Experiments and plans using lithium coatings on plasma-facing components in NSTX
Author: Henry W. Kugel
Submitted: 2005-12-21 12:05:31
Co-authors: H. Kugel, W. Blanchard, J. Dong, L. Dudek, R. Gernhardt, L. Guttadora, T. Holoman, S. Jurczynski, R. Kaita, G. Labik, R. Majeski, D. Mansfield, T. Provost, L. Roquemore, H. Schneider, P. Sichta, J. Timberlake
Princeton Plasma Physics Laboratory
PPPL, P. O. Box 451
Princeton, NJ 08543-0
Studies of the effects of lithium coatings on plasma-facing components (PFC’s) have begun on the National Spherical Torus Experiment (NSTX). Using a lithium pellet injector, a partial lithium coating on carbon PFC’s has been demonstrated to provide strong edge pumping, resulting in a reduction of recycling. These experiments were the first step in the three-phased approach to lithium PFC’s in NSTX. According to the 5-Year Plan, lithium pellet injection will be followed by lithium evaporation as a means of coating PFC’s. This second phase is about to begin, with the NSTX Experimental Schedule calling for the capability to perform routine Thick Lithium Coating depositions over a significant fraction of the plasma facing surfaces early in the 2006 experimental campaign. These experiments extend the work done in CDX-U on the effect of lithium coatings on high-Z surfaces to a larger scale device with a carbon wall. Lithium is chemically active on carbon, so the NSTX experiments will yield new information on the recycling properties of the lithium-carbon system. The results of these experiments will influence the decision to implement the third phase, which is a liquid lithium divertor. The status and plans for these elements of lithium PFC research on NSTX will be described.
Placement next to the poster "Low recycling discharges with full lithium wall coatings in CDX-U" if the CDX-U work is expected to be presented as a poster as well a talk.