T
Takashi Nagashima
Researcher at Japan Atomic Energy Research Institute
Publications - 39
Citations - 446
Takashi Nagashima is an academic researcher from Japan Atomic Energy Research Institute. The author has contributed to research in topics: Tokamak & Dielectric heating. The author has an hindex of 9, co-authored 39 publications receiving 434 citations.
Papers
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Journal ArticleDOI
Experimental Observation of the rf-Driven Current by the Lower-Hybrid Wave in a Tokamak
Takumi Yamamoto,Tsuyoshi Imai,Michiya Shimada,Norio Suzuki,Masaki Maeno,Shigeru Konoshima,T. Fujii,Kazuya Uehara,Takashi Nagashima,A. Funahashi,Noboru Fujisawa +10 more
TL;DR: In this paper, it was observed that the waves launched from a phased array antenna of four waveguides couple effectively with electrons under the condition of ε = 2.0.
Journal ArticleDOI
Improved tokamak concept focusing on easy maintenance
Satoshi Nishio,Shuzo Ueda,Isao Aoki,R. Kurihara,T. Kuroda,H. Miura,Tomoaki Kunugi,Yasushi Seki,Takashi Nagashima,M. Ohta,Adachi Junichi,S. Yamazak,Kawaguchi Ichiro,T. Hashimoto,K. Shinya,Y. Murakami,Haruhiko Takase,T. Nakamura +17 more
TL;DR: In this paper, a torus system is radially divided into equal sectors and each sector forms an assembly unit, all the piping and feeder systems are extracted to the spacious torus central region.
Journal ArticleDOI
Parametric Instabilities in Lower-Hybrid-Frequency Heating of a Tokamak
Tsuyoshi Imai,Takashi Nagashima,Takumi Yamamoto,Kazuya Uehara,Shigeru Konoshima,Takeuchi Hideji,H. Yoshida,Noboru Fujisawa +7 more
TL;DR: In this paper, the decay spectra during the rf heating were identified as the parametric decay into the cold lower hybrid waves and the ion-cyclotron waves at the plasma surface.
Journal ArticleDOI
Development of d.c. power supply for gyrotron with energy recovery system
Masaki Tsuneoka,H. Fujita,Keishi Sakamoto,Atsushi Kasugai,Tsuyoshi Imai,Takashi Nagashima,Toshio Asaka,N. Kamioka,M. Yasuda,Toshimitsu Iiyama,T. Yoshida,H. Nara,M. Ishibashi +12 more
TL;DR: In this article, a new type of power supply system for a gyrotron with collector potential depression (CPD) to enhance the efficiency of the gyroron was developed.
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Development of 170 GHz/500 kW gyrotron
Keishi Sakamoto,Atsushi Kasugai,Masaki Tsuneoka,Koji Takahashi,Y. Ikeda,Tsuyoshi Imai,Takashi Nagashima,M. Ohta,Tsuyoshi Kariya,K. Hayashi,Yoshika Mitsunaka,Yosuke Hirata,Yasuyuki Itoh,Y. Okazaki +13 more
TL;DR: A development of 170GHz/500kW level gyrotron was carried out as R&D work of ITER as discussed by the authors, which achieved a short pulse experiment, the maximum power of 750kW was achieved at 85kV/40A.