研究者詳細 - 大野　哲靖

論文 - 大野　哲靖

分割表示 657 件中 141 - 160 件目／全件表示 >>

Measurement of He neutral temperature in detached plasmas using laser absorption spectroscopy 査読有り

Aramaki M., Tsujihara T., Kajit S., Tanaka H., Ohno N.

AIP Advances 8 巻 ( 1 ) 頁： 015308 2018年1月

Analysis of ELM stability with extended MHD models in JET, JT-60U and future JT-60SA tokamak plasmas 査読有り

Aiba N., Pamela S., Honda M., Urano H., Giroud C., Delabie E., Frassinetti L., Lupelli I., Hayashi N., Huijsmans G.T.A., Litaudon X., Abduallev S., Abhangi M., Abreu P., Afzal M., Aggarwal K.M., Ahlgren T., Ahn J.H., Aho-Mantila L., Airila M., Albanese R., Aldred V., Alegre D., Alessi E., Aleynikov P., Alfier A., Alkseev A., Allinson M., Alper B., Alves E., Ambrosino G., Ambrosino R., Amicucci L., Amosov V., Sundén E.A., Angelone M., Anghel M., Angioni C., Appel L., Appelbee C., Arena P., Ariola M., Arnichand H., Arshad S., Ash A., Ashikawa N., Aslanyan V., Asunta O., Auriemma F., Austin Y., Avotina L., Axton M.D., Ayres C., Bacharis M., Baciero A., Baião D., Bailey S., Baker A., Balboa I., Balden M., Balshaw N., Bament R., Banks J.W., Baranov Y.F., Barnard M.A., Barnes D., Barnes M., Barnsley R., Wiechec A.B., Orte L.B., Baruzzo M., Basiuk V., Bassan M., Bastow R., Batista A., Batistoni P., Baughan R., Bauvir B., Baylor L., Bazylev B., Beal J., Beaumont P.S., Beckers M., Beckett B., Becoulet A., Bekris N., Beldishevski M., Bell K., Belli F., Bellinger M., Belonohy , Ayed N.B., Benterman N.A., Bergsåker H., Bernardo J., Bernert M., Berry M., Bertalot L., Besliu C., Beurskens M.

Plasma Physics and Controlled Fusion 60 巻 ( 1 ) 2018年1月

記述言語：日本語出版者・発行元：Plasma Physics and Controlled Fusion

The stability with respect to a peelingballooning mode (PBM) was investigated numerically with extended MHD simulation codes in JET, JT-60U and future JT-60SA plasmas. The MINERVA-DI code was used to analyze the linear stability, including the effects of rotation and ion diamagnetic drift (w∗i), in JET-ILW and JT-60SA plasmas, and the JOREK code was used to simulate nonlinear dynamics with rotation, viscosity and resistivity in JT-60U plasmas. It was validated quantitatively that the ELM trigger condition in JET-ILW plasmas can be reasonably explained by taking into account both the rotation and w∗i effects in the numerical analysis. When deuterium poloidal rotation is evaluated based on neoclassical theory, an increase in the effective charge of plasma destabilizes the PBM because of an acceleration of rotation and a decrease in w∗i. The difference in the amount of ELM energy loss in JT-60U plasmas rotating in opposite directions was reproduced qualitatively with JOREK. By comparing the ELM affected areas with linear eigenfunctions, it was confirmed that the difference in the linear stability property, due not to the rotation direction but to the plasma density profile, is thought to be responsible for changing the ELM energy loss just after the ELM crash. A predictive study to determine the pedestal profiles in JT-60SA was performed by updating the EPED1 model to include the rotation and w∗i effects in the PBM stability analysis. It was shown that the plasma rotation predicted with the neoclassical toroidal viscosity degrades the pedestal performance by about 10% by destabilizing the PBM, but the pressure pedestal height will be high enough to achieve the target parameters required for the ITER-like shape inductive scenario in JT-60SA.

