanotube structure remains challenging in catalytic chemical vapor deposition since multiple competing active catalyst <span class="hlt">phases</span> typically co-exist under realistic synthesis conditions. Here, using in-situ X-ray diffractometry, we show that the <span class="hlt">phase</span> of supported iron catalyst particles can be reliably controlled via the addition of NH{sub 3} during nanotube synthesis. Unlike polydisperse catalyst <span class="hlt">phase</span> mixtures during H{sub 2} diluted nanotube <span class="hlt">growth</span>, nitrogen addition controllably leads to <span class="hlt">phase</span>-pure γ-Fe during pre-treatment and to <span class="hlt">phase</span>-pure Fe{sub 3}C during <span class="hlt">growth</span>. We rationalize these findings in the context of ternary Fe-C-N <span class="hlt">phase</span> diagram calculations and, thus, highlight the use of pre-treatment- and add-gases as a key parameter towards controlled carbon nanotube <span class="hlt">growth</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19900008209','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19900008209"><span>A current disruption mechanism in the neutral sheet for triggering <span class="hlt">substorm</span> expansions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lui, A. T. Y.; Mankofsky, A.; Chang, C.-L.; Papadopoulos, K.; Wu, C. S.</p> <p>1989-01-01</p> <p>Two main areas were addressed in support of an effort to understand mechanism responsible for the broadband electrostatic noise (BEN) observed in the magnetotail. The first area concerns the generation of BEN in the boundary layer region of the magnetotail whereas the second area concerns the occassional presence of BEN in the neutral sheet region. For the generation of BEN in the boundary layer region, a hybrid simulation code was developed to perform reliable longtime, quiet, highly resolved simulations of field aligned electron and ion beam flow. The result of the simulation shows that broadband emissions cannot be generated by beam-plasma instability if realistic values of the ion beam parameters are used. The waves generated from beam-plasma instability are highly discrete and are of high frequencies. For the plasma sheet boundary layer condition, the wave frequencies are in the kHz range, which is incompatible with the observation that the peak power in BEN occur in the 10's of Hz range. It was found that the BEN characteristics are more consistent with lower hybrid drift instability. For the occasional presence of BEN in the neutral sheet region, a linear analysis of the kinetic cross-field streaming instability appropriate to the neutral sheet condition just prior to onset of <span class="hlt">substorm</span> expansion was performed. By solving numerically the dispersion relation, it was found that the instability has a <span class="hlt">growth</span> time comparable to the onset time scale of <span class="hlt">substorm</span> onset. The excited waves have a mixed polarization in the lower hybrid frequency range. The imposed drift driving the instability corresponds to unmagnetized ions undergoing current sheet acceleration in the presence of a cross-tail electric field. The required electric field strength is in the 10 mV/m range which is well within the observed electric field values detected in the neutral sheet during <span class="hlt">substorms</span>. This finding can potentially account for the disruption of cross-tail current and its diversion to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JASTP.119..129D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JASTP.119..129D"><span>Eastward electrojet enhancements during <span class="hlt">substorm</span> activity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>D'Onofrio, M.; Partamies, N.; Tanskanen, E.</p> <p>2014-11-01</p> <p>In this study, we use a semi-automatic routine to identify negative and positive bays in the IMAGE magnetometer data during seven months in 2003. The IMAGE stations have been divided into three latitude regions to monitor the time evolution and temporal relationship between the regions during <span class="hlt">substorms</span>. In particular, we focus on the events where both positive and negative ground magnetic deflections are observed in different latitude regions. We found 101 events in total. We examine separately a subset of 32 events, for which the local electrojet index values are larger than the global ones, suggesting that the strongest activity at that time takes place within or very close to the local time sector of IMAGE. We systematically analyze the temporal difference and the intensity of the positive and negative bays. Our results show that the magnitude of the positive bay is on average about half of that of the negative bay. Two thirds of the positive bays within the IMAGE network peak earlier than the negative bays. Because the positive and negative bays occur meridionally very close together, we suggest that the enhancements of the westward current at the poleward part of the auroral oval and the eastward current within the return flow are very tightly coupled through field-aligned currents and closing horizontal currents. The <span class="hlt">substorm</span> current system appears as a superposition on the large-scale current pattern in the vicinity of the evening sector shear flow region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20170003503&hterms=hotel&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dhotel','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20170003503&hterms=hotel&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dhotel"><span>Special Issue the 12th International Conference on <span class="hlt">Substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shiokawa, Kazuo; Fok, Mei-Ching; Fujimoto, Masaki</p> <p>2016-01-01</p> <p>The 12th International Conference on <span class="hlt">Substorms</span> (ICS-12) was held at the Ise-Shima Royal Hotel in Shima, Japan, on November 10-14, 2014. There were 125 attendees including 68 from foreign countries. The ICS has been held every 2 years since 1992 to discuss <span class="hlt">substorms</span>, which are fundamental global-scale disturbances in the Earth's magnetosphere. The year 2014 marked the 50th anniversary of the first publication about <span class="hlt">substorms</span> (Akasofu 1964). The conference included three tutorial lecturers (Profs. S.-I. Akasofu, V. Angelopoulous, and D. Baker), as well as many international scientists, to discuss <span class="hlt">substorm</span> processes in the tail, their Interactions with the inner magnetosphere and the ionosphere, <span class="hlt">substorm</span> currents and their dynamics and energetics, the role of MagnetoHydroDynamics (MHD) and kinetic instabilities, storm-<span class="hlt">substorm</span> relationships, ULFELFVLF waves, and non-Earth <span class="hlt">substorm</span>-like features. Prof. Akasofu also gave an evening talk about the history of auroral research since the nineteenth century with photographs that inspired and intrigued the young scientists and students in attendance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMSM43A1699K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMSM43A1699K"><span>Response of high-energy particle precipitation to <span class="hlt">substorm</span> onset</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kellerman, A. C.; Makarevich, R. A.</p> <p>2008-12-01</p> <p>The process of extra-terrestrial radiowave absorption by ionospheric electrons is known as cosmic noise absorption (CNA) and is routinely detected by ground-based relative opacity meters or riometers, which are sensitive to high-energy particle precipitation (>10 keV). In this study, we investigate the response of high- energy particle precipitation to <span class="hlt">substorm</span> onset by employing a 7×7-beam imaging riometer system in Northern Scandinavia, IRIS, and the <span class="hlt">substorm</span> onset database from the IMAGE satellite. The CNA response is investigated with respect to <span class="hlt">substorm</span> location relative to IRIS. Instantaneous responses are mostly observed when IRIS is located on the same magnetic parallel as the <span class="hlt">substorm</span> onset region. We investigate dispersionless injections (DIs) associated with <span class="hlt">substorm</span> onsets as detected by the imaging riometer. It is shown that an auroral absorption signature is present predominantly for DIs located westward of IRIS, which is consistent with high-energy particles propagating eastward from <span class="hlt">substorm</span> injection location. Superposed epoch analysis of CNA relative to <span class="hlt">substorm</span> onset timing shows a strong dependence on the azimuthal sector in which the onset is located relative to IRIS. Rapid responses are observed in 90-135 deg geographic azimuths indicating fast westward and poleward propagation from onset location. Responses to onsets located between -90 to -180 deg show a monotonic decrease in rise time. The results are examined in the context of the geosynchronous LANL and GOES satellite data in order to investigate the two propagation mechanisms: expansion of injection region and particle drift.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM41F2555W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM41F2555W"><span>Geosynchronous Electron Fluxes and Chorus Generation During an MHD <span class="hlt">Substorm</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Woodroffe, J. R.; Jordanova, V.; Henderson, M. G.; Welling, D. T.; Vernon, L.</p> <p>2015-12-01</p> <p>We present results from a numerical study of electron dynamics and whistler generation during an idealized <span class="hlt">substorm</span> simulated using the Space Weather Modeling Framework. The time-dependent electric and magnetic fields from this simulated <span class="hlt">substorm</span> are used to drive a new backwards particle tracing model, and the results from this model are used to identify the regions responsible for populating geosynchronous orbit during and after the <span class="hlt">substorm</span>. Liouville mapping is then used to obtain electron fluxes at geosynchronous orbit as well as to assess the development of anisotropy during the earthward propagation of the electron injection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMSM23D2335B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMSM23D2335B"><span>Dynamics of the AMPERE Region 1 Birkeland current oval during storms, <span class="hlt">substorms</span> and steady magnetospheric convection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baker, J. B.; Clausen, L.; Ruohoniemi, J. M.; Milan, S. E.; Kissinger, J.; Anderson, B. J.; Wing, S.</p> <p>2012-12-01</p> <p>Using radial current densities provided by the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) we employ a fitting scheme to identify the location of the maximum Region 1 field-aligned (Birkeland) current at all magnetic local times. We call this parameter the "R1 oval" and we investigate its behavior during various modes of magnetospheric activity such as storms, <span class="hlt">substorms</span> and steady magnetospheric convection (SMCs). Results show the following: (1) during <span class="hlt">substorms</span> the radius of the R1 oval undergoes a cyclic inflation and contraction which matches the standard paradigm for <span class="hlt">substorm</span> <span class="hlt">growth</span> (loading) and expansion (unloading); (2) during SMCs the R1 oval is relatively steady consistent with balanced dayside and nightside reconnection during these events; and (3) during magnetic storms the size of the R1 oval is strongly correlated with the strength of the ring current specified by the Sym-H index. We also examine the behavior of the R1 oval in the northern and southern hemispheres simultaneously as a function of season in an effort to understand the role that internal magnetosphere-ionosphere coupling influences may play in modulating the response of the magnetosphere during these various types of events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005PhRvE..72a1602F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005PhRvE..72a1602F"><span>Quantitative <span class="hlt">phase</span>-field modeling of two-<span class="hlt">phase</span> <span class="hlt">growth</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Folch, R.; Plapp, M.</p> <p>2005-07-01</p> <p>A <span class="hlt">phase</span>-field model that allows for quantitative simulations of low-speed eutectic and peritectic solidification under typical experimental conditions is developed. Its cornerstone is a smooth free-energy functional, specifically designed so that the stable solutions that connect any two <span class="hlt">phases</span> are completely free of the third <span class="hlt">phase</span>. For the simplest choice for this functional, the equations of motion for each of the two solid-liquid interfaces can be mapped to the standard <span class="hlt">phase</span>-field model of single-<span class="hlt">phase</span> solidification with its quartic double-well potential. By applying the thin-interface asymptotics and by extending the antitrapping current previously developed for this model, all spurious corrections to the dynamics of the solid-liquid interfaces linear in the interface thickness W can be eliminated. This means that, for small enough values of W , simulation results become independent of it. As a consequence, accurate results can be obtained using values of W much larger than the physical interface thickness, which yields a tremendous gain in computational power and makes simulations for realistic experimental parameters feasible. Convergence of the simulation outcome with decreasing W is explicitly demonstrated. Furthermore, the results are compared to a boundary-integral formulation of the corresponding free-boundary problem. Excellent agreement is found, except in the immediate vicinity of bifurcation points, a very sensitive situation where noticeable differences arise. These differences reveal that, in contrast to the standard assumptions of the free-boundary problem, out of equilibrium the diffuse trijunction region of the <span class="hlt">phase</span>-field model can (i) slightly deviate from Young’s law for the contact angles, and (ii) advance in a direction that forms a finite angle with the solid-solid interface at each instant. While the deviation (i) extrapolates to zero in the limit of vanishing interface thickness, the small angle in (ii) remains roughly constant</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JTePh..59.1101B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JTePh..59.1101B"><span><span class="hlt">Phase</span> transformations during the <span class="hlt">growth</span> of paracetamol crystals from the vapor <span class="hlt">phase</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Belyaev, A. P.; Rubets, V. P.; Antipov, V. V.; Bordei, N. S.</p> <p>2014-07-01</p> <p><span class="hlt">Phase</span> transformations during the <span class="hlt">growth</span> of paracetamol crystals from the vapor <span class="hlt">phase</span> are studied by differential scanning calorimetry. It is found that the vapor-crystal <span class="hlt">phase</span> transition is actually a superposition of two <span class="hlt">phase</span> transitions: a first-order <span class="hlt">phase</span> transition with variable density and a second-order <span class="hlt">phase</span> transition with variable ordering. The latter, being a diffuse <span class="hlt">phase</span> transition, results in the formation of a new, "pretransition," <span class="hlt">phase</span> irreversibly spent in the course of the transition, which ends in the appearance of orthorhombic crystals. X-ray diffraction data and micrograph are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM13D2541C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM13D2541C"><span>Magnetotail flux accumulation leading to auroral expansion and a <span class="hlt">substorm</span> current wedge: case study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chu, X.; McPherron, R. L.; Hsu, T. S.; Angelopoulos, V.; Weygand, J. M.; Strangeway, R. J.; Liu, J.</p> <p>2015-12-01</p> <p>Magnetotail burst busty flows, magnetic field dipolarization, and auroral poleward expansion are linked to the development of <span class="hlt">substorm</span> current wedges (SCW). Although auroral brightening is often attributed to field-aligned currents (FACs) in the SCW produced by flow vorticity and pressure redistribution, in-situ observations addressing the mechanism that generates these currents have been scarce. Conjugate observations and modelling results utilizing magnetotail satellites, inversion technique for SCW, and auroral imagers were used to study the release, transport, and accumulation of magnetic flux by flows; dipolarization associated with <span class="hlt">substorm</span> current wedge formation; and auroral poleward expansion during an isolated <span class="hlt">substorm</span> on 13 February 2008. During early expansion <span class="hlt">phase</span>, magnetic flux released by magnetic reconnection was transported by earthward flows. Some magnetic flux was accumulated in the near-Earth region, and the remainder was transported azimuthally by flow diversion. The accumulated flux created a high pressure region with vertically dipolarized and azimuthally bent magnetic field lines. The rotation of the magnetic field lines was consistent with the polarity of the SCW. In the near-Earth region, good agreement was found among the magnetic flux transported by the flows, the accumulated flux causing dipolarization inside the SCW, and the flux enclosed within the poleward-expanded auroral oval. This agreement demonstrates that magnetic flux from the flows accumulated and generated the SCW, the magnetic dipolarization, and the auroral poleward expansion. The quantity of accumulated flux appears to determine the amplitudes of these phenomena.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970000365','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970000365"><span><span class="hlt">Growth</span> and Morphology of <span class="hlt">Phase</span> Separating Supercritical Fluids</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hegseth, John; Beysens, Daniel; Perrot, Francoise; Nikolayev, Vadim; Garrabos, Yves</p> <p>1996-01-01</p> <p>The scientific objective is to study the relation between the morphology and the <span class="hlt">growth</span> kinetics of domains during <span class="hlt">phase</span> separation. We know from previous experiments performed near the critical point of pure fluids and binary liquids that there are two simple <span class="hlt">growth</span> laws at late times. The 'fast' <span class="hlt">growth</span> appears when the volumes of the <span class="hlt">phases</span> are nearly equal and the droplet pattern is interconnected. In this case the size of the droplets grows linearly in time. The 'slow' <span class="hlt">growth</span> appears when the pattern of droplets embedded in the majority <span class="hlt">phase</span> is disconnected. In this case the size of the droplets increases in proportion to time to the power 1/3. The volume fraction of the minority <span class="hlt">phase</span> is a good candidate to determine this change of behavior. All previous attempts to vary the volume fraction in a single experimental cell have failed because of the extreme experimental difficulties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SSRv..206...91M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SSRv..206...91M"><span>The Mid-Latitude Positive Bay and the MPB Index of <span class="hlt">Substorm</span> Activity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McPherron, Robert L.; Chu, Xiangning</p> <p>2017-03-01</p> <p><span class="hlt">Substorms</span> are a major source of magnetic activity. At <span class="hlt">substorm</span> expansion <span class="hlt">phase</span> onset a westward current flows through the expanding aurora. This current is the ionospheric closure of the <span class="hlt">substorm</span> current wedge produced by diversion of tail current along magnetic field lines. At low latitudes the field-aligned currents create a systematic pattern in the north (X) and east (Y) components of the surface magnetic field. The rise and decay in X is called a midlatitude positive bay whose start is a proxy for expansion onset. In this paper we describe a new index called the midlatitude positive bay index (MPB) which monitors the power in the <span class="hlt">substorm</span> perturbations of X and Y. The index is obtained by removing the main field, storm time variations, and the solar quiet (Sq) variation from the measured field. These are estimated with spline fits and principal component analysis. The residuals of X and Y are high pass filtered to eliminate variations with period longer than 3 hours. The sum of squares of the X and Y power is determined at each of 35 midlatitude stations. The average power in night time stations is the MPB index. The index series is standardized and intervals above a fixed threshold are taken as possible bay signatures. Post processing constrains these to have reasonable values of rise time, strength, and duration. Minima in the index before and after the peak are taken as the start and end of the bay. The MPB and AL indices can be used to identify quiet intervals in the magnetic field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SSRv..tmp...85M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SSRv..tmp...85M"><span>The Mid-Latitude Positive Bay and the MPB Index of <span class="hlt">Substorm</span> Activity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McPherron, Robert L.; Chu, Xiangning</p> <p>2016-11-01</p> <p><span class="hlt">Substorms</span> are a major source of magnetic activity. At <span class="hlt">substorm</span> expansion <span class="hlt">phase</span> onset a westward current flows through the expanding aurora. This current is the ionospheric closure of the <span class="hlt">substorm</span> current wedge produced by diversion of tail current along magnetic field lines. At low latitudes the field-aligned currents create a systematic pattern in the north (X) and east (Y) components of the surface magnetic field. The rise and decay in X is called a midlatitude positive bay whose start is a proxy for expansion onset. In this paper we describe a new index called the midlatitude positive bay index (MPB) which monitors the power in the <span class="hlt">substorm</span> perturbations of X and Y. The index is obtained by removing the main field, storm time variations, and the solar quiet (Sq) variation from the measured field. These are estimated with spline fits and principal component analysis. The residuals of X and Y are high pass filtered to eliminate variations with period longer than 3 hours. The sum of squares of the X and Y power is determined at each of 35 midlatitude stations. The average power in night time stations is the MPB index. The index series is standardized and intervals above a fixed threshold are taken as possible bay signatures. Post processing constrains these to have reasonable values of rise time, strength, and duration. Minima in the index before and after the peak are taken as the start and end of the bay. The MPB and AL indices can be used to identify quiet intervals in the magnetic field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22111928','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22111928"><span>High temperature <span class="hlt">growth</span> of Ag <span class="hlt">phases</span> on Ge(111)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mullet, Cory H.; Chiang, Shirley</p> <p>2013-03-15</p> <p>The <span class="hlt">growth</span> of the (3 Multiplication-Sign 1) and ({radical}3 Multiplication-Sign {radical}3)R30 Degree-Sign <span class="hlt">phases</span> of Ag on Ge(111) on substrates at temperatures from 540 to 660 Degree-Sign C is characterized with low energy electron microscopy (LEEM) and low energy electron diffraction (LEED). From 540 Degree-Sign C to the Ag desorption temperature of 575 Degree-Sign C, LEEM images show that <span class="hlt">growth</span> of the (3 Multiplication-Sign 1) <span class="hlt">phase</span> begins at step edges. Upon completion of the (3 Multiplication-Sign 1) <span class="hlt">phase</span>, the ({radical}3 Multiplication-Sign {radical}3)R30 Degree-Sign <span class="hlt">phase</span> is observed with a dendritic <span class="hlt">growth</span> morphology that is not much affected by steps. For sufficiently high deposition rates, Ag accumulates on the sample above the desorption temperature. From 575 to 640 Degree-Sign C, the <span class="hlt">growth</span> proceeded in a manner similar to that at lower temperatures, with <span class="hlt">growth</span> of the (3 Multiplication-Sign 1) <span class="hlt">phase</span> to completion, followed by <span class="hlt">growth</span> of the ({radical}3 Multiplication-Sign {radical}3)R30 Degree-Sign <span class="hlt">phase</span>. Increasing the substrate temperature to 660 Degree-Sign C resulted in only (3 Multiplication-Sign 1) <span class="hlt">growth</span>. In addition, for samples with Ag coverage less than 0.375ML, LEEM and LEED images were used to follow a reversible <span class="hlt">phase</span> transformation near 575 Degree-Sign C, between a mixed high coverage <span class="hlt">phase</span> of [(4 Multiplication-Sign 4) + (3 Multiplication-Sign 1)] and the high temperature, lower coverage (3 Multiplication-Sign 1) <span class="hlt">phase</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6966195','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6966195"><span>Nuclear magnetohydrodynamic EMP, solar storms, and <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rabinowitz, M. ); Meliopoulous, A.P.S.; Glytsis, E.N. . School of Electrical Engineering); Cokkinides, G.J. )</p> <p>1992-10-20</p> <p>In addition to a fast electromagnetic pulse (EMP), a high altitude nuclear burst produces a relatively slow magnetohydrodynamic EMP (MHD EMP), whose effects are like those from solar storm geomagnetically induced currents (SS-GIC). The MHD EMP electric field E [approx lt] 10[sup [minus] 1] V/m and lasts [approx lt] 10[sup 2] sec, whereas for solar storms E [approx gt] 10[sup [minus] 2] V/m and lasts [approx gt] 10[sup 3] sec. Although the solar storm electric field is lower than MHD EMP, the solar storm effects are generally greater due to their much longer duration. <span class="hlt">Substorms</span> produce much smaller effects than SS-GIC, but occur much more frequently. This paper describes the physics of such geomagnetic disturbances and analyzes their effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSA44A..08Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSA44A..08Z"><span>Deformation of Polar Cap Patches During <span class="hlt">Substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zou, S.; Ridley, A. J.; Nicolls, M. J.; Coster, A. J.; Thomas, E. G.; Ruohoniemi, J. M.; Hampton, D.</p> <p>2015-12-01</p> <p>Polar cap patches refer to the islands of high F-region plasma density within the polar cap. Their formation on the dayside and deformation on the nightside are not well understood. The F-layer ionosphere density is strongly influenced by electric field, thermospheric wind as well as soft particle precipitation. This study combines observations from multiple instruments, including Poker Flat incoherent scatter radar, GPS TEC and optical instruments, as well as the Global Ionosphere and Thermosphere Model (GITM), to investigate the effects of highly structured electric fields and winds on the deformation of polar cap patches during <span class="hlt">substorms</span>. We will also discuss variations of the auroral emissions associated with the patch evolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFMSM52B..07H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFMSM52B..07H"><span>Spatially Resolved <span class="hlt">Substorm</span> Dynamical Model with Internal and External <span class="hlt">Substorm</span> Triggers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Horton, W.; Crabtree, C.; Weigel, R. S.; Vassiliadis, D.; Doxas, I.</p> <p>2002-12-01</p> <p>A spatially-resolved nonlinear dynamics model of the coupled solar wind driven magnetosphere-ionosphere system is developed for the purpose of determining the electrical power flow from the solar wind through the nightside magnetosphere into the ionosphere. The model is derived from Maxwell equations and nonlinear plasma dynamics and focuses on the key conservation laws of mass, charge and energy in the power transfer elements in this complex dynamical system. The models has numerous feedback and feedforward loops for six forms of the distributed energy storage in the M-I system. In contrast to neural networks, the model delineates physically realizable time ordered sequence of energetic events in <span class="hlt">substorm</span> dynamics. Three types of energy releases are observed in the <span class="hlt">substorm</span> data and studied with the model. Type I events occur for solar wind conditions that lead to the creation of a near Earth neutral line (NENL) in the geomagnetic tail. Other solar wind conditions lead dominantly to the onset of convection in flux tubes with foot points in the auroral region that produced enhanced field aligned currents (FACs) closing in the ionosphere. These are the type II and type III events. In type II events a sudden northward turning of the IMF produces a transient mis-alignment of the pressure gradient with the gradient of the flux volumes as in the Lyons model. Large transient <span class="hlt">substorm</span> current wedge and auroral region 1 sense currents are driven by the steep near-Earth pressure gradient in these events type II events. In type III events the slower evolving IMF field directly drives the nightside M-I system. This is the directly driven auroral <span class="hlt">substorm</span>. We use physics-based filters to classify events in historical databases, and we use the 2-1/2D transport model to simulate the events for model solar wind inputs. The results of the research stress the need for more accurate determinations of the day-side magnetopause arrival times of structures in the solar wind required</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoRL..43.6687M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoRL..43.6687M"><span>SAPS onset timing during <span class="hlt">substorms</span> and the westward traveling surge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mishin, Evgeny, V.</p> <p>2016-07-01</p> <p>We present multispacecraft observations in the magnetosphere and conjugate ionosphere of the onset time of subauroral polarization streams (SAPS) and tens of keV ring current injections on the duskside in three individual <span class="hlt">substorms</span>. This is probably the first unequivocal determination of the <span class="hlt">substorm</span> SAPS onset timing. The time lag between the SAPS and <span class="hlt">substorm</span> onsets is much shorter than the gradient-curvature drift time of ˜10 keV ions in the plasmasphere. It seemingly depends on the propagation time of <span class="hlt">substorm</span>-injected plasma from the dipolarization onset region to the plasmasphere, as well as on the SAPS position. These observations suggest that fast onset SAPS and ring current injections are causally related to the two-loop system of the westward traveling surge.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980008091','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980008091"><span>The Physical Elements of Onset of the Magnetospheric <span class="hlt">Substorm</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>1997-01-01</p> <p>During this reporting period effort continued in the areas: (1) understanding the mechanisms responsible for <span class="hlt">substorm</span> onset, and (2) application of a fundamental description of field-aligned currents and parallel electric fields to the plasma-sheet boundary layer.</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('https://ntrs.nasa.gov/search.jsp?R=19820060659&hterms=gatos&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dgatos','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820060659&hterms=gatos&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dgatos"><span>In situ monitoring of liquid <span class="hlt">phase</span> electroepitaxial <span class="hlt">growth</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Okamoto, A.; Isozumi, S.; Lagowski, J.; Gatos, H. C.</p> <p>1982-01-01</p> <p>In situ monitoring of the layer thickness during liquid <span class="hlt">phase</span> electroepitaxy (LPEE) was achieved with a submicron resolution through precise resistance measurements. The new approach to the study and control of LPEE was applied to <span class="hlt">growth</span> of undoped and Ge-doped GaAs layers. The in situ determined <span class="hlt">growth</span> kinetics was found to be in excellent agreement with theory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5132797','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5132797"><span>Multipoint observations of a small <span class="hlt">substorm</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lopez, R.E. Applied Research Corp., Landover, MD ); Luehr, H. ); Anderson, B.J.; Newell, P.T.; McEntire, R.W. )</p> <p>1990-11-01</p> <p>In this paper the authors present multipoint observations of a small <span class="hlt">substorm</span> which occurred just after 0110 UT on April 25, 1985. The observations were made by spacecraft (AMPTE CCE, AMPTE IRM, DMSP F6, and DMSP F7), ground auroral stations (EISCAT magnetometer cross, Syowa, Narssarssuaq, Great Whale River, and Fort Churchill), and mid-latitude stations (Furstenfeldbruck, Toledo, and Argentine Island). These data provide them with a broad range of observations, including the latitudinal extent of the polar cap, visual identification of <span class="hlt">substorm</span> aurorae and the magnetic perturbations produced directly beneath them, in situ magnetic field and energetic particle observations of the disruption of the cross-tail current sheet, and observations concerning the spatial expansion of the current disruption region from two radially aligned spacecraft. The DMSP data indicate that the event took place during a period when the polar cap was relatively contracted, yet the disruption of the current sheet was observed by CCE at 8.56 R{sub E}. They have been able to infer a considerable amount of detail concerning the structure and westward expansion of the auroral features associated with the event, and they show that those auroral surges were located more than 10{degree} equatorward of the boundary between open and closed field lines. Moreover, they present evidence that the current sheet disruption observed by CCE in the neutral sheet was located on field lines which mapped to the westward traveling surge observed directly overhead of the ground station at Syowa. Furthermore, the observations strongly imply that disruption of the cross-tail current began in the near-Earth region and that it had a component of expansion which was radially antisunward.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SunGe..11..105D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SunGe..11..105D"><span>Comparison of <span class="hlt">substorms</span> near two solar cycle maxima: (1999-2000 and 2012-2013)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Despirak, I.; Lubchich, A.; Kleimenova, N.</p> <p>2016-05-01</p> <p>We present the comparative analysis of the <span class="hlt">substorm</span> behavior during two solar cycle maxima. The <span class="hlt">substorms</span>, observed during the large solar cycle maximum (1999- 2000, with Wp> 100) and during the last maximum (2012-2013 with Wp~60), were studied. The considered <span class="hlt">substorms</span> were divided into 3 types according to auroral oval dynamic. First type - <span class="hlt">substorms</span> which are observed only at auroral latitudes ("usual" <span class="hlt">substorms</span>); second type - <span class="hlt">substorms</span> which propagate from auroral latitudes (<70?) to polar geomagnetic latitudes (>70°) ("expanded" <span class="hlt">substorms</span>, according to expanded oval); third type - <span class="hlt">substorms</span> which are observed only at latitudes above ~70° in the absence of simultaneous geomagnetic disturbances below 70° ("polar" <span class="hlt">substorms</span>, according to contracted oval). Over 1700 <span class="hlt">substorm</span> events have been analyzed. The following <span class="hlt">substorm</span> characteristics have been studied: (i) the seasonal variations, (ii) the latitudinal range of the occurrence, (iii) solar wind and IMF parameters before <span class="hlt">substorm</span> onset, (iiii) PC-index before <span class="hlt">substorm</span> onset. Thus, the difference between two solar activity maxima could be seen in the difference of <span class="hlt">substorm</span> behavior in these periods as well.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25000349','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25000349"><span>Crystal <span class="hlt">growth</span> within a <span class="hlt">phase</span> change memory cell.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sebastian, Abu; Le Gallo, Manuel; Krebs, Daniel</p> <p>2014-07-07</p> <p>In spite of the prominent role played by <span class="hlt">phase</span> change materials in information technology, a detailed understanding of the central property of such materials, namely the <span class="hlt">phase</span> change mechanism, is still lacking mostly because of difficulties associated with experimental measurements. Here, we measure the crystal <span class="hlt">growth</span> velocity of a <span class="hlt">phase</span> change material at both the nanometre length and the nanosecond timescale using <span class="hlt">phase</span>-change memory cells. The material is studied in the technologically relevant melt-quenched <span class="hlt">phase</span> and directly in the environment in which the <span class="hlt">phase</span> change material is going to be used in the application. We present a consistent description of the temperature dependence of the crystal <span class="hlt">growth</span> velocity in the glass and the super-cooled liquid up to the melting temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/2533532','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/2533532"><span>Heracleum mantegazzianum <span class="hlt">growth</span> <span class="hlt">phases</span> and furocoumarin content.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pira, E; Romano, C; Sulotto, F; Pavan, I; Monaco, E</p> <p>1989-11-01</p> <p>The observation of photocontact dermatitis from Heracleum mantegazzianum Sommier et Levier in 2 gardeners at work prompted the analysis of furocoumarin content of stem, leaves and fruits of the plant during a period of 1 year. Their concentration was found to be maximal in fruit, intermediate in leaf, and minimal in stem. Psoralen was the most prevalent substance in the leaf and bergapten in the fruit. In the stem, in contrast, individual furocoumarins were found in lower but variable concentrations. 3 furocoumarin seasonal peaks were observed in the leaf: the maximal peak occurred in June, the intermediate in August, the minimal in November. This trend corresponds to 3 biological <span class="hlt">phases</span> of the weed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/786478','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/786478"><span>Dynamic Particle <span class="hlt">Growth</span> Testing - <span class="hlt">Phase</span> I Studies</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hu, M.Z-C.</p> <p>2001-05-17</p> <p>There is clearly a great need to understand the processes of crystallization and solid scale formation that led to the shutdown of 2H evaporator operation at the Savannah River Site (SRS) and could possibly cause similar problems in the future in other evaporators. Waste streams from SRS operations that enter the evaporators generally contain alkaline, sodium nitrate/nitrite-based solutions with various changing concentrations of silicates and aluminates. It has been determined. that the silicates and aluminates served as precursor reactants for forming unwanted minerals during solution evaporation, upon transport, or upon storage. Mineral forms of the Zeolite Linde A group--sodalites and cancrinite--along with gibbsite, have often been identified as contributing to deposit (scale) formation on surfaces of the 2H evaporator as well as to the formation of solid plugs in the gravity drain line and lift line. Meanwhile, solids (amorphous or crystalline minerals) are believed, without direct evidence, to form in the bulk solutions in the evaporator. In addition, the position of deposits in the 2H evaporator suggests that scale formation depends on the interplay of heat and mass transfer, hydrodynamics, and reaction mechanisms and kinetics. The origin of solid scale formation on walls could be due to heterogeneous nucleation and/or to homogeneous nucleation followed by cluster/particle deposition. Preliminary laboratory tests at the Savannah River Technology Center (SRTC) with standing metal coupons seem to support the latter mechanism for initial deposition; that is, the solid particles form in the bulk solution first and then deposit on the metal surfaces. Further buildup of deposits may involve both mechanisms: deposition and crystal <span class="hlt">growth</span>. Therefore, there may be a direct linkage between the solid particle <span class="hlt">growth</span> in bulk solution and the scale buildup on the wall surfaces. On the other hand, even if scale formation is due solely to a heterogeneous mechanism</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/752145','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/752145"><span><span class="hlt">Phase</span> transformation and <span class="hlt">growth</span> of hygroscopic aerosols</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tang, I.N.</p> <p>1999-11-01</p> <p>Ambient aerosols play an important role in many atmospheric processes affecting air quality, visibility degradation, and climatic changes as well. Both natural and anthropogenic sources contribute to the formation of ambient aerosols, which are composed mostly of sulfates, nitrates, and chlorides in either pure or mixed forms. These inorganic salt aerosols are hygroscopic by nature and exhibit the properties of deliquescence and efflorescence in humid air. For pure inorganic salt particles with diameter larger than 0.1 micron, the <span class="hlt">phase</span> transformation from a solid particle to a saline droplet occurs only when the relative humidity in the surrounding atmosphere reaches a certain critical level corresponding to the water activity of the saturated solution. The droplet size or mass in equilibrium with relative humidity can be calculated in a straightforward manner from thermodynamic considerations. For aqueous droplets 0.1 micron or smaller, the surface curvature effect on vapor pressure becomes important and the Kelvin equation must be used.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MNRAS.459.3326A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MNRAS.459.3326A"><span>The quiescent <span class="hlt">phase</span> of galactic disc <span class="hlt">growth</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aumer, Michael; Binney, James; Schönrich, Ralph</p> <p>2016-07-01</p> <p>We perform a series of controlled N-body simulations of growing disc galaxies within non-growing, live dark matter haloes of varying mass and concentration. Our initial conditions include either a low-mass disc or a compact bulge. New stellar particles are continuously added on near-circular orbits to the existing disc, so spiral structure is continuously excited. To study the effect of combined spiral and giant molecular cloud (GMC) heating on the discs, we introduce massive, short-lived particles that sample a GMC mass function. An isothermal gas component is introduced for a subset of the models. We perform a resolution study and vary parameters governing the GMC population, the histories of star formation and radial scale <span class="hlt">growth</span>. Models with GMCs and standard values for the disc mass and halo density provide the right level of self-gravity to explain the age-velocity dispersion relation of the solar neighbourhood (Snhd). GMC heating generates remarkably exponential vertical profiles with scaleheights that are radially constant and agree with observations of galactic thin discs. GMCs are also capable of significantly delaying bar formation. The amount of spiral-induced radial migration agrees with what is required for the metallicity distribution of the Snhd. However, in our standard models, the outward-migrating populations are not hot enough vertically to create thick discs. Thick discs can form in models with high baryon fractions, but the corresponding bars are too long, the young stellar populations too hot and the discs flare considerably.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26363098','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26363098"><span><span class="hlt">Growth</span> <span class="hlt">phase</span>-dependent composition of the Helicobacter pylori exoproteome.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Snider, Christina A; Voss, Bradley J; McDonald, W Hayes; Cover, Timothy L</p> <p>2016-01-01</p> <p>Helicobacter pylori colonizes the human stomach and is associated with an increased risk of gastric cancer and peptic ulcer disease. Analysis of H. pylori protein secretion is complicated by the occurrence of bacterial autolysis. In this study, we analyzed the exoproteome of H. pylori at multiple <span class="hlt">phases</span> of bacterial <span class="hlt">growth</span> and identified 74 proteins that are selectively released into the extracellular space. These include proteins known to cause alterations in host cells, antigenic proteins, and additional proteins that have not yet been studied in any detail. The composition of the H. pylori exoproteome is dependent on the <span class="hlt">phase</span> of bacterial <span class="hlt">growth</span>. For example, the proportional abundance of the vacuolating toxin VacA in culture supernatant is higher during late <span class="hlt">growth</span> <span class="hlt">phases</span> than early <span class="hlt">growth</span> <span class="hlt">phases</span>, whereas the proportional abundance of many other proteins is higher during early <span class="hlt">growth</span> <span class="hlt">phases</span>. We detected marked variation in the subcellular localization of putative secreted proteins within soluble and membrane fractions derived from intact bacteria. By providing a comprehensive view of the H. pylori exoproteome, these results provide new insights into the array of secreted H. pylori proteins that may cause alterations in the gastric environment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSM23C4253F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSM23C4253F"><span>Elements of M-I Coupling in Repetitive <span class="hlt">Substorm</span> Activity Driven by Interplanetary CMEs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Farrugia, C. J.; Sandholt, P. E.</p> <p>2014-12-01</p> <p>By means of case studies we explore key elements of the magnetosphere-ionosphere current system associated with repetitive <span class="hlt">substorm</span> activity during persistent strong forcing by ICMEs. Our approach consists of a combination of the magnetospheric and ionospheric perspectives on the <span class="hlt">substorm</span> activity. The first aspect is the near-Earth plasma sheet with its repetitive excitations of the <span class="hlt">substorm</span> current wedge, as monitored by spacecraft GOES-10 when it traversed the 2100-0300 MLT sector, and its coupling to the westward auroral electrojet (WEJ) centered near midnight during the stable interplanetary (IP) conditions. The second aspect is the excitation of Bostrom type II currents maximizing at dusk and dawn and their associated ionospheric Pedersen current closure giving rise to EEJ (WEJ) events at dusk (dawn). As documented in our study, this aspect is related to the braking <span class="hlt">phase</span> of Earthward-moving dipolarization fronts-bursty bulk flows. We follow the magnetospheric flow/field events from spacecraft Geotail in the midtail (X = - 11 Re) lobe to geostationary altitude at pre-dawn MLTs (GOES 10). The associated M-I coupling is obtained from ground-satellite conjunctions across the double auroral oval configuration along the meridian at dusk. By this technique we distinguish between ionospheric manifestations in three latitude regimes: (i) auroral oval south, (ii) auroral oval north, and (iii) polar cap. Regime (iii) is characterized by events of enhanced antisunward convection near the polar cap boundary (flow channel events) and in the central polar cap (PCN-index events). The repetitive <span class="hlt">substorm</span> activity is discussed in the context of the level of IP driving as given by the geoeffective IP electric field (E_KL), magnetotail reconnection (inferred from the PCN-index and spacecraft Wind at X = - 77 Re) and the storm SYM-H index. We distinguish between different variants of the repetitive <span class="hlt">substorm</span> activity, giving rise to electrojet (AL)-plasma convection (PCN) events</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMSM11A2289H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMSM11A2289H"><span>Seasonal dependence of the <span class="hlt">substorm</span> overshielding at the subauroral latitude</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hashimoto, K. K.; Kikuchi, T.