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U.S. Department of Energy
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In-situ impurity measurements in PDX Edge plasma

Conference ·
OSTI ID:5152218
The surface analysis station of PDX combines several surface analysis techniques (AES, XPS, SIMS) for in-situ measurement of impurity fluxes in the edge-plasma. The major impurities deposited on a sample surface during nondiverted PDX discharges are oxygen, titanium (limiter material) and chlorine. The impurity fluxes measured at different radial positions decreased by a factor of ten from the plasma edge to the wall. The sample surface collecting the impurity ions is located behind a circular aperture. The observed broadening of the deposition profile of Ti relative to the aperture diameter enables an estimate to be made of the ratio of charge state/energy of Ti ions in the edge plasma. Time-resolved analyses of the deposited impurities are presented which indicate that the time behavior for various impurities may be quite different for different impurity species. This aspect is discussed in relation to probable impurity release mechanisms.
Research Organization:
Princeton Univ., NJ (USA). Plasma Physics Lab.
DOE Contract Number:
AM02-76CH03073
OSTI ID:
5152218
Report Number(s):
PPPL-1688; CONF-800455-18
Country of Publication:
United States
Language:
English