Updated on 2024/12/24

Information

 

写真a

 
IDO TAKESHI
 
Organization
Research Institute for Applied Mechanics Advanced Fusion Research Center Professor
Interdisciplinary Graduate School of Engineering Sciences Department of Interdisciplinary Engineering Sciences(Concurrent)
Title
Professor
Contact information
メールアドレス
Tel
0925837695
Profile
・磁場閉じ込めプラズマ中に発生する不安定性、乱流及び電場形成に関する実験研究 ・重イオンビームを用いた計測器の開発
External link

Research Areas

  • Energy Engineering / Nuclear fusion

Degree

  • Ph.D.

Research History

  • Kyushu University Research Institute for Applied Mechanics Professor

    2019.10 - Present

      More details

    Country:Japan

    researchmap

  • 2000年4月―2019年9月 核融合科学研究所

Education

  • Nagoya University

    - 2000

      More details

    Country: Japan

    researchmap

  • Nagoya University   Graduate School, Division of Engineering

    - 2000

      More details

  • Osaka University   Faculty of Science

    - 1994

      More details

  • Osaka University   School of Science

    - 1994

      More details

    Country: Japan

    researchmap

Research Interests・Research Keywords

  • Research theme:プラズマ物理学

    Keyword:プラズマ物理学

    Research period: 2024

  • Research theme:Plasma physics

    Keyword:Plasma physics

    Research period: 2024

  • Research theme:Development of Heavy Ion Beam Probes for QUEST spherical tokamak and PLATO tokamak

    Keyword:Heavy ion beam probe, HIBP, turbulence, tokamak, plasma confinement

    Research period: 2019.10

  • Research theme:Investigation of the physical mechanism of formation of the electric potential profiles and turbulent transport in the magnetically confined plasmas

    Keyword:Magnetically confined plasma, electric potential profile, Heavy Ion Beam Probe, turbulence, nuclear fusion

    Research period: 2004.4

  • Research theme:Development of Heavy Ion Beam Probe on the Large Helical Device

    Keyword:Heavy Ion Beam Probe (HIBP), Electric Potential Measurement

    Research period: 2000.4

  • Research theme:Investigation of spatio-temporal evolution of electric potential in JFT-2Mトカマク

    Keyword:magnetically confined plasma, L-H transition, electric field, turbulence, turubulent transport, Heavy Ion Beam Probe (HIBP)

    Research period: 1999.4 - 2006.3

  • Research theme:Development of Heavy Ion Beam Probe on JFT-2M tokamak

    Keyword:Heavy Ion Beam Probe (HIBP)

    Research period: 1997.10 - 2004.3

Awards

  • 自然科学研究機構若手研究者賞

    2012.6   自然科学研究機構  

  • 第15回技術進歩賞

    2010.11   プラズマ・核融合学会   大型ヘリカル装置における重イオンビームプローブの開発

Papers

  • Development of a heavy ion beam probe diagnostic for HL-2A tokamak Reviewed International journal

    H.R. Fan, L.T. Gao, A.D. Liu, G. Zhuang, T. Ido, M. Xu, J.C. Huang, J. Zhang, C.Q. Feng, C. Zhou, H. Liu, L. Nie, Y.X. Liu, B.Z. Fu, J.Q. Li and W.D. Liu

    Journal of Instrumentation   18 ( 1 )   2023.1

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/1748-0221/18/01/P01008

  • Conceptual design of a heavy ion beam probe for the QUEST spherical tokamak

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

    Review of Scientific Instruments   2022.11

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/5.0101770

  • Geodesic acoustic modes in magnetic confinement devices Invited Reviewed International journal

    Conway, G.D., Smolyakov, A.I., Ido, T.

    Nuclear Fusion   62 ( 1 )   013001-1 - 013001-149   2022.1

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: https://doi.org/10.1088/1741-4326/ac0dd1

  • Conceptual design of heavy ion beam probes on the PLATO tokamak Reviewed International journal

    T. Ido, A. Fujisawa, K. Takemura, T.-K. Kobayashi, D. Nishimura, N. Kasuya, A. Fukuyama, C. Moon, K. Yamasaki, S. Inagaki, Y. Nagashima, and T. Yamada

    Review of Scientific Instruments   92   053553   2021.5

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/5.0041814

    Other Link: https://doi.org/10.1063/5.0041814

  • Observation of subcritical geodesic acoustic mode excitation in the large helical device Reviewed International journal

    Nuclear Fusion   57   072009   2017.4

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/1741-4326/aa665a

  • Strong Destabilization of Stable Modes with a Half-Frequency Associated with Chirping Geodesic Acoustic Modes in the Large Helical Device Reviewed International journal

    T. Ido, K. Itoh, M. Osakabe, M. Lesur, A. Shimizu, K. Ogawa, K. Toi, M. Nishiura, S. Kato, M. Sasaki, K. Ida, S. Inagaki, S.-I. Itoh, the LHD Experiment Group

    Physical Review Letters   116   015002   2016.1

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1103/PhysRevLett.116.015002

  • Electrostatic Potential Measurement by Using 6-MeV Heavy Ion Beam Probe on LHD Invited Reviewed International journal

    Takeshi IDO, Akihiro SHIMIZU, Masaki NISHIURA, Shinji KATO, Haruhisa NAKANO, Akimitsu NISHIZAWA, Yasuji HAMADA, Mitsuhiro YOKOTA, Kiwamu TSUKADA, Hideki OGAWA, Tomoyuki INOUE, Katsumi IDA, Mikiro YOSHINUMA, Sadayoshi MURAKAMI, Kenji TANAKA, Kazumichi NARIHARA, Ichihiro YAMADA, Kazuo KAWAHATA, Naoki TAMURA and the LHD Experimental Group

    Plasma and Fusion Research   3   031   2008.4

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1585/pfr.3.031

    Other Link: http://www.jspf.or.jp/PFR/PFR_articles/pfr2008/pfr2008_03-031.html

  • Geodesic–acoustic-mode in JFT-2M tokamak plasmas Invited Reviewed International journal

    48   S41   2006.3

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    The characteristics of geodesic–acoustic-mode (GAM) are investigated through direct and simultaneous measurement of electrostatic and density fluctuations with a heavy ion beam probe. The amplitude of the GAM changes in relation to the radial position; it is small near the separatrix, reaches a local maximum at 3 cm inside the separatrix and then decreases again to 5 cm inside the separatrix. The frequency is constant in the range, though the predicted GAM frequency varies according to the temperature gradient. The correlation length is about 6 cm and comparable to the structure of the amplitude of the GAM. The results indicate the GAM has a radial structure which reflects the local condition at about 3 m inside the separatrix. The phase relation between the GAM oscillation indicates that the GAM is a radial propagating wave.
    The interaction between the GAM and the ambient density fluctuation is shown by the high coherence between the GAM oscillation and the temporal behaviour of the ambient density fluctuation. Moreover, the phase relation between the electric field fluctuation of the GAM (E˜r,GAM) and the amplitude of the density fluctuation indicates that the modulation of the ambient density fluctuation delays the E˜r,GAM. The causality between the GAM and the modulation of the density fluctuation is revealed.

    DOI: 10.1088/0741-3335/48/4/S04

    Other Link: https://iopscience.iop.org/article/10.1088/0741-3335/48/4/S04

  • Observation of the interaction between the geodesic acoustic mode and ambient fluctuation in the JFT-2M tokamak Reviewed International journal

    46 ( 5 )   512   2006.3

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    The electrostatic and density fluctuation are measured simultaneously with a heavy ion beam probe. The electrostatic fluctuation with the geodesic acoustic mode (GAM) frequency is observed in L-mode plasmas and not in H-mode plasmas. The poloidal and radial structure is consistent with the GAM. So the fluctuation is concluded to be the GAM. The amplitude of the GAM changes in the radial direction; it is small near the separatrix, has a maximum at 3 cm inside the separatrix and decreases again to 5 cm inside the separatrix. The GAM and the temporal behaviour of the ambient density fluctuation show a significant coherence, and the phase of modulation of the ambient density fluctuation tends to delay the potential oscillation of the GAM. It is clearly verified that the GAM affects ambient fluctuation and also the local particle transport through modulation of the amplitude of the ambient fluctuation.

    DOI: 10.1088/0029-5515/46/5/003

    Other Link: https://iopscience.iop.org/article/10.1088/0029-5515/46/5/003

  • Overview of Large Helical Device experiments of basic plasma physics for solving crucial issues in reaching burning plasma conditions

    Ida, K; Yoshinuma, M; Kobayashi, M; Kobayashi, T; Kenmochi, N; Nespoli, F; Magee, RM; Warmer, F; Dinklage, A; Matsuyama, A; Sakamoto, R; Nasu, T; Tokuzawa, T; Kinoshita, T; Tanaka, K; Tamura, N; Nagaoka, K; Nishiura, M; Takemura, Y; Ogawa, K; Motojima, G; Oishi, T; Morishita, Y; Varela, J; Hayashi, WHJ; Markl, M; Bouvain, H; Liang, Y; Leconte, M; Moseev, D; Moiseenko, VE; Albert, CG; Allfrey, I; Alonso, A; Arellano, FJ; Ashikawa, N; Azegami, A; Bardoczi, L; Van Berkel, M; Beurskens, M; Binderbaue, MW; Bortolon, A; Brezinsek, S; Bussiahn, R; Cappa, A; Carralero, D; Chan, IC; Cheng, J; Dai, X; Den Hartog, DJ; Dhard, CP; Ding, F; Ejiri, A; Ertmer, S; Fornal, T; Fujita, K; Fujiwara, Y; Funaba, H; Garcia, L; Garcia-Regana, JM; Garcia-Cortés, I; Garkusha, IE; Gates, DA; Ghai, Y; Gilson, EP; Gota, H; Goto, M; Green, EM; Haak, V; Hamaguchi, S; Hanada, K; Hara, H; Hartmann, D; Hayashi, Y; Henning, T; Hidalgo, C; Hillairet, J; Hutton, R; Ido, T; Igami, H; Ikeda, K; Inagaki, S; Ishizawa, A; Ito, S; Isobe, M; Isobe, Y; Ivkovic, M; Jiang, Z; Jo, J; Kamio, S; Kasahara, H; Kato, D; Katoh, Y; Kawachi, Y; Kawamoto, Y; Kawamura, G; Kawate, T; Kazakov, YO; Klumper, V; Knieps, A; Ko, WH; Kobayashi, S; Koike, F; Kovtun, YV; Kubkowska, M; Kubo, S; Lam, SSH; Langenberg, A; Laqua, H; Lazerson, S; Lestz, J; Li, B; Liao, L; Lin, Z; Lunsford, R; Masuzaki, S; Matsuura, H; McCarthy, KJ; Medina-Roque, D; Mitarai, O; Mollen, A; Moon, C; Mori, Y; Morisaki, T; Morita, S; Mukai, K; Murakami, I; Murakami, S; Murase, T; Muscatello, CM; Nagasaki, K; Naujoks, D; Nakano, H; Nakata, M; Narushima, Y; Nagy, A; Nicolau, JH; Nishizawa, T; Nishimoto, S; Nuga, H; Nunami, M; Ochoukov, R; Ohdachi, S; Ongena, J; Osakabe, M; Pablant, NA; Panadero, N; Peterson, B; Villén, JD; Romazanov, J; Rosato, J; Rud, M; Sakakibara, S; Sakaue, HA; Sakai, H; Sakon, I; Salewski, M; Sangaroon, S; Sereda, S; Stange, T; Saito, K; Satake, S; Seki, R; Seki, T; Sharapov, S; Shimizu, A; Shimozuma, T; Shivam, G; Shoji, M; Spong, DA; Sugama, H; Sun, Z; Suzuki, C; Suzuki, Y; Tajima, T; Takada, E; Takahashi, H; Toi, K; Tsuchibushi, Y; Tsujii, N; Tsumori, K; Tsujimurai, TI; Ueno, G; Uehara, H; Velasco, JL; Wang, E; Watanabe, KY; Wauter, T; Wenzel, U; Yajima, M; Yamada, H; Yamada, I; Yanagihara, K; Yamaguchi, H; Yanai, R; Yasuhara, R; Yokoyama, M; Yoshimura, Y; Zarnstorff, M; Zhao, M; Zhong, GQ; Zhou, Q; Ziaei, S

    NUCLEAR FUSION   64 ( 11 )   2024.11   ISSN:0029-5515 eISSN:1741-4326

     More details

    Publisher:Nuclear Fusion  

    Recently, experiments on basic plasma physics issues for solving future problems in fusion energy have been performed on a Large Helical Device. There are several problems to be solved in future devices for fusion energy. Emerging issues in burning plasma are: alpha-channeling (ion heating by alpha particles), turbulence and transport in electron dominant heating helium ash exhaust, reduction of the divertor heat load. To solve these problems, understanding the basic plasma physics of (1) wave-particle interaction through (inverse) Landau damping, (2) characteristics of electron-scale (high-k) turbulence, (3) ion mixing and the isotope effect, and (4) turbulence spreading and detachment, is necessary. This overview discusses the experimental studies on these issues and turbulent transport in multi-ion plasma and other issues in the appendix.