</p> <p>2012-12-01</p> <p>We have shown that the equatorial counter electrojet (CEJ) is observed on the dayside when the overshielding electric field is dominant at subauroral latitudes on the dusk during <span class="hlt">substorm</span> expansion <span class="hlt">phase</span>. In this study, we examine if all the equatorial CEJs are accompanied by overshielding at subauroral latitudes by using ground magnetometer networks, IMAGE and INTERMAGNET during the period from 2000 to 2003. We selected 469 CEJ events from magnetometer data at Huancayo in Peru observed with the positive bay at Kakioka, Japan on the nightside. Overshielding was observed at subauroral stations of the IMAGE for 263 CEJ events, while it was not observed for 206 events. We found that the occurrence of the overshielding at subauroral latitudes significantly depends on the season; they tend to occur in the winter period from November to February. On the other hand, the convection electric field is dominant at the subauroral latitude during the northern summer period from April to August. Overshielding electric field that causes the CEJ during the northern summer should be originated from the southern hemisphere. Our results suggest that the overshielding electric field is stronger in winter than in summer if the convection electric field does not depend on the season. These features would be explained by assuming that the dynamo for the Region-1 field-aligned currents (R1 FACs) is the voltage generator, while that for the R2 FACs is the current generator.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JGRA..11510209F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JGRA..11510209F"><span>Small and meso-scale properties of a <span class="hlt">substorm</span> onset auroral arc</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Frey, H. U.; Amm, O.; Chaston, C. C.; Fu, S.; Haerendel, G.; Juusola, L.; Karlsson, T.; Lanchester, B.; Nakamura, R.; Østgaard, N.; Sakanoi, T.; Séran, E.; Whiter, D.; Weygand, J.; Asamura, K.; Hirahara, M.</p> <p>2010-10-01</p> <p>We present small and meso-scale properties of a <span class="hlt">substorm</span> onset arc observed simultaneously by the Reimei and THEMIS satellites together with ground-based observations by the THEMIS GBO system. The optical observations revealed the slow equatorward motion of the <span class="hlt">growth-phase</span> arc and the development of a much brighter onset arc poleward of it. Both arcs showed the typical particle signature of electrostatic acceleration in an inverted-V structure together with a strong Alfvén wave acceleration signature at the poleward edge of the onset arc. Two THEMIS spacecraft encountered earthward flow bursts around the times the expanding optical aurora reached their magnetic footprints in the ionosphere. The particle and field measurements allowed for the reconstruction of the field-aligned current system and the determination of plasma properties in the auroral source region. Auroral arc properties were extracted from the optical and particle measurements and were used to compare measured values to theoretical predictions of the electrodynamic model for the generation of auroral arcs. Good agreement could be reached for the meso-scale arc properties. A qualitative analysis of the internal structuring of the bright onset arc suggests the operation of the tearing instability which provides a 'rope-like' appearance due to advection of the current in the sheared flow across the arc. We also note that for the observed parameters ionospheric conductivity gradients due to electron precipitation will be unstable to the feedback instability in the ionospheric Alfvén resonator that can drive structuring in luminosity over the range of scales observed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/310022','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/310022"><span>Physical Processes of <span class="hlt">Substorm</span> Onset and Current Disruption Observed by AMPTE/CCE</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cheng, C.Z.; Lui, A.T.Y.</p> <p>1998-03-01</p> <p>A new scenario of AMPTE/CCE observation of <span class="hlt">substorm</span> onset and current disruption and the corresponding physical processes is presented. Toward the end of the late <span class="hlt">growth</span> <span class="hlt">phase</span>, plasma beta increases to greater than or equal to 50 and a low-frequency instability with a wave period of 50-75 seconds is excited and grows exponentially to a large amplitude at the onset of current disruption. At the current disruption onset, higher-frequency instabilities are excited so that the plasma and electromagnetic field form a turbulent state. Plasma transport and heating take place to reduce plasma beta and modify the ambient plasma pressure and velocity profiles so that the ambient magnetic field recovers from a tail-like geometry to a more dipole- like geometry. To understand the excitation of the low-frequency global instability, a new theory of kinetic ballooning instability (KBI) is proposed to explain the high critical beta threshold (greater than or equal to 50) of the low-frequency global instability observed by the AMPTE/CCE. The stabilization kinetic effects of trapped electron and finite ion Larmor radii give rise to a large parallel electric field and hence a parallel current that greatly enhances the stabilizing effect of field line tension to the ballooning mode. As a result, the high critical beta threshold for excitation of KBI is greatly increased over the ideal MHD ballooning instability threshold by greater than O(10 squared). The wave-ion magnetic drift resonance effect typically reduces the high critical beta threshold by up to 20% and produces a perturbed resonant ion velocity distribution with a duskward velocity roughly equal to the average ion magnetic drift velocity as the KBI grows to a large amplitude. Higher-frequency instabilities, such as the cross-field current instability (CCI), can be excited by the additional velocity space free energy associated with the positive slope in the perturbed resonant ion velocity distribution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PMag...91..183T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PMag...91..183T"><span>The <span class="hlt">phase</span>-field model in tumor <span class="hlt">growth</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Travasso, Rui D. M.; Castro, Mario; Oliveira, Joana C. R. E.</p> <p>2011-01-01</p> <p>Tumor <span class="hlt">growth</span> is becoming a central problem in biophysics both from its social and medical interest and, more fundamentally, because it is a remarkable example of an emergent complex system. Focusing on the description of the spatial and dynamical features of tumor <span class="hlt">growth</span>, in this paper we review recent tumor modeling approaches using a technique borrowed from materials science: the <span class="hlt">phase</span>-field models. These models allow us, with a large degree of generality, to identify the paramount mechanisms causing the uncontrolled <span class="hlt">growth</span> of tumor cells as well as to propose new guidelines for experimentation both in simulation and in the laboratory. We finish by discussing open directions of research in <span class="hlt">phase</span>-field modeling of tumor <span class="hlt">growth</span> to catalyze the interest of physicists and mathematicians in this emergent field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6052652','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6052652"><span>Correlative comparison of geomagnetic storms and auroral <span class="hlt">substorms</span> using geomagnetic indeces. Master's thesis</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cade, W.B.</p> <p>1993-06-01</p> <p>Partial contents include the following: (1) Geomagnetic storm and <span class="hlt">substorm</span> processes; (2) Magnetospheric structure; (3) <span class="hlt">Substorm</span> processes; (4) Data description; (5) Geomagnetic indices; and (6) Data period and data sets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhyA..392.6616I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhyA..392.6616I"><span><span class="hlt">Phase</span> transition in tumor <span class="hlt">growth</span>: I avascular development</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Izquierdo-Kulich, E.; Rebelo, I.; Tejera, E.; Nieto-Villar, J. M.</p> <p>2013-12-01</p> <p>We propose a mechanism for avascular tumor <span class="hlt">growth</span> based on a simple chemical network. This model presents a logistic behavior and shows a “second order” <span class="hlt">phase</span> transition. We prove the fractal origin of the empirical logistics and Gompertz constant and its relation to mitosis and apoptosis rate. Finally, the thermodynamics framework developed demonstrates the entropy production rate as a Lyapunov function during avascular tumor <span class="hlt">growth</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhyA..426...88L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhyA..426...88L"><span><span class="hlt">Phase</span> transitions in tumor <span class="hlt">growth</span>: II prostate cancer cell lines</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Llanos-Pérez, J. A.; Betancourt-Mar, A.; De Miguel, M. P.; Izquierdo-Kulich, E.; Royuela-García, M.; Tejera, E.; Nieto-Villar, J. M.</p> <p>2015-05-01</p> <p>We propose a mechanism for prostate cancer cell lines <span class="hlt">growth</span>, LNCaP and PC3 based on a Gompertz dynamics. This <span class="hlt">growth</span> exhibits a multifractal behavior and a "second order" <span class="hlt">phase</span> transition. Finally, it was found that the cellular line PC3 exhibits a higher value of entropy production rate compared to LNCaP, which is indicative of the robustness of PC3, over to LNCaP and may be a quantitative index of metastatic potential tumors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970027552','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970027552"><span>Solar Wind-Magnetosphere Coupling During an Isolated <span class="hlt">Substorm</span> Event: A Multispacecraft ISTP Study</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pulkkinen, T. I.; Baker, D. N.; Turner, N. E.; Singer, H. J.; Frank, L. A.; Sigwarth, J. B.; Scudder, J.; Anderson, R.; Kokubun, S.; Mukai, T.; Nakamura, R.; Blake, J. B.; Russell, C. T.; Kawano, H.; Mozer, F.; Slavin, J. A.</p> <p>1997-01-01</p> <p>Multispacecraft data from the upstream solar wind, polar cusp, and inner magnetotail are used to show that the polar ionosphere responds within a few minutes to a southward IMF turning, whereas the inner tail signatures are visible within ten min from the southward turning. Comparison of two subsequent <span class="hlt">substorm</span> onsets, one during southward and the other during northward IMF, demonstrates the dependence of the expansion <span class="hlt">phase</span> characteristics on the external driving conditions. Both onsets are shown to have initiated in the midtail, with signatures in the inner tail and auroral oval following a few minutes later.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850015098','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850015098"><span>Periodic <span class="hlt">substorm</span> activity in the geomagnetic tail</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Huang, C. Y.; Eastman, T. E.; Frank, L. A.; Williams, D. J.</p> <p>1983-01-01</p> <p>On 19 May 1978 an anusual series of events is observed with the Quadrispherical LEPEDEA on board the ISEE-1 satellite in the Earth's geomagnetic tail. For 13 hours periodic bursts of both ions and electrons are seen in all the particle detectors on the spacecraft. On this day periodic activity is also seen on the ground, where multiple intensifications of the electrojets are observed. At the same time the latitudinal component of the interplanetary magnetic field shows a number of strong southward deflections. It is concluded that an extended period of <span class="hlt">substorm</span> activity is occurring, which causes repeated thinnings and recoveries of the plasma sheet. These are detected by ISEE, which is situated in the plasma sheet boundary layer, as periodic dropouts and reappearances of the plasma. Comparisons of the observations at ISEE with those at IMP-8, which for a time is engulfed by the plasma sheet, indicate that the activity is relatively localized in spatial extent. For this series of events it is clear that a global approach to magnetospheric dynamics, e.g., reconnection, is inappropriate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..122..349K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..122..349K"><span>Particle energization by a <span class="hlt">substorm</span> dipolarization</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kabin, K.; Kalugin, G.; Donovan, E.; Spanswick, E.</p> <p>2017-01-01</p> <p>Magnetotail dipolarizations, often associated with <span class="hlt">substorms</span>, produce significant energetic particle enhancements in the nighttime magnetosphere. In this paper, we apply our recently developed magnetotail dipolarization model to the problem of energizing electrons and ions. Our model is two-dimensional in the meridional plane and is characterized by the ability to precisely control the location of the transition from the dipole-like to tail-like magnetic fields. Both magnetic and electric fields are calculated, self-consistently, as the transition zone retreats farther into the tail and the area around the Earth occupied by dipole-like lines increases in size. These fields are used to calculate the motion of electrons and ions and changes in their energies. We consider the energizing effects of the fields restricted to ±15° and ±30° sectors around the midnight meridian, as well the axisymmetric case. Energies of some electrons increase by a factor of 25, which is more than enough to produce observable ionospheric signatures. Electrons are treated using the Guiding Center approximation, while protons and heavier particles generally require description based on the Lorentz equations.</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('https://www.ncbi.nlm.nih.gov/pubmed/22139505','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22139505"><span>Lag <span class="hlt">phase</span> is a distinct <span class="hlt">growth</span> <span class="hlt">phase</span> that prepares bacteria for exponential <span class="hlt">growth</span> and involves transient metal accumulation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rolfe, Matthew D; Rice, Christopher J; Lucchini, Sacha; Pin, Carmen; Thompson, Arthur; Cameron, Andrew D S; Alston, Mark; Stringer, Michael F; Betts, Roy P; Baranyi, József; Peck, Michael W; Hinton, Jay C D</p> <p>2012-02-01</p> <p>Lag <span class="hlt">phase</span> represents the earliest and most poorly understood stage of the bacterial <span class="hlt">growth</span> cycle. We developed a reproducible experimental system and conducted functional genomic and physiological analyses of a 2-h lag <span class="hlt">phase</span> in Salmonella enterica serovar Typhimurium. Adaptation began within 4 min of inoculation into fresh LB medium with the transient expression of genes involved in phosphate uptake. The main lag-<span class="hlt">phase</span> transcriptional program initiated at 20 min with the upregulation of 945 genes encoding processes such as transcription, translation, iron-sulfur protein assembly, nucleotide metabolism, LPS biosynthesis, and aerobic respiration. ChIP-chip revealed that RNA polymerase was not "poised" upstream of the bacterial genes that are rapidly induced at the beginning of lag <span class="hlt">phase</span>, suggesting a mechanism that involves de novo partitioning of RNA polymerase to transcribe 522 bacterial genes within 4 min of leaving stationary <span class="hlt">phase</span>. We used inductively coupled plasma mass spectrometry (ICP-MS) to discover that iron, calcium, and manganese are accumulated by S. Typhimurium during lag <span class="hlt">phase</span>, while levels of cobalt, nickel, and sodium showed distinct <span class="hlt">growth-phase</span>-specific patterns. The high concentration of iron during lag <span class="hlt">phase</span> was associated with transient sensitivity to oxidative stress. The study of lag <span class="hlt">phase</span> promises to identify the physiological and regulatory processes responsible for adaptation to new environments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19880051672&hterms=energy+input&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Denergy%2Binput','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19880051672&hterms=energy+input&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Denergy%2Binput"><span>The roles of direct input of energy from the solar wind and unloading of stored magnetotail energy in driving magnetospheric <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rostoker, G.; Akasofu, S. I.; Baumjohann, W.; Kamide, Y.; Mcpherron, R. L.</p> <p>1987-01-01</p> <p>The contributions to the <span class="hlt">substorm</span> expansive <span class="hlt">phase</span> of direct energy input from the solar wind and from energy stored in the magnetotail which is released in an unpredictable manner are considered. Two physical processes for the dispensation of the energy input from the solar wind are identified: (1) a driven process in which energy supplied from the solar wind is directly dissipated in the ionosphere; and (2) a loading-unloading process in which energy from the solar wind is first stored in the magnetotail and then is suddenly released to be deposited in the ionosphere. The pattern of <span class="hlt">substorm</span> development in response to changes in the interplanetary medium has been elucidated for a canonical isolated <span class="hlt">substorm</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19880051672&hterms=solar+direct+energy&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dsolar%2Bdirect%2Benergy','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19880051672&hterms=solar+direct+energy&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dsolar%2Bdirect%2Benergy"><span>The roles of direct input of energy from the solar wind and unloading of stored magnetotail energy in driving magnetospheric <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rostoker, G.; Akasofu, S. I.; Baumjohann, W.; Kamide, Y.; Mcpherron, R. L.</p> <p>1987-01-01</p> <p>The contributions to the <span class="hlt">substorm</span> expansive <span class="hlt">phase</span> of direct energy input from the solar wind and from energy stored in the magnetotail which is released in an unpredictable manner are considered. Two physical processes for the dispensation of the energy input from the solar wind are identified: (1) a driven process in which energy supplied from the solar wind is directly dissipated in the ionosphere; and (2) a loading-unloading process in which energy from the solar wind is first stored in the magnetotail and then is suddenly released to be deposited in the ionosphere. The pattern of <span class="hlt">substorm</span> development in response to changes in the interplanetary medium has been elucidated for a canonical isolated <span class="hlt">substorm</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhyA..462..560L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhyA..462..560L"><span><span class="hlt">Phase</span> transitions in tumor <span class="hlt">growth</span>: III vascular and metastasis behavior</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Llanos-Pérez, J. A.; Betancourt-Mar, J. A.; Cocho, G.; Mansilla, R.; Nieto-Villar, José Manuel</p> <p>2016-11-01</p> <p>We propose a mechanism for avascular, vascular and metastasis tumor <span class="hlt">growth</span> based on a chemical network model. Vascular <span class="hlt">growth</span> and metastasis, appear as a hard <span class="hlt">phase</span> transition type, as ;first order;, through a supercritical Andronov-Hopf bifurcation, emergence of limit cycle and then through a cascade of bifurcations type saddle-foci Shilnikov's bifurcation. Finally, the thermodynamics framework developed shows that the entropy production rate, as a Lyapunov function, indicates the directional character and stability of the dynamical behavior of tumor <span class="hlt">growth</span> according to this model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM43C..08H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM43C..08H"><span>Empirical evidence for two nightside current wedges during <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hoffman, R. A.; Gjerloev, J. W.</p> <p>2013-12-01</p> <p>We present results from a comprehensive statistical study of the ionospheric current system and its coupling to the magnetosphere during classical bulge type <span class="hlt">substorms</span>. We identified 116 <span class="hlt">substorms</span> and determined the global ionospheric current system before and during the <span class="hlt">substorm</span> using the SuperMAG initiative and global auroral images obtained by the Polar VIS Earth camera. The westward electrojet (WEJ) display a distinct latitudinal shift between the pre- and post-midnight region and we find evidence that the two WEJ regions are disconnected. This, and other observational facts, led us to propose a new 3D current system configuration that consists of 2 wedge type systems: a current wedge in the pre-midnight region (<span class="hlt">substorm</span> current wedge), and another current wedge system in the post-midnight region (oval current wedge). There is some local time overlap between the two systems. The former maps to the region inside the near Earth neutral line and is associated with structured BPS type electron precipitation. The latter maps to the inner magnetosphere and is associated with diffuse electron precipitation. We present results of the statistical study, show typical events, results from Biot-Savart simulations, and discuss the implications for our understanding of the 3D current system associated with <span class="hlt">substorms</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010047012&hterms=association&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dassociation','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010047012&hterms=association&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dassociation"><span>Association of Energetic Neutral Atom Bursts and Magnetospheric <span class="hlt">Substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jorgensen, A. M.; Kepko, L.; Henderson, M. G.; Spence, H. E.; Reeves, G. D.; Sigwarth, J. B.; Frank, L. A.</p> <p>2000-01-01</p> <p>In this paper we present evidence that short-lived bursts of energetic neutral atoms (ENAs) observed with the Comprehensive Energetic Particle and Pitch Angle Distribution/Imaging Proton Spectrometer (CEPPAD/IPS) instrument on the Polar spacecraft are signatures of <span class="hlt">substorms</span>. The IPS was designed primarily to measure ions in situ, with energies between 17.5 and 1500 keV. However, it has also proven to be a very capable ENA imager in the range 17.5 keV to a couple hundred keV. It was expected that some ENA signatures of the storm time ring current would be observed. Interestingly, IPS also routinely measures weaker, shorter-lived, and more spatially confined bursts of ENAs with duration from a few tens of minutes to a few hours and appearing once or twice a day. One of these bursts was quickly associated with magnetospheric and auroral <span class="hlt">substorm</span> activity and has been reported in the literature [Henderson et al., 19971. In this paper we characterize ENA bursts observed from Polar and establish statistically their association with classic <span class="hlt">substorm</span> signatures (global auroral onsets, electron and ion injections, AL drops, and Pi2 onsets). We conclude that -90% of the observed ENA bursts are associated with classic <span class="hlt">substorms</span> and thus represent a new type of <span class="hlt">substorm</span> signature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010047012&hterms=atom+particle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Datom%2Bparticle','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010047012&hterms=atom+particle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Datom%2Bparticle"><span>Association of Energetic Neutral Atom Bursts and Magnetospheric <span class="hlt">Substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jorgensen, A. M.; Kepko, L.; Henderson, M. G.; Spence, H. E.; Reeves, G. D.; Sigwarth, J. B.; Frank, L. A.</p> <p>2000-01-01</p> <p>In this paper we present evidence that short-lived bursts of energetic neutral atoms (ENAs) observed with the Comprehensive Energetic Particle and Pitch Angle Distribution/Imaging Proton Spectrometer (CEPPAD/IPS) instrument on the Polar spacecraft are signatures of <span class="hlt">substorms</span>. The IPS was designed primarily to measure ions in situ, with energies between 17.5 and 1500 keV. However, it has also proven to be a very capable ENA imager in the range 17.5 keV to a couple hundred keV. It was expected that some ENA signatures of the storm time ring current would be observed. Interestingly, IPS also routinely measures weaker, shorter-lived, and more spatially confined bursts of ENAs with duration from a few tens of minutes to a few hours and appearing once or twice a day. One of these bursts was quickly associated with magnetospheric and auroral <span class="hlt">substorm</span> activity and has been reported in the literature [Henderson et al., 19971. In this paper we characterize ENA bursts observed from Polar and establish statistically their association with classic <span class="hlt">substorm</span> signatures (global auroral onsets, electron and ion injections, AL drops, and Pi2 onsets). We conclude that -90% of the observed ENA bursts are associated with classic <span class="hlt">substorms</span> and thus represent a new type of <span class="hlt">substorm</span> signature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EP%26S...67..170T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EP%26S...67..170T"><span>PC index as a proxy of the solar wind energy that entered into the magnetosphere: 2. Relation to the interplanetary electric field E KL before <span class="hlt">substorm</span> onset</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Troshichev, OA; Sormakov, DA</p> <p>2015-10-01</p> <p>This paper (the second of a series) presents the results of statistical investigation of relationship between the interplanetary electric field E KL and the Polar Cap (PC) index in case of magnetic <span class="hlt">substorms</span> (1998-2001), which have been analyzed in Troshichev et al. (J. Geophys. Res. Space Physics, 119, 2014). The PC index is directly related to the E KL field variations on interval preceding the <span class="hlt">substorm</span> sudden onset (SO): correlation R > 0.5 is typical of more than 90 % of isolated <span class="hlt">substorms</span>, 80 % of expanded <span class="hlt">substorms</span>, and 99 % of events with coordinated E KL and PC jumps. The low or negative correlation observing in ~10 % of examined <span class="hlt">substorms</span> suggests that the solar wind flow measured by the Advanced Composition Explorer (ACE) spacecraft in the Lagrange point L1 did not encounter the magnetosphere in these cases. Examination of the delay times Δ T in the response of PC index to E KL variations provides the following results: (1) delay times do not depend on separate solar wind parameters, such as solar wind speed V X and interplanetary magnetic field (IMF) B Z component, contrary to general conviction, (2) the Δ T value is best controlled by the E KL field <span class="hlt">growth</span> rate (d E KL/dt), (3) the lower Δ T limit (5-7 min is attained under conditions of the higher E KL <span class="hlt">growth</span> rate, and (4) the PC index provides the possibility to verify the solar wind flow transportation time from ACE position (where the solar wind speed is estimated) to magnetosphere. These results, in combination with data testifying that the <span class="hlt">substorm</span> onsets are related to the PC precursors, demonstrate that the PC index is an adequate ground-based indicator of the solar wind energy incoming into the magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21405807','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21405807"><span><span class="hlt">Growth</span> of a two-<span class="hlt">phase</span> finger in eutectics systems.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Boussinot, G; Hüter, C; Brener, E A</p> <p>2011-02-01</p> <p>We present a theoretical study of the <span class="hlt">growth</span> of a two-<span class="hlt">phase</span> finger in eutectic systems. This pattern was observed experimentally by Akamatsu and Faivre [Phys. Rev. E 61, 3757 (2000)]. We study this two-<span class="hlt">phase</span> finger using a boundary-integral formulation and we complement our investigation by a <span class="hlt">phase</span>-field validation of the stability of the pattern. The deviations from the eutectic temperature and from the eutectic concentration provide two independent control parameters, leading to very different patterns depending on their relative importance. We propose scaling laws for the velocity and the different length scales of the pattern.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=217676','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=217676"><span><span class="hlt">Growth</span> <span class="hlt">Phase</span> dependent gene regulation in Bordetella bronchiseptica</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Bordetellae are Gram negative bacterial respiratory pathogens. Bordetella pertussis, the causative agent of whooping cough, is a human-restricted variant of Bordetella bronchiseptica, which infects a broad range of mammals causing chronic and often asymptomatic infections. <span class="hlt">Growth</span> <span class="hlt">phase</span> dependent gen...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996AnGeo..14..608I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996AnGeo..14..608I"><span>Decay of the Dst field of geomagnetic disturbance after <span class="hlt">substorm</span> onset and its implication to storm-<span class="hlt">substorm</span> relation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Iyemori, T.; Rao, D. R. K.</p> <p>1996-06-01</p> <p>In order to investigate the causal relationship between magnetic storms and <span class="hlt">substorms</span>, variations of the mid-latitude geomagnetic indices, ASY (asymmetric part) and SYM (symmetric part), at <span class="hlt">substorm</span> onsets are examined. <span class="hlt">Substorm</span> onsets are defined by three different phenomena; (1) a rapid increase in the mid-latitude asymmetric-disturbance indices, ASY-D and ASY-H, with a shape of so-called `mid-latitude positive bay\\'; (2) a sharp decrease in the AL index; (3) an onset of Pi2 geomagnetic pulsation. The positive bays are selected using eye inspection and a pattern-matching technique. The 1-min-resolution SYM-H index, which is essentially the same as the hourly Dst index except in terms of the time resolution, does not show any statistically significant development after the onset of <span class="hlt">substorms</span>; it tends to decay after the onset rather than to develop. It is suggested by a simple model calculation that the decay of the magnetospheric tail current after <span class="hlt">substorm</span> onset is responsible for the decay of the Dst field. The relation between the IMF southward turning and the development of the Dst field is re-examined. The results support the idea that the geomagnetic storms and <span class="hlt">substorms</span> are independent processes; that is, the ring-current development is not the result of the frequent occurrence of <span class="hlt">substorms</span>, but that of enhanced convection caused by the large southward IMF. A <span class="hlt">substorm</span> is the process of energy dissipation in the magnetosphere, and its contribution to the storm-time ring-current formation seems to be negligible. The decay of the Dst field after a <span class="hlt">substorm</span> onset is explained by a magnetospheric energy theorem. Acknowledgements. This study is supported in part by the Ministry of Education, Science, Sports, and Culture in Japan, under a Grant-in-Aid for Scientific Research (Category B). Topical Editor D. Alcaydé thanks M. Lockwood and N. J. Fox for their help in evaluating this paper.-> Correspondence to: Y. Kamide-></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007PhRvE..76a1604H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007PhRvE..76a1604H"><span>Crystal <span class="hlt">growth</span> in a three-<span class="hlt">phase</span> system: Diffusion and liquid-liquid <span class="hlt">phase</span> separation in lysozyme crystal <span class="hlt">growth</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Heijna, M. C. R.; van Enckevort, W. J. P.; Vlieg, E.</p> <p>2007-07-01</p> <p>In the <span class="hlt">phase</span> diagram of the protein hen egg-white lysozyme, a region is present in which the lysozyme solution demixes and forms two liquid <span class="hlt">phases</span>. In situ observations by optical microscopy show that the dense liquid droplets dissolve when crystals grow in this system. During this process the demixed liquid region retracts from the crystal surface. The spatial distribution of the dense <span class="hlt">phase</span> droplets present special boundary conditions for Fick’s second law for diffusion. In combination with the cylindrical symmetry provided by the kinetically roughened crystals, this system allows for a full numerical analysis. Using experimental data for setting the boundary conditions, a quasi-steady-state solution for the time-dependent concentration profile was shown to be valid. Comparison of kinetically rough <span class="hlt">growth</span> in a <span class="hlt">phase</span> separated system and in a nonseparated system shows that the <span class="hlt">growth</span> kinetics for a three-<span class="hlt">phase</span> system differs from a two-<span class="hlt">phase</span> system, in that crystals grow more slowly but the duration of <span class="hlt">growth</span> is prolonged.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17677461','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17677461"><span>Crystal <span class="hlt">growth</span> in a three-<span class="hlt">phase</span> system: diffusion and liquid-liquid <span class="hlt">phase</span> separation in lysozyme crystal <span class="hlt">growth</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Heijna, M C R; van Enckevort, W J P; Vlieg, E</p> <p>2007-07-01</p> <p>In the <span class="hlt">phase</span> diagram of the protein hen egg-white lysozyme, a region is present in which the lysozyme solution demixes and forms two liquid <span class="hlt">phases</span>. In situ observations by optical microscopy show that the dense liquid droplets dissolve when crystals grow in this system. During this process the demixed liquid region retracts from the crystal surface. The spatial distribution of the dense <span class="hlt">phase</span> droplets present special boundary conditions for Fick's second law for diffusion. In combination with the cylindrical symmetry provided by the kinetically roughened crystals, this system allows for a full numerical analysis. Using experimental data for setting the boundary conditions, a quasi-steady-state solution for the time-dependent concentration profile was shown to be valid. Comparison of kinetically rough <span class="hlt">growth</span> in a <span class="hlt">phase</span> separated system and in a nonseparated system shows that the <span class="hlt">growth</span> kinetics for a three-<span class="hlt">phase</span> system differs from a two-<span class="hlt">phase</span> system, in that crystals grow more slowly but the duration of <span class="hlt">growth</span> is prolonged.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SuMi...97..132L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SuMi...97..132L"><span>A binary <span class="hlt">phase</span> field crystal study for liquid <span class="hlt">phase</span> heteroepitaxial <span class="hlt">growth</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lu, Yanli; Peng, Yingying; Chen, Zheng</p> <p>2016-09-01</p> <p>The liquid <span class="hlt">phase</span> heteroepitaxial <span class="hlt">growth</span> on predefined crystalline substrate is studied with binary <span class="hlt">phase</span> field crystal (PFC) model. The purpose of this paper focuses on changes of the morphology of epitaxial films, influences of substrate vicinal angles on epitaxial <span class="hlt">growth</span>, characteristics of islands <span class="hlt">growth</span> on both sides of the substrate as well. It is found that the morphology of epitaxial films undergoes the following transitions: layer-by-layer <span class="hlt">growth</span>, islands formation, mismatch dislocations nucleation and climb towards the film-substrate interface. Meanwhile, the density of steps and islands has obviously direct ratio relations with the vicinal angles. Also, preferential regions are found when islands grow on both sides of the substrate. For thinner substrate, the arrangement of islands is more orderly and the appearance of preferential <span class="hlt">growth</span> is more obvious than that of thicker substrate. Also, the existing of preferential regions is much more valid for small substrate vicinal angles in contrast for big substrate vicinal angles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20060011202&hterms=IMF&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DIMF','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20060011202&hterms=IMF&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DIMF"><span>Occurrence frequencies of IMF triggered and nontriggered <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hsu, Tung-Shin; McPherron, Robert L.</p> <p>2003-01-01</p> <p>The occurrence of triggered and nontriggered <span class="hlt">substorm</span> are examined in light of current interest in such issues as <span class="hlt">substorm</span> identification, IMF By variations, and potentially undetected small-scale solar wind perturbation. Global <span class="hlt">substorms</span> are identified using a sudden, persistent decrease in the AL index. The onset of this global expansion is taken to be the time of the Pi 2 burst nearest in time to the beginning of the AL, decrease. IMF triggers were identified both subjectively through visual scanning of the data and automatically with a computer algorithm. Both northward turnings of the IMF Bz and decreases in the amplitude of the By component were considered as possible triggers. Two different solar wind monitors were used in the investigation: IMP-8 in a circular orbit with a distance 12 to approx.35 Re to the Earth-Sun line and ISEE-2 in an elliptical orbit with a distance only 5 to approx.10 Re to the Earth-Sun line. The IMP-8 results show that the triggering probability does not depend on the distance of the monitor from the Earth-Sun line in the range 12-35 Re. The ISEE dataset shows that closer than 12 Re the triggering probability is the same as it is in the IMP-8 data set. Thus there appears to be no dependence of triggering on the location of the monitor provided it is within 35 Re of the Earth. We also demonstrate that including the By component does not significantly increase the probability of <span class="hlt">substorm</span> triggering. Approximately 60% of all <span class="hlt">substorms</span> appear to be triggered. Of the 40% for which we could not identify a trigger, 10% occurred while the IMF was northward. The data suggest that <span class="hlt">substorm</span> onset is a consequence of an internal magnetospheric instability that is highly sensitive to changes in magnetospheric convection induced by a sudden change in the IMF, but that these changes are not always necessary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996JCrGr.163..100T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996JCrGr.163..100T"><span>Liquid <span class="hlt">phase</span> epitaxial <span class="hlt">growth</span> of bismuth based superconductors</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Takemoto, J.; Miyashita, S.; Inoue, T.; Komatsu, H.</p> <p>1996-05-01</p> <p>The liquid <span class="hlt">phase</span> epitaxial <span class="hlt">growth</span> of superconducting films of Bi 2Sr 2CaCu 2O y (2212 <span class="hlt">phase</span>) and Bi 2Sr 2CuO z (2201 <span class="hlt">phase</span>) were carried out on three types of substrates; SrTiO 3, LaAlO 3 and NdGaO 3. Twinning structures of the 2212 <span class="hlt">phase</span> were observed in the films grown on the SrTiO 3 (100) and LaAlO 3 (100) substrates which belong to the cubic crystal system, while nearly twin-free structures were obtained when the film was grown on the NdGaO 3 (001) substrate (orthorhombic system). Atomic force microscopy revealed a 2201 <span class="hlt">phase</span> film with a reasonably flat area (several μm 2) grown on the LaAlO 3 (100) substrate. It was observed that the 2212 <span class="hlt">phase</span> nucleated on the substrate following the Volmer-Weber type mechanism (three-dimensional island <span class="hlt">growth</span> mode). The enlarging processes of the island layers were discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..12010466E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..12010466E"><span><span class="hlt">Substorm</span> simulation: Formation of westward traveling surge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ebihara, Y.; Tanaka, T.</p> <p>2015-12-01</p> <p>Auroral <span class="hlt">substorm</span> expansion is characterized by initial brightening of aurora, followed by a bulge expanding in all directions, and a westward traveling surge (WTS). On the basis of the result obtained by a global magnetohydrodynamic simulation, we propose a scenario for the onset and the subsequent formation of WTS. (1) Near-Earth neutral line releases magnetic tension in the near-Earth plasma sheet to compress plasma and accelerate it earthward. (2) Earthward, perpendicular flow is converted to parallel flow in the near-Earth tail region. (3) Plasma moves earthward parallel to a field line. The plasma pressure is additionally enhanced at off-equator with an expanding slow-mode variation. (4) Flow vorticities coexist near the off-equatorial high-pressure region. Resultant field-aligned current (FAC) is connected to the ionosphere, which may manifest initial brightening. (5) Due to continued earthward flow, the high-plasma pressure region continues to expand to the east and west. (6) The ionospheric conductivity continues to increase in the upward FAC region, and the conductivity gradient becomes steeper. (7) The convergence of the Hall current gives rise to divergent electric field near the steep gradient of the conductivity. (8) Due to the divergent electric field, magnetospheric plasma moves counterclockwise at low altitude (in the Northern Hemisphere). (9) The additional flow vorticity generates a localized upward FAC at low altitudes, which may manifest WTS, and redistributes the ionospheric current and conductivity. Thus, WTS may be maintained in a self-consistent manner, and be a natural consequence of the overflow of the Hall current.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMSM41B1731L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMSM41B1731L"><span><span class="hlt">Substorm</span> onsets at Churchill, Manitoba, inferred from radiowave emission data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Labelle, J. W.; Dansu, H.; Bunch, N. L.; Weatherwax, A. T.; Spanswick, E. L.; Donovan, E. F.</p> <p>2009-12-01</p> <p>Two types of natural auroral radio emissions are detectable at ground level in association with <span class="hlt">substorm</span> onsets: impulsive auroral hiss up to 1 MHz, and medium frequency burst (MFB) at 1.5-4.5 MHz. A thorough survey of MFB observed at Churchill, Manitoba, during 1994-2008 has produced a database of more than 600 events. Riometer and other ground-based data will be checked for a selection of these events to determine what fraction of MFB events is associated with <span class="hlt">substorm</span> onset signatures; preliminary results indicate a high percentage of order 80-100 percent is associated with some <span class="hlt">substorm</span> onset features such as prompt absorption in riometer data or a deep bay in magnetometer data. Furthermore, the large database of Churchill MFB events is expected to include a number of close DMSP conjunctions which will provide space-based data with even closer conjunction than previously achieved. Working from the other direction, MFB occurrences at Churchill have been cross-checked with two existing databases related to <span class="hlt">substorm</span> onsets: the published database of <span class="hlt">substorm</span> onsets determined from IMAGE satellite optical observations [Frey et al., 2004], restricted to those within 400 km of Churchill; and the database of dispersionless injection events inferred from riometer data from Gillam, Manitoba [Spanswick et al., 2007]. Preliminary examination of the data suggests that about 25 percent of the identified <span class="hlt">substorms</span> have corresponding MFB events. This relatively low percentage may result because the onsets identified by the other techniques are based on a somewhat broader/different geographical areas than covered by the single MFB receiver at Churchill. Cross-comparing databases of <span class="hlt">substorm</span> onsets assembled from different types of data will help establish the usefulness of each database. Close DMSP conjunctions will provide in situ data critical to elucidating the generation mechanism of the medium frequency burst. References: Frey H. U., S. B. Mende, V. Angelopoulos, E. F</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19780002212','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19780002212"><span>The Lewis Research Center geomagnetic <span class="hlt">substorm</span> simulation facility</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Berkopec, F. D.; Stevens, N. J.; Sturman, J. C.</p> <p>1977-01-01</p> <p>A simulation facility was established to determine the response of typical spacecraft materials to the geomagnetic <span class="hlt">substorm</span> environment and to evaluate instrumentation that will be used to monitor spacecraft system response to this environment. Space environment conditions simulated include the thermal-vacuum conditions of space, solar simulation, geomagnetic <span class="hlt">substorm</span> electron fluxes and energies, and the low energy plasma environment. Measurements for spacecraft material tests include sample currents, sample surface potentials, and the cumulative number of discharges. Discharge transients are measured by means of current probes and oscilloscopes and are verified by a photomultiplier. Details of this facility and typical operating procedures are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21510087','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21510087"><span>The Cross-field Current Instability for <span class="hlt">Substorm</span> Expansion Onset</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lui, A. T. Y.</p> <p>2011-01-04</p> <p>A challenging problem in the topic of the nonlinear dynamics of the magnetosphere is the physical process responsible for the onset of magnetospheric <span class="hlt">substorms</span>. The early collaboration with Dr. K. Papadopoulos has led to the proposal of a kinetic plasma instability, called the cross-field current instability, as the onset process. This has developed into a full-blown research effort, supplementing the initial theoretical analysis with in-depth data analysis and particle simulations. Several theoretical predictions based on this instability are successfully verified in observations. Data from the present NASA THEMIS mission provide some evidence for its validity. Further investigations for this <span class="hlt">substorm</span> onset process are also 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_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('https://www.osti.gov/scitech/biblio/96513','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/96513"><span>Diurnal double maxima patterns in the F region ionosphere: <span class="hlt">Substorm</span>-related aspects</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pi, X.; Mendillo, M.; Fox, M.W.; Anderson, D.N.</p> <p>1993-08-01</p> <p>Daytime double maxima (twin peaks or bite-outs) in the ionospheric total electron content (TEC) at middle and lower latitudes are found to be related to <span class="hlt">substorm</span> signatures shown in both auroral electrojet and ring current variations. Case studies reveal that during <span class="hlt">substorm</span> onset and recovery <span class="hlt">phases</span>, the penetration of magnetospheric convection electric fields and their subsequent {open_quotes}overshielding{close_quotes} effects may be the major dynamical sources of these events. A theoretical low-latitude ionospheric model is used to simulate the dynamical effects of electric field disturbances on F region electron density and TEC. It is demonstrated that the diurnal double maxima in TEC can be created by a combined effect of E x B drift and altitude-dependent F region chemical loss. The required zonal electric fields are found to have greater penetration efficiency in the early evening sector and their latitudinal requirements appear to change with local time. The time scales for the modeled penetration and overshielding effects are 2-3 hours. Modeling results also show that considerable structuring in the local time variation of the ionospheric {open_quotes}equatorial anomaly{close_quotes} can occur due to the interplay of convection electric field penetration and overshielding effects. The possible cause of the midday bite-out ionospheric disturbances by the meridional winds associated with traveling atmospheric disturbances (TADs) is also addressed in modeling studies, but the specialized nature of the required TADs makes this a less well understood <span class="hlt">substorm</span>-related mechanism. 64 refs., 14 figs., 3 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM41E2537N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM41E2537N"><span>Generation mechanism of L-value dependence of oxygen flux enhancements during <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nakayama, Y.; Ebihara, Y.; Tanaka, T.; Ohtani, S.; Gkioulidou, M.; Takahashi, K.; Kistler, L. M.; Kletzing, C.