Computer simulations on the spontaneous fast reconnection evolution in three dimensions

The dynamics of large-scale magnetic loop in three dimensions is studied by MHD simulations. The spontaneous fast reconnection model is used in this study. In this model, the fast reconnection evolves by the positive feedback between microscopic anomalous resistivities and macroscopic reconnection flows. It is demonstrated that even in the general three-dimensional situation, once a current-driven anomalous resistivity is ignited in a local region in the current sheet, the fast reconnection mechanism spontaneously evolves explosively by such positive feedback. It is remarkable that a fast shock builds up ahead of the magnetic loop in a very limited extent, since the three dimension fast reconnection jet strongly converges toward the magnetic loop top as in the two-dimension case.