采用DDA方法分析非球形粒子辐射特性

Analysis of the radiative properties of non-spherical particles by discrete dipole approximation method

利用离散偶极子近似法(DDA)计算了三种几何形状、不同尺度参数、不同复折射率的非球形粒子随机取向时的衰减因子、反照率和散射相函数等辐射特性参数,并与等体积球形粒子进行了比较.分析结果表明:非球形粒子的辐射特性与等效球形粒子的辐射特性存在着差别,这种差别随着粒子的形状、尺度参数和复折射率等参数的变化而变化,并且具有一定的规律,同时存在一个临界尺度参数,此时非球形粒子与等效球形粒子的辐射特性差别可忽略不计.

The radiative properties of three non-spherical particles （cube, ellipsoid and cylinder）, such as the extinction efficiency factor, scattering albedo and phase function, were studied using discrete dipole approximation （DDA） method under the conditions of different size parameters and complex refractive indexes. Comparison of the radiative properties between non-spherical particles and equivalent-volume spheres shows that the discrepancies between them change with the different parameters of shape, size and complex refractive indexes. Furthermore, it should be noted that when a critical size parameter exists, the non-spherical effect on the radiative properties＇can be ignored.