Particle‐in‐cell simulations of three‐dimensional collisionless magnetic reconnection

Abstract

Three‐dimensional simulations of collisionless magnetic reconnection in a current sheet configuration are presented. The study consists of two parts: a simulation of a current sheet with an initial perturbation and another model run without it. Particular emphasis is on the questions (1) whether magnetic reconnection remains two‐dimensional if it initiates so, and (2) whether reconnection favors a patchy, localized mode over long, extended reconnection regions. Our study suggests that results from 2.5‐dimensional models of reconnection are not substantially altered by including variations in the third dimension. In fact, an initially random patchy reconnection structure appear to self‐organize into a more coherent quasi‐two‐dimensional structure. As in 2.5‐dimensional reconnection studies, the dominant contribution to the dissipation stems from off‐diagonal terms of the electron pressure tensor in our simulations. The dominant term is related to oscillatory electron motions between the regions of newly reconnected magnetic field.