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P: Fachverband Plasmaphysik
P 17: Poster Session II
P 17.6: Poster
Mittwoch, 2. April 2025, 16:15–18:15, ZHG Foyer 1. OG
Plasma termination studies in LHD and W7-X — •Hjördis Bouvain1, Andreas Dinklage1, Naoki Tamura1, Hiroe Igami2, Hiroshi Kasahara2, Kieran McCarthy3, Daniel Medina-Roque3, Wendelstein 7-X Team1, and LHD Experiment Team2 — 1Max Planck Institute for Plasma Physics, Greifswald, Germany — 2National Institute for Fusion Science, Toki, Japan — 3Laboratorio Nacional de Fusion, CIEMAT, Madrid, Spain
Control of potentially occurring plasma terminating events is crucial for safe operation of large fusion devices. In tokamaks, disruptions, caused by current driven instabilities, lead to rapid loss of stored kinetic and magnetic energy. Stellarators, however, are more resilient since the poloidal field is generated from external coils, avoiding the loss of magnetic energy. Thermal quenches, due to large impurity influxes, are barely investigated in stellarators. These can cause significant damage to the wall material if the heat loads exceed a critical threshold, making the development of mitigation measures necessary. Intentional injection of large amounts of tungsten impurities via TESPEL in LHD and W7-X plasmas to study thermal quenches in more detail are investigated. Radiative losses along propagating cold fronts may induce termination, but below a critical threshold of impurity amounts the plasma may recover to stored energies prior perturbation. Application of additional electron heating extended the plasma cooling phase; thus, different heating strategies were explored. Results suggest that, in stellarators, less efforts for mitigating termination events are needed due to their higher operational resilience.
Keywords: tungsten; TESPEL; plasma termination; Wendelstein 7-X; LHD