Energy Focusing in a Converging Fluid Flow: Implications for Sonoluminescence

Cavitation induced by a converging flow leads to such a powerful concentration of energy that subnanosecond flashes of light with an ultraviolet spectrum are emitted. Light intensity is enhanced a factor of 5000 by using xenon rather than helium. This xenon enhancement is similar to that seen with surface bubbles and acoustically driven bubbles in nonaqueous fluids, but contrasts with acoustically driven bubbles in water where xenon is only 5 times brighter than helium. This system has been studied with the goals of obtaining sonoluminescence from diatomic gases and learning about those aspects of sonoluminescence which are properties of a single collapse.