A technique that some scientists claim generates thermonuclear fusion in a benchtop apparatus works even without its controversial neutron trigger. So say the researchers who, since 2002, have reported that nuclear-fusion reactions can occur in a vat of chilled solvent agitated by ultrasound (SN: 3/6/04, p. 149: Available to subscribers at http://www.sciencenews.org/articles/20040306/fob5.asp). If this method of sparking fusion proves to be valid—a big if, critics insist—it could lead to a remarkably simple, cheap, inexhaustible power source. Fusion reactions take place in the vat because clusters of bubbles form and then violently collapse, explains nuclear engineer and team leader Rusi P....