2025/06/20 更新

お知らせ

 

写真a

イサヤマ シヨウゴ
諌山 翔伍
ISAYAMA SHOGO
所属
総合理工学研究院 環境理工学部門 助教
総合理工学府 総合理工学専攻(併任)
工学部 融合基礎工学科(併任)
職名
助教
連絡先
メールアドレス
電話番号
0925838602
プロフィール
高周波プラズマ源、レーザーによる粒子加速、高エネルギー宇宙物理に関する理論、数値計算、実験を用いた研究を専門とする。
外部リンク

研究分野

  • 自然科学一般 / 素粒子、原子核、宇宙線、宇宙物理にする実験

学位

  • 理学博士

経歴

  • 九州大学 環境理工学部門 流体環境科学講座 宇宙流体環境学分野 助教 

    2020年4月 - 現在

学歴

  • 台湾国立中央大学      物理学科

    2017年5月 - 2020年3月

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    国名:台湾

    備考:博士研究員

  • 九州大学   大気環境システム学専攻博士課程  

    2012年4月 - 2017年3月

  • 九州大学   大気環境システム学専攻修士課程  

    2010年4月 - 2012年3月

  • 九州大学   工学部   機械航空工学科

    2006年4月 - 2010年3月

研究テーマ・研究キーワード

  • 研究テーマ: 高出力レーザーを用いた無衝突衝撃波に関する実験的研究

    研究キーワード: 実験室宇宙物理、無衝突衝撃波、高出力レーザー

    研究期間: 2020年7月 - 2020年8月

  • 研究テーマ: レーザー船跡場加速への相対論的イオン注入制御に関する研究

    研究キーワード: レーザーイオン加速、レーザー船跡場加速

    研究期間: 2017年5月 - 2020年8月

  • 研究テーマ: 高密度ヘリコンプラズマ生成の時空間発展に関する研究

    研究キーワード: 高周波プラズマ源、ヘリコンプラズマ

    研究期間: 2010年4月 - 2020年8月

受賞

  • 第26回論文賞

    2018年12月   プラズマ・核融合学会  

論文

  • Acceleration of Relativistic Particles in Counterpropagating Circularly Polarized Alfvén Waves 招待 査読 国際誌

    Isayama, S; Takahashi, K; Matsukiyo, S; Sano, T

    ASTROPHYSICAL JOURNAL   946 ( 2 )   68   2023年3月   ISSN:0004-637X eISSN:1538-4357

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    記述言語:英語   出版者・発行元:Astrophysical Journal  

    Counterpropagating Alfvén waves are ubiquitously observed in many astrophysical environments, such as a star surface and a planetary foreshock. We discuss an efficient particle acceleration mechanism in two counterpropagating circularly polarized Alfvén waves. Phase transitions of particle behavior occur when wave amplitudes exceed two critical values. Above the critical amplitudes, the numerical simulation shows that any particles irreversibly gain relativistic energy within a short time regardless of their initial position and energy once the coherent waveform is formed. The accelerated particles have spatial coherence. Higher wave phase velocity requires smaller critical amplitudes, while the maximum attainable energy increases as the wavenumber and the frequency decrease. The results may be applicable in some astrophysical phenomena, as well as a future laboratory experiment using high-power lasers.

    DOI: 10.3847/1538-4357/acbb6d

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  • Ion-acoustic feature of collective Thomson scattering in non-equilibrium two-stream plasmas 招待 査読 国際誌

    Sakai, K., Nishimoto, T., Isayama, S., Matsukiyo, S. & Kuramitsu, Y.

    Physics of Plasmas   30 ( 1 )   012105   2023年1月

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    記述言語:英語  

  • Ion-acoustic feature of collective Thomson scattering in non-equilibrium two-stream plasmas 招待 査読 国際誌

    Sakai, K., Nishimoto, T., Isayama, S., Matsukiyo, S. & Kuramitsu, Y.

    Physics of Plasmas   30 ( 1 )   012105   2023年1月

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    記述言語:英語  

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  • Mass-resolved ion measurement by particle counting analysis for characterizing relativistic ion beams driven by lasers 招待 査読 国際誌

    Minami, T; Tokiyasu, AO; Kohri, H; Abe, Y; Iwasaki, K; Taguchi, T; Oda, K; Suzuki, S; Asai, T; Tanaka, SJ; Isayama, S; Kanasaki, M; Kodaira, S; Fukuda, Y; Kuramitsu, Y

    REVIEW OF SCIENTIFIC INSTRUMENTS   93 ( 11 )   113530   2022年9月   ISSN:0034-6748 eISSN:1089-7623

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    記述言語:英語   出版者・発行元:Review of Scientific Instruments  

