It was only for a fraction of a second, but still an important step toward clean energy generation. Researchers at the National Ignition Facility at Lawrence Livermore National Lab in California have succeeded in triggering a fusion reaction. Using 192 lasers and three times the temperature of the sun's center, two hydrogen molecules fused together generating energy with no waste. Preliminary data from the experiment had been released in August. On Wednesday, the journal Nature published the full results.
The fusion reached 1.5 quadrillion watts. The energy is released when hydrogen atoms fuse into helium, the same process that occurs in stars. In all, four experiments were performed with the participation of more than one hundred scientists.
The researchers' distant goal is to generate energy in the same way that the sun generates heat, with hydrogen atoms so close together that they fuse into helium.
According to the scientists, they are close to achieving an even greater breakthrough: ignition. This occurs when fuel burns on its own, producing more energy than is needed for the initial reaction.
In August, Mark Herrmann, deputy director of Livermore's program for fundamental weapons physics, compared the fusion reaction to the 170 quadrillion watts of sun rays that reach Earth. "It's about 10 percent of that," he said at the time. "The fusion energy emanated from a hot spot equivalent to the size of a human hair."
The explosion - basically a miniature hydrogen bomb - only lasted 100 trillionths of a second. Still, it generated optimism in scientists who had long hoped that it might someday provide a clean, unlimited source of energy. The reactions were surprising because fusion requires such high temperatures and pressures that it easily fails.
Siegfried Glenzer, a scientist at SLAC National Accelerator Laboratory in California who led the first fusion experiments at the Livermore facility years ago, said he was excited. "That's very promising, achieving an energy source that doesn't emit CO2."