Large Helical Device (LHD) program

Fujiwara, Masami; Yamazaki, K.; Okamoto, Masayuki; Todoroki, Jiro; Amano, Tsuneo; Watanabe, Toshiya; Hayashi, T.; Sanuki, H.; Nakajima, N.; Itoh, K.; Sugama, H.; Ichiguchi, K.; Murakami, S.; Motojima, O.; Yamamoto, Junya; Satow, T.; Yanagi, N.; Imagawa, S.; Takahata, K.; Tamura, H.; Nishimura, A.; Komori, A.; Inoue, Noriyuki; Noda, N.; Sagara, A.; Kubota, Yoshinobu; Akaishi, N.; Satoh, Shuichi; Tanahashi, S.; Chikaraishi, H.; Mito, T.; Yamada, S.; Yamaguchi, S.; Sudo, S.; Sato, K.; Watari, T.; Kuroda, T.; Kaneko, O.; Ohkubo, Κ.; Kitagawa, S.; Andõ, Akira; Idei, H.; Tsumori, K.; Kubo, S.; Kumazawa, R.; Mutoh, T.; Oka, Y.; Sato, Masahiko; Seki, T.; Shimozuma, T.; Takeiri, Y.; Hamada, Y.; Narihara, K.; Kawahata, K.; Fujisawa, Shunsuke; Hidekuma, S.; Minami, Takashi; Yamada, I.; Ejiri, A.; Tanaka, K.; Sasao, M.; Iguchi, H.; Watanabe, K. Y.; Yamada, H.; Ohyabu, N.; Suzuki, H.; Iiyoshi, A.

doi:10.1007/bf02266926

Cited by 66 publications

(5 citation statements)

References 140 publications

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“…Experiments were carried out on Large Helical Device (LHD), a heliotron type magnetic confinement device with super conducting coils [5,6]. The major radius, averaged minor radius, magnetic field and plasma volume are 3.9 m, 0.6 m, 2.9 T and 30 m 3 , respectively.…”

Section: Experimental Set-upmentioning

confidence: 99%

Impact of pellet injection on extension of the operational region in LHD

et al. 2001

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Pellet injection has been used as a primary fueling scheme in Large Helical Device (LHD). Pellet injection has extended an operational region of NBI plasmas to higher densities with maintaining preferable dependence of energy confinement on density, and achieved several important data, such as plasma stored energy (0.88 MJ), energy confinement time (0.3 s), β (2.4 % at 1.3 T) and density (1.1×10 20 m-3). These parameters cannot be attained by gas puffing. Ablation and subsequent behavior of plasma has been investigated. Measured pellet penetration depth that is estimated by duration of the Hα emission is shallower than predicted penetration depth from the simple neutral gas shielding (NGS) model. The penetration depth can be explained by NGS model with fast ion effect on the ablation. Just after ablation, redistribution of ablated pellet mass was observed in short time (~ 400 µs). The redistribution causes shallow deposition and low fueling efficiency.

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Section: Experimental Set-upmentioning

confidence: 99%

Impact of pellet injection on extension of the operational region in LHD

et al. 2001

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“…With mm, MPa, and mm, (1) shows to be 45 N/m. On the other hand, the maximum electromagnetic force applied to a strand is about 300 N/m in the case of poloidal field coils for Large Helical Device [4]. It is difficult to apply the force equivalent to the electromagnetic field.…”

Section: B Compressive Loadmentioning

confidence: 99%

Strand movements in cable-in-conduit conductors

Takahata

Satow

2002

IEEE Trans. Appl. Supercond.

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Abstract-The compression tests with dummy bundles have been performed to investigate the strand movements in cable-in-conduit conductors. The bundle consists of 20 mm long vinyl tubes. The cross section of the bundle is a round-cornered rectangle of 10 mm 20 mm. Body force was applied in the transverse direction by means of a pressurized argon gas flow at room temperature. Pressure gradient in the bundle produced body force acting on each strand. The strand movements were observed with a CCD camera. Surface pressure was also applied with a piston, and a comparison has been made between two methods. Influence of a sub-bundle structure on the movements is also investigated.

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“…Negative ion sources with filament-arc discharge chambers have been developed for the JT-60U tokamak, 1,2) JT-60SA, 3,4) and the large Helical device (LHD). 5,6) Negative ions with high energy (>100 keV) have higher neutralisation efficiency in comparison with positive ions, 7,8) so that a negative ion-based neutral beam injector (NBI) has been intensively developed to penetrate the beam particles deep inside of the magnetically confined plasmas. To date, negative ion-based NBIs with filament-arc discharge systems have achieved sufficiently well-focused beams with beam divergences of 5 mrad on the JT-60U, 9) and 4.1 mrad and 6.1 mrad in the horizontal and the vertical directions, respectively, on the LHD.…”

Section: Introductionmentioning

confidence: 99%

Response of beam focusing to plasma fluctuation in a filament-arc-type negative ion source

Haba

Nagaoka

Tsumori

et al. 2020

Jpn. J. Appl. Phys.

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Beam focusing is one of the most important elements for the stable and safe operation of high power negative ion beams, such as neutral beam injection into magnetically confined fusion plasmas. In order to investigate impacts of the source plasma fluctuation on beam focusing, a simultaneous measurement of the source plasma fluctuation and the beam current profile has been carried out in the research-and-development negative ion source at the National Institute for Fusion Science. The responses of beam width and of the beam centre deviation are observed for the first time, indicating the importance of the source plasma stability for the negative ion beam focusing.

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Large Helical Device (LHD) program

Cited by 66 publications

References 140 publications

Impact of pellet injection on extension of the operational region in LHD

Impact of pellet injection on extension of the operational region in LHD

Strand movements in cable-in-conduit conductors

Response of beam focusing to plasma fluctuation in a filament-arc-type negative ion source

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