Progress toward steady-state operation in LHD using electron cyclotron waves

Y. Yoshimura, S. Kubo, T. Shimozuma, H. Igami, H. Takahashi, S. Kobayashi, S. Ito, Y. Mizuno, Y. Takita, Y. Nakamura, K. Ohkubo, R. Ikeda, K. Ida, M. Yoshinuma, S. Sakakibara, T. Mutoh, K. Nagasaki, H. Idei, T. Notake

    研究成果: ジャーナルへの寄稿記事

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    Trials of steady-state operation (SSO) in the Large Helical Device (LHD) were started when a continuous wave (cw) gyrotron with the output power up to 0.2 MW was introduced to the electron cyclotron heating (ECH) system on LHD in 2003. During the first trial of SSO in the seventh LHD experimental campaign in 2004, severe temperature increase on the waveguide transmission line and, as a result, intense pressure increase in the evacuated waveguide occurred, which terminated the operation at 756 s. Additional pumping sections and cooling structures on the transmission line worked well, allowing a 3900-s sustainment of plasma with ne=0.15 ×1019 m-3 and Te0 = 1.7 keV by 0.1 MW injection power in 2005. The improvement of the ECH system by introducing cw gyrotrons with higher power for further improvement of plasma performance in SSO is in progress. Investigations on electron cyclotron current drive (ECCD) physics have been advanced a few years after the proof of ECCD in LHD. By obliquely injecting secondharmonic X-mode EC waves in toroidal direction, stable current up to 5.5 kA is driven, which was evaluated as a difference in plasma currents of the co-and counter-ECCD discharges with 0.1-MW EC wave power. It takes a few seconds for the driven current to saturate. Change in profile of rotational transform by ECCD and profile of driven current density are investigated by use of motional Stark effect measurement. Peaked and localized driven current profile at the plasma core region was confirmed for on-axis second-harmonic ECCD discharges.

    元の言語英語
    ページ(範囲)551-559
    ページ数9
    ジャーナルFusion Science and Technology
    58
    発行部数1
    DOI
    出版物ステータス出版済み - 1 1 2010

      フィンガープリント

    All Science Journal Classification (ASJC) codes

    • Civil and Structural Engineering
    • Nuclear and High Energy Physics
    • Nuclear Energy and Engineering
    • Materials Science(all)
    • Mechanical Engineering

    これを引用

    Yoshimura, Y., Kubo, S., Shimozuma, T., Igami, H., Takahashi, H., Kobayashi, S., ... Notake, T. (2010). Progress toward steady-state operation in LHD using electron cyclotron waves. Fusion Science and Technology, 58(1), 551-559. https://doi.org/10.13182/FST58-551