Daniel Clery in Science Mag

FOOTHILL RANCH, CALIFORNIA—In a suburban industrial park south of Los Angeles, researchers have taken a significant step toward mastering nuclear fusion—a process that could provide abundant, cheap, and clean energy. A privately funded company called Tri Alpha Energy has built a machine that forms a ball of superheated gas—at about 10 million degrees Celsius—and holds it steady for 5 milliseconds without decaying away. That may seem a mere blink of an eye, but it is far longer than other efforts with the technique and shows for the first time that it is possible to hold the gas in a steady state—the researchers stopped only when their machine ran out of juice.

“They’ve succeeded finally in achieving a lifetime limited only by the power available to the system,” says particle physicist Burton Richter of Stanford University in Palo Alto, California, who sits on a board of advisers to Tri Alpha. If the company’s scientists can scale the technique up to longer times and higher temperatures, they will reach a stage at which atomic nuclei in the gas collide forcefully enough to fuse together, releasing energy.

“Until you learn to control and tame [the hot gas], it’s never going to work. In that regard, it’s a big deal. They seem to have found a way to tame it,” says Jaeyoung Park, head of the rival fusion startup Energy/Matter Conversion Corporation in San Diego. “The next question is how well can you confine [heat in the gas]. I give them the benefit of the doubt. I want to watch them for the next 2 or 3 years.”

Although other startup companies are also trying to achieve fusion using similar methods, the main efforts in this field are huge government-funded projects such as the $20 billion International Thermonuclear Experimental Reactor (ITER), under construction in France by an international collaboration, and the U.S. Department of Energy’s $4 billion National Ignition Facility (NIF) in Livermore, California. But the burgeoning cost and complexity of such projects are causing many to doubt they will ever produce plants that can generate energy at an affordable cost.