Characteristics of Alfven eigenmodes, burst modes and chirping modes in the Alfven frequency range driven by negative ion based neutral beam injection in JT-60U

Y. Kusama, G. J. Kramer, H. Kimura, M. Saigusa, T. Ozeki, K. Tobita, T. Oikawa, K. Shinohara, T. Kondoh, M. Moriyama, F. V. Tchernychev, M. Nemoto, A. Morioka, M. Iwase, N. Isei, T. Fujita, S. Takeji, M. Kuriyama, R. Nazikian, G. Y. FuK. W. Hill, C. Z. Cheng

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Abstract

The excitation and stabilization of Alfven eigenmodes and their impact on energetic ion confinement were investigated with negative ion based neutral beam injection at 330-360 keV into weak or reversed magnetic shear plasmas on JT-60U. Toroidicity induced Alfven eigenmodes (TAEs) were observed in weak shear plasmas with 〈βh〉≥0.1% and 0.4≤vb∥/vA≤1. The stability of TAEs is consistent with predictions by the NOVA-K code. New burst modes and chirping modes were observed in the higher β regime of 〈βh〉≥0.2%. The effect of TAEs, burst modes and chirping modes on fast ion confinement has been found to be small so far. It was found that a strongly reversed shear plasma with internal transport barrier suppresses AEs.

Original languageEnglish
Pages (from-to)1837-1843
Number of pages7
JournalNuclear Fusion
Volume39
Issue numberSpecial Issu
DOIs
Publication statusPublished - 1999 Dec 1
Externally publishedYes

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Condensed Matter Physics

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    Kusama, Y., Kramer, G. J., Kimura, H., Saigusa, M., Ozeki, T., Tobita, K., Oikawa, T., Shinohara, K., Kondoh, T., Moriyama, M., Tchernychev, F. V., Nemoto, M., Morioka, A., Iwase, M., Isei, N., Fujita, T., Takeji, S., Kuriyama, M., Nazikian, R., ... Cheng, C. Z. (1999). Characteristics of Alfven eigenmodes, burst modes and chirping modes in the Alfven frequency range driven by negative ion based neutral beam injection in JT-60U. Nuclear Fusion, 39(Special Issu), 1837-1843. https://doi.org/10.1088/0029-5515/39/11Y/324