Asymmetric kinetic equilibria: demonstration of the independence of magnetic reconnection signatures to the initial current sheet structure.

Abstract:

Current sheets are ubiquitous in space plasmas and yet hard to describe with a kinetic equilibrium. The BAS model is a semi-analytical model which provides a steady distribution function for asymmetric current sheet ions. In this paper, we prove that an ion kinetic equilibria produced by this model remain steady in a fully kinetic Particle-In-Cell simulation even if the electron distribution function is not an equilibrium. We then apply this equilibrium to look at the dependence of magnetic reconnection simulations upon their initial condition. We demonstrate that regardless of macroscopic or microscopic differences between initial current sheets, signatures of magnetic reconnection only depends on the upstream plasma. This demonstration is the first to confirm this widely use assumption and comforts the relevance of comparisons between simulations and observations in the electron decoupling region, such as in the context of the upcoming Magnetospheric Multiscale mission.