Number 377 (Story #2), June 17, 1998 by Phillip F. Schewe and Ben Stein|
BEST ALPHA HEATING YET IN A TOKAMAK. At the Joint European Torus (JET, a huge donut-shaped vessel 9 m across) in England, the hydrogen isotopes deuterium and tritium are heated until they fuse, creating a helium-4 ion (also called an alpha particle) and a neutron. The ultimate goal, for a fusion reactor, is to render the neutron's energy into usable electricity, while the alpha's energy would be turned back into the plasma as a form of self-heating. Recent tests at JET have clearly observed the alpha self-heating at work: up to 10% of the plasma heating came from alphas and resulted in an increase in plasma temperature (P.R. Thomas et al., upcoming article in Physical Review Letters; firstname.lastname@example.org). JET had a good year in 1997, establishing several records for fusion experiments: 21 MJ of fusion energy, 16 MW peak power, and 65% of input power turned into fusion output power.