Interactions of cavitation bubbles observed by high-speed imaging in shock wave lithotripsy

A multi-frame high-speed photography was used to investigate the dynamics of cavitation bubbles induced by a passage of a lithotripter shock wave in a water tank. Solitary bubbles in the free field each radiated a shock wave upon collapse, and typically emitted a micro-jet on the rebound following initial collapse. For bubbles in clouds, emitted jets were directed toward neighboring bubbles and could break the spherical symmetry of the neighboring bubbles before they in turn collapsed. Bubbles at the periphery of a cluster underwent collapse before the bubbles at the center. Observations with high-speed imaging confirm previous predictions that bubbles in a cavitation cloud do not cycle independently of one another but instead interact as a dynamic bubble cluster. © 2006 American Institute of Physics