Journal ArticleDOI
Progress of High-Beta Experiments in Stellarator/Heliotron
Kiyomasa Watanabe,A. Weller,Satoru Sakakibara,Y. Narushima,S. Ohdachi,Kazumichi Narihara,Kenji Tanaka,Katsumi Ida,K. Toi,Hiroshi Yamada,Yasuhiro Suzuki,O. Kaneko +11 more
TLDR
In this article, the authors compared the LHD results with the Wendelstein 7-AS high-beta properties and showed the relationship between the experimentally achieved parameters and theoretical predictions.Abstract:
Recently, dramatic progress has been achieved in the study of helical systems with high-beta experiments. Discharges with more than 3% beta plasmas have been achieved in Large Helical Device (LHD) and Wendelstein 7-AS (W7-AS). Although magnetohydrodynamic (MHD) instabilities affect local pressure gradients, the global transport property does not seem to limit the achieved beta value in either device. We summarize the LHD high-beta properties in MHD stability, equilibrium, and transport, and we show the relationship between the experimentally achieved parameters and theoretical predictions. We contrast the LHD results with the W7-AS high-beta properties. In both devices, stationary discharges in the definitely MHD unstable region have not been observed. We mention the key issue for achievement of the beta values >5%.read more
Citations
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Journal ArticleDOI
Major results from the stellarator Wendelstein 7-AS (Review Article)
M. Hirsch,J. Baldzuhn,C. D. Beidler,R. Brakel,R. Burhenn,Andreas Dinklage,H. Ehmler,M. Endler,V. Erckmann,Y. Feng,J. Geiger,L. Giannone,G. Grieger,P. Grigull,H. J. Hartfuss,D. A. Hartmann,R. Jaenicke,R. König,H. P. Laqua,H. Maassberg,K. McCormick,F. Sardei,E. Speth,Ulrich Stroth,Friedrich E. Wagner,A. Weller,A. Werner,S. Zoletnik,W As Team +28 more
TL;DR: Wendelstein 7-AS was the first modular stellarator device to test some basic elements of stellarator optimization: a reduced Shafranov shift and improved stability properties resulted in β-values up to 3.4% as discussed by the authors.
Journal ArticleDOI
Development and application of HINT2 to helical system plasmas
TL;DR: In this paper, the three-dimensional (3D) magnetohydrodynamic (MHD) equilibrium solver HINT is improved as a new HINT code, 'HINT2' having various useful features by introducing modern computing techniques.
Journal ArticleDOI
Effects of global MHD instability on operational high beta-regime in LHD
K.Y. Watanabe,Satoru Sakakibara,Y. Narushima,H. Funaba,Kazumichi Narihara,K. A. Tanaka,T. Yamaguchi,K. Toi,Satoshi Ohdachi,Osamu Kaneko,Hiroshi Yamada,Yasuhiro Suzuki,W. A. Cooper,Sadayoshi Murakami,Noriyoshi Nakajima,Ichihiro Yamada,Kazuo Kawahata,T. Tokuzawa,A. Komori +18 more
TL;DR: In this paper, the effect of the global ideal MHD unstable mode on the operational regimes in helical systems, especially the beta gradients in the peripheral region and the beta value, are performed in a high-beta range of up to 4% in LHD.
Steepest descent moment method for three-dimensional magnetohydrodynamic equilibria
S. P. Hirshman,J. C. Whitson +1 more
TL;DR: In this article, an energy principle is used to obtain the solution of the magnetohydrodynamic (MHD) equilibrium equation J×B−∇p=0 for nested magnetic flux surfaces that are expressed in the inverse coordinate representation x=x(ρ, ρ, π, σ, ω, φ, υ, τ, ϵ, ϳ, ς, ψ, ϩ, ϸ, ϴ, Ϡ, ϖ, ϓ, ό, ϐ, Ϻ, ϔ
Journal ArticleDOI
Overview of confinement and MHD stability in the Large Helical Device
O. Motojima,Katsumi Ida,K.Y. Watanabe,Y. Nagayama,A. Komori,Tomohiro Morisaki,B.J. Peterson,Y. Takeiri,Kunizo Ohkubo,Kenji Tanaka,Takashi Shimozuma,Shigeru Inagaki,T. Kobuchi,Satoru Sakakibara,J. Miyazawa,Hiroshi Yamada,Nobuyoshi Ohyabu,K. Narihara,K. Nishimura,Mikiro Yoshinuma,S. Morita,Tsuyoshi Akiyama,N. Ashikawa,C. D. Beidler,M. Emoto,Takaaki Fujita,T. Fukuda,H. Funaba,P. R. Goncharov,Motoshi Goto,T. Ido,Katsunori Ikeda,Akihiko Isayama,Mitsutaka Isobe,Hiroe Igami,K. Ishii,Kimitaka Itoh,Osamu Kaneko,Kazuo Kawahata,H. Kawazome,Shin Kubo,Ryuhei Kumazawa,Suguru Masuzaki,K. Matsuoka,T. Minami,Sadayoshi Murakami,Sadatsugu Muto,Takashi Mutoh,Y. Nakamura,Hideya Nakanishi,Y. Narushima,Masaki Nishiura,A. Nishizawa,N. Noda,Takashi Notake,H. Nozato,Satoshi Ohdachi,Yoshihide Oka,Shigeki Okajima,Masaki Osakabe,T. Ozaki,Akio Sagara,T. Saida,K. Saito,Mizuki Sakamoto,Ryuichi Sakamoto,Yoshiteru Sakamoto,Mamiko Sasao,Kuninori Sato,Masahide Sato,Tetsuo Seki,Mamoru Shoji,S. Sudo,N. Takeuchi,Hidenobu Takenaga,Naoki Tamura,K. Toi,T. Tokuzawa,Yuki Torii,Katsuyoshi Tsumori,T. Uda,A. Wakasa,T. Watari,Ichihiro Yamada,Satoshi Yamamoto,K. Yamazaki,Masayuki Yokoyama,Yasuo Yoshimura +87 more
TL;DR: The Large Helical Device (LHD) as mentioned in this paper is a heliotron device with L = 2 and M = 10 continuous helical coils with a major radius of 3.5-4.1 m, a minor radius of 0.6 m and a toroidal magnetic confinement system for a steady state thermonuclear fusion reactor.
