KINK MODES AND CURRENT SHEETS IN CORONAL LOOPS

We present simulations of the non-linear evolution of the m = 1 kink m ode in line-tied coronal loops. We focus on the structure of the curre nt 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. Tn the first case, current sheets develop one third of the way from f ootpoint 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 c urrent containing channel and the outer axial potential field. In both cases line-tying, while playing a stabilizing role in the linear theo ry, acts as a destabilizing agent for the non-linear resistive evoluti on. The unwrapping of magnetic field lines in the vanishing axial curr ent model appears to be consistent with the geometry of compact recurr ent loop flares.