    Particle counting analysis is a possible way to characterize GeV-scale, multi-species ions produced in laser-driven experiments. We present a multi-layered scintillation detector to differentiate multi-species ions of different masses and energies. The proposed detector concept offers potential advantages over conventional diagnostics in terms of (1) high sensitivity to GeV ions, (2) realtime analysis, and (3) the ability to differentiate ions with the same charge-to-mass ratio. A novel choice of multiple scintillators with different ion stopping powers results in a significant difference in energy deposition between the scintillators, allowing accurate particle identification in the GeV range. Here, we report a successful demonstration of particle identification for heavy ions, performed at the Heavy Ion Medical Accelerator in Chiba. In the experiment, the proposed detector setup showed the ability to differentiate particles with similar atomic numbers, such as C6+ and O8+ ions, and provided an excellent energy resolution of 0.41%-1.2% (including relativistic effect, 0.51% - 1.6%).

    DOI: 10.1063/5.0101872

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  • Robustness of large-area suspended graphene under interaction with intense laser 招待 査読 国際誌

    Kuramitsu Y., Minami, T., Hihara T., Sakai K., Nishimoto T., Isayama S., Liao Y. T., Wu K. T., Woon W. Y., Chen S. H., Liu Y. L., He S. M., Su C. Y., Ota M., Egashira S., Morace A., Sakawa Y., Abe Y., Habara H., Kodama R., Döhl L. N. K., Woolsey N., Koenig M., Kumar H. S., Ohnishi N., Kanasaki M., Asai T., Yamauchi T., Oda K., Kondo Ko., Kiriyama H., Fukuda, Y.

    SCIENTIFIC REPORTS   12 ( 1 )   2346   2022年2月   ISSN:2045-2322

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    記述言語:英語   出版者・発行元:Scientific Reports  

    Graphene is known as an atomically thin, transparent, highly electrically and thermally conductive, light-weight, and the strongest 2D material. We investigate disruptive application of graphene as a target of laser-driven ion acceleration. We develop large-area suspended graphene (LSG) and by transferring graphene layer by layer we control the thickness with precision down to a single atomic layer. Direct irradiations of the LSG targets generate MeV protons and carbons from sub-relativistic to relativistic laser intensities from low contrast to high contrast conditions without plasma mirror, evidently showing the durability of graphene.

    DOI: 10.1038/s41598-022-06055-4

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  • Efficient hybrid acceleration scheme for generating 100 MeV protons with tabletop dual-laser pulses 査読 国際誌

    S. Isayama, S. H. Chen2, Y. L. Liu, H. W. Chen and Y. Kuramitsu

    Physics of Plasmas   28   073101   2021年6月

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    記述言語:英語  

    DOI: 10.1063/5.0049725

  • Collective Thomson scattering in non-equilibrium laser produced two-stream plasmas 査読 国際誌

    Sakai, K., Isayama, S., Bolouki, N., Habibi, M. S., Liu, Y. L., Hsieh, Y. H., Chu, H. H., Wang, J., Chen, S. H., Morita, T., Tomita, K., Yamazaki, R., Sakawa, Y., Matsukiyo, S. & Kuramitsu, Y.

    Physics of Plasmas   27 ( 10 )   103104   2020年10月

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    記述言語:英語  

    DOI: 10.1063/5.0011935

  • Collective Thomson scattering measurements of electron feature using stimulated Brillouin scattering in laser-produced plasmas 査読 国際誌

    N. Bolouki, K. Sakai, T. Y. Huang, S. Isayama, Y. L. Liu, C. W. Peng, C. H. Chen, N. Khasanah, H. H. Chu, T. Moritaka, K. Tomita, Y. Sato, K. Uchino, T. Morita, S. Matsukiyo, Y. Hara, H. Shimogawara, Y Sakawa, S. Sakata, S. Kojima, S. Fujioka, Y. Shoji, S. Tomiya, R. Yamazaki, M. Koenig, Y. Kuramitsu

    High Energy Density Physics   32   82   2019年7月

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    記述言語:英語  

  • Spatio-temporal behavior of density jumps and the effect of neutral depletion in high-density helicon plasma. 査読 国際誌

    S. Isayama, S. Shinohara, T. Hada, S. H. Chen

    Physics of Plasmas   26   053504   2019年4月

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    記述言語:英語  

  • Nonthermal relativistic electron acceleration due to laser-induced incoherent wakefields with external static magnetic fields. 査読 国際誌

    Y. L. Liu, S. H. Chen, S. Isayama, and Y. Kuramitsu

    High Energy Density Physics   31   64   2019年3月

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    記述言語:英語  

  • Underlying competition mechanisms in the dynamic profile formation of high-density helicon plasma. 査読 国際誌

    S. Isayama, S. Shinohara, T. Hada, and S. H. Chen

    Physics of Plasmas   26   023517   2019年2月

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    記述言語:英語  

  • Review of Helicon High-Density Plasma: Production Mechanism and Plasma/Wave Characteristics. Plasma and Fusion Research 査読 国際誌

    S. Isayama, S. Shinohara, and T. Hada

    Plasma and Fusion Research   13   1101014   2018年2月

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    記述言語:英語  

  • Radiation pressure injection in laser-wakefield acceleration. 査読 国際誌

    Y. L. Liu, Y. Kuramitsu, S. Isayama, and S. H. Chen

    Physics of Plasmas   25   013110   2018年1月

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    記述言語:英語  

  • Spherical shock in the presence of an external magnetic field. 査読 国際誌

    Y Kuramitsu, S Matsukiyo, S Isayama, D Harada, T Oyama, R Fujino, Y Sakawa, T Morita, Y Yamaura, T Ishikawa, T Moritaka, T Sano, K Tomita, R Shimoda, Y Sato, K Uchino, A Pelka, R Crowston, N Woolsey, G Gregori, M Koenig, D W Yuan, C L Yin, Y T Li, K Zhang, J Y Zhong, F L Wang, N Ohnishi, K Nagamine, H Yoneda, and H Takabe.

    Journal of Physics: Conference Series   688   012056   2016年11月

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    記述言語:英語  

  • Is the bulk mode conversion important in high density helicon plasma? 査読 国際誌

    S. Isayama, T. Hada, S. Shinohara and T. Tanikawa

    Physics of Plasmas   23   063513   2016年6月

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    記述言語:英語  

  • Ion acceleration with an intense short-pulse laser and large-area suspended graphene in an extremely thin target regime

    Minami, T; Chu, C; Mccusker, O; Sakai, K; Liao, Y; Tamaki, N; Kondo, K; Kiriyama, H; Egashira, S; Ota, M; Morace, A; Sakawa, Y; Alkhimova, M; Pikuz, T; Nikaido, F; Yasui, T; Suzuki, S; Abe, Y; Habara, H; Kumar, HS; Isayama, S; Jao, C; Wu, K; Liul, YL; Mcilvenny, A; Borghesi, M; Jinno, S; Kanasaki, M; Fukuda, Y; Woon, WY; Kuramitsu, Y

    HIGH ENERGY DENSITY PHYSICS   55   2025年6月   ISSN:1574-1818 eISSN:1878-0563

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    出版者・発行元:High Energy Density Physics  

    Graphene is an atomic thin 2D material, known as the strongest material with such a thin regime. Free-standing, large-area suspended graphene (LSG) has been developed for a target of laser-driven ion acceleration. The LSG has shown remarkable durability against laser prepulse, producing MeV protons and carbons by direct irradiation with an intense laser without a plasma mirror, yet no optimization has been concerned. Here we investigate the optimization of the laser-driven ion acceleration with LSG, paying special attention to the target conditions. We irradiate nanometer-thick LSG with an intense laser, where the incident angle and the target thickness are controlled. The maximum proton energy increases with increasing the number of LSG layers, where 25±0.3MeV protons at maximum are consistently observed with Thomson parabola spectrometer and diamond-based detectors. For comparison purposes, we perform ideal numerical simulations using particle-in-cell (PIC) code without consideration of the prepulse. In the PIC simulation, the protons are successively accelerated by the electric field associated with laser radiation pressure and the surface sheath field, yet the maximum proton energies are overestimated. The maximum proton energies from the experiment asymptotically approach the ideal PIC expectations, indicating that the thinner LSG is more affected by the prepulse. We expect higher proton energy with the optimized LSG conditions and a plasma mirror.

    DOI: 10.1016/j.hedp.2025.101195

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  • Electron Density Structure Measurements With Scattered Intense Laser Beam

    Sakai, K; Himeno, K; Tanaka, SJ; Asai, T; Minami, T; Abe, Y; Nikaido, F; Kuramoto, K; Kanasaki, M; Kiriyama, H; Kon, A; Kondo, K; Nakanii, N; Woon, WY; Chu, CM; Wu, KT; Jao, CS; Liu, YL; Pikuz, TA; Kohri, H; Tokiyasu, AO; Isayama, S; Kumar, HS; Tomita, K; Fukuda, Y; Kuramitsu, Y

    CONTRIBUTIONS TO PLASMA PHYSICS   2025年5月   ISSN:0863-1042 eISSN:1521-3986

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    出版者・発行元:Contributions to Plasma Physics  

    Short-pulse intense lasers have the potential to model extreme astrophysical environments in laboratories. Although there are diagnostics for energetic electrons and ions resulting from laser-plasma interactions, the diagnostics to measure velocity distribution functions at the interaction region of the laser and plasma are limited. We have been developing the diagnostics of the interaction between the intense laser and plasma using scattered intense laser. We performed experiments to measure electron density by observing the spatial distributions and the ratio of horizontal to vertical polarization components of the scattered laser beam using optical imaging. The observed ratio of polarization components is consistent with the drive laser beam, indicating the observed light originates from the drive laser. Imaging of the scattered light shows the structure of electron density, the zero moment of the electron velocity distribution function, interacting with the intense laser. We observed the change of structure due to the laser pre-pulse that destroys the target before the arrival of the main pulse.

