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2022 Fiscal Year Annual Research Report

Relativistic reconnection experiment using large-scale laser systems

Research Project

Project/Area Number 20K20285
Research InstitutionOsaka University

Principal Investigator

坂和 洋一  大阪大学, レーザー科学研究所, 准教授 (70242881)

Co-Investigator(Kenkyū-buntansha) 福田 祐仁  国立研究開発法人量子科学技術研究開発機構, 関西光科学研究所 光量子科学研究部, 上席研究員 (30311327)
森田 太智  九州大学, 総合理工学研究院, 助教 (30726401)
Morace Alessio  大阪大学, レーザー科学研究所, 助教 (70724326)
星野 真弘  東京大学, 大学院理学系研究科(理学部), 教授 (90241257)
Project Period (FY) 2020-04-01 – 2023-03-31
Keywords相対論的磁気リコネクション / レーザー宇宙物理学 / 粒子加速 / 協同トムソン散乱計測 / 高出力レーザー / X線自由電子レーザー / X線小角散乱 / プロトンバックライト計測
Outline of Annual Research Achievements

磁気リコネクションでは、プラズマアウトフローの流速が磁場強度に比例するアルフベン速度vA程度となるため、強磁場プラズマ中ではvA がほぼ光速となり、相対論的なリコネクションによる粒子加速がおこる。この相対論的磁気リコネクションの基礎実験として、2つのキャパシタコイルターゲット (CCT) に高出力激光XII号レーザーを照射する事によって得られる100T 級の反平行強磁場を用いた磁気リコネクション実験を行なった。加速された電子のエネルギースペクトルを計測し、対照実験として行なった100T 級の平行強磁場配位での結果と比較を行った。またCCTに流れるコイル電流と磁気リコネクションによって生成されるリコネクション電流の時間発展計測を目的として、高強度レーザーのLFEXを用いたプロトンバックライト計測を行った。さらに、プラズマの温度・密度・流速をプローブレーザーを用いた協同トムソン散乱計測によって求めた。
相対論的臨界密度程度のプラズマに高強度レーザーを入射するとワイベル不安定性によって数 10 kT の自己生成乱流磁気島が発生し、これによる荷電粒子の相対論的磁気リコネクション加速がシミュレーションによって示されている。この不安定性によって生成されるワイベルフィラメント構造の時間・空間発展をX線自由電子レーザー (XFEL)を用いたX線小角散乱 (SAXS) によって計測するための予備実験として、直径と間隔がそれぞれ0.5と1.0 umのロッド集合体ターゲットに高強度レーザーを照射してワイベルフィラメントを模擬した3次元構造のプラズマを生成した。遅延時間の後にXFELを照射してSAXSによってプラズマ膨張にともなう散乱光のフーリエスペクトルの時間発展を計測して膨張速度を求め、バルクプラズマの電子温度Teを導出した。粒子シミュレーションによってこの膨張の物理課程を明らかにした。

  • Research Products

    (24 results)

All 2023 2022 Other

All Int'l Joint Research (2 results) Journal Article (7 results) (of which Int'l Joint Research: 6 results,  Peer Reviewed: 7 results) Presentation (15 results) (of which Int'l Joint Research: 12 results,  Invited: 1 results)

  • [Int'l Joint Research] Helmholtz-Zentrum Dresden- Rossendorf/European XFEL(ドイツ)

    • Country Name
      GERMANY
    • Counterpart Institution
      Helmholtz-Zentrum Dresden- Rossendorf/European XFEL
  • [Int'l Joint Research] University of York(英国)

    • Country Name
      UNITED KINGDOM
    • Counterpart Institution
      University of York
  • [Journal Article] Ultrafast time-resolved 2D imaging of laser-driven fast electron transport in solid density matter using an x-ray free electron laser2023

    • Author(s)
      H. Sawada, et al, Y. Sakawa, et al
    • Journal Title

      Review of Scientific Instruments

      Volume: 94 Pages: 033511-1-7

    • DOI

      10.1063/5.0130953

    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Super-strong magnetic field-dominated ion beam dynamics in focusing plasma devices2022

    • Author(s)
      A. Marace, et al, Y. Sakawa, et al
    • Journal Title

      Scientific Reports

      Volume: 12 Pages: 6876-1-12

    • DOI

      10.1038/s41598-022-10829-1

    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Direct observations of pure electron outflow in magnetic reconnection2022

    • Author(s)
      K Sakai, et al, Y. Sakawa, et al
    • Journal Title

      Scientific Reports

      Volume: 12 Pages: 10921-1-9

    • DOI

      10.1038/s41598-022-14582-3

    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Hydrodynamic instabilities in a highly radiative environment2022

    • Author(s)
      G. Rigon, et al, Y. Sakawa, et al
    • Journal Title

      Physics of Plasmas

      Volume: 29 Pages: 072106-1-10

    • DOI

      10.1063/5.0089994

    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] High-power laser experiment on developing supercritical shock propagating in homogeneously magnetized plasma of ambient gas origin2022

    • Author(s)
      S. Matsukiyo, et al, Y. Sakawa
    • Journal Title

      Physical Review E

      Volume: 106 Pages: 025205-1-7

    • DOI

      10.1103/PhysRevE.106.025205

    • Peer Reviewed
  • [Journal Article] Ultrafast visualization of an electric field under the Lorentz transformation2022

