ORNL diagnostic and modeling development for LAPD ICRF experiments

POSTER

Abstract

PPPL, UCLA, and ORNL scientists have recently collaborated on a three week ICRF campaign at the upgraded LAPD device to study near field-plasma interactions associated with a single strap antenna driven at 2.38 MHz with 100 kW of RF power. This poster highlights ORNL involvement through implementation of the following diagnostics: an optical emission probe to measure neutral density, a retarding field energy analyzer to measure fast ions, phase locked imaging to measure line integrated RF-driven optical emission fluctuations, and an RF compensated triple Langmuir probe to measure density and temperature. To interpret the results of the experimental campaign a 3D cold plasma finite element model with realistic antenna and vacuum vessel geometry was developed in COMSOL. A summary of these results will be discussed. Highlights include a proof of principle localized and spatially resolved measurement of the neutral density, a strong increase in RF-driven optical emission fluctuations directly in front of the RF antenna strap, a shift in fast ion energies near the plasma edge, and qualitative agreement between the COMSOL cold plasma model with the various diagnostics.

Authors

  • R.C. Isler

    ORNL, Oak Ridge National Laboratory

  • J.B.O. Caughman

    ORNL, Oak Ridge National Lab., Oak Ridge National Laboratory

  • Cornwall Lau

    ORNL, Oak Ridge National Laboratory

  • E.H. Martin

    ORNL, Oak Ridge National Laboratory

  • Rory Perkins

    PPPL

  • Bart Van Compernolle

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

  • Steve Vincena

    UCLA, University of California at Los Angeles, vincena@physics.ucla.edu, Department of Physics, University of California, Los Angeles, Univ of California - Los Angeles

  • Shreekrishna Tripathi

    Univ of California - Los Angeles, UCLA, University of California Los Angeles

  • Walter Gekelman

    UCLA, University of California at Los Angeles, Department of Physics, University of California, Los Angeles, Univ of California - Los Angeles