HR: 17:30h
AN: SM34A-07    [Abstracts]
TI: Relativistic electron loss measurements from the LANL GPS energetic particle instruments.
AU: * Friedel, R H
EM: friedel@lanl.gov
AF: Los Alamos National Laboratory, Space and Atmospheric Sciences ISR-1 MS D466, Los Alamos, NM 87544 United States
AU: Koller, J
EM: jkoller@lanl.gov
AF: Los Alamos National Laboratory, Space and Atmospheric Sciences ISR-1 MS D466, Los Alamos, NM 87544 United States
AU: Cayton, T E
EM: tcayton@lanl.gov
AF: Los Alamos National Laboratory, Space and Atmospheric Sciences ISR-1 MS D466, Los Alamos, NM 87544 United States
AU: Green, J C
EM: Janet.Green@lasp.colorado.edu
AF: University Colorado/LASP, 1234 Innovation Dr, Boulder, CO 80303 United States
AU: O'Brien, T P
EM: paul.obrien@aero.org
AF: The Aerospace Corporation, M2-260 PO Box 92957, Los Angeles, CA 90009-2957 United States
AU: Onsager, T G
EM: terry.onsager@noaa.gov
AF: NOAA R/E/SE, 325 Broadway, Boulder, CO 80305 United States
AB: In a recent study Green et al. performed a superposed epoch study of 52 relativistic electron loss events as measured by the LANL geosynchronous satellites and posed a basic question: "Where did all the relativistic electrons go?" Their study covered weakly disturbed times ($DST>-60$) and indicated an initial adiabatic response followed by permanent loss at geosynchronous. Losses as deep as $L=4$ and no proton losses rule out magnetopause shadowing, leaving precipitation losses due to wave particle interactions as a likely candidate. We use here the dense coverage of the LANL GPS energetic particle instrument constellation to perform a superposed epoch study of the same set of events. The GPS satellites cover the region from L=4 outward every three hours. Using two inter-calibrated GPS satellites (ns24 and ns33) enables us to achieve both a high time resolution on the L=dependent loss timescales. Initial results indicate that for higher L and lower energies ($L \sim 5-6$, $E \sim 300$ KeV) losses occur quickly over a period of 3-9 hours, while at lower $L$ ($L \sim 4$) and higher energies ($E \sim 2$ MeV) the rates are longer, 8--24 hours. We will attempt to use the local time information from our constellation to identify in which local time regions these losses occur first or are more severe, which will enable us to test some of the current theories for these losses (EMIC or whistler waves?).
DE: 2716 Energetic particles, precipitating
DE: 2720 Energetic particles, trapped
DE: 2730 Magnetosphere--inner
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting