THE TIME-MARCHED FFP FOR MODELING ACOUSTIC PULSE PROPAGATION

Fast-field programs (FFP's) have emerged as an important tool for predicting transmission loss in an ocean waveguide. Such models have been primarily used for time-harmonic sources ; however, pulses or other broadband sources may be treated by Fourier synthesis. We develop a new technique which provides a direct solution by marching the solution forward in time. As an example of the method we consider a pulse incident on an interface between two homogeneous half-spaces. Snapshots of the pulse in time illustrate graphically the effects on the reflected and transmitted waves.