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P: Fachverband Plasmaphysik
P 6: Magnetic Confinement II/HEPP III
P 6.2: Vortrag
Dienstag, 21. März 2023, 11:30–11:55, CHE/0091
Gyrokinetic turbulence simulations in the pedestal — •Leonhard A. Leppin1, Tobias Görler1, Marco Cavedon1, Mike Dunne1, Elisabeth Wolfrum1, Frank Jenko1, and ASDEX Upgrade Team2 — 1Max Planck Institute for Plasma Physics, Boltzmannstraße 2, 85748 Garching b. München, Germany — 2See author list of U. Stroth et al. 2022 Nucl. Fusion 62 042006
The theoretical investigation of relevant turbulent transport mechanisms in H-mode pedestals is a great scientific and numerical challenge. In this study we address this challenge by global, nonlinear gyrokinetic simulations of a full pedestal up to the separatrix, supported by a detailed characterization of gyrokinetic instabilities at pedestal top, center and foot. We present ASDEX- Upgrade pedestal simulations (and first comparisons to other experiments) using the gyrokinetic, Eulerian, delta-f code GENE (genecode.org). We investigate the differences in turbulence characteristics between the pedestal regions via local simulations and obtain global heat flux profiles employing a new code upgrade which enables stable simulations at experimental beta values. In agreement with experimental measurements [Viezzer, PPCF, 2020] our global GENE simulations reveal a complex structure with different radial transport regimes. The dominant drive of electron turbulent transport transitions from ion-scale TEMs at pedestal top to small-scale ETG modes in the steep gradient region. Ion turbulent transport is relevant at the pedestal top but suppressed towards the pedestal center. A combination of linear and nonlinear stabilization mechanisms is identified to contribute to this heat flux structure.