    DOI: 10.1088/1741-4326/ad3a7a

    Web of Science

    Scopus

  • 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 )   2024.11   ISSN:0741-3335 eISSN:1361-6587

     More details

    Publisher: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 )   2024.10   ISSN:0029-5515 eISSN:1741-4326

     More details

    Publisher: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 )   2024.6   ISSN:0029-5515 eISSN:1741-4326

     More details

    Publisher: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

    Junyao Zhou, Hanada Kazuaki, Kuroda Kengoh, Onchi Takumi, Idei Hiroshi, Ikezoe Ryuya, Hasegawa Makoto, Nagashima Yoshihiko, Ido Takeshi, Kinoshita Toshiki

    Evergreen   11 ( 2 )   555 - 562   2024.6   ISSN:21890420 eISSN:24325953

     More details

    Language:English   Publisher:Transdisciplinary Research and Education Center for Green Technologies, Kyushu University  

    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

    CiNii Research

  • Core density profile control by energetic ion anisotropy in LHD

    Nishiura, M; Shimizu, A; Ido, T; Satake, S; Yoshinuma, M; Yanai, R; Nunami, M; Yamaguchi, H; Nuga, H; Seki, R; Fujita, K; Salewski, M

    PHYSICS OF PLASMAS   31 ( 6 )   2024.6   ISSN:1070-664X eISSN:1089-7674

     More details

    Publisher:Physics of Plasmas  

    Electron and impurity ion density profiles have been controlled by using tangential and perpendicular neutral beams for plasma heating in a stellarator/heliotron for the first time. Reduced anisotropy of stored energy for energetic ion En⊥/Enǁ has resulted in an inward electron and impurity transport, forming a core electron density peaking. Increased anisotropy leads to a flat or hollowed electron density profile with an impurity exhaust in a core region [Yoshinuma et al., Nucl. Fusion 49, 062002 (2009)]. A high confinement state of particles in LHD has yet to be achieved, except for a temporal state of an electron density peaking created by a pellet injection. As a pioneering and crucial research result, the operation of energetic ion anisotropy by neutral beams has newly demonstrated that the direction of the radial transport of bulk and impurity ions can be controlled. At the same time, the overall plasma performance rises in neutron flux and stored energy. On the other hand, the increase in the anisotropy flattens the density profile. This new finding holds promise for a control knob of nuclear fusion reactors to enhance fusion power output.

    DOI: 10.1063/5.0201440

    Web of Science

    Scopus

  • Identification of nonlinear effects of background asymmetry on solitary oscillations in a cylindrical plasma

    Kobayashi, T; Fujisawa, A; Nagashima, Y; Moon, C; Yamasaki, K; Nishimura, D; Inagaki, S; Shimizu, A; Tokuzawa, T; Ido, T

    SCIENTIFIC REPORTS   14 ( 1 )   12175   2024.5   ISSN:2045-2322

     More details

    Language:English   Publisher:Scientific Reports  

    A symmetry-breaking in rotational spatial pattern of quasi-periodic solitary oscillations is revealed with tomography measurement of plasma emission, simultaneously with background asymmetry in stationary plasma structure. Although the oscillatory pattern deformation is a natural course in the presence of asymmetry, elaborate analyses identify existence unfeatured nonlinear effects of the background asymmetry, i.e., its nonlinear couplings with harmonic modes of rotational symmetry, to produce non-harmonic mode to break the symmetry and cause the oscillatory pattern to be chaotic. The findings suggest the unrecognized fundamental process for plasmas to be turbulent.

    DOI: 10.1038/s41598-024-62969-1

    Web of Science

    Scopus

    PubMed

  • 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 )   2024.4   ISSN:0741-3335 eISSN:1361-6587

     More details

    Publisher: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

  • A Method to Analyze Plasma Images Using Modified Fourier-Bessel Functions

    NISHIMURA Yuki, FUJISAWA Akihide, NAGASHIMA Yoshihiko, MOON Chanho, NISHIZAWA Takashi, KOBAYASHI Tatsuya, SHIMIZU Akihiro, TOKUZAWA Tokihiko, IDO Takeshi, NISHIMURA Daiki, KOBAYASHI Taiki

    Plasma and Fusion Research   19 ( 0 )   1201014 - 1201014   2024.3   ISSN:1880-6821 eISSN:18806821

     More details

    Language:English   Publisher:The Japan Society of Plasma Science and Nuclear Fusion Research  

    <p>A new method is proposed to analyze plasma image of tomography using modified Fourier-Bessel Functions (FBF) instead of the original FBF analysis. The application of the method to an assumed plasma image shows that the difference between the original and the fitting image is improved considerably to that of FBF, owing to giving a better fitting inside the plasma and eliminating the ghost values outside the plasma, without any disadvantages in analysis of plasma structures and patterns.</p>

    DOI: 10.1585/pfr.19.1201014

    Web of Science

    Scopus

    CiNii Research

  • 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 )   2024.1   ISSN:0029-5515 eISSN:1741-4326

     More details

    Publisher: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

  • 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 )   2023.10   ISSN:0029-5515 eISSN:1741-4326

     More details

    Publisher: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

  • Rotational movement analysis based on Fourier-rectangular function transform for cylindrical plasma

    Nishimura, D; Fujisawa, A; Yamasaki, K; Nagashima, Y; Moon, C; Nishizawa, T; Kobayashi, TK; Kobayashi, T; Shimizu, A; Tokuzawa, T; Ido, T

    JOURNAL OF APPLIED PHYSICS   134 ( 11 )   2023.9   ISSN:0021-8979 eISSN:1089-7550

     More details

    Publisher:Journal of Applied Physics  

    This article presents a method to estimate the rotational velocity of a cylindrical plasma from its two-dimensional images by an extended use of the Fourier-rectangular function transform, which was proposed to analyze the structure and dynamics of a cylindrical plasma [K. Yamasaki e t a l ., J. Appl. Phys. 126 , 043304 (2019)]. The proposed method is applied to tomography images of plasmas produced in a linear cylindrical device and succeeds in obtaining the radial distribution of rotational velocity and its fluctuations, providing an interesting finding, that is, the existence of flow modulation associated with m = 1 mode fluctuations.

    DOI: 10.1063/5.0165318

    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 )   2023.9   ISSN:0029-5515 eISSN:1741-4326

     More details

    Publisher: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 )   2023.9   ISSN:00295515 eISSN:17414326

     More details

    Language:English  

    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

  • 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   2023.7   ISSN:0920-3796 eISSN:1873-7196

     More details

    Publisher: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

    Web of Science

    Scopus

  • Sudden Change Events of Plasma Current during Electron-Cyclotron Current Start-Up on the QUESTB Spherical Tokamak Reviewed International journal

    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   402066   2023.6

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1585/pfr.18.2402066

  • 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   2023.6   ISSN:0920-3796 eISSN:1873-7196

     More details

    Publisher: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

    Web of Science

    Scopus

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

    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 )   2023.5   ISSN:1009-0630 eISSN:2058-6272

     More details

    Publisher: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.

    DOI: 10.1088/2058-6272/acafc2

    Web of Science

    Scopus

  • Design Study of a Line Integrated Thomson Scattering System for TST-2 Spherical Tokamak Device

    EJIRI Akira, LIN Yu-Ting, JANG Seowon, PENG Yi, SHINOHARA Kouji, IDO Takeshi, KONO Kaori, NAGASHIMA Yoshihiko

    Plasma and Fusion Research   18 ( 0 )   2402025 - 2402025   2023.4   ISSN:1880-6821 eISSN:18806821

     More details

    Language:English   Publisher:The Japan Society of Plasma Science and Nuclear Fusion Research  

    <p>A design study of a line integrated Thomson scattering (TS) system with a complete backscattering configuration has been performed to clarify practical problems. Installation on the TST-2 spherical tokamak was assumed, and an optical system design with ready-made components, are adopted. Some practical aspects, such as aberration, masking effect of the laser combining mirror, misalignment are investigated by ray tracing calculations. The performance of density profile reconstruction was also investigated. It was found that a tangential-multi-chord measurement configuration on the midplane shows a good effective localization, and error enhancement in the reconstruction is small. In addition, the efficiency of the system is about an order of magnitude larger than the present conventional TS system in TST-2. The attractiveness of the line integrated TS measurements was demonstrated.</p>

    DOI: 10.1585/pfr.18.2402025

    Web of Science

    Scopus

    CiNii Research

  • QUEST Database for Tokamak Big Data Reviewed International journal

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

    18   1305048   2023.4

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1585/pfr.18.1305048

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

    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   2023.4   ISSN:0920-3796 eISSN:1873-7196

     More details

    Publisher: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.

    DOI: 10.1016/j.fusengdes.2023.113479

    Web of Science

    Scopus

  • Quaternion Analysis of Transient Phenomena of Motor-Generator Reviewed International journal

    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   18   2405035   2023.3

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1585/pfr.18.2405035

  • A Proposal to Evaluate Electron Temperature and Electron Density Fluctuations Using Dual Wavelength Emission Intensity Tomography in a Linear Plasma

    Yoshihiko Nagashima, Akihide Fujisawa, Kotaro Yamasaki, Shigeru Inagaki, Chanho Moon, Fumiyoshi Kin, Yuichi Kawachi, Hiroyuki Arakawa, Takuma Yamada, Tatsuya Kobayashi, Naohiro Kasuya, Yusuke Kosuga, Makoto Sasaki, Takeshi Ido

    Journal of the Physical Society of Japan   92 ( 3 )   2023.3

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.7566/jpsj.92.033501

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

    KONO Kaori, IDO Takeshi, EJIRI Akira, HANADA Kazuaki, YUE Qilin, HASEGAWA Makoto, PENG Yi, SAKAI Seiya, IKEZOE Ryuya, IDEI Hiroshi, KAWASAKI Syoji, KURODA Kengoh, ONCHI Takumi, NAGASHIMA Yoshihiko, JANG Seowon

    Plasma and Fusion Research   18 ( 0 )   1405012 - 1405012   2023.2   ISSN:1880-6821 eISSN:18806821

     More details

    Language:English   Publisher:The Japan Society of Plasma Science and Nuclear Fusion Research  

    <p>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.</p>

    DOI: 10.1585/pfr.18.1405012

    Web of Science

    Scopus

    CiNii Research

  • Hydrogen isotope effect on self-organized electron internal transport barrier criticality and role of radial electric field in toroidal plasmas

    Scientific Reports   12 ( 1 )   2022.12

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1038/s41598-022-09526-w

  • Behavior of geodesic acoustic mode and limit-cycle oscillation approaching L-H transition in JFT-2M tokamak

    Kobayashi, T; Sasaki, M; Ido, T; Kamiya, K; Miura, Y; Ida, K; Itoh, K

    PLASMA PHYSICS AND CONTROLLED FUSION   64 ( 11 )   2022.11   ISSN:0741-3335 eISSN:1361-6587

     More details

    Publisher:Plasma Physics and Controlled Fusion  

    In this paper, a phenomenology of competing behavior between the geodesic acoustic mode (GAM) and the limit-cycle oscillation (LCO) is presented. Before the LCO occurs, the GAM can grow to the observable amplitude via the turbulent Reynolds stress force. Approaching the L-H transition, the LCO is excited and the GAM decays. In the LCO phase, the GAM driving force is possibly suppressed by the nonlocal turbulence amplitude modulation by the LCO.

    DOI: 10.1088/1361-6587/ac9333

    Web of Science

    Scopus

  • 3D metal powder additive manufacturing phased array antenna for multichannel Doppler reflectometer

    T. Tokuzawa, T. Nasu, S. Inagaki, C. Moon, T. Ido, H. Idei, A. Ejiri, R. Imazawa, M. Yoshida, N. Oyama, K. Tanaka, K. Ida

    Review of Scientific Instruments   2022.11

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/5.0101723

  • Design Considerations for the Implementation of a High-Field-Side Transient CHI System on QUEST Invited Reviewed International journal

    R. Raman, K. Kuroda, K. Hanada, M. Ono, M. Hasegawa, T. Onchi, R. Ikezoe, H. Idei, T. Ido, J.A. Rogers

    Journal of Fusion Energy   4171 - 4176   2022.11

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1109/TPS.2022.3193069

  • Improvements to the High-Field-Side Transient CHI System on QUEST Reviewed International journal

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

    Journal of Fusion Energy   41 ( 2 )   25   2022.11

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1007/s10894-022-00338-4

  • Adaptive Capon beamforming for lensless electron cyclotron emission imaging with high spatial resolution Reviewed International journal

    H. Idei, M. Fukuyama, S. Sakai, K. Mishra, K. Nishimura, R. Ikezoe, T. Onchi, T. Ido, K. Hanada

    Review of Scientific Instruments   20   103531   2022.10

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/5.0101632

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

    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   113199 - 113199   2022.7

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.fusengdes.2022.113199

  • Geodesic acoustic modes in magnetic confinement devices

    G.D. Conway, A.I. Smolyakov, T. Ido

    Nuclear Fusion   62 ( 1 )   013001 - 013001   2022.1   ISSN:0029-5515 eISSN:1741-4326

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:IOP Publishing  

    Abstract

    Geodesic acoustic modes (GAMs) are ubiquitous oscillatory flow phenomena observed in toroidal magnetic confinement fusion plasmas, such as tokamaks and stellarators. They are recognized as the non-stationary branch of the turbulence driven zonal flows which play a critical regulatory role in cross-field turbulent transport. GAMs are supported by the plasma compressibility due to magnetic geodesic curvature—an intrinsic feature of any toroidal confinement device. GAMs impact the plasma confinement via velocity shearing of turbulent eddies, modulation of transport, and by providing additional routes for energy dissipation. GAMs can also be driven by energetic particles (so-called EGAMs) or even pumped by a variety of other mechanisms, both internal and external to the plasma, opening-up possibilities for plasma diagnosis and turbulence control. In recent years there have been major advances in all areas of GAM research: measurements, theory, and numerical simulations. This review assesses the status of these developments and the progress made towards a unified understanding of the GAM behaviour and its role in plasma confinement. The review begins with tutorial-like reviews of the basic concepts and theory, followed by a series of topic orientated sections covering different aspects of the GAM. The approach adopted here is to present and contrast experimental observations alongside the predictions from theory and numerical simulations. The review concludes with a comprehensive summary of the field, highlighting outstanding issues and prospects for future developments.

    DOI: 10.1088/1741-4326/ac0dd1

    Web of Science

    Scopus

    researchmap

    Other Link: https://iopscience.iop.org/article/10.1088/1741-4326/ac0dd1/pdf

  • The first observation of 4D tomography measurement of plasma structures and fluctuations Reviewed

    Chanho Moon, Kotaro Yamasaki, Yoshihiko Nagashima, Shigeru Inagaki, Takeshi Ido, Takuma Yamada, Naohiro Kasuya, Yusuke Kosuga, Makoto Sasaki, Yuichi Kawachi, Daiki Nishimura, Taiki Kobayashi, Akihide Fujisawa

    Scientific Reports   11 ( 1 )   2021.12

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1038/s41598-021-83191-3

  • Conceptual design of a heavy ion beam probe diagnostic for HL-2M tokamak Reviewed

    H.R. Fan, T. Ido, A.D. Liu, Min Xu, Z.Y. Liu, Ge Zhuang, L.J. Cai, J.X. Li, L.T. Gao, Chu Zhou, Lin Nie, J.Q. Li, W.D. Liu

    Fusion Engineering and Design   173   112845 - 112845   2021.12

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.fusengdes.2021.112845

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

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

    Nuclear Materials and Energy   26   2021.3

     More details

    Language:Others  

    DOI: 10.1016/j.nme.2020.100872

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

    N. Yoneda, T. Shikama, K. Hanada, S. Mori, T. 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, R. Ikezoe, M. Hasegawa, A. Higashijima, T. Nagata, S. Shimabukuro

    Nuclear Materials and Energy   26   2021.3

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.nme.2021.100905

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

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

    Physics of Plasmas   28 ( 2 )   2021.2

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/5.0031357

  • The systematic investigation of energetic-particle-driven geodesic acoustic mode channeling using MEGA code Reviewed

    Hao Wang, Yasushi Todo, Masaki Osakabe, Takeshi Ido, Yasuhiro Suzuki

    Nuclear Fusion   60 ( 11 )   2020.11

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/1741-4326/ab8a04

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

    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 )   2020.9

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.3390/atoms8030044

  • Comparison between Tomography and Langmuir Probe Data in PANTA Reviewed

    Yoshihiko Nagashima, Akihide Fujisawa, Kotaro Yamasaki, Shigeru Inagaki, Chanho Moon, Fumiyoshi Kin, Yuichi Kawachi, Hiroyuki Arakawa, Takuma Yamada, Tatsuya Kobayashi, Naohiro Kasuya, Yusuke Kosuga, Makoto Sasaki, Takeshi Ido

    Journal of the Physical Society of Japan   89 ( 9 )   093501 - 093501   2020.9

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.7566/jpsj.89.093501

  • Erratum: Impact of a resonant magnetic perturbation field on impurity radiation, divertor footprint, and core plasma transport in attached and detached plasmas in the Large Helical Device (Nuclear Fusion (2019) 59 (096009) DOI: 10.1088/1741-4326/ab26e6) Reviewed

    M. Kobayashi, R. Seki, S. Masuzaki, S. Morita, H. M. Zhang, Y. Narushima, H. Tanaka, K. Tanaka, T. Tokuzawa, M. Yokoyama, T. Ido, I. Yamada

    Nuclear Fusion   59 ( 10 )   2019.8

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/1741-4326/ab3a13

  • Simulation of energetic particle driven geodesic acoustic modes and the energy channeling in the Large Helical Device plasmas Reviewed

    Hao Wang, Yasushi Todo, Masaki Oasakabe, Takeshi Ido, Yasuhiro Suzuki

    Nuclear Fusion   59 ( 9 )   2019.8

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/1741-4326/ab26e5

  • Core plasma confinement during detachment transition with RMP application in LHD Reviewed

    M. Kobayashi, S. Masuzaki, K. Tanaka, T. Tokuzawa, M. Yokoyama, Y. Narushima, I. Yamada, T. Ido, R. Seki

    Nuclear Materials and Energy   17   137 - 141   2018.12

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.nme.2018.10.003

  • Realization of high T <inf>i</inf> plasmas and confinement characteristics of ITB plasmas in the LHD deuterium experiments Reviewed

    H. Takahashi, K. Nagaoka, K. Mukai, M. Yokoyama, S. Murakami, S. Ohdachi, T. Bando, Y. Narushima, H. Nakano, M. Osakabe, K. Ida, M. Yoshinuma, R. Seki, H. Yamaguchi, K. Tanaka, M. Nakata, F. Warmer, T. Oishi, M. Goto, S. Morita, T. I. Tsujimura, S. Kubo, T. Kobayashi, I. Yamada, C. Suzuki, M. Emoto, T. Ido, A. Shimizu, T. Tokuzawa, K. Nagasaki, T. Morisaki, Y. Takeiri

    Nuclear Fusion   58 ( 10 )   2018.8

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/1741-4326/aad87e

  • Energy confinement of hydrogen and deuterium electron-root plasmas in the Large Helical Device Reviewed

    Felix Warmer, H. Takahashi, K. Tanaka, Y. Yoshimura, C. D. Beidler, B. Peterson, H. Igami, T. Ido, R. Seki, M. Nakata, M. Yokoyama, T. Akiyama, H. Funaba, K. Ida, S. Kubo, A. Shimizu, T. Shimozuma, T. Tokuzawa, T. I. Tsujimura, H. Yamada, I. Yamada, R. Yasuhara, M. Yoshinuma, S. Yoshimura, T. Morisaki, M. Osakabe

    Nuclear Fusion   58 ( 10 )   2018.8

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/1741-4326/aad611

  • Abrupt excitation of energetic-particle-driven geodesic acoustic mode in the large helical device Reviewed International journal

    Takeshi Ido

    AIP Conference Proceedings   1993   020002   2018.8

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    DOI: 10.1063/1.5048712

  • Excitation of helically-trapped-energetic-ion driven resistive interchange modes with intense deuterium beam injection and enhanced effect on beam ions/bulk plasmas of LHD Reviewed

    T. Bando, S. Ohdachi, M. Isobe, Y. Suzuki, K. Toi, K. Nagaoka, H. Takahashi, R. Seki, X. D. Du, K. Ogawa, T. Ido, A. Shimizu, T. Ozaki

    Nuclear Fusion   58 ( 8 )   2018.6

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/1741-4326/aac699

  • Quantification of Turbulent Driving Forces for the Geodesic Acoustic Mode in the JFT-2M Tokamak Reviewed

    T. Kobayashi, M. Sasaki, T. Ido, K. Kamiya, Y. Miura, Y. Nagashima, K. Ida, S. Inagaki, A. Fujisawa, S. I. Itoh, K. Itoh

    Physical Review Letters   120 ( 4 )   2018.1

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1103/PhysRevLett.120.045002

  • Turbulent transport reduction induced by transition on radial electric field shear and curvature through amplitude and cross-phase in torus plasma Reviewed

    T. Kobayashi, K. Itoh, T. Ido, K. Kamiya, S. I. Itoh, Y. Miura, Y. Nagashima, A. Fujisawa, S. Inagaki, K. Ida

    Scientific Reports   7 ( 1 )   2017.12

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1038/s41598-017-14821-y

  • Extended capability of the integrated transport analysis suite, TASK3D-a, for LHD experiment Reviewed

    M. Yokoyama, R. Seki, C. Suzuki, M. Sato, M. Emoto, S. Murakami, M. Osakabe, T. Ii Tsujimura, Y. Yoshimura, T. Ido, K. Ogawa, S. Satake, Y. Suzuki, T. Goto, K. Ida, N. Pablant, D. Gates, F. Warmer, P. Vincenzi

    Nuclear Fusion   57 ( 12 )   2017.9

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/1741-4326/aa800a

  • Extension of the operational regime of the LHD towards a deuterium experiment Reviewed

    Nuclear Fusion   57 ( 10 )   2017.8

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/1741-4326/aa7fc2

  • Extension of operational regime in high-temperature plasmas and effect of ECRH on ion thermal transport in the LHD Reviewed

    H. Takahashi, K. Nagaoka, S. Murakami, M. Osakabe, H. Nakano, K. Ida, T. I. Tsujimura, S. Kubo, T. Kobayashi, K. Tanaka, R. Seki, Y. Takeiri, M. Yokoyama, S. Maeta, M. Nakata, M. Yoshinuma, I. Yamada, R. Yasuhara, T. Ido, A. Shimizu, H. Tsuchiya, T. Tokuzawa, M. Goto, T. Oishi, S. Morita, C. Suzuki, M. Emoto, K. Tsumori, K. Ikeda, M. Kisaki, T. Shimozuma, Y. Yoshimura, H. Igami, R. Makino, T. Seki, H. Kasahara, K. Saito, S. Kamio, K. Nagasaki, T. Mutoh, O. Kaneko, T. Morisaki

    Nuclear Fusion   57 ( 8 )   2017.7

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/1741-4326/aa754b

  • Model validation for radial electric field excitation during L-H transition in JFT-2M tokamak Reviewed

    T. Kobayashi, K. Itoh, T. Ido, K. Kamiya, S. -I. Itoh, Y. Miura, Y. Nagashima, A. Fujisawa, S. Inagaki, K. Ida, K. Hoshino

    NUCLEAR FUSION   57 ( 7 )   2017.7

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/1741-4326/aa5d03

  • Suppression of Trapped Energetic Ions Driven Resistive Interchange Modes with Electron Cyclotron Heating in a Helical Plasma Reviewed

    X. D. Du, K. Toi, S. Ohdachi, K. Y. Watanabe, H. Takahashi, Y. Yoshimura, M. Osakabe, R. Seki, T. Nicolas, H. Tsuchiya, K. Nagaoka, K. Ogawa, K. Tanaka, M. Isobe, M. Yokoyama, M. Yoshinuma, S. Kubo, S. Sakakibara, T. Bando, T. Ido, T. Ozaki, Y. Suzuki, Y. Takemura

    Physical Review Letters   118 ( 12 )   2017.3

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1103/PhysRevLett.118.125001

  • 2D spatial profile measurements of potential fluctuation with heavy ion beam probe on the Large Helical Device Reviewed

    A. Shimizu, T. Ido, T. Ido, M. Nishiura, S. Kato, K. Ogawa, K. Ogawa, H. Takahashi, H. Takahashi, H. Igami, Y. Yoshimura, S. Kubo, T. Shimozuma

    Review of Scientific Instruments   87 ( 11 )   2016.11

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    2D spatial profile measurements of potential fluctuation with heavy ion beam probe on the Large Helical Device
    © 2016 Author(s).Two-dimensional spatial profiles of potential fluctuation were measured with the heavy ion beam probe (HIBP) in the Large Helical Device (LHD). For 2D spatial profile measurements, the probe beam energy has to be changed, which requires the adjustment of many deflectors in the beam transport line to optimize the beam trajectory, since the transport line of LHD-HIBP system is long. The automatic beam adjustment system was developed, which allows us to adjust the beam trajectory easily. By analyzing coherence between potential fluctuation and magnetic probe signal, the noise level of the mode power spectrum of the potential fluctuation can be reduced. By using this method, the 2D spatial profile of potential fluctuation profile was successfully obtained.

    DOI: 10.1063/1.4963908

  • Resistive interchange mode destabilized by helically trapped energetic ions and its effects on energetic ions and bulk plasma in a helical plasma Reviewed

    X. D. Du, K. Toi, S. Ohdachi, M. Osakabe, T. Ido, K. Tanaka, M. Yokoyama, M. Yoshinuma, K. Ogawa, K. Y, Watanabe, T. Akiyama, M. Isobe, K. Nagaoka, T. Ozaki, S. Sakakibara, R. Seki, A. Shimizu, Y. Suzuki, H. Tsuchiya

    Nuclear Fusion   56 ( 1 )   2016.11

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    Resistive interchange mode destabilized by helically trapped energetic ions and its effects on energetic ions and bulk plasma in a helical plasma
    © 2016 IAEA, Vienna. A resistive interchange mode of the structure (, : poloidal and toroidal mode numbers, respectively) with a bursting character and rapid frequency chirping in the range less than 10 kHz is observed for the first time in the edge region of the net current-free, low beta LHD (Large Helical Device) plasmas during high power injection of perpendicular neutral beams. The mode resonates with the precession motion of helically trapped energetic ions (EPs), following the resonant condition. The radial mode structure is recognized to be similar to that of the pressure-driven resistive interchange mode, of which radial displacement eigenfunction quite localizes around the mode rational surface, and evolves into an odd-type (or island-type) during the late of frequency chirping phase. This beam driven mode is excited when the beta value of helically trapped EPs exceeds a certain threshold. This instability is thought to be a new branch of resistive interchange mode destabilized by the trapped energetic ions. The radial transport, i.e. redistribution and losses, of helically trapped energetic ions induced by the mode transiently generates significant radial electric field near the plasma peripheral region. The large shear of thus generated radial electric field is thought to contribute to the observed suppression of micro-turbulence and transient increases of the temperature of fully ionized carbon impurity ions and electron density, suggesting improvement of bulk plasma confinement.

