@article{oai:nifs-repository.repo.nii.ac.jp:00000241,
 author = {Yoshimura,  Yasuo and Kubo,  Shin and Shimozuma,  Takashi and Igami,  Hiroe and Takahashi,  Hiromi and NISHIURA,  Masaki and OGASAWARA,  Shinya and MAKINO,  Ryohei and IDA,  Katsumi and YOSHINUMA,  Mikiro and SAKAKIBARA,  Satoru and TANAKA,  Kenji and NARIHARA,  Kazumichi and MUTOH,  Takashi and YAMADA,  Hiroshi and NAGASAKI,  Kazunobu and MARUSHCHENKO,  Nikolai B. and TURKIN,  Yuri},
 journal = {Plasma and Fusion Research},
 month = {Mar},
 note = {Electron cyclotron current drive (ECCD) is an attractive tool for controlling plasmas. In the large helical device (LHD), ECCD experiments have been performed by using an EC-wave power source, gyrotron, with a frequency of 84 GHz. The maximum driven current was ?9 kA with 100 kW injection power to plasma and 8 s duration of EC-wave pulse. These years, high-power and long-pulse 77 GHz gyrotrons were newly installed. An ECCD experiment with 775 kW injection power was performed. The 77 GHz waves of 8 s pulse duration sustained the plasmas. The EC-wave beam direction was scanned toroidally, keeping the beam direction aiming at the magnetic axis in X-mode polarization. In spite of the change in the EC-wave beam direction, plasma parameters such as the line-average electron density, the central electron temperature and the plasma stored energy were kept nearly the same values for the discharges, ?0.3 × 1019 m?3, ?3 keV and ?30 kJ, except for the plasma current. The plasma current showed a systematic change with the change in the beam direction for ECCD, and at an optimum direction with N//  ? ?0.3, the plasma current reached its maximum, ?40 kA. Also, current drive efficiency normalized with density and power was improved by 50% compared with that at the former 84 GHz ECCD experiment.},
 title = {ECCD Experiment Using an Upgraded ECH System on LHD},
 volume = {Vol. 7},
 year = {2012}
}