Author Affiliations
Abstract
1 State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai201800, China
2 Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing100049, China
3 CAS Center for Excellence in Ultra-intense Laser Science, Shanghai201800, China
4 Department of Physics, Shanghai Normal University, Shanghai200234, China
5 ShanghaiTech University, Shanghai201210, China
We report on experimental observation of non-laminar proton acceleration modulated by a strong magnetic field in laser irradiating micrometer aluminum targets. The results illustrate the coexistence of ring-like and filamentation structures. We implement the knife edge method into the radiochromic film detector to map the accelerated beams, measuring a source size of 30–110 μm for protons of more than 5 MeV. The diagnosis reveals that the ring-like profile originates from low-energy protons far off the axis whereas 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.
knife-edge technique laser–plasma interaction non-laminar proton source target normal sheath acceleration Weibel instability High Power Laser Science and Engineering
2022, 10(1): 010000e2
中山大学 光电材料与技术国家重点实验室, 广州 510275
研究了测量光场分布的多角度单刀边法和直角双刀边法。分析了两种刀边法测量光斑特性的基本原理。通过数值模拟，对它们在光斑测量过程中的图像还原能力和抗噪声能力进行了理论分析，并对实验中利用直角双刀边法测量得到的结果进行了简要的分析。研究结果表明，多角度单刀边法在测量光斑的实验中，对光斑的还原能力比较有限，而直角双刀边法由于操作简单、还原能力更强，更适合用于光斑的测量。
刀边法 噪声 光斑 knife-edge technique noise spot 强激光与粒子束
2014, 26(1): 011014
