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P: Fachverband Plasmaphysik
P 9: Poster I
P 9.29: Poster
Tuesday, March 29, 2022, 16:00–17:30, P
Linear (non-)ideal MHD stability analysis of pedestals in axisymmetric tokamak equilibria — •Jonas Puchmayr1, Mike Dunne1, Erika Strumberger1, Branka Vanovac1, Hartmut Zohm1, and The ASDEX Upgrade Team2 — 1Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching, Germany — 2See author list of H. Meyer et al. 2019 Nucl. Fusion 59 112014
In the H-mode, steep gradients of pressure, temperature and density build up at the plasma edge. These gradients can drive a type of instability, called Edge Localized Modes (ELMs). ELMs will lead to severe damage in future fusion devices. While ELMs are typically well-described as a pressure gradient and current density driven instability in the framework of ideal MHD, there are experimentally observed instabilities that can only be described including additional non-ideal effects in the stability calculation. Experimentally, ELMs are observed to be mitigated or suppressed by resonant magnetic perturbation (RMP) fields, which break the axisymmetry of tokamak equilibria.
In this work, the influence of non-ideal effects on linear MHD stability is analyzed using the code CASTOR3D. As a result, the experimentally observed mode frequency is in good agreement with the theoretical prediction only if resistivity, rotation, viscosity and gyro-viscosity are simultaneously taken into account. In addition, we observe a strong influence of resistivity on the MHD stability threshold for several equilibria. Finally, new results on weakly toroidally coupled modes in magnetically perturbed tokamak equilibria are presented.