Control, detection and mitigation of disruptions on ITER

Abstract

The fast loss of thermal and magnetic energy during an unmitigated disruption in ITER can lead to heat fluxes exceeding melt thresholds for plasma facing components, can generate high electromagnetic loads in some cases close to the design limits, and can potentially cause the generation of high energy runaway electrons. Therefore, the operation strategy in ITER will have a strong focus on limiting the number of disruptions and especially of those that are unmitigated. This will be achieved by a multi-layer strategy including disruption prevention and avoidance, disruption prediction and disruption mitigation. The plasma control system (PCS) will be in charge to react to any deviation from the predicted behavior by applying appropriate correction measures for which an extensive suite of actuators is available including those for active disruption prevention like electron cyclotron heating. It is also the PCS that optimizes triggering of the disruption mitigation system (DMS), should a disruption be imminent despite all control efforts. This paper will give an overview on all aspects of disruption control with a more detailed discussion of the requirements for the DMS.