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Maeda, Soshu*; Nago, Makito*; Aoyagi, Kazuhei; Sugawara, Kentaro*; Kodama, Junichi*
Shigen, Sozai Koenshu (Internet), 12(2), 5 Pages, 2025/09
no abstracts in English
Kawashima, Hiroyuki; Kurosawa, Takuma*; Teshigawara, Makoto; Naoe, Takashi; Tanaka, Nobuatsu*; Futakawa, Masatoshi; Kogawa, Hiroyuki
Advanced Experimental Mechanics, 7, p.43 - 48, 2022/08
Laser cutting is expected for reducing the volume of radioactive components by taking account of radioactive levels. The scattering of radioactive dust such as fume and spatter, which is generated throughout the laser cutting process, gets to be a major issue for practical usage in cutting highly radioactive substances. One of driving forces of the spatter is likely to be attributed to the cavitation bubble collapsing caused by rapid thermal loading due to laser irradiation. In order to elucidate the mechanism of spattering, the technique of spark discharge in water was availed to generate the cavitation bubble. The growth and collapse behaviors influenced by the interaction between a free surface and bubbles resulting the spattering phenomena are observed by using an ultra-high-speed video camera, and the numerical simulation was carried out as well.
Hasegawa, Kunio; Li, Y.; Kim, Y.-J.*; Lacroix, V.*; Strnadel, B.*
Journal of Pressure Vessel Technology, 141(3), p.031201_1 - 031201_5, 2019/06
Times Cited Count：1 Percentile：4.14(Engineering, Mechanical)When discrete multiple flaws are in the same plane, and they are close to each other, it can be determined whether they are combined or standalone in accordance with combination rules provided by Fitness-For-Service (FFS) codes. However, specific criteria of the rules are different amongst these FFS codes. On the other hand, plastic collapse bending stresses for stainless steel pipes with two circumferential similar flaws were obtained by experiments and the prediction procedure for collapse stresses for pipes with two similar flaws were developed analytically. Using the experimental data and the analytical procedure, plastic collapse stresses for pipes with two similar flaws are compared with the stresses in compliance with the flaw combination criteria. It is shown that the calculated plastic collapse stresses based on the flaw combination criteria are significantly different from the experimental and analytical stresses.
Oyama, Naoyuki; Sakamoto, Yoshiteru; Isayama, Akihiko; Takechi, Manabu; Gohil, P.*; Lao, L. L.*; Snyder, P. B.*; Fujita, Takaaki; Ide, Shunsuke; Kamada, Yutaka; et al.
Nuclear Fusion, 45(8), p.871 - 881, 2005/08
Times Cited Count：127 Percentile：94.97(Physics, Fluids & Plasmas)The grassy ELM is characterized by the high frequency periodic collapse up to 
kHz, which is 15 times faster than that for type I ELM. A divertor peak heat flux due to grassy ELMs is less than 10% of that for type I ELMs. This smaller heat flux is caused by narrower radial extent of the collapse of temperature pedestal. The different radial extent between type I ELMs and grassy ELMs qualitatively agrees with the different radial distribution of the eigen function of the ideal MHD stability analysis. The ratio of ELM energy loss for grassy ELMs to the pedestal stored energy was 0.4-1%. In high triangularity regime, ELM amplitude, frequency and type can be changed from type I ELM to high frequency grassy ELM as counter plasma rotation was increased. In low triangularity regime, on the other hand, the complete ELM suppression (QH-mode) has been achieved, when the plasma position is optimized with CTR-NBIs. The existence of the edge fluctuations localized in pedestal region may reduce the pedestal pressure, and therefore the QH-mode can be sustained for long time up to 3.4s.
Fujii, Yasuhiko
Koatsuryoku No Kagaku To Gijutsu, 14(2), p.113 - 118, 2004/05
no abstracts in English
Oyama, Naoyuki; Miura, Yukitoshi; Chankin, A. V.; Takenaga, Hidenobu; Asakura, Nobuyuki; Kamada, Yutaka; Oikawa, Toshihiro; Shinohara, Koji; Takeji, Satoru
Nuclear Fusion, 43(10), p.1250 - 1257, 2003/10
Times Cited Count：16 Percentile：44.91(Physics, Fluids & Plasmas)no abstracts in English
Matsumoto, Taro; Tokuda, Shinji; Kishimoto, Yasuaki; Naito, Hiroshi*
Physics of Plasmas, 10(1), p.195 - 203, 2003/01
Times Cited Count：5 Percentile：16.36(Physics, Fluids & Plasmas)Effects of density gradient on the collisionless m=1 internal kink mode in a cylindrical tokamak plasma are studied by the gyro-kinetic particle simulations. When the density gradient is not large enough to change the full reconnection process, the phenomena after the full reconnection, such as the secondary reconnection and the evolution of the safety factor profile, are changed considerably due to the self-generated radial electric field, i.e. the m=0 mode. The growing mechanism is explained by the difference of 
drift motion between ions and electrons, which is caused by the fast parallel motion of electron. Once the radial electric field is triggered by the symmetrical flow induced by the m=1 mode, the m=0 mode grows up to the same level as the m=1 mode, and drives an plasma rotation in the ion diamagnetic direction, which breaks the symmetrical plasma flow induced by the m=1 mode. The density and current distributions, and minimum safety factor after the full reconnection, are found to be affected by the asymmetrical flow driven by the m=1 and m=0 modes.
