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Journal Articles

Reference design of the power supply system for the resistive-wall-mode control in JT-60SA

Ferro, A.*; Gaio, E.*; Novello, L.*; Matsukawa, Makoto; Shimada, Katsuhiro; Kawamata, Yoichi; Takechi, Manabu

Fusion Engineering and Design, 98-99, p.1053 - 1057, 2015/10

 Times Cited Count:2 Percentile:74.39(Nuclear Science & Technology)

Journal Articles

Development of magnetic sensors for JT-60SA

Takechi, Manabu; Matsunaga, Go; Sakurai, Shinji; Sasajima, Tadayuki; Yagyu, Junichi; Hoshi, Ryo*; Kawamata, Yoichi; Kurihara, Kenichi; JT-60SA Team; Nishikawa, T.*; et al.

Fusion Engineering and Design, 96-97, p.985 - 988, 2015/10

 Times Cited Count:5 Percentile:46.24(Nuclear Science & Technology)

Journal Articles

Eddy current-adjusted plasma shape reconstruction by Cauchy condition surface method on QUEST

Nakamura, Kazuo*; Jiang, Y.*; Liu, X.*; Mitarai, Osamu*; Kurihara, Kenichi; Kawamata, Yoichi; Sueoka, Michiharu; Hasegawa, Makoto*; Tokunaga, Kazutoshi*; Zushi, Hideki*; et al.

Fusion Engineering and Design, 86(6-8), p.1080 - 1084, 2011/10

 Times Cited Count:4 Percentile:61.89(Nuclear Science & Technology)

Journal Articles

Architecture plan of the real-time diagnostic signals acquisition system toward JT-60SA project

Sakata, Shinya; Yamaguchi, Taiji; Sugimura, Toru; Kominato, Toshiharu; Kawamata, Yoichi; Totsuka, Toshiyuki; Sato, Minoru; Sueoka, Michiharu; Naito, Osamu

Fusion Science and Technology, 60(2), p.496 - 500, 2011/08

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

For a steady state operation of JT-60SA, a plasma feedback control using various diagnostic sensor signals plays an essential role. To realize this, Real Time Diagnostic Signals acquisition System, RTDS, which utilizes PC-based real-time OS "INtime", has been under consideration toward JT-60SA project. Moreover, long-time experiments more than 100 seconds will be planned in JT-60SA project. Therefore, real time monitoring will be required as an essential function that displays acquired diagnostic signals on real time during long-time experiment. This function will be also realized by utilizing RTDS.

Journal Articles

Development of PC-based control system in JT-60SA

Kawamata, Yoichi; Sugimura, Toru; Yamaguchi, Taiji; Sueoka, Michiharu; Sakata, Shinya; Totsuka, Toshiyuki; Sato, Minoru; Kominato, Toshiharu; Naito, Osamu

Fusion Science and Technology, 60(2), p.491 - 495, 2011/08

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

Journal Articles

Vacuum brazing of the new RFQ for the J-PARC linac

Morishita, Takatoshi; Kondo, Yasuhiro; Hasegawa, Kazuo; Naito, Fujio*; Yoshioka, Masakazu*; Matsumoto, Hiroshi*; Hori, Yoichiro*; Kawamata, Hiroshi*; Saito, Yoshio*; Baba, Hiroshi*

Proceedings of 25th International Linear Accelerator Conference (LINAC 2010) (CD-ROM), p.521 - 523, 2010/09

The fabrication of a new RFQ has been started as a backup machine for the J-PARC linac. The RFQ cavity is divided by three unit tanks in the longitudinal direction. The unit tank consists of two major vanes and two minor vanes, those are brazed together. A one-step vacuum brazing of a unit tank was adopted to unite these four vanes together with the flanges and ports. At the first tank brazing, the vacuum leak has been occurred due to the non-uniform temperature rise during the heating. Repair of this leakage and the results of the improved brazing of the second tank are reported.

