Particle-in-cell simulation study of the scaling of asymmetric magnetic reconnection with in-plane flow shear

TL;DR

This study uses particle-in-cell simulations to analyze how asymmetric magnetic reconnection scales with in-plane flow shear, revealing conditions under which flow suppresses reconnection in space and laboratory plasmas.

Contribution

It provides new simulation-based insights into the scaling laws of asymmetric magnetic reconnection with flow shear, extending previous theoretical predictions.

Findings

Good agreement with theory below cutoff velocity

Flow shear can suppress reconnection

Applications to space and laboratory plasmas

Abstract

We investigate magnetic reconnection in systems simultaneously containing asymmetric (anti-parallel) magnetic fields, asymmetric plasma densities and temperatures, and arbitrary in-plane bulk flow of plasma in the upstream regions. Such configurations are common in the high-latitudes of Earth's magnetopause and in tokamaks. We investigate the convection speed of the X-line, the scaling of the reconnection rate, and the condition for which the flow suppresses reconnection as a function of upstream flow speeds. We use two-dimensional particle-in-cell simulations to capture the mixing of plasma in the outflow regions better than is possible in fluid modeling. We perform simulations with asymmetric magnetic fields, simulations with asymmetric densities, and simulations with magnetopause-like parameters where both are asymmetric. For flow speeds below the predicted cutoff velocity, we find good scaling agreement with the theory presented in Doss et al., J.~Geophys.~Res., 120, 7748 (2015). Applications to planetary magnetospheres, tokamaks, and the solar wind are discussed.