K
K. Nagaoka
Researcher at National Institutes of Natural Sciences, Japan
Publications - 159
Citations - 1986
K. Nagaoka is an academic researcher from National Institutes of Natural Sciences, Japan. The author has contributed to research in topics: Large Helical Device & Plasma. The author has an hindex of 25, co-authored 145 publications receiving 1826 citations. Previous affiliations of K. Nagaoka include Graduate University for Advanced Studies.
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Journal ArticleDOI
Heat and momentum transport of ion internal transport barrier plasmas on the Large Helical Device
K. Nagaoka,Katsumi Ida,Mikiro Yoshinuma,Yasuhiko Takeiri,Masayuki Yokoyama,S. Morita,Kenji Tanaka,Takeshi Ido,Akihiro Shimizu,Naoki Tamura,Hisamichi Funaba,Sadayoshi Murakami,Motoshi Goto,Hiroyuki R. Takahashi,Chihiro Suzuki,Yasuhiro Suzuki,Katsunori Ikeda,Masaki Osakabe,Katsuyoshi Tsumori,Haruhisa Nakano,Osamu Kaneko,Hiroshi Yamada +21 more
TL;DR: In this article, the ion internal transport barrier (ion ITB) was formed in the neutral beam heated plasmas on the Large Helical Device and the high-ion-temperature regime of helical plasma has been significantly extended, where the ion thermal diffusivity in the ion ITB plasma decreases down to the neoclassical transport level.
Journal ArticleDOI
Mitigation of NBI-driven Alfvén eigenmodes by electron cyclotron heating in the TJ-II stellarator
K. Nagaoka,T. Ido,E. Ascasíbar,T. Estrada,Shoji Yamamoto,A.V. Melnikov,A. Cappa,C. Hidalgo,M.A. Pedrosa,B. Ph. van Milligen,I. Pastor,Macarena Liniers,M. A. Ochando,Akihiro Shimizu,L.G. Eliseev,Shinsuke Ohshima,Kiyofumi Mukai,Y. Takeiri +17 more
TL;DR: Alfven eigenmode (AE) activity driven by NBI-produced fast ions is observed in TJ-II plasmas as discussed by the authors, and a two-step response of the measured AEs to electron cyclotron heating (ECH) power is seen.
Journal ArticleDOI
Alfvén eigenmode properties and dynamics in the TJ-II stellarator
A.V. Melnikov,L.G. Eliseev,Enrique Ascasibar,A.A. Chmyga,C. Hidalgo,T. Ido,R. Jiménez-Gómez,A.D. Komarov,A.S. Kozachek,L. I. Krupnik,S. M. Khrebtov,Axel Könies,Yu K Kuznetsov,A. López-Fraguas,S. E. Lysenko,V.A. Mavrin,K. Nagaoka,J.L. de Pablos,M. A. Pedrosa,S.V. Perfilov,Andrei Smolyakov,Donald A. Spong,M.V. Ufimtsev,Shoji Yamamoto +23 more
TL;DR: Alfven eigenmodes (AEs) were studied in neutral beam injection (NBI) heated plasmas in the TJ-II stellarator using a heavy ion beam probe (HIBP) in the core, and by Langmuir (LP) and Mirnov probes (MP) at the edge as mentioned in this paper.
Journal ArticleDOI
Integrated discharge scenario for high-temperature helical plasma in LHD
K. Nagaoka,Hiroto Takahashi,Sadayoshi Murakami,H. Nakano,Y. Takeiri,Hayato Tsuchiya,Masaki Osakabe,Katsumi Ida,Masayuki Yokoyama,Mikiro Yoshinuma,S. Morita,Motoshi Goto,T. Oishi,N. A. Pablant,Keisuke Fujii,K. A. Tanaka,Naoki Tamura,Y. Nakamura,Xiaodi Du,T. Ido,A. Shimizu,Shin Kubo,Hiroe Igami,Ryosuke Seki,Chihiro Suzuki,Yasuhiro Suzuki,Katsuyoshi Tsumori,Katsunori Ikeda,Masashi Kisaki,Y. Yoshimura,Takashi Shimozuma,Tetsuo Seki,K. Saito,Hiroshi Kasahara,Shuji Kamio,Takashi Mutoh,Osamu Kaneko,Hiroshi Yamada,A. Komori +38 more
TL;DR: In this article, the ion internal transport barrier (ITB) and electron ITB have been successfully integrated due to the superposition of centrally focused electron cyclotron heating to the ion ITB plasma, and the high temperature regime of the ion temperature comparable to the electron temperature has been significantly extended.
Journal ArticleDOI
Resistive interchange modes destabilized by helically trapped energetic ions in a helical plasma.
Xiaodi Du,Kazuo Toi,Masaki Osakabe,Masaki Osakabe,Satoshi Ohdachi,Satoshi Ohdachi,Takeshi Ido,Kenji Tanaka,Masayuki Yokoyama,Masayuki Yokoyama,Mikiro Yoshinuma,Mikiro Yoshinuma,Kunihiro Ogawa,K.Y. Watanabe,Mitsutaka Isobe,Mitsutaka Isobe,K. Nagaoka,K. Nagaoka,T. Ozaki,Satoru Sakakibara,Satoru Sakakibara,Ryosuke Seki,Akihiro Shimizu,Yasuhiro Suzuki,Yasuhiro Suzuki,Hayato Tsuchiya +25 more
TL;DR: A new bursting m=1/n=1 instability (m,n: poloidal and toroidal mode numbers) with rapid frequency chirping down has been observed for the first time in a helical plasma with intense perpendicular neutral beam injection, triggering an improvement of bulk plasma confinement.