The roles of multiple scattering and wave interference on dependent scattering by parallel fibers

The respective contributions of multiple scattering and wave interference on dependent scattering by a collection of closely spaced parallel fibers were investigated in this paper. The former is primarily a near-field effect and the latter occurs in the far field. The present analysis first employs the formulation for the full dependent scattering theory which accounts for both the near- and the far-field wave interactions. These effects were then successively removed to derive the scattering properties for different approximations. Expressions for the scattering and extinction cross sections, as well as the general form factor for oblique incidence, were obtained when multiple scattering is neglected. The validity of neglecting multiple scattering is evaluated from both physical and analytical considerations. Neglecting multiple scattering is shown to result in incorrect scattering properties, except for small fiber sizes. The error caused by neglecting multiple scattering decreases when the fibers approach the Rayleigh limit and when the inter-fiber separation is large.