This proposal is for, "Experimentally Probing the Unknowns of Sonoluminescence". Sonoluminescence is the emission of visible radiation from cavitation bubbles of gas produced in a liquid by standing sound waves. The bubbles are trapped at nodes of the standing sound waves and at high intensity the pulsations of the bubble with pressure oscillations of the sound wave are large enough to prevent the bubble from dissolving into the surrounding liquid. At higher levels of sound, a threshold is reached at which the bubble motion abruptly switches to a state where pulsations are so enormous and nonlinear that the resulting supersonic inward collapse of the bubble concentrates the acoustic energy by over 13 orders of magnitude, so as to emit picosecond flashes of broad band light which extend well into the ultraviolet and which, furthermore, are synchronous with the sound field to picosecond accuracy. This phenomena is not understood but it has been shown to have large effects in catalyzing some chemical processing, in causing erosion of hardened metal surfaces and possibly in forming new materials.
