Approximate formula for second-order rayleigh scattering from N acoustical scatterers

A model of second-order multiple scattering from N Rayleigh acoustical scatterers distribted at random throughout a volume V is analyzed, physically motivated approximations being used. The result is a simple expression for the angular distribution of the total second-order Rayleigh scattered flux that is analogous to the usual formula for first-order scattering from N independent scatterers.