ICRF wall conditioning: Present status and developments for future superconducting fusion machines

A. Lyssoivan, Raymond Koch, J. M. Noterdaeme, V. Philipps, D. Van Eester, M. Vervier, V. Rohde, V. Bobkov, G. Sergienko, E. De La Cal, H. G. Esser, E. Gauthier, D. A. Hartmann, D. Douai, F. Louche, N. Ashikawa, Y. D. Bae, B. Beaumont, A. Becoulet, S. BremondR. Dumont, M. Graham, J. Hu, J. G. Kwak, R. Laengner, P. U. Lamalle, E. Lerche, O. Marchuk, M. L. Mayoral, V. E. Moiseenko, I. Monakhov, M. Nightingale, J. Ongena, M. K. Paul, R. Pitts, V. Plyusnin, O. Schmitz, F. C. Schüller, M. Shimada, B. Unterberg, M. Van Schoor, G. Van Wassenhove, E. D. Volkov, T. Wauters, R. R. Weynants, Y. Zhao

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

Abstract

ITER and future superconducting fusion machines need efficient wall conditioning techniques for routine operation in between shots in the presence of permanent high magnetic field for wall cleaning, surface isotope exchange and to control the in-vessel long term tritium retention. Ion Cyclotron Wall Conditioning (ICWC) based on the ICRF discharge is fully compatible and needs the presence of the magnetic field. The present paper focuses on the principal aspects of the ICWC discharge performance in large-size fusion machines: (i) neutral gas RF breakdown with conventional ICRF heating antennas, (ii) antenna coupling with low density (∼1017m-3) RF plasmas and (iii) ICWC scenarios with improved RF plasma homogeneity in the radial and poloidal directions. All these factors were identified as crucial to achieve an enhanced conditioning effect (e.g. removal rates of selected "marker" masses). All the observed effects are analyzed in terms of RF plasma wave excitation/absorption and compared with the predictions from 1-D RF full wave and 0-D RF plasma codes. Numerical modeling and empirical extrapolation from the existing machines give good evidence for the feasibility of using ICWC in ITER with the main ICRF antenna.

Original languageEnglish
Title of host publicationRadio Frequency Power in plasmas - Proceedings of the 18th Topical Conference
Pages165-172
Number of pages8
DOIs
Publication statusPublished - 2009
Event18th Topical Conference on Radio Frequency Power in plasmas - Gent, Belgium
Duration: 24 Jun 200926 Jun 2009

Publication series

NameAIP Conference Proceedings
Volume1187
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Conference

Conference18th Topical Conference on Radio Frequency Power in plasmas
Country/TerritoryBelgium
CityGent
Period24/06/0926/06/09

Keywords

  • ICRF antennas
  • ICRF discharge
  • ITER
  • Tokamaks/stellarators
  • Toroidal/poloidal magnetic fields
  • Wall conditioning

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