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Skobelev, I. Yu.*; Ryazantsev, S. N.*; Kulikov, R. K.*; Sedov, M. V.*; Filippov, E. D.*; Pikuz, S. A.*; Asai, Takafumi*; Kanasaki, Masato*; Yamauchi, Tomoya*; Jinno, Satoshi; et al.
Photonics (Internet), 10(11), p.1250_1 - 1250_11, 2023/11
Times Cited Count：0 Percentile：0(Optics)It is challenging to clearly distinguish the impacts of the optical field and collisional ionization in the evolution of the charge state of a plasma produced when matter interacts with high-intensity laser pulses. In this work, time-dependent calculations of plasma kinetics are used to show that it is possible only when low-density gaseous targets with sufficiently small clusters are used. In the case of Ar plasma, the upper limit of the cluster radius was estimated to be 
m.
Iwase, Akihiro*; Chimi, Yasuhiro; Ishikawa, Norito; Nakatani, Rikizo*; Kato, Yuzaburo*; Fukuzumi, Masafumi*; Tsuchida, Hidetsugu*; Baba, Yuji
Nuclear Instruments and Methods in Physics Research B, 245(1), p.141 - 144, 2006/04
Times Cited Count：0 Percentile：0.01(Instruments & Instrumentation)Diffusion of Si atoms in Pd under energetic ion irradiation is studied in Pd-Si thin layer system using synchrotron radiation photoemission spectroscopy. Specimens are prepared by depositing Pd on Si single crystals. The Pd layer thicknesses are 10-300 nm. Before irradiation, we observe photoemission spectra only for Pd, but do not find any trace of Si. After irradiation with 3-MeV Si ions, 1-MeV O ions or 200-MeV Xe ions, we observe an additional photoemission component at the binding energy about 3 eV higher than that of Si 1s bulk component. The experimental result implies that the energetic ion-irradiation induces the diffusion of Si atoms from the Si-Pd interface to the Pd layer surface. The shift of the binding energy from the value for the Si bulk can be interpreted as arising from electron charge transfer from Si to Pd. The dependences of photoemission spectra and ion-irradiation induced diffusion on ion-species and ion-fluence are discussed.
Ono, Fumihisa*; Kanamitsu, Hiroaki*; Matsushima, Yasushi*; Chimi, Yasuhiro; Ishikawa, Norito; Kambara, Tadashi*; Iwase, Akihiro*
Nuclear Instruments and Methods in Physics Research B, 245(1), p.166 - 170, 2006/04
Times Cited Count：4 Percentile：34.39(Instruments & Instrumentation)Specimens of both ordered and disordered Fe-28.3at.%Pt alloys were irradiated with 200-MeV Xe ions to the fluence of 10
ions/cm. Measurements of AC-susceptibility-temperature curves were made for each specimen before and after the irradiation by using a specially designed apparatus for rapid measurements. In contrast to the expectation from the previous results for Fe-Ni alloys, in disordered Fe-Pt invar alloy the Curie temperature, T
decreased about 15 K by the irradiation. This fact cannot be explained by considering the lattice expansion effect alone. In Fe-Pt invar alloys the effect of lattice expansion may be cancelled out by some other effects which may be originated from the large difference in atomic mass between the two elements. For ordered Fe-Pt alloy, T decreased as large as 60 K with the same fluence. The value of T for both ordered and disordered Fe-Pt invar alloys coincide with each other after the irradiation. This fact can be explained by considering that the ordered state becomes disordered by the irradiation.
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.
Todo, Yasushi*; Shinohara, Koji; Takechi, Manabu; Ishikawa, Masao
Physics of Plasmas, 12(1), p.012503_1 - 012503_7, 2005/01
Times Cited Count：51 Percentile：82.4(Physics, Fluids & Plasmas)Energetic-ion driven instability in a JT-60U plasma was investigated using a simulation code for magnetohydrodynamics and energetic particles. The spatial profile of the unstable mode peaks near the plasma center where the safety factor profile is flat and the spatial profile consists of a single primary harmonic m/n = 2/1. The real frequency of the unstable mode is close to the experimental starting frequency of the fast frequency sweeping mode. Simulation results demonstrate that energetic ion orbit width and energetic ion pressure significantly broaden radial profile of the unstable mode. For the smallest value among the investigated energetic ion orbit width, the unstable mode is localized within 20% of the minor radius. This gives an upper limit of the spatial profile width of the unstable mode which the magnetohydrodynamic effects alone can induce. For the experimental condition of the JT-60U plasma, energetic ions broaden the radial width of the unstable mode spatial profile by a factor of 3. The unstable mode is primarily induced by the energetic particles.
