Extension of the operational regime of the LHD towards a deuterium experiment

Y. Takeiri, T. Morisaki, M. Osakabe, M. Yokoyama, S. Sakakibara, H. Takahashi, Y. Nakamura, T. Oishi, G. Motojima, S. Murakami, K. Ito, A. Ejiri, S. Imagawa, S. Inagaki, M. Isobe, S. Kubo, S. Masamune, T. Mito, I. Murakami, K. NagaokaK. Nagasaki, K. Nishimura, M. Sakamoto, R. Sakamoto, T. Shimozuma, K. Shinohara, H. Sugama, K. Y. Watanabe, J. W. Ahn, N. Akata, T. Akiyama, N. Ashikawa, J. Baldzuhn, T. Bando, E. Bernard, F. Castejón, H. Chikaraishi, M. Emoto, T. Evans, N. Ezumi, K. Fujii, H. Funaba, M. Goto, T. Goto, D. Gradic, Y. Gunsu, S. Hamaguchi, H. Hasegawa, Y. Hayashi, C. Hidalgo, T. Higashiguchi, Y. Hirooka, Y. Hishinuma, R. Horiuchi, K. Ichiguchi, K. Ida, T. Ido, H. Igami, K. Ikeda, S. Ishiguro, R. Ishizaki, A. Ishizawa, A. Ito, Y. Ito, A. Iwamoto, S. Kamio, K. Kamiya, O. Kaneko, R. Kanno, H. Kasahara, D. Kato, T. Kato, K. Kawahata, G. Kawamura, M. Kisaki, S. Kitajima, W. H. Ko, M. Kobayashi, S. Kobayashi, T. Kobayashi, K. Koga, A. Kohyama, R. Kumazawa, J. H. Lee, D. López-Bruna, R. Makino, S. Masuzaki, Y. Matsumoto, H. Matsuura, O. Mitarai, H. Miura, J. Miyazawa, N. Mizuguchi, C. Moon, S. Morita, T. Moritaka, K. Mukai, T. Muroga, S. Muto, T. Mutoh, T. Nagasaka, Y. Nagayama, N. Nakajima, Y. Nakamura, H. Nakanishi, H. Nakano, M. Nakata, Y. Narushima, D. Nishijima, A. Nishimura, S. Nishimura, T. Nishitani, M. Nishiura, Y. Nobuta, H. Noto, M. Nunami, T. Obana, K. Ogawa, S. Ohdachi, M. Ohno, N. Ohno, H. Ohtani, M. Okamoto, Y. Oya, T. Ozaki, B. J. Peterson, M. Preynas, S. Sagara, K. Saito, H. Sakaue, A. Sanpei, S. Satake, M. Sato, T. Saze, O. Schmitz, R. Seki, T. Seki, I. Sharov, A. Shimizu, M. Shiratani, M. Shoji, C. Skinner, R. Soga, T. Stange, C. Suzuki, Y. Suzuki, S. Takada, K. Takahata, A. Takayama, S. Takayama, Y. Takemura, Y. Takeuchi, H. Tamura, N. Tamura, H. Tanaka, K. Tanaka, M. Tanaka, T. Tanaka, Y. Tanaka, S. Toda, Y. Todo, K. Toi, M. Toida, M. Tokitani, T. Tokuzawa, H. Tsuchiya, T. Tsujimura, K. Tsumori, S. Usami, J. L. Velasco, H. Wang, T. H. Watanabe, T. Watanabe, J. Yagi, M. Yajima, H. Yamada, I. Yamada, O. Yamagishi, N. Yamaguchi, Y. Yamamoto, N. Yanagi, R. Yasuhara, E. Yatsuka, N. Yoshida, M. Yoshinuma, S. Yoshimura, Y. Yoshimura

Research output: Contribution to journalArticlepeer-review

52 Citations (Scopus)

Abstract

As the finalization of a hydrogen experiment towards the deuterium phase, the exploration of the best performance of hydrogen plasma was intensively performed in the large helical device. High ion and electron temperatures, T i and T e, of more than 6 keV were simultaneously achieved by superimposing high-power electron cyclotron resonance heating onneutral beam injection (NBI) heated plasma. Although flattening of the ion temperature profile in the core region was observed during the discharges, one could avoid degradation by increasing the electron density. Another key parameter to present plasma performance is an averaged beta value . The high regime around 4% was extended to an order of magnitude lower than the earlier collisional regime. Impurity behaviour in hydrogen discharges with NBI heating was also classified with a wide range of edge plasma parameters. The existence of a no impurity accumulation regime, where the high performance plasma is maintained with high power heating >10 MW, was identified. Wide parameter scan experiments suggest that the toroidal rotation and the turbulence are the candidates for expelling impurities from the core region.

Original languageEnglish
Article number102023
JournalNuclear Fusion
Volume57
Issue number10
DOIs
Publication statusPublished - 2017 Aug 21

Keywords

  • high beta plasma
  • impurity transport
  • internal transport barrier
  • stellarator/heliotron

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Condensed Matter Physics

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