氏名：Shinsuke FUJIOKA¹, Ryunosuke TAKIZAWA², Tamaki MAEGAWA³, Takumi TSUIDO⁴, King Fai Farley LAW⁵

所属：Institute of Laser Engineering, Osaka University¹, Dept. Phys., Graduate School of Science, Osaka University²-⁵

概要：(Objective) Interaction between high-intensity laser light and matter produces high-energy or fast
electrons. In laser-driven inertial confinement fusion, the energy distribution of the fast electrons
is one of the critical parameters that determine the heating efficiency of fusion fuel. However, it
is hard to measure directly because an electric field around a plasma confines a significant portion
of the fast electron in the plasma. In this study, we develop a method to estimate the energy
distribution of the fast electrons from the spectrum of X-rays emitted by them traveling in a
plasma.
(Description) The process of bremsstrahlung X-ray emission by fast electrons with multiple quasimonoenergetic
energies in the matter is calculated using the Monte Carlo simulation code PHITS
for radiation generation and transport installed in OCTOPUS. The energy distribution of fast
electrons was obtained by reconstructing the experimentally observed X-ray spectrum with the
linear sum of the above Bremsstrahlung X-ray spectra.
(Results) The energy distribution of electrons was successfully estimated from the X-ray spectrum
obtained in the experiment. From the energy distribution, it was directly observed that the fast
electrons were trapped by the electromagnetic field formed around the target.

 

論文掲載,発表実績:
（学術雑誌掲載論文）

• H. Morita and S. Fujioka, “Generation, measurement, and modeling of strong magnetic
  fields generated by laser-driven micro coils,” Rev. Mod. Plasma Phys., vol. 7, no. 1, p. 13,
  (2023).
• R. Takizawa, H. Morita, K. Matsuo, K. F. F. Law, C. Liu, Y. Arikawa, and S. Fujioka, "
  Experimental Investigation of Voltage Generation Mechanism of Laser-Driven Coil", J.
  Phys. Soc. Japan 91, 064501 (2022).
• T. Johzaki, K. Yoshitake, T. Endo, W. Kim, S. Fujioka, H. Nagatomo, H. Morita, R.
  Takizawa, and M. Takemura, "Dependence of resistivity gradient guiding of laser-driven
  relativistic electron beams on laser intensity and duration", Phys. Plasmas 29, 112707
  (2022).
• T. Tamagawa, Y. Hironaka, K. Kawasaki, D. Tanaka, T. Idesaka, N. Ozaki, R. Kodama,
  R. Takizawa, S. Fujioka, A. Yogo, D. Batani, P. Nicolai, G. Cristoforetti, P. Koester, L. A.
  Gizzi, and K. Shigemori, "Development of an experimental platform for the investigation
  of laser-plasma interaction in conditions relevant to shock ignition regime", Rev. Sci.
  Instrum. 93, (2022).

 

（国内研究会等発表論文）

• 日本物理学会2022 年秋季大会12pW621-3 無衝突衝撃波フット領域における不安定性のシミュレーション研究, King Fai Farley Law, 藤岡慎介, 大平豊
• 日本物理学会2022 年秋季大会 15aW621-9 捕捉電子のエネルギー分布計測によるレーザー照射ターゲット表面での電場強度の推定, 前川珠貴, 澤田寛A, 森田大樹, 瀧澤龍之介, Jinyuan Dun, Yubo Wang, 城﨑知至B, 岩田夏弥, 千德靖彦, 有川安信, 藤岡慎介
• 日本物理学会2022 年秋季大会 15aW621-3 波形整形ビームを用いた中実球圧縮における流体不安定性の影響, 瀧澤龍之介, 長友英夫, 有川安信, 森田大樹, 敦近原, 前川珠, 片桐健登, 尾崎典雅, 弘中陽一郎, 重森啓介, 藤域淳平, 安部勇輝, 羽原英明, 蔵満康浩, 城崎知至, 坂上仁志, 中井光男, 白神宏之, 兒玉了祐, 千徳靖彦, 藤岡慎介
• 日本物理学会2022 年次大会23aB1-11 高強度レーザー駆動キロテスラ磁気リコネクションによる粒子加速, King Fai Farley Law, Jinyuan Dun, 安部勇輝, Alessio Morace, 有川安信, 尾崎哲, Phillipp Korneev, Joao Jorge Santos, 藤岡慎介
• 日本物理学会2022 年次大会25aB1-7 硬X 線分光計測への機械学習の適用と妥当性の評価, 前川珠貴, 澤田寛, 城崎知至, 千徳靖彦, 瀧澤龍之介, DUN Jinyuan,築道拓実, LAW Farley King Fai, 藤岡慎介
• 日本物理学会2022 年次大会25pB1-4 高強度レーザーによるプラズマ加熱のレーザーパルス幅依存性, 築道拓実, 瀧澤龍之介, 森田大樹, 前川珠貴, LAW King Fai Farley, 敦近原, MORACE Alessio, 有川安信,千徳靖彦, 城﨑知至, 藤岡慎介