Hall magnetohydrodynamics model of double discontinuities

Abstract

A double discontinuity is a compound structure composed of a slow shock layer and an adjoining rotational discontinuity layer on the postshock side. Since the Hall current effects become important as the magnetic field rotates by tens of degree over a thin rotational layer, steady state solutions based on the Hall magnetohydrodynamics (MHD) theory can show the merging of a rotational layer and a slow shock layer to form the observed compound structure. This model uses a set of modified Rankine–Hugoniot relations to calculate the jump conditions between the upstream region and the interface between the two layers, and uses the Hall-MHD equations to calculate the variations of the plasma and magnetic field in the rotational layer in the downstream of the interface. Four series of solutions are presented to show the effect for each of four governing parameters on the structure of double discontinuities.