Axisymmetric predictions for mitigated and vertically unstable disruptions in ITER with runaway electrons

TL;DR

This paper uses 2D simulations to study how ITER disruptions, including runaway electrons and vertical instabilities, can be mitigated through material injections and plasma control strategies.

Contribution

It introduces detailed simulation scenarios of ITER disruptions considering runaway electrons and vertical displacements, providing insights into mitigation techniques.

Findings

Runaway electron formation is significantly affected by injection timing.

Vertical displacement impacts runaway electron dynamics.

Mitigation strategies can potentially reduce runaway electron risks.

Abstract

We present two-dimensional global simulations of mitigated and vertically unstable disruptions in ITER in the presence of runaway electrons. An elongated plasma in free-boundary equilibrium is subjected to an artificial thermal quench and current-profile flattening, followed by one or more massive material injections and RE avalanche. Scenarios of major disruptions as well as upward and downward vertical displacement events are considered. Results provide important insights into the effects of runaway electron formation, post thermal quench current-profile, injection quantities and timings, and impurity flushout on the overall evolution of disruption and the plasma vertical motion thereof. Interplay between the various effects offers scope for potentially beneficial runaway electron mitigation scenarios.