Photospheric Shear Research Articles

Force-free magnetic arcades relevant to two-ribbon solar flares

Simple analytic models for the passive evolution of arcade-like magnetic fields through a series of force-free equilibria are presented. At the photospheric boundary, the normal magnetic field component is prescribed together with either the longitudinal field component or the photospheric shear. Analytic progress is made by considering either cylindrically symmetric solutions or using the separation of variables technique.

Force-Free Equilibria, Solar Flares and Coronal Transients

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