SMuK 2023 – scientific programme

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P: Fachverband Plasmaphysik

P 12: Poster II

P 12.34: Poster

Wednesday, March 22, 2023, 17:30–19:00, HSZ EG

Overview of the neutral gas pressures in Wendelstein 7-X under boronized wall conditions — •Victoria Haak, Sergey Bozhenkov, Yuhe Feng, Amit Kharwandikar, Thierry Kremeyer, Dirk Naujoks, Valeria Perseo, Georg Schlisio, and Uwe Wenzel — Max-Planck-Institut für Plasmaphysik, Greifswald, Germany

Gas exhaust is a key requirement for density control in a fusion device and, apart from the pumping speed and the subdivertor geometry, strongly dependent on the neutral gas pressure in the subdivertor and in front of the pumps. 13 neutral gas pressure gauges measured the neutral gas pressure in different locations in the plasma vessel of the stellarator Wendelstein 7-X during the first test divertor campaign, allowing for a detailed analysis of the neutral gas pressures, the compression ratios and the particle exhaust rates via the turbomolecular pumps in the different magnetic field configurations. Neutral gas pressures on the order of few 10^-4 mbar were measured in the subdivertor region, while the highest neutral gas pressure of 1.75*10^-3 mbar was obtained in the so-called high iota configuration featuring 4 edge magnetic islands per cross section. While measurements are only available in specific locations of the subdivertor, finite element simulations provide a detailed picture of the pressure distribution in the subdivertor volume.