APPROXIMATIONS TO EXTINCTION FROM RANDOMLY ORIENTED CIRCULAR AND ELLIPTICAL CYLINDERS

摘要

Analytic approximations to the extinction efficiency, Q(ext), are given for oriented and randomly oriented circular infinite cylinders based on anomalous diffraction. The results are compared with the exact code. These results are further generalized to randomly oriented elliptical cylinders. With the use of the formulas, Q(ext) can be evaluated over 10(4) times faster than with the exact code. This approximation is valid for complex refractive indices m = n - ik, where 1 less than or equal to n less than or equal to infinity and 0 less than or equal to k less than or equal to 3, aspect ratios from 1 to 4, and modest to large particle sizes. The accuracy and limitations of these formulas are discussed. Key words: Extinction, scattering, aerosols, cylinders. (C) 1996 Optical Society of America [References: 18]