HR: 08:45h
AN: SM31A-02 INVITED     [Abstracts]
TI: How the Plasmapause Affects Relativistic Electron Variability in the Outer Radiation Belt
AU: * Thorne, R M
EM: rmt@atmos.ucla.edu
AF: UCLA, Department of Atmospheric and Oceanic Sciences, 7127MS, Box 951565, Los Angeles, CA 90095-1565 United States
AB: Variability of energetic electrons in the outer radiation belt is due to an imbalance between source and loss processes. Source processes include radial diffusion (driven by enhanced ULF waves) and local stochastic acceleration by VLF plasma waves, while losses are primarily due to wave-particle scattering and ultimate loss to the atmosphere. At the onset of a magnetic storm, despite a pronounced increase in the source of acceleration, losses usually dominate causing a net depletion of relativistic outer zone flux. Flux increases can occur during the storm recovery, when losses become less pronounced. The plasmapause location plays a fundamental role in controlling the effectiveness of the source and loss processes. Enhanced ULF waves and VLF chorus emissions are primarily excited outside the plasmapause during disturbed conditions. Both waves contribute to the acceleration source. Intense EMIC waves, excited along the dusk-side plasmapause (and plume) can provide an effective scattering loss for relativistic electrons, especially during the main phase of a storm as ring current protons are injected into the system. Recent theoretical simulations of the effectiveness of potential source and loss processes will be presented, and related to the location of the disturbed plasmapause location.
DE: 2716 Energetic particles, precipitating
DE: 2720 Energetic particles, trapped
DE: 2730 Magnetosphere--inner
DE: 2768 Plasmasphere
DE: 2772 Plasma waves and instabilities
SC: SPA-Magnetospheric Physics [SM]
MN: 2005 Joint Assembly