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Aritomo, Yoshihiro*; Amano, Shota*; Okubayashi, Mizuki*; Yanagi, Baku*; Nishio, Katsuhisa; Ota, Masahisa*
Physics of Atomic Nuclei, 83(4), p.545 - 549, 2020/07
Times Cited Count：0 Percentile：0.02(Physics, Nuclear)Niwa, Masakazu; Nomura, Katsuhiro; Hiura, Yuki
JAEA-Review 2018-010, 40 Pages, 2018/04
JAEA-Review-2018-010.pdf:6.11MB
JAEA-Review-2018-010-appendix(CD-ROM).zip:36.31MB
In the Japanese Islands, coastal area can be proposed as an investigation site for geological disposal of high-level radioactive wastes. For an assessment of fault activity in coastal area, offshore surveys such as acoustic profiling and boring should be examined as well as inland surveys. In addition, adequate understanding spatial distributions and characteristics of faults in the coastal area of Japan will contribute to safety assessment for the geological disposal in such area. In this report, we collected and compiled previous studies focused on spatial distribution, continuity, timing of displacement and recurrence interval of faults near coastline, specifically faults along or across a boundary between land and sea, and technologies of survey and assessment for them.
Oikawa, Toshihiro; Suzuki, Takahiro; Isayama, Akihiko; Hayashi, Nobuhiko; Fujita, Takaaki; Naito, Osamu; Tsuda, Takashi; Kurita, Genichi; JT-60 Team
Nuclear Fusion, 45(9), p.1101 - 1108, 2005/09
Times Cited Count：4 Percentile：14.23(Physics, Fluids & Plasmas)Evolution of the current density profile associated with magnetic island formation in a neoclassical tearing mode plasma was measured for the first time in JT-60U by. As the island grew, the current density profile turned flat at the radial region of the island, followed by an appearance of a hollow structure. As the island shrank, the deformed region became narrower, and it finally diminished after the disappearance of the island. In an MHD-quiescent plasma, on the other hand, no deformation was observed. The observed deformation in the current density profile associated with the tearing mode is reproduced in a time dependent transport simulation assuming reduction of the bootstrap current in the radial region of the island. Comparison of the measurement with a calculated steady-state solution also explains the temporal behaviors of the current density and safety factor profiles with reduction and recovery of the bootstrap current. From the experimental observation and simulations, we reach conclusion that the bootstrap current decreases within the island O-point.
Oikawa, Toshihiro; Isayama, Akihiko; Fujita, Takaaki; Suzuki, Takahiro; Tsuda, Takashi; Kurita, Genichi
Physical Review Letters, 94(12), p.125003_1 - 125003_4, 2005/04
Times Cited Count：10 Percentile：53.4(Physics, Multidisciplinary)Evolution of the current density profile associated with the magnetic island formation during a tearing mode was measured for the first time in the JT-60U tokamak. With the island growth, the current density profile turned flat at the radial region of the island, followed by appearance of a hollow structure. As the island shrank, the flat region became narrower, and it finally diminished after disappearance of the island. It was also observed that the local poloidal magnetic field fluctuated in correlation with the island rotation. This indicates that the observed deformation in the current density profile is localized in the O-point of the island. The result is the first experimental demonstration of theoretical predictions on the current density evolution in tearing modes.
gas under 1000 K by synchrotron radiation photoemission spectroscopyYoshigoe, Akitaka; Moritani, Kosuke; Teraoka, Yuden
Surface Science, 566-568(Part.2), p.1124 - 1129, 2004/09
Times Cited Count：5 Percentile：29.73(Chemistry, Physical)The Si(001) oxidaion is an important reaction for not only semiconductor technology but also surface science. It is known that the growth mode forming oxide-layers is divided into two regions depending on surface temperature conditions. One is passive oxidation and the other is two dimensional island growth including SiO desorption. Since the oxygen uptake measurements have been measured in many reported studies, Si oxidatuion states related to the growth of oxide-layers have not been clarified yet. In order to measure the time evolution of Si oxidation states depending on the surface temperature, we have performed the real-time photoemission measurements using synchrotron radiation at SUREAC2000 in SPring-8 . We found that the Si
states was formed at the early oxidation stage in the two dimiensional island regions.
Konovalov, S. V.; Mikhailovskii, A. B.*; Kovalishen, E. A.*; Kamenets, F. F.*; Ozeki, Takahisa; Shirokov, M. S.*; Takizuka, Tomonori; Tsypin, V. S.*
Doklady Physics, 49(7), p.405 - 408, 2004/07
Times Cited Count：1 Percentile：11.77(Mechanics)Effect of feedback system, placed outside the vacuum vessel, on neoclassical tearing modes (NTMs) in tokamaks is analytically studied. External matching parameters for magnetic island chain are derived for the simplest case of step profile of equilibrium parallel current. The structure of dynamical equations for the island width and island rotation frequency in terms of matching parameters is explained. It is shown that such a feedback system can lead to essential shift of the island rotation, in particular, for stabilization of NTMs by the polarization current effect.
Mikhailovskii, A. B.*; Kovalishen, E. A.*; Shirokov, M. S.*; Konovalov, S. V.; Tsypin, V. S.*; Kamenets, F. F.*; Ozeki, Takahisa; Takizuka, Tomonori
Physics of Plasmas, 11(2), p.666 - 676, 2004/02
Times Cited Count：6 Percentile：20(Physics, Fluids & Plasmas)Analytical treatment of magnetic islands with high poloidal mode numbers and widths smaller than ion Larmor radius (microislands) is presented. The profile functions and rotation frequencies of microislands are investigated with the two-fluid magnetohydrodynamics. The microislands are described in terms of two profile functions, one of which characterizes the electric field and perturbed plasma density, and second the perturbed electron temperature. The problem of rotation frequencies of microislands is discussed.
