Greifswald 2024 – scientific programme
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P: Fachverband Plasmaphysik
P 13: Magnetic Confinement IV/HEPP IV
P 13.4: Talk
Wednesday, February 28, 2024, 12:05–12:20, ELP 6: HS 3
Pedestal destabilization by 3D magnetic perturbation fields in tokamaks — •Jonas Puchmayr1, Mike Dunne1, Erika Strumberger1, Matthias Willensdorfer1, Hartmut Zohm1, Florian Hindenlang1, and ASDEX Upgrade Team2 — 1Max Planck Institute for Plasma Physics, Garching, Germany — 2See U. Stroth et al 2022 Nucl. Fusion 62 042006
In H-mode tokamak plasmas, edge localized modes (ELMs) limit the achievable pressure gradient in the edge region and might cause severe damage in future fusion devices. Consequently, it is crucial to understand the onset of ELMs and methods to mitigate or suppress them. The onset of an ELM is typically well-described by the growth of magnetohydrodynamic instabilities at the plasma edge.
One method to mitigate or suppress ELMs is the application of magnetic perturbation (MP) fields. In this work, we use the linear extended MHD stability code CASTOR3D to show for the first time that symmetry-breaking by MP fields can significantly reduce the achievable stable pedestal pressure by up to 30%, resulting in mitigated ELMs. The destabilizing effect on the achievable stable pedestal pressure due to MP fields remains if ion diamagnetic drift effects, which strongly stabilize high-n ballooning modes, are included. The lowest pedestal top pressure resulting in the onset of MHD modes in 3D AUG plasmas has been found by interpolating between two equilibria featuring ELM mitigation and suppression, corresponding to the empirically observed pedestal pressure limit for complete ELM suppression.
Keywords: Magnetohydrodynamics; Edge Localized Modes; ELM suppression; Linear MHD