cold fusion or low-temperature fusion, nuclear fusion of deuterium, an isotope of hydrogen , at or relatively near room temperature. Fusion, the reaction involved in the release of the destructive energy of a hydrogen bomb , requires extremely high temperatures, and investigations of fusion as a possible energy source have focused on the problems involved in designing an apparatus to contain and sustain such a reaction (see nuclear energy ; nuclear reactor ). In 1989 B. Stanley Pons and Martin Fleischmann, chemists at the Univ. of Utah, announced that an experiment conducted at room temperature using platinum and palladium electrodes immersed in heavy water (deuterium oxide) had produced excess heat and other byproducts that they ascribed to a fusion reaction. Attempts to replicate their experiment produced initially conflicting results, but several early announcements of experimental confirmation were later retracted. Pons and Fleischmann were also later criticized for having skewed data to show the emission of gamma rays at an energy level typical of fusion.

Research into the possibility of low-energy nuclear reactions (as the field is also called) nonetheless continues, because of intriguing but inconclusive experimental results—such as claims of the production of excess heat, helium, or tritium where heavy water reacts with metals—and because of the desirability of producing relatively nonpolluting fusion energy in quantity at any temperature. Cold-fusion proponents believe that the fusion mechanism is different from that of "hot fusion" in that it encompasses some type of unusual nuclear reaction in the metal lattice involving deuterium and possibly other atoms. Several dozen models to explain the observed phenomena have been advanced, but none accounts for the full range of experimental observations.

Bibliography: See F. David Peat, Cold Fusion: The Making of a Scientific Controversy (1989); F. E. Close, Too Hot to Handle: The Race for Cold Fusion (1991); J. R. Huizenga, Cold Fusion: The Scientific Fiasco of the Century (1993); G. Taubes, Bad Science: The Short Life and Weird Times of Cold Fusion (1993).

COLD NUCLEAR FUSION

COLD NUCLEAR FUSION, an intensely disputed and largely discredited method for generating thermo-nuclear fusion at room temperature conditions. In nuclear fusion hydrogen atoms merge to form one helium atom, releasing energy. In its conventional form, such as that occurring within stars and hydrogen bombs, nuclear fusion requires high pressure and temperature, which force the atoms together. Proponents of cold nuclear fusion maintain that certain catalysts can coax hydrogen atoms to fuse without extreme pressure or heat. One form of cold nuclear fusion, known as muon-catalyzed cold fusion and first suggested in the 1940s, is undisputed. The process, in which a subatomic particle known as a muon captures two hydrogen atoms and forces them to fuse, has been demonstrated in the laboratory but appears not to be feasible as an energy source. The controversial form of cold nuclear fusion was first heard of in March 1989, when two University of Utah chemists, Martin Fleisch-mann and B. Stanley Pons, reported that they had produced fusion in a test tube at room temperature by running an electrical current through heavy water, a type of water in which the hydrogen atoms are of the isotope deuterium. They claimed that the current drove the deuterium atoms into a palladium rod in the water, forcing the atoms to pack closely enough to fuse. This announcement raised a furor in the scientific community. After other researchers failed to obtain similar results with the technique, a consensus emerged that the Utah scientists had used a flawed apparatus and misinterpreted the data from the experiment. A small but vocal minority of researchers continued to pursue variations on the approach.

BIBLIOGRAPHY

Huizenga, John R. Cold Fusion: The Scientific Fiasco of the Century. Rochester, N.Y.: University of Rochester Press, 1992.

Mallove, Eugene F. Fire From Ice: Searching for the Truth behind the Cold Fusion Furor. New York: Wiley, 1991.

VincentKiernan/a. r.

See alsoPhysics: Nuclear Physics ; Scientific Fraud .

cold fu·sion • n. nuclear fusion occurring at or close to room temperature. Claims for its discovery in 1989 are generally held to have been mistaken.