HR: 1340h
AN: SM13A-1120    [Abstracts]
TI: Self Consistent Calculation of Fokker-Planck Coefficients for Transport in Space Plasmas
AU: * Presicci, M
AF: Laboratory for Atmospheric and Space Physics, University of Colorado, 1234 Innovation Drive, Boulder, CO 80303, United States
AU: Baker, D N
AF: Laboratory for Atmospheric and Space Physics, University of Colorado, 1234 Innovation Drive, Boulder, CO 80303, United States
AU: Gehmeyr, M
AF: Laboratory for Atmospheric and Space Physics, University of Colorado, 1234 Innovation Drive, Boulder, CO 80303, United States
AB: Most space plasmas present velocity distributions with superthermal tails, fitted with kappa distributions. Some investigators have demonstrated a kappa distribution solution to the Fokker-Planck equation containing a longitudinal diffusion coefficient with an added (velocity)^-1 dependence. These calculations rely on transport coefficients evaluated with an underlying equilibrium (Maxwellian) distribution, although the steady state solution remains kappa and never attains full equilibrium. This investigation presents the functional form for transport coefficients calculated self-consistently with an underlying kappa distribution rather than a Maxwellian distribution. These transport coefficients, retain the same velocity dependence in the high velocity (asymptotic) limit, so that (velocity)^-1 dependence to the diffusion coefficient, that these earlier investigators seek is revalidated. However, below this limit, the functional form of the transport coefficients calculated self-consistently differs from these coefficients used in earlier solutions to the steady state Fokker-Planck equation. Relaxation times for plasma transport based on these revised functional forms will be calculated and compared with earlier calculated relaxation times. Implication to space weather modeling will be presented.
DE: 7807 Charged particle motion and acceleration
DE: 7857 Stochastic phenomena (3235, 3265, 4475)
DE: 7859 Transport processes
DE: 7863 Turbulence (4490)
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting