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Nagano, Hirohiko*; Atarashi-Andoh, Mariko; Tanaka, Sota*; Yomogida, Takumi; Kozai, Naofumi; Koarashi, Jun
Frontiers in Forests and Global Change (Internet), 6, p.1228053_1 - 1228053_9, 2023/00
Times Cited Count:2 Percentile:26.05(Ecology)Fujita, Hirohiko*; Fujita, Yoshitaka*; Utsuno, Yutaka; Yoshida, Kenichi*; Adachi, Tatsuya*; Algora, A.*; Csatls, M.*; Deaven, J. M.*; Estevez-Aguado, E.*; Guess, C. J.*; et al.
Physical Review C, 100(3), p.034618_1 - 034618_13, 2019/09
Times Cited Count:15 Percentile:79.26(Physics, Nuclear)no abstracts in English
Strasser, P.*; Abe, Mitsushi*; Aoki, Masaharu*; Choi, S.*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; et al.
EPJ Web of Conferences, 198, p.00003_1 - 00003_8, 2019/01
Times Cited Count:13 Percentile:98.52(Quantum Science & Technology)Asakura, Nobuyuki; Shinya, Kichiro*; Tobita, Kenji; Hoshino, Kazuo; Shimizu, Katsuhiro; Uto, Hiroyasu; Someya, Yoji; Nakamura, Makoto; Ono, Noriyasu*; Kobayashi, Masahiro*; et al.
Fusion Science and Technology, 63(1T), p.70 - 75, 2013/05
Times Cited Count:14 Percentile:70.26(Nuclear Science & Technology)Design study of poloidal field coil (PFC) locations and current distribution for the advanced divertor in the Demo tokamak reactor was presented. Concept of the super-X divertor (SXD) for Demo reactor has an outer divertor leg longer than the conventional divertor, and it extends outboard to increase both the target wetted area and connection length to the outer target (). Equilibrium calculation code, TOSCA, was developed by introducing two parameters, i.e. super-X null radius (
) and a ratio of the poloidal flux at the super-X null to that at the separatrix (
). Some SXD magnetic configurations with minimal number of PFCs located outside toroidal field coil (TFC) were Demonstrated. Locations of the divertor target were also investigated. It was found that the flux expansion can be increased up to 4-10 depending on the target location and
, and that SXD has an advantage to increase
with
. Thus, the divertor plasma temperature is expected to decrease at the same upstream plasma density. On the other hand, large currents for the divertor PFCs were necessary. Other arrangements of PFCs such as (1) larger
and (2) inside TFC, can reduce the PFC currents.
Asakura, Nobuyuki; Shinya, Kichiro*; Tobita, Kenji; Hoshino, Kazuo; Shimizu, Katsuhiro; Uto, Hiroyasu; Someya, Yoji; Nakamura, Makoto; Ono, Noriyasu*; Kobayashi, Masahiro*; et al.
Fusion Science and Technology, 63(1T), p.70 - 75, 2013/05
no abstracts in English
Asakura, Nobuyuki; Ono, Noriyasu*; Tanaka, Hirohiko*; Kawashima, Hisato; Nakano, Tomohide
Journal of Nuclear Materials, 390-391, p.364 - 367, 2009/06
Times Cited Count:4 Percentile:29.73(Materials Science, Multidisciplinary)Characteristics of the fluctuations at three locations (Low-Field-Side midplane, X-point, and High-Field-Side SOLs) of the JT-60U SOL were investigated in L-mode and ELMy H-mode plasmas. Influence of their poloidal asymmetry at the LFS and HFS on the parallel plasma flow was investigated. For the L-mode, poloidal asymmetry in djs/js
was enhanced at the LFS midplane (40-60%), while it was small (10-20%) at the HFS SOL and LFS X-point. On the other hand, djs/
js
was similar (20-30
) for the ELMy H-mode. Statistical properties (Skewness) and their poloidal asymmetry were different in the ELMy H-mode and L-mode plasmas. In the ELMy H-mode, positive S (= 0.3-0.5) was seen near the separatrix. However, in the L-mode, larger S (=0.5-0.9) was observed at the LFS midplane, and it extended to the far SOL (r
10 cm). In-out asymmetry in the intermittent transport will contribute to produce the SOL flow pattern.
