Hybrid Modeling of the Formation of Thin Current Sheets in Magnetotail Configurations

Abstract

Hybrid simulations are used to investigate the formation of a thin current sheet inside the plasma sheet of a magnetotail-like configuration. The initial equilibrium is subjected to a driving electric field qualitatively similar to what would be expected from solar wind driving. As a result, we find the formation of a new current sheet, with a thickness of approximately the ion inertial length. The current density inside the current sheet region is supplied largely by the electrons. Ion acceleration in the cross-tail direction is absent due since the driving electric field fails to penetrate into the equatorial region. The ions in the thin current sheet region exhibit anisotropies which appear to be driven by the bounce motion in the z direction between the inward moving plasma sheet-lobe boundary.