The large range of applications of acoustical methods and techniques in modern society demands a thorough exploration of the nonlinear properties of sound wave propagation in different media and environments, and of the effects caused by nonlinear interaction of sound and medium. The great range of interesting physical phenomena which occur in nonlinear acoustics helps stimulate the extensive research in the field.

These are the proceedings of the 18th International Symposium on Nonlinear Acoustics (ISNA).The ISNA series, held once every three years, is the premier symposium devoted to the field of nonlinear acoustics. Nonlinear acoustical phenomena appear when the sound amplitude is sufficiently large. Then the sound wave is deformed and shocks and sound of new frequencies are created. Earthquake and sonic booms are undesired nonlinear acoustical phenomena; nondestructive testing and cancer sound beam therapy are useful nonlinear acoustical applications. This book is unique in bringing into relief the common physical foundation of so different phenomena and applications.

Physically interesting phenomena appear when sound amplitude is increased to be finite. For example, such a sound deforms its waveform during propagation and shock front forms finally. This means that frequency components that do not exist originally are newly created. There are various interdisciplinary research fields branches that treat nonlinear acoustics. Sonic booms and earthquakes are undesired phenomena in nonlinear acoustics; nondestructive testing and biomedical ultrasonic therapy are practically applied in industrial and medical fields; sonochemical reaction due to cavitational collapse can be used for initiation or enhancement of catalytic reaction; thermoacoustic systems have a promising potential for solving global heat problems. This book provides a useful resource and current reference for scientists and engineers who actually work on or are interested in such problems in nonlinear acoustics.

State College, Pennsylvania, 18-22 July 2005