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P: Fachverband Plasmaphysik

P 19: Poster II

P 19.5: Poster

Thursday, March 31, 2022, 16:00–17:30, P

Predictive simulations of Runaway Electron deconfinement by a helical coil — •Nina Schwarz, Javier Artola, Konsta Särkimäki, and Matthias Hölzl — Max Planck Institute for Plasma Physics, Boltzmannstrasse 2, 85748 Garching - Germany

Future tokamak fusion power plants are designed as high plasma current devices which comes with the risk of generating fast electrons during disruptions. Due to an avalanche mechanism a small seed can create so called Runaway Electrons (RE), which can carry more than 50% of the plasma current. The surrounding structures can be damaged seriously when the vertically unstable RE beam comes into contact with the wall. Current avoidance or mitigation concepts are based on active techniques like the injection of deuterium for plasma dilution. A passive mitigation system has been proposed consisting of a passive coil, in which current is induced during a current quench (CQ), that in turn generates a helical perturbation in the plasma. This triggers magnetic islands that grow and overlap and thus create a region of enhanced radial transport. When a large part of the plasma is stochastic, the complete formation of an RE beam can be mitigated or even be fully prevented. We show here a possible coil geometry based on the SPARC concept [1] in the ASDEX Upgrade configuration. The induction efficiency of the coil is investigated for different CQ times and the vacuum perturbation by different geometries are shown. Finally, 3D non-linear simulations of a disruption with the extended MHD code JOREK are presented with a fully self-consistent inclusion of the passive coil. [1] R.A. Tinguely et al 2021 Nucl. Fusion 61 124003