Biblio

Found 8 results
Filters: Keyword is Substorm Injections  [Clear All Filters]
2018
Authors: Tang C. L., Xie X. J., Ni B, Su Z. P., Reeves G D, et al.
Title: Rapid Enhancements of the Seed Populations in the Heart of the Earth's Outer Radiation Belt: A Multicase Study
Abstract: To better understand rapid enhancements of the seed populations (hundreds of keV electrons) in the heart of the Earth's outer radiation belt (L* ~ 3.5–5.0) during different geomagnetic activities, we investigate three enhancement events measured by Van Allen Probes in detail. Observations of the fluxes and the pitch angle distributions of energetic electrons are analyzed to determine rapid enhancements of the seed populations. Our study shows that three specified processes associated with substorm electron injections can lead to rapid enhancements of the seed populations, and the electron energy increases up to 342 keV. In the first process, substorm electron injections accompanied by the transient and intense substorm electric fields can directly lead to rapid enhancements of the seed p. . .
Date: 06/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2017JA025142 Available at: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2017JA025142
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2017
Authors: Tang C. L., Wang Y. X., Ni B, Zhang J.-C., Reeves G D, et al.
Title: Radiation belt seed population and its association with the relativistic electron dynamics: A statistical study
Abstract: Using the particle data measured by Van Allen Probe A from October 2012 to March 2016, we investigate in detail the radiation belt seed population and its association with the relativistic electron dynamics during 74 geomagnetic storms. The period of the storm recovery phase was limited to 72 h. The statistical study shows that geomagnetic storms and substorms play important roles in the radiation belt seed population (336 keV electrons) dynamics. Based on the flux changes of 1 MeV electrons before and after the storm peak, these storm events are divided into two groups of “large flux enhancement” and “small flux enhancement.” For large flux enhancement storm events, the correlation coefficients between the peak flux location of the seed population and those of relativistic electro. . .
Date: 05/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA023905 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA023905/full
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2014
Authors: Yu Yiqun, Jordanova Vania, Welling Dan, Larsen Brian, Claudepierre Seth G., et al.
Title: The role of ring current particle injections: Global simulations and Van Allen Probes observations during 17 March 2013 storm
Abstract: We simulate substorm injections observed by the Van Allen Probes during the 17 March 2013 storm using a self-consistent coupling between the ring current model RAM-SCB and the global MHD model BATS-R-US. This is a significant advancement compared to previous studies that used artificially imposed electromagnetic field pulses to mimic substorm dipolarization and associated inductive electric field. Several substorm dipolarizations and injections are reproduced in the MHD model, in agreement with the timing of shape changes in the AE/AL index. The associated inductive electric field transports plasma sheet plasma to geostationary altitudes, providing the boundary plasma source to the ring current model. It is found that impulsive plasma sheet injections, together with a large-scale convectio. . .
Date: 02/2014 Publisher: Geophysical Research Letters Pages: 1126 - 1132 DOI: 10.1002/2014GL059322 Available at: http://doi.wiley.com/10.1002/2014GL059322
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2010
Authors: Min Kyungguk, Lee Jeongwoo, and Keika Kunihiro
Title: Chorus wave generation near the dawnside magnetopause due to drift shell splitting of substorm-injected electrons
Abstract: We study the relationship between the electron injection and the chorus waves during a substorm event on 23 March 2007. The chorus waves were detected at high geomagnetic latitude (∼70°S) Antarctic observatories in the range of 0600–0900 h in magnetic local time (MLT). Electrons drifting from the injection event were measured by two LANL spacecraft at 0300 and 0900 MLT. The mapping of auroral brightening areas to the magnetic equator shows that the injection occurred in an MLT range of 2200–2400. This estimate is consistent with observations by the THEMIS A, B, and D spacecraft (which were located at 2100 MLT and did not observe electron injections). Our backward model tracing from the magnetic equator near the dawnside magnetopause (which magnetically connects to the Antar. . .
Date: 10/2010 Publisher: American Geophysical Union DOI: 10.1029/2010JA015474
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2005
Authors: Mithaiwala M J, and Horton W.
