München 2019 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 18: Postersitzung

P 18.64: Poster

Donnerstag, 21. März 2019, 16:30–18:30, Foyer Audimax

Selected MHD phenomena observed in the first divertor campaign of Wendelstein 7-X — •Henning Thomsen for the The Wendelstein 7-X Team collaboration — Max Planck Institute for Plasma Physics, Wendelsteinstr. 1, 17491 Greifswald, Germany

The first divertor campaign in Wendelstein 7-X stellarator (W7-X) successfully finished in October 2018. The plasma duration could be extended to up to 100s in Hydrogen for an ECRH heating power of 2 MW. The plasma performance in Hydrogen could be enhanced with respect to previous campaigns by improving the wall conditioning. The peak heating power was 7 MW (ECRH / NBI).

Transiently, high performance plasmas with stored energies of up to W_dia=1 MJ (⟨ β ⟩ > 1 %) could be created by means of ECRH and pellet fueling for a quick ramp-up of the plasma density. During one experimental program a sudden decrease of the stored energy by 100 kJ has been observed. We present data analysis from the soft-X-ray tomography system, which enables the estimation of the location of the crash and compare the findings with data from crashes observed in plasmas with actively driven toroidal currents.

Another focus of the ongoing investigations covers the detection and identification of MHD mode activity and their dependency on the magnetic configuration as well as the heating scenario.