Erlangen 2018 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 11: Helmholtz Graduate School - Poster

P 11.10: Poster

Dienstag, 6. März 2018, 16:15–18:15, Redoutensaal

Radial Electric Field Studies in the Near Scrape-off Layer of ASDEX Upgrade using Charge Exchange Recombination Spectroscopy — •Ulrike Plank^1,2, Thomas Pütterich^1,2, Marco Cavedon¹, Michael Griener¹, Eleonora Viezzer³, Ulrich Stroth¹, and ASDEX Upgrade Team¹ — ¹Max Planck Institute for Plasma Physics, Garching, Germany — ²Faculty of Physics, Ludwig Maximilian University of Munich, Germany — ³Department of Atomic, Molecular and Nuclear Physics, University of Seville, Spain

The high confinement mode (H-mode) is a regime of magnetically confined fusion plasmas with improved particle and energy confinement. It exhibits a transport barrier in the confined region, close to the last closed flux surface (LCFS). This barrier is caused by a shear of the radial electric field (E_r). However, it is still discussed whether the E_r shear in the near scrape-off layer (SOL), i.e. outside the LCFS, influences the formation of the transport barrier and, therefore, the transition into H-mode. In order to measure E_r in the near SOL, a new charge exchange (CX) recombination spectroscopy diagnostics was installed at ASDEX Upgrade, which is capable of measuring E_r with high radial resolution by investigating CX reactions of low-Z impurity ions with injected neutrals. The new system utilizes a piezo valve for the injection of neutrals, which provides locally high neutral densities in the near SOL. The characterization of different CX lines from fully and partially ionized impurities will be presented together with first measurements of the new diagnostics.