HR: 1340h
AN: SM33C-0463    [Abstracts]
TI: The Role of Magnetic Reconnection in Producing Energetic Electrons
AU: * Pritchett, P L
EM: pritchet@physics.ucla.edu
AF: Department of Physics and Astronomy, University of California, 405 Hilgard Avenue, Los Angeles, CA 90095-1547 United States
AB: Magnetic reconnection is a widely occurring process (solar flares, magnetospheric substorms) that converts stored magnetic energy into kinetic energy of various forms. There is mounting evidence that a significant portion of this energy release occurs in the form of accelerated electrons with energy ~20--300 keV. 2D and 3D massively parallel PIC simulations are used to investigate this acceleration mechanism for the cases of anti-parallel and guide field reconnection. In both cases the fundamental process is found to be an inverse Landau damping that occurs right at the X line for electrons with v_x ≈ 0. These particles can stream across the current sheet and be accelerated by the inductive electric field. In the anti-parallel case electrons just away from the X line are kicked out by the -ev_yB_z/c force and spread out symmetrically along the separatrices. In contrast, for the guide field case where the electrons remain magnetized, electrons are accelerated in toward the X line by a parallel electric field in a low density region along one pair of separatrices. These electrons form a cold beam with speed of the order of the Alfvén speed based on the electron mass (energy ~5--10 keV). The main acceleration occurs at the X line where the density is much higher. The resulting stretched electron distribution emerges as a parallel-oriented feature along the other pair of separatrix arms. A characteristic feature of the reconnection acceleration mechanism is its unidirectional character, leading to a predicted strong dawn-dusk asymmetry in the energetic electrons in the magnetotail.
DE: 2723 Magnetic reconnection (7526, 7835)
DE: 2744 Magnetotail
DE: 7835 Magnetic reconnection (2723, 7526)
DE: 7845 Particle acceleration
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005