    DOI: 10.1088/0029-5515/56/1/016002

  • Experimental Identification of Electric Field Excitation Mechanisms in a Structural Transition of Tokamak Plasmas Reviewed

    T. Kobayashi, K. Itoh, T. Ido, K. Kamiya, S. -I. Itoh, Y. Miura, Y. Nagashima, A. Fujisawa, S. Inagaki, K. Ida, K. Hoshino

    Scientific Reports   6   2016.8

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1038/srep30720

  • On the Origin of Steep and Localized Radial Electric Field in the Transport Barrier at Plasma Edge Reviewed

    K. Itoh, S. I. Itoh, T. Kobayashi, K. Kamiya, T. Ido, T. Tokuzawa, S. Inagaki, N. Kasuya

    Contributions to Plasma Physics   56 ( 6-8 )   522 - 527   2016.8

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1002/ctpp.201610042

  • Transition from chirping to steady NBI-driven Alfvén modes caused by magnetic configuration variations in the TJ-II stellarator Reviewed

    A. V. Melnikov, L. G. Eliseev, E. Ascasíbar, A. Cappa, F. Castejón, C. Hidalgo, T. Ido, J. A. Jiménez, A. S. Kozachek, L. I. Krupnik, M. Liniers, S. E. Lysenko, K. Nagaoka, J. L. De Pablos, A. Shimizu, S. E. Sharapov, M. V. Ufimtsev, S. Yamamoto

    56 ( 7 )   2016.6

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    Beam-driven Alfvén eigenmodes (AEs) have been studied in the TJ-II low-magnetic-shear flexible heliac (B 0 = 0.95 T, R = 1.5 m, a = 0.22 m), in L-mode hydrogen plasmas with hydrogen NBI and ECR heating (P NBI 1.0 MW, E NBI = 32 keV, P ECRH 0.6 MW). In low-density plasmas in the range = (0.3-1.5) ×1019 m-3, a large variety of AEs have been observed in the plasma core with the heavy ion beam probe diagnostic and Mirnov coils, in the frequency range 50 kHz < f AE < 380 kHz. In experiments in which the vacuum rotational transform is varied during the shot (dynamic configuration scan), some AEs exhibit changes in their nonlinear evolution from bursting-amplitude AEs with chirping frequency to steady-frequency AEs, and back. The range of intervals within which the AEs studied are chirping or steady-state is determined.

    DOI: 10.1088/0029-5515/56/7/076001

  • Onset condition of the subcritical geodesic acoustic mode instability in the presence of energetic-particle-driven geodesic acoustic mode Reviewed

    K. Itoh, S. I. Itoh, Y. Kosuga, M. Lesur, T. Ido

    Plasma Physics Reports   42 ( 5 )   418 - 423   2016.5

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1134/S1063780X16050056

  • Nonlinear excitation of subcritical fast ion-driven modes Reviewed

    M. Lesur, M. Lesur, K. Itoh, K. Itoh, T. Ido, S. I. Itoh, S. I. Itoh, Y. Kosuga, Y. Kosuga, M. Sasaki, S. Inagaki, S. Inagaki, M. Osakabe, M. Osakabe, K. Ogawa, K. Ogawa, A. Shimizu, K. Ida, K. Ida

    Nuclear Fusion   56 ( 5 )   2016.4

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    Nonlinear excitation of subcritical fast ion-driven modes
    © 2016 IAEA, Vienna.In collisionless plasma, it is known that linearly stable modes can be destabilized (subcritically) by the presence of structures in phase-space. The growth of such structures is a nonlinear, kinetic mechanism, which provides a channel for free-energy extraction, different from conventional inverse Landau damping. However, such nonlinear growth requires the presence of a seed structure with a relatively large threshold in amplitude. We demonstrate that, in the presence of another, linearly unstable (supercritical) mode, wave-wave coupling can provide a seed, which can lead to subcritical instability by either one of two mechanisms. Both mechanisms hinge on a collaboration between fluid nonlinearity and kinetic nonlinearity. If collisional velocity diffusion is low enough, the seed provided by the supercritical mode overcomes the threshold for nonlinear growth of phase-space structure. Then, the supercritical mode triggers the conventional subcritical instability. If collisional velocity diffusion is too large, the seed is significantly below the threshold, but can still grow by a sustained collaboration between fluid and kinetic nonlinearities. Both of these subcritical instabilities can be triggered, even when the frequency of the supercritical mode is rapidly sweeping. These results were obtained by modeling the subcritical mode kinetically, and the impact of the supercritical mode by simple wave-wave coupling equations. This model is applied to bursty onset of geodesic acoustic modes in an LHD experiment. The model recovers several key features such as relative amplitude, timescales, and phase relations. It suggests that the strongest bursts are subcritical instabilities, with sustained collaboration between fluid and kinetic nonlinearities.

    DOI: 10.1088/0029-5515/56/5/056009

  • Nonlinear Excitation of Subcritical Instabilities in a Toroidal Plasma Reviewed

    M. Lesur, K. Itoh, T. Ido, M. Osakabe, K. Ogawa, A. Shimizu, M. Sasaki, K. Ida, S. Inagaki, S. -I. Itoh

    PHYSICAL REVIEW LETTERS   116 ( 1 )   2016.1

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1103/PhysRevLett.116.015003

  • Contribution of geodesic acoustic modes in the limit cycle oscillation near H-mode transition in JFT-2M plasmas Reviewed

    K. Itoh, T. Kobayashi, T. Ido, S-I Itoh, K. Kamiya

    PLASMA PHYSICS AND CONTROLLED FUSION   57 ( 9 )   2015.9

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0741-3335/57/9/092001

  • Simulation study of high-frequency energetic particle driven geodesic acoustic mode

    Hao Wang, Yasushi Todo, Takeshi Ido, Masaki Osakabe

    Physics of Plasmas   22 ( 9 )   2015.9

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/1.4930130

  • Integrated discharge scenario for high-temperature helical plasma in LHD Reviewed

    K. Nagaoka, H. Takahashi, S. Murakami, H. Nakano, Y. Takeiri, H. Tsuchiya, M. Osakabe, K. Ida, M. Yokoyama, M. Yoshinuma, S. Morita, M. Goto, T. Oishi, N. Pablant, K. Fujii, K. Tanaka, N. Tamura, Y. Nakamura, X. Du, T. Ido, A. Shimizu, S. Kubo, H. Igami, R. Seki, C. Suzuki, Y. Suzuki, K. Tsumori, K. Ikeda, M. Kisaki, Y. Yoshimura, T. Shimozuma, T. Seki, K. Saito, H. Kasahara, S. Kamio, T. Mutoh, O. Kaneko, H. Yamada, A. Komori

    Nuclear Fusion   55 ( 11 )   2015.9

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0029-5515/55/11/113020

  • Identification of the energetic-particle driven GAM in the LHD Reviewed International journal

    Nuclear Fusion   55   083024   2015.7

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0029-5515/55/8/083024

    Other Link: https://iopscience.iop.org/article/10.1088/0029-5515/55/8/083024

  • Overview of transport and MHD stability study: Focusing on the impact of magnetic field topology in the Large Helical Device

    K. Ida, K. Nagaoka, S. Inagaki, H. Kasahara, T. Evans, M. Yoshinuma, K. Kamiya, S. Ohdach, M. Osakabe, M. Kobayashi, S. Sudo, K. Itoh, T. Akiyama, M. Emoto, A. Dinklage, X. Du, K. Fujii, M. Goto, T. Goto, M. Hasuo, C. Hidalgo, K. Ichiguchi, A. Ishizawa, M. Jakubowski, G. Kawamura, D. Kato, S. Morita, K. Mukai, I. Murakami, S. Murakami, Y. Narushima, M. Nunami, N. Ohno, N. Pablant, S. Sakakibara, T. Seki, T. Shimozuma, M. Shoji, K. Tanaka, T. Tokuzawa, Y. Todo, H. Wang, M. Yokoyama, H. Yamada, Y. Takeiri, T. Mutoh, S. Imagawa, T. Mito, Y. Nagayama, K. Y. Watanabe, N. Ashikawa, H. Chikaraishi, A. Ejiri, M. Furukawa, T. Fujita, S. Hamaguchi, H. Igami, M. Isobe, S. Masuzaki, T. Morisaki, G. Motojima, K. Nagasaki, H. Nakano, Y. Oya, C. Suzuki, Y. Suzuki, R. Sakamoto, M. Sakamoto, A. Sanpei, H. Takahashi, H. Tsuchiya, M. Tokitani, Y. Ueda, Y. Yoshimura, S. Yamamoto, K. Nishimura, H. Sugama, T. Yamamoto, H. Idei, A. Isayama, S. Kitajima, S. Masamune, K. Shinohara, P. S. Bawankar, E. Bernard, M. Von Berkel, H. Funaba, X. L. Huang, T. Ii, T. Ido, K. Ikeda, S. Kamio, R. Kumazawa, T. Kobayashi, C. Moon, S. Muto, J. Miyazawa, T. Ming, Y. Nakamura, S. Nishimura

    Nuclear Fusion   55 ( 10 )   2015.7

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0029-5515/55/10/104018

  • Edge plasma dynamics during L-H transition in the JFT-2M tokamak Reviewed

    T. Kobayashi, K. Itoh, T. Ido, K. Kamiya, S. -I. Itoh, Y. Miura, Y. Nagashima, A. Fujisawa, S. Inagaki, K. Ida, K. Hoshino

    NUCLEAR FUSION   55 ( 6 )   2015.6

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0029-5515/55/6/063009

  • Microtearing mode (MTM) turbulence in JIPPT-IIU tokamak plasmas Reviewed

    Y. Hamada, T. Watari, A. Nishizawa, O. Yamagishi, K. Narihara, K. Ida, Y. Kawasumi, T. Ido, M. Kojima, K. Toi

    NUCLEAR FUSION   55 ( 4 )   2015.4

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0029-5515/55/4/043008

  • Resistive interchange modes destabilized by helically trapped energetic ions in a helical plasma Reviewed

    X. D. Du, K. Toi, M. Osakabe, S. Ohdachi, T. Ido, K. Tanaka, M. Yokoyama, M. Yoshinuma, K. Ogawa, K. Y, Watanabe, M. Isobe, K. Nagaoka, T. Ozaki, S. Sakakibara, R. Seki, A. Shimizu, Y. Suzuki, H. Tsuchiya

    Physical Review Letters   114 ( 15 )   2015.4

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    Resistive interchange modes destabilized by helically trapped energetic ions in a helical plasma
    © 2015 American Physical Society. A new bursting m=1/n=1 instability (m,n: poloidal and toroidal mode numbers) with rapid frequency chirping down has been observed for the first time in a helical plasma with intense perpendicular neutral beam injection. This is destabilized in the plasma peripheral region by resonant interaction between helically trapped energetic ions and the resistive interchange mode. A large radial electric field is induced near the edge due to enhanced radial transport of the trapped energetic ions by the mode, and leads to clear change in toroidal plasma flow, suppression of microturbulence, and triggering an improvement of bulk plasma confinement.

    DOI: 10.1103/PhysRevLett.114.155003

  • Flow damping due to stochastization of the magnetic field

    K. Ida, M. Yoshinuma, H. Tsuchiya, T. Kobayashi, C. Suzuki, M. Yokoyama, A. Shimizu, K. Nagaoka, S. Inagaki, K. Itoh, T. Akiyama, M. Emoto, T. Evans, A. Dinklage, X. Du, K. Fujii, M. Goto, T. Goto, M. Hasuo, C. Hidalgo, K. Ichiguchi, A. Ishizawa, M. Jakubowski, K. Kamiya, H. Kasahara, G. Kawamura, D. Kato, M. Kobayashi, S. Morita, K. Mukai, I. Murakami, S. Murakami, Y. Narushima, M. Nunami, S. Ohdach, N. Ohno, M. Osakabe, N. Pablant, S. Sakakibara, T. Seki, T. Shimozuma, M. Shoji, S. Sudo, K. Tanaka, T. Tokuzawa, Y. Todo, H. Wang, H. Yamada, Y. Takeiri, T. Mutoh, S. Imagawa, T. Mito, Y. Nagayama, K. Y. Watanabe, N. Ashikawa, H. Chikaraishi, A. Ejiri, M. Furukawa, T. Fujita, S. Hamaguchi, H. Igami, M. Isobe, S. Masuzaki, T. Morisaki, G. Motojima, K. Nagasaki, H. Nakano, Y. Oya, Y. Suzuki, R. Sakamoto, M. Sakamoto, A. Sanpei, H. Takahashi, M. Tokitani, Y. Ueda, Y. Yoshimura, S. Yamamoto, K. Nishimura, H. Sugama, T. Yamamoto, H. Idei, A. Isayama, S. Kitajima, S. Masamune, K. Shinohara, P. S. Bawankar, E. Bernard, M. Von Berkel, H. Funaba, X. L. Huang, T. Ii, T. Ido, K. Ikeda, S. Kamio, R. Kumazawa, C. Moon, S. Muto, J. Miyazawa, T. Ming, Y. Nakamura

    Nature Communications   6   2015.1

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1038/ncomms6816

  • 2D potential measurements by applying automatic beam adjustment system to heavy ion beam probe diagnostic on the Large Helical Device Reviewed

