Abstract (Invited)

Sonoluminescence and Sonofusion

L.A.Crum, T.Matula (Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA, USA)

e-mail: lac@apl.washington.edu

When an acoustic wave of moderate pressure amplitude is propagated through an aqueous liquid, light emissions can be observed. This conversion of mechanical energy into electromagnetic energy is called Sonoluminescence (SL) and represents an energy amplification per molecule of over eleven orders of magnitude! The discovery that a single, stable gas bubble, acoustically levitated in a liquid, can emit optical emissions each cycle for an unlimited period of time stimulated considerable interest in this topic. Presumably, the oscillations of the bubble cause the gas in the interior to be heated to incandescent temperatures during the compression portion of the cycle. Because the lifetime of the optical pulse can be on the order of 50 picoseconds, it is likely that some rather unusual physics is occurring. One explanation for the short pulse length is that a shock wave is created in the gas which is then elevated to high temperatures by inertial confinement. If shock waves are the mechanism for SL emission, then optimization of the process has been speculated to lead to extraordinary physics, including nuclear fusion. Recent reports (Science, vol. 295, 1868-1873, 2002) have even provided evidence for these nuclear emissions. A broad review of this intriguing phenomenon will be presented as well a critical review of the potential for sonofusion.

Section : 4