Erlangen 2018 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 11: Helmholtz Graduate School - Poster

P 11.29: Poster

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

Fast-ion transport study in the plasma periphery of ASDEX Upgrade using FIDA spectroscopy — •A. Jansen van Vuuren, B. Geiger, P.A. Schneider, A. Jacobsen, T. Lunt, and The ASDEX Upgrade Team — Max-Planck-Institut fur Plasmaphysik, D-85748 Garching, Germany

Good confinement of fast-ions is mandatory in fusion plasmas since these supra-thermal particles are responsible for plasma heating and current-drive. However, plasma perturbations such as edge localized modes (ELMs) might degrade the fast-ion confinement and the corresponding losses could even damage plasma facing components.

One powerful tool to study confined fast ions in fusion experiments is fast-ion D-alpha (FIDA) spectroscopy which makes use of Doppler shifted radiation, emitted by fast ions after charge exchange reactions.

The FIDA method has now been applied to study the fast-ion distribution function in the plasma edge of ASDEX Upgrade. A specialized FIDA spectrometer has been designed to acquire simultaneously the FIDA emission and the un-shifted D-alpha emission from background neutrals. The latter allows to estimate the background neutral density profile, the main reaction partner for the charge exchange reaction at the edge. The new system can be operated through a burst mode, allowing measurements with exposure times down to hundreds of microseconds. First measurements show strongly reduced FIDA signal intensities after ELMs that can in part be explained by fast-ion losses.