Thermal Quench in ITER Locked Mode Disruptions

TL;DR

This paper models the thermal quench process during ITER locked mode disruptions, highlighting how the high conductivity of the vacuum vessel may alter the disruption dynamics and potentially extend the precursor phase.

Contribution

It provides simulations and theoretical analysis of the thermal quench in ITER disruptions, emphasizing the impact of the vacuum vessel's conductivity on disruption evolution.

Findings

RWTM slows down in ITER due to high vacuum vessel conductivity

Thermal quench may have a longer timescale (~100ms) in ITER

Precursor phase could be prolonged without rapid termination

Abstract

Simulations and theory are presented of an ITER locked mode thermal quench (TQ). In present experiments, locked mode disruptions have a long precursor phase, followed by a rapid termination and thermal quench, which can be identified with a resistive wall tearing mode (RWTM). In ITER, the RWTM will be slowed by the highly conductive vacuum vessel. The rapid termination might be absent, and the plasma could remain in the precursor phase. If the edge temperature is in the collisional regime, the TQ would proceed on a long timescale, limited by the RWTM to almost $100ms.$ This is an important self mitigating effect.