KINK MODES AND CURRENT SHEETS IN CORONAL LOOPS

Abstract

We present simulations of the non-linear evolution of the m=1 kink mode in line-tied coronal loops. We focus on the structure of the current concentrations which develop as a consequence of the instability in two different types of magnetic field configuration, one containing a net axial current and the other with a vanishing total axial current. In the first case, current sheets develop one third of the way from footpoint to loop apex (where the non-linear kink mode folds on itself) within the body of the current channel, while in the second case the current sheet develops at the loop apex at the interface between the current containing channel and the outer axial potential field. In both cases line-tying, while playing a stabilizing role in the linear theory, acts as a destabilizing agent for the non-linear resistive evolution. The unwrapping of magnetic field lines in the vanishing axial current model appears to be consistent with the geometry of compact recurrent loop flares.