漂移对聚焦高斯光束闪烁影响的数值模拟

 采用非自适应坐标变换对聚焦高斯光束在湍流大气中的传输进行了数值模拟，结果显示轴闪烁指数并没有出现如Rytov理论所预言的随初始光束半径的增大而明显减小的现象，其原因在于Rytov近似理论未考虑大尺度湍涡产生的漂移效应对闪烁的贡献。对比数值模拟结果与漂移理论结果以及相关实验结果，三者相吻合,表明未考虑漂移效应的Rytov近似理论不能完全准确地描述聚焦光束的闪烁特征，在研究聚焦光束的闪烁时，应当考虑漂移的影响。

Simulation of effects of beam wander on scintillation index of a focused Gaussian-beam

The propagation of a focused Gaussian beam through turbulent atmosphere is simulated by using non-adaptive coordinate transformation.The first-order weak-fluctuation Rytov theory predicts that the on-axis scintillation index would become significantly smaller as the initial beam width increases.But the simulation results show that there is no great reduction of on-axis scintillation index.This discrepancy is due to the fact that Rytov theory does not correctly account for the effects of beam wander caused by large scale turbulence.Simulation results are in good agreement with beam wander theory results and experimental data.It can be concluded that Rytov theory could not correctly calculate the scintillation index of a focused beam and the effects of beam wander should be taken into account in studying the scintillation of a focused beam.