Max Planck Institute for Plasma Physics, Garching
Friday, July 22, 2016
The charge exchange recombination spectroscopy (CXRS) systems on ASDEX Upgrade (AUG) have been significantly expanded enabling complete profiles of the impurity ion temperature, toroidal rotation, poloidal rotation and density to be measured for multiple species on a discharge-to-discharge basis. These upgrades have enabled a wide variety of low-Z impurity transport and momentum transport investigations to be carried out in AUG. Using these systems, a database of He and B impurity density profiles covering a wide range of parameter space was assembled and then compared to quasi-linear gyrokinetic predictions using GKW. This comparison demonstrated that the theory systematically under-predicts the peaking of the impurity density profiles, although some trends in the data are correctly reproduced. The CXRS systems have also been used to investigate the intrinsic rotation in AUG L- and H-mode plasmas, with a particular emphasis on measurements in ohmic L-mode plasmas across the LOC-SOC transition. Previous work on this topic demonstrated that a change in the dominant turbulence type from TEM to ITG is insufficient to explain all of the AUG rotation changes. This result has been further investigated both from the experimental and theoretical side and the present status of the research will be presented in this talk.