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Ishii, Yasutomo; Matsunaga, Go; Okumura, Yoshikazu
Purazuma, Kaku Yugo Gakkai-Shi, 91(4), p.296 - 297, 2015/04
Holding of the IFMIF/EVEDA Project Committee, IFERC Project Committee and IFERC-CSC Workshop and progress of the JT-60SA were reported. For the 15th IFMIF/EVEDA-PC, 31 were present and they discussed project plan etc. and concluded technical advice to the BA Steering Committee. For the 16th IFERC-PC, 32 were present and they discussed the 2014 annual report and revision of project plan and concluded technical advice to the BA-SC. For the IFERC-CSC Workshop, 39 Domestic Researcher were attended and they reported the result of each project and exchanged views in utilizing CSC. In the JT-60SA, in parallel with the vacuum vessel assembly, preparation of the peripheral equipment and related building have been progressed steadily. To send out information to the domestic community a major event in the BA activities.
Ishii, Yasutomo; Matsunaga, Go; Okumura, Yoshikazu
Purazuma, Kaku Yugo Gakkai-Shi, 91(2), p.161 - 162, 2015/02
Success of the first beam of injector for IFMIF prototype accelerator, accomplishment of liquid Lithium Target validation test of the IFMIF/EVEDA and the progress of Satellite Tokamak (JT-60SA) were reported. The IFMIF/EVEDA project are performed in International Fusion Energy Research Center at Rokkasho under the BA agreement, installation and adjustment of injector for IFMIF accelerator were completed and the adjustment beam test has started from Nov. 2014. For the engineering validation test, formability of the Lithium Target which become the neutron source, the Lithium Test Loop of real scale was fabricated in Oarai and test has been conducted for 2 years. At the end of Oct. 2014, made an exceeding achievement and successfully concluded. In the construction of JT-60SA at Naka, the design of each part has been performing with the 3D CAD soft CATIA. The update with previous state discloses on JT60-SA HP. To disseminate information to the domestic community a major event in the BA activities.
Ishii, Yasutomo; Matsunaga, Go; Okumura, Yoshikazu
Purazuma, Kaku Yugo Gakkai-Shi, 90(12), p.827 - 828, 2014/12
Holding of the 15th BA Steering Committee, the 14th IFMIF/EVADA business meeting, the 15th IFERC business meeting and the progress of the Satellite Tokamak (JT-60SA) plan were reported. There were participation of 3 committee members and 8 specialists from EU side and also 30 people which is 4 committees, 7 specialists, each project leaders and project committee chair persons, for the 15th BA Steering Committee and approved for the 2015 Work Plan of IFMIF/EVADA project, the IFERC project and the Satellite Tokamak.6 committees (3 EU side, 3 Japan side), 12 specialists (5 EU, 7 JP) and 8 members of IFMIF/EVADA team, for the 14th IFMIF/EVADA meeting and progress of the each activities were reported.6 committees (3 EU, 3 JP), 16 specialists (9 EU, 7 JP) and 9 members of IFERC team, for the 15th IFERC meeting and reported on progress and discussed about the 2015 Work Plan. In the progress of the JT-60SA plan, assembly work of vacuum chamber is proceeding smoothly in the JT-60 main body room.
Ishii, Yasutomo; Matsunaga, Go
Purazuma, Kaku Yugo Gakkai-Shi, 90(10), p.641 - 643, 2014/10
Loading of the dust from JET (Joint European Torus) to DEMO R&D Building, holding of the joint research joint meeting regarding the BA prototype reactor design and safety, and the progress of the satellite tokamak (JT-60SA) plan are reported. The test sample, carbon and beryllium tiles coated tungsten on the surface, obtained in ITER simulated driving that performed in JET was brought into DEMO R&D building, Rokkasho Institute on August 18, 2014. Preparation of materials analysis has started. The joint research joint meeting of the BA prototype reactor design and safety was held in Rokkaho on July 30-31st. A lively discussion about the current situation and individual design task of Japan-EU prototype reactor design research has taken place. In addition to the JT-60SA tokamak body, the development of heating devices are also progressing well in Naka. To disseminate information to the domestic community a major event in the BA activities.
