 Solutions to this equation have been developed using Green's functions [4,5] and Parabolic Equation (PE) Methods, most notably via the Kokhlov–Zablotskaya–Kuznetzov (KZK) equation.An alternate mathematical formalism using Fourier operator methods in wavenumber space, was also developed by Westervelt, and generalized in [1] for solving the WLE in a most general manner.The solution method is formulated in Fourier (wavenumber) space in a representation related to the beam patterns of the primary fields generated by linear sources in the medium.