N
N. Isei
Researcher at Japan Atomic Energy Research Institute
Publications - 26
Citations - 663
N. Isei is an academic researcher from Japan Atomic Energy Research Institute. The author has contributed to research in topics: Tokamak & Plasma. The author has an hindex of 13, co-authored 26 publications receiving 650 citations.
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Journal ArticleDOI
Characteristics of Alfvén eigenmodes, burst modes and chirping modes in the Alfvén frequency range driven by negative ion based neutral beam injection in JT-60U
Y. Kusama,G. J. Kramer,Haruyuki Kimura,M. Saigusa,T. Ozeki,Kenji Tobita,T. Oikawa,Kouji Shinohara,Takashi Kondoh,M. Moriyama,F. V. Tchernychev,M. Nemoto,A. Morioka,M. Iwase,N. Isei,Takaaki Fujita,S. Takeji,Masaaki Kuriyama,Raffi Nazikian,Guoyong Fu,K. W. Hill,Chio-Zong Cheng +21 more
TL;DR: In this paper, the excitation and stabilization of Alfv?n eigenmodes and their impact on energetic ion confinement were investigated with negative ion based neutral beam injection at 330-360?keV into weak or reversed magnetic shear plasmas on JT-60U.
Journal ArticleDOI
Reduced transport and E r shearing in improved confinement regimes in JT-60U
Hiroshi Shirai,Mitsuru Kikuchi,Tomonori Takizuka,T. Fujita,Yoshihiko Koide,G. Rewoldt,D. R. Mikkelsen,Robert Budny,William Tang,Yasuaki Kishimoto,Yutaka Kamada,T. Oikawa,O. Naito,T. Fukuda,N. Isei,Yasunori Kawano,Masafumi Azumi,Jt Team +17 more
TL;DR: In this article, the global confinement and local transport properties of improved core confinement plasmas in JT-60U were studied in connection with Er shear formation in the Improved core confinement mode with internal transport barriers (ITBs), these are roughly classified into ''parabolic type" ITBs and ''box type'' ITBs.
Journal ArticleDOI
Current profile measurements with motional Stark effect polarimeter in the JT-60U tokamak
TL;DR: In this article, a motional Stark effect polarimeter with five viewing points has been installed to obtain current profiles in the JT-60U tokamak, and the inversion radius of the sawtooth oscillation agreed with the theoretical value (unity) within 10%.
Journal ArticleDOI
Observation of the limiter H mode in the JT-60 tokamak with lower-hybrid current drive
Shunji Tsuji,Kenkichi Ushigusa,Y. Ikeda,Tsuyoshi Imai,Itami T,M. Nemoto,Keisuke Nagashima,Yoshihiko Koide,Yasunori Kawano,T. Fukuda,Takashi Kondoh,M. Shimada,Haruki Nakamura,O. Naito,H. Yoshida,Takeo Nishitani,Hirotaka Kubo,Kenji Tobita,Y. Kusama,S. Ishida,Masayasu Sato,N. Isei,Tatsuo Sugie,Naoyuki Miya,Ryuji Yoshino,Kazuya Uehara +25 more
TL;DR: A nearly steady-state edge-localized-mode-free {ital H} mode with a duration up to 3.3 sec was established without significant impurity accumulation in limiter discharges of a tokamak with lower-hybrid current drive for the first time.
Journal ArticleDOI
Long sustainment of quasi-steady-state high βp H mode discharges in JT-60U
Akihiko Isayama,Yutaka Kamada,T. Ozeki,Shunsuke Ide,Toshiro Fujita,T. Oikawa,T. Suzuki,Yuzuru Neyatani,N. Isei,Kiyotaka Hamamatsu,Y. Ikeda,Koji Takahashi,K. Kajiwara,Jt Team +13 more
TL;DR: In this article, a quasi-steady state high βp H mode discharges performed by suppressing neoclassical tearing modes (NTMs) are described, and two operational scenarios have been developed for long sustainment of the high β p H mode discharge: NTM suppression by profile optimization, and NTM stabilization by local electron cyclotron current drive (ECCD)/electron cyclogron heating (ECH) at the magnetic island.