A self-starter for the parabolic equation method

An efficient method is developed for generating accurate starting fields for the parabolic equation (PE) method for both fluid and solid media. The self-starter, which is constructed by solving a one-dimensional boundary-value problem (BVP) involving the PE operator, is more efficient than the normal-mode starter, which requires the solution of a large number of similar BVPs. The self-starter depends on the depth-dependent properties of the medium and satisfies all interface and boundary conditions. Since the self-starter is based on higher-order parabolic approximations, it is accurate for problems involving wide propagation angles, large depth variations in the properties of the medium, low frequencies, interface waves, and the continuous spectrum.