Journal Articles

Vane machining by the ball-end-mill for the new RFQ in the J-PARC linac

Morishita, Takatoshi; Kondo, Yasuhiro; Hasegawa, Kazuo; Kawamata, Hiroshi*; Naito, Fujio*; Yoshioka, Masakazu*; Matsumoto, Hiroshi*; Hori, Yoichiro*; Saito, Yoshio*; Baba, Hiroshi*

Proceedings of 25th International Linear Accelerator Conference (LINAC 2010) (CD-ROM), p.518 - 520, 2010/09

The fabrication of a new RFQ has been started in the J-PARC linac. The RFQ cavity is divided by three unit tanks in the longitudinal direction. The unit tank consists of two major vanes and two minor vanes, those will be brazed together. To reduce the costs and periods to develop the special formed bite for the modulation machining, a numerical controlled machining using a conventional ball-end-mill was adopted for the vane modulation cutting instead of the wheel shape cutter. The dimension accuracy was confirmed by cutting test pieces. Moreover, the obtained surface seems smooth enough for the operation. Results of the ball-end-mill machining for the vanes are described.

Journal Articles

Fabrication of the new RFQ for the J-PARC linac

Morishita, Takatoshi; Kondo, Yasuhiro; Hasegawa, Kazuo; Naito, Fujio*; Yoshioka, Masakazu*; Matsumoto, Hiroshi*; Hori, Yoichiro*; Kawamata, Hiroshi*; Saito, Yoshio*; Baba, Hiroshi*

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.783 - 785, 2010/05

The J-PARC RFQ (length 3.1 m, 4-vane type, 324 MHz) accelerates a negative hydrogen beam from 0.05 MeV to 3 MeV toward the following DTL. The stability of the operating RFQ decreased for a few months at the end of 2008, then, we started a preparation of a new RFQ as a backup machine in the case of RFQ problem. The beam dynamics design of the new RFQ is the same as the current cavity for a quick resumption of operation, however, the engineering and RF designs are changed to improve stability. The processes of the vane machining and the surface treatments have been carefully considered to reduce the discharge problem. The vacuum brazing technique has been chosen for vane jointing. The design of the new RFQ and the fabrication progress is descried in this proceeding.

Journal Articles

Engineering design of RFQ at J-PARC linac

Morishita, Takatoshi; Kondo, Yasuhiro; Hasegawa, Kazuo; Naito, Fujio*; Yoshioka, Masakazu*; Matsumoto, Hiroshi*; Hori, Yoichiro*; Kawamata, Hiroshi*; Saito, Yoshio*; Baba, Hiroshi*; et al.

Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.1047 - 1049, 2010/03

The beam commissioning of J-PARC linac has been started since November 2006. After the scheduled shutdown in summer 2007, the beam is successfully delivered from the linac to the RCS. Since then, a stable beam provision was emphasized. However, the trip in the RFQ was increased at the end of Sept. 2008, then, the stability of the beam operation decreased. To improve this situation, we started to prepare a new RFQ cavity as a backup machine. The basic concept of the engineering design is the simplicity and the effective vacuum pumping aiming at the stable operation. A 3m long cavity is divided into 3 modules longitudinally. A numerical control machining with ball-end mill is chosen for a vane machining. Four vanes are vacuum brazed each other after machining. Each modules are aligned on the platform using a linear motion guide. A basic design of the key components on machining and brazing are described in this proceeding.

Journal Articles

Status of the J-PARC RFQ

Hasegawa, Kazuo; Morishita, Takatoshi; Kondo, Yasuhiro; Oguri, Hidetomo; Kobayashi, Tetsuya; Naito, Fujio*; Yoshioka, Masakazu*; Matsumoto, Hiroshi*; Kawamata, Hiroshi*; Hori, Yoichiro*; et al.

Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.693 - 695, 2010/03

The J-PARC RFQ (length 3.1m, 4-vane type, 324 MHz) accelerates a beam from the ion source to the DTL. The beam test of the linac was started in November 2006 and 181 MeV beam was successfully accelerated in January 2007. Since then, the linac has been delivered beams for commissioning of the linac itself, downstream accelerators and facilities. Trip rates of the RFQ, however, suddenly increased in Autumn 2008, and we are suffering from this issue for user run operation. We tried to recover by tender conditioning, modification of RF control, improvement of vacuum and so on. We manage to have beam operation. In this report, we describe the status of the RFQ.

