プラズマ不安定性の詳細な観測に成功 (Physicists Capture Elusive Plasma Instability in Unprecedented Detail)

2025-03-07 インペリアル・カレッジ・ロンドン (ICL)

＜関連情報＞

• https://www.imperial.ac.uk/news/261677/physicists-capture-elusive-plasma-instability-unprecedented/
• https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.134.025102

超臨界密度プラズマにおけるレーザー駆動高速電子ワイベル状フィラメント形成の光学イメージング Optical Imaging of Laser-Driven Fast Electron Weibel-like Filamentation in Overcritical Density Plasma

N. P. Dover, O. Tresca, N. Cook, O. C. Ettlinger, R. J. Kingham, C. Maharjan, M. N. Polyanskiy, P. Shkolnikov, I. Pogorelsky et al.
Physical Review Letters  Published: 17 January, 2025
DOI:https://doi.org/10.1103/PhysRevLett.134.025102

Abstract

We report on the measurement of filamented transport of laser-generated fast electron beams in near-critical density plasma. A relativistic intensity long-wave-infrared laser irradiated a hydrodynamically shaped helium gas flow at an electron density ≃10²⁵  m⁻³, generating a large flux of fast electrons that propagated beyond the critical surface. The beam-to-background electron density ratio was sufficiently high to drive growth of Weibel-like filamentation, which was measured by optical probing to extend up to 800  μ⁢m with radii ∼10  μ⁢m. Particle-in-cell simulations reproduce the main features of the filamentation generation, suggesting that collisionless processes are dominant in these interactions. Expansion of the filaments after formation infers a fast electron heated plasma temperature ∼400  eV in the overcritical density plasma.