Tanaka, Hirohiko*; Ono, Noriyasu*; Asakura, Nobuyuki; Tsuji, Yoshiyuki*; Kawashima, Hisato; Takamura, Shuichi*; Uesugi, Yoshihiko*; JT-60U Team
Nuclear Fusion, 49(6), p.065017_1 - 065017_7, 2009/06
Times Cited Count:38 Percentile:78.69(Physics, Fluids & Plasmas)Comparison between fluctuation characteristics at high-field-side (HFS) and low-field-side (LFS) scrape off layers (SOLs) has been made, for the first time, in the L mode plasma of the JT-60U tokamak using reciprocating Langumuir probes. Statistical analysis based on probability distribution function (PDF) was employed to describe intermittent (non-diffusion) transport in SOL plasma fluctuations. The positive bursty events appeared most frequently at LFS midplane associated with blobby plasma transport, then the PDF is strongly skewed positively, while the PDF in HFS SOL is close to Gaussian distribution. Conditional averaging analysis of the positive bursty events at LFS midplane indicates the intermittent feature with a rapid increase and a slow decay is similar to that of plasma blobs theoretically predicted. Statistical self-similarity was also investigated with Fourier power spectrum and statistics of waiting-time and duration-time of the fluctuation.
Iwase, Hiroki; Koizumi, Satoshi; Suzuki, Junichi; Oku, Takayuki; Sasao, Hajime*; Tanaka, Hirokazu*; Shimizu, Hirohiko*; Hashimoto, Takeji
Journal of Applied Crystallography, 40(s1), p.s414 - s417, 2007/04
Times Cited Count:17 Percentile:81.99(Chemistry, Multidisciplinary)In order to extend an upper q-limit larger, high-angle He sub-detectors were installed on focusing and polarized neutron small-angle scattering spectrometer (SANS-J-II) at JRR-3, Tokai. Consequently, its upper q-limit was improved from 0.2 to 2
. To quantitatively discriminate spin incoherent scattering from hydrogen or to perform nuclear spin polarization contrast variation, a remanent supermirror analyser is also available on the high-angle sub detector. By combining a focusing ultra-small angle scattering, realized by compound and/or magnetic lens and high resolution area detector, SANS-J-II is able to cover from 3
10
to 2
(four order of magnitude of q), which profits to investigate hierarchically ordered system, found widely in hard, soft and bio-materials.
Koizumi, Satoshi; Iwase, Hiroki; Suzuki, Junichi; Oku, Takayuki; Motokawa, Ryuhei; Sasao, Hajime*; Tanaka, Hirokazu; Yamaguchi, Daisuke; Shimizu, Hirohiko; Hashimoto, Takeji
Physica B; Condensed Matter, 385-386(2), p.1000 - 1006, 2006/11
Times Cited Count:41 Percentile:81.00(Physics, Condensed Matter)no abstracts in English
Koizumi, Satoshi; Iwase, Hiroki; Tanaka, Hirokazu; Hashimoto, Takeji; Suzuki, Junichi; Oku, Takayuki; Sasao, Hajime*; Shimizu, Hirohiko
Hamon, 14(4), p.266 - 274, 2004/10
no abstracts in English
Yamamoto, Tomoyuki*; Mizoguchi, Teruyasu*; Tatsumi, Kazuyoshi*; Tanaka, Isao*; Adachi, Hirohiko*; Muramatsu, Yasuji; Gullikson, E. M.*; Perera, R. C. C.*
Materials Transactions, 45(7), p.1991 - 1993, 2004/07
Times Cited Count:7 Percentile:44.11(Materials Science, Multidisciplinary)First principles calculations have been carried out to investigate the core-hole effects on the theoretical fine structures of the X-ray absorption spectra of MgF and ZnF
ath FK-edge. Experimental profiles of the near-edge X-ray absorption fine structures are well reproduced by the theoretical calculations when the core-hole effect is introduced. The dependence of supercell size on the theoretical fine structures is also examined.
