Flow measurements in the edge plasma of Tore Supra

Abstract In recent years, the measurement of flow velocity of the plasma in the edge of tokamaks has gained in importance. The determination of this parameter is often done using electrostatic probe systems such as Mach probes or Gundestrup probes. A Gundestrup system was recently commissioned in Tore Supra. The perpendicular ( U ⊥ ) and parallel ( U // ) components of the velocity are determined from the six ion saturation currents using a neural network. The neural network was trained using ion saturation currents obtained from a two-dimensional kinetic code developed at Tore Supra. We will describe the Gundestrup probe and the neural network training, validation and implementation. Preliminary measurements in ergodic divertor discharges show U // and U ⊥ profiles that exhibit small-scale spatial modulations similar to those reported for the temperature profiles.