HR: 11:35h
AN: SM12A-06    [Abstracts]
TI: Low-altitude Measurements of 2-6 MeV Electron Trapping Lifetimes at 1.5 < L < 2.5
AU: * Baker, D N
AF: University of Colorado - LASP, 1234 Innovation Drive, Boulder, CO 80303, United States
AU: Kanekal, S G
AF: University of Colorado - LASP, 1234 Innovation Drive, Boulder, CO 80303, United States
AU: Horne, R B
AF: British Antarctic Survey, Madingley Road, Cambridge, CB3 OET, United Kingdom
AU: Meredith, N P
AF: British Antarctic Survey, Madingley Road, Cambridge, CB3 OET, United Kingdom
AU: Glauert, S A
AF: British Antarctic Survey, Madingley Road, Cambridge, CB3 OET, United Kingdom
AB: During the Halloween Storm period (October-November 2003), the Van Allen belt electron population was powerfully accelerated and re-established inward of its normal position. The new inner belt of electrons formed in this process decayed over a period of days to years. We have examined quantitatively the decay rates for electrons seen in the region of 1.5 < L <2.5 using SAMPEX satellite observations. We find that at L=1.5 the e- folding lifetime for 2-6 MeV electrons was τ~ 180 days. On the other hand, for the half-dozen distinct acceleration (or enhancement) events seen during late-2003 through 2005 at L~ 2.0, the lifetimes ranged from τ~ 8 days to τ~ 35 days. We compare these loss rates to those expected from prior observational and theoretical studies. We find that these lifetimes at L=2.0 are much shorter than the average 100-200 days that present theoretical estimates would suggest for the overall L=2 electron population. Additional wave-particle interaction aspects must be included in theoretical treatments. We describe such possibilities in this talk based on careful new analysis of particle scattering lifetimes at low L-values.
DE: 2483 Wave/particle interactions (7867)
DE: 2716 Energetic particles: precipitating
DE: 2730 Magnetosphere: inner
DE: 2736 Magnetosphere/ionosphere interactions (2431)
DE: 2768 Plasmasphere
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting