Theoretical analysis of the influence of weakly divergent beams on the formation of the spatio-temporal structure of pulse signals in the Sea of Japan

Using numerical modeling based on the mode theory and the geometric-acoustic approximation, it was determined that along with the classical quadruples of pulses present in the space-time field structure, the emergence of additional signals with relatively short delays is caused by the formation of weakly divergent multimode beams in the underwater sound channel of the Sea of Japan, which correspond to smooth extrema in the dependences of the spatial interference period of neighboring modes and their group velocity on the mode number. For one of the two sound speed profiles typical for the Sea of Japan, it was shown that at relatively high frequencies it is possible to receive two groups of additional signals, which correspond to weakly divergent beams formed by modes of relatively low and high orders.

oceanic waveguides, underwater channels, weakly divergent beams, pulsed signals, space-time structure