New heights in fusion power.

On May 27, researchers at the Princeton University Plasma Physics Laboratory achieved record levels of controlled fusion power. Using a magnetically confined plasma made up of a half-and-half mixture of deuterium and tritium, the Tokamak Fusion Test Reactor (TFTR) generated a burst of 9 million watts of power, besting the previous record of 6.2 million watts established last December at the same facility (SN: 1/1/94, p.12). The new power level was maintained for 240 milliseconds. The plasma temperature reached 460 million kelvins.

The sequence of experiments leading to this record furnished additional evidence that energetic alpha particles created by the fusion of deuterium and tritium nuclei deposit energy into the plasma and increase its temperature (SN: 5/28/94, p.341). The existence of this effect improves the prospects of eventually obtaining a self-heating plasma, a crucial step toward commercial fusion power.

Researchers will try to reach at least 10 million watts before the TFTR is shut down and dismantled, an operation scheduled to start at the end of September to make way for an advanced fusion reactor known as the Tokamak Physics Experiment. The new reactor is designed to generate fusion power continuously rather than in bursts.