    • Author(s)
      M. Ota, et al, Y. Sakawa, et al
    • Journal Title

      Nature Physics

      Volume: 18 Pages: 1436-1440

    • DOI

      10.1038/s41567-022-01767-w

    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Detection of current-sheet and bipolar ion flows in a self-generated antiparallel magnetic field of laser-produced plasmas for magnetic reconnection research2022

    • Author(s)
      T. Morita, et al, Y. Sakawa
    • Journal Title

      Physical Review E

      Volume: 106 Pages: 055207-1-12

    • DOI

      10.1103/PhysRevE.106.055207

    • Peer Reviewed / Int'l Joint Research
  • [Presentation] 臨界密度近傍の多成分プラズマ中のレーザー駆動無衝突静電衝撃波2023

    • Author(s)
      坂和洋一,他
    • Organizer
      日本物理学会2023年春季大会
  • [Presentation] Toward a new analytical model for collisionless electrostatic shocks2023

    • Author(s)
      Minh Nhat LyTa, kayoshi Sano, Youichi Sakawa, Yasuhiko Sentoku
    • Organizer
      日本物理学会2023年春季大会
  • [Presentation] Small Angle X-ray Scattering and particle measurements of sub-micron rod-assembly target at SACLA2022

    • Author(s)
      Y. Sakawa, et al
    • Organizer
      INTERNATIONAL CONFERENCE ON HIGH ENERGY DENSITY SCIENCES 2022 (HEDS2022)
    • Int'l Joint Research
  • [Presentation] Ultrafast XFEL measurements of relativistic electron isochoric heating in a solid copper foil2022

    • Author(s)
      H. Sawada, et al, Y. Sakawa, et al
    • Organizer
      INTERNATIONAL CONFERENCE ON HIGH ENERGY DENSITY SCIENCES 2022 (HEDS2022)
    • Int'l Joint Research
  • [Presentation] Generation of HED plasma regulated by magnetic field from structured medium -Simulation and experimental study-2022

    • Author(s)
      R. Matsui, et al, Y. Sakawa, et al
    • Organizer
      INTERNATIONAL CONFERENCE ON HIGH ENERGY DENSITY SCIENCES 2022 (HEDS2022)
    • Int'l Joint Research
  • [Presentation] Spectroscopic observation of a strong magnetic field induced in high-density relativistic plasma2022

    • Author(s)
      T. Pikuz, et al, Y. Sakawa, et al
    • Organizer
      INTERNATIONAL CONFERENCE ON HIGH ENERGY DENSITY SCIENCES 2022 (HEDS2022)
    • Int'l Joint Research
  • [Presentation] Laser-driven collisionless electrostatic shock generation in a multicomponent-ion plasma2022

    • Author(s)
      Y. Sakawa, et al
    • Organizer
      13th International Conference on High Energy Density Laboratory Astrophysics (HEDLA2022)
    • Int'l Joint Research
  • [Presentation] Local measurements of laser-driven electron-scale magnetic reconnection2022

    • Author(s)
      K. Sakai, et al, Y. Sakawa, et al
    • Organizer
      13th International Conference on High Energy Density Laboratory Astrophysics (HEDLA2022)
    • Int'l Joint Research
  • [Presentation] Laser ion acceleration with a large-area suspended graphene target from sub-relativistic to relativistic intensities2022

    • Author(s)
      T. Minami, et al, Y. Sakawa, et al
    • Organizer
      13th International Conference on High Energy Density Laboratory Astrophysics (HEDLA2022)
    • Int'l Joint Research
  • [Presentation] Multidimensional ion radiography with AI individually recognizing multicomponent n- particles on solid state nuclear track detectors2022

    • Author(s)
      S. Egashira, et al, Y. Sakawa, et al
    • Organizer
      13th International Conference on High Energy Density Laboratory Astrophysics (HEDLA2022)
    • Int'l Joint Research
  • [Presentation] Single-Shot Measurement of Relativistic Electron Bunch Using Electro-Optic Sampling2022

    • Author(s)
      K. Kan, et al, Y. Sakawa, et al
    • Organizer
      47th International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz)
    • Int'l Joint Research
  • [Presentation] Experimental Study of Electron Impact Ionization between a Relativistic Electron Bunch and a ZnTe Crystal2022

    • Author(s)
      M. Ota, et al, Y. Sakawa, et al
    • Organizer
      47th International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz)
    • Int'l Joint Research
  • [Presentation] Femtosecond dynamics of relativistic electron heating in a high-intensity laser-produced solid-density plasma2022

    • Author(s)
      H. Sawada, et al, Y. Sakawa, et al
    • Organizer
      64th Annual Meeting of the APS Division of Plasma Physics
    • Int'l Joint Research
  • [Presentation] Generation of collisionless shocks using high-energy lasers2022

    • Author(s)
      Y. Sakawa
    • Organizer
      Japan-US High Energy Density Science Center Seminar
    • Int'l Joint Research / Invited
  • [Presentation] High-intensity laser driven ion acceleration by collisionless electrostatic shock in a multicomponent-ion plasma2022

    • Author(s)
      Y. Sakawa, et al
    • Organizer
      地球電磁気・地球惑星圏学会 第152回講演会 (2022年)

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Published: 2023-12-25  

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