Evolution and statistics of current sheets in coronal magnetic loops

Abstract

A resistive magnetohydrodynamic model is proposed for a straightened coronal loop subject to continuous slow fluctuating random footpoint driving. The characteristic timescale of this driving motion is much longer than the Alfven transit time along the loop. The governing equations for this model are integrated numerically until a statistical steady state is attained. In steady state the spatial structure of the magnetic field is dominated by thin regions of intense current density indicative of current sheets. Using a simple model of resistive reconnection the statistical steady state can be understood as a random superposition of current sheets. This model predicts the scaling of the sheet parameters and the global heating with resistivity. The scaling is verified over the small range of values achievable in these numerical experiments.