ACOUSTIC BACKSCATTERING FROM MANGANESE NODULES - FEATURES CAUSED BY THE SHORT-RANGE ORDER OF NODULE ARRANGEMENT

This paper analyzes arrangements of manganese nodules covering the oce an bottom, which are referred to as short-range order. We note a simil arity of the mutual layout of nodules and a statistically isotropic ar rangement of nonoverlapping spheres on a plane with a size distributio n typical of nodules. We analytically approximate the radial distribut ion function of nodules by an approximation of the radial function of identical spheres averaged over the sphere-size scatter. In the framew ork of this approximation, the frequency-angular profile of backscatte ring from nodules is determined with allowance for the short-range ord er. We reveal and analyze the backscattering features caused by the sh ort range order of nodule arrangement, specifically interference scatt ering, to give their physical interpretation. Experimental angular and frequency profiles of the nodule backscattering strength are compared with theoretical functions calculated with allowance for the short-ra nge order.