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Oishi, Kazuki*; Igarashi, Daisuke*; Tatara, Ryoichi*; Kawamura, Yukihiko*; Hiroi, Kosuke; Suzuki, Junichi*; Umegaki, Izumi*; Nishimura, Shoichiro*; Koda, Akihiro*; Komaba, Shinichi*; et al.
Journal of Physics; Conference Series, 2462, p.012048_1 - 012048_5, 2023/03
Times Cited Count：0 Percentile：0.21(Physics, Applied)Kobayashi, Takayuki; Isayama, Akihiko; Fasel, D.*; Yokokura, Kenji; Shimono, Mitsugu; Hasegawa, Koichi; Sawahata, Masayuki; Suzuki, Sadaaki; Terakado, Masayuki; Hiranai, Shinichi; et al.
Journal of Plasma and Fusion Research SERIES, Vol.9, p.363 - 368, 2010/08
Improvements are required for expanding the pulse length of the JT-60 ECRF system (5s) for JT-60SA (100s). Newly developed power supplies will be fabricated and installed by EU. The conditioning operation of an improved gyrotron equipping a newly designed mode convertor has been started. The mode convertor will reduce heat flux on the internal components and therefore expected to enable long pulse operation at 1 MW. Pre-programmed and/or feedback control of the heater current and anode voltage, which was successfully demonstrated in JT-60U, will be key techniques because the beam current decreases during a shot. The evacuated transmission lines have a capability of 1 MW per line. Since maintenance of the components in the vacuum vessel is difficult, a linear motion antenna concept was proposed to reduce risks of water leakage and fault of the driving mechanism in the vacuum vessel. The detailed design and the low power test of a mock-up antenna have been started.
Kobayashi, Takayuki; Terakado, Masayuki; Sato, Fumiaki; Yokokura, Kenji; Shimono, Mitsugu; Hasegawa, Koichi; Sawahata, Masayuki; Suzuki, Sadaaki; Hiranai, Shinichi; Igarashi, Koichi; et al.
Plasma and Fusion Research (Internet), 4, p.037_1 - 037_10, 2009/08
Electron cyclotron (EC) heating and current drive (CD) are key tools to control fusion plasma especially for effective electron heating and for suppression of neoclassical tearing mode (NTM). Recently, developments of a high power gyrotron and a power modulation technique have been successfully achieved on JT-60U ECRF system in order to enhance the system performance. Stable gyrotron oscillation with oscillation power of 1.5 MW for 1 s was demonstrated in 2007, for the first time. Then temperature rise of cavity and collector has been investigated. It has been shown that the longer pulse operation with 1.5 MW by an improved 110 GHz gyrotron is possible. In addition, modulated ECCD in synchronized with NTM rotation has been performed with the oscillation power of 0.8 MW and the frequency around 5 kHz. The synchronizing system has worked very well and it has played an essential role in NTM suppression experiments on JT-60U.
Moriyama, Shinichi; Kobayashi, Takayuki; Isayama, Akihiko; Terakado, Masayuki; Sawahata, Masayuki; Suzuki, Sadaaki; Yokokura, Kenji; Shimono, Mitsugu; Hasegawa, Koichi; Hiranai, Shinichi; et al.
Nuclear Fusion, 49(8), p.085001_1 - 085001_7, 2009/07
Times Cited Count：21 Percentile：61.58(Physics, Fluids & Plasmas)In the gyrotron development in JT-60U ECRF system, output power of 1.5 MW for 1 s has been achieved at 110 GHz. It is the world highest power oscillation 
1 s. In addition to the carefully designed cavity and collector in view of thermal stress, an RF shield for the adjustment bellows, and a low-dielectric-loss DC break enabled this achievement. Power modulation technique by anode voltage control was improved to obtain high modulation frequency and 5 kHz has been achieved for NTM stabilizing experiments. Long pulse demonstration of 0.4 MW, 30 s injection to the plasma has been achieved with real time control of anode/cathode-heater. It has been confirmed that the temperature of cooled components were saturated and no evidence of damage were found. An innovative antenna having wide range of beam steering capability with linearly-moving-mirror concept has been designed for long pulse. Beam profile and mechanical strength analyses shows the feasibility of the antenna.
Yokokura, Kenji; Shimono, Mitsugu; Hasegawa, Koichi; Sawahata, Masayuki; Suzuki, Sadaaki; Terakado, Masayuki; Hiranai, Shinichi; Igarashi, Koichi; Sato, Fumiaki; Wada, Kenji; et al.
