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Itakura, Ryuji; Kumada, Takayuki; Nakano, Motoyoshi*; Akagi, Hiroshi
Optics Express (Internet), 23(9), p.10914 - 10924, 2015/05
Times Cited Count：17 Percentile：65.18(Optics)We propose and experimentally demonstrate a method for characterizing vacuum ultraviolet (VUV) pulses based on time-resolved reflection spectroscopy of fused silica pumped by an intense laser pulse. Plasma mirror reflection is used as an ultrafast optical switch, which enables us to measure frequency-resolved optical gating (FROG) traces. The VUV temporal waveform can be retrieved from the measured FROG trace using principal component generalized projections algorithm with modification. The temporal profile of the plasma mirror reflectivity is also extracted simultaneously.
Ida, Masato
Nihon Ryutai Rikigakkai Nenkai 2005 Koen Rombunshu (CD-ROM), 6 Pages, 2005/09
The resonance frequencies and oscillation phases of three acoustically coupled bubbles in a fluid are examined to show that avoided crossings can appear in a few-bubble system. Using a simple coupled oscillator model, we show that if at least three bubbles exist, it is possible for their resonance frequencies as functions of the separation distances between the bubbles to experience an avoided crossing. Furthermore, by focusing our attention on the oscillation phases and the transition frequencies [Ida, Phys. Lett. A 297, 210 (2002); J. Phys. Soc. Jpn. 71, 1214 (2002)] of the coupled bubbles, we show that a distinct state exchange takes place between the bubbles at a point in the avoided crossing region, where a resonance frequency of the triple-bubble system crosses with a transition frequency not corresponding to the resonance frequencies.
Ida, Masato
Physical Review E, 72(3), p.036306_1 - 036306_7, 2005/09
Times Cited Count：14 Percentile：53.94(Physics, Fluids & Plasmas)The resonance frequencies and oscillation phases of three acoustically coupled bubbles are examined to show that avoided crossings can appear in a multibubble system. Via a simple coupled oscillator model, we show that if at least three bubbles exist, it is possible for their resonance frequencies to experience an avoided crossing. Furthermore, by focusing our attention on the oscillation phases and based on analysis of the transition frequencies [Ida, Phys. Lett. A 297, 210 (2002); Ida, J. Phys. Soc. Jpn. 71, 1214 (2002)] of the coupled bubbles, we show that a distinct state exchange takes place between the bubbles at a point in the avoided crossing region, where a resonance frequency of the triple-bubble system crosses with a transition frequency.
Ida, Masato
Physics of Fluids, 17(9), p.097107_1 - 097107_13, 2005/09
Times Cited Count：16 Percentile：52.73(Mechanics)The transition frequencies of multibubble systems in a sound field are reexamined theoretically to confirm their existence and further clarify their physical properties. Via a forced coupled oscillator model, the following results are obtained: (1) further details of the characteristics of the transition frequencies, (2) the theoretical determination of the threshold distances for the appearance of the sub-transition frequencies, (3) a simple understanding of the sign reversal of the interaction force, and (4) the clarification of several similarities and differences among the natural, resonance, and transition frequencies in double-bubble cases. The present effort enforces our claim that transition frequencies causing no resonance response exist in multibubble systems and thoroughly clarifies the physical effects of the transition frequencies and their roles in the sign reversal of the interaction force.
n eigenmodes driven by negative-ion-based neutral beams in JT-60UShinohara, Koji; Ishikawa, Masao; Takechi, Manabu; Kusama, Yoshinori; Todo, Yasushi*; Gorelenkov, N. N.*; Cheng, C. Z.*; Fukuyama, Atsushi*; Kramer, G.*; Nazikian, R. M.*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 81(7), p.547 - 552, 2005/07
In the bursting instabilities in the frequency range of Alfven Eigenmode, we observed two types of modes phenomenologically. In one type, the time scale of the mode was 
1ms and the mode amplitude was so large that we were able to detect apparent enhanced transport of the energetic ions. The enhanced transport showed the clear energy dependence by using new diagnostics, natural diamond detector. In another type, the mode amplitude is not so large, compared with the first type. The frequency up-down chirping is clearly observed with the time-scale of a few ms. This frequency chirping was reproduced by the newly developed simulation code, MEGA To demonstrate this model of Reversed-Shear-induced Alfven Eigenmode, RSAE, we have performed experiments in the condition where we can have q profile with a good signal-to-noise ratio. We observed the slow up-frequency sweeping of RSAE due to the down evolution of qmin, We have analyzed this experiment by using NOVA-K code. We observed that the most unstable mode localized around qmin.
