SMuK 2021 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 5: Poster I
P 5.25: Poster
Dienstag, 31. August 2021, 14:00–16:00, P
Determination of (quasi) coherent mode properties at the edge of improved confinement plasmas — •Joey Kalis1,2, Gregor Birkenmeier1,2, Michael Griener2, Peter Manz3, Takashi Nishizawa2, Luiš Gil4, and Ulrich Stroth1,2 — 1Physik-Department E28, TUM, Garching — 2Max-Planck-Institut für Plasmaphysik, Garching — 3Institut für Physik, Universität Greifswald, Greifswald — 4Instituto de Plasmas e Fusão Nuclear, Universidade de Lisboa, Lisboa, Portugal
For future reactors based on the tokamak concept, it is necessary to establish the high confinement modes without type-I ELMs. In the past years, several natural ELM-free operation scenarios, such as the EDA H-mode, the I-mode and the QH-mode, have been achieved in ASDEX Upgrade. Each scenario is characterized by the appearance of quasi coherent fluctuations at the plasma edge, which may be responsible for the stabilization of the ELMs. For the comparison with theory, it is important to analyze the properties of all edge modes in more detail to identify their underlying driving forces and outline possible similarities and differences. The first focus is on the quasi-coherent mode (QCM), being present in the EDA H-mode. Due to its high spatial and temporal resolution, the He-beam diagnostic is used to outline different QCM properties. First, a time series analysis is performed to investigate the interaction of the QCM with other modes and general plasma parameters. Second, the propagation velocity and the wavenumber of the QCM is determined by means of spectral methods and compared with theoretical predictions.