Measured signatures of low energy, physical sputtering in the line shape of neutral carbon emission

JOURNAL OF NUCLEAR MATERIALS

卷:337

Article; Proceedings Paper

Brooks, NH ; Isler, RC ; Whyte, DG ; Fenstermacher, ME ; Groebner, RJ ; Stangeby, PC ; Heidbrink, WW ; Jackson, GL ; Mahdavi, MA ; West, WP

关键词: carbon;    helium;    impurity sources;    spectroscopy;    sputtering;   

DOI  :  10.1016/j.jnucmat.2004.10.058

来源: Elsevier

【 摘 要 】

The most important mechanisms for introducing carbon into the DIII-D divertors [J.L. Luxon, Nucl. Fusion 42 (2002) 614] are physical and chemical sputtering. Previous investigations have indicated that operating conditions where one or the other of these is dominant can be distinguished by using CD and C-2 emissions to infer C I influxes from dissociation of hydrocarbons and comparing to measured C I influxes. The present work extends these results through detailed analysis of the C I spectral line shapes. In general, it is found that the profiles are actually asymmetric and have shifted peaks. These features are interpreted as originating from a combination of an anisotropic velocity distribution from physical sputtering (the Thompson model) and an isotropic distribution from molecular dissociation. The present study utilitzes pure helium plasmas to benchmark C I spectral profiles arising from physical sputtering alone. (c) 2004 Elsevier B.V. All rights reserved.

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