Session 1pBB: Biomedical Ultrasound/Bioresponse to Vibration 1pBB9. Cooperative radiation and losses in bubble clusters

In existing models for single bubble dynamics it is necessary to account for radiation damping, a consequence of fluid compressibility. A similar correction is necessary when modeling systems of coupled bubbles. The coupling alters the collective dynamics and therefore the acoustic power radiated. In the linear approximation and for compact clusters in which the bubbles pulsate in phase, the radiation damping per bubble increases in proportion to the number N of bubbles in the cluster, and the acoustic power is N times greater than is radiated by the cluster in the absence of bubble interaction. The latter effect is relevant to passive detection of cavitation noise as an indicator of the onset and degree of cavitation in therapeutic applications such as shock wave lithotripsy and high‐intensity focused ultrasound. The effect that collective radiation damping has on the dynamics of several simple systems is considered for both small and large pulsations. [Work supported by the ARL:UT McKinney Fellowship in Acoustics and NIH DK070618.]