    DOI: 10.1002/ctpp.70020

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  • Relativistic two-wave resonant acceleration of electrons at large-amplitude standing whistler waves during laser-plasma interaction

    Sano, T; Isayama, S; Takahashi, K; Matsukiyo, S

    PHYSICAL REVIEW E   110 ( 6 )   065212   2024年12月   ISSN:2470-0045 eISSN:2470-0053

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    記述言語:英語   出版者・発行元:Physical Review E  

    The interaction between a thin foil target and a circularly polarized laser light injected along an external magnetic field is investigated numerically by particle-in-cell simulations. A standing wave appears at the front surface of the target, overlapping the injected and partially reflected waves. Hot electrons are efficiently generated at the standing wave due to the relativistic two-wave resonant acceleration if the magnetic field amplitude of the standing wave is larger than the ambient field. A bifurcation occurs in the gyration motion of electrons, allowing all electrons with nonrelativistic velocities to acquire relativistic energy through the cyclotron resonance. The optimal conditions for the highest energy and the most significant fraction of hot electrons are derived precisely through a simple analysis of test-particle trajectories in the standing wave. Since the number of hot electrons increases drastically by many orders of magnitude compared to the conventional unmagnetized cases, this acceleration could be a great advantage in laser-driven ion acceleration and its applications.

    DOI: 10.1103/PhysRevE.110.065212

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  • Mechanism of generating collisionless shock in magnetized gas plasma driven by laser-ablated target plasma

    Matsukiyo, S; Oshida, K; Isayama, S; Yamazaki, R; Morita, T; Takezaki, T; Kuramitsu, Y; Tanaka, SJ; Sano, T; Tomita, K; Sakawa, Y

    PHYSICS OF PLASMAS   31 ( 11 )   2024年11月   ISSN:1070-664X eISSN:1089-7674

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    出版者・発行元:Physics of Plasmas  

    The mechanism of generating collisionless shock in magnetized gas plasma driven by laser-ablated target plasma is investigated by using one-dimensional full particle-in-cell simulation. The effect of finite injection time of target plasma, mimicking the finite width of laser pulse, is taken into account. It was found that the formation of a seed-shock requires a precursor. The precursor is driven by gyrating ions, and its origin varies depending on the injection time of the target plasma. When the injection time is short, the target plasma entering the gas plasma creates a precursor; otherwise, gas ions reflected by the strong piston effect of the target plasma create a precursor. The precursor compresses the background gas plasma, and subsequently, a compressed seed-shock forms in the gas plasma. The parameter dependence on the formation process and propagation characteristics of the seed-shock was discussed. It was confirmed that the seed-shock propagates through the gas plasma exhibiting behavior similar to the shock front of supercritical shocks.

    DOI: 10.1063/5.0230232

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  • Research progress and remarks on helicon plasma: a report on the Second Helicon Plasma Physics and Applications Workshop

    Chang, L; Boswell, R; Scime, E; Shinohara, S; Takahashi, K; Thakur, S; Filleul, F; Caldarelli, A; Isayama, S; Yu, Y; Xu, M; Zhang, HB; Huang, TY; Wu, MY; Wu, JT; Xia, BH; Lu, LF; Sun, AP; Du, D; Zhang, ZY; Yuan, RX; Xu, AD; Yang, X; Jing, D; Xia, Y; Wang, C; Zhang, YW; Wu, XS; Yang, ZY; Sun, YZ

    REVIEWS OF MODERN PLASMA PHYSICS   8 ( 1 )   2024年10月   ISSN:2367-3192

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    出版者・発行元:Reviews of Modern Plasma Physics  

    Following the First Helicon Plasma Physics and Applications (HPPA) Workshop, which was held in 2021 remotely due to COVID-19, this Second HPPA Workshop aimed to establish a regular onsite meeting for the specific field of helicon plasma. It was held on 11–14 April 2024 in Chongqing, China, and organized by Chongqing University and co-organized by Southwestern Institute of Physics. This workshop attracted ~ 160 registrations, ~ 140 onsite participants, and ~ 27,000 number of views through the live streaming online. The 48 presentations covered most topics about helicon plasma, e.g., from fundamental physics to various applications. This paper summarizes the important findings of fundamental physics research, progresses on source and diagnostic developments, and new explorations of laboratory and industrial applications, together with enlightening comments and perspectives regarding future research for this field. It serves as a valuable reference for the helicon research community and other relevant fields.

