Effect of photospheric twisting motions on a confined toroidal loop

In this paper we investigate the effect of twisting motions at the photosphere on a curved loop confined by overlying field lines. We find that the twisting motions form a twisted loop along which a current builds up. However, the toroidal curvature of the loop appears to have a stabilising effect as there is no sign of the kink instability for a twist of 3.4 pi whereas in a straight cylinder for the same twist profile the critical twist is approximately 2.5 pi. When we include resistivity in the simulation there are indications that reconnection occurs and releases a substantial proportion of the free magnetic energy.