München 2019 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 18: Postersitzung
P 18.59: Poster
Donnerstag, 21. März 2019, 16:30–18:30, Foyer Audimax
Dynamics of TESPEL injections in the W7-X stellarator observed with SXR tomography — •Christian Brandt1, Jonathan Schilling1, Henning Thomsen1, René Bussiahn1, Naoki Tamura2, Rainer Burhenn1, and and the W7-X Team1 — 1Max-Planck-Institute for Plasma Physics, Greifswald, Germany — 2National Institute for Fusion Science, 322-6 Oroshi-cho, Toki City, 509-5292 Japan
At the stellarator experiment Wendelstein 7-X (W7-X) a tracer-encapsulated solid pellet injection (TESPEL) system has been commissioned during the recent plasma operation phase OP1.2b (Jul-Oct 2018). The TESPELs represent well-known and well-localized sources of impurity atoms, starting effective X-ray emission after the thin shell of the pellet is ablated and the impurity atoms enter the hot plasma core (T>1 keV). The soft X-ray tomography system (XMCTS) – commissioned in OP1.2b – is capable to measure such dynamics by two-dimensional X-ray emissivity profiles in the up-down symmetric triangular plane with both high time resolution (sampling rate 2 MHz) and high spatial resolution (Δ x ≈ Δ y ≈ 4 cm). After injection of the tracer impurity pellets into the plasma volume radially localized perturbations of the equilibrium are observed in the 2D X-ray emissivity profiles. Investigations of the poloidal propagation and the spatiotemporal evolution of the perturbations created by the tracer impurity injections are presented.