HR: 1340h
AN: SM53B-1287    [Abstracts]
TI: Simulation of auroral electron acceleration by inertial Alfven waves
AU: * Swift, D W
EM: swift@gi.alaska.edu
AF: Geophysical Institute University of Alaska Fairbanks, 903 Koyukuk Drive PO Box 757320, Fairbanks, AK 99775-7320, United States
AB: A two-dimensional particle code, is used to model the acceleration of auroral electrons by inertial Alfven waves. The simulation domain is 20,000 km parallel to the magnetic field and some tens of kilometers across. Effects of a variable magnetic field and magnetic mirror force are included. The Alfven wave is launched by a moving bipolar potential wave-form with peak amplitudes of ±200V imposed at the top of the simulation domain. Electrons are accelerated to 3keV energy. Two types of acceleration processes are seen: one is impulsive acceleration from nonlinear shock structures that form and the other is from weaker parallel electric fields extending over several thousand kilometers. The shock structures are very small, and electrons accelerated by these structures can produce auroral forms with thicknesses considerably smaller than an electron inertial length. Electrons also tend to undergo multiple acceleration events. The code shows that electrons are more strongly accelerated upward. Half of these are destined to precipitate in the opposite hemisphere and half are destined to become trapped. This implies that much of the aurora seen in the northern hemisphere is due to electrons accelerated in the southern hemisphere. The simulations also suggest that auroral acceleration processes provide a likely source for radiation belt particles.
DE: 2704 Auroral phenomena (2407)
DE: 2716 Energetic particles: precipitating
DE: 2720 Energetic particles: trapped
DE: 2753 Numerical modeling
DE: 2774 Radiation belts
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting