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In a sound field a bubble is forced to oscillate and behaves like a strongly nonlinear oscillator. Moreover, this oscillator alters its parameters by diffusion of gas into and out of the bubble and opens up new dimensions when starting surface oscillations. Theoretical models that incorporate these phenomena are investigated. Part of the parameter space given by the amplitude and frequency of the sound field and by the bubble radius is scanned to get the regions of stable bubble oscillations with respect to diffusion and surface oscillations. Experimentally, single bubbles can be investigated best either by keeping them in a trap or by generating them by focused laser light. For interaction studies with two bubbles a trapped bubble and a laser bubble have been taken. The motion of the bubbles and their interaction is studied by high speed photography and compared with bubble interaction models. [ABSTRACT FROM AUTHOR]

The behavior of mutually coupled cavitation bubbles can change considerably when a finite speed of sound propagation in the liquid is taken into account. This holds for the radial oscillations of the bubbles as well as for the interaction (Bjerknes) forces between them. Starting from linear analysis of the equations of motion, nonlinear bubble dynamics is investigated numerically. Some results are reported for illustration of effects that may have significant impact on the modeling of cavitation structures in certain parameter regimes. [ABSTRACT FROM AUTHOR]