</p> <p>2015-12-01</p> <p>The Van Allen Probes Helium Oxygen Proton Electron (HOPE) instrument measures charged particles with an energy range from ~eV to ~ tens of keV. The observation shows that the energy flux of the particles increases inside the geosynchronous orbit during <span class="hlt">substorms</span>. For some night-side events around the apogee, the energy flux of O+ ion enhances below ~10 keV at lower L shell, whereas the flux below ~8 keV sharply decreases at higher L shells. This structure of L-energy spectrogram of flux is observed only for the O+ ions. The purpose of this study is to investigate the generation mechanism of the structure by using numerical simulations. We utilized the global MHD simulation developed by Tanaka et al (2010, JGR) to simulate the electric and magnetic fields during <span class="hlt">substorms</span>. We performed test particle simulation under the electric and magnetic fields by applying the same model introduced by Nakayama et al. (2015, JGR). In the test particle simulation each test particle carries the real number of particles in accordance with the Liouville theorem. Using the real number of particles, we reconstructed 6-dimensional <span class="hlt">phase</span> space density and differential flux of O+ ions in the inner magnetosphere. We obtained the following results. (1) Just after the <span class="hlt">substorm</span> onset, the dawn-to-dusk electric field is enhanced to ~ 20 mV/m in the night side tail region at L > 7. (2) The O+ ions are accelerated and transported to the inner region (L > ~5.5) by the large-amplitude electric field. (3) The reconstructed L-energy spectrogram shows a similar structure to the Van Allen Probes observation. (4) The difference in the flux enhancement between at lower L shell and higher L shells is due to two distinct acceleration processes: adiabatic and non-adiabatic. We will discuss the relationship between the particle acceleration and the structure of L-energy spectrogram of flux enhancement in detail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.8939E..05S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.8939E..05S"><span>Differentiating the <span class="hlt">growth</span> <span class="hlt">phases</span> of single bacteria using Raman spectroscopy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Strola, S. A.; Marcoux, P. R.; Schultz, E.; Perenon, R.; Simon, A.-C.; Espagnon, I.; Allier, C. P.; Dinten, J.-M.</p> <p>2014-03-01</p> <p>In this paper we present a longitudinal study of bacteria metabolism performed with a novel Raman spectrometer system. Longitudinal study is possible with our Raman setup since the overall procedure to localize a single bacterium and collect a Raman spectrum lasts only 1 minute. Localization and detection of single bacteria are performed by means of lensfree imaging, whereas Raman signal (from 600 to 3200 cm-1) is collected into a prototype spectrometer that allows high light throughput (HTVS technology, Tornado Spectral System). Accomplishing time-lapse Raman spectrometry during <span class="hlt">growth</span> of bacteria, we observed variation in the net intensities for some band groups, e.g. amides and proteins. The obtained results on two different bacteria species, i.e. Escherichia coli and Bacillus subtilis clearly indicate that <span class="hlt">growth</span> affects the Raman chemical signature. We performed a first analysis to check spectral differences and similarities. It allows distinguishing between lag, exponential and stationary <span class="hlt">growth</span> <span class="hlt">phases</span>. And the assignment of interest bands to vibration modes of covalent bonds enables the monitoring of metabolic changes in bacteria caused by <span class="hlt">growth</span> and aging. Following the spectra analysis, a SVM (support vector machine) classification of the different <span class="hlt">growth</span> <span class="hlt">phases</span> is presented. In sum this longitudinal study by means of a compact and low-cost Raman setup is a proof of principle for routine analysis of bacteria, in a real-time and non-destructive way. Real-time Raman studies on metabolism and viability of bacteria pave the way for future antibiotic susceptibility testing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM44A..04S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM44A..04S"><span>3D kinetic picture of magnetotail explosions and characteristic auroral features prior to and after <span class="hlt">substorm</span> onset</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.; Merkin, V. G.; Motoba, T.</p> <p>2015-12-01</p> <p>Recent findings in theory, observations and 3D particle-in-cell simulations of magnetotail explosions reveal a complex picture of reconnection, buoyancy and flapping motions, which have interesting correlations with the auroral morphology. First, the formation of the tailward Bz gradient as a theoretical prerequisite for tearing, ballooning/interchange and flapping instabilities is consistent with the structure of the pre-onset quiet arc and the associated deep minimum of Bz. Another distinctive pre-onset feature, equatorward extension of the auroral oval in the late <span class="hlt">growth</span> <span class="hlt">phase</span>, is conventionally associated with earthward motion of the inner edge of the plasma sheet. However, if open magnetic flux saturates in the late <span class="hlt">growth</span> <span class="hlt">phase</span>, it may also be treated as a signature of magnetic flux accumulation tailward of the Bz minimum, which is also favorable for the tail plasma sheet instabilities. 3D PIC simulations of similar magnetotail equilibria with a tailward Bz gradient show spontaneous formation of earthward flows led by dipolarization fronts. They are structured in the dawn-dusk direction on the ion inertial scale, consistent with the minimum scales of the observed auroral beads. At the same time, simulations show the formation of a new X-line in the wake of the dipolarization front with no significant spatial modulation in the dawn-dusk direction suggesting smooth profiles of the <span class="hlt">substorm</span> current wedge as well as poleward parts of auroral streamers. Flapping motions, which also grow at the dipolarization front, extend beyond it, up to the new X-line region. To understand auroral manifestations of tail structures in our simulations we investigate the plasma moments at the plasma sheet boundary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005GeoRL..3216104T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005GeoRL..3216104T"><span>Magnetospheric <span class="hlt">substorms</span> are strongly modulated by interplanetary high-speed streams</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tanskanen, E. I.; Slavin, J. A.; Tanskanen, A. J.; Viljanen, A.; Pulkkinen, T. I.; Koskinen, H. E. J.; Pulkkinen, A.; Eastwood, J.</p> <p>2005-08-01</p> <p>The occurrence of <span class="hlt">substorms</span> was examined over a complete 11-year solar cycle, identifying over 5000 <span class="hlt">substorms</span>. It was found that high-speed streams strongly modulate the <span class="hlt">substorm</span> occurrence rate, peak amplitude and ionospheric dissipation in the form of Joule heating and auroral electron precipitation. <span class="hlt">Substorms</span> occurring during the years of frequent interplanetary high-speed streams (1994 and 2003) are 32% more intense, on average, and transfer twice as much magnetic energy to the auroral ionosphere as the <span class="hlt">substorms</span> occurring during the years of few or no high-speed streams (1993, 1995-2002). To characterize and to predict the <span class="hlt">substorm</span> activity we form a new measure, the <span class="hlt">substorm</span> activity parameter Rsu, which we expect to become a powerful tool in analyzing the near-Earth space climate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930046819&hterms=magnitude&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dmagnitude','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930046819&hterms=magnitude&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dmagnitude"><span>A statistical relationship between the geosynchronous magnetic field and <span class="hlt">substorm</span> electrojet magnitude</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lopez, Ramon E.; Von Rosenvinge, Tycho</p> <p>1993-01-01</p> <p>The relationship between the geosynchronous magnetic field variations during <span class="hlt">substorms</span> measured by GOES 5 and the auroral electroject as measured by AE and Poste de la Baleine is examined. It is found that the more taillike the field prior to the local onset, the greater the dipolarization of the field during the <span class="hlt">substorm</span>. The greater the deviation of the field from a dipolar configuration, the larger the change in AE during the event. It is inferred that stronger cross-tail currents prior to the <span class="hlt">substorm</span> are associated with larger <span class="hlt">substorm</span>-associated westward electrojets and thus more intense <span class="hlt">substorms</span>. Since the westward electroject is the ionospheric leg of the <span class="hlt">substorm</span> current wedge, it is inferred that the <span class="hlt">substorm</span>-associated westward electrojet is drawn from the near-earth region. Most of the current diversion is found to occur in the near-earth magnetotail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930046819&hterms=Ramon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D40%26Ntt%3DRamon','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930046819&hterms=Ramon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D40%26Ntt%3DRamon"><span>A statistical relationship between the geosynchronous magnetic field and <span class="hlt">substorm</span> electrojet magnitude</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lopez, Ramon E.; Von Rosenvinge, Tycho</p> <p>1993-01-01</p> <p>The relationship between the geosynchronous magnetic field variations during <span class="hlt">substorms</span> measured by GOES 5 and the auroral electroject as measured by AE and Poste de la Baleine is examined. It is found that the more taillike the field prior to the local onset, the greater the dipolarization of the field during the <span class="hlt">substorm</span>. The greater the deviation of the field from a dipolar configuration, the larger the change in AE during the event. It is inferred that stronger cross-tail currents prior to the <span class="hlt">substorm</span> are associated with larger <span class="hlt">substorm</span>-associated westward electrojets and thus more intense <span class="hlt">substorms</span>. Since the westward electroject is the ionospheric leg of the <span class="hlt">substorm</span> current wedge, it is inferred that the <span class="hlt">substorm</span>-associated westward electrojet is drawn from the near-earth region. Most of the current diversion is found to occur in the near-earth magnetotail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AdSpR..47..702T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AdSpR..47..702T"><span>Saw-tooth <span class="hlt">substorms</span>: Inconsistency of repetitive bay-like magnetic disturbances with behavior of aurora</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Troshichev, O.; Stauning, P.; Liou, K.; Reeves, G.</p> <p>2011-02-01</p> <p>The relationships between the magnetic disturbance onsets, aurora dynamics and particles injections at the geostationary orbit have been analyzed in detail for 25 sawtooth <span class="hlt">substorms</span>. It is shown that inconsistency between the above signatures of the <span class="hlt">substorms</span> onset is typical of the powerful sawtooth <span class="hlt">substorms</span>, unlike the isolated (“classical”) magnetospheric <span class="hlt">substorms</span>. The distinguishing feature of the aurora in case of saw-tooth <span class="hlt">substorms</span> is permanently high level of auroral activity irrespective of the magnetic disturbance onsets and the double oval structure of the aurora display. The close relationship between the aurora behavior and the particle injections at geostationary orbit is also broken. The conclusion is made, that the classical concept of the <span class="hlt">substorm</span> development, put forward by Akasofu (1964) for isolated <span class="hlt">substorms</span>, is not workable in cases of the sawtooth disturbances, when the powerful solar wind energy pumping into the magnetosphere provides a permanent powerful aurora particle precipitation into the auroral zone.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PhyE...94..178L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PhyE...94..178L"><span>Influences of misfit strains on liquid <span class="hlt">phase</span> heteroepitaxial <span class="hlt">growth</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lu, Yanli; Peng, Yingying; Yu, Genggeng; Chen, Zheng</p> <p>2017-10-01</p> <p>Influences of misfit strains with different signs on liquid <span class="hlt">phase</span> heteroepitaxial <span class="hlt">growth</span> are studied by binary <span class="hlt">phase</span> field crystal model. It is amazing to find that double islands are formed because of lateral and vertical separation. The morphological evolution of epitaxial layer depends on signs of misfit strains. The maximum atomic layer thickness of double islands under negative misfit strain is larger than that of under positive misfit strain at the same evolutional time, and size differences between light and dark islands is much smaller under negative misfit strain than that of under positive misfit strain. In addition, concentration field and density field approximately have similar variational law along x direction under the same misfit strain but show opposite variational trend under misfit strains with different signs. Generally, free energy of epitaxial <span class="hlt">growth</span> systems keeps similar variational trend under misfit strains with different signs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004PhDT.......157M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004PhDT.......157M"><span>Nucleation and <span class="hlt">growth</span> studies of crystalline carbon <span class="hlt">phases</span> at nanoscale</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mani, Radhika C.</p> <p></p> <p>Understanding the nucleation and early stage <span class="hlt">growth</span> of crystals from the vapor <span class="hlt">phase</span> is important for realizing large-area single-crystal quality films, controlled synthesis of nanocrystals, and the possible discovery of new <span class="hlt">phases</span> of materials. Carbon provides the most interesting system because all its known crystalline <span class="hlt">phases</span> (diamond, graphite and carbon nanotubes) are technologically important materials. Hence, this dissertation is focused on studying the nucleation and <span class="hlt">growth</span> of carbon <span class="hlt">phases</span> synthesized from the vapor <span class="hlt">phase</span>. Nucleation experiments were performed in a microwave plasma chemical vapor deposition (CVD) reactor, and the resulting carbon nanocrystals were analyzed primarily using electron nanodiffraction and Raman spectroscopy. These studies led to the discovery of two new crystalline <span class="hlt">phases</span> of sp 3 carbon other than diamond: face-centered and body-centered cubic carbon. Nanodiffraction results revealed possible hydrogen substitution into diamond-cubic lattices, indicating that these new <span class="hlt">phases</span> probably act as intermediates in diamond nucleation. Nucleation experiments also led to the discovery of two new morphologies for sp2 carbon: nanocrystals of graphite and tapered, hollow 1-D structures termed here as "carbon nanopipettes". A Kinetic Monte Carlo (KMC) algorithm was developed to simulate the <span class="hlt">growth</span> of individual diamond crystals from the vapor <span class="hlt">phase</span>, starting with small clusters of carbon atoms (or seeds). Specifically, KMC simulations were used to distinguish the kinetic rules that give rise to a star-shaped decahedral morphology compared to decahedral crystals. KMC simulations revealed that slow adsorption on the {111} step-propagation sites compared to kink sites leads to star-decahedral crystals, and higher adsorption leads to decahedral crystals. Since the surfaces of the nanocrystals of graphite and nanopipettes were expected to be composed primarily of edge-plane sites, the electrochemical behavior of both these materials were</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1991GMS....64..449K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1991GMS....64..449K"><span>A nonlinear dynamic analogue model of <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Klimas, A. J.; Baker, D. N.; Roberts, D. A.; Fairfield, D. H.; Büchner, J.</p> <p></p> <p>Linear prediction filter studies have shown that the magnetospheric response to energy transfer from the solar wind contains both directly driven and unloading components. These studies have also shown that the magnetospheric response is significantly nonlinear and, thus, the linear prediction filtering technique and other correlative techniques which assume a linear magnetospheric response cannot give a complete deacription of that response. Here, the solar wind-magnetosphere interaction is discussed within the framework of deterministic nonlinear dynamics. An earlier dripping faucet mechanical analogue to the magnetosphere is first reviewed and then the plasma physical counterpart to the mechanical model is constructed. A Faraday loop in the magnetotail is considered and the relationship of electric potentials on the loop to changes in the magnetic flux threading the loop is developed. This approach leads to a model of geomagnetic activity which is similar to the earlier mechanical model but described in terms of the geometry and plasma contents of the magnetotail. This Faraday loop response model contains analogues to both the directly driven and the storage-release magnetospheric responses and it includes, in a fundamental way, the inherent nonlinearity of the solar wind-magnetosphere system. It can be chancterized as a nonlinear, damped harmonic oscillator that is driven by the loading-unloading <span class="hlt">substorm</span> cycle. The model is able to explain many of the features of the linear prediction filter results. In particular, at low geomagnetic activity levels the model exbibits the "regular dripping" response which provides an explanation for the unloading component at 1 hour lag in the linear prediction filters. Further, the model suggests that the disappearance of the unloading component in the linear prediction filters at high geomagnetic activity levels is due to a chaotic transition beyond which the loading-unloading mechanism becomes aperiodic. The model predicts</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSM23A4173N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSM23A4173N"><span>Rapid enhancement of energetic oxygen ions in the inner magnetosphere during <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nakayama, Y.; Ebihara, Y.; Tanaka, T.</p> <p>2014-12-01</p> <p>Satellite observations show that energetic (>100 keV) O+ ions are rapidly increased in the inner magnetosphere during <span class="hlt">substorms</span>. The ultimate source of O+ ions is the Earth's ionosphere, so that O+ ions must be accelerated from ~eV to 100s keV somewhere in the magnetosphere. A fundamental question still arise regarding why O+ ions are accelerated and transported to the inner magnetosphere. We simulated <span class="hlt">substorms</span> under two different solar wind conditions by using the global MHD simulation developed by Tanaka et al. (2010, JGR). The solar wind speed is set to be 372 km/s for Case I, and 500 km/s for Case II. In both cases, the MHD simulation result shows that the dawn to dusk electric field is enhanced in the night side tail region at >7 Re just after the <span class="hlt">substorm</span> onset. In particular, the electric field in the inner region (~7 Re) is highly enhanced by the tension force because of relatively strong magnetic field together with curved field lines. The strongest electric field takes place near the region where the plasma pressure is high. We performed test particle simulation under the electric and magnetic fields for Cases I and II. O+ ions are released from two planes located at ±2 Re in the Z direction in the tail region. O+ ions released at the two planes represent outflowing stream of O+ ions escaping from the Earth. The distribution function at the planes is assumed to be drifting Kappa distribution with temperature of 10 eV, the density of 105 m-3, and the parallel velocity given by the MHD simulation. In total, around a billion of particles are traced. Each test particle carries the real number of particles in accordance with the Liouville theorem. After tracing particles, we reconstructed 6-dimensional <span class="hlt">phase</span> space density of O+ ions. We obtained the following results. (1) Just after <span class="hlt">substorm</span> onset, the differential flux of O+ ions is almost simultaneously enhanced in the region where the electric field is strong. (2) The kinetic energy increases rapidly to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JGRA..117.4223Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JGRA..117.4223Y"><span>Large-scale current systems and ground magnetic disturbance during deep <span class="hlt">substorm</span> injections</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, J.; Toffoletto, F. R.; Wolf, R. A.; Sazykin, S.; Ontiveros, P. A.; Weygand, J. M.</p> <p>2012-04-01</p> <p>We present a detailed analysis of the large-scale current systems and their effects on the ground magnetic field disturbance for an idealized <span class="hlt">substorm</span> event simulated with the equilibrium version of the Rice Convection Model. The objective of this study is to evaluate how well the bubble-injection picture can account for some classic features of the <span class="hlt">substorm</span> expansion <span class="hlt">phase</span>. The entropy depletion inside the bubble is intentionally designed to be so severe that it can penetrate deep into geosynchronous orbit. The results are summarized as follows: (1) Both the region-1-sense and region-2-sense field-aligned currents (FACs) intensify substantially. The former resembles the <span class="hlt">substorm</span> current wedge and flows along the eastern and western edges of the bubble. The latter is connected to the enhanced partial ring current in the magnetosphere associated with a dipolarization front earthward of the bubble. In the ionosphere, these two pairs of FACs are mostly interconnected via Pedersen currents. (2) The horizontal ionospheric currents show a significant westward electrojet peaked at the equatorward edge of the footprint of the bubble. The estimated ground magnetic disturbance is consistent with the typical features at various locations relative to the center of the westward electrojet. (3) A prominent Harang-reversal-like boundary is seen in both ground ΔH disturbance and plasma flow pattern, appearing in the westward portion of the equatorward edge of the bubble footprint, with a latitudinal extent of ˜5° and a longitudinal extent of the half width of the bubble. (4) The dramatic dipolarization inside the bubble causes the ionospheric map of the inner plasma sheet to exhibit a bulge-like structure, which may be related to auroral poleward expansion. (5) The remarkable appearance of the westward electrojet, Harang-reversal-like boundary and poleward expansion starts when the bubble reaches the magnetic transition region from tail-like to dipole-like configuration. We</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1475634','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1475634"><span>Special <span class="hlt">phase</span> transformation and crystal <span class="hlt">growth</span> pathways observed in nanoparticles†</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Gilbert, Benjamin; Zhang, Hengzhong; Huang, Feng; Finnegan, Michael P; Waychunas, Glenn A; Banfield, Jillian F</p> <p>2003-01-01</p> <p><span class="hlt">Phase</span> transformation and crystal <span class="hlt">growth</span> in nanoparticles may happen via mechanisms distinct from those in bulk materials. We combine experimental studies of as-synthesized and hydrothermally coarsened titania (TiO2) and zinc sulfide (ZnS) with thermodynamic analysis, kinetic modeling and molecular dynamics (MD) simulations. The samples were characterized by transmission electron microscopy, X-ray diffraction, synchrotron X-ray absorption and scattering, and UV-vis spectroscopy. At low temperatures, <span class="hlt">phase</span> transformation in titania nanoparticles occurs predominantly via interface nucleation at particle–particle contacts. Coarsening and crystal <span class="hlt">growth</span> of titania nanoparticles can be described using the Smoluchowski equation. Oriented attachment-based crystal <span class="hlt">growth</span> was common in both hydrothermal solutions and under dry conditions. MD simulations predict large structural perturbations within very fine particles, and are consistent with experimental results showing that ligand binding and change in aggregation state can cause <span class="hlt">phase</span> transformation without particle coarsening. Such phenomena affect surface reactivity, thus may have important roles in geochemical cycling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20030056681','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20030056681"><span>Distinct Magnetospheric Responses to Southward IMF in Two <span class="hlt">Substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>El-Alaoui, Mostafa; Ashour-Abdalla, M.; Richard, R. L.; Frank, L. A.; Paterson, W. R.; Sigwarth, J. B.</p> <p>2003-01-01</p> <p>Solar wind plasma parameters and the Interplanetary Magnetic Field (IMF) observed by the WIND spacecraft upstream of the bow shock were used as input to magnetohydrodynamic (MHD) simulations of two <span class="hlt">substorm</span> events. The power deposited into the ionosphere due to electron precipitation was calculated both from VIS observations and from the simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000PhRvE..62.2547D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000PhRvE..62.2547D"><span>Analysis of a ``<span class="hlt">phase</span> transition'' from tumor <span class="hlt">growth</span> to latency</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Delsanto, P. P.; Romano, A.; Scalerandi, M.; Pescarmona, G. P.</p> <p>2000-08-01</p> <p>A mathematical model, based on the local interaction simulation approach, is developed in order to allow simulations of the spatiotemporal evolution of neoplasies. The model consists of a set of rules, which govern the interaction of cancerous cells among themselves and in competition with other cell populations for the acquisition of essential nutrients. As a result of small variations in the basic parameters, it leads to four different outcomes: indefinite <span class="hlt">growth</span>, metastasis, latency, and complete regression. In the present contribution a detailed analysis of the dormant <span class="hlt">phase</span> is carried on and the critical parameters for the transition to other <span class="hlt">phases</span> are computed. Interesting chaotic behaviors can also be observed, with different attractors in the parameters space. Interest in the latency <span class="hlt">phase</span> has been aroused by therapeutical strategies aiming to reduce a growing tumor to dormancy. The effect of such strategies may be simulated with our approach.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1182531','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1182531"><span>Nanowire <span class="hlt">growth</span> by an electron beam induced massive <span class="hlt">phase</span> transformation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sood, Shantanu; Kisslinger, Kim; Gouma, Perena</p> <p>2014-11-15</p> <p>Tungsten trioxide nanowires of a high aspect ratio have been synthesized in-situ in a TEM under an electron beam of current density 14A/cm² due to a massive polymorphic reaction. Sol-gel processed pseudocubic <span class="hlt">phase</span> nanocrystals of tungsten trioxide were seen to rapidly transform to one dimensional monoclinic <span class="hlt">phase</span> configurations, and this reaction was independent of the substrate on which the material was deposited. The mechanism of the self-catalyzed polymorphic transition and accompanying radical shape change is a typical characteristic of metastable to stable <span class="hlt">phase</span> transformations in nanostructured polymorphic metal oxides. A heuristic model is used to confirm the metastable to stable <span class="hlt">growth</span> mechanism. The findings are important to the control electron beam deposition of nanowires for functional applications starting from colloidal precursors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1182531-nanowire-growth-electron-beam-induced-massive-phase-transformation','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1182531-nanowire-growth-electron-beam-induced-massive-phase-transformation"><span>Nanowire <span class="hlt">growth</span> by an electron beam induced massive <span class="hlt">phase</span> transformation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Sood, Shantanu; Kisslinger, Kim; Gouma, Perena</p> <p>2014-11-15</p> <p>Tungsten trioxide nanowires of a high aspect ratio have been synthesized in-situ in a TEM under an electron beam of current density 14A/cm² due to a massive polymorphic reaction. Sol-gel processed pseudocubic <span class="hlt">phase</span> nanocrystals of tungsten trioxide were seen to rapidly transform to one dimensional monoclinic <span class="hlt">phase</span> configurations, and this reaction was independent of the substrate on which the material was deposited. The mechanism of the self-catalyzed polymorphic transition and accompanying radical shape change is a typical characteristic of metastable to stable <span class="hlt">phase</span> transformations in nanostructured polymorphic metal oxides. A heuristic model is used to confirm the metastable to stablemore » <span class="hlt">growth</span> mechanism. The findings are important to the control electron beam deposition of nanowires for functional applications starting from colloidal precursors.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhDT.......213A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhDT.......213A"><span><span class="hlt">Phase</span> field modeling of grain <span class="hlt">growth</span> in porous polycrystalline solids</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ahmed, Karim E.</p> <p></p> <p>The concurrent evolution of grain size and porosity in porous polycrystalline solids is a technically important problem. All the physical properties of such materials depend strongly on pore fraction and pore and grain sizes and distributions. Theoretical models for the pore-grain boundary interactions during grain <span class="hlt">growth</span> usually employ restrictive, unrealistic assumptions on the pore and grain shapes and motions to render the problem tractable. However, these assumptions limit the models to be only of qualitative nature and hence cannot be used for predictions. This has motivated us to develop a novel <span class="hlt">phase</span> field model to investigate the process of grain <span class="hlt">growth</span> in porous polycrystalline solids. Based on a dynamical system of coupled Cahn-Hilliard and All en-Cahn equations, the model couples the curvature-driven grain boundary motion and the migration of pores via surface diffusion. As such, the model accounts for all possible interactions between the pore and grain boundary, which highly influence the grain <span class="hlt">growth</span> kinetics. Through a formal asymptotic analysis, the current work demonstrates that the <span class="hlt">phase</span> field model recovers the corresponding sharp-interface dynamics of the co-evolution of grain boundaries and pores; this analysis also fixes the model kinetic parameters in terms of real materials properties. The model was used to investigate the effect of porosity on the kinetics of grain <span class="hlt">growth</span> in UO2 and CeO2 in 2D and 3D. It is shown that the model captures the phenomenon of pore breakaway often observed in experiments. Pores on three- and four- grain junctions were found to transform to edge pores (pores on two-grain junction) before complete separation. The simulations demonstrated that inhomogeneous distribution of pores and pore breakaway lead to abnormal grain <span class="hlt">growth</span>. The simulations also showed that grain <span class="hlt">growth</span> kinetics in these materials changes from boundary-controlled to pore-controlled as the amount of porosity increases. The kinetic <span class="hlt">growth</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSM12A..06B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSM12A..06B"><span>The Role of <span class="hlt">Substorms</span> in Radiation Belt Particle Enhancements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baker, D. N.</p> <p>2014-12-01</p> <p>Observational and numerical modeling evidence demonstrates that magnetospheric <span class="hlt">substorms</span> are a coherent set of processes within the coupled near-Earth system. This supports the view that <span class="hlt">substorms</span> are a global configurational instability. The magnetosphere progresses through a specific sequence of energy-loading and stress-developing states until the entire system suddenly reconfigures. Related long-term studies of relativistic electron fluxes in the Earth's magnetosphere have revealed many of their temporal occurrence characteristics and their relationships to solar wind drivers. Early work showed the obvious and powerful role played by solar wind speed in producing subsequent high-energy electron enhancements. More recent work has also pointed out the key role that the north-south component of the IMF plays: In order to observe major relativistic electron enhancements, there must typically be a significant interval of southward IMF along with a period of high (VSW≥500 km/s) solar wind speed. This has led to the view that enhancements in geomagnetic activity (i.e., magnetospheric <span class="hlt">substorms</span>) are normally a key first step in the acceleration of radiation belt electrons to high energies. A second step is suggested to be a period of powerful low-frequency waves that is closely related to high values of VSW or higher frequency ("chorus") waves that rapidly heat and accelerate electrons. Hence, <span class="hlt">substorms</span> provide a "seed" population, while high-speed solar wind drives the acceleration to relativistic energies in this two-step geomagnetic activity scenario. This picture seems to apply to most storms examined whether associated with high-speed streams or with CME-related events. In this talk, we address the <span class="hlt">substorm</span> relationships as they pertain to high-energy electron acceleration and transport. We also discuss various models of electron energization that have recently been advanced. We present remarkable new results from the Van Allen Probes (Radiation Belt Storm</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://hdl.handle.net/2060/19980018999','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980018999"><span>Force Balance and <span class="hlt">Substorm</span> Effects in the Magnetotail</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kaufmann, Richard L.; Larson, Douglas J.; Kontodinas, Ioannis D.; Ball, Bryan M.</p> <p>1997-01-01</p> <p>A model of the quiet time middle magnetotail is developed using a consistent orbit tracing technique. The momentum equation is used to calculate geocentric solar magnetospheric components of the particle and electromagnetic forces throughout the current sheet. Ions generate the dominant x and z force components. Electron and ion forces almost cancel in the y direction because the two species drift earthward at comparable speeds. The force viewpoint is applied to a study of some <span class="hlt">substorm</span> processes. Generation of the rapid flows seen during <span class="hlt">substorm</span> injection and bursty bulk flow events implies substantial force imbalances. The formation of a <span class="hlt">substorm</span> diversion loop is one cause of changes in the magnetic field and therefore in the electromagnetic force. It is found that larger forces are produced when the cross-tail current is diverted to the ionosphere than would be produced if the entire tail current system simply decreased. Plasma is accelerated while the forces are unbalanced resulting in field lines within a diversion loop becoming more dipolar. Field lines become more stretched and the plasma sheet becomes thinner outside a diversion loop. Mechanisms that require thin current sheets to produce current disruption then can create additional diversion loops in the newly thinned regions. This process may be important during multiple expansion <span class="hlt">substorms</span> and in differentiating pseudoexpansions from full <span class="hlt">substorms</span>. It is found that the tail field model used here can be generated by a variety of particle distribution functions. However, for a given energy distribution the mixture of particle mirror or reflection points is constrained by the consistency requirement. The study of uniqueness also leads to the development of a technique to select guiding center electrons that will produce charge neutrality all along a flux tube containing nonguiding center ions without the imposition of a parallel electric field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19790046450&hterms=Electromagnetic+spectrum&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DElectromagnetic%2Bspectrum','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19790046450&hterms=Electromagnetic+spectrum&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DElectromagnetic%2Bspectrum"><span>Electromagnetic and electrostatic emissions at the cusp-magnetosphere interface during <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Curtis, S. A.; Fairfield, D. H.; Wu, C. S.</p> <p>1979-01-01</p> <p>Strongly peaked electrostatic emissions near 10.0 kHz and electromagnetic emissions near 0.56 kHz have been observed by the VLF wave detector on board Imp 6 on crossings from the earth's magnetosphere into the polar cusp during the occurrence of large magnetospheric <span class="hlt">substorms</span>. The electrostatic emissions were observed to be closely confined to the cusp-magnetosphere interface. The electromagnetic emissions were of somewhat broader spatial extent and were seen on higher-latitude field lines within the cusp. Using these plasma wave observations and additional information provided by plasma, magnetometer and particle measurements made simultaneously on Imp 6, theories are constructed to explain each of the two classes of emission. The electromagnetic waves are modeled as whistlers, and the electrostatic waves as electron-cyclotron harmonics. The resulting <span class="hlt">growth</span> rates predict power spectra similar to those observed for both emission classes. The electrostatic waves may play a significant role via enhanced diffusion in the relaxation of the sharp <span class="hlt">substorm</span> time cusp-magnetosphere boundary to a more diffuse quiet time boundary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19790046450&hterms=spectrum+electromagnetic&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dspectrum%2Belectromagnetic','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19790046450&hterms=spectrum+electromagnetic&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dspectrum%2Belectromagnetic"><span>Electromagnetic and electrostatic emissions at the cusp-magnetosphere interface during <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Curtis, S. A.; Fairfield, D. H.; Wu, C. S.</p> <p>1979-01-01</p> <p>Strongly peaked electrostatic emissions near 10.0 kHz and electromagnetic emissions near 0.56 kHz have been observed by the VLF wave detector on board Imp 6 on crossings from the earth's magnetosphere into the polar cusp during the occurrence of large magnetospheric <span class="hlt">substorms</span>. The electrostatic emissions were observed to be closely confined to the cusp-magnetosphere interface. The electromagnetic emissions were of somewhat broader spatial extent and were seen on higher-latitude field lines within the cusp. Using these plasma wave observations and additional information provided by plasma, magnetometer and particle measurements made simultaneously on Imp 6, theories are constructed to explain each of the two classes of emission. The electromagnetic waves are modeled as whistlers, and the electrostatic waves as electron-cyclotron harmonics. The resulting <span class="hlt">growth</span> rates predict power spectra similar to those observed for both emission classes. The electrostatic waves may play a significant role via enhanced diffusion in the relaxation of the sharp <span class="hlt">substorm</span> time cusp-magnetosphere boundary to a more diffuse quiet time boundary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990080077&hterms=McCarthy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D90%26Ntt%3DMcCarthy','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990080077&hterms=McCarthy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D90%26Ntt%3DMcCarthy"><span>Understanding <span class="hlt">Substorms</span> from the Auroral Ionosphere to the Distant Plasma Sheet</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Parks, G. K.; Brittnacher, M.; Chen, L.; Chua, D.; Elsen, R.; Fillingim, M.; McCarthy, M.; Wilber, M.; Germany, G.; Spann, J.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_19990080077'); toggleEditAbsImage('author_19990080077_show'); toggleEditAbsImage('author_19990080077_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_19990080077_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_19990080077_hide"></p> <p>1998-01-01</p> <p>The global polar UVI images have been correlated with observations from the ground, ionosphere, geomagnetic tail between 10-20 earth radii and the interplanetary space. One of the objectives of our study is to better understand the connection among many complex phenomena occurring close to Earth and those in the near--earth plasma sheet. We have examined the details of how the auroral and polar cap boundaries at different local times behave in relation to variations occurring in the solar wind, ionosphere and plasma sheet during <span class="hlt">substorms</span>. We have also compared locations of boundaries deduced from images to electron flux "boundaries" observed by polar orbiting spacecraft. Our results indicate that the ionospheric dynamics is important and polar cap and auroral oval boundaries expand and contract in a complicated but systematic way. These variations are correlated to solar wind parameters and <span class="hlt">growth</span> and recovery phenomena in the plasma sheet. These results can be interpreted in terms of directly driven and/or unloading <span class="hlt">substorm</span> processes.</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>Association of an auroral surge with plasma sheet recovery and the retreat of the <span class="hlt">substorm</span> 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 <span class="hlt">substorm</span>, 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 plasma sheet recovery was occasioned by the arrival at ISEE 1,2 of a westward traveling wave of plasma sheet thickening, the wave itself being formed by westward progression of the <span class="hlt">substorm</span> 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 plasma velocity shear in the plasma sheet 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 <span class="hlt">substorm</span> expansive <span class="hlt">phase</span> are manifestations of (and are driven by) velocity shear in the plasma sheet near the ends of the extending <span class="hlt">substorm</span> neutral line.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970027652','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970027652"><span>Geotail Measurements Compared with the Motions of High-Latitude Auroral Boundaries during Two <span class="hlt">Substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Maynard, N. C.; Burke, W. J.; Erickson, G. M.; Nakamura, M.; Mukai, T.; Kokubun, S.; Yamamoto, T.; Jacobsen, B.; Egeland, A.; Samson, J. C.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_19970027652'); toggleEditAbsImage('author_19970027652_show'); toggleEditAbsImage('author_19970027652_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_19970027652_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_19970027652_hide"></p> <p>1997-01-01</p> <p>Geotail plasma and field measurements at -95 R(sub E) are compared with extensive ground-based, near-Earth, and geosynchronous measurements to study relationships between auroral activity and magnetotail dynamics during the expansion <span class="hlt">phases</span> of two <span class="hlt">substorms</span>. The studied intervals are representative of intermittent, moderate activity. The behavior of the aurora and the observed effects at Geotail for both events are harmonized by the concept of the activation of near-Earth X lines (NEXL) after <span class="hlt">substorm</span> onsets, with subsequent discharges of one or more plasmoids down the magnetotail. The plasmoids must be viewed as three-dimensional structures which are spatially limited in the dawn-dusk direction. Also, reconnection at the NEXL must proceed at variable rates on closed magnetic field lines for significant times before beginning to reconnect lobe flux. This implies that the plasma sheet in the near-Earth magnetotail is relatively thick in comparison with an embedded current sheet and that both the NEXL and distant X line can be active simultaneously. Until reconnection at the NEXL engages lobe flux, the distant X line maintains control of the poleward auroral boundary. If the NEXL remains active after reaching the lobe, the auroral boundary can move poleward explosively. The dynamics of high-latitude aurora in the midnight region thus provides a means for monitoring these processes and indicating when significant lobe flux reconnects at the NEXL.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUSMSM41A..03T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUSMSM41A..03T"><span><span class="hlt">Substorm</span> and High Speed Stream Observations During Solar Cyles 22 and 23</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tanskanen, E. I.; Slavin, J. A.; Tanskanen, A. J.; Viljanen, A.; Pulkkinen, T. I.; Koskinen, H. E.; Huttunen, K. E.</p> <p>2005-05-01</p> <p>Magnetic measurements from the MIRACLE network are used to identify <span class="hlt">substorms</span> during solar cycles 22 and 23, from 1993 to 2004. For the first time <span class="hlt">substorm</span> activity is examined over a complete solar cycle. In this study more than 5000 <span class="hlt">substorms</span> are identified and their interplanetary drivers are examined. A new parameter called <span class="hlt">substorm</span> number Rsu is formed based on (monthly) averages of <span class="hlt">substorm</span> peak amplitudes. The <span class="hlt">substorm</span> number measures magnetic activity of the Earth's magnetosphere in a way analogous to how sunspot number Rz estimates the level of Sun's magnetic activity. Analysis of WIND, ACE and SOHO interplanetary measurements indicate that high speed streams (HSS, with Sun-to-Earth velocities over 700 km/s) are the main drivers of the terrestrial <span class="hlt">substorms</span>. The <span class="hlt">substorm</span> number peaked in 1994-1995 and in 2003-2004 (at 3-4 years after the sunspot maximum), which is when the high speed streams occurred repeatedly every 27 days. During the years of repeated HSSs, <span class="hlt">substorms</span> occurred more frequently, were more intense, and carried more magnetic energy to the auroral ionosphere, compared to the <span class="hlt">substorms</span> existing during non-HSS intervals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006cosp...36.1335G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006cosp...36.1335G"><span>Geomagnetic Storm and <span class="hlt">Substorm</span> effect on the total electron content using GPS at subauroral latitudes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gomez, L.; Sabione, J. I.; van Zele, M. A.; Meza, A. M.; Brunini, C.