Comparison of toroidal rotation velocities of different impurity ions in the DIII-D tokamak

The multiple ion species toroidal rotation velocities of impurity ions in DIII-D tokamak plasma were analyzed. The toroidal rotation velocities were measured using charge exchange recombination (CER) spectroscopy of impurity species. The non-negligible effect of energy dependent charge exchange cross sections predicted difference in toroidal rotation velocities which included strong Z dependence. The difference in toroidal rotation velocities was found to be dominated by neoclassical processes. The difference between measured impurity rotation velocity and main ion rotation velocity was substantial.