With little more than acetone and sound waves in a beaker, researchers from the US Oak Ridge National Laboratory, the Rensselaer Polytechnic Institute in New York and the Russian Academy of Sciences claim to have seen nuclear fusion. Mindful of the cold-fusion episode of 1989, however, the scientific community is reserving judgement until the results have proved reproducible.
This is the latest apparent manifestation of sonoluminescence, whereby light is emitted by bubbles collapsing in a liquid excited by sound. Observations of the light suggest that implosions provoked by high-frequency sound could create extremely high temperatures and pressures - high enough, perhaps, to lead to conditions that could fuse two atomic nuclei.
The researchers used neutrons to induce the formation of bubbles in liquid acetone in which the hydrogen atoms had been replaced by deuterium. Sonoluminescence resulted in the observation of light accompanied by neutrons. Tiny quantities of tritium were also detected. The researchers hypothesized that nuclear fusion had occurred, since the neutrons had different energies from those used to induce bubble formation, and tritium is an expected by-product. When the experiments were repeated with hydrogenous acetone no tritium or neutrons were observed.
Reference
R Taleyarkhan et al. 2002 Science 295 (5561) 1868-1873.