Sausage to kink instability transition-induced fast magnetic reconnection resulting in plasma jet eruption
Abstract
Solar transient phenomena, such as flares and eruptions, are believed to be caused by fast magnetic reconnection. Magnetized solar plasmas are susceptible to the same ideal MHD instabilities as are observed in experiments. MHD theory well characterizes the dynamics of large-scale magnetized plasma but fails to explain fast reconnection that happens when the length scale approaches the ion skin depth. This work proposes a model for the transition from MHD to kinetic scale such that a sequence of MHD instabilities ultimately lead to fast non-MHD magnetic reconnection. We observed in the Caltech laboratory plasma jet a distinct sequence of MHD instabilities going from sausage to kink. This sequence resulted in a thinning of the current channel which led to the plasma erupting. The mechanism allows macro-scale length plasma to access the micro-scale at which Hall physics becomes important. Whistler waves, high energy X-rays, and current/voltage spikes were observed simultaneously with the eruption event. A 3D ideal MHD numerical simulation reproduces the MHD instability sequence and demonstrates the location/time at which Hall physics becomes significant. The experiment and the numerical results agree with the MHD energy principle analytic stability conditions of a current-carrying magnetic flux tube.
- Publication:
-
Solar Heliospheric and INterplanetary Environment (SHINE 2019)
- Pub Date:
- May 2019
- Bibcode:
- 2019shin.confE..56W