Exact Vlasov-Maxwell equilibria for asymmetric current sheets

TL;DR

This paper introduces new exact equilibrium solutions for the Vlasov-Maxwell system, modeling asymmetric current sheets with more flexibility than previous solutions, relevant for understanding magnetic reconnection in space plasmas.

Contribution

It provides the first exact Vlasov-Maxwell equilibrium solutions for asymmetric current sheets with a guide field, enhancing modeling accuracy for magnetic reconnection.

Findings

New exact equilibrium solutions for asymmetric current sheets.

Distribution functions are composed of four shifted Maxwellians.

Equilibrium allows more magnetic field configurations than previous models.

Abstract

The NASA Magnetospheric Multiscale mission has made in situ diffusion region and kinetic-scale resolution measurements of asymmetric magnetic reconnection for the first time, in the Earth's magnetopause. The principal theoretical tool currently used to model collisionless asymmetric reconnection is particle-in-cell simulations. Many particle-in-cell simulations of asymmetric collisionless reconnection start from an asymmetric Harris-type magnetic field but with distribution functions that are not exact equilibrium solutions of the Vlasov equation. We present new and exact equilibrium solutions of the Vlasov-Maxwell system that are self-consistent with one-dimensional asymmetric current sheets, with an asymmetric Harris-type magnetic field profile, plus a constant nonzero guide field. The distribution functions can be represented as a combination of four shifted Maxwellian distribution functions. This equilibrium describes a magnetic field configuration with more freedom than the previously known exact solution and has different bulk flow properties.