HR: 1340h
AN: SM33A-0428    [Abstracts]
TI: First or second order Fermi acceleration of energetic particles in the radiation belt?
AU: * Zhang, M
EM: mzhang@fit.edu
AF: Florida Institute of Technology, Dept. of Physics and Space Science, 150 W. University Blvd., Melbourne, FL 32901 United States
AB: Energetic particle transport in the radiation belts has been traditionally described using canonical variables, which implicitly ignore, or at least show no relationship to, both the small-scale electric field that may drive particle diffusion and the large-scale electric field that drives mgnetospheric convection. Therefore, the usage of only canonical variables obscures the physics of particle acceleration because it is only the electric field that can cause charged particles to change energy. With a quasilinear method developed for cosmic ray studies, we have established a magnetospheric particle transport equation in the phase space of location and momentum. The new transport equation includes essentially all the basic particle transport mechanisms and it can become a theoretical foundation for developing future numerical models of particle transport in the magnetosphere. In this paper, we will concentrate on the discussion of particle acceleration mechanisms possibly happening in the magnetosphere. Using a model map of magnetospheric convection pattern, we have found that the compression of magnetospheric plasma can play important roles in particle acceleration and trapping, particularly during the storm time. The compressional particle acceleration is similar to the first-order Fermi acceleration that occurs at shock waves in other space plasma settings. This mechanism may possibly be the cause of the in-situ acceleration of relativistic electrons in the radiation belt. In addition, we will discuss the condition and possibility of second Fermi acceleration of particles during radial diffusion.
DE: 2720 Energetic particles: trapped
DE: 2774 Radiation belts
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005