Observation of non-locality of parametric decay during rf injection experiments on TST-2

POSTER

Abstract

Investigation of linear/nonlinear wave energy transfer in spectral and real spaces of plasma is important for understanding complex plasma structural formation. We present an experimental observation of non-locality of parametric decay instability (PDI) during rf injection experiments in the TST-2 spherical tokamak. The PDI is considered to be mainly associated with pump wave (high harmonic fast wave, HHFW), lower-sideband (HHFW or ion Bernstein wave), and ion cyclotron quasi-mode (ICQM). PDI is a nonlinear and local phenomenon. However, the PDI is widely observed in various locations inside the vessel, and the same frequency matching condition is satisfied beyond difference of local ion cyclotron frequencies at observation locations. We discuss origin of the non-locality in term of wave propagation and coupling phase.

*This work is supported by grant-in-aids for Scientific Research S (21226021) and for Scientific Research A (21246137) of MEXT, Japan.

Authors

  • Yoshihiko Nagashima

    • University of Tokyo
    • Univ. Tokyo
    • The University of Tokyo

  • Takuya Oosako

    • Univ. Tokyo
    • The University of Tokyo
    • University of Tokyo

  • Yuichi Takase

    • University of Tokyo
    • The University of Tokyo
    • Univ. Tokyo

  • Akira Ejiri

    • University of Tokyo
    • Univ. Tokyo
    • The University of Tokyo

  • Osamu Watanabe

    • University of Tokyo
    • The University of Tokyo

  • Hiroaki Kobayashi

    • University of Tokyo
    • Univ. Tokyo
    • The University of Tokyo

  • Takashi Yamaguchi

    • University of Tokyo
    • The University of Tokyo

  • Bung Il An

    • University of Tokyo
    • Univ. Tokyo
    • The University of Tokyo
    • MIT

  • Hiroki Kurashina

    • University of Tokyo
    • The University of Tokyo

  • Kotaro Yamada

    • University of Tokyo
    • The University of Tokyo

  • Hiroyuki Hayashi

    • University of Tokyo
    • The University of Tokyo

  • Hazuki Matsuzawa

    • The University of Tokyo
    • University of Tokyo

  • Kentaro Hanashima

    • University of Tokyo
    • The University of Tokyo

  • Junichi Hiratsuka

    • University of Tokyo
    • The University of Tokyo

  • Hidetoshi Kakuda

    • University of Tokyo
    • The University of Tokyo

  • Takuya Sakamoto

    • University of Tokyo
    • The University of Tokyo

  • Takuma Wakatsuki

    • University of Tokyo
    • Univ. Tokyo
    • The University of Tokyo