    A. Shimizu, T. Ido, M. Kurachi, R. Makino, M. Nishiura, S. Kato, A. Nishizawa, Y. Hamada

    REVIEW OF SCIENTIFIC INSTRUMENTS   85 ( 11 )   2014.11

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/1.4891975

  • Dynamics of edge limit cycle oscillation in the JFT-2M Tokamak

    T. Kobayashi, K. Itoh, T. Ido, K. Kamiya, S. I. Itoh, Y. Miura, Y. Nagashima, A. Fujisawa, S. Inagaki, K. Ida, N. Kasuya, K. Hoshino

    Nuclear Fusion   54 ( 7 )   2014.7

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0029-5515/54/7/073017

  • Extension of high T <inf>e</inf> regime with upgraded electron cyclotron resonance heating system in the Large Helical Device

    H. Takahashi, T. Shimozuma, S. Kubo, Y. Yoshimura, H. Igami, S. Ito, S. Kobayashi, Y. Mizuno, K. Okada, T. Mutoh, K. Nagaoka, S. Murakami, M. Osakabe, I. Yamada, H. Nakano, M. Yokoyama, T. Ido, A. Shimizu, R. Seki, K. Ida, M. Yoshinuma, T. Kariya, R. Minami, T. Imai, N. B. Marushchenko, Y. Turkin

    Physics of Plasmas   21 ( 6 )   2014.6

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/1.4884365

  • Observation of multi-scale turbulence and non-local transport in LHD plasmas

    T. Tokuzawa, S. Inagaki, K. Ida, K. Itoh, T. Ido, A. Shimizu, H. Takahashi, S. Kitajima, N. Tamura, M. Yoshinuma, H. Tsuchiya, I. Yamada, K. Tanaka, T. Akiyama, Y. Nagayama, K. Kawahata, K. Y. Watanabe, H. Yamada

    Physics of Plasmas   21 ( 5 )   2014.5

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/1.4876619

  • How is turbulence intensity determined by macroscopic variables in a toroidal plasma? Reviewed

    S. Inagaki, T. Tokuzawa, N. Tamura, S. -I. Itoh, T. Kobayashi, K. Ida, T. Shimozuma, S. Kubo, K. Tanaka, T. Ido, A. Shimizu, H. Tsuchiya, N. Kasuya, Y. Nagayama, K. Kawahata, S. Sudo, H. Yamada, A. Fujisawa, K. Itoh

    NUCLEAR FUSION   53 ( 11 )   2013.11

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0029-5515/53/11/113006

  • Extension of operation regimes and investigation of three-dimensional currentless plasmas in the Large Helical Device

    O. Kaneko, H. Yamada, S. Inagaki, M. Jakubowski, S. Kajita, S. Kitajima, Kobayashi, K. Koga, T. Morisaki, S. Morita, T. Mutoh, S. Sakakibara, Y. Suzuki, H. Takahashi, K. Tanaka, K. Toi, Y. Yoshimura, T. Akiyama, Y. Asahi, N. Ashikawa, H. Chikaraishi, A. Cooper, D. S. Darrow, E. Drapiko, P. Drewelow, X. Du, A. Ejiri, M. Emoto, T. Evans, N. Ezumi, K. Fujii, T. Fukuda, H. Funaba, M. Furukawa, D. A. Gates, M. Goto, T. Goto, W. Guttenfelder, S. Hamaguchi, M. Hasuo, T. Hino, Y. Hirooka, K. Ichiguchi, K. Ida, H. Idei, T. Ido, H. Igami, K. Ikeda, S. Imagawa, T. Imai, M. Isobe, M. Itagaki, T. Ito, K. Itoh, S. Itoh, A. Iwamoto, K. Kamiya, T. Kariya, H. Kasahara, N. Kasuya, D. Kato, T. Kato, K. Kawahata, F. Koike, S. Kubo, R. Kumazawa, D. Kuwahara, S. Lazerson, H. Lee, S. Masuzaki, S. Matsuoka, H. Matsuura, A. Matsuyama, C. Michael, D. Mikkelsen, O. Mitarai, T. Mito, J. Miyazawa, G. Motojima, K. Mukai, A. Murakami, I. Murakami, S. Murakami, T. Muroga, S. Muto, K. Nagaoka, K. Nagasaki, Y. Nagayama, N. Nakajima, H. Nakamura, Y. Nakamura, H. Nakanishi, H. Nakano, T. Nakano, K. Narihara, Y. Narushima, K. Nishimura, S. Nishimura, M. Nishiura, Y. M. Nunami

    Nuclear Fusion   53 ( 10 )   2013.10

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0029-5515/53/10/104015

  • Spatiotemporal Structures of Edge Limit-Cycle Oscillation before L-to-H Transition in the JFT-2M Tokamak Reviewed

    T. Kobayashi, K. Itoh, T. Ido, K. Kamiya, S. -I. Itoh, Y. Miura, Y. Nagashima, A. Fujisawa, S. Inagaki, K. Ida, K. Hoshino

    PHYSICAL REVIEW LETTERS   111 ( 3 )   2013.7

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1103/PhysRevLett.111.035002

  • Regions of kinetic geodesic acoustic modes and streamers in JIPPT-IIU tokamak plasmas Reviewed

    Y. Hamada, T. Watari, A. Nishizawa, O. Yamagishi, K. Narihara, Y. Kawasumi, T. Ido, M. Kojima, K. Toi

    NUCLEAR FUSION   52 ( 6 )   2012.6

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0029-5515/52/6/063023

  • Long range temperature fluctuation in LHD Reviewed

    Shigeru Inagaki, Tokihiko Tokuzawa, Kimitaka Itoh, Katsumi Ida, Sanae I. Itoh, Naoki Tamura, Satoru Sakakibara, Naohiro Kasuya, Akihide Fujisawa, Shin Kubo, Takashi Shimozuma, Takeshi Ido, Seiya Nishimura, Hiroyuki Arakawa, Tatsuya Kobayashi, Masatoshi Yagi, Kenji Tanaka, Yoshio Nagayama, Kazuo Kawahata, Shigeru Sudo, Hiroshi Yamada, Akio Komori

    Plasma and Fusion Research   6   2011.12

     More details

    Language:Others  

    Long range temperature fluctuation in LHD
    We report a detailed correlation technique to identify the long-range temperature fluctuation in the Large Helical Device. Correlation hunting has successfully realized the observation of electron temperature fluctuations, which are characterized by their correlation length comparable to the plasma minor radius, with low frequency of ~ 1-3kHz, ballistic radial propagation (at a speed of ~1km/s, of the order of diamagnetic drift velocity), spatial mode number of m/n = 1/1 (or 2/1), and amplitude of ~2% at the maximum. Bicoherence analysis confirmed their nonlinear coupling with local microscopic turbulent fluctuations. This long-range temperature fluctuation is a possible carrier of fast propagation in transport processes observed so far. We also comment on the theoretical interpretation. © 2011 The Japan Society of Plasma Science and Nuclear Fusion Research.

    DOI: 10.1585/pfr.6.1402017

  • A New Simulation Method of Geodesic Acoustic Mode in Toroidal Plasmas by Using Band-Limited White Noise in a δf Neoclassical Transport Code Reviewed

    2 ( 0 )   72   2011.10

     More details

    Language:Others  

    DOI: 10.15669/pnst.2.72

  • Observation of Long-Distance Radial Correlation in Toroidal Plasma Turbulence Reviewed

    S. Inagaki, T. Tokuzawa, K. Itoh, K. Ida, S. -I. Itoh, N. Tamura, S. Sakakibara, N. Kasuya, A. Fujisawa, S. Kubo, T. Shimozuma, T. Ido, S. Nishimura, H. Arakawa, T. Kobayashi, K. Tanaka, Y. Nagayama, K. Kawahata, S. Sudo, H. Yamada, A. Komori

    PHYSICAL REVIEW LETTERS   107 ( 11 )   2011.9

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1103/PhysRevLett.107.115001

  • Heat and momentum transport of ion internal transport barrier plasmas on the Large Helical Device Reviewed

    K. Nagaoka, K. Ida, M. Yoshinuma, Y. Takeiri, M. Yokoyama, S. Morita, K. Tanaka, T. Ido, A. Shimizu, N. Tamura, H. Funaba, S. Murakami, M. Goto, H. Takahashi, C. Suzuki, Y. Suzuki, K. Ikeda, M. Osakabe, K. Tsumori, H. Nakano, O. Kaneko, H. Yamada

    NUCLEAR FUSION   51 ( 8 )   2011.8

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0029-5515/51/8/083022

  • 金イオンビームとガスターゲットの衝突時の反応断面積測定システムの作製

    谷池 晃, 忍 友彰, 望月 翔, 井戸 毅, 西浦 正樹, 清水 昭博, 古山 雄一, 北村 晃

    神戸大学大学院海事科学研究科紀要 = Review of the Faculty of Maritime Sciences, Kobe University   8   47 - 58   2011.7

     More details

    Language:Japanese  

    DOI: 10.24546/81003310

  • Potential fluctuation associated with the energetic-particle-induced geodesic acoustic mode in the Large Helical Device Reviewed International journal

    51   073046   2011.6

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    Geodesic acoustic modes (GAM) driven by energetic particles are observed in the Large Helical Device (LHD) by a heavy ion beam probe. The GAM localizes near the magnetic axis. It is confirmed that the energetic-particle-induced GAM is accompanied by an electrostatic potential fluctuation and radial electric field fluctuation. The amplitude of the potential fluctuation is several hundred volts, and it is much larger than the potential fluctuation associated with turbulence-induced GAMs observed in the edge region in tokamak plasmas. The energetic-particle-induced GAM modulates the amplitude of the density fluctuation in a high-frequency range. The observed GAM frequency is constant at the predicted GAM frequency in plasmas with reversed magnetic shear. On the other hand, it shifts upwards from the predicted GAM frequency in plasmas with monotonic magnetic shear.

    DOI: 10.1088/0029-5515/51/7/073046

    Other Link: https://iopscience.iop.org/article/10.1088/0029-5515/51/7/073046

  • Detection of the kinetic geodesic acoustic mode (KGAM) near the centre region of JIPPT-IIU tokamak plasmas Reviewed

    Y. Hamada, T. Watari, A. Nishizawa, O. Yamagishi, K. Narihara, K. Ida, Y. Kawasumi, T. Ido, M. Kojima, K. Toi

    NUCLEAR FUSION   51 ( 3 )   2011.3

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0029-5515/51/3/033005

  • Production of Sub-MeV Positive Gold Ion Beams with Various Gas Targets to Improve the Tandem Accelerator of the LHD-HIBP Reviewed

    Akira Taniike, Takeshi Ido, Masaki Nishiura, Akihiro Shimizu, Yuichi Furuyama, Akira Kitamura

    Plasma and Fusion Research   5, S2087 (2010)   2010.12

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    Production of Sub-MeV Positive Gold Ion Beams with Various Gas Targets to Improve the Tandem Accelerator of the LHD-HIBP

    DOI: 10.1585/pfr.5.S2087

  • Observation of reversed-shear Alfvén eigenmodes excited by energetic ions in a helical plasma Reviewed

    105 ( 14 )   2010.10

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    Reversed-shear Alfvén eigenmodes were observed for the first time in a helical plasma having negative q0′′ (the curvature of the safety factor q at the zero shear layer). The frequency is swept downward and upward sequentially via the time variation in the maximum of q. The eigenmodes calculated by ideal MHD theory are consistent with the experimental data. The frequency sweeping is mainly determined by the effects of energetic ions and the bulk pressure gradient. Coupling of reversed-shear Alfvén eigenmodes with energetic ion driven geodesic acoustic modes generates a multitude of frequency-sweeping modes. © 2010 The American Physical Society.

    DOI: 10.1103/PhysRevLett.105.145003

  • Potential measurements with heavy ion beam probe system on LHD Reviewed

    A. Shimizu, T. Ido, S. Nakamura, K. Toi, M. Nishiura, S. Kato

    REVIEW OF SCIENTIFIC INSTRUMENTS   81 ( 10 )   2010.10

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/1.3491317

  • Experimental study of radial electric field and electrostatic potential fluctuation in the Large Helical Device Invited Reviewed International journal

    52   124025   2010.9

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    A heavy ion beam probe was installed on the Large Helical Device (LHD) to investigate the roles of radial electric fields (Er ) in magnetically confined high-temperature plasmas. Two new observations are presented. One is the observation of electrostatic potential profiles during the formation of extremely hollow density profiles of impurities, called the impurity hole (Ida K et al 2009 Phys. Plasmas 16 056111), in the LHD plasmas. The measured Er is negative, and the Er determined by the ambipolarity condition of neoclassical particle fluxes is consistent with this observation. However, the transport analysis indicates that the formation of the extremely hollow profile is not attributable to the impurity fluxes driven by Er and the density and temperature gradients of the impurity. The other new observation is on the geodesic acoustic mode (GAM). The electrostatic potential fluctuation associated with the GAM, which is probably induced by energetic particles, in plasmas with the reversed or weak magnetic shear is identified. The GAM is localized in the core region of the plasma.

