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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:74.03(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:45.73(Nuclear Science & Technology)

Journal Articles

In-vessel coils for magnetic error field correction in JT-60SA

Matsunaga, Go; Takechi, Manabu; Sakurai, Shinji; Suzuki, Yasuhiro*; Ide, Shunsuke; Urano, Hajime

Fusion Engineering and Design, 98-99, p.1113 - 1117, 2015/10

 Times Cited Count:9 Percentile:24.34(Nuclear Science & Technology)

Journal Articles

Estimation of the lifetime of resin insulators against baking temperature for JT-60SA in-vessel coils

Sukegawa, Atsuhiko; Murakami, Haruyuki; Matsunaga, Go; Sakurai, Shinji; Takechi, Manabu; Yoshida, Kiyoshi; Ikeda, Yoshitaka

Fusion Engineering and Design, 98-99, p.2076 - 2079, 2015/10

 Times Cited Count:1 Percentile:86.11(Nuclear Science & Technology)

The JT-60SA project is a EU - JA satellite tokamak under Broader Approach in support of the ITER project. In-vessel coils are designed and assembled by JA. The resin-insulator is required to have a heat resistance against the baking temperature of vacuum vessel of $$sim$$200$$^{circ}$$C (40000 hour). Thus the assessment of the heat load is fundamental for the design of the coils. However, the estimation of the lifetime of resin-insulator under the high-temperature region has not been examined. In the present study, the estimation of the lifetime of seven candidate resin-insulators such as epoxy resin and cyanate-ester resin under the $$sim$$220$$^{circ}$$C temperature region have been performed for the current coils design. Weight reduction of the seven candidate insulators was measured at different heating times under 180$$^{circ}$$C, 200$$^{circ}$$C and 220$$^{circ}$$C environment using three thermostatic ovens, respectively. The reduction of the insulators has been used as input for Weibull-analysis towards Arrhenius-plot. Lifetime of the resins has been estimated for the first time at the high temperature region by the plot. Lifetime of the resin-insulators have been evaluated and discussed as well as the available temperature of the in-vessel coils.

Journal Articles

Assessment of the accuracy of plasma shape reconstruction by the Cauchy condition surface method in JT-60SA

Miyata, Yoshiaki; Suzuki, Takahiro; Takechi, Manabu; Urano, Hajime; Ide, Shunsuke

Review of Scientific Instruments, 86(7), p.073511_1 - 073511_13, 2015/07

 Times Cited Count:3 Percentile:78.36(Instruments & Instrumentation)

It is essential for a stable plasma equilibrium control to reconstruct an accurate plasma boundary in tokamak devices. Cauchy Condition Surface (CCS) method is a numerical approach to calculate the spatial distribution of the magnetic flux outside a hypothetical plasma surface and reconstruct the plasma boundary from the magnetic measurements located outside the plasma. It is found that the optimum number of unknown parameters and shape of the CCS for minimizing errors in the reconstructed plasma shape increase in proportion to the plasma size. It is shown that the accuracy of the plasma shape reconstruction greatly improves by using the optimum number of unknown parameters. The assessment of accuracy of plasma shape reconstruction by CCS method in JT-60SA is reported.

Journal Articles

Optimization of JT-60SA plasma operational scenario with capabilities of installed actuators

Ide, Shunsuke; Aiba, Nobuyuki; Bolzonella, T.*; Challis, C. D.*; Fujita, Takaaki; Giruzzi, G.*; Joffrin, E.*; Hamamatsu, Kiyotaka; Hayashi, Nobuhiko; Honda, Mitsuru; et al.

Proceedings of 24th IAEA Fusion Energy Conference (FEC 2012) (CD-ROM), 8 Pages, 2013/03

Journal Articles

Effects of perturbed magnetic field on the control of macroscopic instability

Takechi, Manabu

Purazuma, Kaku Yugo Gakkai-Shi, 88(3), p.162 - 167, 2012/03

no abstracts in English

Journal Articles

Electromagnetic analyses on radial field sector coils for JT-60SA

Ferro, A.*; Gaio, E.*; Takechi, Manabu; Matsukawa, Makoto

Fusion Engineering and Design, 86(6-8), p.1527 - 1530, 2011/10

 Times Cited Count:2 Percentile:78.02(Nuclear Science & Technology)

In JT-60SA, to achieve the steady-state high beta plasma, suppression of Resistive Wall Modes (RWM) is necessary. Therefore, a passive stabilizing plate and a RWM active control system based on in-vessel coils are foreseen for JT-60SA. This paper deals with the electromagnetic analyses on the sector coils of JT-60SA, with the main aim to determine the voltage/current characteristic of the coils and, at the same time, to have a first estimation of amplitude and shape of the produced magnetic field; different sector coil design solutions were considered and evaluated. The studies on the coil over-currents during plasma disruption or vertical displacement events are also presented. The results give useful indications in support to the development of the sector coils and power supply design and the identification of their electrical and functional requirements.

