Interaction of counterpropagating acoustic waves in media with nonlinear dissipation and in hysteretic media

The interaction of sound waves travelling in the opposite directions in med ia with quadratic nonlinearity in analyzed theoretically. It is well-known that quadratic elastic nonlinearity does not provide an effective interacti on of counterpropagating acoustic waves. One of the research results presen ted here is rather expected. It consists of the prediction that in media wi th quadratic nonlinear dissipation a wave travelling in one direction induc es additional attenuation of a wave travelling in the opposite direction. A more interesting result is the prediction that in media with hysteretic qu adratic nonlinearity a strong sound wave travelling in one direction induce s amplification of a weak sound wave travelling in the opposite direction. The threshold of the stimulated backscattering of acoustic waves in the hys teretic media is evaluated. Possible applications include thermoacoustics a nd acoustic diagnostics of micro-inhomogeneous materials. (C) 1999 Elsevier Science B.V. All rights reserved.