Energy record set in magnetic fusion.

Taking another step along the long road to extracting energy from the fusion of atomic nuclei, researchers at the Princeton University Plasma Physics Laboratory last month achieved record levels of controlled fusion power. Using a magnetically confined mixture of equal parts of deuterium and tritium (heavy isotopes of hydrogen) as fuel, they generated more than 3 million watts of power in a burst lasting about 1 second. In subsequent tests, they raised the fusion reactor's output to more than 5 million watts.

The Princeton results handily beat the previous fusion power record of 1.7 million watts, set in 1991 at the Joint European Torus (JET) laboratory in Culham, England (SN: 11/16/91, p.308). Nonetheless, the Princeton reactor produced only about one-eighth as much energy as it required to create and maintain the high-temperature plasma of charged particles within which nuclear fusion takes place.

The experiments, conducted at the Tokamak Fusion Test Reactor, will continue through most of 1994. Researchers hope to reach a power output of 10 million watts, and they expect these investigations will yield data important for the design of future reactors. The reactor, contaminated with radioactive tritium, will be closed down and dismantled after the experiments are completed.