Multi-scale/multi-fluid simulations of the post plasmoid current sheet in the terrestrial magnetosphere

Abstract

Multi-scale/multi-fluid simulations are used to provide the first high resolution (∼120 km) simulations of a thin tail current sheet within the global framework of the Earth's magnetosphere during southward IMF. The current sheet in the tail is shown to thin to 1200 km in the wake of a plasmoid. A hydrogen boundary layer forms on the outside of the current sheet with a thickness on the order of 900 km. Kinks form in the cross-tail direction in the thin current sheet with a wavelength on the order of 1 RE. The amplitude grows up to 0.5 RE before the kinks become unstable, leading to the reformation of a thicker current sheet. These kinks initiate just earthward of the reconnection region and propagate both tailward, and earthward until they reach dipolar fieldlines. These processes occur as the result of the coupling between cross-tail flows in O+ and field-aligned flows in ionospheric H+. Copyright 2006 by the American Geophysical Union.