DOI： 10.1088/1361-6587/aa8bec

Scopus

Enhanced growth of large-scale nanostructures with metallic ion precipitation in helium plasmas 査読有り

Shin Kajita, Shota Kawaguchi, Noriyasu Ohno, Naoaki Yoshida

Scientific Reports 8 巻頁： 56 2018年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Nature Publishing Group

Helium plasma irradiation on metal surfaces leads to the formation of metallic fuzzy nanostructures accompanied by the growth of helium bubbles in metals. The mechanism of the growth process, its impact for fusion devices, and potential application have been explored. Here we show enhanced growth of large-scale fuzz by precipitating additional metallic particles during helium plasma irradiation. The growth rate of the fuzzy structures became orders of magnitude greater than conventional fuzz growth
in an hour of irradiation, 1 mm-thick visible tungsten and molybdenum fuzzy fur structures covered a tungsten metal substrate. Additional precipitation of metallic ions breaks the bottleneck diffusion process
moreover, further acceleration in the growth rate could have occurred if the electric sheath shape was influenced by the grown structure and the electric field that formed around the structure started collecting ions.

DOI： 10.1038/s41598-017-18476-7

Web of Science

Scopus

Morphology Changes of Platinum and Tungsten Carbide by He Plasma Irradiation 査読有り

Tomita Yudai, Kajita Shin, Ohno Noriyasu, Tanaka Hirohiko, Ichino Yusuke

PLASMA AND FUSION RESEARCH 13 巻頁： 3406074 2018年

Recent progress of divertor simulation research using the GAMMA 10/PDX tandem mirror 査読有り

Nakashima Y, Ichimura K, Islam M. S, Sakamoto M, Ezumi N, Hirata M, Ichimura M, Ikezoe R, Imai T, Kariya T, Katanuma I, Kohagura J, Minami R, Numakura T, Yoshikawa M, Iijima T, Islam M. M, Nojiri K, Shimizu K, Terakado A, Togo S, Asakura N, Fukumoto M, Hatayama A, Hirooka Y, Kado S, Kubo H, Masuzaki S, Matsuura H, Nakano T, Nagata S, Nishino N, Ohno N, Sagara A, Sawada K, Shoji M, Tonegawa A, Ueda Y

NUCLEAR FUSION 57 巻 ( 11 ) 2017年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Nuclear Fusion

This paper describes the recent progress in divertor simulation research using the GAMMA 10/PDX tandem mirror towards the development of divertors in fusion reactors. During a plasma flow generation experiment in the end cell of the GAMMA 10/PDX, ICRF heating in the anchor cell successfully extended the particle flux up to 3.3 1023 m2 s-1. Superimposing the short pulse of the ECH also attained a maximum heat flux of ∼30 MW m-2. We have succeeded in achieving and characterizing the detachment of the high-temperature plasma, which is equivalent to the SOL plasma of tokamaks, by using the divertor simulation experimental module (D-module) in the GAMMA 10/PDX end cell, in spite of using a linear device with a short magnetic field line connection length. Various gases (Ar, Xe, Ne and N2) are examined to evaluate the effect of radiation cooling against the plasma flow at the MW m-2 level in the divertor simulation region and the following results are obtained: (i) Xe gas was most effective in the reduction of heat and particle fluxes (1%, 3%, respectively) and has a stronger effect on electron cooling (down to ∼1.6 eV) in the used gas species. (ii) Ne gas was less effective. On the other hand, (iii) N2 gas showed more favorable effects than Ar in the lower pressure range. These results will contribute to the progress in detached plasma operation and in clarifying the radiation cooling mechanism towards the development of future divertors.

DOI： 10.1088/1741-4326/aa7cb4

Web of Science

Scopus

Development of a Compact Divertor Plasma Simulator for Plasma-Wall Interaction Studies on Neutron-Irradiated Materials 査読有り

N.Ohno, T.Kuwabara, M.Takagi, R.Nishimura, M.Yajima, A.Sagara, T.Toyama, K.Suzuki, H.Kurishita, T.Shikama, Y.Hatano, N.Yoshida