</p> <p></p> <p>The aim of this work is to characterize the ionospheric electron content variability during a geomagnetic storm and <span class="hlt">substorms</span> during it This study is based on the vertical total electron content VTEC computed from global positioning system GPS GPS stations located at sub-auroral latitudes are taken into account for analyzing the signatures of the current wedge formed during the <span class="hlt">substorm</span> expansion <span class="hlt">phase</span> The study is focused on the geomagnetic storm befallen on April 6 and 7 2000 near the equinox Because our study is based on tying the geomagnetic disturbances with the variability of VTEC in local time the GPS stations are located at different geographic longitude The main results are a when the geomagnetic storm starts between pre-midnight and dawn a minimum of VTEC is recorded lasting all the long day ionospheric storm negative <span class="hlt">phase</span> also the nighttime electron content may decrease below the corresponding for quiet days but near the 60z of latitude the ionization polar tongue can be observed at noon superimposed to the negative <span class="hlt">phase</span> b the VTEC computed by GPS station placed lower than 50o recorded a positive <span class="hlt">phase</span> when the geomagnetic storm starts between dawn and noon or a dusk effect if it starts at noon while those located between 50o and 60o show a sudden increase and later sudden decrease to nocturnal values c when it starts between afternoon and sunset the ionospheric negative <span class="hlt">phase</span> is recorded during the next day and if the GPS station are located at higher latitude than 50o the VTEC representation shows the nocturnal end of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997SPIE.3111..429C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997SPIE.3111..429C"><span>Extraordinary <span class="hlt">growth</span> <span class="hlt">phases</span> of nanobacteria isolated from mammalian blood</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ciftcioglu, Neva; Pelttari, Alpo; Kajander, E. Olavi</p> <p>1997-07-01</p> <p>Nanobacteria, novel sterile-filterable coccoid bacteria inhabiting mammalian blood and blood products, have different <span class="hlt">growth</span> <span class="hlt">phases</span> depending on the culture conditions. These minute organisms produce biogenic apatite as a part of their envelope. This becomes thicker as the cultures age, rendering them visible in microscopy and resistant to harsh conditions. Mineral deposits were not formed without live nanobacteria. Apatite formation was faster and more voluminous in serum-free (SF) medium, and within a week, several micrometer thick `castles' formed around each nanobacteria. These formations were firmly attached to the culture plates. Nanobacteria multiplied inside these thick layers by turning into D-shaped forms 2 - 3 micrometers in size. After a longer culture period, tens of them could be observed inside a common stony shelter. The apatite shelters had a hollow interior compartment occupied by the organisms as evidenced by SEM and TEM. Supplementing the culture medium with a milk <span class="hlt">growth</span>-factor product, caused the castles to grow bigger by budding. These formations finally lost their mineral layer, and released typical small coccoid nanobacteria. When SF cultures were supplemented with sterile serum, mobile D-shaped nanobacteria together with small `elementary particles' 50 - 100 nm in size were found. Negative results in standard sterility testing, positivity in immunofluorescence staining and ELISA tests with nanobacteria-specific monoclonal antibodies, and 98% identity of 16S rRNA gene sequences proved that all of these unique creates are nanobacterial <span class="hlt">growth</span> <span class="hlt">phases</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhDT.......211G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhDT.......211G"><span>Alloy <span class="hlt">Phase</span> Diagrams for III-P Semiconductor Crystal <span class="hlt">Growth</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gennett, Adam</p> <p></p> <p>Bulk crystals of III-V ternary and quaternary semiconductors with tunable band gaps and lattice constants are attractive for numerous electronic and optoelectronic applications. In particular, the ternary GaxIn 1-xP has a band gap range of 1.351 - 2.261 eV, which corresponds to wavelengths in the near infrared to green range of the electromagnetic spectrum, and lattice constant ranging of 5.4512 - 5.8688 A. This makes it attractive for applications such as a high energy junction in multi-junction photovoltaics, terahetrtz emission, and as a substrate for yellow, amber, orange, and red AlGaInP LEDs. However, bulk <span class="hlt">growth</span> of GaxIn1-xP ternary III-V semiconductor crystals using elemental Ga-In-P melts or pseudo-binary GaP-InP melts is significantly challenging due to the high vapor pressure of phosphorus at the typical <span class="hlt">growth</span> temperatures, the large variation in the lattice constant of the constituent binaries, and the slow <span class="hlt">growth</span> rates necessary in order to avoid the formation of cracks, dislocations, and multiphase inhomogeneities. Lowering the <span class="hlt">growth</span> temperature is desirable such that the vapor pressure of phosphorus can be more easily managed. Low <span class="hlt">growth</span> temperatures can be achieved by using gallium or indium rich solutions, as is currently used for liquid <span class="hlt">phase</span> epitaxy. However, this approach is less attractive for growing bulk crystals due to numerous experimental difficulties such as high segregation of gallium in indium as well as sticking of the <span class="hlt">growth</span> solution to the crucible wall and to the grown crystal, making crystal extraction without causing damage challenging. The objective of this research is to establish the conditions required for the <span class="hlt">growth</span> of uniform composition bulk crystals of GaxIn 1-xP at any desired composition from a stoichiometric GaxIn 1-xPySb1-y quaternary melt, as well as conditions for compositional grading from a binary III-V material seed. Due to large number of conditions of melt composition and temperature that are possible, trial</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1989JAP....65.3044H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1989JAP....65.3044H"><span>Gas-<span class="hlt">phase</span> kinetics during diamond <span class="hlt">growth</span>: CH4 as-<span class="hlt">growth</span> species</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Harris, Stephen J.</p> <p>1989-04-01</p> <p>We have used a one-dimensional kinetic analysis to model the gas-<span class="hlt">phase</span> chemistry that occurred during the diamond <span class="hlt">growth</span> experiments of Chauhan, Angus, and Gardner [J. Appl. Phys. 47, 4746 (1976)]. In those experiments the weight of diamond seed crystals heated by lamps in a CH4/H2 environment was monitored by a microbalance. No filament or electric discharge was present. Our analysis shows that diamond <span class="hlt">growth</span> occurred in this system by direct reaction of CH4 on the diamond surface. C2H2 and CH3, which have been proposed as diamond <span class="hlt">growth</span> species, played no significant role there, although our results do not address their possible contributions in other systems such as filament- or plasma-assisted diamond <span class="hlt">growth</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AIPC.1211..903O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AIPC.1211..903O"><span>Monitoring <span class="hlt">Growth</span> of Closed Fatigue Crack Using Subharmonic <span class="hlt">Phased</span> Array</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ohara, Y.; Endo, H.; Hashimoto, M.; Shintaku, Y.; Yamanaka, K.</p> <p>2010-02-01</p> <p>To ensure the safety and reliability of atomic power plants and airplanes, the technique of monitoring closed fatigue cracks is requisite. Here we monitored the distribution of the crack depths and closure behavior in the length direction after 48000 and 87000 fatigue cycles using subharmonic <span class="hlt">phased</span> array for crack evaluation (SPACE). The crack depths in the subharmonic images were larger than those in the fundamental images. Specifically, the difference was larger at near the side surface than at the center. The percentage of the closed part varied with the crack <span class="hlt">growth</span> in the specimen. In addition, we fabricated shoe for SPACE to facilitate mechanical scanning. Thus, it was demonstrated that SPACE is useful in monitoring closed fatigue crack <span class="hlt">growth</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009SPIE.7449E..0ND','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009SPIE.7449E..0ND"><span>Characterization of secondary <span class="hlt">phases</span> in modified vertical Bridgman <span class="hlt">growth</span> CZT</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Duff, Martine C.; Lynn, Kelvin G.; Jones, Kelly; Dai, Zurong R.; Bradley, John P.; Teslich, Nick</p> <p>2009-08-01</p> <p>CdZnTe or "CZT" crystals are highly suitable for use as a room temperature based spectrometer for the detection and characterization of gamma radiation. Over the last decade, the methods for growing high quality CZT have improved the quality of the produced crystals however there are material features that can influence the performance of these materials as radiation detectors. For example, various structural heterogeneities within the CZT crystals, such as twinning, pipes, grain boundaries (polycrystallinity), and secondary <span class="hlt">phases</span> (SP) can have a negative impact on the detector performance. In this study, a CZT material was grown by the modified vertical Bridgman <span class="hlt">growth</span> (MVB) method with zone leveled <span class="hlt">growth</span> without excess Te in the melt. Visual observations of material from the <span class="hlt">growth</span> of this material revealed significant voids and SP. Samples from this material were analyzed using various analytical techniques to evaluate its electrical properties, purity and detector performance as radiation spectrometers and to determine the morphology, dimension and elemental /structural composition of one of the SP in this material. This material was found to have a high resistivity but poor radiation spectrometer performance. It had SP that were rich in polycrystalline aluminum oxide (Al2O3), metallic Te and polycrystalline CdZnTe and 15 to 50 μm in diameter. Bulk elemental analyses of sister material from elsewhere in the boule did not contain high levels of Al so there is considerable elemental impurity heterogeneity within the boule from this <span class="hlt">growth</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/961881','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/961881"><span>Characterization of secondary <span class="hlt">phases</span> in modified vertical bridgman <span class="hlt">growth</span> czt</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Duff, Martine</p> <p>2009-07-10</p> <p>CdZnTe or 'CZT' crystals are highly suitable for use as a room temperature based spectrometer for the detection and characterization of gamma radiation. Over the last decade, the methods for growing high quality CZT have improved the quality of the produced crystals however there are material features that can influence the performance of these materials as radiation detectors. For example, various structural heterogeneities within the CZT crystals, such as twinning, pipes, grain boundaries (polycrystallinity), and secondary <span class="hlt">phases</span> (SP) can have a negative impact on the detector performance. In this study, a CZT material was grown by the modified vertical Bridgman <span class="hlt">growth</span> (MVB) method with zone leveled <span class="hlt">growth</span> without excess Te in the melt. Visual observations of material from the <span class="hlt">growth</span> of this material revealed significant voids and SP. Three samples from this material was analyzed using various analytical techniques to evaluate its electrical properties, purity and detector performance as radiation spectrometers and to determine the morphology, dimension and elemental/structural composition of one of the SP in this material. This material was found to have a high resistivity but poor radiation spectrometer performance. It had SP that were rich in polycrystalline aluminum oxide (Al{sub 2}O{sub 3}), metallic Te and polycrystalline CdZnTe and 15 to 50 {micro}m in diameter. Bulk elemental analyses of sister material from elsewhere in the boule did not contain high levels of Al so there is considerable elemental impurity heterogeneity within the boule from this <span class="hlt">growth</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6464246','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6464246"><span>Analysis of particle <span class="hlt">growth</span> by coalescence during liquid <span class="hlt">phase</span> sintering</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Takajo, S.; Kaysser, W.A.; Petzow, G.</p> <p>1984-06-01</p> <p>A statistical approach has been applied to particle coarsening during liquid <span class="hlt">phase</span> sintering assuming direct particle coalescence as basic <span class="hlt">growth</span> mechanism instead of Ostwald ripening. The coalescence process controlled by diffusion through the melt results in an increase of the average particle size proportional to the cube root of sintering time. After a short initial sintering interval the particle size distribution approaches a unique normalized form which is broader than forms predicted by Ostwald ripening theories. The effect of preferred coalescence possibilities for definite particle size ranges and the effect of concurrent coalescence and Ostwald ripening are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994PhRvL..72.1722A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994PhRvL..72.1722A"><span><span class="hlt">Growth</span> of manganese filled carbon nanofibers in the vapor <span class="hlt">phase</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ajayan, P. M.; Colliex, C.; Lambert, J. M.; Bernier, P.; Barbedette, L.; Tence, M.; Stephan, O.</p> <p>1994-03-01</p> <p>We report the vapor <span class="hlt">phase</span> <span class="hlt">growth</span> of partially filled graphitic fibers, 20-30 nm in diameter and up to a micron in length, during a manganese catalyzed carbon electric arc discharge. The fiber morphology resembles that of catalytic chemical vapor deposited carbon filaments but the inside hollow contains intermittent precipitates and continuous filling of Mn that at times occupy >50% of fiber lengths. Transmission electron microscopy and electron energy loss line spectra show that the fillings form as solid cores and may correspond to pure metal.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM51E2596H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM51E2596H"><span>Statistical comparison of inter-<span class="hlt">substorm</span> timings in global magnetohydrodynamics (MHD) and observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Haiducek, J. D.; Welling, D. T.; Morley, S.; Ozturk, D. S.</p> <p>2015-12-01</p> <p>Magnetospheric <span class="hlt">substorms</span> are events in which energy stored in the magnetotail is released into the auroral zone and into the downstream solar wind. Because of the complex, nonlinear, and possibly chaotic nature of the <span class="hlt">substorm</span> energy release mechanism, it may be extremely difficult to forecast individual <span class="hlt">substorms</span> in the near term. However, the inter-<span class="hlt">substorm</span> timing (the amount of time elapsed between <span class="hlt">substorms</span>) can be reproduced in a statistical sense, as was demonstrated by Freeman and Morley (2004) using their Minimal <span class="hlt">Substorm</span> Model (MSM), a simple solar-wind driven model with the only free parameter being a recurrence time. The goal of the present work is to reproduce the observed distribution of inter-<span class="hlt">substorm</span> timings with a global MHD model. The period of 1-31 January 2005 was simulated using the Space Weather Modeling Framework (SWMF), driven by solar wind observations. <span class="hlt">Substorms</span> were identified in the model output by synthesizing surface magnetometer data and by looking for tailward-moving plasmoids. <span class="hlt">Substorms</span> identified in the MHD model are then compared with observational data from the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) spacecraft, Los Alamos National Laboratory (LANL) geostationary satellite energetic particle data, and surface magnetometer data. For each dataset (MHD model and observations), we calculate the <span class="hlt">substorm</span> occurrence rate, and for the MHD model we additionally calculate the timing error of the <span class="hlt">substorm</span> onsets relative to the observed <span class="hlt">substorms</span>. Finally, we calculate distribution functions for the inter-<span class="hlt">substorm</span> timings in both the observations and the model. The results of this analysis will guide improvements to the MHD-based <span class="hlt">substorm</span> model, including the use of Hall MHD and embedded particle in cell (EPIC), leading to a better reproduction of the observed inter-<span class="hlt">substorm</span> timings and an improved understanding of the underlying physical processes. ReferencesM. P. Freeman and S. K. Morley. A minimal <span class="hlt">substorm</span> model that</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007JASTP..69..955G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007JASTP..69..955G"><span>Determination of a geomagnetic storm and <span class="hlt">substorm</span> effects on the ionospheric variability from GPS observations at high latitudes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gómez, Luis; Ignacio Sabbione, Juan; Andrea van Zele, María; Meza, Amalia; Brunini, Claudio</p> <p>2007-06-01</p> <p>The aim of this work is to characterize the ionospheric electron content variability during a standard and simple geomagnetic storm, and <span class="hlt">substorms</span> during it. The analysis is based on tying the geomagnetic disturbances including the signatures of the current wedge formed during the <span class="hlt">substorm</span> expansion <span class="hlt">phase</span>, with the variability of ionospheric vertical total electron content (VTEC) in local time; for this reason the VTEC is computed for complete geographical longitude coverage at subauroral and auroral latitudes. The study is based on the geomagnetic storm befallen on April 6 and 7, 2000 (near the equinox) and the TEC are computed from global positioning system (GPS). The main results can be divided into three groups: (a) when the geomagnetic storm starts between pre-midnight and dawn, a minimum of VTEC is recorded, lasting all the long day (ionospheric storm negative <span class="hlt">phase</span>); also the nighttime electron content may decrease below the corresponding for quiet days; but near the 60 of geomagnetic latitude the ionization polar tongue can be observed at noon, superimposed to the negative <span class="hlt">phase</span>; (b) computed by GPS stations placed lower than 50, when the geomagnetic storm starts between dawn and noon the VTEC recorded a positive <span class="hlt">phase</span>, but if it starts at noon a dusk effect is recorded; those located between 50 and 60 show a sudden increase and later sudden decrease to nocturnal values, (c) when the geomagnetic storm starts between afternoon and sunset, at stations located lower than 50 a dusk effect and an ionospheric negative <span class="hlt">phase</span> during the next day are recorded, but if the GPS stations are located at higher latitude than 50 the VTEC representation shows the nocturnal end of the ionization polar tongue. Expansion <span class="hlt">phases</span> of <span class="hlt">substorms</span> are shown as small VTEC variations recorded for a short time: decreases if the <span class="hlt">substorm</span> happens between dawn and midday; enhancements during the fall of the ionospheric positive <span class="hlt">phase</span>. From the comparison with the results obtained by other</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFMSM71A0578H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFMSM71A0578H"><span>Correlation of plasma and field behaviors in the near-Earth magnetotail with <span class="hlt">substorm</span> injections</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hori, T.; Ohtani, S.; Lui, A. T.; McEntire, R. W.; Maezawa, K.; Saito, Y.; Mukai, T.; Reeves, G. D.</p> <p>2002-12-01</p> <p>We have investigated statistically correlation of plasma flows, energization, and field variations observed by the Geotail spacecraft with particle injections observed at geosynchronous orbit. For this study, we visually inspected both Geotail and the Los Alamos National Laboratory (LANL) geosynchronous satellites data during Apr., 1995 - Mar., 2001 and have identified 50 conjunction events in which Geotail observed the near-Earth plasma sheet (-5 Re > X > -17 Re) when LANL observed dispersionless injection of energetic particles at geosynchronous distance on the nightside. We have made a superposed epoch analysis of plasma and field variations in the near-Earth plasma sheet by referring to the time of the associated dispersionless injections. The result is that, in all of the cases where Geotail and LANL are located closely in the dawn-dusk direction (|dY| < 3 Re), Geotail observed a gradual |Bx| increase prior to the injection time and then observed a sharp decrease in |Bx| as well as a rapid Bz increase around the injection time. These field signatures are consistent with the field stretching during the <span class="hlt">growth</span> <span class="hlt">phase</span> and subsequent dipolarization associated with a <span class="hlt">substorm</span> onset. In addition to the field signatures, flux enhancements of energetic (>30 keV) ions and electrons are also observed in most of the cases when Geotail reenters the plasma sheet as expected from the thickening of the plasma sheet after onset. On the other hand, in the cases in which Geotail and LANL are separated azimuthally from each other (|dY| > 3 Re), the |Bx| increase prior to the injection time is not seen clearly and the Bz increase tends to be less sharp and smaller than those in the former cases. This result suggests that the thinning and subsequent thickening of the plasma sheet occurs more markedly at the injection sector and such a change in the field configuration becomes weaker away from there. We have also examined the spatial evolution in the X-Y plane of the region of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFMSM52B..01V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFMSM52B..01V"><span>Signatures of Pseudo-breakup, Breakup of a Full <span class="hlt">Substorm</span> Onset, and Poleward Border Intensifications Compared.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Voronkov, I.; Donovan, E. F.; Samson, J. C.</p> <p>2001-12-01</p> <p>For several exceptional events, we use ground-based and in-situ data to compare the ionospheric, geostationary, and mid-tail signatures of the pseudo-breakup, breakup, and poleward border intensifications (PBIs). In doing so, we utilize CANOPUS magnetometer and multi-wavelength photometer and All-sky imager data, as well as field measurements provided by the GOES 8, GOES 9, and Geotail spacecraft. We have identified a set of distinguishable signatures of each process. Pseudo-breakup consists of two distinct stages: near-linear arc intensification corresponding to the ``explosive <span class="hlt">growth</span> <span class="hlt">phase</span>" at geostationary orbit, and poleward vortex expansion that starts simultaneously with explosive onset of short period pulsations (Pi1, Pi2) and dipolarization observed at geostationary orbit. It can be accompanied by local perturbations of the equatorward part of the electron precipitation region and by formation of the <span class="hlt">substorm</span>-like local current system but neither by optical signatures of the lobe flux reconnection nor by perturbations in the mid-tail. It typically saturates near the equatorward border of the electron precipitation region producing a mushroom-like auroral structure. Breakup starts with the same two-stage initial scenario of the arc intensification and vortex evolution but it rapidly expands poleward and is accompanied by optical signatures of reconnection onset, namely the aurora develops into a cell-like structure of the size compatible with the whole auroral zone width. This occurs at the time when mid-tail disruption signatures are observed. Full onset launches a second, more global, larger Pi2 burst. Finally, we show an example of PBIs observed as long period pulses of electron precipitation at the poleward border of auroral region, followed by the high-latitude proton aurora. The commencement of PBI coincided with bursty bulk flows and pulses of plasma energization in the mid-tail. Observed features are discussed with respect to recent ideas claiming</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('https://ntrs.nasa.gov/search.jsp?R=19820058217&hterms=Fukushima&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DFukushima','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820058217&hterms=Fukushima&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DFukushima"><span>Theoretical magnetograms based on quantitative simulation of a magnetospheric <span class="hlt">substorm</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.-K.; Wolf, R. A.; Karty, J. L.; Harel, M.</p> <p>1982-01-01</p> <p><span class="hlt">Substorm</span> currents derived from the Rice University computer simulation of the September 19, 1976 <span class="hlt">substorm</span> event are used to compute theoretical magnetograms as a function of universal time for various stations, integrating the Biot-Savart law over a maze of about 2700 wires and bands that carry the ring, Birkeland and horizontal ionospheric currents. A comparison of theoretical results with corresponding observations leads to a claim of general agreement, especially for stations at high and middle magnetic latitudes. Model results suggest that the ground magnetic field perturbations arise from complicated combinations of different kinds of currents, and that magnetic field disturbances due to different but related currents cancel each other out despite the inapplicability of Fukushima's (1973) theorem. It is also found that the dawn-dusk asymmetry in the horizontal magnetic field disturbance component at low latitudes is due to a net downward Birkeland current at noon, a net upward current at midnight, and, generally, antisunward-flowing electrojets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820058217&hterms=fukushima&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dfukushima','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820058217&hterms=fukushima&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dfukushima"><span>Theoretical magnetograms based on quantitative simulation of a magnetospheric <span class="hlt">substorm</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.-K.; Wolf, R. A.; Karty, J. L.; Harel, M.</p> <p>1982-01-01</p> <p><span class="hlt">Substorm</span> currents derived from the Rice University computer simulation of the September 19, 1976 <span class="hlt">substorm</span> event are used to compute theoretical magnetograms as a function of universal time for various stations, integrating the Biot-Savart law over a maze of about 2700 wires and bands that carry the ring, Birkeland and horizontal ionospheric currents. A comparison of theoretical results with corresponding observations leads to a claim of general agreement, especially for stations at high and middle magnetic latitudes. Model results suggest that the ground magnetic field perturbations arise from complicated combinations of different kinds of currents, and that magnetic field disturbances due to different but related currents cancel each other out despite the inapplicability of Fukushima's (1973) theorem. It is also found that the dawn-dusk asymmetry in the horizontal magnetic field disturbance component at low latitudes is due to a net downward Birkeland current at noon, a net upward current at midnight, and, generally, antisunward-flowing electrojets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19880059342&hterms=injection+wells&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dinjection%2Bwells','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19880059342&hterms=injection+wells&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dinjection%2Bwells"><span>Dynamic <span class="hlt">substorm</span> injections - Similar magnetospheric phenomena at earth and Mercury</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Christon, S. P.; Feynman, J.; Slavin, J. A.</p> <p>1987-01-01</p> <p>Correlations between energetic electrons, plasma electrons, and magnetic fields during the Mercury 1 energetic particle events are examined and comparisons are made with several well-documented <span class="hlt">substorm</span> injections at the earth. The data reveal that the B and B-prime events possess the same characteristics as single-point observations of terrestrial dynamic injections. Several recently discovered correlations between the energetic electrons, plasma electrons, and magnetic fields at Mercury are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA087700','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA087700"><span>Quantitative Simulation of a Magnetospheric <span class="hlt">Substorm</span>. 2. Comparison with Observations,</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1980-01-23</p> <p>we overestimated the polar-boundary potential drop; consequently the p) asma -sheet ions were injected deeper into the magnetosphere than was the case...Magnetospheric <span class="hlt">Substorms</span> and Related Plasma Processes, Los Alamos, New Mexico , October 1978 and to be published in Astrophysics and Space Science Library...and Related Plasma Processes, Los Alamos, New Mexico , October 1978, published in Astrophysics and Space Science Library Series,p.14 3, Yasuhara, F., and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA090017','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA090017"><span>Phenomenological and Theoretical Studies on Magnetic Indicators of <span class="hlt">Substorm</span> Activity.</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1980-03-21</p> <p>docummeni-we report results of studies made on <span class="hlt">substorm</span> de- tection, behavior, and irelationship to magnetospheric processes . A scheme is developed whereby...regard. Field aligned currents drive ionospheric current systems on a global scale. A model is developed to describe this process for quiet and disturbed...currents and ionospheric closure currents., This process is discussed and estimates are developed for the relative ’c6ntributions of Pederson and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM53E..06G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM53E..06G"><span>Spectacular ionospheric flow structures associated with <span class="hlt">substorm</span> auroral onset</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gallardo-Lacourt, B. I.; Nishimura, Y.; Lyons, L. R.; Zou, Y.; Angelopoulos, V.; Donovan, E.; Mende, S. B.; Ruohoniemi, J.; McWilliams, K. A.; Nishitani, N.</p> <p>2013-12-01</p> <p>Auroral observations have shown that brightening at <span class="hlt">substorm</span> auroral onset consists of azimuthally propagating beads forming along a pre-existing arc. However, the ionospheric flow structure related to this wavy auroral structure has not been previously identified. We present 2-d line-of-sight flow observations and auroral images from the SuperDARN radars and the THEMIS ground-based all-sky-imager array to investigate the ionospheric flow pattern associated with the onset. We have selected events where SuperDARN was operating in the THEMIS mode, which provides measurements along the northward looking radar beam that have time resolution (6 s) comparable to the high time resolution of the imagers and gives us a unique tool to detect properties of flows associated with the <span class="hlt">substorm</span> onset instability. We find very fast flows (~1000 m/s) that initiated simultaneously with the onset arc beads propagating across the THEMIS-mode beam meridian. The flows show oscillations at ~9 mHz, which corresponds to the periodicity of the auroral beads propagating across the radar beam. 2-d radar measurements also show a wavy pattern in the azimuthal direction with a wavelength of ~74 km, which is close to the azimuthal separation of individual beads, although this determination is limited by the 2 minute radar scan period. These strong correlations (in time and space) between auroral beading and the fast ionospheric flows suggest that these spectacular flows are an important feature of the <span class="hlt">substorm</span> onset instability within the inner plasma sheet. Also, a clockwise flow shear was observed in association with individual auroral beads, suggesting that such flow shear is a feature of the unstable <span class="hlt">substorm</span> onset waves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.7481G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.7481G"><span>The Large-Scale Current System During Auroral <span class="hlt">Substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gjerloev, Jesper</p> <p>2015-04-01</p> <p>The <span class="hlt">substorm</span> process has been discussed for more than four decades and new empirical large-scale models continue to be published. The continued activity implies both the importance and the complexity of the problem. We recently published a new model of the large-scale <span class="hlt">substorm</span> current system (Gjerloev and Hoffman, JGR, 2014). Based on data from >100 ground magnetometers (obtained from SuperMAG), 116 isolated <span class="hlt">substorms</span>, global auroral images (obtained by the Polar VIS Earth Camera) and a careful normalization technique we derived an empirical model of the ionospheric equivalent current system. Our model yield some unexpected features that appear inconsistent with the classical single current wedge current system. One of these features is a distinct latitudinal shift of the westward electrojet (WEJ) current between the pre- and post-midnight region and we find evidence that these two WEJ regions are quasi disconnected. This, and other observational facts, led us to propose a modified 3D current system configuration that consists of 2 wedge type systems: a current wedge in the pre-midnight region (bulge current wedge), and another current wedge system in the post-midnight region (oval current wedge). The two wedge systems are shifted in latitude but overlap in local time in the midnight region. Our model is at considerable variance with previous global models and conceptual schematics of the large-scale <span class="hlt">substorm</span> current system. We speculate that the data coverage, the methodologies and the techniques used in these previous global studies are the cause of the differences in solutions. In this presentation we present our model, compare with other published models and discuss possible causes for the differences.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSM51C4259W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSM51C4259W"><span>The Differences in Onset Time of Conjugate <span class="hlt">Substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Weygand, J. M.; Zesta, E.; McPherron, R. L.; Hsu, T. S.</p> <p>2014-12-01</p> <p>The auroral electrojet (AE) index is traditionally calculated from 13 ground magnetometer stations located around the typical northern auroral oval location. Similar coverage in the Southern Hemisphere index (SAE) does not exist, so the AE calculation has only been performed using Northern Hemisphere data. In the present study, we use seven southern auroral region ground magnetometers as well as their conjugate Northern Hemisphere data to calculate conjugate AE indices for 274 days covering all four seasons. With this dataset over 1200 <span class="hlt">substorm</span> onsets have been identified in the SAE index using the technique of Hsu et al. [2012]. A comparison of the SAE index with the world data center standard AE index shows that the <span class="hlt">substorm</span> onsets do not always occur at the same time with differences on the order of several minutes. In this study we examine the differences in the onset time and the reason for those differences using our conjugate AE indices and using pairs of conjugate ground magnetometer stations. Specifically, we used the pair of stations at West Antarctica Ice Sheet Divide and Sanikiluaq, Canada and Syowa, Antarctica and Tjörnes, Iceland. The largest differences in onset time appear to be related to the IMF Bz and magnetic field line length. Differences on the order of minutes for the onset time of conjugate <span class="hlt">substorms</span> have serious implications for <span class="hlt">substorm</span> theories. The problem is that waves from a current disruption region to the mid tail, or flows from the mid tail to the current disruption region take the same amount of time (~2 minutes), which makes it difficult to decide where the onset disturbance is initiated, particularly when onset indicators have differences on the order of minutes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM11B2091C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM11B2091C"><span>Flow Pattern relative to the <span class="hlt">Substorm</span> Current Wedge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chu, X.; McPherron, R. L.; Hsu, T.</p> <p>2013-12-01</p> <p>Magnetospheric <span class="hlt">substorms</span> play a key role in the coupling of the solar wind and the magnetosphere. The <span class="hlt">Substorm</span> Current Wedge (SCW) is a key element in the present physical model of <span class="hlt">substorms</span>. It is widely accepted that the SCW is created by earthward busty flows, but the generation mechanism is still unknown. Previous studies suggest pressure gradients and magnetic vortices are possible candidates. Due to the sparse coverage of satellites in space, these studies were strongly dependent on the assumption that the satellites were in the generation region of the field-aligned currents (FAC) forming the SCW. In this work, we take advantage of an inversion technique that determines the parameters describing the SCW and perform a statistical study on the plasma and magnetic field parameters of the flow pattern relative to the SCW. The inversion technique finds the location and the intensity of the SCW from midlatitude magnetic data. The technique has been validated using auroral observations, Equivalent Ionospheric Currents (EIC), SYM-H index from SuperMAG, and magnetic perturbations at geosynchronous orbit by the GOES satellite. A database of <span class="hlt">substorm</span> events has been created using midlatitude positive bays, which are the ground signature of the SCW at lower latitudes. The inversion technique is applied to each event in the database to determine the location of the origin of the SCW. The inversion results are also used to find conjunction events with space observations from VAP (RBSP), THEMIS and GOES. The plasma and magnetic field parameters such as the pressure gradient and magnetic vorticity are then categorized as a function of their location relative to the origin of the SCW. How the distribution/pattern of the pressure gradient and vorticity are related to the properties of the SCW (locations and intensity of the FAC), and flows (entropy, velocity and density) will be determined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/146015','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/146015"><span>On the dynamical development of the downward field-aligned current in the <span class="hlt">substorm</span> current wedge</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pellinen, R.J.; Pulkkinen, T.I.; Huuskonen, A.</p> <p>1995-08-01</p> <p>We report observations of a <span class="hlt">substorm</span> event on March 4, 1979, onset at 2236 UT, which confirm the participation of the upward accelerated ionospheric electrons in the <span class="hlt">substorm</span> current wedge current during the first few minutes after the <span class="hlt">substorm</span> onset. The slow ions do not contribute much to the downward current immediately after the <span class="hlt">substorm</span> onset, whereas the precipitating magnetospheric electrons quickly set up the upward current. A scanning photometer was centrally placed at the center of the downward current during the event. The observations suggest that the current was mainly caused by cold ionospheric electrons. 27 refs., 8 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19720029853&hterms=vertical+electric+sounding&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dvertical%2Belectric%2Bsounding','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19720029853&hterms=vertical+electric+sounding&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dvertical%2Belectric%2Bsounding"><span>Vertical motions of the midlatitude F2 layer during magnetospheric <span class="hlt">substorms</span>.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Park, C. G.; Meng, C.</p> <p>1971-01-01</p> <p>Use of ground-based ionosonde records from midlatitude stations during winter nights to study vertical motions of the F2 layer associated with magnetospheric <span class="hlt">substorms</span>. The results show that during <span class="hlt">substorms</span> the F2 layer is lifted upward in the premidnight sector and pushed downward in the postmidnight sector. These motions are interpreted in terms of E x B drifts, the electric field being eastward on the eveningside and westward on the morningside. The results emphasize the importance of <span class="hlt">substorm</span> effects on the midlatitude F region and the potential of ground-based hf sounding techniques in studying magnetospheric <span class="hlt">substorms</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatSR...625191C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatSR...625191C"><span>The lag-<span class="hlt">phase</span> during diauxic <span class="hlt">growth</span> is a trade-off between fast adaptation and high <span class="hlt">growth</span> rate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chu, Dominique; Barnes, David J.</p> <p>2016-04-01</p> <p>Bi-phasic or diauxic <span class="hlt">growth</span> is often observed when microbes are grown in a chemically defined medium containing two sugars (for example glucose and lactose). Typically, the two <span class="hlt">growth</span> stages are separated by an often lengthy <span class="hlt">phase</span> of arrested <span class="hlt">growth</span>, the so-called lag-<span class="hlt">phase</span>. Diauxic <span class="hlt">growth</span> is usually interpreted as an adaptation to maximise population <span class="hlt">growth</span> in multi-nutrient environments. However, the lag-<span class="hlt">phase</span> implies a substantial loss of <span class="hlt">growth</span> during the switch-over. It therefore remains unexplained why the lag-<span class="hlt">phase</span> is adaptive. Here we show by means of a stochastic simulation model based on the bacterial PTS system that it is not possible to shorten the lag-<span class="hlt">phase</span> without incurring a permanent <span class="hlt">growth</span>-penalty. Mechanistically, this is due to the inherent and well established limitations of biological sensors to operate efficiently at a given resource cost. Hence, there is a trade-off between lost <span class="hlt">growth</span> during the diauxic switch and the long-term <span class="hlt">growth</span> potential of the cell. Using simulated evolution we predict that the lag-<span class="hlt">phase</span> will evolve depending on the distribution of conditions experienced during adaptation. In environments where switching is less frequently required, the lag-<span class="hlt">phase</span> will evolve to be longer whereas, in frequently changing environments, the lag-<span class="hlt">phase</span> will evolve to be shorter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM43B2306M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM43B2306M"><span>Interaction of <span class="hlt">Substorm</span> Injections with the Subauroral Geospace</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mishin, E. V.</p> <p>2013-12-01</p> <p>The subauroral geospace includes the ring current (RC), innermost part of the outer radiation belt, and plasmasphere adjacent to the electron plasma sheet boundary and conjugate ionosphere. The purpose of this paper is to extend understanding of the active subauroral geospace by exploring subauroral events in the near-equatorial magnetosphere and conjugate ionosphere soon after the onsets of individual <span class="hlt">substorms</span>. Their fast appearance is consistent with the propagation of <span class="hlt">substorm</span> injections. The documented features in the premidnight sector are described in terms of the effect of a short circuit of <span class="hlt">substorm</span>-injected plasma jets over the plasmapause. The short-circuiting occurs when the cold plasma density exceeds a critical value of 5-10 c.c. As the polarization field at the front of the hot plasma jet is shorten out, the hot electrons are arrested, while the hot ions yet move inward. This provides a natural explanation of the long-known dispersionless auroral electron precipitation boundary and the SAID location just interior to the plasmapause. Enhanced plasma turbulence provides anomalous circuit resistivity and magnetic diffusion leading to a turbulent boundary layer adjacent to the plasmapause. The hot ions' inward motion stops when their pressure gradient is balanced by the polarization electric field. Then, the ions experiencing gradient-curvature drift move westward and their interaction with the plasmasphere creates strong wave structures on the duskside.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1918779G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1918779G"><span>Solar wind control of the local time of <span class="hlt">substorm</span> onset</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grocott, Adrian; Case, Nathan; Laundal, Karl; Laurens, Hannah; Milan, Steve</p> <p>2017-04-01</p> <p>We use solar wind and interplanetary magnetic field data, along with satellite global auroral imagery, to investigate what controls the magnetic local time (MLT) of <span class="hlt">substorm</span> onset. We find that <span class="hlt">substorm</span> onsets occur over a wide range of MLTs (18 - 4 hrs), with a typical MLT (mode) of 23 hrs. In agreement with previous studies, IMF BY , acts to move the onset to an earlier/later local time in the northern hemisphere and a later/earlier local time in the southern hemisphere, depending on the sign of BY , consistent with a twist of the conjugate magnetic field line. This effect explains a small fraction of the observed MLT variation (˜ 1 hr), but cannot account for the tendency of onset to be often displaced to earlier (< 23 hrs) or later (> 23 hrs) MLTs in both hemispheres. We also inspect the relationship between solar wind V Y and onset MLT, which also has a small, but measurable effect on the local time of <span class="hlt">substorm</span> onset. This effect acts in the same sense in the northern and southern hemispheres, moving onset to earlier times for positive V Y and later times for negative V Y . We find that a function relating both BY and V Y to onset MLT produces a better fit than a function based on either parameter alone.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://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="https://ntrs.nasa.gov/search.jsp?R=19760008620&hterms=Auroras&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DAuroras"><span>ATS-5 observations of plasma sheet particles before the expansion-<span class="hlt">phase</span> onset, appendix C.. [plasma-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 plasma sheet around its earthward edge during <span class="hlt">substorms</span> was studied by using high resolution (every 2.6 sec) measurements of proton and electron fluxes by ATS-5. In the injection region near midnight the flux increase at the expansion-<span class="hlt">phase</span> 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 plasma sheet is suggested as a cause of the above difference in flux variations during the <span class="hlt">growth</span> <span class="hlt">phase</span> of <span class="hlt">substorms</span>. Magnetograms and tables (data) are shown.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSM41B2436B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSM41B2436B"><span>Magnetospheric Multiscale (MMS) and Van Allen Probes Study of <span class="hlt">Substorm</span> Injections</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baker, D. N.; Jaynes, A. N.; Leonard, T. W.; Cohen, I.; Mauk, B.; Fennell, J. F.</p> <p>2016-12-01</p> <p>We study episodes of significantly southward interplanetary magnetic field (IMF) that occurred with periods of high solar wind speed (Vsw500 km/s). We focus on events during the orbital <span class="hlt">phases</span> with MMS spacecraft apogees in the Earth's local midnight region. Key events during MMS magnetotail passages in 2015 and 2016 show that the magnetosphere progresses through a clear sequence of energy-loading and stress-developing states until the entire system suddenly reconfigures. Energetic electrons, plasma, and magnetic fields measured by the four MMS spacecraft reveal sharp dipolarization front characteristics. It is seen that magnetospheric <span class="hlt">substorm</span> activity provides a "seed" electron population as observed by MMS particle sensors. Isolated particle injections at higher altitudes are closely related to enhancements in electron flux deeper within the inner magnetosphere. Particle injection events observed by the four MMS spacecraft subsequently feed the enhancement of the outer radiation belt observed by Van Allen Probes mission sensors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19760016013&hterms=Tellurium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DTellurium','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19760016013&hterms=Tellurium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DTellurium"><span>Crystal <span class="hlt">growth</span> from the vapor <span class="hlt">phase</span> experiment MA-085</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wiedemeir, H.; Sadeek, H.; Klaessig, F. C.; Norek, M.</p> <p>1976-01-01</p> <p>Three vapor transport experiments on multicomponent systems were performed during the Apollo Soyuz mission to determine the effects of microgravity forces on crystal morphology and mass transport rates. The mixed systems used germanium selenide, tellurium, germanium tetraiodide (transport agent), germanium monosulfide, germanium tetrachloride (transport agent), and argon (inert atmosphere). The materials were enclosed in evacuated sealed ampoules of fused silica and were transported in a temperature gradient of the multipurpose electric furnace onboard the Apollo Soyuz spacecraft. Preliminary evaluation of 2 systems shows improved quality of space grown crystals in terms of <span class="hlt">growth</span> morphology and bulk perfection. This conclusion is based on a direct comparison of space grown and ground based crystals by means of X-ray diffraction, microscopic, and chemical etching techniques. The observation of greater mass transport rates than predicted for a microgravity environment by existing vapor transport models indicates the existence of nongravity caused transport effects in a reactive solid/gas <span class="hlt">phase</span> system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19730041404&hterms=ohms+law&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dohms%2Blaw','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19730041404&hterms=ohms+law&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dohms%2Blaw"><span>Inertial magnetic field reconnection and magnetospheric <span class="hlt">substorms</span>.