    DOI: 10.1007/s41614-024-00171-6

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  • Optimization of laser-driven quantum beam generation and the applications with artificial intelligence

    Kuramitsu, Y; Taguchi, T; Nikaido, F; Minami, T; Hihara, T; Suzuki, S; Oda, K; Kuramoto, K; Yasui, T; Abe, Y; Ibano, K; Takabe, H; Chu, CM; Wu, KT; Woon, WY; Chen, SH; Jao, CS; Chen, YC; Liu, YL; Morace, A; Yogo, A; Arikawa, Y; Kohri, H; Tokiyasu, A; Kodaira, S; Kusumoto, T; Kanasaki, M; Asai, T; Fukuda, Y; Kondo, K; Kiriyama, H; Hayakawa, T; Tanaka, SJ; Isayama, S; Watamura, N; Suzuki, H; Kumar, HS; Ohnishi, N; Pikuz, T; Filippov, E; Sakai, K; Yasuhara, R; Nakata, M; Ishikawa, R; Hoshi, T; Mizuta, A; Bolouki, N; Saura, N; Benkadda, S; Koenig, M; Hamaguchi, S

    PHYSICS OF PLASMAS   31 ( 5 )   2024年5月   ISSN:1070-664X eISSN:1089-7674

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    出版者・発行元:Physics of Plasmas  

    We have investigated space and astrophysical phenomena in nonrelativistic laboratory plasmas with long high-power lasers, such as collisionless shocks and magnetic reconnections, and have been exploring relativistic regimes with intense short pulse lasers, such as energetic ion acceleration using large-area suspended graphene. Increasing the intensity and repetition rate of the intense lasers, we have to handle large amounts of data from the experiments as well as the control parameters of laser beamlines. Artificial intelligence (AI) such as machine learning and neural networks may play essential roles in optimizing the laser and target conditions for efficient laser ion acceleration. Implementing AI into the laser system in mind, as the first step, we are introducing machine learning in ion etch pit analyses detected on plastic nuclear track detectors. Convolutional neural networks allow us to analyze big ion etch pit data with high precision and recall. We introduce one of the applications of laser-driven ion beams using AI to reconstruct vector electric and magnetic fields in laser-produced turbulent plasmas in three dimensions.

    DOI: 10.1063/5.0190062

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  • Advancements in neural network techniques for electric and magnetic field reconstruction: Application to ion radiography

    Jao, CS; Chen, YC; Nikaido, F; Liu, YL; Sakai, K; Minami, T; Isayama, S; Abe, Y; Kuramitsu, Y

    AIP ADVANCES   14 ( 2 )   2024年2月   eISSN:2158-3226

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    出版者・発行元:AIP Advances  

    In the realm of high-energy-density laboratory plasma experiments, ion radiography is a vital tool for measuring electromagnetic fields. Leveraging the deflection of injected protons, ion imaging can reveal the intricate patterns of electromagnetic fields within the plasma. However, the complex task of reconstructing electromagnetic fields within the plasma system from ion images presents a formidable challenge. In response, we propose the application of neural network techniques to facilitate electromagnetic field reconstructions. For the training data, we generate corresponding particle data on ion radiography with diverse field profiles in the plasma system, drawing from analytical solutions of charged particle motions and test-particle simulations. With these training data, our expectation is that the developed neural network can assimilate information from ion radiography and accurately predict the corresponding field profiles. In this study, our primary emphasis is on developing these techniques within the context of the simplest setups, specifically uniform (single-layer) or two-layer systems. We begin by examining systems with only electric or magnetic fields and subsequently extend our exploration to systems with combined electromagnetic fields. Our findings demonstrate the viability of employing neural networks for electromagnetic field reconstructions. In all the presented scenarios, the correlation coefficients between the actual and neural network-predicted values consistently reach 0.99. We have also learned that physics concepts can help us understand the weaknesses in neural network performance and identify directions for improvement.

    DOI: 10.1063/5.0189878

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  • Advancements in neural network techniques for electric and magnetic field reconstruction: Application to ion radiography 招待 査読 国際誌

    Jao, C. S., Chen, Y. C., Nikaido, F., Liu, Y. L., Sakai, K., Minami, T., Isayama, S., Abe, Y. & Kuramitsu, Y.