    DOI: 10.1088/0741-3335/52/12/124025

    Other Link: https://iopscience.iop.org/article/10.1088/0741-3335/52/12/124025

  • 24pQJ-3 イオンITBプラズマにおける熱・運動量輸送特性(24pQJ 核融合プラズマ(輸送・閉じ込め(2)/揺動・乱流特性),領域2(プラズマ基礎・プラズマ科学・核融合プラズマ・プラズマ宇宙物理))

    永岡 賢一, 居田 克巳, 吉沼 幹朗, 横山 雅之, 竹入 康彦, 森田 繁, 田中 謙治, 田村 直樹, 徳沢 季彦, 井戸 毅, 清水 昭博, 村上 定義, 中野 治久, 池田 勝則, 長壁 正樹, 津守 克嘉, 金子 修, LHD実験グループ

    日本物理学会講演概要集   65 ( 2 )   2010.8

     More details

    Language:Japanese  

  • GAM generation by drift waves in JIPP T-llU tokamak core plasmas Reviewed

    Y. Hamada, T. Watari, A. Nishizawa, O. Yamagishi, K. Narihara, Y. Kawasumi, T. Ido, M. Kojima, K. Toi

    NUCLEAR FUSION   50 ( 2 )   2010.2

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0029-5515/50/2/025001

  • Development of a heavy ion beam probe for measuring electrostatic potential profile and its fluctuation in LHD Reviewed International journal

    Takeshi Ido, Akihiro Shimizu, Masaki Nishiura, Haruhisa Nakano, Shinji Kato, Shinsuke Ohshima, Yasuo Yoshimura, Shin Kubo, Takashi Shimozuma, Hiroe Igami, Hiromi Takahashi, Kazuo Toi, Fumitake Watanabe, Kazumichi Narihara and Ichihiro Yamada

    Plasma Science and Technology   11   460 - 464   2009.8

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/1009-0630/11/4/19

  • DEVELOPMENT OF 6-MeV HEAVY ION BEAM PROBE ON LHD Invited Reviewed International journal

    T. IDO, A. SHIMIZU, M. NISHIURA, S. KATO, H. NAKANO, S. OHSHIMA, M. YOKOYAMA, S. MURAKAMI, A. WAKASA, S. NAKAMURA, M. YOKOTA, K. TSUKADA, H. OGAWA, T. INOUE, and LHD EXPERIMENT GROUP

    Fusion Science and Technology   58   436   2009.7

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.13182/FST10-A10829

    Other Link: https://www.tandfonline.com/doi/abs/10.13182/FST10-A10829

  • Extension of Improved Particle and Energy Confinement Regime in the Core of LHD Plasma Reviewed

    KANEKO Osamu, EMOTO Masahiko, FUNABA Hisamichi, GONCHAROV Pavel, GOTO Motoshi, GOTO Takuya, HAMAGUCHI Shinji, ICHIGUCHI Katsuji, IDO Takeshi, IGAMI Hiroe, IKEDA Katsunori, YOKOYAMA Masayuki, IMAGAWA Shinsaku, ISOBE Mitsutaka, ITOH Kimitaka, IWAMOTO Akifumi, KANNO Ryutaro, KASAHARA Hiroshi, KASUYA Naohiro, KATO Daiji, KAWAHATA Kazuo, KOBAYASHI Masahiro, YOSHINUMA Mikiro, KUBO Shin, KUMAZAWA Ryuhei, MAEKAWA Ryuji, MASUZAKI Suguru, MITO Toshiyuki, MIYAZAWA Jun-ichi, MIZUGUCHI Naoki, MORISAKI Tomohiro, MORITA Shigeru, MOTOJIMA Gen, NAGAOKA Ken-ichi, MUTO Sadatsugu, MUTOH Takashi, NAGAYAMA Yoshio, NAKAJIMA Noriyoshi, NAKAMURA Yukio, NAKANISHI Hideya, NARIHARA Kazumichi, NARUSHIMA Yoshiro, NISHIMURA Kiyohiko, NISHIURA Masaki, IDA Katsumi, OBANA Tetsuhiro, OHDACHI Satoshi, OHYABU Nobuyoshi, OSAKABE Masaki, OZAKI Tetsuo, PETERSON Byron J, SAGARA Akio, SAITO Kenji, SAKAKIBARA Satoru, SATAKE Shinsuke, SAKAMOTO Ryuichi, SATO Kuninori, SEKI Tetsuo, SHIMIZU Akihiro, SHIMOZUMA Takashi, SHOJI Mamoru, SUDO Shigeru, SUGAMA Hideo, SUZUKI Chihiro, SUZUKI Yasuhiro, TAKAHASHI Hiromi, AKIYAMA Tsuyoshi, TAKAHATA Kazuya, TAKEIRI Yasuhiko, TAMURA Hitoshi, TAMURA Naoki, TANAKA Kenji, TODA Shinichiro, TOI Kazuo, TOKITANI Masayuki, TOKUZAWA Tokihiko, TSUMORI Katsuyoshi, ASHIKAWA Naoko, WATANABE Kiyomasa, YAMADA Ichihiro, YAMADA Hiroshi, YAMAGISHI Osamu, YANAGI Nagato, YOSHIMURA Shinji, YOSHIMURA Yasuo, KOMORI Akio, CHIKARAISHI Hirotaka

    Plasma and Fusion Research   4   27 - 27   2009.1

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    Extension of Improved Particle and Energy Confinement Regime in the Core of LHD Plasma
    Recent two major topics of Large Helical Device (LHD) towards fusion relevant conditions, high-density operation and high-ion-temperature operation, are reported. Super dense core plasma was obtained by the combination of repetitive hydrogen ice pellet injection and high power neutral beam injection (NBI) heating. A very peaked density profile with the highest central density of 1.1 &times; 1021 m-3 was produced showing that the particle transport was suppressed very well in the plasma core. The spatial density profile varies as the position of magnetic axis (Rax), and the steepest profile is obtained at Rax = 3.95 m. The highest central ion temperature of 5.6 keV was obtained in hydrogen plasma at electron density of 1.6 &times; 1019 m-3 by NBI, where a peaked ion-temperature profile with internal ion energy transport barrier was observed. The profile of electron temperature did not change much and was broad even when the ion temperature had a peaked profile. The central ion temperature is higher than the electron temperature, which is a new operation regime of LHD. High central ion temperature accompanied strong toroidal rotation and an extreme hollow profile of carbon ions (impurity hole). These steep temperature profiles were obtained so far at around Rax = 3.6 m. The compatibility between particle and energy confinement is a new issue of LHD to explore a new operation regime for attractive fusion reactor.

    DOI: 10.1585/pfr.4.027

  • Measurements of spatial structure of plasma potential and density fluctuations by multichannel heavy ion beam probe on large helical device Reviewed

    Shinsuke Ohshima, Takeshi Ido, Akihiro Shimizu, Masaki Nishiura, Haruhisa Nakano

    Review of Scientific Instruments   79 ( 10 )   10F320   2008.10

     More details

    Language:English  

    Measurements of spatial structure of plasma potential and density fluctuations by multichannel heavy ion beam probe on large helical device

    DOI: 10.1063/1.2981177

  • Measurement of Electrostatic Potential Fluctuation using Heavy Ion Beam Probe in Large Helical Device Reviewed International journal

    Takeshi Ido, Akihiro Shimizu, Masaki Nishiura, Haruhisa Nakano, Shinsuke Ohshima, Shinji Kato, Yasuji Hamada, Yasuo Yoshimura, Shin Kubo, Takashi Shimozuma, Hiroe Igami, Hiromi Takahashi, Kazuo Toi, and Fumitake Watanabe

    Review of Scientific Instruments   79   10F318   2008.7

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/1.2971207

  • Experimental studies of zonal flow and field in compact helical system plasma Reviewed

    A. Fujisawa, K. Itoh, A. Shimizu, H. Nakano, S. Ohshima, H. Iguchi, K. Matsuoka, S. Okamura, T. Minami, Y. Yoshimura, K. Nagaoka, K. Ida, K. Toi, C. Takahashi, M. Kojima, S. Nishimura, M. Isobe, C. Suzuki, T. Akiyama, T. Ido, Y. Nagashima, S. -I. Itoh, P. H. Diamond

    PHYSICS OF PLASMAS   15 ( 5 )   055906   2008.5

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/1.2889012

  • Status of the heavy ion beam probe system in the Large Helical Device Reviewed

    M. Nishiura, T. Ido, A. Shimizu, H. Nakano, T. Kato, S. Kato, Y. Hamada, V. P. Shevelko, R. K. Janev, M. Wada

    Review of Scientific Instruments   79   2008.3

     More details

    Language:Others  

    Status of the heavy ion beam probe system in the Large Helical Device
    A heavy ion beam probe (HIBP) system has been installed into the Large Helical Device (LHD) to measure the spatial profile of the plasma potential and density fluctuations. The optimization of the HIBP system, especially the beam injector, is described. The negative ion beam is required for the MeV beam production in a tandem accelerator. A sputter-type heavy negative ion source has been developed as an intense Au- beam source to produce Au+ beams with energy in the MeV range. The extraction electrodes and the Einzel lens system of the ion source have been designed taking into account the beam optics, and installed into the real machine. Throughout the plasma diagnostics on LHD experiments, the consumptions of vaporized caesium and gold target are being characterized for practical operations. In addition, the experimental charge fractions are compared with the theoretical fractions for understanding the charge-changing behavior of Au- ions and optimizing the fraction of Au+ ions at the exit of the tandem accelerator of the HIBP system. © 2008 American Institute of Physics.

    DOI: 10.1063/1.2819323

  • Experimental progress on zonal flow physics in toroidal plasmas Reviewed

    A. Fujisawa, T. Ido, A. Shimizu, S. Okamura, K. Matsuoka, H. Iguchi, Y. Hamada, H. Nakano, S. Ohshima, K. Itoh, K. Hoshino, K. Shinohara, Y. Miura, Y. Nagashima, S. I. Itoh, M. Shats, H. Xia, J. Q. Dong, L. W. Yan, K. J. Zhao, G. D. Conway, U. Stroth, A. V. Melnikov, L. G. Eliseev, S. E. Lysenko, S. V. Perfilov, C. Hidalgo, G. R. Tynan, C. Holland, P. H. Diamond, G. R. McKee, R. J. Fonck, D. K. Gupta, P. M. Schoch

    Nuclear Fusion   47   2007.10

     More details

    Language:Others  

    Experimental progress on zonal flow physics in toroidal plasmas
    The present status of experiments on zonal flows in magnetic confinement experiments is examined. The innovative use of traditional and modern diagnostics has revealed unambiguously the existence of zonal flows, their spatio-temporal characteristics, their relationship to turbulence and their effects on confinement. In particular, a number of observations have been accumulated on the oscillatory branch of zonal flows, named geodesic acoustic modes, suggesting the necessity for theories to give their proper description. In addition to these basic properties of zonal flows, several new methods have elucidated the processes of zonal flow generation from turbulence. Further investigation of the relationship between zonal flows and confinement is strongly encouraged as cross-device activity including low temperature, toroidal and linear devices. © 2007 IAEA.

    DOI: 10.1088/0029-5515/47/10/S19

  • In search of zonal flows by using direct density fluctuation measurements Reviewed

    Y. Nagashima, K. Itoh, S-I Itoh, A. Fujisawa, M. Yagi, K. Hoshino, K. Shinohara, A. Ejiri, Y. Takase, T. Ido, K. Uehara, Y. Miura

    PLASMA PHYSICS AND CONTROLLED FUSION   49 ( 10 )   1611 - 1625   2007.10

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0741-3335/49/10/002

  • Spatial resolution of the heavy ion beam probe on LHD Invited Reviewed International journal

    T. IDO, A. SHIMIZU, M. NISHIURA, Y. HAMADA, S. KATO, A. NISHIZAWA, H. NAKANO

    Plasma and Fusion Research   2   S1100   2007.3

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1585/pfr.2.S1100

  • Intermittent characteristics in coupling between turbulence and zonal flows Reviewed

    A. Fujisawa, A. Shimizu, H. Nakano, S. Ohshima, K. Itoh, Y. Nagashima, S. -I Itoh, H. Iguchi, Y. Yoshimura, T. Minami, K. Nagaoka, C. Takahashi, M. Kojima, S. Nishimura, M. Isobe, C. Suzuki, T. Akiyama, T. Ido, K. Matsuoka, S. Okamura, P. H. Diamond

    PLASMA PHYSICS AND CONTROLLED FUSION   49 ( 3 )   211 - 217   2007.3

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0741-3335/49/3/002

  • 6 MeV heavy ion beam probe on Large Helical Device Reviewed International journal

    T. Ido, A. Shimizu, M. Nishiura, A. Nishizawa, S. Katoh, K. Tsukada, M. Yokota, H. Ogawa, T. Inoue, Y. Hamada, T. P. Crowley, LHD Experimental Group

    Review of Scientific Instruments   77   10F523   2006.10

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/1.2338311

  • Turbulence and transport characteristics of a barrier in a toroidal plasma

    A Fujisawa, A Shimizu, H Nakano, S Ohsima, K Itoh, H Iguchi, Y Yoshimura, T Minami, K Nagaoka, C Takahashi, M Kojima, S Nishimura, M Isobe, C Suzuki, T Akiyama, Y Nagashima, K Ida, K Toi, T Ido, SI Itoh, K Matsuoka, S Okamura, PH Diamond

    PLASMA PHYSICS AND CONTROLLED FUSION   48 ( 4 )   S205 - S212   2006.4

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0741-3335/48/4/S15

  • Wavelet and Fourier analysis of zonal flows and density fluctuations in JIPP T-IIU tokamak plasmas Reviewed

    Y. Hamada, T. Watari, A. Nishizawa, T. Ido, M. Kojima, Y. Kawasumi, K. Toi

    PLASMA PHYSICS AND CONTROLLED FUSION   48 ( 4 )   S177 - S191   2006.4

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0741-3335/48/4/S13

  • Optimization of negative ion sources for a heavy-ion-beam probe

    Review of Scientific Instruments   77 ( 03A )   537 - 539   2006.3

     More details

    Language:Others  

    Optimization of negative ion sources for a heavy-ion-beam probe
    The development of plasma-sputter-type negative ion sources is underway for the heavy-ion-beam probe system as plasma diagnostic beams of the large helical device (LHD) for potential and fluctuation field measurements. Our purpose is to increase the doubly charged exchanged Au+ beam intensity to enhance the detection signal after passing through the plasmas of the LHD. For this purpose, the characterization of the Au- ion source and the beam optics has been carried out both experimentally and numerically. Based on these results, a new plasma-sputter-type negative ion source is designed and tested. © 2006 American Institute of Physics.

