Sonoluminescence energy
DOI: 10.1063/1.2408490
Sonoluminescence energy is mainly chemical, according to a new set of experiments at the University of Illinois. Yuri Didenko and Kenneth Suslick quantified the energy consumption during sonoluminescence, the conversion of ultrasonic waves into picosecond light pulses via rapid oscillations of bubbles in a liquid. They found that, during the compression phase, a bubble’s interior gets hot enough to dissociate many gas molecules and initiate a furious session of chemical reactions. The researchers carefully monitored the reactant products—mostly nitrite ions (NO− 2), hydroxyl radicals (OH•), and light—of a single bubble of air in a bath of water subjected to ultrasound. They found that about 100 times more energy goes into chemical reactions than into light. Their experimental conditions were very different from those used for the recent claim of “sonofusion” (see Physics Today, April 2002, page 16 ), and thus their results may not apply to that claim. However, Dan Shapira and Michael Saltmarsh of Oak Ridge National Laboratory did duplicate the sonofusion conditions. They showed that the earlier coincidence data can be accounted for by random coincidences; they also placed an upper limit on the relevant neutron emission that is 104 less than that implied by the earlier claim. (Y. T. Didenko, K. S. Suslick, Nature 418, 394, 2002 http://dx.doi.org/10.1038/nature00895 .