Journal Articles

Real-time measurement and feedback control of ion temperature profile and toroidal rotation using fast CXRS system in JT-60U

Yoshida, Maiko; Sakamoto, Yoshiteru; Sueoka, Michiharu; Kawamata, Yoichi; Oyama, Naoyuki; Suzuki, Takahiro; Kamada, Yutaka; JT-60 Team

Fusion Engineering and Design, 84(12), p.2206 - 2213, 2009/12

 Times Cited Count:11 Percentile:35.15(Nuclear Science & Technology)

A fast charge exchange recombination spectroscopy (CXRS) system has been developed for the real-time measurement and feedback control of ion temperature ($$T$$$$_{rm i}$$) profile and toroidal rotation velocity ($$V$$$$_{rm t}$$) in JT-60U. In order to control $$T$$$$_{rm i}$$ and $$V$$$$_{rm t}$$ in real-time, the charge exchange recombination spectroscopy with high time resolution, the real-time processor system, and the real-time control system have been developed. Utilizing this system, real-time control of the $$T$$$$_{rm i}$$ gradient has been demonstrated with neutral beams at high beta plasmas. The strength of the internal transport barrier is controlled. Moreover, the real-time control of $$V$$$$_{rm t}$$ has been demonstrated from counter (anti parallel to the plasma current, $$I$$$$_{rm p}$$) to co (parallel to the $$I$$$$_{rm p}$$) direction.

Journal Articles

Improvement of the real-time processor in JT-60 data processing system

Sakata, Shinya; Kiyono, Kimihiro; Sato, Minoru; Kominato, Toshiharu; Sueoka, Michiharu; Hosoyama, Hiroki; Kawamata, Yoichi

Fusion Engineering and Design, 84(7-11), p.1680 - 1683, 2009/06

 Times Cited Count:1 Percentile:88.61(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Application study of a plasma shape reproduction system based on the Cauchy-condition surface (CCS) method considering plasma real-time control

Kurihara, Kenichi; Kawamata, Yoichi; Sueoka, Michiharu; Wang, F.*; Nakamura, Kazuo*; Mitarai, Osamu*; Sato, Konosuke*; Zushi, Hideki*; Hanada, Kazuaki*; Sakamoto, Mizuki*; et al.

Kyushu Daigaku Oyo Rikigaku Kenkyujo RIAM Foramu 2008 Koen Yoshi, p.66 - 69, 2008/06

no abstracts in English

Journal Articles

Development of the supervisory discharge operation monitoring system for JT-60

Sueoka, Michiharu; Totsuka, Toshiyuki; Kawamata, Yoichi; Kurihara, Kenichi; Seki, Akiyuki

Fusion Engineering and Design, 83(2-3), p.283 - 286, 2008/04

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

For safety and efficient operation of a fusion device, appropriate information should be provided to the personnel related to experiment. In order to realize this, we have newly developed highlight screens displaying the plasma movie, the status of discharge sequence, the discharge schedule, the present status of trouble, etc., with the large (65 inch) monitor TV in front of the central consoles. These highlight screens are automatically switched according to the timing signal of JT-60 discharge sequence and/or the operator's request. We call this system the supervisory discharge operation monitoring system. This report deals with the technical details of this system including the plasma movie database system and the discharge information management system.

Journal Articles

Design study of the JT-60SA supervisory control system

Kawamata, Yoichi; Naito, Osamu; Kiyono, Kimihiro; Itami, Kiyoshi; Totsuka, Toshiyuki; Akasaka, Hiromi; Sueoka, Michiharu; Sato, Tomoki; Oshima, Takayuki; Sakata, Shinya; et al.

Fusion Engineering and Design, 83(2-3), p.198 - 201, 2008/04

 Times Cited Count:3 Percentile:73.37(Nuclear Science & Technology)

The design activity of JT-60SA (JT-60 Super Advanced) which is remodeled to a superconducting tokamak device has been starting under the JA-EU collaborative ITER-BA project. For the JT-60SA control system, the existing system should be reused as much as possible from the viewpoint of cost-effectiveness. We have just begun to discuss the configuration of the advanced Supervisory Control System (SVCS) including the following systems: (1) ultimately flexible real-time control system, (2) precise timing system enough to clarify cause and effect, and (3) safety shutdown control system. In this report, we present the design study of the JT-60SA SVCS with focusing on these systems.

JAEA Reports

Development of the plasma movie database system for JT-60

Sueoka, Michiharu; Kawamata, Yoichi; Kurihara, Kenichi; Seki, Akiyuki

JAEA-Technology 2008-021, 23 Pages, 2008/03

JAEA-Technology-2008-021.pdf:10.47MB

A plasma movie is generally expected as one of the most efficient methods to know what plasma discharge has been conducted in the experiment. The JT-60 plasma movie is composed of video camera picture looking at a plasma, computer graphics (CG) picture, and magnetic probe signal as a sound channel. In order to use this movie efficiently, we have developed a new system having the following functions: (a) To store a plasma movie in the movie database system automatically combined with the plasma shape CG and the sound according to a discharge sequence. (b) To make a plasma movie is available (downloadable) for experiment data analyses at the Web-site. Especially, this system aimed at minimizing the development cost, and it tried to develop the real-time plasma shape visualization system (RVS) without any operating system (OS) customized for real-time use. As a result, this system succeeded in working under Windows XP. This report deals with the technical details of the plasma movie database system and the real-time plasma shape visualization system.

