New suggestion concerning the origin of sonoluminescence

We suggest a new mechanism where sonoluminescence is produced by the tremendously large adiabatic pressure pulse (shock wave) generated by the close to supersonic (or above) impact of the fluid on the hard core bubble. The light flash is mostly emitted by the fluid surrounding the bubble. enerally, the emission spectrum of any material submitted to a large adiabatic compression is (roughly) globally dilated by some Grüneisen coefficient γ ̄ . Temperature simultaneously increases by the same factor, which increases the power of the emitted radiation by a factor γ ̄ 4 . A rigorous lower bound for the sound velocity in the compressed region at impact is obtained with purely kinematic arguments only assuming the existence of a non-negative Van der Waals volume for the fluid. For supersonic impacts, the increase of the sound velocity reaches at least one order of magnitude (and, with reasonable assumptions, much more), which yields an estimation of the Grüneisen coefficient γ ̄ and indicates it may become very large. Then, during the pressure pulse, the thermal infrared (IR) radiation of the compressed fluid can be extended up to visible–ultraviolet (UV) simultaneously with an intense brightness. namics of collapsing bubbles have been analyzed taking into account fluid compressibility. Shock waves are generated when the bubble, at a minimum radius, suddenly becomes almost incompressible. For impacts close to supersonic (or above), an intense pressure is briefly generated in a sphere which extends beyond the central bubble and which thus mostly contains surrounding fluid compacted to near its Van der Waals volume. This compacted fluid generates an intense emission of UV–visible light which suddenly disappears when the fluid expands from its Van der Waal volume. This situation occurs when the sphere of compacted fluid reaches a critical size of a few minimum bubble radii. Next, this pressure pulse radially propagates through the fluid, initially at highly supersonic velocities, which decay to the normal sound velocity as it simultaneously spreads out.