HR: 0800h
AN: NG21B-0522    [Abstracts]
TI: Chaotic Magnetic Fields due to Asymmetric Current Configurations - Modeling Cross-Field Diffusion of Charged Particles in Cosmic Rays
AU: * Ram, A K
EM: abhay@mit.edu
AF: Plasma Science and Fusion Center, Massachusetts Institute of Technology, Room NW16- 260, 77 Massachusetts Avenue, Cambridge, MA 02139-4307, United States
AU: Dasgupta, B
EM: dasgupta@ucr.edu
AF: Institute of Geophysics and Planetary Physics, University of California at Riverside, 900 University Avenue, Riverside, CA 92521, United States
AB: The observed cross-field diffusion of charged particles in cosmic ray transport is assumed to be due to chaotic nature of the interplanetary/intergalactic magnetic fields. The particles are accelerated and energized by the temporal fluctuations of the magnetic field. The generation of chaotic magnetic fields is ad hoc and the characteristics of the fields are chosen to satisfy the observations. We consider simple current configurations consisting of circular loops and straight wires that generate asymmetric, nonlinear, steady-state magnetic fields in three spatial dimensions. These magnetic fields are completely deterministic, and, for certain range of parameters, chaotic. We will present analytical and numerical studies on the generation of chaotic magnetic fields and the nature of these fields. The motion of charged particles in the nonlinear and in the chaotic magnetic fields can be described by the Lorentz equation. An analysis of the particle motion will be presented. A particle moving in chaotic magnetic field superposed on a uniform background magnetic field is found to undergo spatial transport. This shows that chaotic magnetic fields can produce cross-field diffusion. This work is supported by DoE Grant DE-FG02-91ER-54109.
DE: 2104 Cosmic rays
DE: 2134 Interplanetary magnetic fields
DE: 4420 Chaos (7805)
DE: 7807 Charged particle motion and acceleration
DE: 7839 Nonlinear phenomena (4400, 6944)
SC: Nonlinear Geophysics [NG]
MN: 2007 Fall Meeting