SMuK 2023 – scientific programme

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P: Fachverband Plasmaphysik

P 6: Magnetic Confinement II/HEPP III

P 6.3: Talk

Tuesday, March 21, 2023, 11:55–12:20, CHE/0091

Linear MHD stability studies of pedestals in magnetically perturbed Tokamak plasmas — •Jonas Puchmayr, Mike Dunne, Erika Strumberger, Hartmut Zohm, and Matthias Willensdorfer — Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching, Germany

In H-mode Tokamak plasmas, edge localized modes (ELMs) limit the achievable pressure-gradient in the edge region and may cause severe damage in future fusion devices. For this reason, it is important to understand the onset conditions of ELMs and develop methods to avoid them. The ELM onset is well-described by the theory of peeling-ballooning (PB) modes which are magnetohydrodynamic (MHD) instabilities at the edge. This provides a framework to analyze the operational space of ELMs and their mitigation/suppression.

One method to suppress/mitigate ELMs is the application of magnetic perturbation (MP) fields. However, the impact of MPs on MHD stability is not well understood. In this talk, we use the CASTOR3D code for the numerical stability analysis of a range of plasmas. Results on the toroidal localization of PB modes in magnetically perturbed Tokamak plasmas are shown and successfully compared to experimental observations. We show that PB modes are predicted to appear only at selected toroidal locations when MP fields are applied and two different kinds of localization are distinguished. Finally, results on the effect of the MP fields on the linear MHD stability limit, i.e. the marginally stable edge pressure, are presented. In general, MP fields lead to a reduction of the stability limit, as experimentally observed.