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Title: The relativistic electron response at geosynchronous orbit during the January 1997 magnetic storm

Abstract

The first geomagnetic storm of 1997 began on January 10. It is of particular interest because it was exceptionally well observed by the full complement of International Solar Terrestrial Physics (ISTP) satellites and because of its possible association with the catastrophic failure of the Telstar 401 telecommunications satellite. Here we report on the energetic electron environment observed by five geosynchronous satellites. In part one of this paper we examine the magnetospheric response to the magnetic cloud. The interval of southward IMF drove strong substorm activity while the interval of northward IMF and high solar wind density strongly compressed the magnetosphere. At energies above a few hundred keV, two distinct electron enhancements were observed at geosynchronous orbit. The first enhancement began and ended suddenly, lasted for approximately 1 day, and is associated with the strong compression of the magnetosphere. The second enhancement showed a more characteristic time delay, peaking on January 15. Both enhancements may be due to transport of electrons from the same initial acceleration event at a location inside geosynchronous orbit but the first enhancement was due to a temporary, quasi-adiabatic transport associated with the compression of the magnetosphere while the second enhancement was due to slower diffusive processes.more » In the second part of the paper we compare the relativistic electron fluxes measured simultaneously at different local times. We find that the {gt}2-MeV electron fluxes increased first at noon followed by dusk and then dawn and that there can be difference of two orders of magnitude in the fluxes observed at different local times. Finally, we discuss the development of data-driven models of the relativistic electron belts for space weather applications. By interpolating fluxes between satellites we produced a model that gives the {gt}2-MeV electron fluxes at all local times as a function of universal time. In a first application of this model we show that, at least in this case, magnetopause shadowing does not contribute noticeably to relativistic electron dropouts. {copyright} 1998 American Geophysical Union« less

Authors:
; ; ; ;  [1]; ;  [2]; ;  [3]
  1. Los Alamos National Laboratory, Los Alamos, New Mexico (United States) [Department of Physics Astronomy, University of Maryland, College Park (United States)
  2. NOAA Space Environment Center, Boulder, Colorado (United States)
  3. Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado (United States)
Publication Date:
OSTI Identifier:
298592
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Geophysical Research; Journal Volume: 103; Journal Issue: A8; Other Information: PBD: Aug 1998
Country of Publication:
United States
Language:
English
Subject:
66 PHYSICS; MAGNETIC STORMS; SOLAR WIND; EARTH MAGNETOSPHERE; RELATIVISTIC PLASMA; SATELLITES

Citation Formats

Reeves, G.D., Friedel, R.H., Belian, R.D., Meier, M.M., Henderson, M.G., Onsager, T., Singer, H.J., Baker, D.N., and Li, X. The relativistic electron response at geosynchronous orbit during the January 1997 magnetic storm. United States: N. p., 1998. Web. doi:10.1029/97JA03236.
Reeves, G.D., Friedel, R.H., Belian, R.D., Meier, M.M., Henderson, M.G., Onsager, T., Singer, H.J., Baker, D.N., & Li, X. The relativistic electron response at geosynchronous orbit during the January 1997 magnetic storm. United States. doi:10.1029/97JA03236.
Reeves, G.D., Friedel, R.H., Belian, R.D., Meier, M.M., Henderson, M.G., Onsager, T., Singer, H.J., Baker, D.N., and Li, X. 1998. "The relativistic electron response at geosynchronous orbit during the January 1997 magnetic storm". United States. doi:10.1029/97JA03236.
@article{osti_298592,
title = {The relativistic electron response at geosynchronous orbit during the January 1997 magnetic storm},
author = {Reeves, G.D. and Friedel, R.H. and Belian, R.D. and Meier, M.M. and Henderson, M.G. and Onsager, T. and Singer, H.J. and Baker, D.N. and Li, X.},
abstractNote = {The first geomagnetic storm of 1997 began on January 10. It is of particular interest because it was exceptionally well observed by the full complement of International Solar Terrestrial Physics (ISTP) satellites and because of its possible association with the catastrophic failure of the Telstar 401 telecommunications satellite. Here we report on the energetic electron environment observed by five geosynchronous satellites. In part one of this paper we examine the magnetospheric response to the magnetic cloud. The interval of southward IMF drove strong substorm activity while the interval of northward IMF and high solar wind density strongly compressed the magnetosphere. At energies above a few hundred keV, two distinct electron enhancements were observed at geosynchronous orbit. The first enhancement began and ended suddenly, lasted for approximately 1 day, and is associated with the strong compression of the magnetosphere. The second enhancement showed a more characteristic time delay, peaking on January 15. Both enhancements may be due to transport of electrons from the same initial acceleration event at a location inside geosynchronous orbit but the first enhancement was due to a temporary, quasi-adiabatic transport associated with the compression of the magnetosphere while the second enhancement was due to slower diffusive processes. In the second part of the paper we compare the relativistic electron fluxes measured simultaneously at different local times. We find that the {gt}2-MeV electron fluxes increased first at noon followed by dusk and then dawn and that there can be difference of two orders of magnitude in the fluxes observed at different local times. Finally, we discuss the development of data-driven models of the relativistic electron belts for space weather applications. By interpolating fluxes between satellites we produced a model that gives the {gt}2-MeV electron fluxes at all local times as a function of universal time. In a first application of this model we show that, at least in this case, magnetopause shadowing does not contribute noticeably to relativistic electron dropouts. {copyright} 1998 American Geophysical Union},
doi = {10.1029/97JA03236},
journal = {Journal of Geophysical Research},
number = A8,
volume = 103,
place = {United States},
year = 1998,
month = 8
}
  • Radiation-belt relativistic (E > 0.6, > 2.0, and > 4.0 MeV) electron acceleration is studied for solar cycle 23 (1995-2008). High-intensity, long-duration, continuous AE activity (HILDCAA) events are considered as the basis of the analyses. All of the 35 HILDCAA events under study were found to be characterized by flux enhancements of magnetospheric relativistic electrons of all three energies compared to the pre-event flux levels. For the E > 2.0 MeV electron fluxes, enhancement of >50% occurred during 100% of HILDCAAs. Cluster-4 passes were examined for electromagnetic chorus waves in the 5 < L < 10 and 0 < MLT < 12more » region when wave data were available. Fully 100% of these HILDCAA cases were associated with enhanced whistler-mode chorus waves. The enhancements of E > 0.6, > 2.0, and > 4.0 MeV electrons occurred ∼1.0 day, ∼1.5 days, and ∼2.5 days after the statistical HILDCAA onset, respectively. The statistical acceleration rates for the three energy ranges were ∼1.8 × 10{sup 5}, 2.2 × 10{sup 3}, and 1.0 × 10{sup 1} cm{sup –2} s{sup –1} sr{sup –1} d{sup –1}, respectively. The relativistic electron-decay timescales were determined to be ∼7.7, 5.5, and 4.0 days for the three energy ranges, respectively. The HILDCAAs were divided into short-duration (D ≤ 3 days) and long-duration (D > 3 days) events to study the dependence of relativistic electron variation on HILDCAA duration. For long-duration events, the flux enhancements during HILDCAAs with respect to pre-event fluxes were ∼290%, 520%, and 82% for E > 0.6, > 2.0, and > 4.0 MeV electrons, respectively. The enhancements were ∼250%, 400%, and 27% respectively, for short-duration events. The results are discussed with respect to the current understanding of radiation-belt dynamics.« less
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