HR: 0800h
AN: SM41A-1118    [Abstracts]
TI: Effects of magnetic field asymmetry and compressional magnetic perturbations on radial diffusion of radiation belt electrons
AU: * Fei, Y
EM: yfei@rice.edu
AF: Rice University, MS-108, Rice University, 6100 Main St, Houston, TX 77005 United States
AU: Chan, A A
EM: aac@rice.edu
AF: Rice University, MS-108, Rice University, 6100 Main St, Houston, TX 77005 United States
AU: Elkington, S R
EM: scot.elkington@lasp.colorado.edu
AF: LASP, University of Colorado, LASP, University of Colorado 1234 Innovation Drive, Boulder, CO 80303 United States
AB: The radial diffusion coefficient of particles in a symmetric magnetic field perturbed by fluctuating electric fields is well known to depend on the power spectral density of the electric field at frequencies $\omega = m \omega_d$ (where $m$ is the azimuthal mode number, $\omega_d$ is the particle drift frequency) with an $L^6$ factor. In this work we have derived a radial diffusion coefficient for particles in an asymmetric magnetic field. The asymmetric diffusion coefficient depends on electric field power at resonance frequencies $\omega = (m \pm 1) \omega_d$ with $L^{12}$ dependence multiplying the power spectral density. Numerical diffusion rates obtained using test-particle simulations in model fields agree well with the analytical diffusion coefficients. Solutions of the radial diffusion equation for the September 1998 storm event are compared to an MHD-particle simulation. Earlier calculations used only electric-field diffusion coefficients, which had to be increased by a factor of 2 to 3 to get the best match with the MHD-particle results. New results will be presented of a radial diffusion calculation with compressional ULF waves added.
DE: 2149 MHD waves and turbulence
DE: 2471 Plasma waves and instabilities
DE: 2483 Wave/particle interactions
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting