针对自然界的非球形粒子问题,对典型非球形粒子的偏振传输特性进行研究,采用T矩阵算法研究椭球、圆柱和切比雪夫粒子的偏振传输特性,及其与球形粒子偏振传输特性的差异。研究结果表明:对于横纵轴之比中等的椭球粒子,当散射角小于60°时,不同形状椭球粒子的偏振度(DOP)差异较小,可用Mie散射方法进行粒子偏振特性的近似计算;当散射角大于60°时,DOP随横纵轴之比的变化较大,且球形与椭球粒子的DOP差异随着横纵轴之比的增加而增大;对于直径与高度之比中等的圆柱体粒子,DOP的变化相比于椭球粒子更加平稳,但后向散射与侧向散射区域仍不能采用Mie散射进行近似计算;形状比例极端的椭球粒子和圆柱体粒子的偏振曲线均类似于钟形,且在散射角约为90°时DOP达到最大值;切比雪夫粒子的形变参数和级次都对粒子前向散射偏振特性的影响较小,但对后向散射偏振特性的影响较大,且灵敏度随级次的增加而减小。本研究结果可为非球形粒子偏振传输特性的研究及球形粒子近似提供理论指导。

We investigate the polarization transmission characteristic of typical non-spherical particles to solve the problems encountered by these particles in nature. The polarization transmission characteristics of the ellipsoid, cylindrical, and Chebyshev particles while applying the T-matrix algorithm and the difference in the polarization transmission characteristics of the spherical particles are studied. The results denote that for the ellipsoid particles with medium ratio of transverse and longitudinal axis, the degree of polarization (DOP) variation with different shapes is very small and can approximate with that for the Mie scattering method when the scattering angle is less than 60°. In case of the scattering angle being larger than 60°, the DOP is rather changeable with different transverse and longitudinal axis ratios. Further, the difference between the spherical and ellipsoid particles significantly changes with the increasing ratio. The DOP variation in case of the cylinder particles with medium ratio of diameter and height is more stable than that observed in case of the ellipsoid particles but is still not suitable for performing Mie scattering approximation in the side-scattering and back-scattering area. The polarization curves for the extreme-ratio ellipsoid and cylinder particles exhibit a shape similar to that of a bell and has the largest DOP at a scattering angle of 90°. The deformation parameters and the levels of Chebyshev particles have little effect on the polarization characteristic in the forward scattering area but considerable influence in the back-scattering area. The sensitivity also decreases with the increasing level. These results provide theoretical guidance for studying the polarization transmission characteristic of the non-spherical particles and the approximation problem of the spherical particles.