Self-demodulation effects in nonlinear focused beams

In this work, spatial distributions of acoustic pressure of the nonlinear focused sound beams are presented. Focused acoustic beams of periodic waves with an initially Gaussian amplitude distribution are considered. The numerical algorithm is based on the numerical solution of the nonlinear parabolic Khokhlov-Zabololotskaya-Kuznetsov (KZK) equation. The presented model enables to study the process of nonlinear generation of a low-frequency signal by the amplitude modulated high-frequency carrier wave.