ENERGETIC ELECTRONS AT GEOSTATIONARY ORBIT DURING THE NOVEMBER 3-4, 1993 STORM - SPATIAL TEMPORAL MORPHOLOGY, CHARACTERIZATION BY A POWER-LAW SPECTRUM AND, REPRESENTATION BY AN ARTIFICIAL NEURAL-NETWORK/

Citation
Jw. Freeman et al., ENERGETIC ELECTRONS AT GEOSTATIONARY ORBIT DURING THE NOVEMBER 3-4, 1993 STORM - SPATIAL TEMPORAL MORPHOLOGY, CHARACTERIZATION BY A POWER-LAW SPECTRUM AND, REPRESENTATION BY AN ARTIFICIAL NEURAL-NETWORK/, J GEO R-S P, 103(A11), 1998, pp. 26251-26260
Citations number
23
Categorie Soggetti
Geosciences, Interdisciplinary","Astronomy & Astrophysics","Metereology & Atmospheric Sciences",Oceanografhy,"Geochemitry & Geophysics
Journal title
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
ISSN journal
21699380 → ACNP
Volume
103
Issue
A11
Year of publication
1998
Pages
26251 - 26260
Database
ISI
SICI code
2169-9380(1998)103:A11<26251:EEAGOD>2.0.ZU;2-X
Abstract
Electrons of energy several MeV or greater have been implicated in the failure and malfunction of geostationary spacecraft. It is therefore important to be able to specify and even forecast the fluxes of these particles during and following geomagnetic storms. A first step is the understanding of their relationship to lower-energy electrons that ca n already be well modeled. It is therefore the goal of this paper to e xamine the relative time, spatial, and spectral relationships between 1.5 MeV electrons and intermediate energy electrons down to about 100 keV. For the November 1993 geomagnetic storm we find that electrons fr om about 100 keV to 1.5 MeV at GEO can be conveniently characterized b y a power law spectrum and that the slope and intercept of this spectr um vary in systematic ways during the storm. This suggests the possibi lity of developing prediction filters or artificial neural networks, d riven by a storm activity indicator (such as Dst), local time and a lo wer-energy electron flux, to specify the energetic electron spectral c haracteristics. We further find that local time diurnal effects are an important contributor to the apparent time delay of the recovery of e nergetic electrons and when these effects are considered the recovery phase enhancement is nearly uniform across the spectrum. This paper wi ll report the spatial and temporal morphology of these intermediate to energetic electrons, their characterization by a power law and the va riations of the power law slope and intercept throughout the November 1993 storm. These temporal, spatial, and spectral properties suggest t hat the recovery phase enhancement is due to the entry of the intermed iate energy electrons from the geomagnetic tail as part of the storm i njection process. We also discuss our success at building an Artificia l Neural Network system to specify the storm time energetic electron f lux spectra.