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Yoshimura, Kimitaka*; Sakashita, Susumu*; Okubo, Shuichi*; Yamane, Kazunobu*; Seya, Masami
Shadan Hojin Butsuri Tansa Gakkai Dai-115-Kai (Heisei-18-Nendo Shuki) Gakujutsu Koenkai Rombunshu, p.209 - 212, 2006/10
3D MT inversion development has been conducted to solve issues in electromagnetic exploration in the radioactive waste disposal area. Radioactive Waste Management Funding and Research Center (RWMC) operated field work to confirm how the 3D inversion code worked in low resistivity geology at Horonobe area, Hokkaido in 2005 and applied the code to AMT data. Data suggests possibility to estimate salinity of groundwater in the area of lower resistivety than 1ohm-m.
Nagashima, Yoshihiko*; Hoshino, Katsumichi; Nagaoka, Kenichi*; Shinohara, Koji; Fujisawa, Akihide*; Uehara, Kazuya; Kusama, Yoshinori; Ida, Katsumi*; Yoshimura, Yasuo*; Okamura, Shoichi*; et al.
Plasma and Fusion Research (Internet), 1(9), p.041_1 - 041_15, 2006/09
Nonlinear processes between meso-scale structures and turbulent fluctuations in the edge region of the toroidal plasmas were studied using the bispectrum analysis. In the JFT-2M tokamak, divertor plasmas were investigated as well as the limiter plasmas, and the amplitude and phase of the bispectrum function of the potential fluctuation were found to be consistent with an analysis of the drift wave-zonal flow system. In the CHS machine, the edge plasmas during the H-mode were investigated. It was found that the edge potential begins to decrease before the decrease of the intensity of the deuterium line (by about 30ms), and the edge fluctuations are found to be composed of low frequency MHD fluctuations, drift wave like broad band electrostatic fluctuations and high frequency electromagnetic fluctuations. Nonlinear coupling between the MHD fluctuations and the electrostatic fluctuations or the electromagnetic fluctuations were found for the first time.
Nagashima, Yoshihiko*; Ito, Kimitaka*; Ito, Sanae*; Fujisawa, Akihide*; Hoshino, Katsumichi; Nagaoka, Kenichi*; Ejiri, Akira*; Takase, Yuichi*; Yagi, Masatoshi*; Shinohara, Koji; et al.
Europhysics Conference Abstracts (CD-ROM), 30I, 4 Pages, 2006/00
The results of the analyses of nonlinear processes in the plasma in JFT-2M tokamak and CHS machine are reported. In both machines, the measurements of the fluctuations were done by electrostatic probes. The obtained bicoherence and biphase from the potential data in JFT-2M were found to be close to the values obtained from a theoretical model of the interaction of the zonal flow and the drift wave turbulence. Therefore the experimentally obtained nonlinear interaction is considered to be that interaction of the zonal flow and the drift wave turbulence. By the analysis of the CHS H-mode plasma, a marked nonlinear interaction was found between a characteristic MHD magnetic fluctuation and density turbulence. By analysing the cross bispectrum of the density fluctuation and the potential fluctuation, it was found that the fluctuating particle flux is affected by the MHD oscillation. As stated above, we progressed in the investigation of the nonlinear processes of the edge plasmas.
Nagashima, Yoshihiko*; Hoshino, Katsumichi; Shinohara, Koji; Uehara, Kazuya; Kusama, Yoshinori; Nagaoka, Kenichi*; Fujisawa, Akihide*; Ida, Katsumi*; Yoshimura, Yasuo*; Okamura, Shoichi*; et al.
no journal, ,
We present an invited talk on the experimental study of the nonlinear interaction processes of the edge plasma turbulence studied in the JFT-2M tokamak machine of JAEA and in the CHS helical machine of the NIFS. We made a progress in understanding the nonlinear interaction of the drift wave turbulence and the zonal flow by measuring the potential fluctuations and density fluctuations by the measurement of the electrostatic probes. We found that the measured indices such as the bicoherence or the biphase are consistent with the results of a theoretical study of the drift-wave-zonal-flow system for the first time. We also made the convergence characteristic of these indices clear against the realization numbers for the first time. The study progresses the understanding of the plasma turbulence and structural formation in the plasma, and the results contributes much to the understanding of the transport process in the plasma.
Kawata, Tomio; Tsuboya, Takao*; Tanabe, Hiromi*; Yoshimura, Kimitaka*; Asano, Eiichi*; Ouchi, Jin*
no journal, ,
no abstracts in English
Yoshimura, Kimitaka*; Okazaki, Koji*; Osato, Kazumi*; Nakashima, Satoshi*; Osawa, Kenji*; Yabuuchi, Satoshi; Yamanaka, Yoshiaki; Shigeta, Naotaka
no journal, ,
no abstracts in English
Yoshimura, Kimitaka*; Okazaki, Koji*; Osato, Kazumi*; Osawa, Kenji*; Yamaoka, Masanobu*; Nakashima, Satoshi*; Shigeta, Naotaka; Yabuuchi, Satoshi; Yamanaka, Yoshiaki*
no journal, ,
no abstracts in English
Osato, Kazumi*; Yamaoka, Masanobu*; Nakashima, Satoshi*; Yoshimura, Kimitaka*; Okazaki, Koji*; Shigeta, Naotaka; Yabuuchi, Satoshi; Yamanaka, Yoshiaki*
no journal, ,
no abstracts in English
Sakashita, Susumu*; Konishi, Chisato*; Yoshimura, Kimitaka*; Okazaki, Koji*; Shigeta, Naotaka; Yabuuchi, Satoshi; Yamanaka, Yoshiaki*
no journal, ,
no abstracts in English
Yoshimura, Kimitaka*; Wakamatsu, Hisanori*; Ando, Kenichi*; Hashimoto, Shuji*; Yabuuchi, Satoshi; Shigeta, Naotaka
no journal, ,
no abstracts in English
Suzuki, Koichi*; Yoshimura, Kimitaka*; Sugita, Yutaka; Ando, Makoto*; Azuma, Hiroyuki*
no journal, ,
One of the benefits of geophysical exploration is that extensive and continuous surveys are possible at low cost, however, the obtained physical properties are chiefly velocity of elastic wave and electrical resistivity. Therefore, it is very important that the techniques can convert geophysical data into quantitative information on the geological environment required for engineering technology. In this study, we have applied an approach that provides estimates of porosity, clay content, and equivalent NaCl concentration based on a combined interpretation of geophysical survey data utilizing an expanded bimodal mixture model. The study used seismic velocity and electrical conductivity data obtained from geophysical logging at two soft sedimentary rock sites, in the muddy or tuffaceous sandstone and mudstone at Yokosuka, and in diatomaceous mudstone and fine sandstone at Horonobe, Japan. The geological information for these sites was successfully estimated.