JAEA-Technology 2008-065, 98 Pages, 2008/10
JAEA-Technology-2008-065.pdf:38.83MB
Construction of the JT-60SA (super advanced) is planned as an upgrade of JT-60U as the satellite tokamak in ITER broader approach and as the national centralized tokamak facility program in Japan. The present JT-60U will be disassembled and the JT-60SA will be constructed at the same location in the JT-60 tours hall. The disassembly work will be planned in the period from 2009 to 2011. In this report, disassembly of the radio frequency heating system of JT-60U in the amplifier rooms and heating power supply building is studied on (1) object for disassembly, (2) work plan, (3) estimation of materials amount, (4) procedure.
Moriyama, Shinichi; Kobayashi, Takayuki; Isayama, Akihiko; Terakado, Masayuki; Sawahata, Masayuki; Suzuki, Sadaaki; Yokokura, Kenji; Shimono, Mitsugu; Hasegawa, Koichi; Hiranai, Shinichi; et al.
Proceedings of 22nd IAEA Fusion Energy Conference (FEC 2008) (CD-ROM), 8 Pages, 2008/10
In the gyrotron development in JT-60U ECRF system, output power of 1.5 MW for 1 s has been achieved at 110 GHz. It is the world highest power oscillation 1 s. In addition to the carefully designed cavity and collector in view of thermal stress, an RF shield for the adjustment bellows, and a low-dielectric-loss DC break enabled this achievement. Power modulation technique by anode voltage control was improved to obtain high modulation frequency and 5 kHz has been achieved for NTM stabilizing experiments. Long pulse demonstration of 0.4 MW, 30 s injection to the plasma has been achieved with real time control of anode/cathode-heater. It has been confirmed that the temperature of cooled components were saturated and no evidence of damage were found. An innovative antenna having wide range of beam steering capability with linearly-moving-mirror concept has been designed for long pulse. Beam profile and mechanical strength analyses shows the feasibility of the antenna.
Igarashi, Shinichi*; Itakura, Akiko*; Kitajima, Masahiro*; Nakano, Shinsuke*; Muto, Shunsuke*; Tanabe, Tetsuo*; Yamamoto, Hiroyuki; Hojo, Kiichi
Japanese Journal of Applied Physics, Part 1, 45(5A), p.4179 - 4182, 2006/05
Times Cited Count：3 Percentile：12.91(Physics, Applied)By utilizing surface stress to modify surface reaction potential and increase surface reactivity, a technique for the twodimensional patterning of surface chemical reactions may be realized by surface stress modulation. A blister is a local protrusion on a solid surface induced by gas ion irradiation, and is considered to create local stress on surface layers. Si(100) substrate was irradiated with H
(incident energy: 10 keV, fluence: 1
10
ions) at an angle of 30 to the surface normal. Blisters of 1-5 mm in diameter at the base were formed. After the ion irradiation, the substrate was oxidized. Scanning Auger electron microscopy revealed that, compared with the flat surface, the perimeters of the blisters had a higher oxygen intensity whereas the blister tops had a lower oxygen intensity. The stress distribution of the blister was calculated using the finite element method. It was found that the surface layers were stretched laterally at the blisters tops and compressed at theperimeters, relative to the flat surface. There was a clear correspondence between the O distribution and the stress distribution on the surface. Our results indicate that the patterned oxidation of the Si surface can be governed by the application of surface stress.
Igarashi, Shinichi*; Itakura, Akiko*; Kitajima, Masahiro*; Nakano, Shinsuke*; Muto, Shunsuke*; Tanabe, Tetsuo*; Yamamoto, Hiroyuki; Hojo, Kiichi
Hyomen Kagaku, 25(9), p.562 - 567, 2004/09
Surface stress can be utilized positively in modifying the surface reaction potential and increasing the surface reactivity. Blister is a local protrusion of solid surface induced by gas ion irradiation, and is considered to create local stress on surface layers. Si(100) substrate was irradiated with 10 keV H (fluence; 110 ions/m
) at an angle of 30
to the surface normal. The blisters of several 
m in diameter at the bottom were formed. After the ion irradiation, the substrate was oxidized. By means of scanning Auger microscopy, we observed that the rims of the blisters have higher oxygen intensities than the flat surfaces and the tops have lower than the flats. The calculated stress distribution of the blister shows that the surface layers should be stretched laterally at the top of blisters and are compressed at the rim, relative to the flat surfaces. The O distribution clearly consists with the stress distribution of the surface. Our results demonstrate a patterned oxidation of Si surface applying its reactivity depending on the surface stress.
