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

TL;DR

This paper investigates the plasma waves and flows generated by spontaneous magnetic reconnection at a 3D separator, revealing the complex wave-flow interactions and their role in flux redistribution post-reconnection.

Contribution

It provides a detailed analysis of the wave and flow dynamics resulting from spontaneous reconnection at a separator, highlighting the nature of plasma motions and flux feedback mechanisms.

Findings

Waves propagate away from the diffusion region carrying dissipated current.

A twisting stagnation-flow feeds flux back into the separator.

A phase of slow impulsive-bursty reconnection follows the initial fast phase.

Abstract

Sudden destabilisations 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 3D 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 \cite{Stevenson15_jgra}. 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.