PLASMA AND FUSION RESEARCH 12 巻 ( 0 ) 頁： 1405040 - 1405040 2017年10月

担当区分：筆頭著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：社団法人プラズマ・核融合学会

We have developed a compact divertor plasma simulator (CDPS) that can produce steady-state deuterium and/or helium plasmas with densities above ∼ 1018 m−3 for Plasma-Wall Interaction (PWI) studies of neutronirradiated materials. The maximum particle flux is about 1022 m−2s−1. The CDPS was installed and is being operated in the radiation-controlled area of the International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University. We are able to control sample temperature within uncertainty of 5◦C during plasma exposure by adjusting the cooling air flow rate to the sample holder. The CDPS has a sample-carrier system, which makes it possible to transfer a plasma-irradiated sample from the sample holder to an infrared heater for analysis using thermal desorption spectroscopy (TDS) without exposing it to the air. This avoids the oxidation of the sample and minimizes the time between the end of plasma exposure and TDS analysis. An ITER-like tungsten (W) sample (A.L.M.T. Corp.), which has been irradiated by neutrons to 0.06 dpa in a fission reactor, was exposed to a deuterium plasma in the CDPS. The experimental results clearly show that the total deuterium retention in the neutron-irradiated W sample increases significantly in comparison with a pristine W, as demonstrated by broadening of the TDS spectrum at high temperatures.

DOI： 10.1585/pfr.12.1405040

Web of Science

Scopus

Studies of power exhaust and divertor design for a 1.5 GW-level fusion power DEMO 査読有り

N.Asakura, K.Hoshino, S.Suzuki, S.Tokunaga, Y.Someya, H.Utoh, H.Kudo, Y.Sakamoto, R.Hiwatari, K.Tobita, K.Shimizu, K.Ezato, Y.Seki, N.Ohno, Y.Ueda, Joint Special Team for DEMO Design

Nuclear Fusion 57 巻頁： 126050(12 pp) 2017年10月

Plasma Exhaust and Divertor Studies in JA and EU Broader Tokamak Fusion Reactor Approach, DEMO Design Activity 査読有り

Nobuyuki Asakura, Kazuo Hoshino, Hiroyasu Utoh, Yoji Someya, Satoshi Suzuki, Christian Bachmann, Holger Reimerdes, Hironobu Kudo, Shinsuke Tokunaga, Yuki Homma, Yoshiteru Sakamoto, Ryoji Hiwatari, Ronald Wenninger, Kenji Tobita, Noriyasu Ohno,Gianfranco Federici, Koichiro Ezato, Yohji Seki, Noriyasu Ohno, Yoshio Ueda

2017年9月

Extension of the operational regime of the LHD towards a deuterium experiment 査読有り

Takeiri Y., Morisaki T., Osakabe M., Yokoyama M., Sakakibara S., Takahashi H., Nakamura Y., Oishi T., Motojima G., Murakami S., Ito K., Ejiri A., Imagawa S., Inagaki S., Isobe M., Kubo S., Masamune S., Mito T., Murakami I., Nagaoka K., Nagasaki K., Nishimura K., Sakamoto M., Sakamoto R., Shimozuma T., Shinohara K., Sugama H., Watanabe K. Y., Ahn J. W., Akata N., Akiyama T., Ashikawa N., Baldzuhn J., Bando T., Bernard E., Castejon F., Chikaraishi H., Emoto M., Evans T., Ezumi N., Fujii K., Funaba H., Goto M., Goto T., Gradic D., Gunsu Y., Hamaguchi S., Hasegawa H., Hayashi Y., Hidalgo C., Higashiguchi T., Hirooka Y., Hishinuma Y., Horiuchi R., Ichiguchi K., Ida K., Ido T., Igami H., Ikeda K., Ishiguro S., Ishizaki R., Ishizawa A., Ito A., Ito Y., Iwamoto A., Kamio S., Kamiya K., Kaneko O., Kanno R., Kasahara H., Kato D., Kato T., Kawahata K., Kawamura G., Kisaki M., Kitajima S., Ko W. H., Kobayashi M., Kobayashi S., Kobayashi T., Koga K., Kohyama A., Kumazawa R., Lee J. H., Lopez-Bruna D., Makino R., Masuzaki S., Matsumoto Y., Matsuura H., Mitarai O., Miura H., Miyazawa J., Mizuguchi N., Moon C., Morita S., Moritaka T., Mukai K., Muroga T., Muto S., Mutoh T., Nagasaka T., Nagayama Y., Nakajima N., Nakamura Y., Nakanishi H., Nakano H., Nakata M., Narushima Y., Nishijima D., Nishimura A., Nishimura S., Nishitani T., Nishiura M., Nobuta Y., Noto H., Nunami M., Obana T., Ogawa K., Ohdachi S., Ohno M., Ohno N., Ohtani H., Okamoto M., Oya Y., Ozaki T., Peterson B. J., Preynas M., Sagara S., Saito K., Sakaue H., Sanpei A., Satake S., Sato M., Saze T., Schmitz O., Seki R., Seki T., Sharov I., Shimizu A., Shiratani M., Shoji M., Skinner C., Soga R., Stange T., Suzuki C., Suzuki Y., Takada S., Takahata K., Takayama A., Takayama S., Takemura Y., Takeuchi Y., Tamura H., Tamura N., Tanaka H., Tanaka K., Tanaka M., Tanaka T., Tanaka Y., Toda S., Todo Y., Toi K., Toida M., Tokitani M., Tokuzawa T., Tsuchiya H., Tsujimura T., Tsumori K., Usami S., Velasco J. L., Wang H., Watanabe T. -H., Watanabe T., Yagi J., Yajima M., Yamada H., Yamada I., Yamagishi O., Yamaguchi N., Yamamoto Y., Yanagi N., Yasuhara R., Yatsuka E., Yoshida N., Yoshinuma M., Yoshimura S., Yoshimura Y.

