Control of the radial electric field shear by modification of the magnetic field configuration in LHD
Katsumi Ida,Mikiro Yoshinuma,Masayuki Yokoyama,Shigeru Inagaki,Naoki Tamura,Byron J. Peterson,Tomohiro Morisaki,Suguru Masuzaki,Akio Komori,Yoshio Nagayama,Kenji Tanaka,Kazumichi Narihara,K.Y. Watanabe,C. D. Beidler +13 more
TLDR
In this paper, the radial electric field profiles of the effective helical ripples are controlled by the modification of the magnetic field by changing the radial profile of the ripples,?h, creating a magnetic island with an external perturbation field coil and changing the local island divertor coil current.Abstract:
Control of the radial electric field, Er, is considered to be important in helical plasmas, because the radial electric field and its shear are expected to reduce neoclassical and anomalous transport, respectively. In general, the radial electric field can be controlled by changing the collisionality, and positive or negative electric fields have been obtained by decreasing or increasing the electron density, respectively. Although the sign of the radial electric field can be controlled by changing the collisionality, modification of the magnetic field is required to achieve further control of the radial electric field, especially to produce a strong radial electric field shear. In the Large Helical Device (LHD) the radial electric field profiles are shown to be controlled by the modification of the magnetic field by (1) changing the radial profile of the effective helical ripples, ?h, (2) creating a magnetic island with an external perturbation field coil and (3) changing the local island divertor coil current.read more
Citations
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Observation of an impurity hole in a plasma with an ion internal transport barrier in the Large Helical Device
Katsumi Ida,Mikiro Yoshinuma,Masaki Osakabe,K. Nagaoka,Masayuki Yokoyama,Hisamichi Funaba,Chihiro Suzuki,Takeshi Ido,Akihiro Shimizu,Izumi Murakami,Naoki Tamura,Hiroshi Kasahara,Yasuhiko Takeiri,Katsunori Ikeda,Katsuyoshi Tsumori,Osamu Kaneko,S. Morita,Motoshi Goto,Kenji Tanaka,Kazumichi Narihara,Takashi Minami,Ichihiro Yamada +21 more
TL;DR: Iiyoshi et al. as discussed by the authors evaluated the diffusion coefficient and convective velocity of impurities from the time evolution of carbon profiles assuming the diffusion and the convection velocity are constant in time after the formation of the internal transport barrier (ITB).
Journal ArticleDOI
Neoclassical plasma viscosity and transport processes in non-axisymmetric tori
TL;DR: In this article, an eight-moment approach to transport theory with plasma density N, plasma pressure p, mass flow velocity V and heat flow q as independent variables is adopted, emphasizing the pivotal role of the momentum equation in the transport processes and particularly useful in modelling plasma flows in experiments.
Journal ArticleDOI
On impurity handling in high performance stellarator/heliotron plasmas
R. Burhenn,Y. Feng,Katsumi Ida,H. Maassberg,Kieran J. McCarthy,D. V. Kalinina,Makoto I. Kobayashi,S. Morita,Y. Nakamura,H. Nozato,S. Okamura,S. Sudo,Chihiro Suzuki,Naoki Tamura,A. Weller,Mikiro Yoshinuma,B. Zurro +16 more
TL;DR: In this paper, the authors investigated the role of friction forces in the scrape-off-layer (SOL) and the generation of magnetic islands at the plasma boundary and to a certain degree also by edge localized modes, flushing out impurities and reducing the net impurity influx into the core.
Journal ArticleDOI
Experimental study of particle transport and density fluctuations in LHD
Kenji Tanaka,Clive Michael,Andrei Sanin,Leonid Vyacheslavov,Kazuo Kawahata,Sadayoshi Murakami,A. Wakasa,Shigeki Okajima,Hiroshi Yamada,Mamoru Shoji,J. Miyazawa,S. Morita,T. Tokuzawa,Tsuyoshi Akiyama,Motoshi Goto,Katsumi Ida,Mikiro Yoshinuma,Ichihiro Yamada,Masayuki Yokoyama,Suguru Masuzaki,Tomohiro Morisaki,Ryuichi Sakamoto,H. Funaba,Shigeru Inagaki,Makoto I. Kobayashi,A. Komori +25 more
TL;DR: In this article, the particle transport coefficients, i.e. diffusion coefficient (D) and convection velocity (V), were obtained in the standard configuration from density modulation experiments.
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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TL;DR: The structure of the edge radial electric field inferred from the poloidal rotation velocity is compared with that of the particle and thermal transport barrier for {ital H}-mode plasmas in JFT-2M and its gradient is found to become more negative at the {ital L}-{ital H] transition.
Edge electric field profiles of H-mode plasmas in JFT-2M tokamak
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Journal ArticleDOI
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TL;DR: The role of rational q surfaces in ITB triggering stresses the importance of q profile control for an advanced tokamak scenario and could assist in substantially lowering the access power to these scenarios in next step facilities as mentioned in this paper.
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