References
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Journal ArticleDOI
Steepest‐descent moment method for three‐dimensional magnetohydrodynamic equilibria
S. P. Hirshman,J. C. Whitson +1 more
TL;DR: In this article, an energy principle is used to obtain the solution of the magnetohydrodynamic (MHD) equilibrium equation J×B−∇p=0 for nested magnetic flux surfaces that are expressed in the inverse coordinate representation x=x(ρ, ρ, π, σ, ω, φ, υ, τ, ϵ, ϳ, ς, ψ, ϩ, ϸ, ϴ, Ϡ, ϖ, ϓ, ό, ϐ, Ϻ, ϔ
Journal ArticleDOI
Density limits in toroidal plasmas
TL;DR: In addition to the operational limits imposed by MHD stability on plasma current and pressure, an independent limit on plasma density is observed in confined toroidal plasmas as mentioned in this paper, where all toroidal confinement devices considered operate in similar ranges of (suitably normalized) densities.
Journal ArticleDOI
Energy confinement scaling from the international stellarator database
TL;DR: An international stellarator database on global energy confinement is presented in this article, which comprises a total of 859 discharges from the ATF, CHS and Heliotron-E heliotron/torsatrons and the W7-A and W7 -AS shearless stellarators.
Journal ArticleDOI
Overview of the large helical device project
A. Iiyoshi,Akio Komori,Akira Ejiri,Masahiko Emoto,Hisamichi Funaba,Motoshi Goto,Katsumi Ida,Hiroshi Idei,Shigeru Inagaki,Shinichiro Kado,Osamu Kaneko,Kazuo Kawahata,T. Kobuchi,Shin Kubo,Ryuhei Kumazawa,Suguru Masuzaki,T. Minami,J. Miyazawa,Tomohiro Morisaki,S. Morita,S. Murakami,Sadatsugu Muto,Takashi Mutoh,Yoshio Nagayama,Y. Nakamura,Hideya Nakanishi,K. Narihara,K. Nishimura,N. Noda,Satoshi Ohdachi,Nobuyoshi Ohyabu,Yoshihide Oka,Masaki Osakabe,T. Ozaki,B.J. Peterson,Akio Sagara,Satoru Sakakibara,Ryuichi Sakamoto,H. Sasao,Mamiko Sasao,Kuninori Sato,Masahide Sato,Tetsuo Seki,Takashi Shimozuma,Mamoru Shoji,Hajime Suzuki,Y. Takeiri,Kenji Tanaka,K. Toi,T. Tokuzawa,Katsuyoshi Tsumori,Kazuhiro Tsuzuki,K.Y. Watanabe,T. Watari,Hiroshi Yamada,Ichihiro Yamada,Soichiro Yamaguchi,Masayuki Yokoyama,R. Akiyama,Hirotaka Chikaraishi,K. Haba,Shinji Hamaguchi,M. Iima,Shinsaku Imagawa,N. Inoue,K. Iwamoto,S. Kitagawa,J. Kodaira,Yuusuke Kubota,Ryuji Maekawa,Toshiyuki Mito,Takuya Nagasaka,Arata Nishimura,C. Takahashi,Kazuya Takahata,Y. Takita,Hitoshi Tamura,T. Tsuzuki,S. Yamada,Kenji Yamauchi,Nagato Yanagi,H. Yonezu,Y. Hamada,Ken Matsuoka,K. Murai,Kunizo Ohkubo,I. Ohtake,M. Okamoto,Sadao Satoh,Takashi Satow,S. Sudo,S. Tanahashi,K. Yamazaki,Masami Fujiwara,O. Motojima +94 more
TL;DR: The Large Helical Device (LHD) has successfully started running plasma confinement experiments after a long construction period of eight years as mentioned in this paper, and the first plasma was ignited on 31 March 1998.
Journal ArticleDOI
Scalings of energy confinement and density limit in stellarator/heliotron devices
TL;DR: In this article, the authors presented a study of empirical scaling of energy confinement observed experimentally in stellarator/heliotron devices (Heliotron E, Wendelstein VII-A, L2, Heliotron DR) for plasmas heated by electron cyclotron heating and neutral beam injection.
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