Nuclear Fusion 57 巻 ( 10 ) 2017年8月

Erosion of nanostructured tungsten by laser ablation, sputtering and arcing 査読有り

Dogyun Hwangbo, Shota Kawaguchi, Shin Kajita, Noriyasu Ohno

Nuclear Materials and Energy 12 巻頁： 386 - 391 2017年8月

Measuring temperature effects on nano-bubble growth in tungsten with grazing incidence small angle X-ray scattering 査読有り

Matt Thompson, Russ Doerner, Noriyasu Ohno, Nigel Kirby, Patrick Kluth, Daniel Riley, Cormac Corr

Nuclear Materials and Energy 12 巻頁： 1294 - 1297 2017年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Elsevier Ltd

W samples were exposed to He plasma in the MAGPIE, NAGDIS-II and PISCES-A across a range of sample temperatures between 473–1123 K. GISAXS was used to quantify the effect of plasma fluence and W surface temperature on He nano-bubble size distributions. In NAGDIS-II at 873 K nano-bubbles are exponentially distributed with mean diameters μ=0.64±0.01nm, similar to the value of μ=0.62±0.01nmfound for the MAGPIE plasma device at the much lower temperature of 473 K. Above ∼900 K nano-bubbles followed an approximately exponential distribution with μ &gt
0.72 nm demonstrating a significant increase in nano-bubble sizes at higher temperatures.

DOI： 10.1016/j.nme.2016.11.025

Web of Science

Scopus

A Particle-In-Cell approach to particle flux shaping with a surface mask 査読有り

Kawamura G, Ohno N, Takamura S, Tomita Y

NUCLEAR MATERIALS AND ENERGY 12 巻頁： 297 - 301 2017年8月

Toroidally symmetric/asymmetric effect on the divertor flux due to neon/nitrogen seeding in LHD 査読有り

Tanaka H., Kawamura G., Masuzaki S., Kobayashi M., Akiyama T., Peterson B. J., Mukai K., Sano R., Dai S. Y., Sakamoto R., Morisaki T., Ohno N.

NUCLEAR MATERIALS AND ENERGY 12 巻頁： 241 - 246 2017年8月

Molecular activated recombination in divertor simulation plasma on GAMMA 10/PDX 査読有り

Sakamoto M, Terakado A, Nojiri K, Ezumi N, Nakashima Y, Sawada K, Ichimura K, Fukumoto M, Oki K, Shimizu K, Ohno N, Masuzaki S, Togo S, Kohagura J, Yoshikawa M

NUCLEAR MATERIALS AND ENERGY 12 巻頁： 1004 - 1009 2017年8月

Fractality and growth of He bubbles in metals 査読有り

Shin Kajita, Atsushi M. Ito, Noriyasu Ohno

Physics Letters, Section A: General, Atomic and Solid State Physics 381 巻 ( 29 ) 頁： 2355 - 2362 2017年8月

