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.
Presenters
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Grant Rutherford
MIT PSFC
Authors
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Grant Rutherford
MIT PSFC
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Mirela Cengher
MIT PSFC
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Ivan Garcia
MIT PSFC
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Malcolm Gould
MIT PSFC
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Evan Leppink
MIT PSFC
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Yijun Lin
MIT PSFC, MIT Plasma Science and Fusion Center
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Samuel Pierson
MIT PSFC
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James Ridzon
MIT PSFC
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Andrew Seltzman
MIT PSFC
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Will Wright
MIT PSFC
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Stephen James Wukitch
MIT, MIT PSFC