Electron distribution functions in the diffusion region of asymmetric magnetic reconnection

Abstract

AbstractWe study electron distribution functions in a diffusion region of antiparallel asymmetric reconnection by means of particle‐in‐cell simulations and analytical theory. At the electron stagnation point, the electron distribution comprises a crescent‐shaped population and a core component. The crescent‐shaped distribution is due to electrons coming from the magnetosheath toward the stagnation point and accelerated mainly by electric field normal to the current sheet. Only a part of magnetosheath electrons can reach the stagnation point and form the crescent‐shaped distribution that has a boundary of a parabolic curve. The penetration length of magnetosheath electrons into the magnetosphere is derived. We expect that satellite observations can detect crescent‐shaped electron distributions during magnetopause reconnection.