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写真a

オンチ タクミ
恩地 拓己
ONCHI TAKUMI
所属
応用力学研究所 附属高温プラズマ理工学研究センター 助教
総合理工学府 総合理工学専攻(併任)
職名
助教
連絡先
メールアドレス
電話番号
0925837696
プロフィール
九州大学の球状トカマクQUESTにおいて実験研究を行っている. 主な研究テーマは「電子サイクロトロン加熱・電流駆動」. QUESTでは「プラズマ電流スタートアップ」や「同軸ヘリシティ入射」で共同研究を受け入れている. 複雑系が持つ順列エントロピーと統計的複雑性を調べる研究も実施中.
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学位

  • 学術博士

経歴

  • University of Saskatchewan

研究テーマ・研究キーワード

  • 研究テーマ:プラズマ時系列データの順列エントロピーと統計的複雑性

    研究キーワード:順列エントロピー,統計的複雑性,プラズマ実験,時系列データ

    研究期間: 2017年1月 - 2025年3月

  • 研究テーマ:パワーエレクトロニクスを使った核融合プラズマ生成加熱技術の開発

    研究キーワード:高電圧電源,パワーエレクトロニクス,トカマク

    研究期間: 2016年4月 - 2025年3月

  • 研究テーマ:球状トカマクQUESTにおける電子サイクロトロン加熱/電流駆動

    研究キーワード:プラズマ,球状トカマク,高周波加熱・電流駆動

    研究期間: 2015年4月 - 2025年3月

受賞

  • プラズマ・核融合学会第27回技術進歩賞

    2022年9月   プラズマ・核融合学会   先進核融合装置プラズマ加熱用低周波数ジャイロトロンの開発研究

論文

  • Non-inductive plasma current ramp-up through oblique injection of harmonic electron cyclotron waves on the QUEST spherical tokamak 査読 国際誌

    Onchi, T.; Idei, H.; Fukuyama, M.; Ogata, D.; Ashida, R.; Kariya, T.; Ejiri, A.; Matsuzaki, K.; Osawa, Y.; Peng, Y.; Kojima, S.; Watanabe, O.; Hasegawa, M.; Nakamura, K.; Kuroda, K.; Ikezoe, R.; Ido, T.; Hanada, K.; Bertelli, N.; Ono, M.; Fukuyama, A.

    PHYSICS OF PLASMAS   28 ( 2 )   022505   2021年2月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1063/5.0031357

  • Permutation entropy and statistical complexity in characterising low-aspect-ratio reversed-field pinch plasma 査読 国際誌

    T. Onchi, A. Fujisawa, A. Sanpei, H. Himura, S. Masamune, and RELAX team

    Physica Scripta   92 ( 5 )   055601   2017年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: https://doi.org/10.1088/1402-4896/aa6689

  • Development Toward a Repetitive Compact Torus Injector 査読 国際誌

    Takumi Onchi, D. McColl, A. Rohollahi, C. Xiao, A. Hirose, M. Dreval, S. Wolfe

    IEEE Transactions on Plasma Science   44 ( 2 )   2016年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Effects of compact torus injection on toroidal flow in the STOR-M tokamak 査読 国際誌

    T. Onchi, Y. Liu, M. Dreval, D. McColl, S. Elgriw, D. Liu, T. Asai, C. Xiao, A. Hirose

    Plasma Physics and Controlled Fusion   55 ( 3 )   2013年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Tangential soft-x ray imaging for three-dimensional structural studies in a reversed field pinch 査読 国際誌

    T. Onchi, R. Ikezoe, K. Oki, A. Sanpei, H. Himura, S. Masamune

    Review of Scientific Instruments   81 ( 7 )   2010年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Heating characteristic of electron Bernstein wave using high-field side X-mode injection in QUEST

    Murakami, T; Kojima, S; Hanada, K; Idei, H; Ido, T; Ikezoe, R; Hasegawa, M; Onchi, T; Kono, K; Kuroda, K; Ejiri, A

    PLASMA PHYSICS AND CONTROLLED FUSION   66 ( 11 )   2024年11月   ISSN:0741-3335 eISSN:1361-6587

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    出版者・発行元:Plasma Physics and Controlled Fusion  

    A comparative investigation was conducted to assess the impact of high-field side (HFS) extraordinary (X) mode (HFS X) injection and low-field side (LFS) ordinary (O) mode (LFS O) injection of 8.2 GHz radio frequency (RF) power in the Q-shu University experimental steady-state spherical tokamak. In the case of the HFS X injection, the ratio of electron plasma frequency and RF frequency f pe / f RF was 1.3, indicating an overdense plasma, whereas in the LFS O injection, this ratio was 0.9. Distinctive features emerged in the electron temperature and density profiles between the two injection scenarios. In the HFS X injection, the profiles peaked between the fundamental electron cyclotron resonance (ECR) layer and the upper hybrid resonance layer. Conversely, in the LFS O injection, the peaks were situated near the 1st ECR layer. This implies effective excitation of the electron Bernstein wave (EBW) in the case of the HFS X injection, with the wave power being absorbed through the doppler-shifted ECR of the EBW. Density and temperature oscillations were observed only in the start-up phase of the HFS X injection, which may correlate with the presence of the left-hand cutoff of the X-mode. These findings will be contributed to understand the distinctive characteristics associated with plasma heating through EBW excitation in the HFS X injection.

    DOI: 10.1088/1361-6587/ad802e

    Web of Science

    Scopus

  • Electron cyclotron current start-up using a retarding electric field in the QUEST spherical tokamak

    Onchi, T; Idei, H; Hanada, K; Watanabe, O; Miyata, R; Zhang, Y; Koide, Y; Otsuka, Y; Yamaguchi, T; Higashijima, A; Nagata, T; Sekiya, I; Shimabukuro, S; Niiya, I; Kono, K; Zennifa, F; Nakamura, K; Ikezoe, R; Hasegawa, M; Kuroda, K; Nagashima, Y; Ido, T; Kariya, T; Ejiri, A; Murakami, S; Fukuyama, A; Kosuga, Y

    NUCLEAR FUSION   64 ( 10 )   2024年10月   ISSN:0029-5515 eISSN:1741-4326

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    出版者・発行元:Nuclear Fusion  

    The plasma current start-up experiment is conducted through electron cyclotron (EC) heating in the QUEST spherical tokamak. During the EC heating, the application of a toroidal electric field in the opposite direction to the plasma current effectively inhibits the growth of energetic electrons. Observations show rapid increases in plasma current and hard x-ray count immediately following the cancellation of the retarding electric field. When a compact tokamak configuration maintains equilibrium on the high field side, along with the retarding field, it leads to effective bulk electron heating. This heating achieved an electron temperature of Te ≈ 1 keV at electron density ne > 1.0 × 1018 m−3. Ray tracing of the EC wave verifies that more power absorption into plasma through a single-pass occurs around the second resonance layer with higher values of electron density and temperature.

    DOI: 10.1088/1741-4326/ad6914

    Web of Science

    Scopus

  • Hydrogen removal by electron cyclotron wall conditioning with neon gas and its impact of tokamak plasma start-up on the QUEST spherical tokamak

    Fukumoto, M; Yue, QL; Hanada, K; Kojima, S; Nakano, T; Yoshida, N; Ikezoe, R; Nagashima, Y; Ido, T; Onchi, T; Idei, H; Iguchi, H; Komiyama, T; Shikama, T; Ejiri, A; Masuzaki, S; Sakamoto, M; Ueda, Y; Kuroda, K; Kono, K; Shimabukuro, S; Higashijima, A

    NUCLEAR FUSION   64 ( 6 )   2024年6月   ISSN:0029-5515 eISSN:1741-4326

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    出版者・発行元:Nuclear Fusion  

    Electron cyclotron wall conditioning with neon gas (Ne-ECWC) has been performed on the normal conducting spherial tokamak QUEST with metal walls under a trapped particle configuration with O-mode EC waves including X-mode polarization with a frequency of 8.2 GHz and an injection power of 16 kW. The Ne-ECWC removes hydrogen from the wall with small neon retention. The Ne-ECWC decreases hydrogen recycling at the following tokamak discharges, contributing to an improvement of the following tokamak plasma start-up: the plasma current increases and the start-up timing of the plasma current shifts forward. However, defects such as voids and bubbles are formed on tungsten surface exposed to the Ne-ECWC plasma.

    DOI: 10.1088/1741-4326/ad3d6e

    Web of Science

    Scopus

  • Improving Current Distribution Model for EBWCD using Flux Loops in QUEST

    花田 和明, 黒田 賢剛, 恩地 拓己, 出射 浩, 池添 竜也, 長谷川 真, 永島 芳彦, 井戸 毅, 木下 稔基

    Evergreen   11 ( 2 )   555 - 562   2024年6月   ISSN:21890420 eISSN:24325953

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    記述言語:英語   出版者・発行元:九州大学グリーンテクノロジー研究教育センター  

    During the early phase of tokamak plasma start-up prior to the formation of a closed magnetic surface, various plasma current profiles are expected to be observed. Especially, the noninductive current drive (CD) by the electron Bernstein wave (EBW) is likely to be the most dominant, and the current profile is expected to focus on a local area predicted by the theoretical model. In addition, the EBWCD direction could be affected by a horizontal magnetic field induced by a toroidal magnetic field coil and feed-through. The magnetic flux data cannot be fitted by using a previous model described by Yoshinaga23), and hence, this model needs improvement. Consequently, an improved model is introduced in this paper based on the theoretical prediction of EBWCD. This model can be applied to reproduce the complex plasma current profile accurately during the early phase of the tokamak plasma start-up.

    DOI: 10.5109/7183306

    Scopus

    CiNii Research

  • Hydrogen removal by electron cyclotron wall conditioning with neon gas and its impact of tokamak plasma start-up on the QUEST spherical tokamak 査読 国際誌

    Masakatsu Fukumoto, Qilin Yue, Kazuaki Hanada, Shinichiro Kojima, Tomohide Nakano, NY Yoshida, Ryuya Ikezoe, Yoshihiko Nagashima, Takeshi Ido, Takumi Onchi, Hiroshi Idei, Hiroki Iguchi, Takumi Komiyama, Taiichi Shikama, Akira Ejiri, Suguru Masuzaki, Mizuki Sakamoto, Yoshio Ueda, Kengoh Kuroda, Kaori Kono, Shun Shimabukuro, Aki Higashijima

    Nuclear Fusion   64 ( 6 )   066022   2024年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Comparison of electron temperature and density measured by helium line intensity ratio and Thomson scattering methods in ECH spherical tokamak plasma

    Komiyama, T; Shikama, T; Hanada, K; Ido, T; Onchi, T; Kono, K; Ejiri, A; Hasegawa, M; Inoue, S; Hasuo, M; Idei, H; Yue, QL; Kuroda, K; Higashijima, A; Prapan, P

    PLASMA PHYSICS AND CONTROLLED FUSION   66 ( 4 )   2024年4月   ISSN:0741-3335 eISSN:1361-6587

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    出版者・発行元:Plasma Physics and Controlled Fusion  

    The electron temperature and density profiles in the midplane of a spherical tokamak plasma produced by electron cyclotron heating (ECH) in Q-shu University experiment with steady-state spherical tokamak (QUEST) are measured by the helium line intensity ratio method. The measured profiles are compared with those obtained by the Thomson scattering method, and the measured temperatures and densities are found to agree within factors of ∼2 and ∼6, respectively. Taken together with the previous results of comparisons performed in the scrape-off layers of several toroidal devices, the same degree of agreement between the helium line intensity ratio method and other methods is obtained in the ranges of 7-100 eV for temperature and 4 × 1016-1 × 1019 m−3 for density.

    DOI: 10.1088/1361-6587/ad2c2a

    Web of Science

    Scopus

  • Comparison of electron temperature and density measured by helium line intensity ratio and Thomson scattering methods in ECH spherical tokamak plasma Authors 査読 国際誌

    Takumi Komiyama, Taiichi Shikama, Kazuaki Hanada, Takeshi Ido, Takumi Onchi, Kaori Kono, Akira Ejiri, Makoto Hasegawa, Satoshi Inoue, Masahiro Hasuo, Hiroshi Idei, Qilin Yue, Kengoh Kuroda, Aki Higashijima, Pakkapawn Prapan

    Plasma Physics and Controlled Fusion   66   045018   2024年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Demonstration of transient CHI startup using a floating biased electrode configuration

    Kuroda, K; Raman, R; Onchi, T; Hasegawa, M; Hanada, K; Ono, M; Nelson, BA; Rogers, J; Ikezoe, R; Idei, H; Ido, T; Nagata, M; Mitarai, O; Nishino, N; Otsuka, Y; Zhang, Y; Kono, K; Kawasaki, S; Nagata, T; Higashijima, A; Shimabukuro, S; Niiya, I; Sekiya, I; Nakamura, K; Takase, Y; Ejiri, A; Murakami, S

    NUCLEAR FUSION   64 ( 1 )   2024年1月   ISSN:0029-5515 eISSN:1741-4326

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    出版者・発行元:Nuclear Fusion  

    Results from the successful solenoid-free plasma startup using the method of transient coaxial helicity injection (transient CHI) in the QUEST spherical tokamak (ST) are reported. Unlike previous applications of CHI on HIT-II and on NSTX which required two toroidal insulating breaks to the vacuum vessel, QUEST uses a first of its kind, floating single biased electrode configuration, which does not use such a vacuum break. Instead, the CHI electrode is simply insulated from the outer lower divertor plate support structure. This configuration is much more suitable for implementation in a fusion reactor than the previous configurations. Transient CHI generated toroidal currents of 135 kA were obtained. The toroidal current during the formation of a closed flux configuration was over 50 kA. These results bode well for the application of transient CHI in a new generation of compact high-field STs and tokamaks in which the space for the central solenoid is very restricted.

    DOI: 10.1088/1741-4326/ad0dd6

    Web of Science

    Scopus

  • Demonstration of transient CHI startup using a floating biased electrode configuration 査読 国際誌

    Kengoh Kuroda, R Raman, T Onchi, M Hasegawa, K Hanada, M Ono, BA Nelson, J Rogers, R Ikezoe, H Idei, T Ido, M Nagata, O Mitarai, N Nishino, Y Otsuka, Y Zhang, K Kono, S Kawasaki, T Nagata, A Higashijima, S Shimabukuro, I Niiya, I Sekiya, K Nakamura, Y Takase, A Ejiri, S Murakami

    Nuclear Fusion   64 ( 1 )   014002   2023年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Effects of toroidally-distributed-divertor biasing on scrape-off-layer (SOL) current drive, divertor particle flux and fast electron confinement in the QUEST spherical tokamak

    Toi, K; Onchi, T; Zushi, H; Kuroda, K; Idei, H; Hanada, K; Hasegawa, M; Kojima, S; Ikezoe, R; Ido, T; Kawasaki, S; Higashijima, A

    NUCLEAR FUSION   63 ( 10 )   2023年10月   ISSN:0029-5515 eISSN:1741-4326

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    出版者・発行元:Nuclear Fusion  

    A novel divertor biasing by four biasing plates distributed toroidally (TDDB) on the upper divertor target plate is applied to low density tokamak plasmas started-up by 28 GHz 2nd harmonic electron cyclotron current drive (ECCD) in a quasi-double null configuration of the QUEST spherical tokamak (ST). In the ST plasmas of line averaged electron density < n e > ∼0.7-1 × 1018 m−3, about 20%-40% of the current I bias driven by ∼85 V sawtooth bias voltage reaches the lower divertor plate along the biased scrape-off-layer (SOL) flux tube as the SOL current I SOL . The fact I SOL is noticeably lower than I bias indicates an appreciable leakage of parallel current from the biased SOL flux tube. The leakage currents in the toroidal and radial directions are confirmed by detection of them using the unbiased plates in the TDDB experiments. From the ion saturation current density profile obtained by a divertor Langmuir probe array, the fall-off lengths of divertor particle flux are estimated together with the strike line position. Total particle flux to the upper divertor, evaluated by the integrated ion saturation current density profile is reduced by up to 45% during positive biasing of the TDDB, depending on the position of the strike line to the biased plate. In addition, the TDDB also induces a noticeable loss of fast electrons produced by ECCD, leading to an ∼2% reduction in the maximum toroidal current of the ST plasma compared to a shot without the TDDB. Reduction of the divertor particle flux and enhancement of the fast electron losses are thought to be dominantly caused by E × B drift induced by the TDDB. In the present experimental conditions, the effects of magnetic perturbations produced by the SOL currents on the fast electron losses can be neglected because of a too small SOL current.

    DOI: 10.1088/1741-4326/acee13

    Web of Science

    Scopus

  • Spectroscopic measurement of increases in hydrogen molecular rotational temperature with plasma-facing surface temperature and due to collisional-radiative processes in tokamaks

    Yoneda, N; Shikama, T; Scotti, F; Hanada, K; Iguchi, H; Idei, H; Onchi, T; Ejiri, A; Ido, T; Kono, K; Peng, Y; Osawa, Y; Yatomi, G; Kidani, A; Kudo, M; Hiraka, R; Takeda, K; Bell, RE; Maan, A; Boyle, DP; Majeski, R; Soukhanovskii, VA; Groth, M; McLean, AG; Wilcox, RS; Lasnier, C; Nakamura, K; Nagashima, Y; Ikezoe, R; Hasegawa, M; Kuroda, K; Higashijima, A; Nagata, T; Shimabukuro, S; Niiya, I; Sekiya, I; Hasuo, M

    NUCLEAR FUSION   63 ( 9 )   2023年9月   ISSN:0029-5515 eISSN:1741-4326

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    出版者・発行元:Nuclear Fusion  

    Spatially resolved rotational temperature of ground state hydrogen molecules desorbed from plasma-facing surface was measured in QUEST, LTX-β, and DIII-D tokamaks, and the increases of the rotational temperature with the surface temperature and due to collisional-radiative processes in the plasmas were evaluated. The increase due to collisional-radiative processes was calculated by solving rate equations considering electron and proton collisional excitation and deexcitation and spontaneous emission. The calculation results suggest a high sensitivity for the rotational temperature to electron and proton densities, but a negligible sensitivity to the electron, proton, and surface temperatures. In the three tokamaks with different plasma parameters and plasma-facing surface materials, the spatial profile of the rotational temperature was estimated using Fulcher-α emission lines (600-608 nm). In QUEST, the spatial profile of the rotational temperature was estimated from spatially resolved spectra. In the other tokamaks, the rotational temperature was evaluated assuming a single point emission with a location determined from the Fulcher-α emission profile as measured with a filtered camera. In metal-walled devices QUEST and LTX-β, the rotational temperature increased with the surface temperature, and the calculated collisional-radiative increase is consistent with measured increase assuming that the rotational temperature at the surface is approximately 500-600 K higher than the surface temperature. In DIII-D with carbon walls, a larger collisional-radiative increase than the other tokamaks was observed because of the higher density leading to a large difference from the calculated increase compared to the other smaller tokamaks. Measurement of the Fulcher-α emission profile with higher spatial resolution in DIII-D may reduce the difference and reveal the effect of the surface temperature on the rotational temperature. These results show the increases in the rotational temperature with the surface temperature and due to the collisional-radiative processes.

    DOI: 10.1088/1741-4326/acd4d1

    Web of Science

    Scopus

  • Spectroscopic measurement of increases in hydrogen molecular rotational temperature with plasma-facing surface temperature and due to collisional-radiative processes in tokamaks

    Yoneda N., Shikama T., Scotti F., Hanada K., Iguchi H., Idei H., Onchi T., Ejiri A., Ido T., Kono K., Peng Y., Osawa Y., Yatomi G., Kidani A., Kudo M., Hiraka R., Takeda K., Bell R.E., Maan A., Boyle D.P., Majeski R., Soukhanovskii V.A., Groth M., McLean A.G., Wilcox R.S., Lasnier C., Nakamura K., Nagashima Y., Ikezoe R., Hasegawa M., Kuroda K., Higashijima A., Nagata T., Shimabukuro S., Niiya I., Sekiya I., Hasuo M.

    Nuclear Fusion   63 ( 9 )   2023年9月   ISSN:00295515 eISSN:17414326

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    記述言語:英語  

    Spatially resolved rotational temperature of ground state hydrogen molecules desorbed from plasma-facing surface was measured in QUEST, LTX-β, and DIII-D tokamaks, and the increases of the rotational temperature with the surface temperature and due to collisional-radiative processes in the plasmas were evaluated. The increase due to collisional-radiative processes was calculated by solving rate equations considering electron and proton collisional excitation and deexcitation and spontaneous emission. The calculation results suggest a high sensitivity for the rotational temperature to electron and proton densities, but a negligible sensitivity to the electron, proton, and surface temperatures. In the three tokamaks with different plasma parameters and plasma-facing surface materials, the spatial profile of the rotational temperature was estimated using Fulcher-α emission lines (600–608 nm). In QUEST, the spatial profile of the rotational temperature was estimated from spatially resolved spectra. In the other tokamaks, the rotational temperature was evaluated assuming a single point emission with a location determined from the Fulcher-α emission profile as measured with a filtered camera. In metal-walled devices QUEST and LTX-β, the rotational temperature increased with the surface temperature, and the calculated collisional-radiative increase is consistent with measured increase assuming that the rotational temperature at the surface is approximately 500–600 K higher than the surface temperature. In DIII-D with carbon walls, a larger collisional-radiative increase than the other tokamaks was observed because of the higher density leading to a large difference from the calculated increase compared to the other smaller tokamaks. Measurement of the Fulcher-α emission profile with higher spatial resolution in DIII-D may reduce the difference and reveal the effect of the surface temperature on the rotational temperature. These results show the increases in the rotational temperature with the surface temperature and due to the collisional-radiative processes.

    CiNii Research

  • Effects of toroidally-distributed-divertor biasing on scrape-off-layer (SOL) current drive, divertor particle flux and fast electron confinement in the QUEST spherical tokamak 査読 国際誌

    Kazuo Toi, Takumi Onchi, Hideki Zushi, Kengoh Kuroda, Hiroshi Idei, Kazuaki Hanada, Makoto Hasegawa, Shinichiro Kojima, Ryuya Ikezoe, Takeshi Ido, Shoji Kawasaki, Aki Higashijima, QUEST Experiment Group

    Nuclear Fusion   63 ( 10 )   106018   2023年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Sudden Change Events of Plasma Current during Electron-Cyclotron Current Start-Up on the QUEST Spherical Tokamak

    Ikezoe, R; Takeda, K; Kuroda, K; Onchi, T; Nagata, T; Sekiya, I; Idei, H; Zennifa, F; Zhang, YF; Sakai, S; Miyata, R; Yamaguchi, T; Hasegawa, M; Nagashima, Y; Ido, T; Hanada, K

    PLASMA AND FUSION RESEARCH   18 ( 0 )   2402066 - 2402066   2023年8月   ISSN:1880-6821 eISSN:18806821

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    記述言語:英語   出版者・発行元:一般社団法人 プラズマ・核融合学会  

    Non-inductive plasma current start-up experiments have been conducted using 2nd harmonic electroncyclotron resonance heating (ECRH) on the QUEST spherical tokamak. Sudden or abrupt changes in plasma current, referred to as sudden change events (SCEs), have been frequently observed during these experiments. To investigate these events, fast magnetic activity was measured globally by installing arrays of magnetic pick-up coils inside the vacuum vessel on QUEST. Analysis revealed that all observed SCEs could be classified into three categories based on their magnetic characteristics. In one type of event, called SCE–III, the plasma current suddenly decreases by up to 50% instantaneously, occurring in a wide discharge region achieved using 2nd ECRH start-up on QUEST. These SCE–III events may potentially lead to disruptions in future discharges at higher powers.

    DOI: 10.1585/pfr.18.2402066

    Web of Science

    Scopus

    CiNii Research

  • Sudden Change Events of Plasma Current during Electron-Cyclotron Current Start-Up on the QUEST Spherical Tokamak 査読 国際誌

    Ryuya Ikezoe, Kosuke Takeda, Kengoh Kuroda, Takumi Onchi, Takahiro Nagata, Izumi Sekiya, Hiroshi Idei, Fadilla Zennifa, Yifan Zhang, Seiya Sakai, Rikuya Miyata, Takahiro Yamaguchi, Makoto Hasegawa, Yoshihiko Nagashima, Takeshi Ido, Kazuaki Hanada

    Plasma and Fusion Research   18   2402066 - 2402066   2023年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Spectroscopic measurement of increases in hydrogen molecular rotational temperature with plasma-facing surface temperature and due to collisional-radiative processes in tokamaks 招待 査読 国際誌

    N Yoneda, T Shikama, F Scotti, K Hanada, H Iguchi, H Idei, T Onchi, A Ejiri, T Ido, K Kono, Y Peng, Y Osawa, G Yatomi, A Kidani, M Kudo, R Hiraka, K Takeda, RE Bell, A Maan, DP Boyle, R Majeski, VA Soukhanovskii, M Groth, AG McLean, RS Wilcox, C Lasnier, Kazuo Nakamura, Y Nagashima, R Ikezoe, M Hasegawa, Kengoh Kuroda, A Higashijima, T Nagata, S Shimabukuro, I Niiya, I Sekiya, M Hasuo

    Nuclear Fusion   2023年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Circuit design for doubling the toroidal magnetic field on the QUEST spherical tokamak

    Onchi, T; Idei, H; Yanagi, N; Zhang, YF; Nakamura, K; Kuroda, K; Hasegawa, M; Ikezoe, R; Hanada, K; Ido, T; Kobayashi, M; Ogawa, Y; Yoshitani, M; Kawamura, T

    FUSION ENGINEERING AND DESIGN   192   2023年7月   ISSN:0920-3796 eISSN:1873-7196

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    出版者・発行元:Fusion Engineering and Design  

    Various scenarios of electron cyclotron heating can be explored in a spherical tokamak with a high toroidal field. On the QUEST spherical tokamak, doubling the toroidal field results in the emergence of the fundamental resonance layer for 28 GHz electron cyclotron waves. The second-harmonic resonance layer shifts toward the plasma central area. To increase the coil current from 50 to 100 kA, a current source is designed with 125 modules in parallel. The module power supply comprises a bank of lithium-ion capacitors and a DC–DC buck converter. In the bench test of a single module, the current was found to increase linearly and maintained the flat-top as programmed.

    DOI: 10.1016/j.fusengdes.2023.113794

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  • QUEST Database for Tokamak Big Data

    Hasegawa, M; Higashijima, A; Niiya, I; Hanada, K; Idei, H; Ido, T; Ikezoe, R; Onchi, T; Kuroda, K; Sakurai, D

    PLASMA AND FUSION RESEARCH   18 ( 0 )   1305048 - 1305048   2023年6月   ISSN:1880-6821 eISSN:18806821

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    記述言語:英語   出版者・発行元:一般社団法人 プラズマ・核融合学会  

    A database has been developed to provide a highly efficient data analysis environment by registering various types of data obtained in the QUEST (Q-shu University Experiment with Steady-State Spherical Tokamak) experiments and providing the data to researchers through standard SQL query output. In conventional experiments, measurements are usually obtained using several instruments, and the results are often stored separately in proprietary formats. An analysis to collect distributed files and convert them into appropriate formats individually was necessary, which led to a decrease in analysis efficiency. In order to build a system to centrally store and provide data, we constructed new servers, each for registering data in a database and for extracting data from the database and visualizing the data. As a result, various real-time monitoring data can be registered in the database, and data retrieval for analysis can be performed easily with a unified user interface. The construction of this database has made it possible to easily retrieve real-time monitoring data and a wide variety of table data, enabling analysis from a new perspective, and improving analysis efficiency.

    DOI: 10.1585/pfr.18.1305048

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  • QUEST Database for Tokamak Big Data 査読 国際誌

    Makoto HASEGAWA, Aki HIGASHIJIMA, Ichiro NIIYA, Kazuaki HANADA, Hiroshi IDEI, Takeshi IDO, Ryuya IKEZOE, Takumi ONCHI, Kengo KURODA, Daisuke SAKURAI

    Plasma and Fusion Research   18   1305048   2023年6月

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  • A versatile power supply system for the central solenoid of the QUEST spherical tokamak 査読 国際誌

    Yifan Zhang, Takumi Onchi, Kazuo Nakamura, Yuya Otsuka, Yuji Koide, Qilin Yue, Takahiro Nagata, Shoji Kawasaki, Kengoh Kuroda, Makoto Hasegawa, Ryuya Ikezoe, Takeshi Ido, Kazuaki Hanada, Hiroshi Idei

    Fusion Engineering and Design   191   113648   2023年6月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

  • QUEST Database for Tokamak Big Data 査読 国際誌

    Makoto HASEGAWA, Aki HIGASHIJIMA, Ichiro NIIYA, Kazuaki HANADA, Hiroshi IDEI, Takeshi IDO, Ryuya IKEZOE, Takumi ONCHI, Kengo KURODA, Daisuke SAKURAI

    Plasma and Fusion Research   18   1305048   2023年6月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

  • Circuit design for doubling the toroidal magnetic field on the QUEST spherical tokamak 招待 査読 国際誌

    Takumi Onchi, Hiroshi Idei, Nagato Yanagi, Yifan Zhang, Kazuo Nakamura, Kengoh Kuroda, Makoto Hasegawa, Ryuya Ikezoe, Kazuaki Hanada, Takeshi Ido, Masahiro Kobayashi, Yuichi Ogawa, Minoru Yoshitani, Takemi Kawamura

    Circuit design for doubling the toroidal magnetic field on the QUEST spherical tokamak   192   113794   2023年6月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

  • Circuit design for doubling the toroidal magnetic field on the QUEST spherical tokamak 招待 査読 国際誌

    Takumi Onchi, Hiroshi Idei, Nagato Yanagi, Yifan Zhang, Kazuo Nakamura, Kengoh Kuroda, Makoto Hasegawa, Ryuya Ikezoe, Kazuaki Hanada, Takeshi Ido, Masahiro Kobayashi, Yuichi Ogawa, Minoru Yoshitani, Takemi Kawamura

    Circuit design for doubling the toroidal magnetic field on the QUEST spherical tokamak   192   113794   2023年6月

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  • A versatile power supply system for the central solenoid of the QUEST spherical tokamak 査読 国際誌

    Yifan Zhang, Takumi Onchi, Kazuo Nakamura, Yuya Otsuka, Yuji Koide, Qilin Yue, Takahiro Nagata, Shoji Kawasaki, Kengoh Kuroda, Makoto Hasegawa, Ryuya Ikezoe, Takeshi Ido, Kazuaki Hanada, Hiroshi Idei

    Fusion Engineering and Design   191   113648   2023年6月

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  • A versatile power supply system for the central solenoid of the QUEST spherical tokamak

    Zhang, YF; Onchi, T; Nakamura, K; Otsuka, Y; Koide, Y; Yue, QL; Nagata, T; Kawasaki, S; Kuroda, K; Hasegawa, M; Ikezoe, R; Ido, T; Hanada, K; Idei, H

    FUSION ENGINEERING AND DESIGN   191   2023年6月   ISSN:0920-3796 eISSN:1873-7196

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    出版者・発行元:Fusion Engineering and Design  

    Here, a versatile power supply system, consisting of two current sources, insulated-gate bipolar transistor stacks, and a capacitor bank, is proposed for application in various operations of the QUEST spherical tokamak. The central solenoid coil in this system can carrying a maximum current and voltage of ±8 kA and ±375 V, respectively. In plasma start-up experiments based on ohmic heating through double flux swing, a plasma current of over 100 kA is stably obtained. Moreover, the feedback control of the thyristor power supply is utilized to control the plasma current, plasma shape, and position. The oscillating central-solenoid current applies a bipolar loop voltage at constant time intervals, and the capacitor bank discharge facilitates a co-axial helicity injection as well as amplifies the toroidal current.

    DOI: 10.1016/j.fusengdes.2023.113648

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  • Quaternion Analysis of Transient Phenomena of Motor-Generator

    Nakamura, K; Zhang, YF; Onchi, T; Idei, H; Hasegawa, M; Tokunaga, K; Hanada, K; Ido, T; Ikezoe, R; Chikaraishi, H; Mitarai, O; Kawasaki, S; Higashijima, A; Nagata, T; Shimabukuro, S

    PLASMA AND FUSION RESEARCH   18 ( 0 )   2405035 - 2405035   2023年5月   ISSN:18806821 eISSN:18806821

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    記述言語:英語   出版者・発行元:一般社団法人 プラズマ・核融合学会  

    A motor-generator slowly converts low electrical power to the large rotating energy of the induction motor, which is then converted to the higher electrical power of the synchronous generator through a pulse. Such a cycle is repeated in a tokamak plasma experiment. In the transient phase at the start of the synchronous generator, high transient voltage appears in the armature windings repeatedly. Due to the repeatability, it is imperative to estimate the high voltage and control it so that the maximum voltage is kept under a tolerable value. A quaternion is a four-dimensional hypercomplex number that is good at describing three-dimensional rotation. Utilizing the quaternion capability, a three-phase motor-generator is analyzed using three-dimensional rotation. The mechanical rotation was anlyzed by the rotation quaternion. The salient pole-type rotating field can be manipulated by direct-quadrature conversion even in quaternion analysis. The rotating dynamics and electrical phenomena of a motor-generator can be analyzed by considering the quaternion power from the motor-generator and the electrical load for plasma control.

    DOI: 10.1585/pfr.18.2405035

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  • Initial testing of ohmic heating through double flux swing during electron cyclotron start-up in the QUEST spherical tokamak 招待 査読 国際誌

    Zhang, YF; Onchi, T; Nakamura, K; Yue, QL; Nagata, T; Kawasaki, S; Kuroda, K; Hasegawa, M; Ikezoe, R; Ido, T; Hanada, K; Idei, H

    PLASMA SCIENCE & TECHNOLOGY   25 ( 5 )   2023年5月   ISSN:1009-0630 eISSN:2058-6272

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    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:Plasma Science and Technology  

    A power-supply system was developed for Ohmic heating (OH) to double × 1018 the amount of change magnetic flux in the primary central solenoid (CS) on the QUEST spherical tokamak. Two power supplies are connected with stacks of insulated-gate bipolar transistors, and sequentially operated to generate positive and negative CS currents. This bipolar power-supply system is controlled via a field-programmable gate array, which guarantees the safety of the entire system operation. The new OH system, assisted by electron cyclotron heating, enables the stable generation of plasma currents exceeding 100 kA. Moreover, the achieved electron density over the wide range in the major radial direction exceeds the cut-off density for one of the high-power microwave sources in QUEST. This strategy yields target plasmas for future experiments with the electron Bernstein wave.

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  • Quaternion Analysis of Transient Phenomena of Motor-Generator 招待 査読 国際誌

    Kazuo Nakamura, Yifan Zhang, Takumi Onchi, Hiroshi Idei, Makoto Hasegawa, Kazutoshi Tokunaga, Kazuaki Hanada, Takeshi Ido, Ryuya Ikezoe, Hirotaka Chikaraishi, Osamu Mitarai, Shoji Kawasaki, Aki Higashijima, Takahiro Nagata, Shun Shimabukuro

    Plasma and Fusion Research   Volume 18(2023)2405035   2023年4月

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  • 8.56-GHz quasi-optical launcher system with incident-mode selectivity on the QUEST spherical tokamak 招待 査読 国際誌

    Idei, H; Sakaguchi, M; Mishra, K; Onchi, T; Ikezoe, R; Watanabe, O; Tanaka, Y; Saito, T; Ido, T; Hanada, K

    FUSION ENGINEERING AND DESIGN   189   2023年4月   ISSN:0920-3796 eISSN:1873-7196

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    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:Fusion Engineering and Design  

    An 8.56-GHz quasi-optical launcher system with incident-mode selectivity was developed for non-inductive electron cyclotron (EC) plasma ramp-up and long-pulse sustainment, and effective bulk-electron heating on the Q-shu University experiment with steady-state spherical tokamak (QUEST). A novel polarization-selective system was proposed to conduct fundamental and second harmonic EC heating and current drive experiments with ordinary and extra-ordinary mode waves, respectively. Selectivity of the incident modes or polarizations was confirmed using the whole developed system at a low power level. A large-sized mirror launcher was developed to inject the beam whose size was as small as possible near the QUEST major radius. The designed mirror performance was checked using a three-dimensional electromagnetic-wave simulator and a low-power test. Ultimately, 0.15-m sized beams for both the two polarizations were successfully attained near the QUEST major radius, even in low-frequency applications with long propagation.

