Constraining the divertor heat width in ITER
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Whyte_Constraining the.pdf
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Author(s)
Whyte, Dennis G.
Labombard, Brian
Hughes, Jerry W., Jr.
Lipschultz, Bruce
Terry, James L.
Brunner, Daniel Frederic
Stangeby, P. C.
Elder, D.
Leonard, A. W.
Watkins, J.
Date Issued
January 2013
Journal
Journal of Nuclear Materials
Publisher
Elsevier
Citation
Whyte, D. G., B. LaBombard, J.W. Hughes, B. Lipschultz, J. Terry, D. Brunner, P. C. Stangeby, D. Elder, A. W. Leonard, and J. Watkins. "Constraining the divertor heat width in ITER." Journal of Nuclear Materials 438, Supplement (July 2013), pp.S435-S439.
Version
Author's final manuscript
Abstract
A model is developed which constrains heat width, λr based on global power balance, momentum conservation, pedestal stability and sheath heat transmission. The model relies on measurements of the ratio of separatrix to pedestal pressure; a ratio ∼5% is found to be expected for ITER. Applying this model indicates a constraint that the allowed λr ∼ 10–30 mm for ITER if the divertor is in the high-recycling regime as expected (T < 20 eV) while a λr ∼ 1–3 mm requires a separatrix pressure approximately equal to the top pedestal pressure in violation of physical reasoning and the concept of a pedestal. A weaker constraint is applied in the model that upstream separatrix temperature simultaneously satisfies power balance. The constrained model cannot satisfy power balance with λr < 3 mm, and in order to obtain λr ∼ 5 mm requires divertor plasma temperature >100 eV, a condition which would have very negative consequences for the divertor, but has never been observed experimentally.
MIT Department
Massachusetts Institute of Technology. Plasma Science and Fusion Center
Terms of Use
Creative Commons Attribution-NonCommercial-NoDerivs License
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DOI of Published Version
https://doi.org/10.1016/j.jnucmat.2013.01.088