    AIP Advances.   14 ( 2 )   025037   2024年2月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

  • Deep learning approaches for modeling laser-driven proton beams via phase-stable acceleration 招待 査読 国際誌

    Liu, Y. L., Chen, Y. C., Jao, C. S., Wong, M. S., Huang, C. H., Chen, H. W., Isayama, S. & Kuramitsu, Y.

    Physics of Plasmas.   31 ( 1 )   013106   2024年1月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

  • Deep learning approaches for modeling laser-driven proton beams via phase-stable acceleration

    Liu, YL; Chen, YC; Jao, CS; Wong, MS; Huang, CH; Chen, HW; Isayama, S; Kuramitsu, Y

    PHYSICS OF PLASMAS   31 ( 1 )   2024年1月   ISSN:1070-664X eISSN:1089-7674

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    出版者・発行元:Physics of Plasmas  

    Deep learning (DL) has recently become a powerful tool for optimizing parameters and predicting phenomena to boost laser-driven ion acceleration. We developed a neural network surrogate model using an ensemble of 355 one-dimensional particle-in-cell simulations to validate the theory of phase-stable acceleration (PSA) driven by a circularly polarized laser driver. Our DL predictions confirm the PSA theory and reveal a discrepancy in the required target density for stable ion acceleration at larger target thicknesses. We discuss the physical reasons behind this density underestimation based on our DL insights.

    DOI: 10.1063/5.0178238

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  • Ion-acoustic feature of collective Thomson scattering in non-equilibrium two-stream plasmas

    Sakai, K; Nishimoto, T; Isayama, S; Matsukiyo, S; Kuramitsu, Y

    PHYSICS OF PLASMAS   30 ( 1 )   2023年1月   ISSN:1070-664X eISSN:1089-7674

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    出版者・発行元:Physics of Plasmas  

    We theoretically and numerically investigate the ion-acoustic features of collective Thomson scattering (CTS) in two-stream plasmas. When the electron distribution functions of two (stationary and moving) components overlap with each other at the phase velocities corresponding to the two resonant peaks of the ion-acoustic feature, the theoretical spectrum shows asymmetry because the rate of electron Landau damping is different for the two peaks. The results of numerical simulations agree well with the theoretical spectra. We also demonstrate the effect of a two-stream-type instability in the ion-acoustic feature. The simulated spectrum in the presence of the instability shows an asymmetry with the opposite trend to the overlapped case, which results from the temporal change of the electron distribution function caused by the instability. Our results show that two-stream plasmas have significant effects on CTS spectra and that the waves resulting from instabilities can be observed in the ion-acoustic feature.

    DOI: 10.1063/5.0117812

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  • Detection of current-sheet and bipolar ion flows in a self-generated antiparallel magnetic field of laser-produced plasmas for magnetic reconnection research

    Morita, T; Kojima, T; Matsuo, S; Matsukiyo, S; Isayama, S; Yamazaki, R; Tanaka, SJ; Aihara, K; Sato, Y; Shiota, J; Pan, Y; Tomita, K; Takezaki, T; Kuramitsu, Y; Sakai, K; Egashira, S; Ishihara, H; Kuramoto, O; Matsumoto, Y; Maeda, K; Sakawa, Y

    PHYSICAL REVIEW E   106 ( 5 )   055207   2022年11月   ISSN:2470-0045 eISSN:2470-0053

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    記述言語:英語   出版者・発行元:Physical Review E  

    Magnetic reconnection in laser-produced magnetized plasma is investigated by using optical diagnostics. The magnetic field is generated via the Biermann battery effect, and the inversely directed magnetic field lines interact with each other. It is shown by self-emission measurement that two colliding plasmas stagnate on a midplane, forming two planar dense regions, and that they interact later in time. Laser Thomson scattering spectra are distorted in the direction of the self-generated magnetic field, indicating asymmetric ion velocity distribution and plasma acceleration. In addition, the spectra perpendicular to the magnetic field show different peak intensity, suggesting an electron current formation. These results are interpreted as magnetic field dissipation, reconnection, and outflow acceleration. Two-directional laser Thomson scattering is, as discussed here, a powerful tool for the investigation of microphysics in the reconnection region.