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  • Quaternion Analysis of Transient Phenomena of Motor-Generator 招待 査読 国際誌

    Kazuo Nakamura, Yifan Zhang, Takumi Onchi, Hiroshi Idei, Makoto Hasegawa, Kazutoshi Tokunaga, Kazuaki Hanada, Takeshi Ido, Ryuya Ikezoe, Hirotaka Chikaraishi, Osamu Mitarai, Shoji Kawasaki, Aki Higashijima, Takahiro Nagata, Shun Shimabukuro

    Plasma and Fusion Research   Volume 18(2023)2405035   2023年4月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

  • Development of Thomson Scattering Measurement System for Long Duration Discharges on the QUEST Spherical Tokamak 招待 査読 国際誌

    Kono, K; Ido, T; Ejiri, A; Hanada, K; Yue, QL; Hasegawa, M; Peng, Y; Sakai, S; Ikezoe, R; Idei, H; Kawasaki, S; Kuroda, K; Onchi, T; Nagashima, Y; Jang, S

    PLASMA AND FUSION RESEARCH   18 ( 0 )   1405012-1 - 1405012-4   2023年2月   ISSN:1880-6821 eISSN:18806821

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    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:一般社団法人 プラズマ・核融合学会  

    The Thomson scattering control system has been modified to measure the time evolution of the electron density and temperature profiles during long duration discharges in the QUEST spherical tokamak. The system consists of a signal generator and a control circuit. The former accepts a QUEST main trigger and provides multiple triggers, each of which starts a short-term (e.g. 15 s) measurement. The latter provides triggers to synchronize the oscilloscope and laser oscillation during a short-term measurement. The system was used in 1000 s long duration discharges in QUEST, and the temporal evolutions of density and temperature profiles were obtained successfully. It was found the profiles are stationary after about 300 s.

    DOI: 10.1585/pfr.18.1405012

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  • Improvements to the High-Field-Side Transient CHI System on QUEST 招待 査読 国際誌

    Kuroda, K; Raman, R; Hasegawa, M; Onchi, T; Hanada, K; Ono, M; Nelson, BA; Rogers, J; Ikezoe, R; Idei, H; Ido, T; Mitarai, O; Nagata, M; Kawasaki, S; Nagata, T; Higashijima, A; Shimabukuro, S; Niiya, I; Sekiya, I; Kojima, S; Nakamura, K; Takase, Y; Murakami, S

    JOURNAL OF FUSION ENERGY   41 ( 2 )   2022年12月   ISSN:0164-0313 eISSN:1572-9591

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    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:Journal of Fusion Energy  

    Transient coaxial helicity injection (CHI) is a promising candidate for solenoid-free plasma current start-up in a low-aspect-ratio tokamak in support of developing fully non-inductive scenarios. The aim of the transient CHI research on QUEST is to develop a reactor-relevant CHI design. On QUEST, a CHI discharge is initiated by driving current along magnetic field lines that connect an electrically insulated electrode plate (which is referred to as a bias electrode) to a vessel component at the bottom region of the spherical tokamak. In the first application of CHI on QUEST, the electrically insulated electrode plate was biased with respect to the outer vessel in a configuration referred to as low-field-side (LFS) injection. To maintain a narrow injector flux footprint width throughout the discharge, QUEST is now developing a high-field-side (HFS) injection configuration, in which the electrically insulated electrode plate is biased with respect to the inner vessel components. Through the implementation of a CHI-dedicated gas injection system, studies in the HFS injection configuration have now demonstrated good magnetic flux evolution into the vacuum vessel. Toroidal currents up to 43 kA have been achieved, and the generated current has increased in proportion to the magnetic flux connecting the electrodes. These results which show agreement with the CHI-scaling suggest that much higher levels of toroidal current can be generated on QUEST in an optimized CHI system in which the magnetic flux connecting the CHI electrodes is further increased.

    DOI: 10.1007/s10894-022-00338-4

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  • Design Considerations for the Implementation of a High-Field-Side Transient CHI System on QUEST 招待 査読 国際誌

    Raman, R; Kuroda, K; Hanada, K; Ono, M; Hasegawa, M; Onchi, T; Ikezoe, R; Idei, H; Ido, T; Rogers, JA

    IEEE TRANSACTIONS ON PLASMA SCIENCE   50 ( 11 )   4171 - 4176   2022年11月   ISSN:0093-3813 eISSN:1939-9375

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    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:IEEE Transactions on Plasma Science  

    Transient coaxial helicity injection (T-CHI), a method first developed on the small helicity injected torus (HIT-II) experiment and then validated on the much larger National Spherical Torus Experiment (NSTX) device, is a method to initiate an inductive-like tokamak plasma discharge without reliance on the central solenoid. A CHI discharge is initiated by driving current along magnetic flux that connects the inner and outer divertor plates on one end of the tokamak. To permit this, on both HIT-II and NSTX, toroidal ceramic insulators were used to electrically separate the inner and outer vessel components. The use of such large toroidal vacuum insulators may not be easy to implement in reactors. To address this issue, the Q-shu University experiments with steady-state spherical tokamak (ST) (QUEST) is developing a reactor-relevant CHI configuration in which one of the divertor plates is electrically insulated from the rest of the vessel. The first application of T-CHI on QUEST biased the CHI electrode to the outer vessel. While the CHI discharges could be easily generated, it was found that as the discharge filled the vessel, the separation distance between the injector magnetic flux footprints widened, a condition that is not favorable for the generation of closed flux surfaces. Biasing the electrode to the inner wall is a configuration similar to that used on NSTX and HIT-II, but initial testing in this configuration has proved to be challenging. The design described here overcomes the present limitation by locating the CHI electrode much closer to the CHI injector flux coil and using an NSTX-like gas injection manifold to enable high-field-side T-CHI startup on QUEST. The concepts described in this article should also benefit the future implementation of T-CHI systems in other tokamaks and spherical tokamaks.

    DOI: 10.1109/TPS.2022.3193069

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  • Conceptual design of a heavy ion beam probe for the QUEST spherical tokamak 招待 査読 国際誌

    Ido, T; Hasegawa, M; Ikezoe, R; Onchi, T; Hanada, K; Idei, H; Kuroda, K; Nagashima, Y

    REVIEW OF SCIENTIFIC INSTRUMENTS   93 ( 11 )   113516   2022年11月   ISSN:0034-6748 eISSN:1089-7623

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    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:Review of Scientific Instruments  

    A heavy ion beam probe (HIBP) has been designed for the QUEST spherical tokamak to measure plasma turbulence and the profiles of electric potential profiles. Using a cesium ion beam with an energy of several 10 keV, the observable region covers most of the upper half of the plasma. Although the probe beam is deflected by the poloidal magnetic field produced by plasma current and poloidal coil currents, it can be detected under plasma current up to 150 kA by modifying the trajectories with two electrostatic sweepers. According to the numerical estimation of the intensity of the detected beam, sufficient signal intensity for measuring plasma turbulence can be obtained over almost the measurable area when the electron density is up to 1 × 1019 m-3, which is larger than the cut-off density of electron cyclotron heating in QUEST. The performance of the designed HIBP is sufficient to explore the mechanisms of heat and particle transport in magnetically confined plasmas, including the influence of plasma wall interactions, which is a goal of the QUEST project.

    DOI: 10.1063/5.0101770

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  • Adaptive Capon beamforming for lensless electron cyclotron emission imaging with high spatial resolution 招待 査読 国際誌

    出射 浩

    REVIEW OF SCIENTIFIC INSTRUMENTS   93 ( 10 )   103531   2022年10月   ISSN:00346748 eISSN:10897623

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    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:AIP Publishing  

    Electron cyclotron emission (ECE) imaging diagnostics incorporating a lensless approach have been developed for measurements involving active spatial selectivity and direction-of-arrival estimation. The Capon method for adaptive-array analysis was proposed to improve the spatial resolution of the two-dimensional ECE imaging technique. Broadband noise source emissions were used to simulate the ECE to verify the practical effectiveness of the Capon method in the ECE imaging. Multiple noise source emission positions were properly estimated with a high spatial resolution using the Capon method.

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  • Towards automated gas leak detection through cluster analysis of mass spectrometer data 招待 国際誌

    長谷川 真, 櫻井 大督, 東島 亜紀, 新谷 一朗, 松島 啓二, 花田 和明, 出射 浩, 井戸 毅, 池添 竜也, 恩地 拓己, 黒田 賢剛

    FUSION ENGINEERING AND DESIGN   180   113199 - 113199   2022年7月   ISSN:09203796 eISSN:1873-7196

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    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 B.V.  

    In order to generate high-performance plasma for future fusion power generation, it is desirable to keep high quality vacuum during experiment. Mass spectrometer is commonly used to monitor the vacuum quality and to record the amount of atoms and molecules in the vacuum vessel. Leak is the most serious accident to avoid that can nullify an experiment and even harm researchers. Detecting leaks are ever more important since it can be easily overlooked, e.g., when the deterioration in the vacuum degree is modest. This forces the researcher to carefully observe the vacuum and mass spectrometer data. This article presents a way to suggest potential leaks in the vacuum vessel by analyzing mass spectrometer data. This is done by utilizing the Euclidean distance between composition ratios at different times for the clustering using the daily composition ratio. We show that our cluster analysis is an effective way of separating these two cases, which results in a semi-automatic determination of leaks is more efficient than the current norm, which is to check many measures to find a small abnormality in the data manually. We plan further model improvements for long-term evaluation.

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  • Towards automated gas leak detection through cluster analysis of mass spectrometer data 招待 査読 国際誌

    @Makoto Hasegawa, @Daisuke Sakurai, @Aki Higashijima , @Ichiro Niiya, @Keiji Matsushima, @Kazuaki Hanada, @Hiroshi Idei, @Takeshi Ido, @Ryuya Ikezoe, @Takumi Onchi, @Kengo Kuroda

    Fusion Engineering and Design   180   1 - 9   2022年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Quaternion Analysis of Transient Phenomena in Matrix Converter Based on Space-Vector Modulation 招待 国際誌

    Nakamura, K; Zhang, YF; Onchi, T; Idei, H; Hasegawa, M; Tokunaga, K; Hanada, K; Chikaraishi, H; Mitarai, O; Kawasaki, S; Higashijima, A; Nagata, T; Shimabukuro, S

    PLASMA AND FUSION RESEARCH   17 ( 0 )   2405025 - 2405025   2022年4月   ISSN:18806821 eISSN:18806821

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    記述言語:英語   出版者・発行元:一般社団法人 プラズマ・核融合学会  

    The space vector of an output voltage can be rotated smoothly in a matrix converter. However, a zerosequence component appears causing problems in the load, such as a motor. A quaternion is a four-dimensional hypercomplex number with an imaginary part that can simultaneously represent and deal with three-phase voltages. In addition, the quaternion is expressed in the exponential form; thus, it can easily represent the space vector rotation. Two zero configurations were used to optimize the ripple characteristics in fictitious pulse-widthmodulated voltage-source inverter. The two zero configurations are used to remove the zero-sequence component from the matrix converter. The quaternion can be differentiated in time as well as rotate in space. Therefore, it is used to analyze transient phenomena in the matrix converter’s rise-up and rise-down phases, and the switching’s transition phase.

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  • Overview of coordinated spherical tokamak research in Japan 招待 査読 国際誌

    Takase, Y; Ejiri, A; Fujita, T; Hanada, K; Idei, H; Nagata, M; Onchi, T; Ono, Y; Tanaka, H; Tsujii, N; Uchida, M; Yasuda, K; Kasahara, H; Murakami, S; Takeiri, Y; Todo, Y; Tsuji-Iio, S; Kamada, Y

    NUCLEAR FUSION   62 ( 4 )   2022年4月   ISSN:0029-5515 eISSN:1741-4326

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    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:Nuclear Fusion  

    Spherical tokamak (ST) research in Japan has produced many innovative results: (i) plasma start-up to I p > 70 kA was achieved by electron cyclotron wave (ECW) with N ∥ = 0.75, while electron heating to T e > 500 eV was achieved with N ∥ = 0.26 on QUEST. (ii) The radiofrequency (RF)-induced transport model was combined with the x-ray emission model, and extended magnetohydrodynamics equilibrium with kinetic electrons was developed to interpret fast-electron-dominated lower hybrid wave sustained plasmas on TST-2. (iii) Density as high as 30 times the cutoff density was achieved by electron Berstein wave current drive combined with electron beam injection on LATE. (iv) Multiple plasmoids formed by tearing instability in the elongated current sheet were observed, and flux closure and ion heating by plasmoid-mediated fast magnetic reconnection were observed on HIST. (v) Optimization of ECW-assisted inductive start-up with a vertical field with positive decay index was performed on TST-2. (vi) Stabilization of the vertical displacement event by a set of upper and lower helical field coils was demonstrated on TOKASTAR-2. (vii) A 6 h discharge was achieved by cool-down of the center stack cover on QUEST, where the plasma duration limit was consistent with the wall saturation time estimated by modeling. (viii) Extension of ion heating by plasma merging was achieved on TS-3U, TS-4U, UTST, MAST, and ST40.

    DOI: 10.1088/1741-4326/ac29cf

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  • Quaternion Analysis of Transient Phenomena in Matrix Converter Based on Space-Vector Modulation 招待 査読 国際誌

    Kazuo NAKAMURA, Yifan ZHANG1), Takumi ONCHI, Hiroshi IDEI, Makoto HASEGAWA, Kazutoshi TOKUNAGA, Kazuaki HANADA, Hirotaka CHIKARAISHI2), Osamu MITARAI3), Shoji KAWASAKI, Aki HIGASHIJIMA, Takahiro NAGATA and Shun SHIMABUKURO

    Plasma and Fusion Research   2022年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: DOI: 10.1585/pfr.17.2405025

  • Observation of second harmonic electron cyclotron resonance heating and current-drive transition during non-inductive plasma start-up experiment in QUEST 招待 査読 国際誌

    Kojima, Shinichiro; Hanada, Kazuaki; Idei, Hiroshi; Onchi, Takumi; Ikezoe, Ryuya; Nagashima, Yoshihiko; Hasegawa, Makoto; Kuroda, Kengoh; Nakamura, Kazuo; Higashijima, Aki; Nagata, Takahiro; Kawasaki, Shoji; Shimabukuro, Shun; Elserafy, Hatem; Fukuyama, Masaharu; Ejiri, Akira; Shikama, Taiichi; Yoneda, Nao; Yoneda, Ryota; Kariya, Tsuyoshi; Takase, Yuichi; Murakami, Sadayoshi; Bertelli, Nicola; Ono, Masayuki

    PLASMA PHYSICS AND CONTROLLED FUSION   63 ( 10 )   2021年10月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1088/1361-6587/ac1838

  • MHD Equilibrium Reconstruction Using the Visible Light Tomographic Method with Laplacian Eigenfunction 査読 国際誌

    Kosuke Suzuki, Sadayoshi Murakami, Satoshi Ohdachi, Hiroshi Idei, Kengoh Kuroda, Ryuya Ikezoe, Takumi Onchi

    Plasma and Fusion Research   2021年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Designing an upgrade of ohmic heating system for the QUEST spherical tokamak 査読 国際誌

    #Yifan Zhang, @Takumi Onchi, @Kazuo Nakamura, #Akihiro Kidani, #Qilin Yue, @Kengoh Kuroda, @Makoto Hasegawa, @Ryuya Ikezoe, @Hiroshi Idei

    Fusion Engineering and Design   168   112362   2021年7月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

  • Overview of recent progress on steady state operation of all-metal plasma facing wall device QUEST 招待 査読 国際誌

    Hanada, K.; Yoshida, N.; Hasegawa, M.; Oya, M.; Oya, Y.; Takagi, I; Hatayama, A.; Shikama, T.; Idei, H.; Nagashima, Y.; Ikezoe, R.; Onchi, T.; Kuroda, K.; Kawasaki, S.; Higashijima, A.; Nagata, T.; Shimabukuro, S.; Nakamura, K.; Murakami, S.; Takase, Y.; Gao, X.; Liu, H.; Qian, J.

    NUCLEAR MATERIALS AND ENERGY   27   2021年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.nme.2021.101013

  • Investigation of radial distribution of atomic hydrogen flux to the plasma facing components in steady state discharges in QUEST tokamak 査読 国際誌

    Kuzmin, A.; Kobayashi, M.; Hanada, K.; Idei, H.; Onchi, T.; Mori, S.; Yoneda, N.; Shikama, T.; Hasuo, M.; Ido, T.; Nagashima, Y.; Ikezoe, R.; Hasegawa, M.; Kuroda, K.; Kono, K.; Matsuo, S.; Nagata, T.; Shimabukuro, S.; Higashijima, A.; Niiya, I; Zushi, H.

    NUCLEAR MATERIALS AND ENERGY   26   100872   2021年3月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.nme.2020.100872

  • Toroidal flow measurements of impurity ions in QUEST ECH plasmas using multiple viewing chords emission spectroscopy 査読 国際誌

    N Yoneda, T Shikama, K Hanada, S Mori, Takumi Onchi, K Kuroda, M Hasuo, A Ejiri, K Matsuzaki, Y Osawa, Y Peng, Y Kawamata, S Sakamoto, H Idei, T Ido, K Nakamura, Y Nagashima, Ryuya Ikezoe, M Hasegawa, A Higashijima, T Nagata, S Shimabukuro

    Nuclear Materials and Energy   26 ( 3 )   100905-1 - 100905-7   2021年3月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: https://doi.org/10.1016/j.nme.2021.100905

  • Effects of Toroidally Distributed Divertor Biasing on Scrape-Off-Layer Plasma in the QUEST Spherical Tokamak 査読 国際誌

    Kazuo TOI, Takumi ONCHI, Kengo KURODA, Shinichiro KOJIMA, Hideki ZUSHI, Makoto HASEGAWA, Masaharu FUKUYAMA, Shoji KAWASAKI, Aki HIGASHIJIMA, Ryuya IKEZOE, Hiroshi IDEI, Takeshi IDO, Kazuaki HANADA, QUEST Experiment Group

    Plasma and Fusion Research   16   2021年3月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: https://doi.org/10.1585/pfr.16.2402024

  • Extension of Operation Region for Steady State Operation on QUEST by Integrated Control with Hot Walls 招待 査読 国際誌

    Makoto HASEGAWA, Kazuaki HANADA, Naoaki YOSHIDA, Hiroshi IDEI, Takeshi IDO, Yoshihiko NAGASHIMA, Ryuya IKEZOE, Takumi ONCHI, Kengoh KURODA, Shoji KAWASAKI, Aki HIGASHIJIMA, Takahiro NAGATA, Shun SHIMABUKURO, Kazuo NAKAMURA

    Plasma and Fusion Research   16   2021年3月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: https://doi.org/10.1585/pfr.16.2402034

  • Quaternion Analysis of a Direct Matrix Converter Based on Space-Vector Modulation 査読 国際誌

    Kazuo Nakamura, Yifan Zhang, Takumi Onchi, Hiroshi Idei, Makoto Hasegawa, Kazutoshi Tokunaga, Kazuaki Hanada, Osamu Mitarai, Shoji Kawasaki, Aki Higashijima, Takahiro Nagata, Shun Shimabukuro

    Plasma and Fusion Research   16   2405037 - 2405037   2021年3月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

  • Spectroscopic Measurement of Hydrogen Atom Density in a Plasma Produced with 28 GHz ECH in QUEST 査読 国際誌

    Satoru Mori, Taiichi Shikama, Kazuaki Hanada, Nao Yoneda, Arseniy Kuzmin, Masahiro Hasuo, Hiroshi Idei, Takumi Onchi, Akira Ejiri, Yuki Osawa, Yi Peng, Kyohei Matsuzaki, Shinichiro Kado, Keiji Sawada, Takeshi Ido, Kazuo Nakamura, Ryuya Ikezoe, Yoshihiko Nagashima, Makoto Hasegawa, Kengo Kuroda, Aki Higashijima, Takahiro Nagata, Shun Shimabukuro

    Atoms   8 ( 3 )   44-1 - 44-8   2020年9月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: https://doi.org/10.1585/pfr.15.2402063

  • Modeling of solenoid-free start-up using 2nd harmonic electron cyclotron heating and current drive in QUEST 査読 国際誌

    M Ono, N Bertelli, H Idei, K Hanada, Takumi Onchi, S Kojima, H Elserafy

    AIP Conference Proceedings   2254 ( 1 )   090001   2020年9月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

  • Parametric Decay Wave Observation in HFS X-Mode Injection in QUEST 査読 国際誌

    Shinichiro Kojima, Hatem Elserafy, Kazuaki Hanada, Hiroshi Idei, Ryuya Ikezoe, Yoshihiko Nagashima, Makoto Hasegawa, Takumi Onchi, Kengoh Kuroda, Kazuo Nakamura, Takahiro Murakami, Masaharu Fukuyama, Ryoya Kato, Ryota Yoneda, Masayuki Ono, Akira Ejiri, Yuichi Takase, Sadayoshi Murakami

    Plasma and Fusion Research   15   2402063-1 - 2402063-2   2020年8月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: https://doi.org/10.1585/pfr.15.2402063

  • Predictive maintenance and safety operation by device integration on the QUEST large experimental device 査読 国際誌

    @Makoto Hasegawa, @Kazuaki Hanada, @Hiroshi Idei, @Shoji Kawasaki, @Takahiro Nagata, @Ryuya Ikezoe, @Takumi Onchi, @Kengoh Kuroda, @Aki Higashijima

    Heliyon   6 ( 6 )   e04214   2020年6月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.heliyon.2020.e04214

  • Measurement of Dynamic Retention with Fast Ejecting System of Targeted Sample (FESTA) 招待 査読 国際誌

    #Qilin YUE, @Kazuaki HANADA, @Makoto OYA, Shogo MATSUO, #Shinichiro KOJIMA, @Hiroshi IDEI, @Takumi ONCHI, @Kengoh KURODA, @Naoaki YOSHIDA, @Ryuya IKEZOE, Yukai LIU, @Makoto HASEGAWA, @Shun SHIMABUKURO, @Aki HIGASHIJIMA, @Takahiro NAGATA and @Shoji KAWASAKI

    Plasma and Fusion Research   15 ( 2402013 )   2402013-1 - 2402013-5   2020年4月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1585/pfr.15.2402013

  • Electron heating of over-dense plasma with dual-frequency electron cyclotron waves in fully non-inductive plasma ramp-up on the QUEST spherical tokamak 査読

    H. Idei, T. Onchi, K. Mishra, H. Zushi, T. Kariya, T. Imai, O. Watanabe, R. Ikezoe, K. Hanada, M. Ono, A. Ejiri, J. Qian, K. Nakamura, A. Fujisawa, Y. Nagashima, M. Hasegawa, K. Matsuoka, A. Fukuyama, S. Kubo, M. Yoshikawa, M. Sakamoto, S. Kawasaki, A. Higashijima, S. Ide, Y. Takase, S. Murakami

    Nuclear Fusion   60 ( 1 )   2020年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1088/1741-4326/ab4c12

