Scattering by Non-Spherical Particles of Size Comparable to a Wavelength: A New Semi-Empirical Theory
We propose an approximate method for evaluating the interaction of randomly oriented, non-spherical particles with the total intensity component of electromagnetic radiation. When the particle size parameter, x, the ratio of particle circumference to wavelength, is less than some upper bound xo (~5), Mie theory is used. For x > xo, the interaction is divided into three components: diffraction, external reflection, and transmission. Physical optics theory is used to obtain the first of these components; geometrical optics theory is applied to the second; and a simple parameterization is employed for the third. The predictions of this theory are found to be in very good agreement with laboratory measurements for a wide variety of particle shapes, sizes, and refractive indexes. Limitations of the theory are also noted.
KeywordsPhase Function Scattering Angle Irregular Particle EMPIRICAl Theory External Reflection
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