Exposures of tungsten nanostructures to divertor plasmas in DIII-D. (22nd January 2016)

• Record Type: Journal Article
• Authors: Rudakov, D L; Wong, C P C; Doerner, R P; Wright, G M; Abrams, T; Baldwin, M J; Boedo, J A; Briesemeister, A R; Chrobak, C P; Guo, H Y; Hollmann, E M; McLean, A G; Fenstermacher, M E; Lasnier, C J; Leonard, A W; Moyer, R A; Pace, D C; Thomas, D M; Watkins, J G
• Is Part Of: Physica scripta. Volume T167(2016:Feb.)
• Publication Date: 2016-01-22
• Subjects: tungsten -- W-fuzz -- DiMES -- divertor -- DIII-D; Physics -- Periodicals; 530.05
• DOI: 10.1088/0031-8949/T167/1/014055
• Languages: English
• ISSNs: 0031-8949

Abstract

Abstract: Tungsten nanostructures (W-fuzz) prepared in the PISCES-A linear device have been found to survive direct exposure to divertor plasmas in DIII-D. W-fuzz was exposed in the lower divertor of DIII-D using the divertor material evaluation system. Two samples were exposed in lower single null (LSN) deuterium H-mode plasmas. The first sample was exposed in three discharges terminated by vertical displacement event disruptions, and the second in two discharges near the lowered X-point. More recently, three samples were exposed near the lower outer strike point in predominantly helium H-mode LSN plasmas. In all cases, the W-fuzz survived plasma exposure with little obvious damage except in the areas where unipolar arcing occurred. Arcing is effective in W-fuzz removal, and it appears that surfaces covered with W-fuzz can be more prone to arcing than smooth W surfaces.