  • Electron Bernstein wave conversion of high-field side injected X-modes in QUEST 査読

    Hatem Elserafy, Kazuaki Hanada, Shinichiro Kojima, Takumi Onchi, Ryuya Ikezoe, Kengoh Kuroda, Hiroshi Idei, Makoto Hasegawa, Ryota Yoneda, Masaharu Fukuyama, Arseniy Kuzmin, Aki Higashijima, Takahiro Nagata, Shoji Kawasaki, Shun Shimabukuro, Nicola Bertelli, Masayuki Ono

    Plasma Physics and Controlled Fusion   62 ( 3 )   2020年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1088/1361-6587/ab6903

  • Quasi-optical polarizer system for ECHCD experiments in the QUEST 査読

    M. Fukuyama, Hiroshi Idei, T. I. Tsujimura, S. Kubo, S. Kobayashi, M. Yunoki, Takumi Onchi, Ryuya Ikezoe

    Fusion Engineering and Design   146   1437 - 1440   2019年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.fusengdes.2019.02.099

  • Plasma equilibrium based on EC-driven current profile with toroidal rotation on QUEST 査読

    K. Nakamura, M. M. Alam, Y. Z. Jiang, O. Mitarai, M. Takechi, M. Hasegawa, K. Tokunaga, K. Hanada, H. Idei, Y. Nagashima, T. Onchi, K. Kuroda, O. Watanabe, A. Higashijima, T. Nagata, S. Shimabukuro, S. Kawasaki, A. Fukuyama

    Fusion Engineering and Design   146   2628 - 2631   2019年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.fusengdes.2019.04.059

  • High voltage electrical system of 8.56 GHz CW klystron for electron cyclotron heating on QUEST spherical tokamak 査読

    Takumi Onchi, Hiroshi Idei, K. Nakamura, T. Nagata, S. Kawasaki, R. Ashida, M. Fukuyama, Makoto Hasegawa, Ryuya Ikezoe, A. Higashijima, K. Kuroda, Yoshihiko Nagashima, Kazuaki Hanada

    Fusion Engineering and Design   146   2567 - 2570   2019年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.fusengdes.2019.04.043

  • Particle balance investigation with the combination of the hydrogen barrier model and rate equations of hydrogen state in long duration discharges on an all-metal plasma facing wall in QUEST 査読

    K. Hanada, N. Yoshida, M. Hasegawa, A. Hatayama, K. Okamoto, I. Takagi, T. Hirata, Y. Oya, M. Miyamoto, M. Oya, T. Shikama, A. Kuzmin, Z. X. Wang, H. Long, H. Idei, Y. Nagashima, K. Nakamura, O. Watanabe, T. Onchi, H. Watanabe, K. Tokunaga, A. Higashijima, S. Kawasaki, T. Nagata, S. Shimabukuro, Y. Takase, S. Murakami, X. Gao, H. Liu, J. Qian, R. Raman, M. Ono

    Nuclear Fusion   59 ( 7 )   2019年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1088/1741-4326/ab1858

  • Estimation of fuel particle balance in steady state operation with hydrogen barrier model 査読

    Kazuaki Hanada, N. Yoshida, I. Takagi, T. Hirata, A. Hatayama, K. Okamoto, Y. Oya, T. Shikama, Z. Wang, H. Long, C. Huang, M. Oya, Hiroshi Idei, Yoshihiko Nagashima, Takumi Onchi, Makoto Hasegawa, K. Nakamura, H. Zushi, K. Kuroda, S. Kawasaki, A. Higashijima, T. Nagata, S. Shimabukuro, Y. Takase, S. Murakami, X. Gao, H. Liu, J. Qian, R. Raman, M. Ono

    Nuclear Materials and Energy   19   544 - 549   2019年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.nme.2019.03.015

  • Development of high power gyrotrons for advanced fusion devices 査読

    T. Kariya, R. Minami, T. Imai, M. Okada, F. Motoyoshi, T. Numakura, Y. Nakashima, Hiroshi Idei, Takumi Onchi, Kazuaki Hanada, T. Shimozuma, Y. Yoshimura, H. Takahashi, S. Kubo, Y. Oda, R. Ikeda, K. Sakamoto, M. Ono, K. Nagasaki, T. Eguchi, Y. Mitsunaka

    Nuclear Fusion   59 ( 6 )   2019年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1088/1741-4326/ab0e2c

  • Prototype phased-array patch loop antennae for electron cyclotron emission diagnostics 査読

    Masaharu Fukuyama, Hiroshi Idei, Miu Yunoki, Ryuichi Ashida, Daichi Ogata, Ryuya Ikezoe, Takumi Onchi

    Plasma and Fusion Research   14   2019年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1585/PFR.14.3402111

  • Improvement of aperture configuration to reduce the stray light for Thomson scattering measurement using a peripheral beam profile monitor 査読

    Yuya Kawamata, Akira Ejiri, Kyohei Matsuzaki, Yuichi Takase, Naoto Tsujii, Takumi Onchi, Yoshihiko Nagashima

    Plasma and Fusion Research   14   2019年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1585/PFR.14.1402072

  • HFS injection of X-mode for EBW conversion in QUEST 査読

    Hatem Elserafy, Kazuaki Hanada, Kengoh Kuroda, Hiroshi Idei, Ryota Yoneda, Canbin Huang, Shinichiro Kojima, Makoto Hasegawa, Yoshihiko Nagashima, Takumi Onchi, Ryuya Ikezoe, Aki Higashijima, Takahiro Nagata, Shoji Kawasaki, Shun Shimabukuro, Nicola Bertelli, Masayuki Ono

    Plasma and Fusion Research   14 ( 1 )   2019年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1585/pfr.14.1205038

  • 28-GHz ECHCD system with beam focusing launcher on the QUEST spherical tokamak 査読

    Hiroshi Idei, Takumi Onchi, T. Kariya, T. I. Tsujimura, S. Kubo, S. Kobayashi, M. Sakaguchi, T. Imai, Makoto Hasegawa, K. Nakamura, K. Mishra, M. Fukuyama, M. Yunoki, S. Kojima, O. Watanabe, K. Kuroda, Kazuaki Hanada, Yoshihiko Nagashima, A. Ejiri, N. Matsumoto, M. Ono, A. Higashijima, T. Nagata, S. Shimabukoro, Y. Takase, A. Fukuyama, S. Murakami

    Fusion Engineering and Design   2019年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.fusengdes.2019.02.027

  • Initial results from solenoid-free plasma start-up using Transient CHI on QUEST 査読

    K. Kuroda, R. Raman, Kazuaki Hanada, Makoto Hasegawa, Takumi Onchi, M. Ono, B. A. Nelson, T. R. Jarboe, M. Nagata, O. Mitarai, K. Nakamura, Hiroshi Idei, J. Rogers, S. Kawasaki, T. Nagata, A. Kuzmin, S. Kojima, C. Huang, O. Watanabe, A. Higashijima, Y. Takase, A. Fukuyama, S. Murakami

    Plasma Physics and Controlled Fusion   60 ( 11 )   2018年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1088/1361-6587/aadcb7

  • Effect of magnetic shear on edge turbulence in SOL-like open field line configuration in QUEST 査読

    Santanu Banerjee, H. Zushi, N. Nishino, Kazuaki Hanada, Hiroshi Idei, K. Nakamura, Makoto Hasegawa, akihide fujisawa, Yoshihiko Nagashima, K. Mishra, S. Tashima, Takumi Onchi, A. Kuzmin, K. Matsuoka

    Plasma Physics and Controlled Fusion   60 ( 8 )   2018年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1088/1361-6587/aacb69

  • Modification of plasma control system and hot-wall temperature control system for long-duration plasma sustainment in QUEST 査読

    Makoto Hasegawa, Kazuo Nakamura, Kazuaki Hanada, Shoji Kawasaki, Arseniy Kuzmin, Hiroshi Idei, Kazutoshi Tokunaga, Yoshihiko Nagashima, Takumi Onchi, Kengoh Kuroda, Osamu Watanabe, Aki Higashijima, Takahiro Nagata

    Fusion Engineering and Design   129   202 - 206   2018年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.fusengdes.2018.02.069

  • Spectroscopic measurements of impurity ion toroidal and poloidal flow velocities and their dependence on vertical magnetic field in QUEST toroidal ECR plasmas 査読

    Nao Yoneda, Taiichi Shikama, Hideki Zushi, Kazuaki Hanada, Akinobu Fujikawa, Takumi Onchi, Kengoh Kuroda, Kuniaki Nii, Masahiro Hasuo, Makoto Hasegawa, Hiroshi Idei, Kazuo Nakamura, Yoshihiko Nagashima, Aki Higashijima, Takahiro Nagata

    Plasma and Fusion Research   13   2018年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1585/PFR.13.3402087

  • Fully non-inductive second harmonic electron cyclotron plasma ramp-up in the QUEST spherical tokamak 査読

    Hiroshi Idei, T. Kariya, T. Imai, K. Mishra, Takumi Onchi, O. Watanabe, H. Zushi, Kazuaki Hanada, J. Qian, A. Ejiri, M. M. Alam, K. Nakamura, akihide fujisawa, Yoshihiko Nagashima, Makoto Hasegawa, K. Matsuoka, A. Fukuyama, S. Kubo, T. Shimozuma, M. Yoshikawa, M. Sakamoto, S. Kawasaki, H. Nakashima, A. Higashijima, S. Ide, T. Maekawa, Y. Takase, K. Toi

    Nuclear Fusion   57 ( 12 )   2017年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1088/1741-4326/aa7c20

  • Momentum injection and repetitive CT operation experiments 査読

    C. Xiao, A. Rohollahi, Takumi Onchi, M. Dreval, S. Elgriw, A. Hirose

    Radiation Effects and Defects in Solids   172 ( 9-10 )   713 - 717   2017年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1080/10420150.2017.1398244

  • Investigation of hydrogen recycling in long-duration discharges and its modification with a hot wall in the spherical tokamak QUEST 査読

    Kazuaki Hanada, N. Yoshida, T. Honda, Z. Wang, A. Kuzmin, I. Takagi, T. Hirata, Y. Oya, M. Miyamoto, H. Zushi, Makoto Hasegawa, K. Nakamura, akihide fujisawa, Hiroshi Idei, Yoshihiko Nagashima, O. Watanabe, Takumi Onchi, K. Kuroda, H. Long, Hideo Watanabe, Kazutoshi Tokunaga, A. Higashijima, S. Kawasaki, T. Nagata, Y. Takase, A. Fukuyama, O. Mitarai

    Nuclear Fusion   57 ( 12 )   2017年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1088/1741-4326/aa8121

  • Spatial distribution of atomic and ion hydrogen flux and its effect on hydrogen recycling in long duration confined and non-confined plasmas 査読

    A. Kuzmin, H. Zushi, I. Takagi, S. K. Sharma, M. Kobayashi, Y. Hirooka, Takumi Onchi, Kazuaki Hanada, N. Yoshida, K. Nakamura, akihide fujisawa, Hiroshi Idei, Yoshihiko Nagashima, Makoto Hasegawa, T. Mutoh, K. Mishra, H. Ohwada

    Nuclear Materials and Energy   12   627 - 632   2017年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.nme.2017.03.027

  • Comparative studies of inner and outer divertor discharges and a fueling study in QUEST 招待 査読 国際誌

    O. Mitarai, K. Nakamura, M. Hasegawa, T. Onchi, H. Idei, A. Fujisawa, K. Hanada, H. Zushi, A. Higashijima, H. Nakashima, S. Kawasaki, K. Matsuoka, S. Koike, T. Takahashi, H. Tsutsui

    FUSION ENGINEERING AND DESIGN   109   1365 - 1370   2016年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.fusengdes.2015.12.022

  • Response of the far scrape-off layer plasma to strong gas puffing in the high poloidal beta configuration of the QUEST spherical tokamak 招待 査読 国際誌

    T. Onchi, H. Zushi, K. Mishra, Y. Oyama, Y. Nagashima, K. Hanada, H. Idei, M. Hasegawa, A. Kuzmin, H. Miura, K. Nakamura, A. Fujisawa, K. Nagaoka

