Characterization of sub-picosecond laser-produced fast electrons by modeling angularly resolved bremsstrahlung measurements with 3D hybrid particle-in-cell code
Characterization of sub-picosecond laser-produced fast electrons by modeling angularly resolved bremsstrahlung measurements with 3D hybrid particle-in-cell code
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DOI：
10.1063/5.0089464
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发表时间：
2022-09
影响因子：
2.2
通讯作者：
L. Chen;H. Sawada
中科院分区：
文献类型：
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作者：
L. Chen;H. Sawada
由强激光产生的快电子与固体相互作用产生的硬x射线是产生高密度物体和惯性约束聚变内爆核的射线照片的重要来源。硬X射线源的精确计算需要三维（3D）模拟几何结构，其完全模拟电子输运动力学，包括电子再循环和绝对光子产率的产生。到目前为止，激光产生的韧致辐射光子在几十皮秒和代码基准的三维模拟还没有明确执行。在这项研究中，我们的特点亚皮秒激光产生的快电子建模角分辨韧致辐射测量的三维混合粒子在细胞（PIC），大规模等离子体代码的非金属靶。用50 TW Leopard激光（15 J，0.35 ps，2 × 1019 W/cm 2）聚焦于100 μ m厚的铜箔和带有大塑料背衬的Cu（Cu-CH靶）上，获得了韧致辐射和逃逸电子数据。复制Cu和Cu-CH靶的数据用于具有给定的一组电子参数的模拟。模拟的比较表明，从Cu靶的硬X射线发射的持续时间显着长于从Cu-CH目标。基准混合PIC代码可以被证明是一个强大的工具，在设计和优化的时间和角度依赖的韧致辐射源闪光X射线和γ射线照相。
Hard x-rays produced by intense laser-produced fast electrons interacting with solids are a vital source for producing radiographs of high-density objects and implosion cores for inertial confinement fusion. Accurate calculation of hard x-ray sources requires a three-dimensional (3D) simulation geometry that fully models the electron transport dynamics, including electron recirculation and the generation of absolute photon yields. To date, 3D simulations of laser-produced bremsstrahlung photons over tens of picoseconds and code benchmarking have not been performed definitively. In this study, we characterize sub-picosecond laser-produced fast electrons by modeling angularly resolved bremsstrahlung measurements for refluxing and non-refluxing targets using the 3D hybrid particle-in-cell (PIC), Large Scale Plasma code. Bremsstrahlung radiation and escaped electron data were obtained by focusing a 50-TW Leopard laser (15 J, 0.35 ps, 2 × 1019 W/cm2) on a 100- μm-thick Cu foil and a Cu with a large plastic backing (Cu–CH target). Data for both the Cu and Cu–CH targets were reproduced for simulations with a given set of electron parameters. Comparison of the simulations revealed that the hard x-ray emission from the Cu target was significantly longer in duration than that from the Cu–CH target. The benchmarked hybrid PIC code could prove to be a powerful tool in the design and optimization of time- and angular-dependent bremsstrahlung sources for flash x-ray and gamma-ray radiography.