Strong electron heating in CHS ICRF heating experiments

S. Masuda, R. Kumazawa, K. Nishimura, T. Mutoh, T. Watari, F. Simbo, T. Seki, T. Ido, R. Akiyama, A. Ando, A. Ejiri, H. Idei, K. Ida, H. Iguchi, M. Isobe, M. Iwase, S. Kubo, K. Matsuoka, T. Morisaki, S. MoritaS. Mutoh, S. Murakami, S. Okamura, T. Ozaki, S. Sakakibara, M. Sasao, C. Takahashi, T. Kawamoto, K. Tanaka, J. Xu, H. Yamada, I. Yamada, D. A. Rasmussen, J. F. Lyon, J. B. Wilgen, D. E. Greenwood, D. J. Hoffman, E. F. Jaeger, M. Murakami

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

An ion cyclotron range of frequencies (ICRF) heating experiment was performed on the Compact Helical System (CHS) device in order to identify the problems in establishing this as a reliable heating method. Radiofrequency heating was applied to plasmas with two ion species produced by ECH. Stored energy increased up to 2.2 kJ with the application of a 590 kW ICRF heating pulse, giving a heating efficiency comparable to that of NBI heating. More importantly, the 'flat-top' of the stored energy was maintained during the pulse. Good heating was realized with 30% proton and 70% deuteron plasmas at high density (4 ×19 m-3). It was found that the best discharges are dominated by electron ICRF heating, which seems to be the reason for the successful results. On the contrary, a flat-top in stored energy has never been obtained in discharges where ion heating dominates. The loss of high energy ions with large pitch angles produced by ion heating appears to degrade the performance and limit the duration of the heating. A similar degradation was encountered in previous ICRF heating experiments in helical systems. A newly designed detector was used to study the loss of the helically trapped particles.

Original languageEnglish
Pages (from-to)53-68
Number of pages16
JournalNuclear Fusion
Volume37
Issue number1
DOIs
Publication statusPublished - 1997 Jan 1
Externally publishedYes

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Condensed Matter Physics

Fingerprint Dive into the research topics of 'Strong electron heating in CHS ICRF heating experiments'. Together they form a unique fingerprint.

  • Cite this

    Masuda, S., Kumazawa, R., Nishimura, K., Mutoh, T., Watari, T., Simbo, F., Seki, T., Ido, T., Akiyama, R., Ando, A., Ejiri, A., Idei, H., Ida, K., Iguchi, H., Isobe, M., Iwase, M., Kubo, S., Matsuoka, K., Morisaki, T., ... Murakami, M. (1997). Strong electron heating in CHS ICRF heating experiments. Nuclear Fusion, 37(1), 53-68. https://doi.org/10.1088/0029-5515/37/1/I12