Observation of a critical gradient threshold for electron temperature fluctuations in the DIII-D tokamak

  • J. C. Hillesheim
  • , J. C. Deboo
  • , W. A. Peebles
  • , T. A. Carter
  • , G. Wang
  • , T. L. Rhodes
  • , L. Schmitz
  • , G. R. McKee
  • , Z. Yan
  • , G. M. Staebler
  • , K. H. Burrell
  • , E. J. Doyle
  • , C. Holland
  • , C. C. Petty
  • , S. P. Smith
  • , A. E. White
  • , L. Zeng

Research output: Contribution to journalArticlepeer-review

55 Scopus citations

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 LTe-1=Te|/Te and toroidal rotation were varied, long wavelength (kθρs0.4) electron temperature fluctuations exhibit a threshold in LTe-1: below, they change little; above, they steadily increase. The increase in δTe/Te 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 Te-driven trapped electron mode turbulence.

Original languageEnglish
Article number045003
JournalPhysical Review Letters
Volume110
Issue number4
DOIs
StatePublished - Jan 23 2013
Externally publishedYes

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