Igarashi, Shinichi*; Haraguchi, Masaharu*; Aihara, Jun; Saito, Takeru*; Yamaguchi, Kenji; Yamamoto, Hiroyuki; Hojo, Kiichi
Journal of Electron Microscopy, 53(3), p.223 - 228, 2004/08
Times Cited Count：4 Percentile：24.19(Microscopy)no abstracts in English
Igarashi, Shinichi*; Katsumata, Toshinobu*; Haraguchi, Masaharu*; Saito, Takeru*; Yamaguchi, Kenji; Yamamoto, Hiroyuki; Hojo, Kiichi
Vacuum, 74(3-4), p.619 - 624, 2004/06
Times Cited Count：6 Percentile：27.8(Materials Science, Multidisciplinary)no abstracts in English
-FeSi
filmsIgarashi, Shinichi; Katsumata, Toshinobu; Haraguchi, Masaharu; Saito, Takeru; Yamaguchi, Kenji; Yamamoto, Hiroyuki; Hojo, Kiichi
Transactions of the Materials Research Society of Japan, 28(4), p.1153 - 1156, 2003/12
We have evaluated the crystal structure of the -FeSi films formed with various sputter etching of Si substrate. Ne sputter etching of Si (100) substrate was performed with ion energies of 1, 3, and 10 keV. After each etching, the substrate was annealed at a temperature of 1073 K for 30 min. The -FeSi films of 100 nm in thickness were formed at 973 K with the amount of deposited Fe, 30 nm. X-ray diffraction revealed that these films have polycrystalline -FeSi structure but strong preferential orientation aligned as -FeSi (100) // Si (100). Furthermore, the oriented structure of the film was improved by lowering the incident energy of Ne.
Shimono, Mitsugu; Seki, Masami; Terakado, Masayuki; Igarashi, Koichi*; Ishii, Kazuhiro*; Takahashi, Masami*; Shinozaki, Shinichi; Hiranai, Shinichi; Sato, Fumiaki*; Anno, Katsuto
JAERI-Tech 2003-075, 29 Pages, 2003/09
JAERI-Tech-2003-075.pdf:4.62MB
no abstracts in English
Igarashi, Shinichi; Muto, Shunsuke*; Tanabe, Tetsuo*; Aihara, Jun; Hojo, Kiichi
Surface & Coatings Technology, 158-159, p.421 - 425, 2002/09
no abstracts in English
equilibrium potential measurements in LiCl-KCl eutectic meltKobayashi, Fumiaki; *; *; *
JAERI-Tech 99-006, 19 Pages, 1999/02
no abstracts in English
Moriyama, Shinichi; Yokokura, Kenji; Hasegawa, Koichi; Suzuki, Sadaaki; Hiranai, Shinichi; Ishii, Kazuhiro; Sato, Fumiaki; Tani, Takashi; Igarashi, Koichi; Shimono, Mitsugu; et al.
no journal, ,
no abstracts in English
Fujii, Tsuneyuki; Seki, Masami; Moriyama, Shinichi; Terakado, Masayuki; Suzuki, Sadaaki; Shinozaki, Shinichi; Sawahata, Masayuki; Hiranai, Shinichi; Igarashi, Koichi; Shimono, Mitsugu
no journal, ,
no abstracts in English
Fujii, Tsuneyuki; Seki, Masami; Moriyama, Shinichi; Terakado, Masayuki; Sawahata, Masayuki; Shinozaki, Shinichi; Suzuki, Sadaaki; Hiranai, Shinichi; Igarashi, Koichi; Shimono, Mitsugu
no journal, ,
no abstracts in English
Moriyama, Shinichi; Fujii, Tsuneyuki; Seki, Masami; Sawahata, Masayuki; Suzuki, Sadaaki; Shinozaki, Shinichi; Terakado, Masayuki; Hiranai, Shinichi; Hasegawa, Koichi; Shimono, Mitsugu; et al.
no journal, ,
no abstracts in English
Moriyama, Shinichi; Kobayashi, Takayuki; Yokokura, Kenji; Shimono, Mitsugu; Hasegawa, Koichi; Sawahata, Masayuki; Suzuki, Sadaaki; Terakado, Masayuki; Hiranai, Shinichi; Igarashi, Koichi; et al.
no journal, ,
The electron cycrotron range of frequency (ECRF) system (3 MW
5 s at 110 GHz with 4 gyrotrons) will be upgraded to the system having 9 gyrotrons (7 MW 100 s at 110 GHz and 140 GHz) for JT-60SA (super advanced). For the reference antenna design having rotary mirrors, an effective and reliable method of mirror cooling without water is under consideration. As an alternative antenna design, a new concept with a mirror driven in the linear motion which eliminates the flexible tube for coolant supply is under development. The design study featuring beam profile calculation showed feasibility of the antenna in the 0.48 m 0.48 m port. On the gyrotron development, 1.5 MW, 1s has been achieved using Si
N
insulator instead of AlO. Improvement of the mode converter is in progress and the test aiming at 1 MW, 100 s oscillation will be started in March.
Moriyama, Shinichi; Kobayashi, Takayuki; Yokokura, Kenji; Shimono, Mitsugu; Hasegawa, Koichi; Sawahata, Masayuki; Suzuki, Sadaaki; Terakado, Masayuki; Hiranai, Shinichi; Igarashi, Koichi; et al.
no journal, ,
no abstracts in English
