Computer studies of a large-scale plasmoid driven by spontaneous fast reconnection

Abstract

The temporal dynamics of a plasmoid is studied by computer simulations. On the basis of the spontaneous fast reconnection model, it is demonstrated that a large-scale plasmoid is formed and propagates in a long current-sheet system. The fast reconnection develops and proceeds in a limited region of the system at large. At the edge of the fast reconnection region, a supersonic plasma jet erupts drastically, giving rise to a fast shock at the interface between the plasmoid and the fast reconnection regions. Accordingly, the plasma pressure is found to be notably enhanced in the plasmoid, which allows the plasmoid to swell and propagate effectively. It is argued that the supersonic plasma jet plays a dominant role in the formation and propagation of the large-scale plasmoid.