On the fluxes induced by interacting fields in multiple scattering

Multiple scattering problems involving point-source excitation of lossy media are considered. The sound fluxes induced by the interactions between the scattered fields are analyzed. Theorems connecting interaction intensities (active and reactive) with the Lagrangian densities and the scattering cross sections are established. Physical bounds regarding cross sections ratios are derived, highlighting the contribution of the interaction-induced intensities to the overall intensity. Explicit results for lossless clusters are given. The case of a cluster composed by point-like scatterers is also analyzed.