Small, Warm Fusion
For all the interest in useful renewable energy technologies such as wind and solar power, nuclear fusion remains the ultimate "alternative energy", even as it remains a distant prospect. Although the "Cold Fusion" fiasco of 1989 gave the pursuit of small scale fusion a bad name, interesting work is going on in another bench-scale possibility, involving the collapse of bubbles in liquid. A colleague just forwarded the abstract of a peer-reviewed paper on this topic in one of the journals of The American Physical Society. The experimenters are directly addressing the concerns of other scientists who are questioning their earlier results.

The process in this case involves bombarding a bath of acetone and deuterium (heavy hydrogen) with sound waves and neutrons. The authors of the paper report finding evidence of nuclear reactions in the fluid--flashes of light, neutron emissions, and tritium (even heavier hydrogen)--that don't occur when they perform the same experiment on a bath containing only acetone.

This is pretty exciting stuff, even though Fleischman and Pons claimed similar evidence for their cold fusion experiments. As always, the proof rests on whether the results are repeatable, not just by the same team but by other researchers using their own apparatus, and if all extraneous influences, such as gamma rays from space, can be ruled out.

The implications for successful nuclear fusion at low temperatures and with fairly simple equipment would be profound, including all the benefits of large-scale fusion, plus the ability to provide them on a distributed basis without large central generating plants. This is a story I plan on following, with an appropriate degree of skepticism.