Nishizawa, Masato*; Chino, Masamichi
Taiki Kankyo Gakkai-Shi, 39(1), p.31 - 42, 2004/01
no abstracts in English
Konovalov, S. V.; Mikhailovskii, A. B.*; Tsypin, V. S.*; Kovalishen, E. A.*; Shirokov, M. S.*; Ozeki, Takahisa; Takizuka, Tomonori
Physics Letters A, 318(4-5), p.429 - 434, 2003/11
Times Cited Count：7 Percentile：46.48(Physics, Multidisciplinary)no abstracts in English
Takizuka, Tomonori
Purazuma, Kaku Yugo Gakkai-Shi, 78(12), p.1282 - 1284, 2002/12
An idea of a new equilibrium of a strongly-reversed-shear tokamak plasma with a current hole is proposed. This equilibrium configuration called "Axisymmetric Tri-Magnetic-Islands (ATMI) equilibrium" has three islands, a central-negative-current island and side-positive-current islands, along the R direction and two x-points along the Z direction. The equilibrium is stable with the elongation coils when the current in the ATMI region is limited small.
Furuno, Akiko; Nagai, Haruyasu; Umeyama, Nobuaki; Chino, Masamichi
Taiki Kankyo Gakkai-Shi, 37(1), p.23 - 34, 2002/01
The active volcano Oyama in the Miyake Island has been emitting a huge amount of volcanic gases since the first eruption in July 2000. High concentrations of SO2 gas originated in Oyama frequently appear in the wide area from the northeast to the west part of Honshu, Japan. This paper describes real-time prediction of SO2 dispersion covering the Tokai and Kanto District and its verification by comparing with SO2 observation data from October to November 2000. Atmospheric dispersions of SO2 are calculated by using our software system that combines a regional atmospheric dynamic model and a particle random walk model. It was proved that the real-time prediction of our system has adequate precision. The importance of including the effect of wet deposition was also shown. The release amounts estimated from the comparison between the calculation result and the monitoring data are 20,000 - 50,000 ton/day, which is consistent to measured ones at the Miyake Island.
Tokuda, Shinji; Higuchi, Takatoshi*; Suzuki, Noriyuki*
Purazuma, Kaku Yugo Gakkai-Shi, 77(12), p.1180 - 1220, 2001/12
no abstracts in English
Ozeki, Takahisa; Isayama, Akihiko
Purazuma, Kaku Yugo Gakkai-Shi, 77(5), p.409 - 419, 2001/05
Neoclassical tearing modes (NTMs) which are induced by lack of the bootstrap current inside the magnetic island are reviewed based on the modified Rutherford equation. Theoretical bases and experimental observations of NTM are described. The beta value scaling of the growth of NTM and the mechanism of the growth are discussed. Influence of NTM on energy confinement is described, and the stabilization of NTM by electron cyclotron current drive (ECCD) is introduced.
Nagai, Haruyasu; Furuno, Akiko; Terada, Hiroaki; Umeyama, Nobuaki; Yamazawa, Hiromi; Chino, Masamichi
JAERI-Research 2001-012, 28 Pages, 2001/03
JAERI-Research-2001-012.pdf:1.77MB
Japan Atomic Energy Research Institute is advancing the study for prediction of material circulation in the environment to cope with environmental pollution, based on SPEEDI (System for Prediction of Environmental Emergency Dose Information) and WSPEEDI (Worldwide version of SPEEDI), which are originally developed aiming at real-time prediction of atmospheric dispersion of radioactive substances accidentally released from nuclear facility. As a part of this study, dispersion simulation of volcanic gas erupted from Miyake Island is put into practice. After the stench incident at the west Kanto District on 28 August 2000 caused by volcanic gas from Miyake Island, simulations dealing with atmospheric dispersion of volcanic gas from Miyake Island have been carried out. This report describes the details of these studies.
Ishizawa, Akihiro; Tokuda, Shinji
Physics of Plasmas, 7(3), p.875 - 882, 2000/03
Times Cited Count：14 Percentile：41.82(Physics, Fluids & Plasmas)no abstracts in English
Kobayashi, M.*; Tsuda, Takashi; Tashiro, Kenji*; Kojima, H.*; Zhai, K.*; Takamura, Shuichi*
Nuclear Fusion, 40(2), p.181 - 193, 2000/02
Times Cited Count：27 Percentile：63.03(Physics, Fluids & Plasmas)no abstracts in English
Ishida, Shinichi; Isei, Nobuaki; Sato, Masayasu
JAERI-M 92-111, 19 Pages, 1992/08
no abstracts in English
Yoshida, H.; ;
Japanese Journal of Applied Physics, 21(7), p.1068 - 1074, 1982/00
Times Cited Count：1 Percentile：12.39(Physics, Applied)no abstracts in English
Yoshida, H.; ; ; Sengoku, Seio; ; ; ;
JAERI-M 9789, 28 Pages, 1981/11
no abstracts in English
; ; ; ; Tsunematsu, Toshihide; ; ; Takeda, Tatsuoki
JAERI-M 9788, 17 Pages, 1981/11
no abstracts in English
