One-Dimensional Asymmetric Current Sheets

Abstract

The NASA MMS mission has very recently made in situ diffusion region measurements of asymmetric magnetic reconnection for the first time (Burch et al. 2016). In order to compare to the data obtained from kinetic-scale observations (e.g. see Burch and Phan 2016), it would be useful to have initial equilibrium conditions for PIC simulations that reproduce the physics of the dayside magnetopause current sheet as accurately as possible, i.e. self-consistent VM equilibria that model the magnetosheath-magnetosphere asymmetries in pressure and magnetic field strength. In this chapter, we present new ‘exact numerical’ (numerical solutions to equations for exact VM equilibria), and exact analytical equilibrium solutions of the VM system that are self-consistent with 1D and asymmetric Harris-type current sheets, with a constant guide field. The DFs can be represented as a combination of shifted Maxwellian DFs, are consistent with a magnetic field configuration with more freedom than the previously known exact solution (Alpers 1969), and have different bulk flow properties far from the sheet.