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

JOURNAL OF NUCLEAR MATERIALS

卷:363

Article; Proceedings Paper

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

关键词: DIII-D;    ELM;    stochastic boundary;    carbon impurities;    edge plasma;   

DOI  :  10.1016/j.jnucmat.2007.01.270

来源: Elsevier

【 摘 要 】

Large Type-l 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 (v(e)* similar to 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. 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. (c) 2007 Elsevier B.V. All rights reserved.

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