Title: Substorm injections produce sufficient electron energization to account for MeV flux enhancements following some storms
Abstract: One of the main questions concerning radiation belt research is the origin of very high energy (>1 MeV) electrons following many space storms. Under the hypothesis that the plasma sheet electron population is the source of these electrons, which are convected to the outer radiation belt region during substorms, we estimate the flux of particles generated at geosynchronous orbit. We use the test particle method of following guiding center electrons as they drift in the electromagnetic fields during substorm dipolarization. The dipolarization pulse model electromagnetic fields are taken from the Li et al. (1998) substorm particle injection model. We find that a substorm dipolarization can produce enough electrons within geosynchronous orbit to account for the electrons seen following storms.. . .
Date: 07/2005 Publisher: Journal of Geophysical Research DOI: 10.1029/2004JA010511 Available at: http://onlinelibrary.wiley.com/doi/10.1029/2004JA010511/abstract
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2001
Authors: Ingraham J C, Cayton T E, Belian R D, Christensen R A, Friedel R H W, et al.
Title: Substorm injection of relativistic electrons to geosynchronous orbit during the great magnetic storm of March 24, 1991
Abstract: The great March 1991 magnetic storm and the immediately preceding solar energetic particle event (SEP) were among the largest observed during the past solar cycle, and have been the object of intense study. We investigate here, using data from eight satellites, the very large delayed buildup of relativistic electron flux in the outer zone during a 1.5-day period beginning 2 days after onset of the main phase of this storm. A notable feature of the March storm is the intense substorm activity throughout the period of the relativistic flux buildup, and the good correlation between some temporal features of the lower-energy substorm-injected electron flux and the relativistic electron flux at geosynchronous orbit. Velocity dispersion analysis of these fluxes between geosynchronous satellites . . .
Date: 11/2001 Publisher: Journal of Geophysical Research Pages: 25759 - 25776 DOI: 10.1029/2000JA000458 Available at: http://onlinelibrary.wiley.com/doi/10.1029/2000JA000458/full
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2000
Authors: Meredith Nigel P, Horne Richard B, Johnstone Alan D, and Anderson Roger R
Title: The temporal evolution of electron distributions and associated wave activity following substorm injections in the inner magnetosphere
Abstract: The temporal evolution of electron distributions and associated wave activity following substorm injections in the inner magnetosphere are investigated using data from the CRRES satellite. Equatorial electron distributions and concomitant wave spectra outside the plasmapause on the nightside of the Earth are studied as a function of time since injection determined from the auroral-electrojet index (AE). The electron cyclotron harmonic (ECH) wave amplitudes are shown to be very sensitive to small modeling errors in the location of the magnetic equator. They are best understood at the ECH equator, defined by the local maximum in the ECH wave activity in the vicinity of the nominal magnetic equator, suggesting that the ECH equator is a better measure of the location of the true equator. Stron. . .
Date: 06/2000 Publisher: Journal of Geophysical Research Pages: 12907 DOI: 10.1029/2000JA900010 Available at: http://onlinelibrary.wiley.com/doi/10.1029/2000JA900010/full
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1998
Authors: Birn J, Thomsen M F, Borovsky J E, Reeves G D, McComas D J, et al.
Title: Substorm electron injections: Geosynchronous observations and test particle simulations
Abstract: We investigate electron acceleration and the flux increases associated with energetic electron injections on the basis of geosynchronous observations and test-electron orbits in the dynamic fields of a three-dimensional MHD simulation of neutral line formation and dipolarization in the magnetotail. This complements an earlier investigation of test protons [Birn et al., 1997b]. In the present paper we consider equatorial orbits only, using the gyrocenter drift approximation. It turns out that this approximation is valid for electrons prior to and during the flux rises observed in the near tail region of the model at all energies considered (∼ 100 eV to 1 MeV). The test particle model reproduces major observed characteristics: a fast flux rise, comparable to that of the ions, and the exist. . .
Date: 05/1998 Publisher: Journal of Geophysical Research Pages: 9235 - 9248 DOI: 10.1029/97JA02635 Available at: http://onlinelibrary.wiley.com/doi/10.1029/97JA02635/abstract
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