EPJ Web of Conferences (Jan 2015)

Recent Upgrading of ECRH System and Studies to Improve ECRH Performance in the LHD

  • Igami Hiroe,
  • Kubo Shin,
  • Shimozuma Takashi,
  • Yoshimura Yasuo,
  • Takahashi Hiromi,
  • Kamio Shuji,
  • Kobayashi Sakuji,
  • Ito Satoshi,
  • Mizuno Yoshinori,
  • Okada Kohta,
  • Makino Ryohei,
  • Ogasawara Shinya,
  • Kobayashi Kenya,
  • Osakabe Masaki,
  • Nagasaki Kazunobu,
  • Idei Hiroshi,
  • Mutoh Takashi

DOI
https://doi.org/10.1051/epjconf/20158702011
Journal volume & issue
Vol. 87
p. 02011

Abstract

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This paper reports the recent status of the ECRH system in the LHD and introduces the experimental results that suggest the reasonable effects of the wave-plasma interaction in the plasma boundary including outside the LCFS. With increasing the available ECRH power, ECRH/ECCD have been performed in higher density target plasmas where the mode coupling between the O-mode and the X-mode caused by the magnetic shear occurs for long distance in the low density region of the plasma boundary including the ergodic layer outside the LCFS. In such a case, the incident polarization should be set by taking into account the mode coupling effect. Moreover, the refraction in the boundary region should be considered for accurate numerical prediction of the wave trajectory and power absorption with use of the ray-tracing calculation.