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Charge-exchange wall physical erosion rates for a proposed INTOR/FED limiter

Journal Article · · J. Vac. Sci. Technol., A; (United States)
DOI:https://doi.org/10.1116/1.572149· OSTI ID:5723650

We have analyzed power deposition and physical erosion rates on the first wall and limiter due to charge-exchange neutrals in a proposed pump limiter design for the INTOR/FED tokamak. Plasma conditions were modeled using the one-dimensional plasma transport code baldur. Neutral transport was modeled using a two-dimensional, multispecies Monte Carlo algorithm. No chemical erosion or wall redeposition processes were included. Two possible plasma discharges with different edge densities and temperatures were modeled, a regime with T/sub e/ approx.300 eV and napprox.5 x 10/sup 12/ cm/sup -3/, and a hotter, less dense edge regime produced with pellet fueling. We found that the erosion of the stainless steel vacuum vessel wall was highly localized in each case to the two points just beyond the limiter tips, and to the point directly across from the neutralizer plate, with peak erosion rates approx.2 cm/yr, assuming a 40% duty cycle. The erosion of a carbon limiter, neglecting redeposition and chemical erosion, varied in the two cases from 1.6--4 cm/yr, for the same duty cycle. The hotter, less dense discharge produced less sputtering. However achieving truly tolerable physical sputtering rates may require a very low edge temperature, plasma.

Research Organization:
Plasma Physics Laboratory, Princeton University, Princeton, New Jersey
DOE Contract Number:
AC02-76CH03073
OSTI ID:
5723650
Journal Information:
J. Vac. Sci. Technol., A; (United States), Journal Name: J. Vac. Sci. Technol., A; (United States) Vol. 1:2; ISSN JVTAD
Country of Publication:
United States
Language:
English