    DOI: 10.1063/1.2170094

  • Characteristics of plasma operation with the ferritic inside wall and its compatibility with high-performance plasmas in JFT-2M

    K. Tsuzuki, H. Kimura, Y. Kusama, M. Sato, H. Kawashima, K. Kamiya, K. Shinohara, H. Ogawa, K. Uehara, G. Kurita, S. Kasai, K. Hoshino, N. Isei, Y. Miura, M. Yamamoto, K. Kikuchi, T. Shibata, M. Bakhtiari, T. Hino, Y. Hirohata, Y. Yamauchi, K. Yamaguchi, H. Tsutsui, R. Shimada, H. Amemiya, Y. Nagashima, T. Ido, Y. Hamada

    Fusion Science and Technology   49 ( 2 )   197 - 208   2006.2

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.13182/FST06-A1095

  • Studies of radial electric field formation and its effect on fluctuations and transport barriers in the JFT-2M tokamak Reviewed

    K Ida, Y Miura, T Ido, Y Nagashima, K Shinohara

    FUSION SCIENCE AND TECHNOLOGY   49 ( 2 )   122 - 138   2006.2

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

  • Reduced divertor heat loads, plasma shape effects, and radial electric field structures in JFT-2M HRS H-mode plasmas Reviewed

    K Kamiya, H Kawashima, T Ido, N Oyama, M Bakhtiari, S Kasai, Y Kusama, Y Miura, H Ogawa, K Tsuzuki, K Uehara

    NUCLEAR FUSION   46 ( 2 )   272 - 276   2006.2

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0029-5515/46/2/010

  • Observation of nonlinear coupling between small-poloidal wave-number potential fluctuations and turbulent potential fluctuations in ohmically heated plasmas in the JFT-2M tokamak Reviewed

    Y Nagashima, K Hoshino, A Ejiri, K Shinohara, Y Takase, K Tsuzuki, K Uehara, H Kawashima, H Ogawa, T Ido, Y Kusama, Y Miura

    PHYSICAL REVIEW LETTERS   95 ( 9 )   2005.8

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

  • Zonal flows in the geodesic acoustic mode frequency range in the JIPP T-IIU tokamak plasmas Reviewed

    Y Hamada, A Nishizawa, T Ido, T Watari, M Kojima, Y Kawasumi, K Narihara, K Toi

    NUCLEAR FUSION   45 ( 2 )   81 - 88   2005.2

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0029-5515/45/2/002

  • Recent diagnostic developments on LHD

    S. Sudo, Y. Nagayama, B. J. Peterson, K. Kawahata, T. Akiyama, N. Ashikawa, M. Emoto, M. Goto, Y. Hamada, K. Ida, T. Ido, H. Iguchi, S. Inagaki, M. Isobe, T. Kobuchi, A. Komori, Y. Liang, S. Masuzaki, T. Minami, T. Morisaki, S. Morita, S. Muto, Y. Nakamura, H. Nakanishi, M. Narushima, K. Narihara, M. Nishiura, A. Nishizawa, S. Ohdachi, M. Osakabe, T. Ozaki, R. O. Pavlichenko, S. Sakakibara, K. Sato, M. Shoji, N. Tamura, K. Tanaka, K. Toi, T. Tokuzawa, K. Y. Watanabe, T. Watanabe, H. Yamada, I. Yamada, M. Yoshinuma, P. Goncharov, D. Kalinina, T. Kanaba, T. Sugimoto, A. Ejiri, Y. Ono, H. Hojo, K. Ishii, N. Iwama, Y. Kogi, A. Mase, M. Sakamoto, K. Kondo, H. Nagasaki, S. Yamamoto, N. Nishino, S. Okajima, T. Saida, M. Sasao, T. Takeda, S. Tsuji-Iio, D. S. Darrow, H. Takahashi, Y. Liu, J. F. Lyon, A. Yu Kostrioukov, V. B. Kuteev, V. Sergeev, I. Viniar, A. V. Krasilnikov, A. Sanin, L. N. Vyacheslavov, D. Stutman, M. Finkenthal, O. Motojima

    Plasma Physics and Controlled Fusion   45 ( 12 A )   2003.12

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0741-3335/45/12A/027

  • Calibration of heavy ion beam probe energy analyzer using mesh probe in the JFT-2M tokamak Reviewed

    K Kamiya, Y Miura, T Ido, Y Hamada

    REVIEW OF SCIENTIFIC INSTRUMENTS   74 ( 9 )   4206 - 4208   2003.9

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/1.1599057

  • Recent diagnostic developments on LHD

    S. Sudo, T. Ozaki, N. Ashikawa, M. Emoto, M. Goto, Y. Hamada, K. Ida, T. Ido, H. Iguchi, S. Inagaki, M. Isobe, K. Kawahata, K. Khlopenkov, T. Kobuchi, Y. Liang, S. Masuzaki, T. Minami, S. Morita, S. Muto, Y. Nagayama, H. Nakanishi, K. Narihara, A. Nishizawa, S. Ohdachi, M. Osakabe, B. J. Peterson, S. Sakakibara, M. Sasao, K. Sato, M. Shoji, N. Tamura, K. Tanaka, K. Toi, T. Tokuzawa, K. Watanabe, T. Watanabe, I. Yamada, P. Goncharov, A. Ejiri, S. Okajima, A. Mase, S. Tsuji-Iio, T. Akiyama, J. F. Lyon, L. N. Vyacheslavov, A. Sanin

    Plasma Physics and Controlled Fusion   45 ( 7 )   1127 - 1142   2003.7

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0741-3335/45/7/307

  • Observation of the fast potential change at L-H transition by a heavy-ion-beam probe on JFT-2M Reviewed

    T Ido, K Kamiya, Y Miura, Y Hamada, A Nishizawa, Y Kawasumi

    PHYSICAL REVIEW LETTERS   88 ( 5 )   2002.2

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1103/PhysRevLett.88.055006

    Other Link: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.88.055006

  • Relations among potential change, fluctuation change and transport barrier in the JFT-2M tokamak

    Y Miura, T Ido, K Kamiya, Y Hamada

    NUCLEAR FUSION   41 ( 8 )   973 - 979   2001.8

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0029-5515/41/8/301

  • Development of mesh probe for the calibration of the HIBP diagnostic system in the JFT-2M tokamak Reviewed

    K Kamiya, Y Miura, K Tsuzuki, T Ido, Y Hamada, T Nakayama

    REVIEW OF SCIENTIFIC INSTRUMENTS   72 ( 1 )   579 - 582   2001.1

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

  • Temporal behaviour of the potential and fluctuations at the L-H transition on JFT-2M Reviewed

    T Ido, K Kamiya, Y Miura, Y Hamada, A Nishizawa, Y Kawasumi

    PLASMA PHYSICS AND CONTROLLED FUSION   42   A309 - A315   2000.5

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

  • Behaviour of sample volumes of the heavy ion beam probe on JFT-2M Reviewed

    T Ido, K Kamiya, Y Hamada, A Nishizawa, Y Kawasumi, Y Miura

    PLASMA PHYSICS AND CONTROLLED FUSION   41 ( 8 )   1013 - 1024   1999.8

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0741-3335/41/8/307

  • Heavy ion beam probe diagnostic system on JFT-2M Reviewed

    T Ido, Y Hamada, A Nishizawa, Y Kawasumi, Y Miura, K Kamiya

    REVIEW OF SCIENTIFIC INSTRUMENTS   70 ( 1 )   955 - 958   1999.1

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/1.1149474

  • Strong electron heating in CHS ICRF heating experiments

    S. Masuda, R. Kumazawa, K. Nishimura, T. Mutoh, T. Watari, F. Simbo, T. Seki, T. Ido, R. Akiyama, A. Ando, A. Ejiri, H. Idei, K. Ida, H. Iguchi, M. Isobe, M. Iwase, S. Kubo, K. Matsuoka, T. Morisaki, S. Morita, S. Mutoh, S. Murakami, S. Okamura, T. Ozaki, S. Sakakibara, M. Sasao, C. Takahashi, T. Kawamoto, K. Tanaka, J. Xu, H. Yamada, I. Yamada, D. A. Rasmussen, J. F. Lyon, J. B. Wilgen, D. E. Greenwood, D. J. Hoffman, E. F. Jaeger, M. Murakami

    Nuclear Fusion   37 ( 1 )   53 - 68   1997.1

     More details

    Language:Others   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/0029-5515/37/1/I12

▼display all

Presentations

  • LHDにおいて垂直NBIにより形成される電位及び密度の空間構造

    井戸毅, 清水昭博, 西浦正樹, 田窪英法, 西澤章光

    第39回プラズマ・核融合学会年会  2022.11 

     More details

    Event date: 2022.11

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:富山   Country:Japan  

    近年不純物ホール等、不純物輸送の解明を契機として磁気面上における電位の非一様性の影響が注目されている。この非一様性を形成する要因の一つとして、高エネルギーの中性粒子入射(NBI)に起因する捕捉高速イオンの影響が数値シミュレーションに指摘されている(H. Yamaguchi and S. Murakami, Nucl. Fusion 58 016029 (2018))。本研究では、核融合科学研究所のLHDにおいて垂直NBIに対するプラズマ内部における電位分布及び密度分布の応答の計測を行った。
    図1に垂直NBIの有無に対する電位分布及び重イオンビームプローブ(HIBP)の信号強度分布の違いを示す。ここでHIBPの信号強度はプラズマの密度及び高速イオンの密度を反映する。電位分布、信号強度分布ともにNBI時に特徴的な空間構造が形成されることが観測された。この構造はNBが入射されている間は維持されており、再現性があることも確認された。また、LHDには2基の垂直NBIが設置されているが、上記の特徴的な構造は、計測位置からトロイダル方向に近い位置でのNBI時には顕著であるが、遠い位置でのNBI時には観測されない。この結果は、垂直NBI時にトロイダル方向に局在した電位構造が形成されており、磁気面上の非一様性の存在を示唆している。ただし、この構造は上記数値シミュレーションとは異なり、磁気軸近傍で顕著に現れる。今後この2次元構造や高速イオンの分布の解析を含め、物理機構を検討する必要がある。

  • Conceptual Design of a Heavy Ion Beam Probe for the QUEST spherical tokamak International conference

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

    24th Topical Conference on High Temperature Plasma Diagnostics  2022.5 

     More details

    Event date: 2022.5

    Language:English   Presentation type:Oral presentation (general)  

    Country:United States  

  • Dynamics of energetic particle-driven oscillatory zonal flow in toroidal plasmas Invited

    Takeshi Ido

    2021.11 

     More details

    Event date: 2021.11 - 2021.6

    Language:English   Presentation type:Symposium, workshop panel (public)  

    Country:Japan  

  • Design of Heavy Ion Beam Probes on the PLATO tokamak International conference

    Takeshi Ido, Akihide Fujisawa, Keiji Takemura, Naohiro Kasuya, Shigeru Inagaki, Atsushi Fukuyama, Yoshihiko Nagashima, Chanho Moon, Kotaro Yamasaki, Takuma Yamada, Yusuke Kosuga, Makoto Sasaki

    High-Temperature Plasma Diagnostics Conference  2020.12 

     More details

    Event date: 2020.12

    Language:English   Presentation type:Oral presentation (general)  

    Country:Japan  

  • QUEST用重イオンビームプローブの設計

    井戸毅,長谷川真,池添竜也,恩地拓己,出射浩,黒田賢剛,吉田直亮,永島芳彦

    プラズマ・核融合学会  2020.12 

     More details

    Event date: 2020.12

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:オンライン   Country:Japan  

  • 乱流抑制配位創成に向けたHIBP設置可能性の検討

    井戸毅,清水昭博,西浦正樹,濱田泰司,新配位創成研究チーム

    プラズマ・核融合学会  2020.11 

     More details

    Event date: 2020.12

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:オンライン   Country:Japan  

  • LHDにおける高速イオン励起測地線音波バーストが電位分布に及ぼす影響

    井戸毅, 一ノ瀬薫, 清水昭博, 佐々木真, 王 灏, 西浦正樹

    第36回プラズマ・核融合学会年会  2019.11 

     More details

    Event date: 2019.11 - 2019.12

    Language:Japanese   Presentation type:Oral presentation (invited, special)  

    Venue:中部大学   Country:Japan  

    LHDにおいてNBI時に高速イオン励起測地線音波(EGAM)がバースト的に発生する。この時、GAMの周期より十分長く、バースト継続時間より短い時間で平均した平均電位の変動が観測された。電位はプラズマ中心領域で負に、規格化小半径0.2より外では正に変動しており、中心近傍で負電場が形成されている。この電場形成は高速イオンの損失を示唆している。中心近傍においてはEGAM発生時に電位揺動及び密度揺動も減少しており、負電場形成との関連が考えられる。

  • Nonlinear wave-particle interaction in magnetized high temperature plasmas confined in Large Helical Device Invited International conference

    3rd Asia-Pacific Conference on Plasma Physics  2019.11 

     More details

    Event date: 2019.11

    Language:English   Presentation type:Oral presentation (general)  

