Spontaneous reconnection at a separator current layer: 2. Nature of the waves and flows

摘要

Sudden destabilizations of the magnetic field, such as those caused by spontaneous reconnection, will produce waves and/or flows. Here we investigate the nature of the plasma motions resulting from spontaneous reconnection at a 3-D separator. In order to clearly see these perturbations, we start from a magnetohydrostatic equilibrium containing two oppositely signed null points joined by a generic separator along which lies a twisted current layer. The nature of the magnetic reconnection initiated in this equilibrium as a result of an anomalous diffusivity is discussed in detail in Stevenson and Parnell (2015). The resulting sudden loss of force balance inevitably generates waves that propagate away from the diffusion region carrying the dissipated current. In their wake a twisting stagnation flow, in planes perpendicular to the separator, feeds flux back into the original diffusion site (the separator) in order to try to regain equilibrium. This flow drives a phase of slow weak impulsive bursty reconnection that follows on after the initial fast-reconnection phase.