July 2016

Journal

Control of high-Z PFC erosion by local gas injection in DIII-D

By:
Rudakov, D.L.; Stangeby, P.; Wong, Clement; McLean, A.G.; Wampler, W. R.; Watkins, J.; Boedo, J.; Wolfmeister, Alexis R; Buchenauer, Dean; Chrobak, C; Elder, J.; Fenstermacher, M. E.; Guo, H.; Lasnier, C.; Leonard, A. W.; Maingi, Rajesh; Moyer, R.A.
Journal Name:
Journal of Nuclear Materials
Page Number:
605-610
Volume:
463
Issue Number:
N/A
Publication Date:
July 20, 2016
View DOI Listing:
https://doi.org/10.1016/j.jnucmat.2014.10.056

Abstract

Reduced erosion of a high-Z PFC divertor surface was observed in DIII-D with local injection of methane and deuterium gases. Molybdenum-coated silicon samples were exposed in the lower divertor of DIII-D using DiMES under plasma conditions previously shown to cause significant net erosion of Mo. Three exposures with (CH4)-C-13 and one exposure with D-2 gas injection about 12 cm upstream of the samples located within 1-2 cm of the attached strike point were performed. Reduction of Mo erosion was evidenced in-situ by the suppression of MoI line radiation at 386.4 nm once the gas injection started. Post-mortem ion beam analysis demonstrated that the net erosion of molybdenum near the center of the samples exposed with (CH4)-C-13 injection was below the measurement resolution of 0.5 nm, corresponding to a rate of 10. (C) 2014 Elsevier B.V. All rights reserved.