    DOI: 10.1103/PhysRevE.106.055207

    Web of Science

    Scopus

    PubMed

  • High-power laser experiment on developing supercritical shock propagating in homogeneously magnetized plasma of ambient gas origin

    Matsukiyo, S; Yamazaki, R; Morita, T; Tomita, K; Kuramitsu, Y; Sano, T; Tanaka, SJ; Takezaki, T; Isayama, S; Higuchi, T; Murakami, H; Horie, Y; Katsuki, N; Hatsuyama, R; Edamoto, M; Nishioka, H; Takagi, M; Kojima, T; Tomita, S; Ishizaka, N; Kakuchi, S; Sei, S; Sugiyama, K; Aihara, K; Kambayashi, S; Ota, M; Egashira, S; Izumi, T; Minami, T; Nakagawa, Y; Sakai, K; Iwamoto, M; Ozaki, N; Sakawa, Y

    PHYSICAL REVIEW E   106 ( 2 )   025205   2022年8月   ISSN:2470-0045 eISSN:2470-0053

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    記述言語:英語   出版者・発行元:Physical Review E  

    A developing supercritical collisionless shock propagating in a homogeneously magnetized plasma of ambient gas origin having higher uniformity than the previous experiments is formed by using high-power laser experiment. The ambient plasma is not contaminated by the plasma produced in the early time after the laser shot. While the observed developing shock does not have stationary downstream structure, it possesses some characteristics of a magnetized supercritical shock, which are supported by a one-dimensional full particle-in-cell simulation taking the effect of finite time of laser-Target interaction into account.

    DOI: 10.1103/PhysRevE.106.025205

    Web of Science

    Scopus

    PubMed

▼全件表示

講演・口頭発表等

  • Neutral depletion and the density limit of the helicon plasma

    S. Isayama, S. Shinohara, T. Hada

    Japan Geoscience Union Meeting (日本地球惑星科学連合) 2021  2021年5月 

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    開催年月日: 2021年7月

    記述言語:日本語   会議種別:口頭発表(一般)  

    開催地:e-conference   国名:日本国  

  • Dynamic profile formation of the helicon discharge 招待 国際会議

    S. Isayama, S. Shinohara, T. Hada, S. H. Chen.

    4th Asia-Pacific Conference on Plasma Physics (AAPPS-DPP2020)  2020年10月 

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    開催年月日: 2021年7月

    記述言語:英語   会議種別:口頭発表(一般)  

    開催地:e-conference   国名:その他  

  • Controlled injection of relativistic protons in wakefield by using dual-laser pulses 招待 国際会議

    S. Isayama, S. H. Chen, H. W. Chen, Y. L. Liu, Y. Kuramitsu, Y. Fukuda

    International Conference on High Energy Density Sciences (HEDS-2021)  2021年4月 

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    開催年月日: 2021年7月

    記述言語:英語   会議種別:口頭発表(一般)  

    開催地:Osaka(e-conference)   国名:日本国  

  • Dynamic profile formation in the high-density helicon plasma

    S. Isayama, S. Shinohara, T. Hada, S. H. Chen

    第148回 地球電磁気・地球惑星圏学会  2020年11月 

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    開催年月日: 2021年7月

    記述言語:日本語   会議種別:口頭発表(一般)  

    開催地:e-conference   国名:日本国  

  • Underlying mechanims in the dynamic profile formation of high-density helicon plasma

    S. Isayama, S. Shinohara, T. Hada and S. H. Chen

    3rd Asia-Pacific Conference on Plasma Physics (AAPPS-DPP2019)  2019年11月 

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    開催年月日: 2018年11月

    記述言語:日本語  

    国名:中華人民共和国  

  • Ion accelration using self-focusing laser pulse in near critical density plasma 招待 国際会議

    S. Isayama, S. H. Chen, Y. Kuramitsu and Y. Fukuda

    2nd Asia-Pacific Conference on Plasma Physics (AAPPS-DPP2018)  2018年11月 

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    開催年月日: 2018年11月

    記述言語:英語  

    国名:日本国  

  • Laser-driven accelration with ultra-thin graphene target 国際会議

    S. Isayama, S. H. Chen, H. H. Chu and Y. Kuramitsu

    12th International Conference on High Energy Density Laboratory Astrophysics  2018年5月 

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    開催年月日: 2018年5月

    記述言語:英語  

    国名:日本国  

  • Self-consistent model of the helicon discharge 招待

    S. Isayama, T. Hada and S. Shinohara

    2nd Asia-Pacific Conference on Plasma Physics (AAPPS-DPP2017)  2017年9月 

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    開催年月日: 2017年9月

    記述言語:英語  

    国名:中華人民共和国  

  • Simulation Study of Tabletop Two-stage Laser Proton Acceration 国際会議

    S. Isayama, S. H. Chen, Y. L. Liu and Y. Kuramitsu

    2020台湾物理学会  2020年1月 

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    開催年月日: 2020年1月

    記述言語:英語  

    国名:台湾  

  • Exploration for highly efficient laserdriven acceleration 国際会議

    S. Isayama, S. H. Chen, Y. L. Liu, and Y. Kuramitsu

    2019台湾物理学会  2019年1月 

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    開催年月日: 2019年1月

    記述言語:英語  

    国名:台湾  

  • Review of Helicon High-Density Plasma: Production Mechanism and Plasma/Wave Characteristics

