S. Kitajima, H. Takahashi, K. Ishii, J. Sato, T. Ambo, M. Kanno, A. Okamoto, M. Sasao, S. Inagaki, M. Takayama, S. Masuzaki, M. Shoji, N. Ashikawa, M. Tokitani, M. Yokoyama, Y. Suzuki, T. Shimozuma, T. Ido, A. Shimizu, Y. Nagayama, T. Tokuzawa, K. Nishimura, T. Morisaki, S. Kubo, H. Kasahara, T. Mutoh, H. Yamada, Y. Tatematsu and LHD experimental group


Electrode Biasing Experiment in the Large Helical Device

Date of publication:

Nov. 2010

Key words:

22 IAEA Fusion Energy Conference, EXC/P8-07


The transition to the improved confinement mode by the electrode biasing was observed for the first time in the Large Helical Device (LHD). The negative resistance was observed in the confinement mode sustained by the cold electrode biasing. The electrode current showed the clear decrease against to the increase in the electrode voltage and had hysteresis in the transition phenomena. The decrease in the electrode current suggested the improvement of the radial particle transport. The increase in the energy confinement time and remarkable suppression of the density fluctuation, which correspond to the transition, were also observed. These results indicated that the electrode biased plasma in LHD showed the similar improvements in confinement to the observations in the H-mode plasma in tokamaks and stellarators.

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