强激光稳态热晕效应的数值模拟研究

为了研究强激光在大气传输过程中产生的热晕效应,采用数值模拟的方法,对无风时稳态热晕效应的影响参数进行了求解,探讨了无风稳态热晕效应对轴上光强以及远场能量分布的影响。结果表明,无风稳态热晕效应存在时,随发射功率的增大,一定传输距离截面上的峰值功率密度先增大后减小;截面上的峰值光强随基模高斯光束的腰斑半径的增大而增大;随着传输距离的增大,截面上峰值光强在逐渐减小,能量在逐渐向周围扩展;在一定条件下,截面上的光强分布会呈现中心光强小于周围光强的“草帽型”分布。该结论对研究强激光在远场的辐照效应是有帮助的。

Numerical simulation of steady-state thermal blooming about high power laser

When high power laser transmits in the atmosphere,thermal blooming will be generated.In order to study the phenomenon,the effect parameters to steady-state thermal blooming without wind are solved in detail by numerical simulation.It is studied that both epaxial light intensity and energy distribution at far field are affected by steady-state thermal blooming without wind.The study results indicate that as emission power increases,the peak power density on the section of a certain distance will increase firstly,then it will descend and that the peak light intensity on the section will increase with the increasing of spot radius of basic mode Gaussian beam.As the propagation distance increases,the peak light intensity on the section will descend gradually,and the laser energy will spread.The light intensity distribution exhibits straw hat shape on a certain conditions,in other word to say,the central light intensity is less than acroteric light intensity.The results is helpful to the research of high power laser's irradiation effect at far field.