Honda, Atsushi; Kawai, Mikito; Okano, Fuminori; Oshima, Katsumi*; Numazawa, Susumu*; Oga, Tokumichi; Ikeda, Yoshitaka
Heisei-16-Nendo Osaka Daigaku Sogo Gijutsu Kenkyukai Hokokushu (CD-ROM), 4 Pages, 2005/03
no abstracts in English
Omori, Shunzo
Sangyo To Denki, (629), p.1 - 2, 2005/02
no abstracts in English
Kotaki, Hideyuki; Masuda, Shinichi; Kando, Masaki; Kondo, Shuji; Kanazawa, Shuhei; Homma, Takayuki; Nakajima, Kazuhisa
Quantum Aspects of Beam Physics 2003, p.119 - 124, 2004/10
Times Cited Count：0 Percentile：0.4(Astronomy & Astrophysics)no abstracts in English
Ida, Masato
Proceedings of 6th World Congress on Computational Mechanics in conjunction with 2nd Asian-Pacific Congress on Computational Mechanics (CD-ROM), p.1 - 11, 2004/09
The existence of the "transition frequencies" of two acoustically coupled gas bubbles has been verified by direct numerical simulation. The theory described by Ida [Phys. Lett. A 297 (2002) 210] predicted that a bubble in the double-bubble system has three transition frequencies, some of which makes the phase difference between the bubble's volume oscillation and an external sound 
without accompanying resonance response of the bubble. In a more recent paper [Ida, Phys. Rev. E 67 (2003) 056617], it was suggested theoretically that one of the transition frequencies may cause the sign reversal of the secondary Bjerknes force acting between pulsating bubbles. In the present study, we employ a direct numerical simulation technique that uses the compressible Navier-Stokes equations with a surface-tension term as the governing equations to investigate the transition frequencies of two coupled bubbles. The numerical results clearly exhibit the existence of the theoretically predicted characteristic frequency.
Sakamoto, Yoshiteru; Shirai, Hiroshi; Fujita, Takaaki; Ide, Shunsuke; Takizuka, Tomonori; Oyama, Naoyuki; Kamada, Yutaka
Plasma Physics and Controlled Fusion, 46(5A), p.A299 - A304, 2004/05
Times Cited Count：68 Percentile：88.47(Physics, Fluids & Plasmas)no abstracts in English
Maebara, Sunao; Morishita, Takatoshi; Moriyama, Shinichi; Sugimoto, Masayoshi; Imai, Tsuyoshi; Takeuchi, Hiroshi
Proceedings of 28th Linear Accelerator Meeting in Japan, P. 378, 2003/08
no abstracts in English
Hori, Toshihiko*; Ito, Takashi; Yamazaki, Masayoshi*; Chishiro, Etsuji; Hasegawa, Kazuo
Proceedings of 28th Linear Accelerator Meeting in Japan, p.285 - 287, 2003/07
no abstracts in English
Ikeda, Yoshitaka; Kasugai, Atsushi; Moriyama, Shinichi; Kajiwara, Ken*; Seki, Masami; Tsuneoka, Masaki*; Takahashi, Koji; Anno, Katsuto; Hamamatsu, Kiyotaka; Hiranai, Shinichi; et al.
Fusion Science and Technology (JT-60 Special Issue), 42(2-3), p.435 - 451, 2002/09
Times Cited Count：26 Percentile：82.29(Nuclear Science & Technology)no abstracts in English
n eigenmode experiments using N-NB in JT-60U tokamakShinohara, Koji; Takechi, Manabu; Ishikawa, Masao*; Kusama, Yoshinori; Morioka, Atsuhiko; Oyama, Naoyuki; Tobita, Kenji; Ozeki, Takahisa; JT-60 Team; Gorelenkov, N. N.*; et al.
Nuclear Fusion, 42(8), p.942 - 948, 2002/08
Times Cited Count：43 Percentile：77.26(Physics, Fluids & Plasmas)no abstracts in English
Kotaki, Hideyuki; Kando, Masaki; Oketa, Takatsugu; Masuda, Shinichi; Koga, J. K.; Kondo, Shuji; Kanazawa, Shuhei; Yokoyama, Takashi*; Matoba, Toru; Nakajima, Kazuhisa
Physics of Plasmas, 9(4), p.1392 - 1400, 2002/04
Times Cited Count：47 Percentile：79.44(Physics, Fluids & Plasmas)no abstracts in English
Takei, Nahoko; Ozeki, Takahisa; Smolyakov, A. I.*; Isayama, Akihiko; Hayashi, Nobuhiko; Iio, Shunji*; Shimada, Ryuichi*
Journal of Plasma and Fusion Research SERIES, Vol.5, p.386 - 389, 2002/00
no abstracts in English
Yamamoto, Toshihiro
Noizu Za Ribaibaru, p.165 - 171, 2001/11
no abstracts in English
n eigenmodes driven by Alfnic beam ions in JT-60UShinohara, Koji; Kusama, Yoshinori; Takechi, Manabu; Morioka, Atsuhiko; Ishikawa, Masao*; Oyama, Naoyuki; Tobita, Kenji; Ozeki, Takahisa; Takeji, Satoru; Moriyama, Shinichi; et al.
Nuclear Fusion, 41(5), p.603 - 612, 2001/05
Times Cited Count：83 Percentile：90.18(Physics, Fluids & Plasmas)no abstracts in English
Chishiro, Etsuji; Tsukishima, Chihiro*; Ouchi, Nobuo; Mukugi, Ken*; Hasegawa, Kazuo; Mizumoto, Motoharu
KEK Proceedings 2000-23, p.34 - 38, 2001/02
no abstracts in English
Kotaki, Hideyuki; Kando, Masaki; Kondo, Shuji; Masuda, Shinichi; Kanazawa, Shuhei; Yokoyama, Takashi*; Matoba, Toru; Nakajima, Kazuhisa
Proceedings of 13th Symposium on Accelerator Science and Technology, 3 Pages, 2001/00
no abstracts in English
