Fast collisionless reconnection and electron heating in strongly magnetized plasmas

Abstract

Magnetic reconnection in strongly magnetized (low-beta), weakly collisional plasmas is investigated using a novel fluid-kinetic model [Zocco & Schekochihin, Phys. Plasmas 18, 102309 (2011)] which retains non-isothermal electron kinetics. It is shown that electron heating via Landau damping (linear phase mixing) is the dominant dissipation mechanism. In time, electron heating occurs after the peak of the reconnection rate; in space, it is concentrated along the separatrices of the magnetic island. For sufficiently large systems, the peak reconnection rate is $cE_{max}\approx 0.2v_AB_{y,0}$, where $v_A$ is the Alfv\'en speed based on the reconnecting field $B_{y,0}$. The island saturation width is the same as in MHD models except for small systems, when it becomes comparable to the kinetic scales.