为满足快点火对点火脉冲功率的要求, 主要在建和规划中的快点火驱动器均提出类似天文望远镜的拼接技术, 实现大口径多路激光的相干聚焦。采用几何光学追迹和傅里叶方法求解拼接聚焦模型, 针对抛物面镜的拼接规模和控制精度对焦斑峰值功率的影响进行了理论和数值模拟研究。模拟了2×2, 3×3和4×4拼接离轴抛物面镜在一定控制精度下远场焦斑的斯特列尔比, 并由正态分布的蒙特-卡罗方法分析了精度误差对斯特列尔比的影响。结果表明, 面外旋转角和轴向活塞位移误差分别为1 μrad和210.6 nm时2×2结构的焦斑斯特列尔比大于0.8的概率超过60%。

In order to meet the ignition pulse power requirements for fast ignition, fast ignition drivers being constructed and planned mainly adopt similar technology of segmented primary mirrors as the astronomical telescopes, realizing large-aperture multi-channel laser coherent focusing. Using the geometrical optics tracing and Fourier method to solve the model of tiling focusing, the effect of tiling scale of parabolic mirrors and control precision on focal-spot peak power is studied by theory and numerical simulation. Under certain control precision, the Strehl ratio of far-field focal spot is simulated on 2×2, 3×3 and 4×4 tiling scales of off-axis parabolic mirrors, and the effect of precision error on focal-spot Strehl ratio is statistically analyzed by Monte-Carlo method of normal distribution. The results show that the probability of strehl ratio larger than 0.8 is over 60%, when the errors of outside-plane rotation angles and piston motion are respectively 1 μrad and 210.6 nm the 2×2 structure.