Effect of the minority concentration on ion cyclotron resonance heating in presence of the ITER-like wall in JET

D. Van Eester, E. Lerche, P. Jacquet, V. Bobkov, A. Czarnecka, J.W. Coenen, L. Colas, K. Crombé, M. Graham, S. Jachmich, E. Joffrin, C.C. Klepper, V. Kiptily, M. Lehnen, C. Maggi, F. Marcotte, G. Matthews, M.-L. Mayoral, K. Mc Cormick, I. MonakhovM.F.F. Nave, R. Neu, C. Noble, J. Ongena, T. Pütterich, F. Rimini, E.R. Solano, G.J. van Rooij

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

3 Citations (Scopus)

Abstract

The most recent JET campaign has focused on characterizing operation with the «ITER-like» wall. One of the questions that needed to be answered is whether the auxiliary heating methods do not lead to unacceptably high levels of impurity influx, preventing fusion-relevant operation. In view of its high single pass absorption, hydrogen minority fundamental cyclotron heating in a deuterium plasma was chosen as the reference wave heating scheme in the ion cyclotron domain of frequencies. The present paper discusses the plasma behavior as a function of the minority concentration X[H] in L-mode with up to 4MW of RF power. It was found that the tungsten concentration decreases by a factor of 4 when the minority concentration is increased from X[H] ≈ 5% to X[H] % 20% and that it remains at a similar level when X[H] is further increased to 30%; a monotonic decrease in Beryllium emission is simultaneously observed. The radiated power drops by a factor of 2 and reaches a minimum at X[H] ≈ 20%. It is discussed that poor single pass absorption at too high minority concentrations ultimately tailors the avoidance of the RF induced impurity influx. The edge density being different for different minority concentrations, it is argued that the impact ICRH has on the fate of heavy ions is not only a result of core (wave and transport) physics but also of edge dynamics and fueling.

Original languageEnglish
Title of host publicationRadiofrequency Power in Plasmas - Proceedings of the 20th Topical Conference
PublisherAmerican Institute of Physics
Pages223-226
Number of pages4
ISBN (Print)9780735412101
DOIs
Publication statusPublished - 2014
Externally publishedYes
Event20th Topical Conference on Radiofrequency Power in Plasmas - Sorrento, Italy
Duration: 25 Jun 201328 Jun 2013

Publication series

NameAIP Conference Proceedings
Volume1580

Conference

Conference20th Topical Conference on Radiofrequency Power in Plasmas
CountryItaly
CitySorrento
Period25/06/1328/06/13

Keywords

  • ICRH
  • impurities
  • ITER-like wall
  • minority heating

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