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Van Hoven, G.; Cross, M. A.</p> <p>1973-01-01</p> <p>We describe and calculate the <span class="hlt">growth</span> rate of a magnetohydrodynamic neutral-sheet instability due to electron-inertia terms in the infinite-conductivity Ohm's law. The results are compared with an approximate Vlasov-equation calculation, and are shown to be particularly germane to the geomagnetic-tail instability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22318037','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22318037"><span>ZnO nanorod <span class="hlt">growth</span> by plasma-enhanced vapor <span class="hlt">phase</span> transport with different <span class="hlt">growth</span> durations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kim, Chang-Yong; Oh, Hee-bong; Ryu, Hyukhyun; Yun, Jondo; Lee, Won-Jae</p> <p>2014-09-01</p> <p>In this study, the structural properties of ZnO nanostructures grown by plasma-enhanced vapor <span class="hlt">phase</span> transport (PEVPT) were investigated. Plasma-treated oxygen gas was used as the oxygen source for the ZnO <span class="hlt">growth</span>. The structural properties of ZnO nanostructures grown for different durations were measured by scanning electron microscopy, x-ray diffraction, and transmission electron microscopy. The authors comprehensively analyzed the <span class="hlt">growth</span> of the ZnO nanostructures with different <span class="hlt">growth</span> durations both with and without the use of plasma-treated oxygen gas. It was found that PEVPT has a significant influence on the <span class="hlt">growth</span> of the ZnO nanorods. PEVPT with plasma-treated oxygen gas facilitated the generation of nucleation sites, and the resulting ZnO nanorod structures were more vertical than those prepared by conventional VPT without plasma-treated oxygen gas. As a result, the ZnO nanostructures grown using PEVPT showed improved structural properties compared to those prepared by the conventional VPT method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/972074','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/972074"><span>Indium <span class="hlt">Growth</span> and Island Height Control on Si Submonolayer <span class="hlt">Phases</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chen, Jizhou</p> <p>2009-01-01</p> <p>) have a wave length of 13.4 nm so it can curve on the surface of an sample to make structure as small as the order of 10 nm. however, lithograph usually causes permanent damages to the surface and in many cases the QDs are damaged during the lithograph and therefore result in high percentage of defects. Quantum size effect has attracted more and more interests in surface science due to many of its effects. One of its effects is the height preference in film growing and the resulting possibility of uniformly sized self-assemble nanostructure. The experiment of Pb islands on In 4x1 <span class="hlt">phase</span> shows that both the height and the width can be controlled by proper <span class="hlt">growth</span> conditions, which expands the <span class="hlt">growth</span> dimensions from 1 to 2. This discover leads us to study the In/Pb interface. In Ch.3, we found that the Pb islands growing on In 4x1-Si(111) surface which have uniform height due to QSE and uniform width due to the constriction of In 4x1 lattice have unexpected stability. These islands are stable in even RT, unlike usual nanostructures on Pb/Si surface which are stable only at low temperature. Since similar structures are usually grown at low temperature, this discovery makes the grown structures closer to technological applications. It also shows the unusual of In/Pb interface. Then we studied the In islands grown on Pb-α-√3x√3-Si(111) <span class="hlt">phase</span> in Ch.4. These islands have fcc structure in the first few layers, and then convert to bct structure. The In fcc islands have sharp height preference due to QSE like Pb islands. However, the preferred height is different (7 layer for Pb on Si 7x7 and 4 layer for Pb on In 4x1), due to the difference of interface. The In islands structure prefers to be bct than fcc with coverage increase. It is quantitatively supported by first-principle calculation. Unexpectedly, the In islands grown on various of In interfaces didn't show QSE effects and <span class="hlt">phase</span> transition from fcc and bct structures as on the Pb-α interface (Ch.6). In g(s) curve there</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005PhRvB..72n4509A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005PhRvB..72n4509A"><span><span class="hlt">Phase</span> conversion and interface <span class="hlt">growth</span> in <span class="hlt">phase</span>-separated 3He - 4He liquid mixtures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Abe, Haruka; Satoh, Takeo; Burmistrov, Serguei N.</p> <p>2005-10-01</p> <p>We have developed a method for measuring the transmission coefficient of a sound propagating through the interface in <span class="hlt">phase</span>-separated He3-He4 liquid mixtures. The method and the results are described with discussions by examining the <span class="hlt">phase</span>-conversion process of He3 quasiparticles driven to flow across the interface. From the data, we have determined the kinetic <span class="hlt">growth</span> coefficient of the interface, ξ(T,P,ω) , as a function of temperature, pressure, and frequency. The temperature range of the present investigation is about 2-100mK at the pressure mainly around 1bar with sound frequency 9.64, 14.4, and 32.4MHz . The main specific features observed for the kinetic <span class="hlt">growth</span> coefficient are, as follows: (i) there is a maximum at some temperature Tm(ω) depending on the frequency, (ii) above Tm(ω) , ξ decreases with the increase of temperature as ∝ω5/2T-3 , and (iii) below Tm(ω) , ξ becomes frequency independent and diminishes as a cube of temperature, T3 .</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999JGR...10410235P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999JGR...10410235P"><span>Ballooning instability in the presence of a plasma flow: A synthesis of tail reconnection and current disruption models for the initiation of <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pu, Z. Y.; Kang, K. B.; Korth, A.; Fu, S. Y.; Zong, Q. G.; Chen, Z. X.; Hong, M. H.; Liu, Z. X.; Mouikis, C. G.; Friedel, R. W. H.; Pulkkinen, T.</p> <p>1999-05-01</p> <p>The drift ballooning mode (DBM) instability near the inner edge of the plasma sheet (IEPS) is studied further by including a nonstationary earthward flow and flow shear in the analysis. Both equatorial and off-equatorial regions are considered. It is found that the presence of a decelerated earthward flow destabilizes both the M- and M+ branches of the DBM in a large portion of the current sheet near the IEPS and substantially increases the <span class="hlt">growth</span> rate of the instability. The flow shear in the premidnight sector causes the conventional ballooning mode to weakly subside, while it slightly enhances the <span class="hlt">growth</span> rate for the Alfvénic ballooning mode. The combination of the earthward flow and flow shear makes both the Alfvénic ballooning mode and conventional ballooning mode grow much faster than they would without the flow, giving rise to coupled Alfvénic slow magnetosonic waves, field-aligned currents, and the formation of a current wedge. A synthesis of tail reconnection and cross-tail current disruption scenarios is proposed for the <span class="hlt">substorm</span> global initiation process: When the fast flow produced by magnetic reconnection in the midtail abruptly decelerates at the IEPS, it compresses the plasma populations earthward of the front, transports momentum to them, and pushes them farther earthward. This creates the configuration instability in a large portion of the inner tail magnetic field lines on both the tailward side and earthward side of the braking point. As soon as the ionospheric conductance increases over a threshold level, the auroral electrojet is greatly intensified, which leads to the formation of the <span class="hlt">substorm</span> current wedge and dipolarization of the magnetic field. This <span class="hlt">substorm</span> paradigm combines the near-Earth neutral line and near-Earth current disruption scenarios for the initiation of <span class="hlt">substorms</span> and may also synthesize dynamical processes in the magnetosphere-ionosphere coupling and field line resonance during the <span class="hlt">substorm</span> onset. We intend to use this</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19667046','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19667046"><span>Microarray and functional analysis of <span class="hlt">growth</span> <span class="hlt">phase</span>-dependent gene regulation in Bordetella bronchiseptica.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nicholson, Tracy L; Buboltz, Anne M; Harvill, Eric T; Brockmeier, Susan L</p> <p>2009-10-01</p> <p><span class="hlt">Growth</span> <span class="hlt">phase</span>-dependent gene regulation has recently been demonstrated to occur in Bordetella pertussis, with many transcripts, including known virulence factors, significantly decreasing during the transition from logarithmic to stationary-<span class="hlt">phase</span> <span class="hlt">growth</span>. Given that B. pertussis is thought to have derived from a Bordetella bronchiseptica-like ancestor, we hypothesized that <span class="hlt">growth</span> <span class="hlt">phase</span>-dependent gene regulation would also occur in B. bronchiseptica. Microarray analysis revealed and quantitative real-time PCR (qRT-PCR) confirmed that <span class="hlt">growth</span> <span class="hlt">phase</span>-dependent gene regulation occurs in B. bronchiseptica, resulting in prominent temporal shifts in global gene expression. Two virulence phenotypes associated with these gene expression changes were tested. We found that <span class="hlt">growth</span>-dependent increases in expression of some type III secretion system (TTSS) genes led to a <span class="hlt">growth</span> <span class="hlt">phase</span>-dependent increase in a TTSS-dependent function, cytotoxicity. Although the transcription of genes encoding adhesins previously shown to mediate adherence was decreased in late-log and stationary <span class="hlt">phases</span>, we found that the adherence of B. bronchiseptica did not decrease in these later <span class="hlt">phases</span> of <span class="hlt">growth</span>. Microarray analysis revealed and qRT-PCR confirmed that <span class="hlt">growth</span> <span class="hlt">phase</span>-dependent gene regulation occurred in both Bvg(+) and Bvg(-) <span class="hlt">phase</span>-locked mutants, indicating that <span class="hlt">growth</span> <span class="hlt">phase</span>-dependent gene regulation in B. bronchiseptica can function independently from the BvgAS regulatory system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740012862','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740012862"><span>Electric and magnetic field observations during a <span class="hlt">substorm</span> of 24 February 1970</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.; Akasofu, S. I.</p> <p>1974-01-01</p> <p>A series of electric field measurements is reported which was obtained from the Injun 5 satellite along with a simultaneous magnetic disturbance observed in the interplanetary medium and on the ground during a magnetic <span class="hlt">substorm</span>. The <span class="hlt">substorm</span> analyzed took place on February 24, 1970. Prior to the onset of the <span class="hlt">substorm</span> a greatly enhanced anti-sunward plasma flow was observed over the polar cap. The enhanced plasma flow occurred about 30 minutes after a switch in the direction of the interplanetary magnetic field from northward to southward. The electric fields across the polar cap immediately before and during the <span class="hlt">substorm</span> were essentially unchanged indicating that an enhancement in the ionospheric conductivity rather than the electric field must be responsible for the large increase in the auroral electrojet current during the <span class="hlt">substorm</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6426849','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6426849"><span>The Earth's magnetosphere under continued forcing: <span class="hlt">Substorm</span> activity during the passage of an interplanetary magnetic cloud</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Farrugia, C.J.; Burlaga, L.F.; Lepping, R.P. ); Freeman, M.P. ); Takahashi, K. )</p> <p>1993-05-01</p> <p>This is the third of three papers dealing with the interaction of an interplanetary magnetic field with the earth's magnetosphere in Jan 1988. Here the authors report on <span class="hlt">substorm</span> observations made during this time period. They sampled information from six spacecraft and a larger number of ground based systems to serve as signals for the initiation of <span class="hlt">substorm</span> behavior. They relate the interplanetary magnetic field and plasma conditions to the time of observation of <span class="hlt">substorm</span> initiation. Current models tie <span class="hlt">substorm</span> occurrence to magnetic reconnection in the magnetosphere. The IMF B[sub y] and B[sub z] components varied slowly over a range of 20 nT on both sides of zero during this observation period. During the period of northward IMF the magnetosphere was quiescent, but during the period of southward IMF a large magnetic storm was initiated. During this interval <span class="hlt">substorms</span> were observed roughly every 50 minutes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920029440&hterms=f7&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Df7','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920029440&hterms=f7&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Df7"><span>DMSP F7 observations of a <span class="hlt">substorm</span> field-aligned current</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lopez, R. E.; Spence, H. E.; Meng, C.-I.</p> <p>1991-01-01</p> <p>Observations are described of a <span class="hlt">substorm</span> field-aligned current (FAC) system traversed by the DMSP F7 spacecraft just after 0300 UT on April 25, 1985. It is shown that the <span class="hlt">substorm</span> FAC portion of the current system was located equatorward of the boundary between open and closed field lines. The equatorward boundary of the <span class="hlt">substorm</span> FAC into the magnetotail was mapped using the Tsyganenko (1987) model, showing that the boundary corresponds to 6.9 earth radii. The result is consistent with the suggestion of Akasofu (1972) and Lopez and Lui (1990) that the region of <span class="hlt">substorm</span> initiation lies relatively close to the earth and the concept that an essential feature of <span class="hlt">substorms</span> is the disruption and diversion of the near-earth current sheet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..122.3087B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..122.3087B"><span>Quasiperiodic field-aligned current dynamics associated with auroral undulations during a <span class="hlt">substorm</span> recovery</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bunescu, C.; Marghitu, O.; Vogt, J.; Constantinescu, D.; Partamies, N.</p> <p>2017-03-01</p> <p>A <span class="hlt">substorm</span> recovery event in the early morning sector is explored by means of ground and spacecraft data. The ground data are provided by stations of the MIRACLE network, in northern Scandinavia and Svalbard, while spacecraft data are observed by the Cluster satellites, toward the end of the recovery <span class="hlt">phase</span>. Additional information is provided by the Fast Auroral SnapshoT (FAST) satellite, conjugate to Cluster 3 (C3). A prominent signature in the Cluster data is the low-frequency oscillations of the perturbation magnetic field, in the Pc5 range, interpreted in terms of a motion of quasi-stationary mesoscale field-aligned currents (FACs). Ground magnetic pulsations in the Ps6 range suggest that the Cluster observations are the high-altitude counterpart of the drifting auroral undulations, whose features thus can be explored closely. While multiscale minimum variance analysis provides information on the planarity, orientation, and scale of the FAC structures, the conjugate data from FAST and from the ground stations can be used to resolve also the azimuthal motion. A noteworthy feature of this event, revealed by the Cluster observations, is the apparent relaxation of the twisted magnetic flux tubes, from a sequence of 2-D current filaments to an undulated current sheet, on a timescale of about 10 min. This timescale appears to be consistent with the drift mirror instability in the inner magnetosphere, mapping to the equatorward side of the oval, or the Kelvin-Helmholtz instability related to bursty bulk flows farther downtail, mapping to the poleward side of the oval. However, more work is needed and a better event statistics, to confirm these tentative mechanisms as sources of Ω-like auroral undulations during late <span class="hlt">substorm</span> recovery.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/121260','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/121260"><span>Electrodynamic parameters in the nighttime sector during auroral <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fujii, R.; Hoffman, A.; Anderson, P.C.</p> <p>1994-04-01</p> <p>The characteristics of the large-scale electrodynamic parameters, field-aligned currents (FACs), electric fields, and electron precipitation, which are associated with auroral <span class="hlt">substorm</span> events in the nighttime sector, have been obtained through a unique analysis which places the ionospheric measurements of these parameters into the context of a generic <span class="hlt">substorm</span> determined from global auroral images. A generic bulge-type auroral emission region has been deduced from auroral images taken by the Dynamics Explorer 1 (DE 1) satellite during a number of isolated <span class="hlt">substorms</span>, and the form has been divided into six sectors, based on the peculiar emission characteristics in each vector: west of bulge, surge horn, surge, middle surge, eastern bulge, and east of bulge. By comparing the location of passes of the Dynamics Explorer 2 (DE 2) satellite to the simultaneously obtained auroral images, each pass is placed onto the generic aurora. The organization of DE 2 data in this way has systematically clarified peculiar characteristics in the electrodynamic parameters. An upward net current mainly appears in the surge, with little net current in the surge horn and the west of bulge. Near the poleward boundary of the expanding auroral bulge, a pair of oppositely directed FAC sheets is observed, with the downward FAC on the poleward side. This downward FAC and most of the upward FAC in the surge and the middle surge are associated with narrow, intense antisunward convection, corresponding to an equatorward directed spikelike electric field. This pair of currents decreases in amplitude and latitudinal width toward dusk in the surge and the west of bulge, and the region 1 and 2 FACs become embedded in the sunward convection region. The upward FAC region associated with the spikelike field on the poleward edge of the bulge coincides well with intense electron precipitation and aurora appearing in this western and poleward portion of the bulge. 44 refs., 14 figs., 2 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4497481','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4497481"><span>Quantitative maps of geomagnetic perturbation vectors during <span class="hlt">substorm</span> onset and recovery</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Pothier, N M; Weimer, D R; Moore, W B</p> <p>2015-01-01</p> <p>We have produced the first series of spherical harmonic, numerical maps of the time-dependent surface perturbations in the Earth's magnetic field following the onset of <span class="hlt">substorms</span>. Data from 124 ground magnetometer stations in the Northern Hemisphere at geomagnetic latitudes above 33° were used. Ground station data averaged over 5 min intervals covering 8 years (1998–2005) were used to construct pseudo auroral upper, auroral lower, and auroral electrojet (AU*, AL*, and AE*) indices. These indices were used to generate a list of <span class="hlt">substorms</span> that extended from 1998 to 2005, through a combination of automated processing and visual checks. Events were sorted by interplanetary magnetic field (IMF) orientation (at the Advanced Composition Explorer (ACE) satellite), dipole tilt angle, and <span class="hlt">substorm</span> magnitude. Within each category, the events were aligned on <span class="hlt">substorm</span> onset. A spherical cap harmonic analysis was used to obtain a least error fit of the <span class="hlt">substorm</span> disturbance patterns at 5 min intervals up to 90 min after onset. The fits obtained at onset time were subtracted from all subsequent fits, for each group of <span class="hlt">substorm</span> events. Maps of the three vector components of the averaged magnetic perturbations were constructed to show the effects of <span class="hlt">substorm</span> currents. These maps are produced for several specific ranges of values for the peak |AL*| index, IMF orientation, and dipole tilt angle. We demonstrate an influence of the dipole tilt angle on the response to <span class="hlt">substorms</span>. Our results indicate that there are downward currents poleward and upward currents just equatorward of the peak in the <span class="hlt">substorms</span>' westward electrojet. Key Points Show quantitative maps of ground geomagnetic perturbations due to <span class="hlt">substorms</span> Three vector components mapped as function of time during onset and recovery Compare/contrast results for different tilt angle and sign of IMF Y-component PMID:26167445</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5014235','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5014235"><span>What effect do <span class="hlt">substorms</span> have on the content of the radiation belts?</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rae, I. J.; Murphy, K. R.; Freeman, M. P.; Huang, C.‐L.; Spence, H. E.; Boyd, A. J.; Coxon, J. C.; Jackman, C. M.; Kalmoni, N. M. E.; Watt, C. E. J.</p> <p>2016-01-01</p> <p>Abstract <span class="hlt">Substorms</span> are fundamental and dynamic processes in the magnetosphere, converting captured solar wind magnetic energy into plasma energy. These <span class="hlt">substorms</span> have been suggested to be a key driver of energetic electron enhancements in the outer radiation belts. <span class="hlt">Substorms</span> inject a keV “seed” population into the inner magnetosphere which is subsequently energized through wave‐particle interactions up to relativistic energies; however, the extent to which <span class="hlt">substorms</span> enhance the radiation belts, either directly or indirectly, has never before been quantified. In this study, we examine increases and decreases in the total radiation belt electron content (TRBEC) following <span class="hlt">substorms</span> and geomagnetically quiet intervals. Our results show that the radiation belts are inherently lossy, shown by a negative median change in TRBEC at all intervals following <span class="hlt">substorms</span> and quiet intervals. However, there are up to 3 times as many increases in TRBEC following <span class="hlt">substorm</span> intervals. There is a lag of 1–3 days between the <span class="hlt">substorm</span> or quiet intervals and their greatest effect on radiation belt content, shown in the difference between the occurrence of increases and losses in TRBEC following <span class="hlt">substorms</span> and quiet intervals, the mean change in TRBEC following <span class="hlt">substorms</span> or quiet intervals, and the cross correlation between SuperMAG AL (SML) and TRBEC. However, there is a statistically significant effect on the occurrence of increases and decreases in TRBEC up to a lag of 6 days. Increases in radiation belt content show a significant correlation with SML and SYM‐H, but decreases in the radiation belt show no apparent link with magnetospheric activity levels. PMID:27656336</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27656336','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27656336"><span>What effect do <span class="hlt">substorms</span> have on the content of the radiation belts?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Forsyth, C; Rae, I J; Murphy, K R; Freeman, M P; Huang, C-L; Spence, H E; Boyd, A J; Coxon, J C; Jackman, C M; Kalmoni, N M E; Watt, C E J</p> <p>2016-07-01</p> <p><span class="hlt">Substorms</span> are fundamental and dynamic processes in the magnetosphere, converting captured solar wind magnetic energy into plasma energy. These <span class="hlt">substorms</span> have been suggested to be a key driver of energetic electron enhancements in the outer radiation belts. <span class="hlt">Substorms</span> inject a keV "seed" population into the inner magnetosphere which is subsequently energized through wave-particle interactions up to relativistic energies; however, the extent to which <span class="hlt">substorms</span> enhance the radiation belts, either directly or indirectly, has never before been quantified. In this study, we examine increases and decreases in the total radiation belt electron content (TRBEC) following <span class="hlt">substorms</span> and geomagnetically quiet intervals. Our results show that the radiation belts are inherently lossy, shown by a negative median change in TRBEC at all intervals following <span class="hlt">substorms</span> and quiet intervals. However, there are up to 3 times as many increases in TRBEC following <span class="hlt">substorm</span> intervals. There is a lag of 1-3 days between the <span class="hlt">substorm</span> or quiet intervals and their greatest effect on radiation belt content, shown in the difference between the occurrence of increases and losses in TRBEC following <span class="hlt">substorms</span> and quiet intervals, the mean change in TRBEC following <span class="hlt">substorms</span> or quiet intervals, and the cross correlation between SuperMAG AL (SML) and TRBEC. However, there is a statistically significant effect on the occurrence of increases and decreases in TRBEC up to a lag of 6 days. Increases in radiation belt content show a significant correlation with SML and SYM-H, but decreases in the radiation belt show no apparent link with magnetospheric activity levels.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSM43A2484Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSM43A2484Y"><span><span class="hlt">Substorm</span> Events from Observations of Energetic Particle Injections at Geosynchronous Orbit</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yakymenko, K.; Borovsky, J.</p> <p>2016-12-01</p> <p>We present a new algorithm for identification of <span class="hlt">substorm</span> events based on observation that the specific entropy S = T/n^{2/3} of energetic electron population at geosynchronous orbit decreases significantly when a fresh injection of electrons occurs. The time of injection events is refined by exploring the energy dispersion in the injected cluster of particles. More than 35 years of observations from CPA and SOPA instruments on board of the LANL geosynchronous satellites are analyzed and list of <span class="hlt">substorm</span> events is created. The list is compared with various <span class="hlt">substorm</span> onset lists identified from three other sets of data: SuperMAG index, Midlatitude Positive Bay index, and global auroral images. It is established that different data sets and algorithms yield different sets of events. We show that majority of events identified from ground-based magnetometer data by various known from the literature algorithms are intensifications of an ongoing <span class="hlt">substorm</span> event rather then true <span class="hlt">substorm</span> onsets. Difficulties and pitfalls in identification of <span class="hlt">substorm</span> events from different data sets are discussed. A comprehensive statistical study of the occurrence rate and recurrence time of magnetospheric <span class="hlt">substorms</span> versus parameters of solar-wind plasma passing the Earth,versus the level of geomagnetic activity, and time through three solar cycles was performed. <span class="hlt">Substorm</span> occurrence rates were studied in 70 high-speed-stream-driven storms: the rate is anomalously low in the calms before the storms, the rate increases rapidly at storm onset, and the rate is sustained at high levels for days through the high speed streams and into the trailing edges. <span class="hlt">Substorm</span> occurrence rates were studied in 47 CME-sheath-driven storms wherein the rate jumps up as the interplanetary shock passes the Earth and is sustained into the sheath. The passage of an interplanetary shock does not itself produce a <span class="hlt">substorm</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26167445','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26167445"><span>Quantitative maps of geomagnetic perturbation vectors during <span class="hlt">substorm</span> onset and recovery.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pothier, N M; Weimer, D R; Moore, W B</p> <p>2015-02-01</p> <p>We have produced the first series of spherical harmonic, numerical maps of the time-dependent surface perturbations in the Earth's magnetic field following the onset of <span class="hlt">substorms</span>. Data from 124 ground magnetometer stations in the Northern Hemisphere at geomagnetic latitudes above 33° were used. Ground station data averaged over 5 min intervals covering 8 years (1998-2005) were used to construct pseudo auroral upper, auroral lower, and auroral electrojet (AU*, AL*, and AE*) indices. These indices were used to generate a list of <span class="hlt">substorms</span> that extended from 1998 to 2005, through a combination of automated processing and visual checks. Events were sorted by interplanetary magnetic field (IMF) orientation (at the Advanced Composition Explorer (ACE) satellite), dipole tilt angle, and <span class="hlt">substorm</span> magnitude. Within each category, the events were aligned on <span class="hlt">substorm</span> onset. A spherical cap harmonic analysis was used to obtain a least error fit of the <span class="hlt">substorm</span> disturbance patterns at 5 min intervals up to 90 min after onset. The fits obtained at onset time were subtracted from all subsequent fits, for each group of <span class="hlt">substorm</span> events. Maps of the three vector components of the averaged magnetic perturbations were constructed to show the effects of <span class="hlt">substorm</span> currents. These maps are produced for several specific ranges of values for the peak |AL*| index, IMF orientation, and dipole tilt angle. We demonstrate an influence of the dipole tilt angle on the response to <span class="hlt">substorms</span>. Our results indicate that there are downward currents poleward and upward currents just equatorward of the peak in the <span class="hlt">substorms</span>' westward electrojet. Show quantitative maps of ground geomagnetic perturbations due to <span class="hlt">substorms</span> Three vector components mapped as function of time during onset and recovery Compare/contrast results for different tilt angle and sign of IMF Y-component.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/897989','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/897989"><span>Nucleation and <span class="hlt">growth</span> of the Alpha-Prime <span class="hlt">Phase</span> martensitic <span class="hlt">phase</span> in Pu-Ga Alloys</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Blobaum, K M; Krenn, C R; Wall, M A; Massalski, T B; Schwartz, A J</p> <p>2005-02-09</p> <p>In a Pu-2.0 at% Ga alloy, it is observed experimentally that the amount of the martensitic alpha-prime product formed upon cooling the metastable delta <span class="hlt">phase</span> below the martensite burst temperature (M{sub b}) is a function of the holding temperature and holding time of a prior conditioning (''annealing'') treatment. Before subjecting a sample to a cooling and heating cycle to form and revert the alpha-prime <span class="hlt">phase</span>, it was first homogenized for 8 hours at 375 C to remove any microstructural memory of prior transformations. Subsequently, conditioning was carried out in a differential scanning calorimeter apparatus at temperatures in the range between -50 C and 370 C for periods of up to 70 hours to determine the holding time and temperature that produced the largest volume fraction of alpha-prime upon subsequent cooling. Using transformation peak areas (i.e., the heats of transformation) as a measure of the amount of alpha-prime formed, the largest amount of alpha-prime was obtained following holding at 25 C for at prime least 6 hours. Additional time at 25 C, up to 70 hours, did not increase the amount of subsequent alpha-prime formation. At 25 C, the Pu-2.0 at% Ga alloy is below the eutectoid transformation temperature in the <span class="hlt">phase</span> diagram and the expected equilibrium <span class="hlt">phases</span> are {alpha} and Pu{sub 3}Ga, although a complete eutectoid decomposition of delta to these <span class="hlt">phases</span> is expected to be extremely slow. It is proposed here that the influence of the conditioning treatment can be attributed to the activation of alpha-<span class="hlt">phase</span> embryos in the matrix as a beginning step toward the eutectoid decomposition, and we discuss the effects of spontaneous self-irradiation accompanying the Pu radioactive decay on the activation process. Subsequently, upon cooling, certain embryos appear to be active as sites for the burst <span class="hlt">growth</span> of martensitic alpha-prime particles, and their amount, distribution, and potency appear to contribute to the total amount of martensitic product formed. A</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3575234','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3575234"><span>Shewanella oneidensis Hfq promotes exponential <span class="hlt">phase</span> <span class="hlt">growth</span>, stationary <span class="hlt">phase</span> culture density, and cell survival</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>2013-01-01</p> <p>Background Hfq is an RNA chaperone protein that has been broadly implicated in sRNA function in bacteria. Here we describe the construction and characterization of a null allele of the gene that encodes the RNA chaperone Hfq in Shewanella oneidensis strain MR-1, a dissimilatory metal reducing bacterium. Results Loss of hfq in S. oneidensis results in a variety of mutant phenotypes, all of which are fully complemented by addition of a plasmid-borne copy of the wild type hfq gene. Aerobic cultures of the hfq∆ mutant grow more slowly through exponential <span class="hlt">phase</span> than wild type cultures, and hfq∆ cultures reach a terminal cell density in stationary <span class="hlt">phase</span> that is ~2/3 of that observed in wild type cultures. We have observed a similar <span class="hlt">growth</span> phenotype when the hfq∆ mutant is cultured under anaerobic conditions with fumarate as the terminal electron acceptor, and we have found that the hfq∆ mutant is defective in Cr(VI) reduction. Finally, the hfq∆ mutant exhibits a striking loss of colony forming units in extended stationary <span class="hlt">phase</span> and is highly sensitive to oxidative stress induced by H2O2 or methyl viologen (paraquat). Conclusions The hfq mutant in S. oneidensis exhibits pleiotropic phenotypes, including a defect in metal reduction. Our results also suggest that hfq mutant phenotypes in S. oneidensis may be at least partially due to increased sensitivity to oxidative stress. PMID:23394078</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=177338','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=177338"><span><span class="hlt">Growth</span> <span class="hlt">phase</span>-dependent induction of stationary-<span class="hlt">phase</span> promoters of Escherichia coli in different gram-negative bacteria.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Miksch, G; Dobrowolski, P</p> <p>1995-01-01</p> <p>RSF1010-derived plasmids carrying a fusion of a promoterless lacZ gene with the sigma s-dependent <span class="hlt">growth</span> <span class="hlt">phase</span>-regulated promoters of Escherichia coli, bolAp1 and fic, were constructed. The plasmids were mobilized into the gram-negative bacterial species Acetobacter methanolicus, Xanthomonas campestris, Pseudomonas putida, and Rhizobium meliloti. The beta-galactosidase activities of bacterial cultures were determined during exponential and stationary <span class="hlt">growth</span> <span class="hlt">phases</span>. Transcriptional activation of the fic promoter in the different bacteria was <span class="hlt">growth</span> <span class="hlt">phase</span> dependent as in E. coli and was initiated generally during the transition to stationary <span class="hlt">phase</span>. The induction of the bolA promoter was also <span class="hlt">growth</span> <span class="hlt">phase</span> dependent in the bacteria tested. While the expression in E. coli and R. meliloti was initiated during the transition from exponential to stationary <span class="hlt">phase</span>, the induction in A. methanolicus, P. putida, and X. campestris started some hours after stationary <span class="hlt">growth</span> <span class="hlt">phase</span> was reached. In all the species tested, DNA fragments hybridizing with the rpoS gene of E. coli were detected. The results show that in different gram-negative bacteria, stationary-<span class="hlt">phase</span>-specific sigma factors which are structurally and functionally homologous to sigma s and are able to recognize the promoter sequences of both bolA and fic exist. PMID:7665531</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930060114&hterms=disruption&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Ddisruption','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930060114&hterms=disruption&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Ddisruption"><span>Simultaneous observation of the poleward expansion of <span class="hlt">substorm</span> electrojet activity and the tailward expansion of current sheet disruption in the near-earth magnetotail</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lopez, R. E.; Koskinen, H. E. J.; Pulkkinen, T. I.; Bosinger, T.; Mcentire, R. W.; Potemra, T. A.</p> <p>1993-01-01</p> <p>A <span class="hlt">substorm</span> that occurred on 7 June 1985 at 2209 UT for which simultaneous measurements from ground stations and CCE are available is considered. The event occurred during a close conjunction between CCE, the EISCAT magnetometer cross, and the STARE radar, allowing a detailed comparison of satellite and ground-based data. Two discrete activations took place during the first few minutes of this <span class="hlt">substorm</span>: the expansion <span class="hlt">phase</span> onset at 2209 UT and an intensification at 2212 UT, corresponding to a poleward expansion of activity. The energetic particle data indicate that the active region of the magnetotail during the 2212 UT intensification was located tailward of the active region at 2209 UT. This is direct evidence for a correspondence between tailward expansion of localized activity in the near-earth magnetotail (current disruption and particle energization) and poleward expansion of activity (electrojet formation) in the ionosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MS%26E..170a2020G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MS%26E..170a2020G"><span><span class="hlt">Phase</span> field modelling on the <span class="hlt">growth</span> dynamics of double voids of different sizes during czochralski silicon crystal <span class="hlt">growth</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guan, X. J.; Wang, J.</p> <p>2017-02-01</p> <p>To investigate their dynamics and interaction mechanisms, the <span class="hlt">growth</span> process of the two voids with different sizes during Czochralski silicon crystal <span class="hlt">growth</span> were simulated by use of an established <span class="hlt">phase</span> field model and its corresponding program code. On the basis of the several <span class="hlt">phase</span> field numerical simulation cases, the evolution laws of the double voids were acquired as follows: the <span class="hlt">phase</span> field model is capable to simulate the <span class="hlt">growth</span> process of double voids with different sizes; there are two modes of their <span class="hlt">growth</span>, that is, either mutual integration or competitive <span class="hlt">growth</span>; the exact moment of their fusion can be also captured, and it is τ of 7.078 (simulation time step of 14156) for the initial vacancy concentration of 0.02 and the initial space between two void centers of 44Δx.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM53A..02L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM53A..02L"><span>Relativistic Electron Enhancements at GEO: Magnetic Storms vs. <span class="hlt">Substorms</span></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.; Kim, H. J.; Pinto, V. A.; Wang, C. P.; Kim, K. C.</p> <p>2015-12-01</p> <p>We find evidence that magnetic storms are not only unnecessary for relativistic electron enhancements at geosynchronous orbit (GEO) but also not directly relevant to the electron enhancements at GEO even if the enhancements are accompanied by magnetic storms. What is crucial for electron enhancements at GEO are sustained south-oriented or north-south fluctuating IMF Bz that drives sufficiently large <span class="hlt">substorm</span> activity and small solar wind density Nsw that likely leads to low loss rate of relativistic electrons to the ionosphere and/or to the magnetopause for an extended time period. Specifically, almost all the abrupt, large electron increases in our data set took place under the condition of average AE > 235 nT and average Nsw ≤ 5 cm-3. Examination of detailed time profiles clearly shows that electron flux at GEO starts to increase quite immediately with arrival of the right IMF and solar wind conditions, regardless of a magnetic storm, leaving the accompanied magnetic storms merely co-incident, while the prolonged, intense <span class="hlt">substorms</span> are critical.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20030062107','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20030062107"><span><span class="hlt">Substorm</span> Evolution in the Near-Earth Plasma Sheet</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Erickson, Gary M.</p> <p>2003-01-01</p> <p>The goal of this project is to determine precursors and signatures of local <span class="hlt">substorm</span> onset and how they evolve in the plasma sheet using the Geotail near-Earth database. This project is part of an ongoing investigation involving this PI, Nelson Maynard (Mission Research Corporation), and William Burke (AFRL) toward an empirical understanding of the onset and evolution of <span class="hlt">substorms</span>. The first year began with dissemination of our CRRES findings, which included an invited presentation and major publication. The Geotail investigation began with a partial survey of onset signature types at distances X less than 15 R(sub E) for the first five months (March-July 1995) of the Geotail near-Earth mission. During the second year, Geotail data from March 1995 to present were plotted. Various signatures at local onset were catalogued for the period through 1997. During this past year we performed a survey of current-disruption-like (CD-like) signatures at distances X less than or equal to 14 R(sub E) for the three years 1995-1997.</p> </li> </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/2007AGUFMSM51B0534K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFMSM51B0534K"><span>Relative Order of Auroral Transient Structure During <span class="hlt">Substorm</span> Activation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kozelov, B. V.; Rypdal, K.</p> <p>2007-12-01</p> <p>Variability of auroral structures is a manifestation of the magnetosphere-ionosphere plasma dynamics. During the last decade the complexity of magnetosphere-ionosphere plasma has been widely discussed in numerous papers. The most popular approaches are based on turbulence or/and self-organized criticality paradigms. However, there is no clear evidence that the dynamics during the discussed events is really organization, and not disorganization. The problem is that the magnetosphere-ionosphere system is an open non-equilibrium system, therefore classical thermodynamics is not directly applicable. Here we use an approach based on the S-theorem by Yu.L. Klimontovich. This approach allows us to compare the ordering which characterize the current (non- equilibrium) state of the system with experimental data. The considered characteristic is an analogy of entropy which has been extended to non- equilibrium states. Television observations of the auroral structure during <span class="hlt">substorm</span> activation at the Barentsburg observatory (Svalbard) have been used as a data set. Dependence of the ordering on the spatial scale has been analyzed. We found that the ordering of the aurora increases during the <span class="hlt">substorm</span> development. The same approach has been applied to data sets generated by cellular automata models. Evolution of the systems in time and dependence on external control parameters are compared and discussed. Acknowledgements. This work was supported by grant No 171076/V30 of the Norwegian Research Council and partly by the Division of Physical Sciences of Russian Academy of Science.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EP%26S...69..129N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EP%26S...69..129N"><span>Near-Earth plasma sheet boundary dynamics during <span class="hlt">substorm</span> dipolarization</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nakamura, Rumi; Nagai, Tsugunobu; Birn, Joachim; Sergeev, Victor A.; Le Contel, Olivier; Varsani, Ali; Baumjohann, Wolfgang; Nakamura, Takuma; Apatenkov, Sergey; Artemyev, Anton; Ergun, Robert E.; Fuselier, Stephen A.; Gershman, Daniel J.; Giles, Barbara J.; Khotyaintsev, Yuri V.; Lindqvist, Per-Arne; Magnes, Werner; Mauk, Barry; Russell, Christopher T.; Singer, Howard J.; Stawarz, Julia; Strangeway, Robert J.; Anderson, Brian; Bromund, Ken R.; Fischer, David; Kepko, Laurence; Le, Guan; Plaschke, Ferdinand; Slavin, James A.; Cohen, Ian; Jaynes, Allison; Turner, Drew L.</p> <p>2017-09-01</p> <p>We report on the large-scale evolution of dipolarization in the near-Earth plasma sheet during an intense (AL -1000 nT) <span class="hlt">substorm</span> on August 10, 2016, when multiple spacecraft at radial distances between 4 and 15 R E were present in the night-side magnetosphere. This global dipolarization consisted of multiple short-timescale (a couple of minutes) B z disturbances detected by spacecraft distributed over 9 MLT, consistent with the large-scale <span class="hlt">substorm</span> current wedge observed by ground-based magnetometers. The four spacecraft of the Magnetospheric Multiscale were located in the southern hemisphere plasma sheet and observed fast flow disturbances associated with this dipolarization. The high-time-resolution measurements from MMS enable us to detect the rapid motion of the field structures and flow disturbances separately. A distinct pattern of the flow and field disturbance near the plasma boundaries was found. We suggest that a vortex motion created around the localized flows resulted in another field-aligned current system at the off-equatorial side of the BBF-associated R1/R2 systems, as was predicted by the MHD simulation of a localized reconnection jet. The observations by GOES and Geotail, which were located in the opposite hemisphere and local time, support this view. We demonstrate that the processes of both Earthward flow braking and of accumulated magnetic flux evolving tailward also control the dynamics in the boundary region of the near-Earth plasma sheet.[Figure not available: see fulltext.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19720007674','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19720007674"><span>Electric field variations during <span class="hlt">substorms</span>: OGO-6 measurements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Heppner, J. P.</p> <p>1972-01-01</p> <p>The OGO-6 electric field measurements make it clear that the general pattern of high latitude electric fields in magnetic time-invariant latitude coordinates is not highly variable and that when unusual variations, or field distributions, occur they are relatively isolated in time and spatial extent. Thus, electric field changes on a global scale cannot, in general, be evoked as a direct cause of <span class="hlt">substorms</span>. Polar traverses along the 18(h) to 6(h) magnetic time meridian show that the sum of potential drops across the evening auroral belt and morning auroral belt approximately equals the potential drop across the polar cap. The integrated polar cap potential drop ranges from 20 to 100 keV and values in the center of this range are most common under conditions of moderate magnetic disturbance. Roughly near 18(h) magnetic local time, a latitudinally narrow strip at the transition between auroral belt and polar cap fields exhibits unusually large field fluctuations immediately following the sudden onset of a negative bay at later magnetic local times. It appears likely that this spatially isolated correlation is related to an effect rather than a cause of <span class="hlt">substorm</span> enhancement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JSWSC...6A..37E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JSWSC...6A..37E"><span>Effects of <span class="hlt">substorm</span> electrojet on declination along concurrent geomagnetic latitudes in the northern auroral zone</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Edvardsen, Inge; Johnsen, Magnar G.; Løvhaug, Unni P.