Hannover 2010 – scientific programme

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P: Fachverband Plasmaphysik

P 13: Magnetic Confinement

P 13.10: Talk

Wednesday, March 10, 2010, 17:15–17:30, B 305

Investigation of passive edge emission at ASDEX Upgrade — •Eleonora Viezzer, Thomas Pütterich, Ralph Dux, Benedikt Geiger, Arne Kallenbach, Rachael McDermott, Dirk Wünderlich, and ASDEX Upgrade Team — Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching

The spectral lines emitted in the plasma edge of ASDEX Upgrade blend with the spectra of the active charge exchange recombination spectroscopy (CXRS) measurements. The latter give information on plasma rotation, ion temperature and impurity density and therefore, CXRS is used as a standard diagnostic in magnetic confinement fusion. Quantifying the passive edge component is important for the distinction between the active and the passive signal. Additionally, the passive component itself enables insight into the processes occurring in the plasma edge. A model to describe the passive edge emission of spectral lines at ASDEX Upgrade has been developed. Dedicated experiments have been analyzed and the line-of-sight integrated measurements have been deconvoluted by forward modelling. The obtained radial emissivity profiles have been compared with the radiation simulated by the 1-D transport code STRAHL in order to quantify the contribution of electron impact excitation and thermal charge exchange (tcx), which are the main processes of the passive emission lines. For the quantification of the tcx emission, a neutral H density profile has been determined by the analysis of the H_γ emission and Monte-Carlo modelling using KN1D.