HR: 10:50h
AN: SM42A-03    [Abstracts]
TI: Source and loss rates of radiation belt relativistic electrons
AU: * Selesnick, R S
EM: richard.s.selesnick@aero.org
AF: The Aerospace Corporation, P.O. Box 92957, Los Angeles, CA 90009 United States
AB: Radiation belt electrons are accelerated to relativistic energies during magnetic storms and also lost by precipitation into the atmosphere. These source and loss processes compete to decide the stably trapped electron intensity. It is therefore desirable for an understanding of the fundamental mechanisms that populate the radiation belt to determine the source and loss rates independently. This is achieved using data from a low altitude satellite with an orbit that passes through both the stable trapping region and the drift loss cone (DLC) region. Electrons in the DLC are quasi-trapped because azimuthal drift leads to their precipitation into the atmosphere within a drift period. Therefore the relative intensity levels in the two regions provide a measure of the loss rate. The time dependence of the stably trapped component combined with the loss rate then leads to an estimate of the required source rate. A single satellite cannot provide full spatial and temporal coverage and it is necessary to combine the data with a numerical model of the electron dynamics to obtain accurate results. In the model the precipitation losses are replenished by pitch angle diffusion while the source mechanism is unspecified and may include a combination of radial diffusion and local acceleration. Adiabatic effects are treated separately. Specific storm periods provide examples of the varying source and loss rates estimated with this method.
DE: 2716 Energetic particles: precipitating
DE: 2720 Energetic particles: trapped
DE: 2753 Numerical modeling
DE: 2774 Radiation belts
DE: 2788 Magnetic storms and substorms (7954)
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005