Observation of a Critical Gradient Threshold for Electron Temperature Fluctuations in the DIII-D Tokamak
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Hillesheim-2013-Observation of a Critical Gradient Threshold for Electron Temperature.pdf
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Author(s)
White, Anne E.
Hillesheim, J. C.
DeBoo, J. C.
Peebles, W. A.
Carter, T. A.
Wang, G.
Rhodes, T. L.
Schmitz, L.
McKee, G. R.
Yan, Z.
Date Issued
January 2013
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Hillesheim, J. C. et al. “Observation of a Critical Gradient Threshold for Electron Temperature Fluctuations in the DIII-D Tokamak.” Physical Review Letters 110.4 (2013). ©2013 American Physical Society
Version
Final published version
Abstract
A critical gradient threshold has been observed for the first time in a systematic, controlled experiment for a locally measured turbulent quantity in the core of a confined high-temperature plasma. In an experiment in the DIII-D tokamak where L[subscript T[subscript e]][superscript -1]=|∇T[subscript e]|/T[subscript e] and toroidal rotation were varied, long wavelength (k[subscript θρs]≲0.4) electron temperature fluctuations exhibit a threshold in L[subscript T[subscript e]][superscript -1]: below, they change little; above, they steadily increase. The increase in δT[subscript e]/T[subscript e] is concurrent with increased electron heat flux and transport stiffness. Observations were insensitive to rotation. Accumulated evidence strongly enforces the identification of the experimentally observed threshold with ∇T[subscript e]-driven trapped electron mode turbulence.
MIT Department
Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
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DOI of Published Version
https://doi.org/10.1103/PhysRevLett.110.045003
