High-power acoustic beams: self-action of discontinuous waves, focusing of pulses, and extracorporeal lithotripsy

This paper is a review of the studies of high-power acoustic beams, the results of their practical use and prospects for the future. A simplified self-consistent system of equations is presented to describe the behavior of an acoustic beam in liquid, with consideration for the excitation of the entropy and vortex modes and their reverse effect on the acoustic field. Experiments on thermal self-focusing of both quasi-harmonic and discontinuous waves are described, and the self-focusing of sawtooth waves is computed in a geometrical acoustics approximation. The possibility of inertialess self-focusing of sound in a medium with cubic nonlinearity is discussed. The state of the art of extracorporeal lithotripsy - a rapidly developing field at the junction of medicine and nonlinear acoustics is reviewed, and methods for calculating the focusing of high-pow acoustic pulses are described.