Session BC - Bubbles.
ORAL session, Sunday morning, November 24
Room 1, OnCenter
A gas bubble trapped in water by an oscillating acoustic field can emit visible bursts of light. Currently the energy focusing of this phenomenon (sonoluminescence) is understood as the nonlinear convergence of shocks towards the interior of the bubble. We present a complementary but alternative possibility which stems from a linear hydrodynamic instability of the entire gas inside the bubble, leading to the storage of acoustic energy over many bubble oscillations. This mechanism suggests a qualitatively different method for estimating light intensities from the bubble than those given previously, as well as identifying the hydrodynamic parameters coupling to the light intensity. A natural consequence of this mechanism is the locking of the ambient radius, the time between bubble collapses and the light intensity to the phase of the acoustic waves in the bubble.