Dependence of recycling and edge profiles on lithium evaporation in high triangularity, high performance NSTX H-mode discharges.
In this paper, the effects of a pre-discharge lithium evaporation variation on highly shaped discharges in the National Spherical Torus Experiment (NSTX) are documented. Lithium wall conditioning (‘dose’) was routinely applied onto graphite plasma facing components between discharges in NSTX, partly to reduce recycling. Reduced Dα emission from the lower and upper divertor and center stack was observed, as well as reduced midplane neutral pressure; the magnitude of reduction increased with the pre-discharge lithium dose. Improved energy confinement, both raw τE and H-factor normalized to scalings, with increasing lithium dose was also observed. At the highest doses, we also observed elimination of edge-localized modes. The midplane edge plasma profiles were dramatically altered, comparable to lithium dose scans at lower shaping, where the strike point was farther from the lithium deposition centroid. As a result, this indicates that the benefits of lithium conditioning should apply to the highly shaped plasmas planned in NSTX-U.
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- General Atomics, San Diego, CA (United States)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Columbia Univ., New York, NY (United States)
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Publication Date:
- OSTI Identifier:
- Report Number(s):
Journal ID: ISSN 0022-3115
- Grant/Contract Number:
- Accepted Manuscript
- Journal Name:
- Journal of Nuclear Materials
- Additional Journal Information:
- Journal Volume: 463; Journal ID: ISSN 0022-3115
- Research Org:
- Lawrence Livermore National Lab., Livermore, CA (United States)
- Sponsoring Org:
- Country of Publication:
- United States
- 70 PLASMA PHYSICS AND FUSION
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