Fast reconnection in high temperature plasmas

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Abstract
Pressure forces acting on electrons are shown to dramatically alter magnetic field line reconnection in high temperature plasmas. The electron pressure introduces a new physical scale length ρs, the ion gyroradius based on the electron temperature, into the resistive magnetohydrodynamic (MHD) equations. The single dissipation layer of resistive MHD is split into two distinct layers by this effect: a very small inner current layer and a larger flow layer. Unlike resistive MHD, the current layer is microscopic in the outflow, as well as the inflow, direction. As a consequence, the current layer is not unstable to the formation of secondary magnetic islands at low values of resistivity and patchy reconnection does not occur. The absence of a strong current sheet in the outflow region enables the magnetic nozzle controlling the outflow to open up. The magnetic reconnection rate therefore remains large as the resistivity η and ρs become small.