    PLASMA PHYSICS AND CONTROLLED FUSION   58 ( 11 )   2016年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1088/0741-3335/58/11/115004

  • Observation of an edge coherent mode and poloidal flow in the electron cyclotron wave induced high beta(p) plasma in QUEST 招待 査読 国際誌

    S. Banerjee, H. Zushi, N. Nishino, K. Mishra, K. Mahira, S. Tashima, A. Ejiri, T. Yamaguchi, T. Onchi, Y. Nagashima, K. Hanada, K. Nakamura, H. Idei, M. Hasegawa, A. Fujisawa, A. Kuzmin, K. Matsuoka

    PHYSICS OF PLASMAS   23 ( 8 )   2016年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1063/1.4960117

  • Hydrogen flux measurements with permeation probes in spherical tokamak QUEST 査読 国際誌

    A Kuzmin, H Zushi, I Takagi, SK Sharma, Y Hirooka, M Kobayashi, M Sakamoto, K Hanada, T Onchi, Y Oyama, N Youshida, K Nakamura, A Fujisawa, H Idei, Y Nagashima, M Hasegawa, K Mishra

    Vacuum   129   2016年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Adaptive-array Electron Cyclotron Emission diagnostics using data streaming in a Software Defined Radio system 査読 国際誌

    H Idei, K Mishra, MK Yamamoto, M Hamasaki, A Fujisawa, Y Nagashima, Y Hayashi, T Onchi, K Hanada, H Zushi

    Journal of Instrumentation   11 ( 4 )   2016年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Tomography as a promising diagnostic tool for plasma turbulence 査読 国際誌

    A Fujisawa, Y Nagashima, S Inagaki, T Onchi, S Ohshima, A Shimizu

    Plasma Physics and Controlled Fusion   58 ( 2 )   2016年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Multiple wall-reflection effect in adaptive-array differential-phase reflectometry on QUEST 査読 国際誌

    H Idei, K Mishra, MK Yamamoto, A Fujisawa, Y Nagashima, M Hamasaki, Y Hayashi, T Onchi, K Hanada, H Zushi

    Journal of Instrumentation   11 ( 1 )   2016年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Comparative studies of inner and outer divertor discharges and a fueling study in QUEST 査読 国際誌

    O Mitarai, K Nakamura, M Hasegawa, T Onchi, H Idei, A Fujisawa, K Hanada, H Zushi, A Higashijima, H Nakashima, S Kawasaki, K Matsuoka, S Koike, T Takahashi, H Tsutsui

    Fusion Engineering and Design   2015年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Global gas balance and influence of atomic hydrogen irradiation on the wall inventory in steady-state operation of QUEST tokamak 査読 国際誌

    A. Kuzmin, H. Zushi, I. Takagi, S.K. Sharma, A. Rusinov, Y. Inoue, Y. Hirooka, H. Zhou, M. Kobayashi, M. Sakamoto, K. Hanada, N. Yoshida, K. Nakamura, A. Fujisawa, K. Matsuoka, H. Idei, Y. Nagashima, M. Hasegawa, T. Onchi, S. Banerjee, K. Mishra

    Journal of Nuclear Materials   463   2015年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Heat flux and plasma flow in the far scrape-off layer of the inboard poloidal field null configuration in QUEST 査読 国際誌

    T. Onchi, H. Zushi, K. Mishra, Y. Mahira, K. Nagaoka, K. Hanada, H. Idei, M. Hasegawa, K. Nakamura, A. Fujisawa, Y. Nagashima, K. Matsuoka, S. Tashima, S. Banerjee, A. Kuzmin, S. Kawasaki, H. Nakashima, A. Higashijima, O. Watanabe

    Physics of Plasmas   22 ( 8 )   2015年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Self organization of high βp plasma equilibrium with an inboard poloidal magnetic field null in QUEST 査読 国際誌

    55 ( 8 )   2015年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Observation of heat flux and plasma flow in scrape off layer in QUEST 査読 国際誌

    T. Onchi, Y. Mahira, K. Nagaoka, S. Tashima, S. Banerjee, K. Mishra, H. Idei, K. Hanada, K. Nakamura, A. Fujisawa, Y. Nagashima, M. Hasegawa, K. Matsuoka, A. Kuzmin, O. Watanabe, S. Kawasaki, H. Nakashima, A. Higashijima

    Journal of Nuclear Materials   463   2015年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Particle balance in long duration RF driven plasmas on QUEST 査読

    K. Hanada, H. Zushi, N. Yoshida, N. Yugami, T. Honda, M. Hasegawa, K. Mishra, A. Kuzmin, K. Nakamura, A. Fujisawa, H. Idei, Y. Nagashima, O. Watanabe, T. Onchi, H. Watanabe, K. Tokunaga, A. Higashijima, S. Kawasaki, H. Nakashima, Y. Takase, A. Fukuyama, O. Mitarai, Y.K.M. Peng

    Journal of Nuclear Materials   463   2015年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Dynamical programming based turbulence velocimetry for fast visible imaging of tokamak plasma 査読 国際誌

    S. Banerjee, H. Zushi, N. Nishino, K. Mishra, T. Onchi, A. Kuzmin, Y. Nagashima, K. Hanada, K. Nakamura, H. Idei, M. Hasegawa, A. Fujisawa

    Review of Scientific Instruments   86 ( 3 )   2015年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Thermal imaging of plasma with a phased array antenna in QUEST 査読 国際誌

    K. Mishra, H. Idei, H. Zushi, K. Nagata, R. Akimoto, M. K. Yamamoto, K. Hanada, M. Hasegawa, K. Nakamura, A. Fujisawa, Y. Nagashima, S. Banerjee, T. Onchi, A. Kuzmin

    Review of Scientific Instruments   85 ( 11 )   2014年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • A prototype diagnostics system to detect ultraviolet emission for plasma turbulence 査読 国際誌

    T. Onchi, A. Fujisawa, A. Sanpei

    Review of Scientific Instruments   85 ( 11 )   2014年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Design and implementation of fast charging circuit for repetitive compact torus injector 査読 国際誌

    T. Onchi, D. McColl, M. Dreval, S. Wolfe, C. Xiao, A. Hirose

    Fusion Engineering and Design   89 ( 11 )   2014年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Plasma current sustainment after iron core saturation in the STOR-M tokamak 査読 国際誌

    O. Mitarai, Y. Ding, M. Hubeny, Y. Lu, T. Onchi, D. McColl, C. Xiao, A. Hirose

    Fusion Engineering and Design   89 ( 9-10 )   2014年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Plasma confinement modification and convective transport suppression in the scrape-off layer using additional gas puffing in the STOR-M tokamak 査読 国際誌

    M. Dreval, M. Hubeny, Y. Ding, T. Onchi, Y. Liu, K. Hthu, S. Elgriw, C. Xiao, A. Hirose

    Plasma Physics and Controlled Fusion   55 ( 3 )   2013年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Asymmetric toroidal flux generation due to phase locking of internally resonant tearing modes in the RELAX reversed-field pinch 査読 国際誌

    R. Ikezoe, S. Masamune, K. Oki, A. Sanpei, H. Himura, T. Onchi, A. Hirose

    Plasma Physics and Controlled Fusion   55 ( 1 )   2013年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Phase Locking and Unlocking Associated with Transition to Quasi-Single Helicity State in the RELAX Reversed-Field Pinch 査読 国際誌

    R. Ikezoe, S. Masamune, K. Oki, A. Sanpei, H. Himura, T. Onchi, A. Hirose

    Journal of the Physical Society of Japan   81 ( 11 )   2012年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Modification of toroidal flow in the STOR-M tokamak 国際誌

    C. Xiao, S. Elgriw, Y. Liu, T. Onchi, M. Dreval, M. Hubeny, Y. Ding, T. Asai, A. Hirose

    Proc. 24th Int. Conf. on Fusion Energy (San Diego, CA, 2012)   2012年10月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

  • Design and Initial Result of Time-Resolved Vertical Soft X-Ray Imaging System in Low-A RFP 査読 国際誌

    A. Sanpei, K. Oki, D. Fukahori, K. Deguchi, S. Nakaki, K. Nishimura, H. Himura, S. Masamune, S. Ohdachi, N. Nishino, T. Onchi

    Plasma and Fusion Research   7   2012年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Fuelling Effect of Tangential Compact toroid injection in STOR-M Tokamak 査読 国際誌

    T. Onchi, Y. Liu, M. Dreval, D. McColl, T. Asai, S. Wolfe, C. Xiao and A. Hirose

    CNS(Canadian Nuclear Society)2012 conference paper   2012年6月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

  • Recent Experiments on the STOR-M Tokamak 査読 国際誌

    C. Xiao, T.Onchi, Y. Liu, S. Elgriw, M.Dreval, D. McColl, T. Asai, and A. Hirose

    CNS(Canadian Nuclear Society)2012 conference paper   2012年6月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

  • Tangential Image of Helical SXR Emissivity Structure in Low-Aspect-Ratio RFP 査読 国際誌

    A. Sanpei, K. Oki, M. Nakamura, A. Higashi, H. Motoi, D. Fukahori, H. Himura, S. Masamune, S. Ohdachi, N. Nishino, T. Onchi, R. Ikezoe

    Plasma Science, IEEE Transactions on   39 ( 11 )   2011年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Observation of Helical Structure by Imaging Diagnostics in a Low-Aspect-Ratio Reversed Field Pinch 査読 国際誌

    T. Onchi, R. Ikezoe, K. Oki, A. Sanpei, H. Himura, S. Masamune, N. Nishino, H. Koguchi

    Journal of the Physical Society of Japan   80 ( 11 )   2011年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Initial Result of Successive SXR Imaging Measurement in Low-A RFP 査読 国際誌

    A. SANPEI, K. OKI, M. NAKAMURA, A. HIGASHI, H. MOTOI, D. FUKAHORI, H. HIMURA, S. MASAMUNE, S. OHDACHI, N. NISHINO, T. ONCHI, R. IKEZOE

    Plasma and Fusion Research   6   2011年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Extended operational regimes and MHD behavior in a low-aspect-ratio reversed field pinch in RELAX 査読 国際誌

    R. Ikezoe, K. Oki, T. Onchi, Y. Konishi, M. Sugihara, S. Fujita, A. Sanpei, H. Himura, S. Masamune

    Plasma Physics and Controlled Fusion   53 ( 2 )   2011年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Density Regimes of Low-Aspect-Ratio RFP Plasmas in RELAX 査読 国際誌

    M. Sugihara, K. Oki, R. Ikezoe, T. Onchi, A. Sanpei, H. Himura, S. Masamune, T. Akiyama, A. Ejiri, K. Sakamoto, K. Nagasaki, V. Zhuravlev

    Plasma and Fusion Research   5   2010年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Recent Progress in Low-A RFP Plasma Research in RELAX 査読 国際誌

    A. Sanpei, R. Ikezoe, T. Onchi, K. Oki, M. Sugihara, Y. Konishi, S. Fujita, M. Nakamura, A. Higashi, H. Motoi, H. Himura, S. Masamune

    Plasma and Fusion Research   5   2010年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • MHD Properties of Low-aspect Ratio RFP in RELAX 査読 国際誌

    S Masamune, A Sanpei, R Ikezoe, T Onchi, K Oki, T Yamashita, H Shimazu, H Himura, R Paccagnella

    Journal of fusion energy   28 ( 2 )   2009年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Equilibrium Reconstruction and Estimation of Neoclassical Effect in Low-Aspect-Ratio Reversed Field Pinch Experiments on RELAX 査読 国際誌

    Akio Sanpei, Kensuke Oki, Ryuya Ikezoe, Takumi Onchi, Ken-Ichi Murata, Hiroyuki Shimazu, Tetsuo Yamashita, Shinichi Fujita, Haruhiko Himura, Sadao Masamune, Jay K Anderson

    Journal of the Physical Society of Japan   78 ( 1 )   2009年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Effects of Loowering the Aspect Ratio on MHD Behaviour in a Reversed Field Pinch 国際誌

