HR: 10:50h
AN: SM51E-03    [PDF]
TI: Global flux isotropization and in-situ Pitch angle evolution during relativistic electron energization in the outer zone.
AU: * Kanekal, S G
EM: kanekal@surya.umd.edu
AF: Catholic University, Dept. of Physics, Washington, DC 20064 United States
AU: Friedel, R H
AF: Los Alamos National Laboratory, Space and Atmospheric Sciences, Los Alamos, NM 87545 United States
AU: Reeves, G D
AF: Los Alamos National Laboratory, Space and Atmospheric Sciences, Los Alamos, NM 87545 United States
AB: Energization of outer zone electrons to relativistic energies in the Earth's magnetosphere is fundamentally caused by high solar wind velocity and the southward turning of the interplanetary magnetic field. However, details of all the physical processes involved, are ill understood. Relativistic electron fluxes in the outer zone are highly dynamic and vary over several orders of magnitude on time scales of a few days. Energization models invoke processes ranging from radial diffusion to in-situ acceleration mechanisms. Important characteristics of electron energization such as electron pitch angle distribution and isotropization enable identification of separate energization mechanisms. We report on the measurements of in-situ pitch angle evolution at geosynchronous altitude and global isotropization of relativistic electrons during recent electron energization events.We use data from energetic particle sensors onboard SAMPEX and the recently developed pitch angle data from the SOPA and the ESP sensors onboard LANL spacecraft. The latter provide an in-situ view of the electron pitch angle distribution at geosynchronous altitudes. Comparison of electron fluxes measured by SAMPEX which is in low earth orbit, with LANL geosynchronous data provides a global view of the flux isotrpization time scales.
DE: 2716 Energetic particles, precipitating
DE: 2720 Energetic particles, trapped
DE: 2730 Magnetosphere--inner
DE: 2784 Solar wind/magnetosphere interactions
DE: 2788 Storms and substorms
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting