HR: 16:30h
AN: SM14B-03    [Abstracts]
TI: Refilling of the Slot Region Between the Inner and Outer Electron Radiation Belts During Storms
AU: * Thorne, R M
EM: rmt@atmos.ucla.edu
AF: UCLA, Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA 90095, United States
AU: Shprits, Y Y
EM: yshprits@atmos.ucla.edu
AF: UCLA, Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA 90095, United States
AU: Meredith, N P
EM: nmer@bas.ac.ek
AF: British Antarctic Survey, Madingly Road, Cambridge, CB30ET, United Kingdom
AU: Horne, R B
EM: r.horne@bas.ac.uk
AF: British Antarctic Survey, Madingly Road, Cambridge, CB30ET, United Kingdom
AU: Li, W
EM: moonli@atmos.ucla.edu
AF: UCLA, Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA 90095, United States
AB: Energetic electrons (>50 keV) are injected into the slot region (2 < L < 4) between the inner and outer radiation belts during the early recovery phase of geomagnetic storms. Enhanced convection from the plasma sheet can account for the storm-time injection at lower energies, but does not explain the rapid appearance of higher energy electrons (> 150 keV). The effectiveness of either radial diffusion (driven by enhanced ULF waves) or local acceleration (during interactions with enhanced whistler-mode chorus emissions), as a potential source for refilling the slot at higher energies, is analyzed for observed conditions during the early recovery phase of the October 10, 1990 storm. We demonstrate that local acceleration, driven by observed chorus emissions, can account for the rapid enhancement in 200-700 keV electrons in the outer slot region near L = 3.3. Radial diffusion is much less effective, but may partially contribute to the flux enhancement at lower L. Subsequent outward expansion of the plasmapause during the storm recovery phase effectively terminates local wave acceleration in the slot, and prevents acceleration to energies higher than 700 keV. A statistical analysis of energetic electron flux enhancements and wave and plasma properties over the entire CRRES mission supports the concept of local wave acceleration as a dominant process for refilling the slot during the main and early recovery phase of storms. For moderate storms, the injection process naturally becomes less effective at energies greater than 1 MeV, due to the longer wave acceleration times and additional precipitation loss from scattering by EMIC waves. However, during extreme events when the plasmapause remains compressed for several days, conditions may occur to allow wave acceleration to multi-MeV energies at locations normally associated with the slot.
DE: 2720 Energetic particles: trapped
DE: 2730 Magnetosphere: inner
DE: 2772 Plasma waves and instabilities (2471)
DE: 2774 Radiation belts
DE: 2788 Magnetic storms and substorms (7954)
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting