Improved theory of forced magnetic reconnection due to boundary perturbation

Abstract

Boundary layer theory of forced magnetic reconnection due to an externally applied boundary perturbation is improved by introducing correct asymptotic matching which takes into account the effect of inertia in the inner layer precisely. The improved theory yields an integral equation for the time evolution of the reconnected flux. The initial evolution of the reconnection process is characterized by some significant features represented by the reconnected flux and an inner-layer reconnected flux. The typical time scales of the reconnected flux and of the inner-layer reconnected flux include the time scale of the boundary perturbation and exclude the Sweet-Parker time scale. The role of stability against the tearing modes in the reconnection process is also clarified. A current sheet induced on a resonant surface is in such a direction as to oppose the progress of the reconnection, because the equilibrium is stable against tearing modes in the absence of the boundary perturbation. Copyright © The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences.