水雾包裹沙尘颗粒核壳结构的散射特性研究

基于离散偶极子近似法(DDA)，对水雾包裹沙尘颗粒的核壳结构光学特性进行研究，计算了长短轴比例为2∶1的椭球形粒子的核壳结构内、外层厚度及散射角度变化对光散射特性的影响。结果表明，内核大小不变，外层厚度由1.2 μm增大到4.8 μm，核壳双层颗粒散射系数和消光系数由3.4和3.43降低到2.543和2.545，且散射相对强度也明显增大。外层厚度不变，内核厚度由0.6 μm增加到2.4 μm，散射系数和消光系数由3.105和3.111变化为2.76和2.9;可见外层厚度对核壳双层颗粒散射特性的影响更大，这是由于散射光主要与外层物质相互作用引起的。散射相对强度随波长的增加而降低，随核壳结构尺度的增加呈现递增的规律。该结果对大气中气溶胶和水雾共同作用时的散射特性，激光在其中的传输特性等研究有参考价值。

Scattering Properties of Core-Shell Structure of Mist Wrapped Dust Particles

The authors have investigated the optical properties of core-shell structure of mist wrapped dust particles based on the method of discrete dipole approximation (DDA). The influence on the thickness of the elliptical core-shell structure were calculated which the ratio of long axis and short axis is 2∶1, and the change of scattering angle for scattering characteristics. The results shows that the thickness of outer layer increase from 1.2 to 4.8 μm with the scattering and extinction coefficient of double core-shell layers particles decrease from 3.4 and 3.43 to 2.543 and 2.545, when the size of inner core isn’t change. And scattering relative strength also increased obviously. The thickness of inner core increase from 0.6 to 2.4 μm with the of scattering and extinction coefficient change from 2.59 and 2.88 to 2.6 and 2.76 when thickness of outer remain constant. Effect of the thickness of visible outer layer on the scattering characteristics of double core-shell layers particles is greater, because of the interaction between scattering light and outer materials. The scattering relative intensity decrease with wavelength increased, while increased with the scale of core-shell structure increase. The results make a promotion on the study of the transportation characteristics of laser and scattering characteristics when the atmospheric aerosol and water mist interact together.