</p> <p>2016-10-01</p> <p>The geomagnetic field often experiences large fluctuations, especially at high latitudes in the auroral zones. We have found, using simulations, that there are significant differences in the <span class="hlt">substorm</span> signature, in certain coordinate systems, as a function of longitude. This is confirmed by the analysis of real, measured data from comparable locations. Large geomagnetic fluctuations pose challenges for companies involved in resource exploitation since the Earth's magnetic field is used as the reference when navigating drilling equipment. It is widely known that geomagnetic activity increases with increasing latitude and that the largest fluctuations are caused by <span class="hlt">substorms</span>. In the auroral zones, <span class="hlt">substorms</span> are common phenomena, occurring almost every night. In principle, the magnitude of geomagnetic disturbances from two identical <span class="hlt">substorms</span> along concurrent geomagnetic latitudes around the globe, at different local times, will be the same. However, the signature of a <span class="hlt">substorm</span> will change as a function of geomagnetic longitude due to varying declination, dipole declination, and horizontal magnetic field along constant geomagnetic latitudes. To investigate and quantify this, we applied a simple <span class="hlt">substorm</span> current wedge model in combination with a dipole representation of the Earth's magnetic field to simulate magnetic <span class="hlt">substorms</span> of different morphologies and local times. The results of these simulations were compared to statistical data from observatories and are discussed in the context of resource exploitation in the Arctic. We also attempt to determine and quantify areas in the auroral zone where there is a potential for increased space weather challenges compared to other areas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JGRA..113.0C08B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JGRA..113.0C08B"><span>Auroral medium frequency burst radio emission associated with the 23 March 2007 THEMIS study <span class="hlt">substorm</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bunch, N. L.; Labelle, J.; Weatherwax, A. T.; Hughes, J. M.</p> <p>2008-01-01</p> <p>Auroral medium frequency (MF) burst is an impulsive auroral radio emission associated with <span class="hlt">substorm</span> onset detected by ground-based instruments between 1.3 and 4.5 MHz. On 23 March 2007 an MF burst emission was detected by the Dartmouth radio interferometer located near Toolik Lake, Alaska. This emission temporally coincides with the onset of the 23 March 2007 Time History of Events and Macroscale Interactions during <span class="hlt">Substorms</span> (THEMIS) study <span class="hlt">substorm</span>. Directions of arrival computed using the Dartmouth radio interferometer for this event also coincide spatially with the location of the expanding auroral arcs to the south observed by the all-sky imager at Fort Yukon, Alaska. This observation represents the first example of a direction of arrival measurement for MF burst. It strongly supports the association of MF burst with intense auroral arcs accompanying <span class="hlt">substorm</span> onset. The direction of arrival of the MF burst is consistent with the direction to the eastern edge of the <span class="hlt">substorm</span> onset location determined by multiple data sets during this <span class="hlt">substorm</span> and suggests that location of MF burst radio emissions may be an effective method of locating <span class="hlt">substorm</span> onsets, much as radio atmospherics are used to locate lightning.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.1197P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.1197P"><span>Quantitative maps of geomagnetic perturbation vectors during <span class="hlt">substorm</span> onset and recovery</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pothier, N. M.; Weimer, D. R.; Moore, W. B.</p> <p>2015-02-01</p> <p>We have produced the first series of spherical harmonic, numerical maps of the time-dependent surface perturbations in the Earth's magnetic field following the onset of <span class="hlt">substorms</span>. Data from 124 ground magnetometer stations in the Northern Hemisphere at geomagnetic latitudes above 33° were used. Ground station data averaged over 5 min intervals covering 8 years (1998-2005) were used to construct pseudo auroral upper, auroral lower, and auroral electrojet (AU*, AL*, and AE*) indices. These indices were used to generate a list of <span class="hlt">substorms</span> that extended from 1998 to 2005, through a combination of automated processing and visual checks. Events were sorted by interplanetary magnetic field (IMF) orientation (at the Advanced Composition Explorer (ACE) satellite), dipole tilt angle, and <span class="hlt">substorm</span> magnitude. Within each category, the events were aligned on <span class="hlt">substorm</span> onset. A spherical cap harmonic analysis was used to obtain a least error fit of the <span class="hlt">substorm</span> disturbance patterns at 5 min intervals up to 90 min after onset. The fits obtained at onset time were subtracted from all subsequent fits, for each group of <span class="hlt">substorm</span> events. Maps of the three vector components of the averaged magnetic perturbations were constructed to show the effects of <span class="hlt">substorm</span> currents. These maps are produced for several specific ranges of values for the peak |AL*| index, IMF orientation, and dipole tilt angle. We demonstrate an influence of the dipole tilt angle on the response to <span class="hlt">substorms</span>. Our results indicate that there are downward currents poleward and upward currents just equatorward of the peak in the <span class="hlt">substorms</span>' westward electrojet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=236582','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=236582"><span>Microarray and functional analysis of <span class="hlt">growth-phase</span> dependent gene regulation in Bordetella bronchiseptica</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p><span class="hlt">Growth-phase</span> dependent gene regulation has recently been demonstrated to occur in B. pertussis, with many transcripts, including known virulence factors, significantly decreasing during the transition from logarithmic to stationary-<span class="hlt">phase</span> <span class="hlt">growth</span>. Given that B. pertussis is thought to have derived fro...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhPl...23e2713W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhPl...23e2713W"><span>A scheme for reducing deceleration-<span class="hlt">phase</span> Rayleigh-Taylor <span class="hlt">growth</span> in inertial confinement fusion implosions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, L. F.; Ye, W. H.; Wu, J. F.; Liu, Jie; Zhang, W. Y.; He, X. T.</p> <p>2016-05-01</p> <p>It is demonstrated that the <span class="hlt">growth</span> of acceleration-<span class="hlt">phase</span> instabilities in inertial confinement fusion implosions can be controlled, especially in the high-foot implosions [O. A. Hurricane et al., Phys. Plasmas 21, 056314 (2014)] on the National Ignition Facility. However, the excessive <span class="hlt">growth</span> of the deceleration-<span class="hlt">phase</span> instabilities can still destroy the hot spot ignition. A scheme is proposed to retard the deceleration-<span class="hlt">phase</span> Rayleigh-Taylor instability <span class="hlt">growth</span> by shock collision near the waist of the inner shell surface. Two-dimensional radiation hydrodynamic simulations confirm the improved deceleration-<span class="hlt">phase</span> hot spot stability properties without sacrificing the fuel compression.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22600090','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22600090"><span>A scheme for reducing deceleration-<span class="hlt">phase</span> Rayleigh–Taylor <span class="hlt">growth</span> in inertial confinement fusion implosions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wang, L. F. Ye, W. H.; Liu, Jie; Wu, J. F.; Zhang, W. Y.; He, X. T.</p> <p>2016-05-15</p> <p>It is demonstrated that the <span class="hlt">growth</span> of acceleration-<span class="hlt">phase</span> instabilities in inertial confinement fusion implosions can be controlled, especially in the high-foot implosions [O. A. Hurricane et al., Phys. Plasmas 21, 056314 (2014)] on the National Ignition Facility. However, the excessive <span class="hlt">growth</span> of the deceleration-<span class="hlt">phase</span> instabilities can still destroy the hot spot ignition. A scheme is proposed to retard the deceleration-<span class="hlt">phase</span> Rayleigh–Taylor instability <span class="hlt">growth</span> by shock collision near the waist of the inner shell surface. Two-dimensional radiation hydrodynamic simulations confirm the improved deceleration-<span class="hlt">phase</span> hot spot stability properties without sacrificing the fuel compression.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19740029880&hterms=ISIS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DISIS','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19740029880&hterms=ISIS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DISIS"><span>Equatorward shift of the cleft during magnetospheric <span class="hlt">substorms</span> as observed by Isis 1</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Yasuhara, F.; Akasofu, S.-I.; Winningham, J. D.; Heikkila , W. J.</p> <p>1973-01-01</p> <p>Isis 1 satellite observations of the cleft position during magnetospheric <span class="hlt">substorms</span> show that the cleft shifts equatorward as the interplanetary B sub z component turns southward and <span class="hlt">substorm</span> activity increases and that it shifts back toward higher latitudes as <span class="hlt">substorm</span> activity subsides and B sub z returns northward. Also, unusually low latitudes for the cleft (less than 70 deg invariant latitude) were found during geomagnetic storms with significant Dst values and large negative B sub z values. Significant shifts occur in the cleft location with no accompanying effect seen in the AE index; however, B sub z is observed to be southward during these periods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19740029880&hterms=Isis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DIsis','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19740029880&hterms=Isis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DIsis"><span>Equatorward shift of the cleft during magnetospheric <span class="hlt">substorms</span> as observed by Isis 1</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Yasuhara, F.; Akasofu, S.-I.; Winningham, J. D.; Heikkila , W. J.</p> <p>1973-01-01</p> <p>Isis 1 satellite observations of the cleft position during magnetospheric <span class="hlt">substorms</span> show that the cleft shifts equatorward as the interplanetary B sub z component turns southward and <span class="hlt">substorm</span> activity increases and that it shifts back toward higher latitudes as <span class="hlt">substorm</span> activity subsides and B sub z returns northward. Also, unusually low latitudes for the cleft (less than 70 deg invariant latitude) were found during geomagnetic storms with significant Dst values and large negative B sub z values. Significant shifts occur in the cleft location with no accompanying effect seen in the AE index; however, B sub z is observed to be southward during these periods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27485629','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27485629"><span>Investigation of <span class="hlt">Growth</span> <span class="hlt">Phase</span>-Dependent Acid Tolerance in Bifidobacteria longum BBMN68.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jin, Junhua; Song, Jingyi; Ren, Fazheng; Zhang, Hongxing; Xie, Yuanhong; Ma, Jingsheng; Li, Xue</p> <p>2016-11-01</p> <p>The underlying mechanisms imparting the <span class="hlt">growth</span> <span class="hlt">phase</span>-dependent acid tolerance have not been extensively investigated. In this study, we compared the acid resistance of the Bifidobacterium longum strain BBMN68 from different <span class="hlt">growth</span> <span class="hlt">phases</span> at lethal pH values (pH 2.5, 3.0, and 3.5), and analyzed the activity of H(+)-ATPase, the composition of fatty acids, and the mRNA abundance of ffh, uvrA, recA, lexA, groES, and dnaK in cells from different <span class="hlt">growth</span> <span class="hlt">phases</span>. The results indicated that the survival rates of cells from early stationary (ES) and late stationary (LS) <span class="hlt">growth</span> <span class="hlt">phases</span> at lethal pH values were significantly higher than those of exponential <span class="hlt">growth</span> <span class="hlt">phase</span> cells. Our findings indicated that by inducing a continuously auto-acidizing environment during cell <span class="hlt">growth</span>, the acid resistance of ES and LS cells was strengthened. The higher activity of H(+)-ATPase, the decrease in unsaturated fatty acids, and the increased expression of genes involved in DNA repair and protein protection in the cells in stationary <span class="hlt">growth</span> <span class="hlt">phase</span> were all implicated in the significantly increased acid resistance of ES and LS cells compared with exponential <span class="hlt">growth</span> <span class="hlt">phase</span> cells of the B. longum strain BBMN68.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950029563&hterms=FACS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DFACS','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950029563&hterms=FACS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DFACS"><span>Electrodynamic parameters in the nighttime sector during auroral <span class="hlt">substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fujii, R.; Hoffman, R. A.; Anderson, P. C.; Craven, J. D.; Sugiura, M.; Frank, L. A.; Maynard, N. C.</p> <p>1994-01-01</p> <p>The characteristics of the large-scale electrodynamic parameters, field-aligned currents (FACs), electric fields, and electron precipitation, which are associated with auroral <span class="hlt">substorm</span> events in the nighttime sector, have been obtained through a unique analysis which places the ionospheric measurements of these parameters into the context of a generic <span class="hlt">substorm</span> determined from global auroral images. A generic bulge-type auroral emission region has been deduced from auroral images taken by the Dynamics Explorer 1 (DE 1) satellite during a number of isolated <span class="hlt">substorms</span>, and the form has been divided into six sectors, based on the peculiar emission characteristics in each sector: west of bulge, surge horn, surge, middle surge, eastern bulge, and east of bulge. By comparing the location of passes of the Dynamics Explorer 2 (DE 2) satellite to the simultaneously obtained auroral images, each pass is placed onto the generic aurora. The organization of DE 2 data in this way has systematically clarified peculiar characteristics in the electrodynamic parameters. An upward net current mainly appears in the surge, with little net current in the surge horn and the west of bulge. The downward net current is distributed over wide longitudinal regions from the eastern bulge to the east of bulge. Near the poleward boundary of the expanding auroral bulge, a pair of oppositely directed FAC sheets is observed, with the downward FAC on the poleward side. This downward FAC and most of the upward FAC in the surge and the middle surge are assoc iated with narrow, intense antisunwqard convection, corresponding to an equatorward directed spikelike electric field. This pair of currents decreases in amplitude and latitudinal width toward dusk in the surge and the west of bulge, and the region 1 and 2 FACs become embedded in the sunward convection region. The upward FAC region associated with the spikelike field on the poleward edge of the bulge coincides well with intense electron</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1016129','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1016129"><span>Condensed <span class="hlt">phase</span> conversion and <span class="hlt">growth</span> of nanorods and other materials instead of from vapor</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Geohegan, David B.; Seals, Roland D.; Puretzky, Alex A.; Fan, Xudong</p> <p>2010-10-19</p> <p>Compositions, systems and methods are described for condensed <span class="hlt">phase</span> conversion and <span class="hlt">growth</span> of nanorods and other materials. A method includes providing a condensed <span class="hlt">phase</span> matrix material; and activating the condensed <span class="hlt">phase</span> matrix material to produce a plurality of nanorods by condensed <span class="hlt">phase</span> conversion and <span class="hlt">growth</span> from the condensed <span class="hlt">phase</span> matrix material instead of from vapor. The compositions are very strong. The compositions and methods provide advantages because they allow (1) formation rates of nanostructures necessary for reasonable production rates, and (2) the near net shaped production of component structures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20110015526&hterms=Latitude&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DLatitude','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20110015526&hterms=Latitude&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DLatitude"><span>Observations of a High-Latitude Stable Electron Auroral Emission at Approximately 16 MLT During a Large <span class="hlt">Substorm</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cattell, C.; Dombeck, J.; Preiwisch, A.; Thaller, S.; Vo, P.; Wilson, L. B., III; Wygant, J.; Mende, S. B.; Frey, H. U.; Ilie, R.; Lu, G.</p> <p>2011-01-01</p> <p>During an interval when the interplanetary magnetic field was large and primarily duskward and southward, a stable region of auroral emission was observed on 17 August 2001 by IMAGE at 16 magnetic local time, poleward of the main aurora, for 1 h, from before the onset of a large <span class="hlt">substorm</span> through the recovery <span class="hlt">phase</span>. In a region where ions showed the energy dispersion expected for the cusp, strong field \\aligned currents and Poynting flux were observed by Polar (at 1.8 RE in the Southern Hemisphere) as it transited field lines mapping to the auroral spot in the Northern Hemisphere. The data are consistent with the hypothesis that the long \\lasting electron auroral spot maps to the magnetopause region where reconnection was occurring. Under the assumption of conjugacy between the Northern and Southern hemispheres on these field lines, the Polar data suggest that the electrons on these field lines were accelerated by Alfven waves and/or a quasi \\static electric field, primarily at altitudes below a few RE since the in situ Poynting flux (mapped to 100 km) is comparable to the energy flux of the emission while the mapped in situ electron energy flux is much smaller. This event provides the first example of an emission due to electrons accelerated at low altitudes at the foot point of a region of quasi \\steady dayside reconnection. Cluster data in the magnetotail indicate that the Poynting flux from the reconnection region during this <span class="hlt">substorm</span> is large enough to account for the observed nightside aurora.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSM51B2486M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSM51B2486M"><span>A THEMIS Case Study of Pi2 Pulsations in the Magnetotail and on the Ground Before a <span class="hlt">Substorm</span> Onset</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miyashita, Y.; Angelopoulos, V.; Hiraki, Y.; Ieda, A.; Machida, S.</p> <p>2016-12-01</p> <p>Using THEMIS spacecraft and ground data, we studied low-frequency Pi2 pulsations in the magnetotail and on the ground just before a <span class="hlt">substorm</span> onset. A case study shows that a new compressional Pi2 pulsation was observed in the plasma sheet just earthward of the near-Earth reconnection site 4 min before initial auroral brightening or 2 min before auroral fading. The ion and magnetic pressure perturbations appeared to be partly in <span class="hlt">phase</span> at the beginning, indicating that the wave had fast mode. A similar wave was observed also tailward of the near-Earth reconnection site, although it occurred 4 min later. These waves may have been generated at the near-Earth reconnection site. On the ground, Pi2 pulsations were observed widely in the polar cap and at the auroral oval before initial auroral brightening and auroral fading, although the amplitudes were small, compared to those associated with auroral poleward expansion. There was a tendency that the waves were observed first in the polar cap near the initial auroral brightening site and then in the surrounding regions. Ionospheric convection began to be enhanced gradually 1 or 2 min after the Pi2 onsets. We discuss the causal relationship between the Pi2 pulsations in the magnetotail and on the ground as well as their role in <span class="hlt">substorm</span> triggering.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12379717','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12379717"><span>Staphylococcus aureus aconitase inactivation unexpectedly inhibits post-exponential-<span class="hlt">phase</span> <span class="hlt">growth</span> and enhances stationary-<span class="hlt">phase</span> survival.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Somerville, Greg A; Chaussee, Michael S; Morgan, Carrie I; Fitzgerald, J Ross; Dorward, David W; Reitzer, Lawrence J; Musser, James M</p> <p>2002-11-01</p> <p>Staphylococcus aureus preferentially catabolizes glucose, generating pyruvate, which is subsequently oxidized to acetate under aerobic <span class="hlt">growth</span> conditions. Catabolite repression of the tricarboxylic acid (TCA) cycle results in the accumulation of acetate. TCA cycle derepression coincides with exit from the exponential <span class="hlt">growth</span> <span class="hlt">phase</span>, the onset of acetate catabolism, and the maximal expression of secreted virulence factors. These data suggest that carbon and energy for post-exponential-<span class="hlt">phase</span> <span class="hlt">growth</span> and virulence factor production are derived from the catabolism of acetate mediated by the TCA cycle. To test this hypothesis, the aconitase gene was genetically inactivated in a human isolate of S. aureus, and the effects on physiology, morphology, virulence factor production, virulence for mice, and stationary-<span class="hlt">phase</span> survival were examined. TCA cycle inactivation prevented the post-exponential <span class="hlt">growth</span> <span class="hlt">phase</span> catabolism of acetate, resulting in premature entry into the stationary <span class="hlt">phase</span>. This phenotype was accompanied by a significant reduction in the production of several virulence factors and alteration in host-pathogen interaction. Unexpectedly, aconitase inactivation enhanced stationary-<span class="hlt">phase</span> survival relative to the wild-type strain. Aconitase is an iron-sulfur cluster-containing enzyme that is highly susceptible to oxidative inactivation. We speculate that reversible loss of the iron-sulfur cluster in wild-type organisms is a survival strategy used to circumvent oxidative stress induced during host-pathogen interactions. Taken together, these data demonstrate the importance of the TCA cycle in the life cycle of this medically important pathogen.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22154564','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22154564"><span>Hyperosmotic pressure on HEK 293 cells during the <span class="hlt">growth</span> <span class="hlt">phase</span>, but not the production <span class="hlt">phase</span>, improves adenovirus production.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shen, Chun Fang; Kamen, Amine</p> <p>2012-01-01</p> <p>Hyperosmotic stress has been widely explored as a means of improving specific antibody productivity in mammalian cell cultures. In contrast, a decrease in cell-specific productivity of adenovirus production has been reported in several studies in which virus production in HEK 293 cell cultures was conducted under hyperosmotic conditions. However, production of viral vectors and, in particular, adenoviral vectors is the result of two consecutive <span class="hlt">phases</span>: the <span class="hlt">growth</span> <span class="hlt">phase</span> and the virus production <span class="hlt">phase</span>. In this study, the singular and combined effects of osmolality on the <span class="hlt">phases</span> of cell <span class="hlt">growth</span> and virus production were evaluated in culture media with osmolalities ranging from 250 to 410mOsm. A two-factor, five-level full factorial design was used to investigate the effect of osmotic stress on cell physiology, as determined through the characterization of cell <span class="hlt">growth</span>, cell metabolism, cell viability, cell cycle, cell RNA and total protein content, and total virus yield/cell-specific virus productivity. Overall, the results show that the <span class="hlt">growth</span> of cells under hyperosmotic conditions induced favorable physiological states for viral production, and the specific virus productivity was improved by more than 11-fold when the medium's osmolality was increased from 250 to 410mOsm during the cell <span class="hlt">growth</span> <span class="hlt">phase</span>. Both hypo- and hyperosmotic stresses in the virus production <span class="hlt">phase</span> reduced virus productivity by as much as a factor of six. Optimal virus productivity was achieved by growing cells in media with an osmolality of 370mOsm or greater, followed by a virus production <span class="hlt">phase</span> at an osmolality of 290mOsm. Compared to standard culture and production conditions in isotonic media, the shift from high to low osmolality between the two <span class="hlt">phases</span> resulted in a two- to three-fold increase in virus yields. This hyperosmotic pressure effect on virus productivity was reproduced in five different commercial serum-free media. Crown Copyright © 2011. Published by Elsevier B.V. All rights</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM32B..07D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM32B..07D"><span><span class="hlt">Substorm</span> Onset: Getting the Sequence of Events Right</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Donovan, E.; Nishimura, Y.; Spanswick, E.; Kepko, L.</p> <p>2015-12-01</p> <p>New observations from THEMIS and complementary ground-based auroral observing programs have transformed our understanding of <span class="hlt">substorm</span> onset. As far as we have come, however, there are still great challenges that must be addressed. Determining the relative timing of the different events which comprise onset is perhaps key amongst these, but has proven to be particularly challenging. Here we use optical observations of the onset in white light (THEMIS-ASI) and the 630 nm "redline" (TREx/REGO) to explore the causal relationship between events preceding onset (seen indirectly via auroral streamers) and onset (seen via auroral brightening). To do this, we employ a new analysis technique, called the 'circogram', which focuses on the direction of propagation of information in sequences of auroral images.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920045465&hterms=IRM&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DIRM','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920045465&hterms=IRM&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DIRM"><span>Pressure changes in the plasma sheet during <span class="hlt">substorm</span> injections</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kistler, L. M.; Moebius, E.; Baumjohann, W.; Paschmann, G.; Hamilton, D. C.</p> <p>1992-01-01</p> <p>Data from the CHEM instrument on AMPTE CCE, data from the 3D plasma instrument and the SULEICA instrument on AMPTE IRM, and magnetometer data from both spacecraft are used to determine the particle pressure and total pressure as a function of radial distance in the plasma sheet for periods before and after the onset of <span class="hlt">substorm</span>-associated ion enhancements over the range 7-19 RE. Events were chosen that occurred during times of increasing magnetospheric activity, as determined by an increasing AE index, in which a sudden increase, or 'injection', of energetic particle flux is observed. It is shown that the simultaneous appearance of energetic particles and changes in the magnetic field results naturally from pressure balance and does not necessarily indicate that the local changing field is accelerating the particles.</p> </li> </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('https://ntrs.nasa.gov/search.jsp?R=19820036569&hterms=High+Altitude+Plasma+Instrument&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DHigh%2BAltitude%2BPlasma%2BInstrument','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820036569&hterms=High+Altitude+Plasma+Instrument&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DHigh%2BAltitude%2BPlasma%2BInstrument"><span>Plasma pitch angle distributions near the <span class="hlt">substorm</span> injection front</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Moore, T. E.; Arnoldy, R. L.</p> <p>1982-01-01</p> <p>ATS-6 spacecraft hot plasma instrument data obtained during January, 1980 is presented, which provides electron and ion pitch distributions in the vicinity of an earthward-propagating, <span class="hlt">substorm</span>-associated abrupt plasma change near synchronous orbit. Evidence is found of symmetric atmospheric source cones for few 100-eV electrons after front passage, supporting both (1) concept of atmospheric electron degradation of the hot, high-altitude plasma, and (2) the proposal that the injection front is a moving, precipitation-flow boundary between the hot plasma and the cooler plasma that has become spectrally degraded via interaction with the atmosphere. The enhanced hot plasma electron intensities appearing in association with front passage exhibit a modest, field-aligned anisotropy with minima at pitch angles characteristic of symmetric loss cones, consistent with mirror compression of the electrons on inward-collapsing field lines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19780068607&hterms=IMP&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DIMP','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19780068607&hterms=IMP&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DIMP"><span>Imp 6 measurements in the distant polar cusp during <span class="hlt">substorms</span></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.</p> <p>1978-01-01</p> <p>High time-resolution data from the magnetic field, plasma, energetic particle, and VLF wave experiments performed aboard Imp 6 in a study of the distant dayside cusp during <span class="hlt">substorms</span> are described. The cusp was studied when its location was slightly equatorward of its normal location and the geomagnetic dipole was tilted in the appropriate direction. The data support both reconnection and diffusion as methods of particle entry to the magnetosphere. The evidence (1) indicates an acceleration process to explain enhancements of 400 to 600-km/sec protons above their magnetosheath intensities, and (2) suggests convection of field lines over the polar cap as a means of explaining the lack of low-energy protons near the low-latitude boundary of the cusp. Magnetic field fluctuations, a perturbation vector, ion cyclotron waves, and an abrupt change in the intensity of both whistler waves and electrostatic waves are characterized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AdSpR..54.2549K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AdSpR..54.2549K"><span>Anthropogenic trigger of <span class="hlt">substorms</span> and energetic particles precipitations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kuznetsov, V. D.; Ruzhin, Yu. Ya.</p> <p>2014-12-01</p> <p>The high-frequency (HF) emission in near-Earth space from various powerful transmitters (radio communications, radars, broadcasting, universal time and navigation stations, etc.) form an integral part of the modern world that it cannot do without. In particular, special-purpose research facilities equipped with powerful HF transmitters are used successfully for plasma experiments and local modification of the ionosphere. In this work, we are using the results of a complex space-ground experiment to show that exposure of the subauroral region to HF emission can not only cause local changes in the ionosphere, but can also trigger processes in the magnetosphere-ionosphere system that result in intensive <span class="hlt">substorm</span> activity (precipitations of high-energy particles, aurorae, significant variations in the ionospheric parameters and, as a consequence, in radio propagation conditions).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110008578','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110008578"><span>Space Borne and Ground-Based Observations of Transient Processes Occurring Around <span class="hlt">Substorm</span> Onset</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kepko, L.; Spanswick, E.; Angelopoulos, V.; Donovan, E.</p> <p>2010-01-01</p> <p>The combined THEMIS five spacecraft in-situ and ground magnetic and visible camera arrays have advanced considerably our understanding of the causal relationship between midtail plasma flows, transient ionospheric features, and ground magnetic signatures. In particular recent work has shown a connection between equatorward moving visible ionospheric transients and <span class="hlt">substorm</span> onset, in both white-light and 6300 nm emissions. These observations, together with THEMIS in-situ measurements of bulk flows, provides strict constraints on the sequence of events leading to <span class="hlt">substorm</span> auroral onset.We first provide a brief summary of these observations, highlighting in particular areas where the two observations differ, and suggest reasons for the differences. Next, by combining the observed correlation of flow and Pi2 waveform with a unified model of global Pi2 generation and <span class="hlt">substorm</span> current wedge initiation we present a self-consistent description of the dynamical processes and communicative pathways that occur just prior to and during <span class="hlt">substorm</span> expansion onset.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E1097G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E1097G"><span>Observations of <span class="hlt">substorms</span> during storms connected with different sources in the solar wind</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guineva, Veneta; Despirak, Irina; Kozelov, Boris; Borovkov, Leonid</p> <p></p> <p>All-sky cameras data at Kola Peninsula from the 2012/2013 winter seasons have been used to study the variations of <span class="hlt">substorm</span> development under different conditions of the interplanetary medium. Solar wind and interplanetary magnetic field parameters were taken from OMNI data base. Using solar wind data for the examined periods, different solar wind streams were revealed: recurrent high-speed streams (RS) and magnetic clouds (MC). It is known that these solar wind structures are the sources of geomagnetic storms. In our study <span class="hlt">substorm</span> developments during storms with different origins and during quiet geomagnetic conditions were compared. <span class="hlt">Substorm</span> onset time and further development were verified by data of IMAGE magnetometers network and by data of all-sky cameras at Apatity and Lovozero. The particularities in the behaviour of <span class="hlt">substorms</span> observed by storms connected with solar wind recurrent streams and by magnetic clouds are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110013353','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110013353"><span>Recent Themis and Coordinated GBO Measurements of <span class="hlt">Substorm</span> Expansion Onset: Do We Finally Have an Answer?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kepko, Larry</p> <p>2011-01-01</p> <p>For nearly 30 years an often-times heated debate has engaged the <span class="hlt">substorm</span> community: Do <span class="hlt">substorms</span> begin with the formation of a new reconnection site in the midtail plasmasheet (the Near-Earth Neutral Line model) or do they begin near the transition region between stretched tail and dipolar field lines (the Current Disruption model). The THEMIS mission, with a coordinated suite of five in-situ spacecraft and ground observatories. has greatly extended our understanding of how <span class="hlt">substorms</span> initiate and evolve. But have the new data resolved the fundamental question? In this talk I review the last few year's of <span class="hlt">substorm</span> research, with an emphasis of how the THEMIS data have revolutionized our understanding.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014GeoRL..41.4449C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014GeoRL..41.4449C"><span>Electric currents of a <span class="hlt">substorm</span> current wedge on 24 February 2010</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Connors, Martin; McPherron, Robert L.; Anderson, Brian J.; Korth, Haje; Russell, Christopher T.; Chu, Xiangning</p> <p>2014-07-01</p> <p>The three-dimensional "<span class="hlt">substorm</span> current wedge" (SCW) was postulated by McPherron et al. (1973) to explain <span class="hlt">substorm</span> magnetic perturbations. The origin and coherence as a physical system of this important paradigm of modern space physics remained unclear, however, with progress hindered by gross undersampling, and uniqueness problems in data inversion. Complementing AMPERE (Active Magnetosphere and Planetary Electrodynamics Response Experiment) space-derived radial electric currents with ground magnetic data allowing us to determine currents from the ionosphere up, we overcome problems of uniqueness identified by Fukushima (1969, 1994). For a <span class="hlt">substorm</span> on 24 February 2010, we quantify SCW development consistently from ground and space data. Its westward electrojet carries 0.5 MA in the more poleward part of the auroral oval, in Region 1 (R1) sense spanning midnight. The evening sector electrojet also feeds into its upward current. We thus validate the SCW concept and obtain parameters needed for quantitative study of <span class="hlt">substorms</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19720021780','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19720021780"><span>Magnetic field signatures of <span class="hlt">substorms</span> on high latitudes field lines in the nighttime magnetosphere</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.</p> <p>1972-01-01</p> <p>Two types of magnetic field changes are repeatedly observed in the high latitude nightside magnetosphere in association with magnetic <span class="hlt">substorms</span>. One type is characterized by sudden decrease in the field strength, accompanied by an abrupt perturbation in the field declination angle. These changes are attributed to field aligned-sheet currents flowing on the high latitude boundary of an expanding plasma sheet following <span class="hlt">substorms</span>. Single sheets of field-aligned currents on this boundary tend to flow toward the earth in the morning quadrant and away in the evening. Multiple sheets of current may also occur, with the direction of the high latitude sheet generally being the same as for a single sheet. A second type of field change is a decrease in field inclination during <span class="hlt">substorms</span>. This is regarded as a manifestation of the changing field configuration during <span class="hlt">substorms</span> and can be described in terms of azimuthal currents.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930053284&hterms=earth+hour&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dearth%2Bhour','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930053284&hterms=earth+hour&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dearth%2Bhour"><span>The earth's magnetosphere under continued forcing - <span class="hlt">Substorm</span> activity during the passage of an interplanetary magnetic cloud</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Farrugia, C. J.; Freeman, M. P.; Burlaga, L. F.; Lepping, R. P.; Takahashi, K.</p> <p>1993-01-01</p> <p>Magnetic field and energetic particle observations from six spacecraft in the near-earth magnetotail are described and combined with ground magnetograms to document for the first time the magnetospheric <span class="hlt">substorm</span> activity during a 30-hour long transit of an interplanetary cloud at 1 AU. During an earlier 11-hr interval when B(z) was continuously positive, the magnetosphere was quiescent, while in a later 18-hr interval when B(z) was uninterruptedly negative a large magnetic storm was set off. In the latter interval the <span class="hlt">substorm</span> onsets recurred on average every 50 min. Their average recurrence frequency remained relatively undiminished even when the magnetic cloud B(z) and other measures of the interplanetary energy input decreased considerably. These results concur with current models of magnetospheric <span class="hlt">substorms</span> based on deterministic nonlinear dynamics. The <span class="hlt">substorm</span> onset occurred when the cloud's magnetic field had a persistent northward component but was predominantly westward pointing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26163518','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26163518"><span>Multiwavelength Resonance Raman Characterization of the Effect of <span class="hlt">Growth</span> <span class="hlt">Phase</span> and Culture Medium on Bacteria.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kunapareddy, Nagapratima; Grun, Jacob; Lunsford, Robert; Nikitin, Sergei; Wang, Zheng; Gillis, David</p> <p>2015-08-01</p> <p>We examine the use of multiwavelength ultraviolet (UV) resonance-Raman signatures to identify the effects of <span class="hlt">growth</span> <span class="hlt">phase</span> and <span class="hlt">growth</span> medium on gram-positive and gram-negative bacteria. Escherichia coli (E. coli), Citrobacter koseri (C. koseri), Citrobacter braakii (C. braakii), and Bacillus cereus (B. cereus) were grown to logarithmic and stationary <span class="hlt">phases</span> in nutrient broth and brain heart infusion broth. Resonance Raman spectra of bacteria were obtained at multiple wavelengths between 220 and 260 nm; a range that encompasses the resonance frequencies of cellular constituents. We find that spectra of the same bacterial species exhibit differences due to both <span class="hlt">growth</span> condition and <span class="hlt">growth</span> <span class="hlt">phase</span>, but the larger differences reflect changes due to <span class="hlt">growth</span> <span class="hlt">phase</span>. The differences in the Raman spectra correlate with genetic differences among the species. Using a Pearson correlation based algorithm, we achieve successful identification of these bacteria in 83% of the cases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMSM41A1841M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMSM41A1841M"><span>A Catapult (Slingshot) Current Sheet Relaxation Model for <span class="hlt">Substorm</span> Triggering</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Machida, S.; Miyashita, Y.; Ieda, A.</p> <p>2010-12-01</p> <p>Based on the results of our superposed epoch analysis of Geotail data, we have proposed a catapult (slingshot) current sheet relaxation model in which earthward flows are produced in the central plasma sheet (CPS) due to the catapult (slingshot) current sheet relaxation, together with the rapid enhancement of Poynting flux toward the CPS in the lobe around X ~ -15 Re about 4 min before the substrom onset. These earthward flows are characterized by plasma pressure decrease and large amplitude magnetic field fluctuations. When these flows reach X ~ 12Re in the magnetotail, they give significant disturbances to the inner magnetosphere to initiate some instability such as a ballooning instability or other instabilities, and the <span class="hlt">substorm</span> starts in the inner magnetosphere. The occurrence of the magnetic reconnection is a natural consequence of the initial convective earthward flows, because the relaxation of a highly stretched catapult current sheet produces a very thin current at its tailward edge being surrounded by intense magnetic fields which were formerly the off-equatorial lobe magnetic fields. Recently, Nishimura et al. [2010] reported that the <span class="hlt">substorm</span> onset begins when faint poleward discrete arcs collide with equatorward quiet arcs. The region of earthward convective flows correlatively moves earthward prior to the onset. Thus, this region of the earthward convective flows seems to correspond to the faint poleward discrete arcs. Interestingly, our statistical analysis shows that the earthward convective flows are not produced by the magnetic reconnection, but they are attributed to the dominance of the earthward JxB force over the tailward pressure associated with the progress of the plasma sheet thinning.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.2796H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.2796H"><span>Flow bursts, breakup arc, and <span class="hlt">substorm</span> current wedge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Haerendel, Gerhard</p> <p>2015-04-01</p> <p>Energy liberated by the reconnection process in the near-Earth tail is transported via flow bursts toward the dipolar magnetosphere during <span class="hlt">substorms</span>. The breakup arc is a manifestation of the arrival of the bursts under flow braking and energy deposition. Its structure and behavior is analyzed on the basis of five striking spatial, temporal, and energetic properties, qualitatively and in part also quantitatively. A key element is the formation of stop layers. They are thin layers, of the width of an ion gyro radius, in which the magnetic field makes a transition from tail to near-dipolar magnetosphere configurations and in which the kinetic energy of fast flows is converted into electromagnetic energy of kinetic Alfvén waves. The flows arise from the relaxation of the strong magnetic shear stresses in the leading part of the flow bursts. The bright narrow arcs of less than 10 km width inside the broad poleward expanding breakup arc, Alfvénic in nature and visually characterized by erratic short-lived rays, are seen as traces of the stop layers. The gaps between two narrow and highly structured arcs are filled with more diffuse emissions. They are attributed to the relaxation of the less strained magnetic field of the flow bursts. Eastward flows along the arcs are linked to the shrinking gaps between two successive arcs and the entry of auroral streamers into the dipolar magnetosphere in the midnight sector. Flow braking in the stop layers forms multiple pairs of narrow balanced currents and cannot be behind the formation of the <span class="hlt">substorm</span> current wedge. Instead, its origin is attributed to the force exerted by the dipolarized magnetic field of the flow bursts on the high-beta plasma, after the high magnetic shears have relaxed and the fast flows and stop layer process have subsided, in other words, to the "dying flow bursts."</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19760039141&hterms=field+dependence&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dfield%2Bdependence','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19760039141&hterms=field+dependence&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dfield%2Bdependence"><span>Dependence of the latitude of the cleft on the interplanetary magnetic field and <span class="hlt">substorm</span> activity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kamide, Y.; Burch, J. L.; Winningham, J. D.; Akasofu, S.-I.</p> <p>1976-01-01</p> <p>The latitudinal motion of the cleft (the polar cusp) associated with the southward interplanetary magnetic field (IMF) and <span class="hlt">substorm</span> activity is examined. The cleft location is identified on the basis of the location of midday auroras and of electron precipitation by the OGO 4 and ISIS 1 satellites. It is found that the IMF and <span class="hlt">substorm</span> activity control independently the latitude of the cleft and that they can shift the cleft location by 3 or 4 deg under average conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhPl...22e2705C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhPl...22e2705C"><span>A strategy for reducing stagnation <span class="hlt">phase</span> hydrodynamic instability <span class="hlt">growth</span> in inertial confinement fusion implosions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Clark, D. S.; Robey, H. F.; Smalyuk, V. A.