SCATTERING PHASE FUNCTION FOR FIBROUS MEDIA

The formulation and evaluation of the effective phase function for fibrous media with any fiber orientation are presented based on the assumption that the fibers are infinite cylinders and scattering is in the independent regime. The phase function is derived in terms of the scattering angle which is the angle between the incident and the scattered radiation. Unlike spherical particles which scatter radiation into all directions, radiation scattered by cylindrical fibers only propagates into limited angular ranges. Hence, the maximum value of the scattering angle for radiation scattered by a collection of fibers depends on the orientation of the fibers relative to the direction of the incident radiation. For a given fiber orientation both the angular variation and the maximum scattering angle of the phase function are different for different incident directions. If the fibers are randomly oriented in space, the angular variation of the phase function is independent of the incident direction and the maximum scattering angle is π. The phase function for fibrous media always exhibits a strong peak in the direction of incident radiation, indicating that the scattering is highly anisotropic. © 1990.