1.06μm激光气溶胶凝聚粒子散射特性

Scattering characteristics of aerosol aggregation particles of 1.06μm laser

气溶胶是大气电磁环境中的重要组成部分,气溶胶粒子严重影响1.06μm激光的传输特性。单次散射反照率和不对称因子是研究气溶胶中激光传输特性的一个重要参量。基于CCA模型,模拟了由64个球形原始微粒凝聚而成的四种取向气溶胶凝聚粒子。利用离散偶极子近似方法,数值计算了1.06μm激光入射情况下四种形状气溶胶凝聚粒子的单次散射反照率和不对称因子随入射角变化的值;并分析了尺寸参数对单次散射反照率和不对称因子的影响。结果显示:对于相同数目原始微粒的气溶胶凝聚粒子,其单次散射反照率和不对称因子明显依赖于入射光的入射角度和气溶胶凝聚粒子的形状;对于不同尺寸参数的气溶胶凝聚粒子,其单次散射反照率和不对称因子随尺寸参数的增大而增大,当尺寸参数大于3时,气溶胶凝聚粒子的散射主要集中于前向散射。

The aerosol is an important ingredient of atmospheric electromagnetic environment, the aerosol particles affect on the transmission of 1.06μm laser seriously. The single scattering albedo and asymmetry factor is an important parameter for the research on the laser transmission characteristics in aerosol. Cluster-cluster aggregation （CCA） model was used to simulate four kinds of aerosol aggregation particles consisting of 64 spherical original particles. Combined with the discrete dipole approximation method, the value of single scattering albedo and asymmetry parameter under different incident angles with 1.06 μm laser incident were numerically calculated, and the influence of the size parameters of the single scattering albedo and asymmetry factor was analyzed. The results show that the single scattering albedo and asymmetry factor are significantly dependent on the incident angle and shapes for the aerosol aggregation particles with same number of original particles. And for the aerosol aggregation particles with different size parameters, the single scattering albedo and asymmetry factor increases with increasing size parameter, when the size parameter is greater than 3, the scattering of aerosol aggregation particles is mainly concentrated in the forward scattering.