Ishii, Yasutomo; Matsunaga, Go
Purazuma, Kaku Yugo Gakkai-Shi, 90(8), p.506 - 507, 2014/08
This time, the 5th LIPAc Technical Meeting on June 3-5, Acceptance testing of the RF system for the prototype accelerator, start assembling the JT-60SA vacuum vessel from May, and the 3rd EU-Japan JT-60SA research coordination meeting on May 19-23 are reported. The 5th LIPAc Technical Meeting, Installation in Rokkasho, situation of adjustment work, and preparation status, 38 topics from each agency in each equipment have been reported. In addition, the performance test of RF system for the prototype accelerator that Europe procures was conducted under JAEA, F4E and the project team attendance. Good test results are obtained. The Superconducting tokamak JT-60SA vacuum vessel has started assembling from May. The 3rd JT-60SA EU-Japan Research Coordination Meeting, formulation of a research plan of JT-60SA, and discussion and information exchange of Japanese and EU joint research on JT-60SA were done. To disseminate information to the domestic community a major event in the BA activities.
Ishii, Yasutomo; Matsunaga, Go
Purazuma, Kaku Yugo Gakkai-Shi, 90(6), p.349 - 350, 2014/06
This time, the 14th BA Steering Committee was held at IFERC in Rokkasho, and RF coil was completed in Dec, 2013 at Superconducting Coil Winding Building, Naka Fusion Institute, JAEA were reported. 2 committee members and 3 specialists from EU side, and also 34 people which is 2 committee members, 19 specialists, 3 Project Leaders, and project committee chair persons, for the 14th BA Steering Committee were discussed about the 2013 annual report of the IFMIF/EVEDA project, the IDERC project and Satellite Tokamak were confirmed and those work plans were renewed. The EF5 coil (8.2 m in outside diameter, 23 tons) and the EF6 coil (10.5 m in outside diameter, 33 tons) which bigger than the EF4 coil (4.4 m in outside diameter, 30 tons) that was produced at factory, were produced at Superconducting Coil Winding Building, Naka Fusion Institute, JAEA and were completed in Dec, 2013. To disseminate information in above to the national community a major event in the BA activities.
Hirota, Makoto; Morrison, P. J.*; Ishii, Yasutomo; Yagi, Masatoshi; Aiba, Nobuyuki
Nuclear Fusion, 53(6), p.063024_1 - 063024_11, 2013/06
Times Cited Count：9 Percentile：37.34(Physics, Fluids & Plasmas)A mechanism for fast magnetic reconnection in collisionless plasma is studied for understanding sawtooth collapse in tokamak discharges. Explosive growth of the tearing mode driven by electron inertia is analytically estimated by using an energy principle with a nonlinear displacement map. Decrease of the potential energy in the nonlinear regime (where the island width exceeds the electron skin depth) is found to be steeper than in the linear regime, resulting in accelerated reconnection. Release of free energy by such ideal fluid motion leads to unsteady and strong convective flow, which is not deterred by the small dissipation effects in high-temperature tokamak plasmas. Direct numerical simulation in slab geometry substantiates the theoretical prediction of the nonlinear growth.
Isayama, Akihiko; Matsunaga, Go; Ishii, Yasutomo; Sakamoto, Yoshiteru; Moriyama, Shinichi; Kamada, Yutaka; Ozeki, Takahisa; JT-60 Team
Plasma and Fusion Research (Internet), 5, p.037_1 - 037_6, 2010/10
no abstracts in English
Araki, Masanori; Hayashi, Kimio; Tobita, Kenji; Nishitani, Takeo; Tanigawa, Hiroyasu; Nozawa, Takashi; Yamanishi, Toshihiko; Nakamichi, Masaru; Hoshino, Tsuyoshi; Ozeki, Takahisa; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 86(4), p.231 - 239, 2010/04
The Broader Approach Activities, which support the ITER Project and implement activities to aim early realization of fusion energy, is an EU-Japan collaborative project to carry out various kinds of researches and developments during the period of the ITER construction phase. In this special topic, achievements and prospects of the projects on the International Fusion Energy Research Centre (IFERC) is described.