Journal Articles

Core transport properties in JT-60U and JET identity plasmas

Litaudon, X.*; Sakamoto, Yoshiteru; de Vries, P. C.*; Salmi, A.*; Tala, T.*; Angioni, C.*; Benkadda, S.*; Beurskens, M. N. A.*; Bourdelle, C.*; Brix, M.*; et al.

Nuclear Fusion, 51(7), p.073020_1 - 073020_13, 2011/07

 Times Cited Count:8 Percentile:63.81(Physics, Fluids & Plasmas)

A variety of triggering mechanisms and structures of internal transport barrier (ITB) has been observed in various devices or depending on operation scenarios. Thus identity experiments on ITB in JT-60U and JET have been performed to shed light on the physics behind ITBs. Because of their similar size, the dimensionless parameters between both devices are the same. These experiments were performed with near identical magnetic configurations, heating waveforms and normalized quantities such as safety factor, magnetic shear, normalized Larmor radius, normalized collision frequency, beta, temperatures ratio. Similarities of the ITB triggering mechanism and the ITB strength have been observed when a proper match is achieved of the most relevant profiles of the normalized quantities. This paper will report on the detail comparison of transport properties of ITBs obtained in these JET/JT-60U identity experiments.

Journal Articles

Interactions between MHD instabilities in the wall-stabilized high-$$beta$$ plasmas

Matsunaga, Go; Aiba, Nobuyuki; Shinohara, Koji; Sakamoto, Yoshiteru; Takechi, Manabu; Suzuki, Takahiro; Asakura, Nobuyuki; Isayama, Akihiko; Oyama, Naoyuki; Yoshida, Maiko; et al.

Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 8 Pages, 2011/03

Journal Articles

Overcurrent analyses in JT-60SA poloidal circuits due to plasma disruption and quench protection intervention

Novello, L.*; Gaio, E.*; Piovan, R.*; Takechi, Manabu; Ide, Shunsuke; Matsukawa, Makoto

Fusion Engineering and Design, 86(1), p.33 - 40, 2011/01

 Times Cited Count:9 Percentile:34.74(Nuclear Science & Technology)

JAEA Reports

Conceptual design of the SlimCS fusion DEMO reactor

Tobita, Kenji; Nishio, Satoshi*; Enoeda, Mikio; Nakamura, Hirofumi; Hayashi, Takumi; Asakura, Nobuyuki; Uto, Hiroyasu; Tanigawa, Hiroyasu; Nishitani, Takeo; Isono, Takaaki; et al.

JAEA-Research 2010-019, 194 Pages, 2010/08

JAEA-Research-2010-019-01.pdf:48.47MB
JAEA-Research-2010-019-02.pdf:19.4MB

This report describes the results of the conceptual design study of the SlimCS fusion DEMO reactor aiming at demonstrating fusion power production in a plant scale and allowing to assess the economic prospects of a fusion power plant. The design study has focused on a compact and low aspect ratio tokamak reactor concept with a reduced-sized central solenoid, which is novel compared with previous tokamak reactor concept such as SSTR (Steady State Tokamak Reactor). The reactor has the main parameters of a major radius of 5.5 m, aspect ratio of 2.6, elongation of 2.0, normalized beta of 4.3, fusion out put of 2.95 GW and average neutron wall load of 3 MW/m$$^{2}$$. This report covers various aspects of design study including systemic design, physics design, torus configuration, blanket, superconducting magnet, maintenance and building, which were carried out increase the engineering feasibility of the concept.

Journal Articles

Energetic particle driven instability in wall-stabilized high-$$beta$$ plasmas

Matsunaga, Go; Shinohara, Koji; Aiba, Nobuyuki; Sakamoto, Yoshiteru; Isayama, Akihiko; Asakura, Nobuyuki; Suzuki, Takahiro; Takechi, Manabu; Oyama, Naoyuki; Urano, Hajime; et al.

Nuclear Fusion, 50(8), p.084003_1 - 084003_8, 2010/08

 Times Cited Count:26 Percentile:23.75(Physics, Fluids & Plasmas)

Journal Articles

Mode rigidity study of RWM on RFX with reduced RWM control coils for JT-60SA RWM stabilization

Takechi, Manabu; Bolzonella, T.*; Baruzzo, M.*; Ide, Shunsuke; Matsunaga, Go; JT-60SA Team

Europhysics Conference Abstracts (Internet), 34A, p.P2.192_1 - P2.192_4, 2010/00

Journal Articles

Rotational stabilization of resistive wall mode on JT-60U

Matsunaga, Go; Takechi, Manabu; Aiba, Nobuyuki; Kurita, Genichi; Sakamoto, Yoshiteru; Koide, Yoshihiko; Isayama, Akihiko; Suzuki, Takahiro; Fujita, Takaaki; Oyama, Naoyuki; et al.

