Measurement of central toroidal rotation in ohmic Tore Supra plasmas

The first simultaneous measurements of the toroidal rotation velocities of main (D+) and heavy impurity (Cr22+) ions in the core of ohmic plasmas are presented. For the main ions a system of five neutral particle (charge exchange) analysers is used, one having a near tangential line of sight. The velocities of the Cr22+ ions are obtained from the Doppler shift of X ray lines observed with a high resolution crystal spectrometer. Both ion species move in the direction opposite to the plasma current. The velocities are in the range 20-40 km/s. There is a strong indication that the toroidal motion is driven by the radial electric field created by ripple losses, as expected from neoclassical transport theory.