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/
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
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.