Plasma and Fusion Research (Internet), 4, p.051_1 - 051_7, 2009/11

no abstracts in English

Journal Articles

Development of reversed shear plasmas with high bootstrap current fraction towards reactor relevant regime in JT-60U

Sakamoto, Yoshiteru; Matsunaga, Go; Oyama, Naoyuki; Suzuki, Takahiro; Aiba, Nobuyuki; Takenaga, Hidenobu; Isayama, Akihiko; Shinohara, Koji; Yoshida, Maiko; Takechi, Manabu; et al.

Nuclear Fusion, 49(9), p.095017_1 - 095017_8, 2009/09

 Times Cited Count:23 Percentile:30.63(Physics, Fluids & Plasmas)

This paper reports the recent development of reversed shear plasmas with a high bootstrap current fraction towards reactor relevant regime, especially lower $$q$$$$_{95}$$ regime. By utilizing large volume configuration close to the conductive wall for wall stabilization, the beta limit of the reversed shear plasmas is significantly improved. As a result, high confinement reversed shear plasmas with high bootstrap current fraction exceeding no-wall beta limit are obtained in reactor relevant regime, where $$beta$$$$_{rm N}$$ of 2.7, $$beta$$$$_{rm P}$$ of 2.3 is achieved with reversed $$q$$ profile with $$q$$$$_{rm min}$$ of 2.3, and then HH$$_{rm 98y2}$$ of 1.7, $$n$$$$_{rm e}$$/$$n$$$$_{rm GW}$$ of 0.87 and $$f$$$$_{rm BS}$$ of 0.9 are also obtained at $$q$$$$_{95}$$ of 5.3.

Journal Articles

Plasma rotation effects on magnetic island formation and the trigger of disruptions in reversed shear plasma

Ishii, Yasutomo; Smolyakov, A. I.*; Takechi, Manabu

Nuclear Fusion, 49(8), p.085006_1 - 085006_10, 2009/08

 Times Cited Count:21 Percentile:33.71(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Observation of an energetic-particle-driven instability in the wall-stabilized high-$$beta$$ plasmas in the JT-60U tokamak

Matsunaga, Go; Aiba, Nobuyuki; Shinohara, Koji; Sakamoto, Yoshiteru; Isayama, Akihiko; Takechi, Manabu; Suzuki, Takahiro; Oyama, Naoyuki; Asakura, Nobuyuki; Kamada, Yutaka; et al.

Physical Review Letters, 103(4), p.045001_1 - 045001_4, 2009/07

 Times Cited Count:39 Percentile:14.6(Physics, Multidisciplinary)

Journal Articles

Mock-up test results of monoblock-type CFC divertor armor for JT-60SA

Higashijima, Satoru; Sakurai, Shinji; Suzuki, Satoshi; Yokoyama, Kenji; Kashiwa, Yoshitoshi; Masaki, Kei; Shibama, Yusuke; Takechi, Manabu; Shibanuma, Kiyoshi; Sakasai, Akira; et al.

Fusion Engineering and Design, 84(2-6), p.949 - 952, 2009/06

 Times Cited Count:8 Percentile:45.11(Nuclear Science & Technology)

An upgrading device of JT-60 tokamak with fully superconducting coils (JT-60SA) is constructed under both the Japanese domestic program and the international program "Broader Approach". The maximum heat flux to JT-60SA divertor is estimated to 15 MW/m$$^{2}$$ for 100 s, and a monoblock-type CFC divertor armor is promising. The JT-60SA armor consists of CFC monoblocks, a cooling CuCrZr screw-tube, and a thin OFHC-Cu buffer layer, and the brazed joints are essential for the armor. Metalization inside CFC monoblock is applied for further improvement, and we confirmed again that the mock-up has heat removal capability in excess of ITER requirement. For optimization of the fabrication method and understanding of the production yield, the mock-ups corresponding to quantity produced in one furnace is also produced, and the half of the mock-ups could remove 15 MW/m$$^{2}$$ as required. This summarizes the recent progress of design and mock-up test results for JT-60SA divertor armor.

Journal Articles

An Enemy of high-beta plasma; Resistive wall mode

Takechi, Manabu; Matsunaga, Go; Shiraishi, Junya; Tokuda, Shinji; Tobita, Kenji

Purazuma, Kaku Yugo Gakkai-Shi, 85(4), p.147 - 162, 2009/04

no abstracts in English

139 (Records 1-20 displayed on this page)