    諌山 翔伍, 篠原 俊二郎, 羽田 亨

    第35回 プラズマ・核融合学会  2018年12月 

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    開催年月日: 2018年12月

    記述言語:日本語  

    開催地:大阪   国名:日本国  

  • Mechanism of the helicon plasma production 国際会議

    S. Isayama, T. Hada, S. Shinohara and S. H. Chen

    2018台湾物理学会  2018年1月 

     詳細を見る

    開催年月日: 2018年1月

    記述言語:英語  

    国名:台湾  

▼全件表示

MISC

  • 対向伝搬する磁気流体波動による相対論的共鳴粒子加速

    諌山翔伍, 高橋健太, 松清修一, 佐野孝好

    2023年5月

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    記述言語:日本語   出版者・発行元:プラズマ核融合学会  

    researchmap

  • ヘリコンプラズマ源の基礎と応用 査読

    諌山 翔伍、篠原 俊二郎、桑原 大介、高橋 和貴,古川 武留、稲垣 滋

    プラズマ・核融合学会誌   2023年10月

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

所属学協会

  • プラズマ・核融合学会

  • 地球電磁気・地球惑星圏学会

  • 日本物理学会

  • 日本物理学会

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  • 地球電磁気・地球惑星圏学会

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  • プラズマ・核融合学会

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学術貢献活動

  • 学術論文等の審査

    役割:査読

    2022年

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    種別:査読等 

  • プラズマ・核融合学会

    2021年7月 - 2023年7月

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    種別:学会・研究会等 

  • プラズマ・核融合学会

    役割:審査・評価

    2021年7月 - 2023年7月

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    種別:査読等 

    researchmap

共同研究・競争的資金等の研究課題

  • 相対論プラズマ中でのレーザー航跡場イオン加速の学理探求とその実証

    研究課題/領域番号:25H00622  2025年4月 - 2029年3月

    日本学術振興会  基盤研究A 

    諌山 翔伍

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    担当区分:研究分担者  資金種別:科研費

  • 高強度レーザーを用いた高エネルギー宇宙線加速機構の解明

    研究課題/領域番号:OML012508  2025年4月 - 2026年3月

    自然科学研究機構  OPEN MIX LAB (OML)公募研究プログラム(研究共創型) 

    諌山 翔伍

      詳細を見る

    担当区分:研究代表者 

  • 大振幅な磁気流体波動による高エネルギー宇宙線生成機構の解明

    研究課題/領域番号:25K00221  2025年2月 - 2028年3月

    科学研究費助成事業  基盤研究(C)

    諌山 翔伍

      詳細を見る

    資金種別:科研費

    CiNii Research

  • 大振幅アルフベン波による粒子加速の多次元計算

    研究課題/領域番号:R7-KDK-20  2025年4月 - 2026年3月

    京都大学  京都大学電波科学計算機実験装置(KDK)共同利用・共同研究 

    諌山 翔伍

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    担当区分:研究代表者 

  • 数値計算による中性粒子枯渇現象の密度限界・密度振動への影響の解明

    研究課題/領域番号:22K14020  2022年 - 2024年

    日本学術振興会  科学研究費助成事業  若手研究

    諌山 翔伍

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    担当区分:研究代表者  資金種別:科研費

    高パワー・高密度な高周波プラズマ源において、イオン化の種となる中性粒子が枯渇しプラズマ密度が低下する「中性粒子枯渇」が問題となっている。中性粒子枯渇は高周波プラズマ源の密度限界を決める要因の一つとして考えられているだけでなく、プラズマの安定性に悪影響を及ぼすため、応用面においてはこの問題を克服することが課題となっている。本研究では3 流体(中性ガス、電子、イオン)数値計算によってプラズマ圧と中性ガス圧の時空間発展を解明し、中性粒子枯渇を克服するための効果的な中性粒子供給システムを開発する。

    CiNii Research

  • 数値計算による中性粒子枯渇現象の密度限界・密度振動への影響の解明

    2022年 - 2024年

    科学研究費補助金 (文部科学省)

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    担当区分:研究代表者  資金種別:受託研究

  • Qdai-jump Research Program

    2021年

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    担当区分:研究代表者  資金種別:受託研究

▼全件表示

教育活動概要

  • 大学院生卒研性の研究指導。
    大学院での演習。

教育活動に関する受賞

  • 該当なし

       

担当授業科目

  • 課題集約演習

    2020年10月 - 2021年3月   後期

指導学生の受賞

  • 2024年度修士論文地球環境理工学メジャー メジャー賞

    受賞学生氏名:下岡 暉