SMuK 2021 – scientific programme

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P: Fachverband Plasmaphysik

P 17: Poster II

P 17.22: Poster

Friday, September 3, 2021, 14:00–16:00, P

Three-dimensional Finite Element Modelling of Magnetic Measurements of Tearing Modes in ASDEX Upgrade — •Magdalena Bauer, Marc Maraschek, Hartmut Zohm, Wolfgang Suttrop, Anja Gude, Felix Klossek, and the ASDEX Upgrade Team — Max Planck Institute for Plasma Physics, Garching

A tearing mode can be measured by various magnetic pick-up coil types characterized by their orientation and distance to the plasma and the surrounding conducting structures. Depending on the rotation frequency of the mode, screening currents are induced in these conductors that influence the magnetic measurements differently. A fast rotating mode can only be detected by the one coil type, whereas a locked mode signal is only available for the other type. In order to get a continuous description for all frequencies, a three-dimensional finite element model of the tokamak ASDEX Upgrade, including the geometry of the resonant surface of the tearing mode, the conducting vessel and passive stabilization loop (PSL), is implemented. The mode itself is described by a perturbation current density on the respective resonant surface from the equilibrium reconstruction. The simulated magnetic measurements of the mode, including the field of the mirror currents in the conducting structures, are used for a frequency dependent adaption of the experimentally determined magnetic perturbation field. The approach for adjusting the signals of the different types of magnetic measurements for various frequencies to get a unique perturbation amplitude, using the newly developed tool, is established and can be extended for the locked phase of the MHD mode.