Predictions of HFS LHCD Absorption in DIII-D LH Commissioning Targets

POSTER

Abstract

High field side (HFS) lower hybrid current drive (LHCD) is predicted to improve accessibility and penetration over low field side launch, permitting efficient off-axis (⍴ ≈ 0.6-0.8) current drive. The first-ever HFS LHCD launcher has been installed on DIII-D and will be commissioned during the 2025 campaign. A set of target plasmas for commissioning has been identified for which high (50-100%) single pass absorption (SPA) is predicted, reducing the risk of undamped LH power damaging device components. These targets include a variety of plasmas, including L-mode and both toroidal field directions. Many are cleaning plasmas, allowing the bulk of commissioning to occur during startup, thereby making the best use of experimental run days. Due to mode conversion being the expected mechanism of N|| upshift, the optimal launched N|| for these plasmas can be counter-intuitive. This set of commissioning plasmas, together with a sensitivity study of the SPA on the launched N|| throughout the duration of each shot, is presented.

*Work supported by US DOE under DE-FC02-04ER54698, DE-SC0014264, and DE-SC0018090.

Presenters

  • Grant Rutherford

    • MIT PSFC

Authors

  • Grant Rutherford

    • MIT PSFC
  • Mirela Cengher

    • MIT PSFC
  • Ivan Garcia

    • MIT PSFC
  • Malcolm Gould

    • MIT PSFC
  • Evan Leppink

    • MIT PSFC
  • Yijun Lin

    • MIT PSFC
    • MIT Plasma Science and Fusion Center
  • Samuel Pierson

    • MIT PSFC
  • James Ridzon

    • MIT PSFC
  • Andrew Seltzman

    • MIT PSFC
  • Will Wright

    • MIT PSFC
  • Stephen James Wukitch

    • MIT
    • MIT PSFC