Field emission from metal surfaces irradiated with helium plasmas 査読有り国際共著

Dogyun Hwangbo, Shin Kajita, Noriyasu Ohno, Dmitry Sinelnikov

IEEE Transactions on Plasma Science 45 巻 ( 8 ) 頁： 2080 - 2086 2017年8月

Effects of modified surfaces produced at plasma-facing surface on hydrogen release behavior in the LHD 査読有り

Nobuta Y, Masuzaki S, Tokitani M, Ashikawa N, Nagata D, Yoshida N, Oya Y, Yajima M, Motojima G, Kasahara H, Miyamoto M, Ohno N, Yamauchi Y

NUCLEAR MATERIALS AND ENERGY 12 巻頁： 483 - 487 2017年8月

Behavior of 23S metastable state He atoms in low-temperature recombining plasmas 査読有り

S.Kajita, T.Tsujihara, M.Aramaki, H.van der Meiden, H.Oshima, N.Ohno, H.Tanaka, R.Yasuhara, T.Akiyama, K.Fujii, T.Shikama

Physics of Plasmas 24 巻頁： 073301(8 pp) 2017年6月

Influence of expanding and contracting magnetic field configurations on detached plasma formation in a linear plasma device 査読有り

Y.Hayashi, N.Ohno, S.Kajita, H.Tanaka

Physics of Plasmas 24 巻頁： 062509(8 pp) 2017年6月

Recent progress of the JT-60SA project 査読有り国際共著国際誌

Shirai H., Barabaschi P., Kamada Y., Maksoud W.A., Aiba N., Akiyama T., Alonso J., Angioni C., Arai T., Arakawa H., Ardellier F., Artaud J.F., Asakura N., Ashikawa N., Barbato E., Barrera G., Baruzzo M., Baulaigue O., Beaufils S., Bécoulet M., Benkadda S., Benoit F., Bettini P., Beurskens M., Bierwage A., Boboc A., Boccaccini L., Bolzonella T., Bonne F., Borba D., Botija J., Bourdelle C., Brolatti G., Bruschi A., Bucalossi J., Cabrera-Pérez S., Canton A., Cardella A., Carvalho I., Challis C., Chapman I., Chiba S., Ciazynski D., Cismondi F., Clement-Lorenzo S., Coccoluto G., Cocilovo V., Coda S., Coelho R., Coletti A., Collin B., Conway G., Corato V., Costa P., Crisanti F., Cristofani C., Cruz N., Cucchiaro A., Dairaku M., Davis S., Day C., de Baar M., de la Luna E., De Tommasi G., De Vellis A., De Vries P., Decker J., Decool P., Delrez C., Di Pace L., Di Pietro E., Disset G., Donati A., Douai D., Dougnac H., Duchateau J.L., Duglue D., Dumas N., Dunai D., Ejiri A., Endo Y., Enoeda M., Falchetto G., Farina D., Farthing J., Fejoz P., Fernandez P., Ferro A., Fiamozzi-Zignani C., Fietz W., Figini L., Frello G., Frosi P., Fujita T., Fukuda T., Fukumoto M., Fukuyama A., Furukawa M., Furukawa M.

Nuclear Fusion 57 巻 ( 10 ) 2017年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Nuclear Fusion

The JT-60SA project has been implemented for the purpose of an early realization of fusion energy. With a powerful and versatile NBI and ECRF system, a flexible plasma-shaping capability, and various kinds of in-vessel coils to suppress MHD instabilities, JT-60SA plays an essential role in addressing the key physics and engineering issues of ITER and DEMO. It aims to achieve the long sustainment of high integrated performance plasmas under the high β N condition required in DEMO. The fabrication and installation of components and systems of JT-60SA procured by the EU and Japan are steadily progressing. The installation of toroidal field (TF) coils around the vacuum vessel started in December 2016. The commissioning of the cryogenic system and power supply system has been implemented in the Naka site, and JT-60SA will start operation in 2019. The JT-60SA research plan covers a wide area of issues in ITER and DEMO relevant operation regimes, and has been regularly updated on the basis of intensive discussion among European and Japanese researchers.

DOI： 10.1088/1741-4326/aa5d01

Scopus

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