Force-Free Equilibria, Solar Flares and Coronal Transients

Abstract

The solar flare phenomenon is due to the sudden dissipation of magnetic energy in the solar corona. Growing evidence shows that flares may occur in closed magnetic configurations, and that photospheric shearing motions are essential in triggering the phenomenon. This prompted several authors (Lew, 1977; Jockers, 1977; Birn and Schindler, 1978, the present authors), to study the properties of magnetic configurations able to exist in the solar corona. Flares often occur in long “arcades of loops”, and this suggests as a first step a simplification of the problem by considering 2-dimensional structures