Acoustic cavitation and sonoluminescence

Abstract

The violent collapse of a bubble in an acoustic field can lead to the emission of light, a phenomenon called sonoluminescence (SL). The study of sonoluminescence has led to refinements in understanding cavitation. This talk will focus on three areas of research in which the application of sonoluminescence is used to investigate cavitation: (1) In the field of single-bubble SL, techniques have been improved to study the dynamical motion of the bubble and, with comparisons to SL, models of the bubble dynamics have been refined. In particular, thermal conduction and the trapping of water vapor during the bubble collapse contribute significantly to the internal temperatures and to the dynamics of the cavitation bubble. (2) In lithotripsy, intense shock waves generate cavitation fields which play a role in kidney stone communition. In vitro studies have shown that SL can be correlated with a bubble’s expansion and collapse within the field. (3) In sonochemistry, high-intensity ultrasound is used to initiate or enhance chemical reactions. SL is often observed under these conditions, and in some cases, there is a correspondence between SL intensity and sonochemical yield. Although often overlooked, it can be important to account for the physics and chemistry at the bubble surface.