Ishii, Yasutomo
Plasma and Fusion Research (Internet), 5, p.002_1 - 002_7, 2010/01
no abstracts in English
Ishii, Yasutomo; Smolyakov, A. I.*; Takechi, Manabu
Nuclear Fusion, 49(8), p.085006_1 - 085006_10, 2009/08
Times Cited Count：27 Percentile：69.85(Physics, Fluids & Plasmas)no abstracts in English
Ishii, Yasutomo; Smolyakov, A. I.*
Plasma and Fusion Research (Internet), 3, p.048_1 - 048_7, 2008/08
no abstracts in English
Ishii, Yasutomo; Azumi, Masafumi; Smolyakov, A. I.*
Nuclear Fusion, 47(8), p.1024 - 1032, 2007/08
Times Cited Count：9 Percentile：32.07(Physics, Fluids & Plasmas)no abstracts in English
Ishii, Yasutomo; Azumi, Masafumi; Smolyakov, A. I.*
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03
no abstracts in English
Sekimoto, Hitoshi; Honda, Shuzo*; Kato, Shota*; Ochiai, Yukiko*; Yoneyama, Kaori*; Yoneyama, Koichi*; Takeuchi, Yasutomo*; Kawachi, Naoki; Fujimaki, Shu; Suzui, Nobuo; et al.
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 125, 2007/02
Ishii, Yasutomo; Azumi, Masafumi*; Smolyakov, A. I.*
Journal of Plasma Physics, 72(6), p.1243 - 1248, 2006/12
Times Cited Count：1 Percentile：3.54(Physics, Fluids & Plasmas)no abstracts in English
Takechi, Manabu; Fujita, Takaaki; Ishii, Yasutomo; Ozeki, Takahisa; Suzuki, Takahiro; Isayama, Akihiko; JT-60 Team
Nuclear Fusion, 45(12), p.1694 - 1699, 2005/12
Times Cited Count：7 Percentile：24.62(Physics, Fluids & Plasmas)High performance reversed shear discharges with strong internal transport barrier (ITB) and flat pressure profile in the plasma core region disrupt frequently even with low beta. We analyzed MHD instabilities leading to low beta disruption with measuring fluctuations and current profile with MSE measurement. We mainly observed two type of disruptions. One is the disruption without precursor at 
. The other is the disruption with n=1 precursor of 
100 ms. To explain these characteristics of disruption, we introduce the simple model such as, disruption occurs when the both MHD instabilities at plasma surface and at safety factor being equal to surface mode are unstable. This simple model can explain almost all observed disruption by two process. One is the surface mode triggered disruption, which occurs when qeff change, corresponding q surface at ITB layer changes discretely. The other is the internal mode triggered disruption, which occurs when corresponding q surface become unstable gradually.
Ishii, Yasutomo; Azumi, Masafumi; Kishimoto, Yasuaki
Theory of Fusion Plasmas, ISPP21, p.213 - 226, 2004/00
no abstracts in English
Ishii, Yasutomo; Azumi, Masafumi; Kishimoto, Yasuaki
Physics of Plasmas, 10(9), p.3512 - 3520, 2003/09
Times Cited Count：12 Percentile：37.11(Physics, Fluids & Plasmas)no abstracts in English
Ishii, Yasutomo; Azumi, Masafumi; Kishimoto, Yasuaki; Leboeuf, J. N.*
Nuclear Fusion, 43(7), p.539 - 546, 2003/07
no abstracts in English
