Pedestal, SOL and divertor plasma properties in DIII-D RMP ELM-suppressed discharges at ITER relevant edge collisionality

M. E. Fenstermacher*, T. E. Evans, R. A. Moyer, G. D. Porter, J. A. Boedo, K. H. Burrell, M. Groth, I. Joseph, T. H. Osborne, J. G. Watkins

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

25 Citations (Scopus)

Abstract

Large Type-I edge localized modes (ELMs) were completely suppressed by applying edge resonant magnetic perturbations (RMPs) in DIII-D H-mode plasmas with the same low pedestal collisionality (ν e * ∼ 0.1) as in ITER. The RMP suppressed ELMs by reducing the edge pressure gradient through a reduction in the pedestal density gradient. Divertor emission profiles showed increases in toroidally localized D α and carbon ion emission and carbon emission throughout both divertor legs. The lowest density ELM-suppressed discharges showed elevated levels of carbon in the core plasma. The data and boundary simulations indicate that the divertor strikepoints make a transition from a high recycling regime during the ELMing phase to a sheath-limited regime during ELM suppression in the lowest density plasmas. ELM suppression during scans of RMP amplitude, injected power and density suggests a possible optimum combination of these actuators for ELM control, without elevated impurity levels, that is extrapolatable to ITER.

Original languageEnglish
Pages (from-to)476-483
Number of pages8
JournalJournal of Nuclear Materials
Volume363-365
DOIs
Publication statusPublished - 15 Jun 2007
MoE publication typeA1 Journal article-refereed

Keywords

  • Carbon impurities
  • DIII-D
  • Edge plasma
  • ELM
  • Stochastic boundary

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