Kawabata, Takahiro*; Ishikawa, Takatsugu*; Ito, M.*; Nakamura, M.*; Sakaguchi, Harutaka*; Takeda, H.*; Taki, T.*; Uchida, Makoto*; Yasuda, Yusuke*; Yosoi, Masaru*; et al.
Physical Review C, 65(6), p.064316_1 - 064316_12, 2002/06
Times Cited Count:20 Percentile:69.72(Physics, Nuclear)no abstracts in English
Kawabata, Takahiro*; Akimune, Hidetoshi*; Fujimura, Hisako*; Fujita, Hirohiko*; Fujita, Yoshitaka*; Fujiwara, Mamoru; Hara, Keigo*; Hatanaka, Kichiji*; Hosono, K.*; Ishikawa, Takatsugu*; et al.
Nuclear Instruments and Methods in Physics Research A, 459(1-2), p.171 - 176, 2001/02
Times Cited Count:17 Percentile:74.32(Instruments & Instrumentation)no abstracts in English
Nagano, Hirohiko; Tanaka, Sota; Atarashi-Andoh, Mariko; Koarashi, Jun
no journal, ,
Soil organic carbon (SOC) is a key component in global carbon cycling, while water-extractable organic carbon (WEOC) in soils is a proxy of soil carbon available to the living microbial community. Volcanic ash soils, a soil type dominant in Japan, are known to have a very high ability to stabilize soil carbon, and SOC content often correlates with phosphate absorption coefficients (PAC) in soils. In this study, we compared the SOC-PAC relationship and the WEOC-PAC relationships using 42 volcanic ash soils (0-6 cm depth) collected from a Japanese temperate forest. SOC showed a very strong correlation with PAC (r = 0.72). Correlation between SOC and WEOC was also strong (r = 0.84). Correlation between WEOC and PAC was, however, weak (r = 0.42). Thus, water destabilized carbon likely originated from residual carbon sources other than the primary carbon that is highly stabilized in volcanic ash soils.
Tanaka, Sota; Nagano, Hirohiko*; Atarashi-Andoh, Mariko; Koarashi, Jun
no journal, ,
no abstracts in English
Nagano, Hirohiko*; Tanaka, Sota*; Atarashi-Andoh, Mariko; Koarashi, Jun
no journal, ,
no abstracts in English
Tanaka, Sota; Nagano, Hirohiko; Atarashi-Andoh, Mariko; Koarashi, Jun
no journal, ,
no abstracts in English
Tanaka, Sota*; Nagano, Hirohiko*; Atarashi-Andoh, Mariko; Takakai, Fumiaki*; Sato, Takashi*; Koarashi, Jun
no journal, ,
no abstracts in English
Tanaka, Hirohiko*; Ono, Noriyasu*; Asakura, Nobuyuki; Tsuji, Yoshiyuki*; Kajita, Shin*
no journal, ,
We have investigated fast temporal electrostatic fluctuations measured in detached SOL/divertor plasmas of JT-60U. Application of statistical analysis techniques clarified that fluctuations of ion saturation current measured around X-point had a number of positive spikes under the detached condition, but not under the attached condition. This result suggests that an intermittent phenomenon occurred near the detached divertor leg would generate blob-like structures in divertor region. In this presentation, we will show the results obtained by using several analysis techniques (e.g. spectral analysis, conditional averaging, and so on). After that, we will compare the results between under the detached and attached condition.
Nagano, Hirohiko*; Atarashi-Andoh, Mariko; Tanaka, Sota*; Koarashi, Jun
no journal, ,