Investigation of the Thomson scattering-ECE discrepancy in ICRF heated plasmas at Alcator C-Mod
Author(s)Austin, M. E.; Harvey, R. W.; Ma, Y.; Reinke, M. L.; White, Anne E.; Hubbard, Amanda E.; Hughes, Jerry W.; Bonoli, Paul T.; Bader, Andrew; Lin, Yijun; Wolfe, Stephen M.; Wukitch, Stephen James; ... Show more Show less
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This paper reports on new experiments at Alcator C-Mod that were performed in order to investigate the long-standing, unresolved discrepancy between Thomson scattering (TS) and electron cyclotron emission (ECE) measurements of electron temperature in high temperature tokamak plasmas. Ion cyclotron range of frequency (ICRF) heating is used to produce high temperature conditions where the type of TS-ECE discrepancy observed in the past at JET and TFTR should become observable. At Alcator C-Mod, plasmas with Te(0) up to 8 keV are obtained using ion cyclotron resonance heating (ICRH), ICRF mode conversion heating and a combination of the two heating methods in order to explore the hypothesis that the presence of ICRH-generated fast ions may be related to the discrepancy. In all high temperature cases, the TS and ECE measurements of electron temperature agree to within experimental uncertainties. We find no evidence for the type of discrepancy reported at JET and TFTR. These results show that the TS-ECE discrepancy does not depend on high temperatures alone and also that the presence of ICRH-generated fast ions is insufficient to cause the TS-ECE discrepancy.
DepartmentDavid H. Koch Institute for Integrative Cancer Research at MIT; Massachusetts Institute of Technology. Department of Nuclear Science and Engineering; Massachusetts Institute of Technology. Plasma Science and Fusion Center
White, A.E., A.E. Hubbard, J.W. Hughes, P.T. Bonoli, M.E. Austin, A. Bader, R.W. Harvey, et al. “Investigation of the Thomson scattering-ECE discrepancy in ICRF heated plasmas at Alcator C-Mod.” Nuclear Fusion 52, no. 6 (June 1, 2012): 063021.
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