HR: 08:30h
AN: SM51D-03    [Abstracts]
TI: Radiation Belt Loss at the Magnetopause
AU: * Onsager, T G
EM: terry.onsager@noaa.gov
AF: NOAA Space Environment Center, 325 Broadway, Boulder, CO 80305 United States
AU: Green, J C
EM: janet.green@noaa.gov
AF: NOAA Space Environment Center, 325 Broadway, Boulder, CO 80305 United States
AU: Singer, H J
EM: howard.singer@noaa.gov
AF: NOAA Space Environment Center, 325 Broadway, Boulder, CO 80305 United States
AU: Reeves, G D
EM: reeves@lanl.gov
AF: Los Alamos National Laboratory, MS D466, Los Alamos, NM 87545
AU: Bourdarie, S
EM: sebastien.bourdarie@onecert.fr
AF: Centre d'Etudes et de Recherches de Toulouse, Departement Environnement Spatial, Toulouse, 31055 France
AB: A critical factor controlling the dynamics of the outer electron radiation belt is the abrupt electron loss from the magnetosphere that frequently occurs. Although the major loss mechanisms are known to be transport out across the magnetopause and precipitation into the atmosphere, it is not known quantitatively how effective either of these mechanisms is under any set of circumstances. It is thought that a compression of the magnetopause should cause a reduction of the electron fluxes at the larger L shells, but it is not known what the magnitude of the flux reduction should be. In this study, we investigate the depletion of radiation belt electron flux associated with the compression of the magnetopause to inside geosynchronous orbit. Multiple geosynchronous satellites are used to determine the local-time dependence of the flux dropouts. A clear local-time dependence is observed as the flux decreases during the earthward compression of the magnetopause and during the recovery of the flux as the magnetopause expands back outward. Surprisingly, the flux recovers immediately to levels moderately below the original flux levels with the relaxation of the magnetopause to outside geosynchronous orbit. These results are used to quantify the loss of radiation belt electrons due to the inward motion of the magnetopause and the subsequent recovery.
DE: 2720 Energetic particles: trapped
DE: 2724 Magnetopause and boundary layers
DE: 2774 Radiation belts
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005