Electron acceleration during guide field magnetic reconnection

Particle-in-cell simulations of the guide field intermittent magnetic reconnection are performed to study electron acceleration and pitch angle distributions. During the growing stage of reconnection, the power-law distribution function for the high-energy electrons and the pitch angle distributions of the low-energy electrons are obtained and compare favorably with observations by the Wind spacecraft. Direct evidence is found for the secondary acceleration during the later reconnection stage. A correlation between the generation of energetic electrons and the induced reconnection electric field is found. Energetic electrons are accelerated first around the X line, and then in the region outside the diffusion region, when the reconnection electric field has a bipolar structure. The physical mechanisms of these accelerations are discussed. The in-plane electrostatic field that traps the low-energy electrons and causes the anisotropic pitch angle distributions has been observed. (C) 2008 American Institute of Physics.