Erlangen 2018 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 12: Magnetic Confinement - Poster
P 12.10: Poster
Dienstag, 6. März 2018, 16:15–18:15, Redoutensaal
Transport properties of injected impurities in Wendelstein 7-X stellarator. — •Th. Wegner1, B. Geiger1, R. Burhenn1, B. Buttenschön1, D. Zhang1, A. Langenberg1, N. Pablant2, and The W7-X Team1 — 1Max-Planck-Institute for Plasma Physics, Greifswald, Germany — 2Princeton Plasma Physics Laboratory, Princeton, NJ, USA
Impurities in the plasma mainly influence the power balance. In particular, their existences increase the radiation losses and the dilution of the plasma. Especially in stellarators, impurities can be accumulated and cause an early pulse termination by radiation collapse. Hence, the investigation of the impurity transport properties is a demanding task for plasma devices with the potential of steady-state operation. Therefore, tracer impurities were injected by means of a new laser blow-off system on W7-X in a controlled manner. After the injection, the emission of several ionization states from the X-ray to XUV wavelength range were measured in different magnetic field configurations and plasma parameters. Simulation of their temporal behavior using measured radial profiles of the electron temperature and density allow access to transport properties. In particular, the impurity confinement time, the diffusion coefficient and the convection velocity will be presented for different impurity elements, plasma parameters and main plasma species.