Complete 3D MHD simulations of the current quench phase of ITER mitigated disruptions

TL;DR

This paper presents comprehensive 3D MHD simulations of the current quench phase in ITER disruptions, revealing force magnitudes and dynamics crucial for understanding wall interactions during mitigated disruptions.

Contribution

First-time complete 3D simulations of ITER mitigated disruptions at realistic Lundquist numbers, providing insights into force magnitudes and timing during the current quench phase.

Findings

Edge safety factor remains above 2

Horizontal forces stay below 1 MN

Vertical force peaks at 13 MN after plasma decay

Abstract

Complete 3D simulations of the current quench phase of ITER disruptions are key to predict asymmetric forces acting into the ITER wall. We present for the first time such simulations for ITER mitigated disruptions at realistic Lundquist numbers. For these strongly mitigated disruptions, we find that the edge safety factor remains above 2 and the maximal integral horizontal forces remain below 1 MN. The maximal integral vertical force is found to be 13 MN and arises in a time scale given by the resistive wall time as expected from theoretical considerations. In this respect, the vertical force arises after the plasma current has completely decayed, showing the importance of continuing the simulations also in the absence of plasma current. We conclude that the horizontal wall force rotation is not a concern for these strongly mitigated disruptions in ITER, since when the wall forces form, there are no remaining sources of rotation.