</p> <p>2015-05-01</p> <p>Encouraging progress is being made in demonstrating control of ablation front hydrodynamic instability <span class="hlt">growth</span> in inertial confinement fusion implosion experiments on the National Ignition Facility [E. I. Moses, R. N. Boyd, B. A. Remington, C. J. Keane, and R. Al-Ayat, Phys. Plasmas 16, 041006 (2009)]. Even once ablation front stabilities are controlled, however, instability during the stagnation <span class="hlt">phase</span> of the implosion can still quench ignition. A scheme is proposed to reduce the <span class="hlt">growth</span> of stagnation <span class="hlt">phase</span> instabilities through the reverse of the "adiabat shaping" mechanism proposed to control ablation front <span class="hlt">growth</span>. Two-dimensional radiation hydrodynamics simulations confirm that improved stagnation <span class="hlt">phase</span> stability should be possible without compromising fuel compression.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017NuPhB.919...74M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017NuPhB.919...74M"><span>Bubble nucleation and <span class="hlt">growth</span> in very strong cosmological <span class="hlt">phase</span> transitions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mégevand, Ariel; Ramírez, Santiago</p> <p>2017-06-01</p> <p>Strongly first-order <span class="hlt">phase</span> transitions, i.e., those with a large order parameter, are characterized by a considerable supercooling and high velocities of <span class="hlt">phase</span> transition fronts. A very strong <span class="hlt">phase</span> transition may have important cosmological consequences due to the departures from equilibrium caused in the plasma. In general, there is a limit to the strength, since the metastability of the old <span class="hlt">phase</span> may prevent the transition to complete. Near this limit, the bubble nucleation rate achieves a maximum and thus departs from the widely assumed behavior in which it grows exponentially with time. We study the dynamics of this kind of <span class="hlt">phase</span> transitions. We show that in some cases a gaussian approximation for the nucleation rate is more suitable, and in such a case we solve analytically the evolution of the <span class="hlt">phase</span> transition. We compare the gaussian and exponential approximations with realistic cases and we determine their ranges of validity. We also discuss the implications for cosmic remnants such as gravitational waves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..122.5568H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..122.5568H"><span>Contribution of storm time <span class="hlt">substorms</span> to the prompt electric field disturbances in the equatorial ionosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hui, Debrup; Chakrabarty, D.; Sekar, R.; Reeves, G. D.; Yoshikawa, A.; Shiokawa, K.</p> <p>2017-05-01</p> <p>This study tries to bring out the fact that storm time <span class="hlt">substorms</span> can compete and at times significantly contribute to the geomagnetically disturbed time prompt penetration electric field effects on low and equatorial latitudes. Observations of unusual equatorial plasma drift data from Jicamarca Unattended Long-term Investigations of the Ionosphere and Atmosphere during two space weather events show that <span class="hlt">substorms</span> can induce both eastward and westward penetration electric fields under steady southward interplanetary magnetic field (IMF Bz) conditions. During the first event on 2 January 2005, the enhancement of the daytime eastward electric field over Jicamarca due to <span class="hlt">substorm</span> is found to be comparable with the Sq and interplanetary electric field (IEFy) generated electric fields combined. During the second event on 19 August 2006, the <span class="hlt">substorm</span> is seen to weaken the daytime eastward field thereby inducing a westward field in spite of the absence of northward turning of IMF Bz (overshielding). The westward electric field perturbation in the absence of any overshielding events is observationally sparse and contrary to the earlier results. Further, the <span class="hlt">substorm</span>-induced field is found to be strong enough to compete or almost nullify the effects of storm time IEFy fields. This study also shows quantitatively that at times <span class="hlt">substorm</span> contribution to the disturbed time prompt electric fields can be significant and thus should be taken into consideration in evaluating penetration events over low latitudes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900047779&hterms=disruption&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Ddisruption','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900047779&hterms=disruption&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Ddisruption"><span>A current disruption mechanism in the neutral sheet - A possible trigger for <span class="hlt">substorm</span> expansions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lui, A. T. Y.; Mankofsky, A.; Chang, C.-L.; Papadopoulos, K.; Wu, C. S.</p> <p>1990-01-01</p> <p>A linear analysis is performed to investigate the kinetic cross-field streaming instability in the earth's magnetotail neutral sheet region. Numerical solution of the dispersion equation shows that the instability can occur under conditions expected for the neutral sheet just prior to the onset of <span class="hlt">substorm</span> expansion. The excited waves are obliquely propagating whistlers with a mixed polarization in the lower hybrid frequency range. The ensuing turbulence of this instability can lead to a local reduction of the cross-tail current causing it to continue through the ionosphere to form a <span class="hlt">substorm</span> current wedge. A <span class="hlt">substorm</span> expansion onset scenario is proposed based on this instability in which the relative drift between ions and electrons is primarily due to unmagnetized ions undergoing current sheet acceleration in the presence of a cross-tail electric field. The required electric field strength is within the range of electric field values detected in the neutral sheet region during <span class="hlt">substorm</span> intervals. The skew in local time of <span class="hlt">substorm</span> onset location and the three conditions under which <span class="hlt">substorm</span> onset is observed can be understood on the basis of the proposed scenario.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900047779&hterms=triggers+alone&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dtriggers%2Balone','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900047779&hterms=triggers+alone&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dtriggers%2Balone"><span>A current disruption mechanism in the neutral sheet - A possible trigger for <span class="hlt">substorm</span> expansions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lui, A. T. Y.; Mankofsky, A.; Chang, C.-L.; Papadopoulos, K.; Wu, C. S.</p> <p>1990-01-01</p> <p>A linear analysis is performed to investigate the kinetic cross-field streaming instability in the earth's magnetotail neutral sheet region. Numerical solution of the dispersion equation shows that the instability can occur under conditions expected for the neutral sheet just prior to the onset of <span class="hlt">substorm</span> expansion. The excited waves are obliquely propagating whistlers with a mixed polarization in the lower hybrid frequency range. The ensuing turbulence of this instability can lead to a local reduction of the cross-tail current causing it to continue through the ionosphere to form a <span class="hlt">substorm</span> current wedge. A <span class="hlt">substorm</span> expansion onset scenario is proposed based on this instability in which the relative drift between ions and electrons is primarily due to unmagnetized ions undergoing current sheet acceleration in the presence of a cross-tail electric field. The required electric field strength is within the range of electric field values detected in the neutral sheet region during <span class="hlt">substorm</span> intervals. The skew in local time of <span class="hlt">substorm</span> onset location and the three conditions under which <span class="hlt">substorm</span> onset is observed can be understood on the basis of the proposed scenario.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010Ge%26Ae..50..314P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010Ge%26Ae..50..314P"><span>Effect of magnetospheric <span class="hlt">substorms</span> on asymptotic directions of arrival of cosmic ray relativistic protons</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pchelkin, V. V.</p> <p>2010-06-01</p> <p>The effect of magnetospheric storm on the propagation of relativistic protons has been analyzed. The method of trajectory calculations has been used to estimate changes in the reception cones for 21 stations, caused by the storm of July 19-20, 2000, accompanied by considerable saw-tooth <span class="hlt">substorm</span> disturbances. It has been indicated that the degree of the <span class="hlt">substorm</span> effect on the propagation of cosmic ray (CR) relativistic protons, registered with ground detectors, differs for different stations and depends on a distance of the particle trajectory from the localization of a <span class="hlt">substorm</span> disturbance. The maximal effect for the considered <span class="hlt">substorm</span> was found at Inuvik and McMurdo stations. Changes in the reception cone, caused by the <span class="hlt">substorm</span> at these stations, were comparable or even larger than changes caused by the storm. Based on the calculations, the conclusion has been drawn that a disturbance (<span class="hlt">substorm</span>) localized in space results in the appearance of relatively local zones on the Earth’s surface where characteristics of the asymptotic arrival of relativistic particles are changed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1175446','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1175446"><span>Condensed <span class="hlt">phase</span> conversion and <span class="hlt">growth</span> of nanorods instead of from vapor</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Geohegan, David B.; Seals, Roland D.; Puretzky, Alex A.; Fan, Xudong</p> <p>2005-08-02</p> <p>Compositions, systems and methods are described for condensed <span class="hlt">phase</span> conversion and <span class="hlt">growth</span> of nanorods and other materials. A method includes providing a condensed <span class="hlt">phase</span> matrix material; and activating the condensed <span class="hlt">phase</span> matrix material to produce a plurality of nanorods by condensed <span class="hlt">phase</span> conversion and <span class="hlt">growth</span> from the condensed chase matrix material instead of from vacor. The compositions are very strong. The compositions and methods provide advantages because they allow (1) formation rates of nanostructures necessary for reasonable production rates, and (2) the near net shaped production of component structures.</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('https://www.ncbi.nlm.nih.gov/pubmed/24406750','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24406750"><span>Morphology and <span class="hlt">growth</span> speed of hcp domains during shock-induced <span class="hlt">phase</span> transition in iron.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pang, Wei-Wei; Zhang, Ping; Zhang, Guang-Cai; Xu, Ai-Guo; Zhao, Xian-Geng</p> <p>2014-01-10</p> <p>Emergence and time evolution of micro-structured new-<span class="hlt">phase</span> domains play a crucial role in determining the macroscopic physical and mechanical behaviors of iron under shock compression. Here, we investigate, through molecular dynamics simulations and theoretical modelings, shock-induced <span class="hlt">phase</span> transition process of iron from body-centered-cubic (bcc) to hexagonal-close-packed (hcp) structure. We present a central-moment method and a rolling-ball algorithm to calculate and analyze the morphology and <span class="hlt">growth</span> speed of the hcp <span class="hlt">phase</span> domains, and then propose a <span class="hlt">phase</span> transition model to clarify our derived <span class="hlt">growth</span> law of the <span class="hlt">phase</span> domains. We also demonstrate that the new-<span class="hlt">phase</span> evolution process undergoes three distinguished stages with different time scales of the hcp <span class="hlt">phase</span> fraction in the system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JCrGr.455...99L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JCrGr.455...99L"><span>Compact seaweed <span class="hlt">growth</span> of peritectic <span class="hlt">phase</span> on confined, flat properitectic dendrites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ludwig, A.; Mogeritsch, J.</p> <p>2016-12-01</p> <p>Peritectic alloys form a variety of different solidification morphologies at low <span class="hlt">growth</span> rates. An alloy with a concentration that corresponds to the hyper-peritectic limit should show a cellular/dendritic solidification of the peritectic <span class="hlt">phase</span> for <span class="hlt">growth</span> velocities above the corresponding constitutional undercooling limit. However, due to nucleation retardation of the peritectic <span class="hlt">phase</span> we observed <span class="hlt">growth</span> of properitectic dendrites before cellular <span class="hlt">growth</span> of the peritectic could established. The transition happened via an overgrowth of dendrites with a thin layer of peritectic <span class="hlt">phase</span>. The observations were made using a transparent, metal-like solidifying peritectic system that was solidified directionally in thin samples. In the gap between the flat dendrites and the tubing walls, the peritectic <span class="hlt">phase</span> grew with a compact seaweed morphology, whereas in the interdendritic spacing it formed small-curved bumps. At same distance behind the tip region, more and more polycrystalline-like objects appeared at the elongated traces of the compact seaweed morphology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JPhA...50H5101A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JPhA...50H5101A"><span>Dynamics of the <span class="hlt">phase</span> transition boundary in the presence of nucleation and <span class="hlt">growth</span> of crystals</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Alexandrov, D. V.</p> <p>2017-08-01</p> <p>Nucleation and <span class="hlt">growth</span> of crystals in a moving metastable layer of <span class="hlt">phase</span> transition is analyzed theoretically. The integro-differential equations for the density distribution function and system metastability are solved analytically on the basis of a previously developed approach (Alexandrov and Malygin 2013 J. Phys. A: Math. Theor. 46 455101) in cases of the kinetic and diffusionally controlled regimes of crystal <span class="hlt">growth</span>. The Weber-Volmer-Frenkel-Zel’dovich and Meirs nucleation kinetics are considered. It is shown that the <span class="hlt">phase</span> transition boundary propagates with time as α\\sqrt{t}+\\varepsilon Z_1(t) , where Z_1(t)=β t7/2 and Z_1(t)=β t2 in cases of kinetic and diffusionally controlled <span class="hlt">growth</span> regimes. The <span class="hlt">growth</span> rate constants α and β as well as parameter ɛ are found analytically. The <span class="hlt">phase</span> transition boundary in the presence of particle nucleation and <span class="hlt">growth</span> moves slower than in cases without nucleation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017RJPCA..91.1635M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017RJPCA..91.1635M"><span>Mathematical model for the <span class="hlt">growth</span> of <span class="hlt">phases</span> in binary multiphase systems upon isothermic annealing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Molokhina, L. A.; Rogalin, V. E.; Filin, S. A.; Kaplunov, I. A.</p> <p>2017-09-01</p> <p>A phenomenological mathematical model of the formation and <span class="hlt">growth</span> of <span class="hlt">phases</span> in a binary multiphase system with allowance for factors influencing the process of diffusion in a binary system is presented. It is shown that <span class="hlt">phases</span> can grow for a certain time at different ratios between diffusion parameters according to a parabolic law that depends on the duration of isothermic annealing. They then slow their <span class="hlt">growth</span> after successor <span class="hlt">phases</span> appear at their interface with one component and can completely disappear from a diffusion layer or begin to grow again, but only at a rate slower than during their initial formation. The dependence of the thickness of each <span class="hlt">phase</span> layer in a multiphase diffusion zone on the duration of isothermic annealing and the ratio between the diffusion parameters in neighboring <span class="hlt">phases</span> is obtained. It is established that a certain ratio between the <span class="hlt">phase</span> <span class="hlt">growth</span> and rates of dissolution with allowance for the coefficients of diffusion in each <span class="hlt">phase</span> and the periods of incubation can result in the complete disappearance of one <span class="hlt">phase</span> as early as the onset of the <span class="hlt">growth</span> of <span class="hlt">phase</span> nuclei and be interpreted as a process of reaction diffusion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017NatMa..16..628H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017NatMa..16..628H"><span>Controlling the <span class="hlt">growth</span> of multiple ordered heteromolecular <span class="hlt">phases</span> by utilizing intermolecular repulsion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Henneke, Caroline; Felter, Janina; Schwarz, Daniel; Stefan Tautz, F.; Kumpf, Christian</p> <p>2017-06-01</p> <p>Metal/organic interfaces and their structural, electronic, spintronic and thermodynamic properties have been investigated intensively, aiming to improve and develop future electronic devices. In this context, heteromolecular <span class="hlt">phases</span> add new design opportunities simply by combining different molecules. However, controlling the desired <span class="hlt">phases</span> in such complex systems is a challenging task. Here, we report an effective way of steering the <span class="hlt">growth</span> of a bimolecular system composed of adsorbate species with opposite intermolecular interactions--repulsive and attractive, respectively. The repulsive species forms a two-dimensional lattice gas, the density of which controls which crystalline <span class="hlt">phases</span> are stable. Critical gas <span class="hlt">phase</span> densities determine the constant-area <span class="hlt">phase</span> diagram that describes our experimental observations, including eutectic regions with three coexisting <span class="hlt">phases</span>. We anticipate the general validity of this type of <span class="hlt">phase</span> diagram for binary systems containing two-dimensional gas <span class="hlt">phases</span>, and also show that the density of the gas <span class="hlt">phase</span> allows engineering of the interface structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23937554','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23937554"><span>Chirality-dependent vapor-<span class="hlt">phase</span> epitaxial <span class="hlt">growth</span> and termination of single-wall carbon nanotubes.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Bilu; Liu, Jia; Tu, Xiaomin; Zhang, Jialu; Zheng, Ming; Zhou, Chongwu</p> <p>2013-09-11</p> <p>Structurally uniform and chirality-pure single-wall carbon nanotubes are highly desired for both fundamental study and many of their technological applications, such as electronics, optoelectronics, and biomedical imaging. Considerable efforts have been invested in the synthesis of nanotubes with defined chiralities by tuning the <span class="hlt">growth</span> recipes but the approach has only limited success. Recently, we have shown that chirality-pure short nanotubes can be used as seeds for vapor-<span class="hlt">phase</span> epitaxial cloning <span class="hlt">growth</span>, opening up a new route toward chirality-controlled carbon nanotube synthesis. Nevertheless, the yield of vapor-<span class="hlt">phase</span> epitaxial <span class="hlt">growth</span> is rather limited at the present stage, due in large part to the lack of mechanistic understanding of the process. Here we report chirality-dependent <span class="hlt">growth</span> kinetics and termination mechanism for the vapor-<span class="hlt">phase</span> epitaxial <span class="hlt">growth</span> of seven single-chirality nanotubes of (9, 1), (6, 5), (8, 3), (7, 6), (10, 2), (6, 6), and (7, 7), covering near zigzag, medium chiral angle, and near armchair semiconductors, as well as armchair metallic nanotubes. Our results reveal that the <span class="hlt">growth</span> rates of nanotubes increase with their chiral angles while the active lifetimes of the <span class="hlt">growth</span> hold opposite trend. Consequently, the chirality distribution of a nanotube ensemble is jointly determined by both <span class="hlt">growth</span> rates and lifetimes. These results correlate nanotube structures and properties with their <span class="hlt">growth</span> behaviors and deepen our understanding of chirality-controlled <span class="hlt">growth</span> of nanotubes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017BGeo...14.1493S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017BGeo...14.1493S"><span>Physiology regulates the relationship between coccosphere geometry and <span class="hlt">growth</span> <span class="hlt">phase</span> in coccolithophores</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sheward, Rosie M.; Poulton, Alex J.; Gibbs, Samantha J.; Daniels, Chris J.; Bown, Paul R.</p> <p>2017-03-01</p> <p>Coccolithophores are an abundant phytoplankton group that exhibit remarkable diversity in their biology, ecology and calcitic exoskeletons (coccospheres). Their extensive fossil record is a testament to their important biogeochemical role and is a valuable archive of biotic responses to environmental change stretching back over 200 million years. However, to realise the full potential of this archive for (palaeo-)biology and biogeochemistry requires an understanding of the physiological processes that underpin coccosphere architecture. Using culturing experiments on four modern coccolithophore species (Calcidiscus leptoporus, Calcidiscus quadriperforatus, Helicosphaera carteri and Coccolithus braarudii) from three long-lived families, we investigate how coccosphere architecture responds to shifts from exponential (rapid cell division) to stationary (slowed cell division) <span class="hlt">growth</span> <span class="hlt">phases</span> as cell physiology reacts to nutrient depletion. These experiments reveal statistical differences in coccosphere size and the number of coccoliths per cell between these two <span class="hlt">growth</span> <span class="hlt">phases</span>, specifically that cells in exponential-<span class="hlt">phase</span> <span class="hlt">growth</span> are typically smaller with fewer coccoliths, whereas cells experiencing <span class="hlt">growth</span>-limiting nutrient depletion have larger coccosphere sizes and greater numbers of coccoliths per cell. Although the exact numbers are species-specific, these <span class="hlt">growth-phase</span> shifts in coccosphere geometry demonstrate that the core physiological responses of cells to nutrient depletion result in increased coccosphere sizes and coccoliths per cell across four different coccolithophore families (Calcidiscaceae, Coccolithaceae, Isochrysidaceae and Helicosphaeraceae), a representative diversity of this phytoplankton group. Building on this, the direct comparison of coccosphere geometries in modern and fossil coccolithophores enables a proxy for <span class="hlt">growth</span> <span class="hlt">phase</span> to be developed that can be used to investigate <span class="hlt">growth</span> responses to environmental change throughout their long evolutionary</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SunGe..11..125G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SunGe..11..125G"><span><span class="hlt">Substorms</span> observations during two geomagnetically active periods in March 2012 and March 2015</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guineva, V.; Despirak, I.; Kozelov, B.</p> <p>2016-05-01</p> <p>In this work two events of strong geomagnetic activity were examined: the period 7-17 March 2012, which is one of the most disturbed periods during the ascending <span class="hlt">phase</span> of Solar Cycle 24, and the severe geomagnetic storm on 17-20 March 2015. During the first period four consecutive magnetic storms occurred on 7, 9, 12, and 15 March. These storms were caused by Sheath, MC and HSS, and the detailed scenarios for the storms were different. The second event is a storm of fourth level with Kp = 8, the strongest one during the last four years, the so-called "St. Patrick's Day 2015 Event". A geomagnetic storm of such intensity was observed in September 2011. Our analysis was based on the 10-s sampled IMAGE magnetometers data, the 1-min sampled OMNI solar wind and interplanetary magnetic field (IMF) data and observations of the Multiscale Aurora Imaging Network (MAIN) in Apatity. The particularities in the behaviours of <span class="hlt">substorms</span> connected with different storms during these two interesting strongly disturbed periods are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSM41B2431K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSM41B2431K"><span>Modeling particle injections during magnetospheric <span class="hlt">substorm</span> by a propagating earthward electromagnetic pulse.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kalugin, G. A.; Kabin, K.; Donovan, E.; Spanswick, E.</p> <p>2016-12-01</p> <p>During <span class="hlt">substorm</span> expansion <span class="hlt">phase</span> the electrons and ions with energies of up to 100 keV appear in the near-Earth magnetotail. Often, this increase occurs simultaneously for a broad range of particle energies; such events are called dispersionless injections (DIs). Explanations of DIs usually relay on some form of an earthward propagating electromagnetic pulse, which is capable of effectively energizing an initial distribution of electrons and ions. Most of the previous models of such pulses were developed for the equatorial plane only. We propose a new model of an electromagnetic pulse which is two-dimensional in the meridional plane. Electric and magnetic fields in the pulse are calculated self-consistently and satisfy Maxwell's equations. We use realistic time-independent stretched magnetic field as the background. Our model has several adjustable parameters, such as the speed of the pulse propagation, its amplitude and spatial extent, which makes it versatile enough to investigate effects of the pulse characteristics on the particle energization. We present and discuss several examples of particle energization in our model and find that in some cases the energies of the seed electrons can increase by a factor of 10 or more. Two-dimensional nature of our model allows us to visualize the motion of the field lines in the meridional plane associated with the travelling electromagnetic pulse and to calculate the ionospheric footprints of the particle dynamics in the equatorial plane.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080044893','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080044893"><span>Orbit Determination and Navigation of the Time History of Events and Macroscale Interactions during <span class="hlt">Substorms</span> (THEMIS)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Morinelli, Patrick; Cosgrove, jennifer; Blizzard, Mike; Nicholson, Ann; Robertson, Mika</p> <p>2007-01-01</p> <p>This paper provides an overview of the launch and early orbit activities performed by the NASA Goddard Space Flight Center's (GSFC) Flight Dynamics Facility (FDF) in support of five probes comprising the Time History of Events and Macroscale Interactions during <span class="hlt">Substorms</span> (THEMIS) spacecraft. The FDF was tasked to support THEMIS in a limited capacity providing backup orbit determination support for validation purposes for all five THEMIS probes during launch plus 30 days in coordination with University of California Berkeley Flight Dynamics Center (UCB/FDC). The FDF's orbit determination responsibilities were originally planned to be as a backup to the UCB/FDC for validation purposes only. However, various challenges early on in the mission and a Spacecraft Emergency declared thirty hours after launch placed the FDF team in the role of providing the orbit solutions that enabled contact with each of the probes and the eventual termination of the Spacecraft Emergency. This paper details the challenges and various techniques used by the GSFC FDF team to successfully perform orbit determination for all five THEMIS probes during the early mission. In addition, actual THEMIS orbit determination results are presented spanning the launch and early orbit mission <span class="hlt">phase</span>. Lastly, this paper enumerates lessons learned from the THEMIS mission, as well as demonstrates the broad range of resources and capabilities within the FDF for supporting critical launch and early orbit navigation activities, especially challenging for constellation missions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080012701','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080012701"><span>Orbit Determination and Navigation of the Time History of Events and Macroscale Interactions during <span class="hlt">Substorms</span> (THEMIS)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Morinelli, Patrick; Cosgrove, Jennifer; Blizzard, Mike; Robertson, Mike</p> <p>2007-01-01</p> <p>This paper provides an overview of the launch and early orbit activities performed by the NASA Goddard Space Flight Center's (GSFC) Flight Dynamics Facility (FDF) in support of five probes comprising the Time History of Events and Macroscale Interactions during <span class="hlt">Substorms</span> (THEMIS) spacecraft. The FDF was tasked to support THEMIS in a limited capacity providing backup orbit determination support for validation purposes for all five THEMIS probes during launch plus 30 days in coordination with University of California Berkeley Flight Dynamics Center (UCB/FDC)2. The FDF's orbit determination responsibilities were originally planned to be as a backup to the UCB/FDC for validation purposes only. However, various challenges early on in the mission and a Spacecraft Emergency declared thirty hours after launch placed the FDF team in the role of providing the orbit solutions that enabled contact with each of the probes and the eventual termination of the Spacecraft Emergency. This paper details the challenges and various techniques used by the GSFC FDF team to successfully perform orbit determination for all five THEMIS probes during the early mission. In addition, actual THEMIS orbit determination results are presented spanning the launch and early orbit mission <span class="hlt">phase</span>. Lastly, this paper enumerates lessons learned from the THEMIS mission, as well as demonstrates the broad range of resources and capabilities within the FDF for supporting critical launch and early orbit navigation activities, especially challenging for constellation missions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27405605','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27405605"><span>Effects of salt stress imposed during two <span class="hlt">growth</span> <span class="hlt">phases</span> on cauliflower production and quality.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Giuffrida, Francesco; Cassaniti, Carla; Malvuccio, Angelo; Leonardi, Cherubino</p> <p>2017-03-01</p> <p>Cultivation of cauliflower is diffused in Mediterranean areas where water salinity results in the need to identify alternative irrigation sources or management strategies. Using saline water during two <span class="hlt">growth</span> <span class="hlt">phases</span> (from transplanting to visible appearance of inflorescence or from appearance of inflorescence to head harvest), the present study aimed to identify the <span class="hlt">growth</span> period that is more suitable for irrigation with low quality water in relation to cauliflower production and quality. Salinity affected cauliflower <span class="hlt">growth</span> mainly when imposed in the first <span class="hlt">growth</span> <span class="hlt">phase</span>. The <span class="hlt">growth</span> reduction depended mainly on ion-specific effects, although slight nutrient imbalances as a result of Na(+) and Cl(-) antagonisms were observed. The use of non-saline water in the first or second <span class="hlt">growth</span> period reduced both the osmotic and toxic effects of salinity. When salinity was applied during inflorescence <span class="hlt">growth</span>, yield was reduced because of a restriction of water accumulation in the head. The results of the present study demonstrate the possibility of producing marketable cauliflower heads under conditions of salinity by timing the application of the best quality water during the first <span class="hlt">growth</span> <span class="hlt">phase</span> to improve fruit quality and during the second <span class="hlt">phase</span> to reduce the negative effects of salinity on yield. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1133990','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1133990"><span>A <span class="hlt">phase</span>-field model coupled with lattice kinetics solver for modeling crystal <span class="hlt">growth</span> in furnaces</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lin, Guang; Bao, Jie; Xu, Zhijie; Tartakovsky, Alexandre M.; Henager, Charles H.</p> <p>2014-02-02</p> <p>In this study, we present a new numerical model for crystal <span class="hlt">growth</span> in a vertical solidification system. This model takes into account the buoyancy induced convective flow and its effect on the crystal <span class="hlt">growth</span> process. The evolution of the crystal <span class="hlt">growth</span> interface is simulated using the <span class="hlt">phase</span>-field method. Two novel <span class="hlt">phase</span>-field models are developed to model the crystal <span class="hlt">growth</span> interface in vertical gradient furnaces with two temperature profile setups: 1) fixed wall temperature profile setup and 2) time-dependent temperature profile setup. A semi-implicit lattice kinetics solver based on the Boltzmann equation is employed to model the unsteady incompressible flow. This model is used to investigate the effect of furnace operational conditions on crystal <span class="hlt">growth</span> interface profiles and <span class="hlt">growth</span> velocities. For a simple case of macroscopic radial <span class="hlt">growth</span>, the <span class="hlt">phase</span>-field model is validated against an analytical solution. Crystal <span class="hlt">growth</span> in vertical gradient furnaces with two temperature profile setups have been also investigated using the developed model. The numerical simulations reveal that for a certain set of temperature boundary conditions, the heat transport in the melt near the <span class="hlt">phase</span> interface is diffusion dominant and advection is suppressed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25048532','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25048532"><span>A magnetosome-associated cytochrome MamP is critical for magnetite crystal <span class="hlt">growth</span> during the exponential <span class="hlt">growth</span> <span class="hlt">phase</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Taoka, Azuma; Eguchi, Yukako; Mise, Shingo; Oestreicher, Zachery; Uno, Fumio; Fukumori, Yoshihiro</p> <p>2014-09-01</p> <p>Magnetotactic bacteria use a specific set of conserved proteins to biomineralize crystals of magnetite or greigite within their cells in organelles called magnetosomes. Using Magnetospirillum magneticum AMB-1, we examined one of the magnetotactic bacteria-specific conserved proteins named MamP that was recently reported as a new type of cytochrome c that has iron oxidase activity. We found that MamP is a membrane-bound cytochrome, and the MamP content increases during the exponential <span class="hlt">growth</span> <span class="hlt">phase</span> compared to two other magnetosome-associated proteins on the same operon, MamA and MamK. To assess the function of MamP, we overproduced MamP from plasmids in wild-type (WT) AMB-1 and found that during the exponential <span class="hlt">phase</span> of <span class="hlt">growth</span>, these cells contained more magnetite crystals that were the same size as crystals in WT cells. Conversely, when the heme c-binding motifs within the mamP on the plasmid was mutated, the cells produced the same number of crystals, but smaller crystals than in WT cells during exponential <span class="hlt">growth</span>. These results strongly suggest that during the exponential <span class="hlt">phase</span> of <span class="hlt">growth</span>, MamP is crucial to the normal <span class="hlt">growth</span> of magnetite crystals during biomineralization. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PhLB..772..517X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PhLB..772..517X"><span>Entanglement <span class="hlt">growth</span> during Van der Waals like <span class="hlt">phase</span> transition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, Hao</p> <p>2017-09-01</p> <p>We address the problem of describing the coexistence state of two different black holes and Van der Waals like <span class="hlt">phase</span> transition in Reissner-Nordström-AdS space-time. We start by a small charged black hole, then introduce a collapsing neutral thin-shell described by Vaidya metric to form a large one. The formation of the large black hole does not change the temperature and free energy of the initial state. We discuss the entanglement growing during the <span class="hlt">phase</span> transition. The transition is always continuous and the saturation time is determined by the final state. It opens a possibility for studying the holography from excited states to excited states.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006PhDT.......114K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006PhDT.......114K"><span>Thin film <span class="hlt">growth</span> and <span class="hlt">phase</span> competition of layered ferroelectrics and related perovskite <span class="hlt">phases</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kavaipatti, Balasubramaniam R.</p> <p></p> <p>"Geometric ferroelectrics" form an interesting, albeit not well-studied, subset of ferroelectric materials. The term "geometric ferroelectrics" is used for compounds that exhibit ferroelectricity owing to a simple relaxation of frustrations in the unit cell geometry, and not as a result of either a second-order Jahn-Teller distortion (SOJT) or a cooperative lone pair displacive mechanism. The structure-property relationships in such materials has not been investigated in depth owing to the limited number of known materials that adopt the "geometric ferroelectric" structures. This thesis is concerned with the development of a synthesis method that will allow one to realize materials in these structures over wider composition spaces. Thin film synthesis of two classes of oxide geometric ferroelectric materials---ABO 3 compounds adopting the layered hexagonal LuMnO3 structure (h-REMnO3) and A4B4O 14 (Sr2Nb2O7) compounds adopting the [110]-layered perovskite structure, which both compete in stability with the close-packed perovskite (p-REMnO3 or SrNbO3) structure---is the focus of this thesis. Materials in both the classes were grown by Pulsed Laser Deposition (PLD) on various substrates and under various process conditions (temperature, energy, process gas type/pressure...) and characterized mainly by X-ray diffraction. The temperature, pressure, and nature of the ambient gas are the primary influence on the <span class="hlt">phase</span> (and orientation) selected during the thin film <span class="hlt">growth</span> of materials in the SrNbOy family. In N2 ambients, when the partial pressure of O2 is very low, reduction of the Nb cation to the 4+ state resulted in the perovskite SrNbO3 formation on SrTiO3(100) and (110), as well as MgO(100) and (111). On SrTiO 3, cube-on-cube epitaxy was observed, while on MgO, polycrystalline films were obtained. On the other hand, O2 ambients favored the Nb cation in its fully oxidized pentavalent state, resulting in formation of (110)-layered perovskite Sr2Nb2O7. On SrTiO3</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24340946','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24340946"><span>[The two-<span class="hlt">phase</span> <span class="hlt">growth</span> medium for sub-culturing of Helicobacter pylori].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Isaeva, G Sh; Aleshkin, V A; Sel'kova, E P; Gerasimova, M S; Moroz, P I</p> <p>2013-06-01</p> <p>A. Pylori is a very undemanding microorganism needing the in support of complex of conditions including particular atmosphere, temperature of culturing and composition of <span class="hlt">growth</span> medium. The two-<span class="hlt">phase</span> <span class="hlt">growth</span> medium is recommended to sub-culturing in Petri dishes with diameter of 90 mm. The <span class="hlt">growth</span> medium consists of chocolate agar with addition of Schedler broth and enriched with 10% serum of cattle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014MSMSE..22a5003A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014MSMSE..22a5003A"><span>Nucleation kinetics and crystal <span class="hlt">growth</span> with fluctuating rates at the intermediate stage of <span class="hlt">phase</span> transitions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Alexandrov, D. V.; Malygin, A. P.</p> <p>2014-01-01</p> <p>Crystal <span class="hlt">growth</span> kinetics accompanied by particle <span class="hlt">growth</span> with fluctuating rates at the intermediate stage of <span class="hlt">phase</span> transitions is analyzed theoretically. The integro-differential model of governing equations is solved analytically for size-independent <span class="hlt">growth</span> rates and arbitrary dependences of the nucleation frequency on supercooling/supersaturation. Two important cases of Weber-Volmer-Frenkel-Zel'dovich and Mier nucleation kinetics are detailed. A Fokker-Plank type equation for the crystal-size density distribution function is solved explicitly.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=262417','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=262417"><span>Tyrosine requirement during the rapid catch-up <span class="hlt">growth</span> <span class="hlt">phase</span> of recovery from severe childhood undernutrition</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>The requirement for aromatic amino acids, during the rapid catch-up in weight <span class="hlt">phase</span> of recovery from severe childhood under nutrition (SCU) is not clearly established. As a first step, the present study aimed to estimate the tyrosine requirement of children with SCU during the catch-up <span class="hlt">growth</span> <span class="hlt">phase</span> ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19720036572&hterms=log&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dlog','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19720036572&hterms=log&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dlog"><span>Ultrastructure of Pseudomonas saccharophila at early and late log <span class="hlt">phase</span> of <span class="hlt">growth</span>.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Young, H. L.; Chao, F.-C.; Turnbill, C.; Philpott, D. E.</p> <p>1972-01-01</p> <p>Description of the fine structure of Pseudomonas saccarophila at the early log <span class="hlt">phase</span> and the late log <span class="hlt">phase</span> of <span class="hlt">growth</span>, such as shown by electron microscopy with the aid of various techniques of preparation. The observations reported suggested that, under the experimental conditions applied, P. saccharophila multiplies by the method of constrictive division.</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('https://www.osti.gov/scitech/biblio/22489797','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22489797"><span><span class="hlt">Growth</span> and characterization of α and β-<span class="hlt">phase</span> tungsten films on various substrates</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lee, Jeong-Seop; Cho, Jaehun; You, Chun-Yeol</p> <p>2016-03-15</p> <p>The <span class="hlt">growth</span> conditions of tungsten thin films were investigated using various substrates including Si, Si/SiO{sub 2}, GaAs, MgO, and Al{sub 2}O{sub 3}, and recipes were discovered for the optimal <span class="hlt">growth</span> conditions of thick metastable β-<span class="hlt">phase</span> tungsten films on Si, GaAs, and Al{sub 2}O{sub 3} substrates, which is an important material in spin orbit torque studies. For the Si/SiO{sub 2} substrate, the crystal <span class="hlt">phase</span> of the tungsten films was different depending upon the tungsten film thickness, and the transport properties were found to dramatically change with the thickness owing to a change in <span class="hlt">phase</span> from the α + β <span class="hlt">phase</span> to the α-<span class="hlt">phase</span>. It is shown that the crystal <span class="hlt">phase</span> changes are associated with residual stress in the tungsten films and that the resistivity is closely related to the grain sizes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22415250','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22415250"><span>Selective <span class="hlt">growth</span> of single <span class="hlt">phase</span> VO{sub 2}(A, B, and M) polymorph thin films</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Srivastava, Amar; Saha, Surajit; Rotella, Helene; Pal, Banabir; Kalon, Gopinadhan; Mathew, Sinu; Motapothula, Mallikarjuna; Dykas, Michal; Yang, Ping; Okunishi, Eiji; Sarma, D. D.; Venkatesan, T.</p> <p>2015-02-01</p> <p>We demonstrate the <span class="hlt">growth</span> of high quality single <span class="hlt">phase</span> films of VO{sub 2}(A, B, and M) on SrTiO{sub 3} substrate by controlling the vanadium arrival rate (laser frequency) and oxidation of the V atoms. A <span class="hlt">phase</span> diagram has been developed (oxygen pressure versus laser frequency) for various <span class="hlt">phases</span> of VO{sub 2} and their electronic properties are investigated. VO{sub 2}(A) <span class="hlt">phase</span> is insulating VO{sub 2}(B) <span class="hlt">phase</span> is semi-metallic, and VO{sub 2}(M) <span class="hlt">phase</span> exhibits a metal-insulator transition, corroborated by photo-electron spectroscopic studies. The ability to control the <span class="hlt">growth</span> of various polymorphs opens up the possibility for novel (hetero)structures promising new device functionalities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=179378','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=179378"><span>Role of mga in <span class="hlt">growth</span> <span class="hlt">phase</span> regulation of virulence genes of the group A streptococcus.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>McIver, K S; Scott, J R</p> <p>1997-01-01</p> <p>To determine whether <span class="hlt">growth</span> <span class="hlt">phase</span> affects the expression of mga and other virulence-associated genes in the group A streptococcus (GAS), total RNA was isolated from the serotype M6 GAS strain JRS4 at different <span class="hlt">phases</span> of <span class="hlt">growth</span> and transcript levels were quantitated by hybridization with radiolabeled DNA probes. Expression of mga (which encodes a multiple gene regulator) and the Mga-regulated genes emm (which encodes M protein) and scpA (which encodes a complement C5a peptidase) was found to be maximal in exponential <span class="hlt">phase</span> and shut off as the bacteria entered stationary <span class="hlt">phase</span>, while the housekeeping genes recA and rpsL showed constant transcript levels over the same period of <span class="hlt">growth</span>. Expression of mga from a foreign phage promoter in a mga-deleted GAS strain (JRS519) altered the wild-type <span class="hlt">growth</span> <span class="hlt">phase</span>-dependent transcription profile seen for emm and scpA, as well as for mga. Therefore, the temporal control of mga expression requires its upstream promoter region, and the subsequent <span class="hlt">growth</span> <span class="hlt">phase</span> regulation of emm and scpA is Mga dependent. A number of putative virulence genes in JRS4 were shown not to require Mga for their expression, although several exhibited <span class="hlt">growth</span> <span class="hlt">phase</span>-dependent regulation that was similar to mga, i.e., slo (which encodes streptolysin O) and plr (encoding the plasmin receptor/glyceraldehyde-3-phosphate dehydrogenase). Still others showed a markedly different pattern of expression (the genes for the superantigen toxins MF and SpeC). These results suggest the existence of complex levels of global regulation sensitive to <span class="hlt">growth</span> <span class="hlt">phase</span> that directly control the expression of virulence genes and mga in GAS. PMID:9260962</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRA..119.9714S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRA..119.9714S"><span>Event study combining magnetospheric and ionospheric perspectives of the <span class="hlt">substorm</span> current wedge modeling</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.; Nikolaev, A. V.; Kubyshkina, M. V.; Tsyganenko, N. A.; Singer, H. J.; Rodriguez, J. V.; Angelopoulos, V.; Nakamura, R.; Milan, S. E.; Coxon, J. C.; Anderson, B. J.; Korth, H.