We derive and examine the general expression for the scattering asymmetry parameter g. For aggregate particles, the asymmetry parameter is made 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 electromagnetic fields between these subsystems. Enhanced backscatter is one phenomenon resulting from these interactions. Numerical results demonstrate that interference effects play a dominant role when the separation distance between two-sphere aggregates is smaller than half the incident wavelength. As the separation distance becomes large, both interference and interaction effects drop off and the asymmetry parameter approaches that of the individual particle constituents.
© 1998 Optical Society of America
Gorden Videen, Ronald G. Pinnick, Dat Ngo, Qiang Fu, and Petr Chýlek, "Asymmetry Parameter and Aggregate Particles," Appl. Opt. 37, 1104-1109 (1998)