    Country:China  

  • PLATOトカマクにおける重イオンビームプローブ設置計画

    井戸毅、藤澤彰英、稲垣滋、永島芳彦、文贊鎬、山崎広太郎、糟谷直宏、小菅佑輔、佐々木真、山田琢磨

    日本物理学会  2019.9 

     More details

    Event date: 2019.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:岐阜大学   Country:Japan  

  • Calibration of a Heavy Ion Beam Probe on the PLATO tokamak International conference

    T. Suetsugu, T. Ido, A. Fujisawa, T. Nishizawa, D. Kobayashi, D. Nishimura, C. Moon, Y. Nagashima, N. Kasuya, Y. Kosuga, T. Yamada

    7th Asia-Pacific Conference on Plasma Physics  2023.11 

     More details

    Language:English   Presentation type:Oral presentation (general)  

    Country:Japan  

  • 8p-YM-6 JFT-2Mにおける重イオンビームプローブ計測

    井戸 毅, 西澤 章光, 川澄 義明, 濱田 泰司, 三浦 幸俊

    日本物理学会講演概要集  1997.9 

     More details

    Language:Japanese  

    Country:Japan  

  • 28pUD-2 JFT-2Mトカマクのポテンシャル揺動(28pUD 核融合プラズマ(輸送・閉じ込め特性),領域2(プラズマ基礎・プラズマ科学・核融合プラズマ・プラズマ宇宙物理))

    星野 克道, 永島 芳彦, 井戸 毅, JFT-2Mグループ

    日本物理学会講演概要集  2006.3 

     More details

    Language:Japanese  

    Country:Japan  

  • 27aXE-4 LHDにおける反転磁気シア配位形成時に励起される高速イオン励起アルヴェン固有モードとGAM周波数揺動の空間構造の観測(27aXE 核融合プラズマ(波動・安定性),領域2(プラズマ基礎・プラズマ科学・核融合プラズマ・プラズマ宇宙物理))

    井戸 毅, 清水 昭博, 西浦 正樹, 中野 治久, 加藤 眞治, 東井 和夫, 渡辺 文武, 吉村 泰夫, 久保 伸, 下妻 隆, 伊神 弘恵, 高橋 裕己

    日本物理学会講演概要集  2009.3 

     More details

    Language:Japanese  

    Country:Japan  

  • 金イオンビームとガスターゲットの衝突時の反応断面積測定システムの作製

    谷池 晃, 忍 友彰, 望月 翔, 井戸 毅, 西浦 正樹, 清水 昭博, 古山 雄一, 北村 晃

    神戸大学大学院海事科学研究科紀要  2011.7 

     More details

    Language:Japanese  

    Country:Japan  

  • 26pYG-11 LHDにおける磁場リップルトップ及びボトムECHに対するプラズマの応答(26pYG 核融合プラズマ(電流駆動・波動加熱),領域2(プラズマ基礎・プラズマ科学・核融合プラズマ・プラズマ宇宙物理))

    牧野 良平, 久保 伸, 井戸 毅, 下妻 隆, 吉村 泰夫, 西浦 正樹, 伊神 弘恵, 高橋 裕己, 清水 昭博, 小笠原 慎弥

    日本物理学会講演概要集  2012.3 

     More details

    Language:Japanese  

    Country:Japan  

  • 24aYG-3 LHDプラズマにおける高速イオン励起GAMによる大振幅電位揺動とイオン温度上昇(24aYG 核融合プラズマ(MHD平衡・不安定性・磁気リコネクション,領域2(プラズマ基礎・プラズマ科学・核融合プラズマ・プラズマ宇宙物理)

    東井 和夫, 中村 充希, 井戸 毅, 清水 昭博, 小川 国大, 磯部 光孝, 長壁 正樹, 森田 繁, 後藤 基志, Pablant N. A., LHD実験グループ

    日本物理学会講演概要集  2012.3 

     More details

    Language:Japanese  

    Country:Japan  

  • PLATOトカマクにおける重イオンビームプローブの校正実験

    末継寅英, 井戸毅, 藤澤彰英, 小林大輝, 西村大輝, 清水昭博, 西澤敬之, 永島芳彦, 文贊鎬, 糟谷直宏, 小菅祐輔, 山田琢磨

    プラズマ・核融合学会  2023.11 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:岩手   Country:Japan  

  • QUEST 用重イオンビームプローブのビームラインの設計

    山奥亮汰,井戸毅,末継寅英,長谷川真,木下稔基,河野香,QUEST実験グループ

    プラズマ・核融合学会  2023.11 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:岩手   Country:Japan  

▼display all

MISC

Professional Memberships

  • The Physical Society of Japan

  • The Japan Society of Plasma Science and Nuclear Fusion

  • The Physical Society of Japan

      More details

  • The Japan Society of Plasma Science and Nuclear Fusion

      More details

Committee Memberships

  • プラズマ・核融合学会   編集委員  

    2021.7 - 2023.6   

      More details

    Committee type:Academic society

    researchmap

  • Steering committee member   Domestic

    2013.10 - 2016.9   

  • 日本物理学会   領域2 領域運営委員,役員   Domestic

    2013.10 - 2016.9   

Academic Activities

  • 伊藤賞審査委員 International contribution

    ヨーロッパ物理学会プラズマ物理分科会  ( ボルドー ) 2023.7

     More details

    Type:Competition, symposium, etc. 

  • 伊藤賞審査委員 International contribution

    ヨーロッパ物理学会プラズマ物理分科会  ( オンライン ) 2022.6 - 2022.7

     More details

    Type:Competition, symposium, etc. 

  • Screening of academic papers

    Role(s): Peer review

    2022

     More details

    Type:Peer review 

    Number of peer-reviewed articles in foreign language journals:4

  • プラズマ・核融合学会誌

    2021.7 - 2023.6

     More details

    Type:Academic society, research group, etc. 

  • Screening of academic papers

    Role(s): Peer review

    2021

     More details

    Type:Peer review 

    Number of peer-reviewed articles in foreign language journals:3

    Number of peer-reviewed articles in Japanese journals:0

    Proceedings of International Conference Number of peer-reviewed papers:0

    Proceedings of domestic conference Number of peer-reviewed papers:0

  • プログラム委員,座長 International contribution

    ( リモート会議 ) 2020.10

     More details

    Type:Competition, symposium, etc. 

    Number of participants:550

  • Screening of academic papers

    Role(s): Peer review

    2020

     More details

    Type:Peer review 

    Number of peer-reviewed articles in foreign language journals:5

    Number of peer-reviewed articles in Japanese journals:0

    Proceedings of International Conference Number of peer-reviewed papers:0

    Proceedings of domestic conference Number of peer-reviewed papers:0

  • Screening of academic papers

    Role(s): Peer review

    2019

     More details

    Type:Peer review 

    Number of peer-reviewed articles in foreign language journals:3

    Number of peer-reviewed articles in Japanese journals:0

    Proceedings of International Conference Number of peer-reviewed papers:0

    Proceedings of domestic conference Number of peer-reviewed papers:0

  • Plasma and Fusion Research International contribution

    2018.10 - 2026.9

     More details

    Type:Academic society, research group, etc. 

▼display all

Research Projects

  • QUESTにおける電磁揺動計測に基づく熱・粒子輸送研究の推進

    2024.4 - 2025.3

    共同研究

      More details

    Authorship:Principal investigator  Grant type:Other funds from industry-academia collaboration

  • 磁場閉じ込めプラズマにおける高エネルギー粒子による電位構造形成機構の研究

    2024.4 - 2025.3

    共同研究

      More details

    Authorship:Principal investigator  Grant type:Other funds from industry-academia collaboration

  • 軸対称プラズマの閉じ込め性能のアスペクト比依存性の起源の解明

    Grant number:24K00613  2024 - 2027

    日本学術振興会  科学研究費助成事業  基盤研究(B)

      More details

    Authorship:Principal investigator  Grant type:Scientific research funding

  • Development of a group of particle transport codes connecting the wall, peripheral, and core regions including dependence of ro-vibrational states of molecular hydrogen

    Grant number:23K03362  2023.4 - 2028.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

      More details

    Grant type:Scientific research funding

    CiNii Research

  • Breakthrough of turbulent transport mechanism of self-burning plasma by high energy ion and tubulence analysis

    Grant number:23K25857  2023.4 - 2026.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

      More details

    Grant type:Scientific research funding

    CiNii Research

  • QUESTにおける電磁揺動計測に基づく熱・粒子輸送研究の推進

    2023.4 - 2024.3

    共同研究

      More details

    Authorship:Principal investigator  Grant type:Other funds from industry-academia collaboration

  • LHDプラズマにおける熱・粒子輸送への高速イオン駆動電磁場の影響

    2022.4 - 2023.3

    共同研究

      More details

    Authorship:Principal investigator  Grant type:Other funds from industry-academia collaboration

  • 磁場閉じ込め高温プラズマ内部における2次元電磁揺動計測手法の開発

    2022.4 - 2023.3

    共同研究

      More details

    Authorship:Principal investigator  Grant type:Other funds from industry-academia collaboration

  • LHDプラズマにおける熱・粒子輸送への高速イオン駆動電磁場の影響

    2021.4 - 2022.3

    共同研究

      More details

    Authorship:Principal investigator  Grant type:Other funds from industry-academia collaboration

  • 磁場閉じ込め高温プラズマ内部における2次元電磁揺動計測手法の開発

    2021.4 - 2022.3

    共同研究

      More details

    Authorship:Principal investigator  Grant type:Other funds from industry-academia collaboration

  • QUESTプロジェクト

    2019.10 - 2026.3

    日本 

      More details

    Authorship:Coinvestigator(s) 

  • 高エネルギー粒子駆動揺動場とプラズマ乱流場のスケール間相互作用の検証

    2018 - 2020

    日本学術振興会  科学研究費助成事業  基盤研究(C)

      More details

    Authorship:Principal investigator  Grant type:Scientific research funding

  • PLATOプロジェクト

    2017.4 - 2022.3

    九州大学 

      More details

    Authorship:Coinvestigator(s) 

  • 統合観測システムで解き明かす乱流プラズマの構造形成原理と機能発現機構

    2017 - 2021

    日本学術振興会  科学研究費助成事業  特別推進研究

      More details

    Authorship:Coinvestigator(s)  Grant type:Scientific research funding

  • 微視的乱流と大域的揺らぎの同時計測による磁場閉じ込めプラズマにおける熱輸送の研究

    Grant number:15K06653  2015 - 2017

    日本学術振興会  科学研究費助成事業  基盤研究(C)

      More details

    Authorship:Principal investigator  Grant type:Scientific research funding

  • 高効率多チャンネル重イオン検出器の開発による電場形成とプラズマ乱流の研究

    Grant number:24561031  2012 - 2014

    日本学術振興会  科学研究費助成事業  基盤研究(C)

      More details

    Authorship:Principal investigator  Grant type:Scientific research funding

  • 多チャンネル重イオンビームプローブの開発による電位構造形成過程の研究

    Grant number:20686062  2008 - 2010

    科学研究費助成事業  若手研究(A,B)

      More details

    Authorship:Principal investigator  Grant type:Scientific research funding

  • 高エネルギー粒子駆動揺動場とプラズマ乱流場のスケール間相互作用の検証

    Grant number:18K03589 

    井戸 毅, 清水 昭博, 谷池 晃

      More details

    Grant type:Scientific research funding

    磁場閉じ込めプラズマの閉じ込め性能を左右する電位や密度の揺らぎを計測するための計測器であるHIBPの高精度化を行い、これを用いてプラズマ中の高速イオンによって励起される不安定性とプラズマ乱流の計測に成功した。高速イオン励起不安定性とプラズマ乱流の直接相互作用は観測されなかったが、これまで観測されたことのない、高速イオン励起不安定性の2次元構造や高速イオンによる電場形成など新しい現象を見出すことに成功した。

    CiNii Research

  • 統合観測システムで解き明かす乱流プラズマの構造形成原理と機能発現機構

    Grant number:17H06089 

    藤澤 彰英, 井戸 毅, 稲垣 滋, 飯尾 俊二

      More details

    Grant type:Scientific research funding

    変容する自然の理解および核融合炉実現のための磁場閉じ込めプラズマの学術体系化を目指した乱流プラズマの統合大域精密観測装置PLATOが完成し運転を開始している。その建設過程において装置電源としての誘導型フライホイールほか1000チャンネルを超えるトモグラフィーデータ記録装置などの経済的技術も生まれている。PLATOプロジェクトを支援する研究としての直線プラズマ装置PANTAにおいては準3次元トモグラフィーが完成しそのための画像解析法(Fourier-Rectangular級数展開法など)も開発された。理論シミュレーショ研究では、広く乱流プラズマに関連した成果が多数上がっている。

    CiNii Research

▼display all

Class subject

  • 物理概論

    2024.4 - 2024.9   First semester

  • 物理概論

    2023.4 - 2023.9   First semester

  • 総合理工学修士演習

    2022.4 - 2023.3   Full year

  • 総合理工学修士実験

    2022.4 - 2023.3   Full year

  • 物理概論

    2022.4 - 2022.9   First semester

  • 物理概論

    2021.4 - 2021.9   First semester

  • 物理数学基礎

    2020.4 - 2020.6   Spring quarter

▼display all

Activities contributing to policy formation, academic promotion, etc.

  • 2021.4 - 2022.3   プラズマ・核融合学会

    プラズマ・核融合学会専門委員会「データサイエンスとの連携によるプラズマ・核融合データ利活用の推進」