</p> <p>2014-12-01</p> <p>Unprecedented spacecraft and instrumental coverage and the isolated nature and distinct step-like development of a <span class="hlt">substorm</span> on 17 March 2010 has allowed validation of the two-loop <span class="hlt">substorm</span> current wedge model (SCW2L). We find a close spatiotemporal relationship of the SCW with many other essential signatures of <span class="hlt">substorm</span> activity in the magnetotail and demonstrate its azimuthally localized structure and stepwise expansion in the magnetotail. We confirm that ground SCW diagnostics makes it possible to reconstruct and organize the azimuthal spatiotemporal <span class="hlt">substorm</span> development pattern with accuracy better than 1 h magnetic local time (MLT) in the case of medium-scale <span class="hlt">substorm</span>. The Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE)-based study of global field-aligned current distribution indicates that (a) the SCW-related field-aligned current system consists of simultaneously activated R1- and R2-type currents, (b) their net currents have a R1-sense, and (c) locations of net current peaks are consistent with the SCW edge locations inferred from midlatitude variations. Thanks to good azimuthal coverage of four GOES and three Time History of Events and Macroscale Interactions during <span class="hlt">Substorms</span> spacecraft, we evaluated the intensities of the SCW R1- and R2-like current loops (using the SCW2L model) obtained from combined magnetospheric and ground midlatitude magnetic observations and found the net currents consistent (within a factor of 2) with the AMPERE-based estimate. We also ran an adaptive magnetospheric model and show that SCW2L model outperforms it in predicting the magnetic configuration changes during <span class="hlt">substorm</span> dipolarizations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JGRA..116.9214N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JGRA..116.9214N"><span>Relations between multiple auroral streamers, pre-onset thin arc formation, and <span class="hlt">substorm</span> auroral onset</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nishimura, Y.; Lyons, L. R.; Angelopoulos, V.; Kikuchi, T.; Zou, S.; Mende, S. B.</p> <p>2011-09-01</p> <p>Recent ground-based imager observations have provided evidence of precursor auroral activity leading to <span class="hlt">substorm</span> auroral onset, where the precursor is initiated by a poleward boundary intensification (PBI) followed by an auroral streamer moving equatorward toward the onset latitude leading to <span class="hlt">substorm</span> auroral onset. However, since many streamers do not lead to <span class="hlt">substorms</span>, the question arises as to what conditions are required for streamers to lead to onset. Using 382 events detected by the THEMIS all-sky imagers during 2007-2009, we examined the properties of latitudinally thin, quiet arcs that eventually break up during the <span class="hlt">substorm</span> auroral onset and the relationship of such quiet arcs to streamers. We found that a pre-existing latitudinally thin quiet arc that leads to auroral onset is much brighter than prior thin arcs that do not lead to onset, and that streamers that do not lead to onset form or intensify such quiet arcs. The newly formed or intensified quiet arc remains bright for a few to tens of minutes (˜20 min on average) until a subsequent streamer leads to <span class="hlt">substorm</span> auroral onset along the pre-existing arc. The pre-onset sequence proposed here suggests that both types of streamers, which do and do not lead to <span class="hlt">substorms</span>, enhance auroral luminosity near the equatorward boundary of the oval, and that a sufficiently intense, quiet time thin arc near the poleward edge of proton precipitation, likely corresponding to a large plasma pressure gradient in the near-Earth plasma sheet, reflects important pre-conditions for a precursor flow burst to trigger <span class="hlt">substorm</span> auroral onset.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1344215','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1344215"><span>A Kinetic Model for GaAs <span class="hlt">Growth</span> by Hydride Vapor <span class="hlt">Phase</span> Epitaxy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Schulte, Kevin L.; Simon, John; Jain, Nikhil; Young, David L.; Ptak, Aaron J.</p> <p>2016-11-21</p> <p>Precise control of the <span class="hlt">growth</span> of III-V materials by hydride vapor <span class="hlt">phase</span> epitaxy (HVPE) is complicated by the fact that the <span class="hlt">growth</span> rate depends on the concentrations of nearly all inputs to the reactor and also the reaction temperature. This behavior is in contrast to metalorganic vapor <span class="hlt">phase</span> epitaxy (MOVPE), which in common practice operates in a mass transport limited regime where <span class="hlt">growth</span> rate and alloy composition are controlled almost exclusively by flow of the Group III precursor. In HVPE, the <span class="hlt">growth</span> rate and alloy compositions are very sensitive to temperature and reactant concentrations, which are strong functions of the reactor geometry. HVPE <span class="hlt">growth</span>, particularly the <span class="hlt">growth</span> of large area materials and devices, will benefit from the development of a <span class="hlt">growth</span> model that can eventually be coupled with a computational fluid dynamics (CFD) model of a specific reactor geometry. In this work, we develop a <span class="hlt">growth</span> rate law using a Langmuir-Hinshelwood (L-H) analysis, fitting unknown parameters to <span class="hlt">growth</span> rate data from the literature that captures the relevant kinetic and thermodynamic phenomena of the HVPE process. We compare the L-H rate law to <span class="hlt">growth</span> rate data from our custom HVPE reactor, and develop quantitative insight into reactor performance, demonstrating the utility of the <span class="hlt">growth</span> model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA189725','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA189725"><span>Fundamental Studies on High Temperature Deformation Recrystallization, and Grain <span class="hlt">Growth</span> of Two-<span class="hlt">Phase</span> Materials.</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1988-01-01</p> <p>some of the alpha-beta Titanium alloys where the beta <span class="hlt">phase</span> is harder but its diffusivities are higher than that of the alpha <span class="hlt">phase</span>. To further...shrinking particle and diffusion of soluteoccurs to the particle under steady state conditions (9). V In the two <span class="hlt">phase</span> alloys, such as a-P titanium ... diffusivity of the alloying elements on the particle <span class="hlt">growth</span> kinetics of a - 0 titanium alloys. It is hoped that such an understanding will be</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JaJAP..56c8002I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JaJAP..56c8002I"><span>Improved thermodynamic analysis of gas reactions for compound semiconductor <span class="hlt">growth</span> by vapor-<span class="hlt">phase</span> epitaxy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Inatomi, Yuya; Kangawa, Yoshihiro; Kakimoto, Koichi; Koukitu, Akinori</p> <p>2017-03-01</p> <p>An improved thermodynamic analysis method for vapor-<span class="hlt">phase</span> epitaxy is proposed. In the conventional method, the mass-balance constraint equations are expressed in terms of variations in partial pressure. Although the conventional method is appropriate for gas–solid reactions occurring near the <span class="hlt">growth</span> surface, it is not suitable for gas reactions that involve changes in the number of gas molecules. We reconsider the constraint equations in order to predict the effect of gas reactions on semiconductor <span class="hlt">growth</span> processes. To demonstrate the feasibility of the improved method, the <span class="hlt">growth</span> process of group-III nitrides by metalorganic vapor-<span class="hlt">phase</span> epitaxy has been investigated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JNuM..414..114S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JNuM..414..114S"><span>A <span class="hlt">phase</span>-field simulation of uranium dendrite <span class="hlt">growth</span> on the cathode in the electrorefining process</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shibuta, Yasushi; Unoura, Seiji; Sato, Takumi; Shibata, Hiroki; Kurata, Masaki; Suzuki, Toshio</p> <p>2011-07-01</p> <p>The uranium dendrite <span class="hlt">growth</span> on the cathode during the pyroprocessing of uranium is investigated using a novel <span class="hlt">phase</span>-field model, in which electrodeposition of uranium and zirconium from the molten-salt is taken into account. The threshold concentration of zirconium in the molten salt demarcating the dendritic and planar <span class="hlt">growth</span> is then estimated as a function of the current density. Moreover, the <span class="hlt">growth</span> process of both the dendritic and planar electrodeposits has been demonstrated by way of varying the mobility of the <span class="hlt">phase</span> field, which consists of the effect of attachment kinetics and diffusion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM51E2597M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM51E2597M"><span>Development of the Near-Earth Magnetotail and the Auroral Arc Associated with <span class="hlt">Substorm</span> Onset: Evidence for a New Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miyashita, Y.; Hiraki, Y.; Angelopoulos, V.; Ieda, A.; Machida, S.</p> <p>2015-12-01</p> <p>We have studied the time sequence of the development of the near-Earth magnetotail and the auroral arc associated with a <span class="hlt">substorm</span> onset, using the data from the THEMIS spacecraft and ground-based observatories at high temporal and spatial resolutions. We discuss four steps of the auroral development, linking them to magnetotail changes: the auroral fading, the initial brightening of an auroral onset arc, the enhancement of the wave-like structure, and the poleward expansion. A case study shows that near-Earth magnetic reconnection began at X~-17 RE at least ~3 min before the auroral initial brightening and ~1 min before the auroral fading. Ionospheric large-scale convection also became enhanced just before the auroral fading and before the auroral initial brightening. Then low-frequency waves were amplified in the plasma sheet at X~-10 RE, with the pressure increase due to the arrival of the earthward flow from the near-Earth reconnection site ~20 s before the enhancement of the auroral wave-like structure. Finally, the dipolarization began ~30 s before the auroral poleward expansion. On the basis of the present observations, we suggest that near-Earth magnetic reconnection plays two roles in the <span class="hlt">substorm</span> triggering. First, it generates a fast earthward flow and Alfvén waves. When the Alfvén waves which propagate much faster than the fast flow reach the ionosphere, large-scale ionospheric convection is enhanced, leading to the auroral initial brightening and subsequent gradual <span class="hlt">growth</span> of the auroral wave-like structure. Second, when the reconnection-initiated fast flow reaches the near-Earth magnetotail, it promotes rapid <span class="hlt">growth</span> of an instability, such as the ballooning instability, and the auroral wave-like structure is further enhanced. When the instability grows sufficiently, the dipolarization and the auroral poleward expansion are initiated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/933126','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/933126"><span>Role of Nucleation and <span class="hlt">Growth</span> in Two-<span class="hlt">Phase</span> Microstructure Formation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shin, Jong Ho</p> <p>2007-01-01</p> <p>During the directional solidification of peritectic alloys, a rich variety of two-<span class="hlt">phase</span> microstructures develop, and the selection process of a specific microstructure is complicated due to the following two considerations. (1) In contrast to many single <span class="hlt">phase</span> and eutectic microstructures that grow under steady state conditions, two-<span class="hlt">phase</span> microstructures in a peritectic system often evolve under non-steady-state conditions that can lead to oscillatory microstructures, and (2) the microstructure is often governed by both the nucleation and the competitive <span class="hlt">growth</span> of the two <span class="hlt">phases</span> in which repeated nucleation can occur due to the change in the local conditions during <span class="hlt">growth</span>. In this research, experimental studies in the Sn-Cd system were designed to isolate the effects of nucleation and competitive <span class="hlt">growth</span> on the dynamics of complex microstructure formation. Experiments were carried out in capillary samples to obtain diffusive <span class="hlt">growth</span> conditions so that the results can be analyzed quantitatively. At high thermal gradient and low velocity, oscillatory microstructures were observed in which repeated nucleation of the two <span class="hlt">phases</span> was observed at the wall-solid-liquid junction. Quantitative measurements of nucleation undercooling were obtained for both the primary and the peritectic <span class="hlt">phase</span> nucleation, and three different ampoule materials were used to examine the effect of different contact angles at the wall on nucleation undercooling. Nucleation undercooling for each <span class="hlt">phase</span> was found to be very small, and the experimental undercooling values were orders of magnitude smaller than that predicted by the classical theory of nucleation. A new nucleation mechanism is proposed in which the clusters of atoms at the wall ahead of the interface can become a critical nucleus when the cluster encounters the triple junction. Once the nucleation of a new <span class="hlt">phase</span> occurs, the microstructure is found to be controlled by the relative <span class="hlt">growth</span> of the two <span class="hlt">phases</span> that give rise to different</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11985962','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11985962"><span>Immunogenic protein variations of Clostridium chauvoei cellular antigens associated with the culture <span class="hlt">growth</span> <span class="hlt">phase</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mattar, María Aída; Cortiñas, Teresa Inés; de Guzmán, Ana María Stefanini</p> <p>2002-03-25</p> <p>The immunoprotective capacity of four Clostridium chauvoei strains at different <span class="hlt">growth</span> stages is reported. In all the strains tested, the cells coming from the stationary <span class="hlt">phase</span> were those with the highest immunoprotective capacity and, depending on the strain, this protective capacity diminished or even disappeared in other <span class="hlt">phases</span>. Protein profiles were similar in all the strains and few proteins were differentially expressed during <span class="hlt">growth</span> as shown by SDS-PAGE. For strain 17, a local strain, a clear relationship was observed between the diminution of immunogenicity and the total loss of protective capacity of sonicated cells at late stationary <span class="hlt">phase</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18193910','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18193910"><span><span class="hlt">Phase</span> diagram of nanoscale alloy particles used for vapor-liquid-solid <span class="hlt">growth</span> of semiconductor nanowires.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sutter, Eli; Sutter, Peter</p> <p>2008-02-01</p> <p>We use transmission electron microscopy observations to establish the parts of the <span class="hlt">phase</span> diagram of nanometer sized Au-Ge alloy drops at the tips of Ge nanowires (NWs) that determine their temperature-dependent equilibrium composition and, hence, their exchange of semiconductor material with the NWs. We find that the <span class="hlt">phase</span> diagram of the nanoscale drop deviates significantly from that of the bulk alloy, which explains discrepancies between actual <span class="hlt">growth</span> results and predictions on the basis of the bulk-<span class="hlt">phase</span> equilibria. Our findings provide the basis for tailoring vapor-liquid-solid <span class="hlt">growth</span> to achieve complex one-dimensional materials geometries.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28093197','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28093197"><span>Influence of the bacterial <span class="hlt">growth</span> <span class="hlt">phase</span> on the magnetic properties of magnetosomes synthesized by Magnetospirillum gryphiswaldense.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Marcano, L; García-Prieto, A; Muñoz, D; Fernández Barquín, L; Orue, I; Alonso, J; Muela, A; Fdez-Gubieda, M L</p> <p>2017-06-01</p> <p>The magnetosome biosynthesis is a genetically controlled process but the physical properties of the magnetosomes can be slightly tuned by modifying the bacterial <span class="hlt">growth</span> conditions. We designed two time-resolved experiments in which iron-starved bacteria at the mid-logarithmic <span class="hlt">phase</span> are transferred to Fe-supplemented medium to induce the magnetosomes biogenesis along the exponential <span class="hlt">growth</span> or at the stationary <span class="hlt">phase</span>. We used flow cytometry to determine the cell concentration, transmission electron microscopy to image the magnetosomes, DC and AC magnetometry methods for the magnetic characterization, and X-ray absorption spectroscopy to analyze the magnetosome structure. When the magnetosomes synthesis occurs during the exponential <span class="hlt">growth</span> <span class="hlt">phase</span>, they reach larger sizes and higher monodispersity, displaying a stoichiometric magnetite structure, as fingerprinted by the well defined Verwey temperature. On the contrary, the magnetosomes synthesized at the stationary <span class="hlt">phase</span> reach smaller sizes and display a smeared Verwey transition, that suggests that these magnetosomes may deviate slightly from the perfect stoichiometry. Magnetosomes magnetically closer to stoichiometric magnetite are obtained when bacteria start synthesizing them at the exponential <span class="hlt">growth</span> <span class="hlt">phase</span> rather than at the stationary <span class="hlt">phase</span>. The <span class="hlt">growth</span> conditions influence the final properties of the biosynthesized magnetosomes. This article is part of a Special Issue entitled "Recent Advances in Bionanomaterials" Guest Editors: Dr. Marie-Louise Saboungi and Dr. Samuel D. Bader. Copyright © 2017 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26868257','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26868257"><span>Change in Photosystem II Photochemistry During Algal <span class="hlt">Growth</span> <span class="hlt">Phases</span> of Chlorella vulgaris and Scenedesmus obliquus.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Oukarroum, Abdallah</p> <p>2016-06-01</p> <p>Sensitivity of photosynthetic processes towards environmental stress is used as a bioanalytical tool to evaluate the responses of aquatic plants to a changing environment. In this paper, change of biomass density, chlorophyll a fluorescence and photosynthetic parameters during <span class="hlt">growth</span> <span class="hlt">phases</span> of two microalgae Chlorella vulgaris and Scenedesmus obliquus were studied. The photosynthetic <span class="hlt">growth</span> behaviour changed significantly with cell age and algae species. During the exponential <span class="hlt">phase</span> of <span class="hlt">growth</span>, the photosynthesis capacity reached its maximum and decreased in ageing algal culture during stationary <span class="hlt">phase</span>. In conclusion, the chlorophyll a fluorescence OJIP method and the derived fluorescence parameters would be an accurate method for obtaining information on maximum photosynthetic capacities and monitoring algal cell <span class="hlt">growth</span>. This will contribute to more understanding, for example, of toxic actions of pollutants in microalgae test.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3079769','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3079769"><span>2D motility tracking of Pseudomonas putida KT2440 in <span class="hlt">growth</span> <span class="hlt">phases</span> using video microscopy</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Davis, Michael L.; Mounteer, Leslie C.; Stevens, Lindsey K.; Miller, Charles D.; Zhou, Anhong</p> <p>2011-01-01</p> <p>Pseudomonas putida KT2440 is a gram negative motile soil bacterium important in bioremediation and biotechnology. Thus, it is important to understand its motility characteristics as individuals and in populations. Population characteristics were determined using a modified Gompertz model. Video microscopy and imaging software were utilized to analyze two dimensional (2D) bacteria movement tracks to quantify individual bacteria behavior. It was determined that inoculum density increased the lag time as seeding densities decreased, and that the maximum specific <span class="hlt">growth</span> rate decreased as seeding densities increased. Average bacterial velocity remained relatively similar throughout exponential <span class="hlt">growth</span> <span class="hlt">phase</span> (~20.9 µm/sec), while maximum velocities peak early in exponential <span class="hlt">growth</span> <span class="hlt">phase</span> at a velocity of 51.2 µm/sec. Pseudomonas putida KT2440 also favor smaller turn angles indicating they often continue in the same direction after a change in flagella rotation throughout the exponential <span class="hlt">growth</span> <span class="hlt">phase</span>. PMID:21334971</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26265486','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26265486"><span>Gas-<span class="hlt">phase</span> dynamics in graphene <span class="hlt">growth</span> by chemical vapour deposition.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Gan; Huang, Sheng-Hong; Li, Zhenyu</p> <p>2015-09-21</p> <p>Chemical vapour deposition on a Cu substrate is becoming a very important approach to obtain high quality graphene samples. Previous studies of graphene <span class="hlt">growth</span> on Cu mainly focus on surface processes. However, recent experiments suggest that gas-<span class="hlt">phase</span> dynamics also plays an important role in graphene <span class="hlt">growth</span>. In this article, gas-<span class="hlt">phase</span> processes are systematically studied using computational fluid dynamics. Our simulations clearly show that graphene <span class="hlt">growth</span> is limited by mass transport under ambient pressures while it is limited by surface reactions under low pressures. The carbon deposition rate at different positions in the tube furnace and the concentration of different gas <span class="hlt">phase</span> species are calculated. Our results confirm that the previously realized graphene thickness control by changing the position of the Cu foil is a result of gas-<span class="hlt">phase</span> methane decomposition reactions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850054112&hterms=model+Ising&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmodel%2BIsing','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850054112&hterms=model+Ising&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmodel%2BIsing"><span>Defect-<span class="hlt">phase</span>-dynamics approach to statistical domain-<span class="hlt">growth</span> problem of clock models</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kawasaki, K.</p> <p>1985-01-01</p> <p>The <span class="hlt">growth</span> of statistical domains in quenched Ising-like p-state clock models with p = 3 or more is investigated theoretically, reformulating the analysis of Ohta et al. (1982) in terms of a <span class="hlt">phase</span> variable and studying the dynamics of defects introduced into the <span class="hlt">phase</span> field when the <span class="hlt">phase</span> variable becomes multivalued. The resulting defect/<span class="hlt">phase</span> domain-<span class="hlt">growth</span> equation is applied to the interpretation of Monte Carlo simulations in two dimensions (Kaski and Gunton, 1983; Grest and Srolovitz, 1984), and problems encountered in the analysis of related Potts models are discussed. In the two-dimensional case, the problem is essentially that of a purely dissipative Coulomb gas, with a sq rt t <span class="hlt">growth</span> law complicated by vertex-pinning effects at small t.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850054112&hterms=kawasaki&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dkawasaki','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850054112&hterms=kawasaki&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dkawasaki"><span>Defect-<span class="hlt">phase</span>-dynamics approach to statistical domain-<span class="hlt">growth</span> problem of clock models</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kawasaki, K.</p> <p>1985-01-01</p> <p>The <span class="hlt">growth</span> of statistical domains in quenched Ising-like p-state clock models with p = 3 or more is investigated theoretically, reformulating the analysis of Ohta et al. (1982) in terms of a <span class="hlt">phase</span> variable and studying the dynamics of defects introduced into the <span class="hlt">phase</span> field when the <span class="hlt">phase</span> variable becomes multivalued. The resulting defect/<span class="hlt">phase</span> domain-<span class="hlt">growth</span> equation is applied to the interpretation of Monte Carlo simulations in two dimensions (Kaski and Gunton, 1983; Grest and Srolovitz, 1984), and problems encountered in the analysis of related Potts models are discussed. In the two-dimensional case, the problem is essentially that of a purely dissipative Coulomb gas, with a sq rt t <span class="hlt">growth</span> law complicated by vertex-pinning effects at small t.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1337626','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1337626"><span>Hybrid vapor <span class="hlt">phase</span>-solution <span class="hlt">phase</span> <span class="hlt">growth</span> techniques for improved CZT(S,Se) photovoltaic device performance</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Chang, Liang-Yi; Gershon, Talia S.; Haight, Richard A.; Lee, Yun Seog</p> <p>2016-12-27</p> <p>A hybrid vapor <span class="hlt">phase</span>-solution <span class="hlt">phase</span> CZT(S,Se) <span class="hlt">growth</span> technique is provided. In one aspect, a method of forming a kesterite absorber material on a substrate includes the steps of: depositing a layer of a first kesterite material on the substrate using a vapor <span class="hlt">phase</span> deposition process, wherein the first kesterite material includes Cu, Zn, Sn, and at least one of S and Se; annealing the first kesterite material to crystallize the first kesterite material; and depositing a layer of a second kesterite material on a side of the first kesterite material opposite the substrate using a solution <span class="hlt">phase</span> deposition process, wherein the second kesterite material includes Cu, Zn, Sn, and at least one of S and Se, wherein the first kesterite material and the second kesterite material form a multi-layer stack of the absorber material on the substrate. A photovoltaic device and method of formation thereof are also provided.</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/2017SMaS...26e5006C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SMaS...26e5006C"><span>Monitoring fatigue crack <span class="hlt">growth</span> using nonlinear ultrasonic <span class="hlt">phased</span> array imaging</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cheng, Jingwei; Potter, Jack N.; Croxford, Anthony J.; Drinkwater, Bruce W.</p> <p>2017-05-01</p> <p>Nonlinear imaging techniques have recently emerged which have the potential to detect material degradation and challenging defects, such as closed cracks. This paper describes an investigation into the performance of nonlinear ultrasonic imaging (NUI) for the monitoring of the early stages of fatigue crack <span class="hlt">growth</span>. This technique, in conjunction with conventional array imaging, is applied to the periodic monitoring of steel compact tension specimens subjected to high cycle fatigue loading. The detection limits of these techniques are investigated. Their abilities to localise and detect small cracks are further quantified with the aid of micrography. The results suggest that NUI is more sensitive than conventional ultrasonic imaging to the microscale changes occurring at the early stages of failure, i.e. detectability starts c. 15% of fatigue life. In addition to early detection, the potential for NUI to deliver accurate sizing of fatigue cracks and monitor crack propagation is also presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E.783H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E.783H"><span>Dying Flow Bursts as Generators of the <span class="hlt">Substorm</span> Current Wedge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Haerendel, Gerhard</p> <p>2016-07-01</p> <p>Many theories or conjectures exist on the driver of the <span class="hlt">substorm</span> current wedge, e.g. rerouting of the tail current, current disruption, flow braking, vortex formation, and current sheet collapse. Magnitude, spatial scale, and temporal development of the related magnetic perturbations suggest that the generator is related to the interaction of the flow bursts with the dipolar magnetosphere after onset of reconnection in the near-Earth tail. The question remains whether it is the flow energy that feeds the wedge current or the internal energy of the arriving plasma. In this presentation I argue for the latter. The current generation is attributed to the force exerted by the dipolarized magnetic field of the flow bursts on the preceding layer of high-beta plasma after flow braking. The generator current is the grad-B current at the outer boundary of the compressed high-beta plasma layers. It needs the sequential arrival of several flow bursts to account for duration and magnitude of the ionospheric closure current.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM51E2602H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM51E2602H"><span>Dying Flow Bursts as Generators of the <span class="hlt">Substorm</span> Current Wedge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Haerendel, G.</p> <p>2015-12-01</p> <p>Many theories or conjectures exist on the driver of the <span class="hlt">substorm</span> current wedge, e.g. rerouting of the tail current, current disruption, flow braking, vortex formation, and current sheet collapse. Magnitude, spatial scale, and temporal development of the related magnetic perturbations suggest that the generator is related to the interaction of the flow bursts with the dipolar magnetosphere after onset of reconnection in the near-Earth tail. The question remains whether it is the flow energy that feeds the wedge current or the internal energy of the arriving plasma. In this presentation I argue for the latter. The current generation is attributed to the force exerted by the dipolarized magnetic field of the flow bursts on the preceding layer of high-beta plasma after flow braking. The generator current is the grad-B current at the outer boundary of the compressed high-beta plasma layers. It needs the sequential arrival of several flow bursts to account for duration and magnitude of the ionospheric closure current.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/960703','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/960703"><span>Reconnection in <span class="hlt">substorms</span> and solar flares: analogies and differences</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Birn, Joachim</p> <p>2008-01-01</p> <p>Magnetic reconnection is the crucial process in the release of magnetic energy associated with magnetospheric <span class="hlt">substorms</span> and with solar flares. On the basis of three-dimensional resistive MHD simulations we investigate similarities and differences between the two scenarios. We address in particular mechanisms that lead to the onset of reconnection and on energy release, transport, and conversion mechanisms. Analogous processes might exist in the motion of field line footpoints on the sun and in magnetic flux addition to the magnetotail. In both cases such processes might lead to a loss of neighboring equilibrium, characterized by the formation of very thin embedded current sheet, which acts as trigger for reconnection. We find that Joule (or ohmic) dissipation plays only a minor role in the overall energy transfer associated with reconnection. The dominant transfer of released magnetic energy occurs to electromagnetic energy (Poynting) flux and to thermal energy transport as enthalpy flux. The former dominates in low-beta, specifically initially force-free current sheets expected for the solar corona, while the latter dominates in high-beta current sheets, such as the magnetotail. In both cases the outflow from the reconnection site becomes bursty, i.e. spatially and temporally localized, yet carrying most of the outflow energy. Hence an analogy might exist between bursty bulk flows (BBFs) in the magnetotail and pulses of Poynting flux in solar flares.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFMSM31B1231Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFMSM31B1231Z"><span>Continuous Lobe Reconnection in the Mid-Tail: Observational Signatures and Relation to <span class="hlt">Substorm</span> onset</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, H.; Pu, Z.; Cao, X.; Xiao, C.; Fu, S.</p> <p>2004-12-01</p> <p>Magnetospheric <span class="hlt">substorms</span> represent a global interaction between the solar wind, the magnetosphere, and the ionosphere. Energy extracted from the solar wind is mainly stored in the form of excess magnetic flux in the magnetotail lobes. There is little doubt that reconnection occurs in the magnetotail at some point during <span class="hlt">substorms</span>. However, whether or not explosive release of this energy is required to cause the <span class="hlt">substorm</span> and whether reconnection precedes or succeeds expansion onset are still subjects of big debate and controversy. In past three years (2001-2003) Cluster constellation passed through the plasma sheet more than one hundred times. Base on survey of the three yearAƒÆ'A+â_TAƒâ_sA,AøAƒÆ'A,AøAƒAøAøâ_sA¬A.A¡Aƒâ_sA,A¬AƒÆ'A,AøAƒAøAøâ_sA¬A.A_Aƒâ_sA,Aøs four spacecraft data, we have selected 39 continues lobe reconnection (CLR) events. A careful study of these events indicates that the CLR and plasma sheet closed field line reconnection manifest quite differently. The CLR occurs when the IMF is persistently southward (say, for more than a few tens of minutes) and maintains for more than about 20 minutes. It creates a low-density and low-temperature structure with high-speed plasma flows near the central plasma sheet. Quite often the CLRs appear quasi-periodically and in association with the presence of a magnetic storm. Comprehensive investigations have been made in this paper on the relationship between the occurrence of CLRs in the mid-tail and the <span class="hlt">substorm</span> onsets in the near-Earth region. The 39 CLRs are all found to be corresponding to the appearance of intense <span class="hlt">substorms</span>. In 37 events the CLRs precede <span class="hlt">substorms</span> expansion onsets, while other two are opposite. These suggest that tail lobe unloading via CLR is a critical issue for the expansion onset of <span class="hlt">substorms</span> occurring in persistently southward IMF periods. Nevertheless, this study does not exclude that <span class="hlt">substorms</span> of other types may have different causes and that dynamical</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSM53A..07M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSM53A..07M"><span>Interaction of <span class="hlt">substorm</span> injections with the plasmasphere: A turbulent plasmaspheric 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>Maggiolo, R.; Maes, L.; De Keyser, J.; Haaland, S.; Echim, M.</p> <p>2014-12-01</p> <p>In-situ measurements of plasma, fields, and waves around the plasmasphere's boundary in the evening sector during <span class="hlt">substorm</span> injection events are presented. The data reveal that the cold plasma short-circuits <span class="hlt">substorm</span>-injected hot plasma jets when the cold plasma density exceeds a critical value of 5-10 c.c. The <span class="hlt">substorm</span>-injected hot electrons stop at the pre-<span class="hlt">substorm</span> plasmapause, thereby providing a natural explanation of the long-known dispersionless auroral precipitation boundary. A turbulent plasmaspheric boundary layer forms initially near the pre-<span class="hlt">substorm</span> plasmapause due to interactions between the injected and plasmaspheric populations. The main sources of the greatly-enhanced wave activity are the so-called modified two-stream instability driven by the hot electron diamagnetic drift in the entry layer, ion-ring instability driven by the highly-anisotropic hot ion distribution in the central part, and the diamagnetic drift of hot ions near the inner edge. Enhanced plasma turbulence leads to heating of the cold plasma and to acceleration of suprathermal electron tails, thereby enhancing the downward heat transport and concomitant heating of the ionospheric electrons observed by the DMSP satellites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM53A..07M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM53A..07M"><span>Interaction of <span class="hlt">substorm</span> injections with the plasmasphere: A turbulent plasmaspheric 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>Mishin, E. V.</p> <p>2015-12-01</p> <p>In-situ measurements of plasma, fields, and waves around the plasmasphere's boundary in the evening sector during <span class="hlt">substorm</span> injection events are presented. The data reveal that the cold plasma short-circuits <span class="hlt">substorm</span>-injected hot plasma jets when the cold plasma density exceeds a critical value of 5-10 c.c. The <span class="hlt">substorm</span>-injected hot electrons stop at the pre-<span class="hlt">substorm</span> plasmapause, thereby providing a natural explanation of the long-known dispersionless auroral precipitation boundary. A turbulent plasmaspheric boundary layer forms initially near the pre-<span class="hlt">substorm</span> plasmapause due to interactions between the injected and plasmaspheric populations. The main sources of the greatly-enhanced wave activity are the so-called modified two-stream instability driven by the hot electron diamagnetic drift in the entry layer, ion-ring instability driven by the highly-anisotropic hot ion distribution in the central part, and the diamagnetic drift of hot ions near the inner edge. Enhanced plasma turbulence leads to heating of the cold plasma and to acceleration of suprathermal electron tails, thereby enhancing the downward heat transport and concomitant heating of the ionospheric electrons observed by the DMSP satellites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050169213','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050169213"><span>Energetic Electron Transport in the Inner Magnetosphere During Geomagnetic Storms and <span class="hlt">Substorms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>McKenzie, D. L.; Anderson, P. C.</p> <p>2005-01-01</p> <p>We propose to examine the relationship of geomagnetic storms and <span class="hlt">substorms</span> and the transport of energetic particles in the inner magnetosphere using measurements of the auroral X-ray emissions by PIXIE. PIXIE provides a global view of the auroral oval for the extended periods of time required to study stormtime phenomena. Its unique energy response and global view allow separation of stormtime particle transport driven by strong magnetospheric electric fields from <span class="hlt">substorm</span> particle transport driven by magnetic-field dipolarization and subsequent particle injection. The relative importance of <span class="hlt">substorms</span> in releasing stored magnetospheric energy during storms and injecting particles into the inner magnetosphere and the ring current is currently hotly debated. The distribution of particles in the inner magnetosphere is often inferred from measurements of the precipitating auroral particles. Thus, the global distributions of the characteristics of energetic precipitating particles during storms and <span class="hlt">substorms</span> are extremely important inputs to any description or model of the geospace environment and the Sun-Earth connection. We propose to use PIXIE observations and modeling of the transport of energetic electrons to examine the relationship between storms and <span class="hlt">substorms</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20000093998&hterms=bread&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dbread','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20000093998&hterms=bread&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dbread"><span>Global Remote Sensing of Precipitating Electron Energies: A Comparison of <span class="hlt">Substorms</span> and Pressure Pulse Related Intensifications</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chua, D.; Parks, G. K.; Brittnacher, M. J.; Germany, G. A.; Spann, J. F.</p> <p>2000-01-01</p> <p>The Polar Ultraviolet Imager (UVI) observes aurora responses to incident solar wind pressure pulses and interplanetary shocks such its those associated with coronal mass ejections. Previous observations have demonstrated that the arrival of it pressure pulse at the front of the magnetosphere results in highly disturbed geomagnetic conditions and a substantial increase in both dayside and nightside aurora precipitations. Our observations show it simultaneous brightening over bread areas of the dayside and nightside auroral in response to a pressure pulse, indicating that more magnetospheric regions participate as sources for auroral precipitation than during isolate <span class="hlt">substorm</span>. We estimate the characteristic energies of incident auroral electrons using Polar UVI images and compare the precipitation energies during pressure pulse associated event to those during isolated <span class="hlt">substorms</span>. We estimate the characteristic energies of incident auroral electrons using Polar UVI images and compare the precipitation energies during pressure pulse associated events to those during isolated auroral <span class="hlt">substorms</span>. Electron precipitation during <span class="hlt">substorms</span> has characteristic energies greater than 10 KeV and is structured both in local time and in magnetic latitude. For auroral intensifications following the arrival of'a pressure pulse or interplanetary shock. Electron precipitation is less spatially structured and has greater flux of lower characteristic energy electrons (Echar less than 7 KeV) than during isolated <span class="hlt">substorm</span> onsets. These observations quantify the differences between global and local auroral precipitation processes and will provide a valuable experimental check for models of sudden storm commencements and magnetospheric response to perturbations in the solar wind.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120..253C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120..253C"><span>Magnetic mapping effects of <span class="hlt">substorm</span> currents leading to auroral poleward expansion and equatorward retreat</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chu, Xiangning; McPherron, Robert L.; Hsu, Tung-Shin; Angelopoulos, Vassilis; Pu, Zuyin; Yao, Zhonghua; Zhang, Hui; Connors, Martin</p> <p>2015-01-01</p> <p>fast flows, magnetic field dipolarization, and its relaxation are linked to auroral brightening, poleward expansion, and equatorward motion during <span class="hlt">substorm</span> onset, expansion, and recovery, respectively. While auroral brightening is often attributed to the field-aligned currents produced by flow vorticity and pressure redistribution, the physical causes of auroral poleward expansion and equatorward retreat are not fully understood. Simplistically, such latitudinal changes can be directly associated to the tailward motion of the flux pileup region and the earthward flux transport toward the dayside that depletes the near-Earth plasma sheet. However, because the equatorial magnetic field profile and the magnetospheric field-aligned current system change significantly, mapping is severely distorted. To investigate this distortion, we superimpose a <span class="hlt">substorm</span> current wedge model (dynamically driven by ground-based observations) on the global Tsyganenko model T96 during an isolated <span class="hlt">substorm</span> on 13 February 2008, observed by the Time History of Events and Macroscale Interactions during <span class="hlt">Substorms</span> and GOES 10 spacecraft and by ground all-sky imagers. We validate our model by showing that the timing and ionospheric projection of the flux pileup region and flow bursts observed at the spacecraft match auroral activations. We then use the improved mapping enabled by the model to demonstrate that in this event, auroral poleward expansion and equatorward retreat are mainly caused by <span class="hlt">substorm</span>-current-wedge-induced mapping changes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20000093998&hterms=bread&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dbread','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20000093998&hterms=bread&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dbread"><span>Global Remote Sensing of Precipitating Electron Energies: A Comparison of <span class="hlt">Substorms</span> and Pressure Pulse Related Intensifications</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chua, D.; Parks, G. K.; Brittnacher, M. J.; Germany, G. A.; Spann, J. F.</p> <p>2000-01-01</p> <p>The Polar Ultraviolet Imager (UVI) observes aurora responses to incident solar wind pressure pulses and interplanetary shocks such its those associated with coronal mass ejections. Previous observations have demonstrated that the arrival of it pressure pulse at the front of the magnetosphere results in highly disturbed geomagnetic conditions and a substantial increase in both dayside and nightside aurora precipitations. Our observations show it simultaneous brightening over bread areas of the dayside and nightside auroral in response to a pressure pulse, indicating that more magnetospheric regions participate as sources for auroral precipitation than during isolate <span class="hlt">substorm</span>. We estimate the characteristic energies of incident auroral electrons using Polar UVI images and compare the precipitation energies during pressure pulse associated event to those during isolated <span class="hlt">substorms</span>. We estimate the characteristic energies of incident auroral electrons using Polar UVI images and compare the precipitation energies during pressure pulse associated events to those during isolated auroral <span class="hlt">substorms</span>. Electron precipitation during <span class="hlt">substorms</span> has characteristic energies greater than 10 KeV and is structured both in local time and in magnetic latitude. For auroral intensifications following the arrival of'a pressure pulse or interplanetary shock. Electron precipitation is less spatially structured and has greater flux of lower characteristic energy electrons (Echar less than 7 KeV) than during isolated <span class="hlt">substorm</span> onsets. These observations quantify the differences between global and local auroral precipitation processes and will provide a valuable experimental check for models of sudden storm commencements and magnetospheric response to perturbations in the solar wind.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005JCrGr.279..213K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005JCrGr.279..213K"><span>Numerical simulation of liquid <span class="hlt">phase</span> electro-epitaxial selective area <span class="hlt">growth</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Khenner, M.; Braun, R. J.</p> <p>2005-05-01</p> <p>A computational model for semiconductor crystal <span class="hlt">growth</span> on a partially masked substrate under simplified liquid <span class="hlt">phase</span> electroepitaxy conditions is developed. The model assumes isothermal diffusional <span class="hlt">growth</span>, which is enhanced by applied DC current through crystal-solution interface. A finite-difference, front-tracking method is used to numerically evolve the interface. Computed examples show strong influence of the electromigration on <span class="hlt">growth</span> rates in vertical and lateral directions and the dependence of <span class="hlt">growth</span> on electrical resistance of mask material, and on the wetting contact angle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6880485','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6880485"><span>Radiosensitivity of different tissues from carrot root at different <span class="hlt">phases</span> of <span class="hlt">growth</span> in culture</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Degani, N.; Pickholtz, D.</p> <p>1980-09-01</p> <p>The present work compares the effect of ..gamma..-radiation dose and time in culture on the <span class="hlt">growth</span> of cambium and phloem carrot (Daucus carota) root explants. It was found that the phloem is more radiosensitive than the cambium and that both tissues were more radiosensitive when irradiated on excision at the G/sub 1/ <span class="hlt">phase</span> rather than at the end of the lag <span class="hlt">phase</span> on the ninth day of <span class="hlt">growth</span> in culture when cells were predominantly at the G/sub 2/ <span class="hlt">phase</span>. The nuclear volumes of cells from both tissues were similar but were larger at the end of the more radioresistant lag <span class="hlt">phase</span>