Selective Excitation of Waveguide Modes Using a Horizontal Array of Monopoles

The spatial structure of a far-field acoustic wavefield created by a sparse horizontal array of nondirectional emitters is considered. It is shown that the array can selectively excite certain modes of the acoustic wavefield. The number of an excited mode depends on the angle with respect to the array axis. The results of numerical simulation are presented for two models of a waveguide and for an array mounted at the ocean bottom. It is shown that the efficiency of single mode excitation grows with an increase in the modal number. The angular dependence of the excited modal spectrum is studied. It is shown that this dependence consists of several branches corresponding to the most excited modes.