Recent Results in Large Helical Device

Y. Nagayama, K. Ikeda, A. Komori, R. Kumazawa, S. Morita, N. Ohyabu, B. J. Peterson, S. Sakakibara, T. Shimozuma, H. Yamada, N. Ashikawa, H. Chikaraishi, M. Emoto, H. Funaba, P. Goncharov, M. Goto, Y. Hainada, K. Ida, T. Ido, H. IgamiS. Imagawa, S. Inagaki, A. Isayama, M. Isobe, A. Iwamoto, O. Kaneko, K. Kawahata, T. Kobuchi, Y. Kogi, S. Kubo, A. Mase, S. Masuzaki, K. Matsuoka, T. Minami, T. Mito, J. Miyazawa, T. Morisaki, S. Murakami, S. Muto, T. Mutoh, Y. Nakamura, H. Nakanishi, K. Narihara, Y. Narushima, A. Nishimura, K. Nishimura, A. Nishizawa, N. Noda, T. Notake, H. Nozato, S. Ohdachi, Y. Oka, M. Osakabe, S. Okajima, T. Ozaki, A. Sagara, K. Saito, M. Sakamotos, R. Sakamoto, M. Sasao, K. Sato, T. Seki, M. Shoji, S. Sudo, H. Suzuki, K. Takahata, Y. Takeiri, H. Takenaga, N. Tamura, K. Tanaka, K. Toi, T. Tokuzawa, Y. Torii, K. Tsumori, T. Uda, K. Y. Watanabe, I. Yamada, K. Yamazaki, N. Yanagi, M. Yokoyama, Y. Yoshimura, Y. Yoshinuma, T. Watari, O. Motojima

Research output: Chapter in Book/Report/Conference proceedingConference contribution


This paper presents recent experimental results in the Large Helical Device (LHD), which is the world largest helical system (Rax ∼ 3.6 m, aav ∼ 0.6 m, Bax ∼ 2.75 T) and has capability of steady state operation because of the super conducting magnets. LHD confines the plasma with Tio ∼ 2 keV and ne ∼ 0.8 x 1019 m -3 for 1905 sec using the ICRF heating. In this case, the total plasma heating energy was ∼ 1.3 GJ. This indicates that high energy ions generated by ICRF is well confined. Large magnetic island in the vacuum field due to the error field is vanished in plasma with higher temperature or with higher beta, so the error field is not an issue in helical systems. The obtained averaged beta is more than 4.3 % in LHD. Since the beta is not limited by the MHD events or magnetic island but the beta is limited by the lack of heating power, further improvement of beta can be expected. Internal and external transport barrier have been also observed, and the electron temperature and the ion temperature exceed 10 keV in the improved confinement mode in LHD. Besides the potential of the disruption free steady stated operation, LHD experiment accumulates evidences so that fusion reactor becomes more realistic.

Original languageEnglish
Title of host publication21st IEEE/NPS Symposium on Fusion Engineering, SOFE'05
Publication statusPublished - 2006
Externally publishedYes
Event21st IEEE/NPS Symposium on Fusion Engineering, SOFE'05 - Knoxville, TN, United States
Duration: Sept 26 2005Sept 29 2005

Publication series

NameProceedings - Symposium on Fusion Engineering


Other21st IEEE/NPS Symposium on Fusion Engineering, SOFE'05
Country/TerritoryUnited States
CityKnoxville, TN

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Nuclear Energy and Engineering


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