Impurity toroidal rotation and transport in Alcator C-Mod ohmic h-mode plasmas

Central toroidal rotation and impurity transport coe cients have been determined in Alcator C-Mod Ohmic High Con nement Mode (H-mode) plasmas from observations of x-ray emission following impurity injection. Rotation velocities up to 3 10 m/s in the co-current direction have been observed in the center of the best Ohmic H-mode plasmas. Purely Ohmic H-mode plasmas display many characteristics similar to Ion Cyclotron Range of Frequencies (ICRF) heated H-mode plasmas, including the scaling of the rotation velocity with plasma parameters and the formation of edge pedestals in the electron density and temperature pro les. Very long impurity con nement times ( 1 s) are seen in Edge Localized Mode-free (ELM-free) Ohmic H-modes and the inward impurity convection velocity pro le has been determined to be close to the calculated neo-classical pro le.