Turbulence and Particle Acceleration in Collisionless Magnetic Reconnection: Effects of Temperature Inhomogeneity across Pre-reconnection Current Sheet

Abstract

Magnetic reconnection is an important process in various collisionless plasma environments because it reconfigures the magnetic field and releases magnetic energy to accelerate charged particles. Its dynamics depend critically on the properties of the pre-reconnection current sheet. One property in particular, cross-sheet temperature inhomogeneity, which is ubiquitous throughout the heliosphere, has been shown to increase reconnection outflow speed, energy conversion efficiency, and secondary island formation rate using two-dimensional particle-in-cell simulations. Here we expand upon these findings, considering two cases with a long, thin current sheet, one with homogeneous temperature and one with inhomogeneous temperature across the current sheet. In the inhomogeneous temperature case, numerous secondary islands form continuously, which increases current sheet turbulence (well-developed cascade power spectra) at large wavenumbers. Current density, energy conversion, dissipation, and acceleration of high-energy particles are also enhanced relative to the homogenous temperature case. Our results suggest that inhomogeneous temperature profiles, which are realistic, need to be incorporated into studies of turbulence and particle acceleration in collisionless magnetic reconnection.