Enhanced plasma current spike formation due to onset of 1/1 kink-tearing reconnection during a massive gas injection process

TL;DR

This paper investigates how the onset of 1/1 kink-tearing reconnection influences plasma current spike formation during massive gas injection, highlighting the role of MHD activity on the q=1 surface in disruption dynamics.

Contribution

It provides a systematic analysis linking plasma current spikes to kink-tearing reconnection onset and MHD activity during disruptions, supported by simulation results.

Findings

Plasma current spike correlates with 1/1 kink-tearing reconnection onset.

MHD activity on the q=1 surface influences disruption and spike formation.

Safety factor q0 > 1 delays thermal quench and causes successive minor disruptions.

Abstract

The formation of the plasma current spike at the end of the thermal quench phase is studied systematically, which is found to strongly correlate to the onset of the 1/1 kink-tearing reconnection in the simulation results. The magnetohydrodynamic (MHD) activity on the q = 1 surface plays a critical role in the spike formation and the disruption process, namely, when the safety factor in the magnetic axis q0 exceeds 1, the plasma major disruption transits into successive minor disruptions and the start of thermal quench phase is delayed.