    S. Masamune, A. Sanpei, R. Ikezoe, T. Onchi, K. Oki, T. Yamashita, H. Shimazu, K. Murata, H. Himura, N. Nishino, R. Paccagnella

    Proc. 22th Int. Conf. on Fusion Energy (Geneva, 2008)   2008年10月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

  • Observation of large-scale profile change of magnetic field in a low-aspect ratio reversed field pinch 査読 国際誌

    Kensuke Oki, Ryuya Ikezoe, Takumi Onchi, Akio Sanpei, Haruhiko Himura, Sadao Masamune, Roberto Paccagnella

    Journal of the Physical Society of Japan   77 ( 7 )   2008年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Quasi-periodic growth of a single helical instability in a low-aspect ratio RFP 査読 国際誌

    Ryuya Ikezoe, Takumi Onchi, Kensuke Oki, Akio Sanpei, Haruhiko Himura, Sadao Masamune

    Plasma and Fusion Research   3   2008年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Observation of Simple Helical Structure in Low Aspect Ratio RFP Using Fast Camera 査読 国際誌

    Takumi Onchi, Nobuhiro Nishino, Ryuya Ikezoe, Akio Sanpei, Haruhiko Himura, Sadao Masamune

    Plasma and Fusion Research   3   2008年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Application of Soft X-Ray Imaging System to the STE-2 RFP 査読 国際誌

    Takumi Onchi, Akio Sanpei, Ryuya Ikezoe, Haruhiko Himura, Sadao Masamune

    Plasma and Fusion Research   2   2007年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Characterization of Initial Low-Aspect Ratio RFP Plasmas in “RELAX” 査読 国際誌

    76 ( 12 )   2007年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Design of Soft-X Ray Imaging System for Magnetic Islands of RFP Plasmas 査読 国際誌

    Akio Sanpei, Takumi Onchi, Ryuya Ikezoe, Haruhiko Himura, Sadao Masamune

    Plasma and Fusion Research   2   2007年11月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Research plans for low-aspect ratio reversed field pinch 査読 国際誌

    S Masamune, A Sanpei, H Himura, R Ikezoe, T Onchi, M Nagata, H Hiramatsu, D Ishijima

    Fusion science and technology   51 ( 2 )   1900年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Characterization of equilibria in a low-aspect-ratio RFP 査読 国際誌

    Akio Sanpei, Kensuke Oki, Ryuya Ikezoe, Takumi Onchi, Hiroyuki Shimazu, Tetsuo Yamashita, Haruhiko Himura, Sadao Masamune

    Journal of Plasma Fusion Research SERIES   8   1900年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

▼全件表示

講演・口頭発表等

  • TASK/WRを用いたQUEST電流立ち上げ実験の28GHz-電子サイクロトロン波解析

    恩地拓己,出射浩,池添竜也,福山雅治,長谷川真,花田和明,江尻晶,小野雅之,福山淳

    第34回プラズマ・核融合学会 年会  2019年12月 

     詳細を見る

    開催年月日: 2019年12月

    記述言語:日本語   会議種別:口頭発表(一般)  

    開催地:大阪大学吹田キャンパス内コンベンションセンター   国名:日本国  

  • Second harmonic EC plasma ramp-up through production of energetic electrons on the QUEST spherical tokamak 国際会議

    Takumi Onchi, H. Idei, M. Hasegawa, K. Kuroda, R. Ikezoe, K. Hanada, A. Ejiri, T. Kariya, S. Kubo, T.I. Tsujimura, A. Fukuyama

    60th Annual Meeting of the APS Division of Plasma Physics  2019年11月 

     詳細を見る

    開催年月日: 2019年11月

    記述言語:英語   会議種別:口頭発表(一般)  

    国名:アメリカ合衆国  

  • High voltage electrical system of 8.56 GHz CW klystron for electron cyclotron heating on QUEST spherical tokamak 国際会議

    T. Onchi, H. Idei, K. Nakamura, T. Nagata, S. Kawasaki, R. Ashida, M. Fukuyama, M. Hasegawa, R. Ikezoe, A. Higashijima, K. Kuroda, Y. Nagashima, and K. Hanada

    30th Symposium on Fusion Technology (SOFT2018)  2018年9月 

     詳細を見る

    開催年月日: 2018年9月

    記述言語:英語   会議種別:口頭発表(一般)  

    国名:イタリア共和国  

  • 順列エントロピーと統計的複雑性を用いたプラズマ実験データの評価 招待

    恩地拓己

    プラズマ科学のフロンティア 2017 研究会  2017年8月 

     詳細を見る

    開催年月日: 2018年5月

    記述言語:日本語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

    開催地:核融合科学研究所   国名:日本国  

  • Electron cyclotron heating/current-drive system using high power tubes for QUEST spherical tokamak 国際会議

    TAKUMI ONCHI, H. IDEI, M.HASEGAWA, T. NAGATA, K. KURODA, K. HANADA, T. KARIYA, S. KUBO, T.I. TSUJIMURA, S. KOBAYASHI, NIFS, QUEST TEAM

    59th Annual Meeting of the APS Division of Plasma Physics  2017年10月 

     詳細を見る

    開催年月日: 2018年5月

    記述言語:英語   会議種別:口頭発表(一般)  

    国名:アメリカ合衆国  

  • Non-inductive current built-up by local electron cyclotron heating and current drive with a 28 GHz focused beam on QUEST 国際会議

    Takumi Onchi, Hiroshi Idei, Makoto Hasegawa, Hiroaki Ohwada, Hideki Zushi, Kazuaki Hanada, Tsuyoshi Kariya, Kishore Mishra, Taichi Shikama, Quest Team

    58th Annual Meeting of the APS Division of Plasma Physics  2016年11月 

     詳細を見る

    開催年月日: 2018年5月

    記述言語:英語   会議種別:口頭発表(一般)  

    国名:アメリカ合衆国  

  • Present status of current-drive system in QUEST spherical tokamak 招待 国際会議

    T. Onchi, H. Idei, K. Nakamura, M. Hasegawa, K. Yamasaki, O. Watanabe, K. Mishra, K. Kuroda, A. Kuzmin, H. Ohwada, A. Ejiri, H. Togashi, N. Matsumoto and K. Hanada

    AAPPS-DPP 2017  2017年9月 

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    開催年月日: 2018年5月

    記述言語:英語   会議種別:口頭発表(一般)  

    国名:中華人民共和国  

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MISC

  • 実験データの新しい解析方法 -順列エントロピーと統計的複雑性を用いた時系列データ評価-

    恩地 拓己

    プラズマ核融合学会学会誌   2017年4月

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    記述言語:日本語   掲載種別:記事・総説・解説・論説等(学術雑誌)  

    ノイズを含んだ時系列データを解析する際,順列エントロピーと統計的複雑性を求めることで従来よりも再現よくカオス性,ランダム性,周期性などの特性を区別して理解することが可能になった.近年では基礎プラズマ実験やトカマク・逆磁場ピンチなどの高温プラズマ実験で得られる時系列データへ適用した研究結果が発表され始めている.本稿では順列エントロピーと統計的複雑性を求める計算手法を示し,視覚的な理解に役立つC-H面を利用した特性評価方法について解説する.

所属学協会

  • 日本物理学会

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  • プラズマ核融合学会

  • 日本物理学会

  • アメリカ物理学会

  • アメリカ物理学会

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  • プラズマ核融合学会

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学術貢献活動

  • 学術論文等の審査

    役割:査読

    2024年

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    種別:査読等 

    外国語雑誌 査読論文数:1

  • 学術論文等の審査

    役割:査読

    2023年

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    種別:査読等 

    外国語雑誌 査読論文数:3

  • 学術論文等の審査

    役割:査読

    2022年

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    種別:査読等 

    外国語雑誌 査読論文数:5

  • 学術論文等の審査

    役割:査読

    2021年

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    種別:査読等 

    外国語雑誌 査読論文数:1

  • 学術論文等の審査

    役割:査読

    2020年

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    種別:査読等 

    外国語雑誌 査読論文数:1

  • 学術論文等の審査

    役割:査読

    2019年

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    種別:査読等 

    外国語雑誌 査読論文数:1

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共同研究・競争的資金等の研究課題

  • QUESTにおける新規ダイバータバイアスによって生成されるスクレイプオフ層(SOL)電流フィラメントと共鳴磁場摂動の最適化

    2023年4月 - 2024年3月

    共同研究

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    担当区分:研究代表者  資金種別:その他産学連携による資金

  • 先進炉での非誘導・炉心プラズマ立ち上げに向けた共鳴速度空間制御加熱とその機構解明

    研究課題/領域番号:21H01067  2023年 - 2025年

    日本学術振興会  科学研究費助成事業  基盤研究(B)

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    担当区分:研究分担者  資金種別:科研費

  • QUESTの高磁場化に向けたコイル電流モニター開発及びトロイダル磁場測定

    2022年4月 - 2023年3月

    共同研究

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    担当区分:研究代表者  資金種別:その他産学連携による資金

  • 先進炉での非誘導・炉心プラズマ立ち上げに向けた共鳴速度空間制御加熱とその機構解明

    研究課題/領域番号:23K20839  2021年4月 - 2026年3月

    科学研究費助成事業  基盤研究(B)

    出射 浩, 恩地 拓己

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    資金種別:科研費

    磁場閉じ込め核融合装置の中で核融合炉として有望な方式の1つがドーナツ形状したトカマク型である。ドーナツ断面が大きいコンパクトなトカマク炉は経済性が高くなるが、ドーナツ中心部が狭くなり、トカマク型で必要なドーナツ周回方向のプラズマ電流を流すための電磁石コイルを置くことが難しくなる。これまでに成功している高周波を用いたプラズマ電流立ち上げで、如何に高温プラズマへと成長させることができるかが鍵となる。電流立ち上げには高エネルギー電子の生成が有効であるが、本研究ではその過度な生成・成長を避け、全体として温度を上げるための手法開発、その機構解明をめざす。

    CiNii Research

  • 複数EC高調波による加熱電流駆動で生成される高エネルギー電子の制動放射計測

    研究課題/領域番号:21K03510  2021年 - 2023年

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    恩地 拓己

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    担当区分:研究代表者  資金種別:科研費

    トロイダル磁場の勾配が強い球状トカマクでは,加熱高周波を特定帯域内で選択することで複数の電子サイクロトロン(Electron Cyclotron, EC)高調波共鳴層がプラズマ閉じ込め領域に共存する状態を作り出せる.電子が数十keVのエネルギーを持つ場合,斜め伝播するEC波は電流駆動方向に動く電子に強く共鳴する.この共鳴条件の対称性の破れにより,電流駆動方向に動く電子は選択的に加熱され,正味の電流が流れる.本研究では制動放射硬X線を二次元計測して高エネルギー電子の空間分布を観測し,共鳴条件の対称性がどのように破れているかを実験的に調査する.

    CiNii Research

  • QUESTの高トロイダル磁場化検討

    2019年4月 - 2022年3月

    共同研究

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    担当区分:研究代表者  資金種別:その他産学連携による資金

  • GAMMA10/PDXダイバータ上流領域におけるドップラー分光を用いた磁力線方向フロー計測

    2016年4月 - 2018年3月

    共同研究

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    担当区分:研究代表者  資金種別:その他産学連携による資金

  • 定常化球状トカマク開磁気面領域における能動的放射損失が誘起する熱流変動

    研究課題/領域番号:15K17800  2015年 - 2016年

    科学研究費助成事業  若手研究(B)

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    担当区分:研究代表者  資金種別:科研費

  • 軟X線計測による低アスペクト比RFPプラズマの内部磁場構造測定

    研究課題/領域番号:08J10258  2008年 - 2009年

    日本学術振興会  科学研究費助成事業  特別研究員奨励費

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    担当区分:研究代表者  資金種別:科研費

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担当授業科目

  • プラズマ理工学演習

    2023年10月 - 2024年3月   後期

  • プラズマ理工学演習

    2022年10月 - 2023年3月   後期

  • プラズマ理工学演習

    2021年10月 - 2022年3月   後期