含气泡粒子辐射特征的有效介质理论适用性研究

采用离散偶极近似法和Bruggeman有效介质理论分别计算了气泡个数为49、99、149、199、249和299的含气泡粒子的辐射特性参数.比较分析后发现:对于衰减因子、吸收因子和散射因子,在气泡数目小于一定值时,有效介质理论具有较好的适用性,反之适用性较差;对于单次散射反照率和非对称因子,有效介质理论均具有较好的适用性.同时证明了Michael教授关于有效介质理论对含气泡粒子适用性推测的片面性.

Validity of effective medium theory in radiative properties of porous particles

Abstract: The model of porous particles was built in this paper, and the optical properties of them were carried out utilizing discrete dipole approximation and Bruggeman effective medium theory for the number of air pockets from 49 to 299. After analyzing and comparing the scattering properties of porous particles obtained by two computing methods, we found that the effective medium theory has a good validity for the extinction efficiency, the absorption efficiency and the scattering efficiency when the number of air pockets less than a certain value, but not vice versa. While for the single-scattering albedo and the asymmetric factor, the effective medium theory always keeps a good validity in the research scope of this paper. The results also revealed that the inference of the doctor Michael about the validity of effective medium theory in light scattering of porous particles was not comprehensive.