Interaction types and their like-polarization phase-angle difference signatures

The JPL Airborne Synthetic Aperture Radar (AIRSAR) measures the full polarimetric properties of scene objects. AIRSAR data contain a complete set of magnitudes (for all linearly-polarized combinations (viz., VV, HH, and CS (cross Polarization))) and phase-angle differences (for all pairs of linearly-polarized components) for each image pixel. Radar images users have been greatly interested in the like-polarization (LK) phase-angle difference parameter, delta phi(sub LK). Usually, it is associated with the type of interaction between microwaves and scene-object scattering-elements. One value of delta phi(sub LK) is said to be produced by a dominant single scattering (or reflection) event, and another value is said to be the result of a dominant double-scattering (or double reflection) event. these are often called 'single bounce' and 'double bounce' interaction signatures, respectively. There appears to be a significant amount of confusion about how the interaction processes produce the characteristic values of delta phi(sub LK) and about what value of delta phi(sub LK) should be associated with each specific type. This issue is addressed.