Kusama, Yoshinori; Ishikawa, Masao; Takechi, Manabu; Nishitani, Takeo; Morioka, Atsuhiko; Sasao, Mamiko*; Isobe, Mitsutaka*; Krasilnikov, A.*; Kaschuck, Y.*
Proceedings of Plasma Science Symposium 2005/22nd Symposium on Plasma Processing (PSS-2005/SPP-22), p.395 - 396, 2005/00
The energetic neutral particles have been successfully measured with a natural diamond detector in the neutron and 
ray radiation circumstance of the JT-60U deuterium discharges. The diamond detector was covered with polyethylene and lead in order to reduce the neutron and ray background. The shield has shown expected shielding capability. A rapid increase in neutral particles has been observed at the onset of the Toroidal Alfven Eigenmode (TAE) excited by the negative-ion-based neutral beam injection. The energy range of increased neutral particles has agreed well with that predicted from the resonant interaction between the energetic ions and the TAE.
Isobe, Mitsutaka*; Shinohara, Koji
Purazuma, Kaku Yugo Gakkai-Shi, 80(12), p.1036 - 1043, 2004/12
Escaping energetic ion diagnostics in magnetically confined plasma experiments are described in this lecture note. Experimental results from escaping energetic ion diagnostics in TFTR, JFT-2M, CHS and W7-AS are shown. In addition to mechanism of energetic ion loss from a viewpoint of particle orbit, effect of MHD activity on energetic particle transport is reviewed.
n eigenmodesTodo, Yasushi*; Nakajima, Noriyoshi*; Shinohara, Koji; Takechi, Manabu; Ishikawa, Masao; Yamamoto, Satoshi*
Proceedings of 20th IAEA Fusion Energy Conference (FEC 2004) (CD-ROM), 8 Pages, 2004/11
Linear properties and nonlinear evolutions of an energetic-ion driven instability in a JT-60U plasma were investigated using a simulation code for MHD and energetic particles. The spatial profile of the unstable mode peaks near the plasma center where the safety factor profile is flat. The real frequency of the mode is close to the experimental starting frequency of the fast frequency sweeping mode. The simulation results demonstrate that the energetic ion orbit width and the energetic ion pressure significantly broaden radial profile of the unstable mode. For the experimental condition of JT-60U, the energetic ions broaden the spatial profile of the unstable mode by a factor of 3. The unstable mode is primarily induced by the energetic particles. It is demonstrated that the frequency shifts both upward and downward in the nonlinear evolution at the rate close to that of the fast frequency sweeping mode. In addition to the energetic particle mode in JT-60U, an investigation of TAE in an LHD-like plasma using the simulation code for the helical coordinate system is reported.
Ishikawa, Masao; Kusama, Yoshinori; Takechi, Manabu; Nishitani, Takeo; Morioka, Atsuhiko; Sasao, Mamiko*; Isobe, Mitsutaka*; Krasilnikov, A.*; Kaschuck, Y. A.*
Review of Scientific Instruments, 75(10), p.3643 - 3645, 2004/10
Times Cited Count：6 Percentile：35.7(Instruments & Instrumentation)Measurement of energy distribution of charge exchange neutral particles by using Natural Diamond Detector (NDD) has been started on the JT-60U Tokamak. Because the NDD is sensitive to neutrons and -rays too, the radiation shield has been set up around the NDD. Then energy distribution of neutral particles corresponding to injected neutral beam energy are successfully obtained. Also, enhance of neutral particle flux due to sawtooth oscillation and Alfven Eigenmode induced by N-NBI was observed. The performance of the NDD as CX neutral particle analyzer under the DD neutron filed was demonstrated on JT-60U.
