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

Journal Article · Fri Oct 31 00:00:00 EDT 2014 · Journal of Nuclear Materials

DOI:https://doi.org/10.1016/j.jnucmat.2014.10.056· OSTI ID:1266857

Rudakov, D. L. ^[1]; Stangeby, P. C. ^[2]; Wong, C. P. C. ^[3]; McLean, A. G. ^[4]; Wampler, W. R. ^[5]; Watkins, J. G. ^[6]; Boedo, J. A. ^[1]; Briesemeister, Alexis R. ^[7]; Buchenauer, Dean A. ^[6]; Chrobak, C. P. ^[3]; Elder, J. D. ^[2]; Fenstermacher, M. E. ^[4]; Guo, H. Y. ^[3]; Lasnier, C. J. ^[4]; Leonard, A. W. ^[3]; Maingi, R. ^[8]; Moyer, R. A. ^[1]

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1. Univ. of California, San Diego, La Jolla, CA (United States)
2. Univ. of Toronto Institute for Aerospace Studies, Toronto (Canada)
3. General Atomics, San Diego, CA (United States)
4. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
5. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
6. Sandia National Lab. (SNL-CA), Livermore, CA (United States)
7. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
8. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

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 ¹³CH₄ and one exposure with D₂ 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 ¹³CH₄ injection was below the measurement resolution of 0.5 nm, corresponding to a rate of ≤0.04 nm/s. In conclusion, compared to the previously measured erosion rates, this constitutes a reduction by a factor of > 10.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1266857
• Journal Information: Journal of Nuclear Materials, Vol. 463, Issue C; ISSN 0022-3115
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

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