Turbulent Transport of Fast Ions in the Large Plasma Device (LAPD)

POSTER

Abstract

Due to gyroradius averaging and drift-orbit averaging, the transport of fast ions by microturbulence is often smaller than for thermal ions. In this experiment, Strong drift wave turbulence is observed in LAPD on gradients produced by a plate obstacle. Energetic lithium ions orbit through the turbulent region. Scans with a collimated analyzer and with probes give detailed profiles of the fast ion spatial distribution and of the fluctuating fields. The fast-ion transport decreases rapidly with increasing fast-ion gyroradius. Unlike the diffusive transport caused by Coulomb collisions, in this case the turbulent transport is non-diffusive. Analysis and simulation suggest that the fast ions interact ballistically with stationary two-dimensional electrostatic turbulence. The energy dependence of the transport is well explained by gyro-averaging theory. In new experiments, different sources and obstacles alter the drift-wave turbulence to modify the nature of the transport.

Authors

  • Shu Zhou

    University of California, Irvine

  • W.W. Heidbrink

    University of California-Irvine, University of California, Irvine, UC Irvine

  • R. McWilliams

    University of California, Irvine, UC Irvine

  • Heinrich Boehmer

    University of California, Irvine

  • Troy Carter

    UCLA, University of California, Los Angeles

  • Pavel Popovich

    University of California, Los Angeles

  • Shreekrishna Tripathi

    Department of Physics and Astronomy, UCLA, University of California, Los Angeles

  • Stephen Vincena

    UCLA, University of California, Los Angeles, UCLA Dept of Physics

  • Frank Jenko

    Max-Planck-Institut f\"ur Plasmaphysik