Mapping non-laminar proton acceleration in laser-driven target normal sheath field
在激光驱动的目标法向鞘场中映射非层流质子加速度
レーザー駆動ターゲットの通常のシースフィールドにおける非層流陽子加速のマッピング
레이저 구동 대상 정상 시스 필드에서 비층형 양성자 가속도 매핑
Mapeo de la aceleración de protones no laminar en el campo de la vaina normal objetivo impulsado por láser
Cartographie de l'accélération non laminaire des protons dans le champ de gaine normal d'une cible commandée par laser
Картирование неламинарного ускорения протонов в поле нормальной оболочки лазерной мишени
¹ State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
中国 上海 中国科学院上海光学精密机械研究所 强场激光物理国家重点实验室
² Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
中国 北京 中国科学院大学 材料科学与光电技术学院
³ CAS Center for Excellence in Ultra-intense Laser Science, Shanghai 201800, China
中国 上海 中国科学院 超强激光科学卓越创新中心
⁴ Department of Physics, Shanghai Normal University, Shanghai 200234, China
中国 上海 上海师范大学物理系
⁵ ShanghaiTech University, Shanghai 201210, China
中国 上海 上海科技大学
High Power Laser Science and Engineering, 23 November 2021
Abstract
We report on experimental observation of non-laminar proton acceleration modulated by strong magnetic field in laser irradiating micron-meter Aluminum targets. The results illustrate coexistence of ring-like and filamentation structures. We implement the knife edge method into the radiochromic film detector to map the accelerated beams, measuring source size of 30 ~ 110 μm for proton of > 5MeV. The diagnosis reveals that the ring-like profile originates from low energy protons far off the axis while the filamentation is from the near-axis high energy protons, exhibiting non-laminar features.
Particle-in-cell simulations reproduced the experimental results, showing that the short-term magnetic turbulence via Weibel instability and the long-term quasi-static annular magnetic field by the streaming electric current account for the measured beam profile. Our work provides direct mapping of laser-driven proton sources in the space-energy domain and reveals the non-laminar beam evolution at featured time scales.
