Destabilization of ellipticity-induced Alfvén eigenmodes during ICRF heating and stabilization by negative-ion-based neutral beam injection in JT-60U

Y. Kusama, G. Y. Fu, G. J. Kramer, M. Saigusa, T. Oikawa, T. Ozeki, S. Moriyama, F. V. Tchernychev, M. Nemoto, T. Kondoh, T. Hatae, K. Tobita, M. Kuriyama, C. Z. Cheng, H. Kimura

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

High-frequency modes in the 525-550 kHz range with toroidal mode numbers n = 3-7 were excited after the sawtooth crash during ion cyclotron range of frequency (ICRF) heating. Based on the stability analysis using the NOVA-K code, these modes were found to be consistent with ellipticity-induced Alfvén eigenmodes (EAEs) excited in the EAE gap located at the q = 1 surface. A change in the safety factor after the sawtooth crash was essential for the excitation of EAEs in the core region of the plasma. The high-frequency modes were stabilized by the neutral beam injection at 350 keV using negative-ion-based neutral beam (NNB) injectors. Stability analysis using the NOVA-K code has shown that NNB-injected ions enhance the damping of the EAEs and tend to stabilize them.

Original languageEnglish
Pages (from-to)1167-1177
Number of pages11
JournalPlasma Physics and Controlled Fusion
Volume41
Issue number9
DOIs
Publication statusPublished - 1999 Sep 1
Externally publishedYes

ASJC Scopus subject areas

  • Nuclear Energy and Engineering
  • Condensed Matter Physics

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    Kusama, Y., Fu, G. Y., Kramer, G. J., Saigusa, M., Oikawa, T., Ozeki, T., Moriyama, S., Tchernychev, F. V., Nemoto, M., Kondoh, T., Hatae, T., Tobita, K., Kuriyama, M., Cheng, C. Z., & Kimura, H. (1999). Destabilization of ellipticity-induced Alfvén eigenmodes during ICRF heating and stabilization by negative-ion-based neutral beam injection in JT-60U. Plasma Physics and Controlled Fusion, 41(9), 1167-1177. https://doi.org/10.1088/0741-3335/41/9/308