Kishimoto, Yasuaki; Masaki, Tomohiro*; Tajima, Toshiki*
Physics of Plasmas, 9(2), p.589 - 601, 2002/02
Times Cited Count：85 Percentile：91.1(Physics, Fluids & Plasmas)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：90.44(Physics, Fluids & Plasmas)no abstracts in English
Kusama, Yoshinori; Kimura, Haruyuki; Nemoto, Masahiro; Hamamatsu, Kiyotaka; Tobita, Kenji; Oikawa, Toshihiro; Afanassiev, V. I.*; Morioka, Atsuhiko; Fujita, Takaaki; Koide, Yoshihiko; et al.
Plasma Physics and Controlled Fusion, 41(5), p.625 - 643, 1999/00
Times Cited Count：5 Percentile：20.12(Physics, Fluids & Plasmas)no abstracts in English
n eigenmodes and their impact on plasma characteristics in JT-60UKusama, Yoshinori; Nazikian, R.*; Kramer, G. J.*; Kimura, Haruyuki; Saigusa, Mikio*; Ozeki, Takahisa; Fu, G. Y.*; Tobita, Kenji; Oikawa, Toshihiro; Shinohara, Koji; et al.
Fusion Energy 1998, 2, p.537 - 544, 1998/10
no abstracts in English
Kimura, Haruyuki; Moriyama, Shinichi; Saigusa, Mikio; Kusama, Yoshinori; Ozeki, Takahisa; Kramer, G. J.*; Fujita, Takaaki; Oikawa, Toshihiro; Fujii, Tsuneyuki; Nemoto, Masahiro; et al.
Fusion Energy 1996, Vol.3, p.295 - 305, 1997/00
no abstracts in English
Konovalov, S.*; Takizuka, Tomonori; Tani, Keiji; Hamamatsu, Kiyotaka; Azumi, Masafumi
JAERI-Research 94-033, 25 Pages, 1994/11
JAERI-Research-94-033.pdf:0.95MB
no abstracts in English
Tanaka, Ryuichi; Kamiya, Tomihiro
Nuclear Instruments and Methods in Physics Research B, 79(1), p.432 - 435, 1993/07
Times Cited Count：7 Percentile：61.32(Instruments & Instrumentation)no abstracts in English
Kimura, Haruyuki; Fujii, Tsuneyuki; Saigusa, Mikio; Moriyama, Shinichi; Hamamatsu, Kiyotaka; Tobita, Kenji; Nemoto, Masahiro; Kusama, Yoshinori; Sato, Masayasu; Yamagiwa, Mitsuru
Kaku Yugo Kenkyu, 65(SPECIAL ISSUE), p.133 - 161, 1991/03
no abstracts in English
Nishiuchi, Mamiko; Sakaki, Hironao; Pirozhkov, A. S.; Sagisaka, Akito; Kon, Akira; Fukuda, Yuji; Kiriyama, Hiromitsu; Dover, N.*; Sekiguchi, Kentaro; Ogura, Koichi; et al.
no journal, ,
Petawatt class laser systems are in nowadays almost ready to work in all over the world. High energy particles accelerated by the interaction between laser pulses from high intensity laser system and the material shows interesting and particular parameters. Therefore those attract many fields of applications. High contrast and ultra high intensity laser system J-KAREN at KPSI is now under upgrading for achieving highest energy ion beams. No laser system with pulse duration less than 100 fs has demonstrated 100 MeV class proton acceleration in the world. To achieve high energy ions requires higher intensity laser on the target. We report on this presentation the status of the upgrading and the experimental results obtained at the first light experiment.
Asai, Takafumi*; Inoue, Chihiro*; Toyonaga, Keita*; Jinno, Satoshi; Ryazantsev, S.*; Pikuz, T.*; Yamauchi, Tomoya*; Kanasaki, Masato*; Fukuda, Yuji*
no journal, ,
The J-KAREN-P laser at the Kansai Photon Science Institute was irradiated to a cluster target and confirmed the second harmonic generation. Polarization measurements of the generated second harmonic revealed that the polarization plane of the component that passed through the laser-generated plasma was rotated. This result suggests that a vortex-like magnetic field centered on the laser axis is generated.