Matsumoto, Taro; Tokuda, Shinji; Kishimoto, Yasuaki; Takizuka, Tomonori; Naito, Hiroshi*
Purazuma, Kaku Yugo Gakkai-Shi, 75(10), P. 1194, 1999/10
no abstracts in English
Matsumoto, Taro; Tokuda, Shinji; Kishimoto, Yasuaki; Takizuka, Tomonori; Naito, Hiroshi*
Journal of Plasma and Fusion Research SERIES, Vol.2, p.97 - 100, 1999/00
no abstracts in English
p mode plasmas in the Japan Atomic Energy Research Institute Tokamak-60 upgradeTakeji, Satoru; Kamada, Yutaka; Ozeki, Takahisa; Ishida, Shinichi; Takizuka, Tomonori; Neyatani, Yuzuru; Tokuda, Shinji
Physics of Plasmas, 4(12), p.4283 - 4291, 1997/12
Times Cited Count：16 Percentile：48.86(Physics, Fluids & Plasmas)no abstracts in English
Nakamura, Yukiharu; Nishio, Satoshi; Yoshino, Ryuji; C.E.Kessel*; S.C.Jardin*
Purazuma, Kaku Yugo Gakkai-Shi, 72(12), p.1387 - 1396, 1996/12
no abstracts in English
-collapse-induced vertical displacement event in high tokamak disruptionNakamura, Yukiharu; Yoshino, Ryuji; N.Pomphrey*; S.C.Jardin*
Plasma Physics and Controlled Fusion, 38(10), p.1791 - 1804, 1996/10
Times Cited Count：19 Percentile：54.09(Physics, Fluids & Plasmas)no abstracts in English
Nakamura, Yukiharu; Yoshino, Ryuji; N.Pomphrey*; S.C.Jardin*
Journal of Nuclear Science and Technology, 33(8), p.609 - 619, 1996/08
Times Cited Count：11 Percentile：66.96(Nuclear Science & Technology)no abstracts in English
; Abe, Yutaka*; ; ; Yamano, N.; Sugimoto, Jun
JAERI-Research 96-032, 152 Pages, 1996/06
JAERI-Research-96-032.pdf:4.05MB
no abstracts in English
collapse in high tokamak disruptionsNakamura, Yukiharu; Yoshino, Ryuji; N.Pomphrey*; S.C.Jardin*
JAERI-Research 96-023, 15 Pages, 1996/05
JAERI-Research-96-023.pdf:0.79MB
no abstracts in English
and high-
discharges in JT-60UNeyatani, Yuzuru; Kamada, Yutaka; Ozeki, Takahisa; Ishida, Shinichi
Plasma Physics and Controlled Fusion, 37(7), p.741 - 753, 1995/07
Times Cited Count：9 Percentile：40.28(Physics, Fluids & Plasmas)no abstracts in English
p plasmas and p collapse in JT-60UOzeki, Takahisa; Azumi, Masafumi; Kamada, Yutaka; Ishida, Shinichi; Neyatani, Yuzuru; Tokuda, Shinji
Nuclear Fusion, 35(7), p.861 - 871, 1995/00
Times Cited Count：30 Percentile：69.80(Physics, Fluids & Plasmas)no abstracts in English
Yoshino, Ryuji; Neyatani, Yuzuru; Isei, Nobuaki; Matsukawa, Makoto; Hosogane, Nobuyuki
Purazuma, Kaku Yugo Gakkai-Shi, 70(10), p.1081 - 1101, 1994/10
no abstracts in English
Nishitani, Takeo; Ishida, Shinichi; Kikuchi, Mitsuru; Azumi, Masafumi; Yamagiwa, Mitsuru; Fujita, Takaaki; Kamada, Yutaka; Kawano, Yasunori; Koide, Yoshihiko; Hatae, Takaki; et al.
Nuclear Fusion, 34(8), p.1069 - 1079, 1994/00
Times Cited Count：29 Percentile：67.87(Physics, Fluids & Plasmas)no abstracts in English
Ishida, Shinichi; Matsuoka, Mamoru; Kikuchi, Mitsuru; Tsuji, Shunji; Nishitani, Takeo; Koide, Yoshihiko; Ozeki, Takahisa; Fujita, Takaaki; Nakamura, Hiroo; Hosogane, Nobuyuki; et al.
Plasma Physics and Controlled Nuclear Fusion Research 1992, Vol.1, p.219 - 233, 1993/00
no abstracts in English