Journal Articles

Response of fusion gain to density in burning plasma simulation on JT-60U

Takenaga, Hidenobu; Kubo, Hirotaka; Sueoka, Michiharu; Kawamata, Yoichi; Yoshida, Maiko; Kobayashi, Shinji*; Sakamoto, Yoshiteru; Iio, Shunji*; Shimomura, Koji*; Ichige, Hisashi; et al.

Nuclear Fusion, 48(3), p.035011_1 - 035011_6, 2008/03

 Times Cited Count:2 Percentile:89.8(Physics, Fluids & Plasmas)

A burning plasma simulation scheme has been developed with consideration for temperature dependence of the DT fusion reaction rate in JT-60U. The heating power for the simulation of alpha particle heating was calculated using real-time measurements of density and ion temperature. Response of a simulated fusion gain to the density was investigated in this scheme with constant heating power for the simulation of external heating, in order to understand burn controllability by the fuel density in a fusion reactor. When temperature dependence of the fusion reaction rate was assumed as square of ion temperature, density dependence of the simulated fusion gain stronger than square of density was observed. Transport analysis using a 1.5 dimension transport code indicated that the strong density dependence is induced due to both change in a confinement improvement factor and change in a pressure profile.

Journal Articles

The Plasma movie database system for JT-60

Sueoka, Michiharu; Kawamata, Yoichi; Kurihara, Kenichi; Seki, Akiyuki

Fusion Engineering and Design, 82(5-14), p.1008 - 1014, 2007/10

 Times Cited Count:2 Percentile:79.6(Nuclear Science & Technology)

A plasma movie is generally expected as one of the most efficient methods to know what plasma discharge has been conducted in the experiment. On this motivation we have developed and operated a real-time plasma shape visualization system over ten years. The current plasma movie is composed of (1) video camera picture looking at a plasma, (2) computer graphic (CG) picture, and (3) magnetic probe signal as a sound channel. In order to use this movie efficiently, we have developed a new plasma movie database system, where a plasma movie is available (downloadable) for experiment data analyses at the Web-site. This new system and its future prospects will be discussed in detals from a technological point of view.

Journal Articles

Burn control simulation experiments in JT-60U

Shimomura, Koji*; Takenaga, Hidenobu; Tsutsui, Hiroaki*; Mimata, Hideyuki*; Iio, Shunji*; Miura, Yukitoshi; Tani, Keiji; Kubo, Hirotaka; Sakamoto, Yoshiteru; Hiratsuka, Hajime; et al.

Fusion Engineering and Design, 82(5-14), p.953 - 960, 2007/10

 Times Cited Count:2 Percentile:79.6(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Development of magnetic probe; Application and result of AT-probes to JT-60U (Joint research)

Yagyu, Junichi; Sasajima, Tadayuki; Miyo, Yasuhiko; Sakakibara, Satoru*; Kawamata, Yoichi

JAEA-Technology 2007-015, 27 Pages, 2007/03

JAEA-Technology-2007-015.pdf:2.94MB

The feedback control of the plasma position and shape based on signals of magnetic probes is performed on JT-60. The fabrication cost of these magnetic probes is very high. Therefore, the cost reduction is required for the use in a next device. On the other hand, the magnetic field measurement in three axial directions with the advanced technology (AT) probes is simultaneously made on LHD of NIFS. The AT-probe has been developed at a low fabrication cost and in compact size and light weight. The possibility of application of the AT-probe in a Tokamak device (JT-60U) has been investigated in collaboration between JAEA and NIFS. We designed and fabricated the casing and interface for the AT-probe, and installed it under the first wall of JT-60U. A comparison of output signals between the installed AT-probe and a existing magnetic probe was made. Tests have been carried out to evaluate the vibration resistance and the radioactive resistance through about two thousand shots with high performance plasmas including one hundred disruption shots in JT-60U. As a result, the AT-probe has a good performance and an enough usable prospect in environment of the Tokamak device.

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