ASYMMETRY PARAMETER AND AGGREGATE PARTICLES

We derive and examine the general expression for the scattering asymme try parameter g. For aggregate particles, the asymmetry parameter is m ade up of two terms. One term accounts for interference effects of the electromagnetic fields radiating from the individual subsystems. The other term contains the effects of the interaction of the electromagne tic fields between these subsystems. Enhanced backscatter is one pheno menon resulting from these interactions. Numerical results demonstrate that interference effects play a dominant role when the separation di stance between two-sphere aggregates is smaller than half the incident wavelength. As the separation distance becomes large, both interferen ce and interaction effects drop off and the asymmetry parameter approa ches that of the individual particle constituents. (C) 1998 Optical So ciety of America.