HR: 0830h
AN: SH21B-0149    [PDF]
TI: Test Particle Acceleration by Turbulent MHD Fields on Alfvenic Timescales
AU: * Dmitruk, P
EM: pablo@bartol.udel.edu
AF: Bartol Research Institute University of Delaware, 217 Sharp Lab, Newark, DE 19716 United States
AU: Matthaeus, W H
EM: whm@udel.edu
AF: Bartol Research Institute University of Delaware, 217 Sharp Lab, Newark, DE 19716 United States
AU: Seenu, N
EM: nirmal@udel.edu
AF: Bartol Research Institute University of Delaware, 217 Sharp Lab, Newark, DE 19716 United States
AU: Brown, M R
EM: doc@swarthmore.edu
AF: Department of Physics Swarthmore College, 500 College Avenue, Swarthmore, PA 19081 United States
AB: We study the short time acceleration of charged particles in turbulent fields obtained from direct numerical solutions of the compressible 3D MHD equations. Different test particle simulations are performed, varying the ratio between the typical turbulent timescale and the nominal gyroperiod of the particles. Starting from monoenergetic particles moving at the characteristic plasma Alfven speed, we find consistent acceleration to high energies in times of the order of the turbulent timescale. Extended power laws in the distribution of particle energies are obtained, with different slopes at intermediate and high energies. Linear scaling laws of the maximum and mean energy of the particles with the turbulent time / nominal gyroperiod ratio are observed and mechanisms based on reconnecting fields are proposed to explain them.
DE: 2149 MHD waves and turbulence
DE: 7514 Energetic particles (2114)
DE: 7807 Charged particle motion and acceleration
DE: 7835 Magnetic reconnection
DE: 7843 Numerical simulation studies
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting