Simulation of turbulent impurity transport in Alcator C-Mod*

Theory/experiment comparisons are presented for impurity transport in H-mode and ITB discharges in Alcator C-Mod. The impurity profiles are hollow in H-mode and peaked for ITB. This range of profiles is a stringent test for theory and represents cases with significant impact on tokamak performance and particular interest for ITER. The data was selected to optimize the comparison: only one impurity charge state must be analyzed and simulated. H-mode is modeled with a new, generalized Hasegawa-Wakatani model that describes on equal footing the fueling ion, the impurity, and the electrons. The ITB is simulated using a 3-D global fluid code which includes two ion species and electrons which are introduced into the plasma with a fixed source. Transport is due to coupled ITG and TEM modes.