With historic explosion, a long sought fusion breakthrough
National Ignition Facility achieves net energy “gain” with laser-powered approach
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National Ignition Facility achieves net energy “gain” with laser-powered approach
More energy out than in. For 7 decades, fusion scientists have chased this elusive goal, known as energy gain. At 1 a.m. on 5 December, researchers at the National Ignition Facility (NIF) in California finally did it, focusing 2.05 megajoules of laser light onto a tiny capsule of fusion fuel and sparking an explosion that produced 3.15 MJ of energy—the equivalent of about three sticks of dynamite.
“This is extremely exciting, it’s a major breakthrough,” says Anne White, a plasma physicist at the Massachusetts Institute of Technology, who was not involved in the work.
Mark Herrmann, who leads NIF as the program director for weapons physics and design at Lawrence Livermore National Laboratory, says it feels “wonderful,” adding: “I’m so proud of the team.”
The result, announced today by officials at the U.S. Department of Energy (DOE), represents a shot in the arm for fusion researchers, who have long been criticized for overpromising and underdelivering. Fusion holds the tantalizing promise of plentiful, carbon-free energy, without many of the radioactive headaches of fission-driven nuclear power. But getting hydrogen ions to fuse into helium and release energy requires temperatures of millions of degrees Celsius—conditions that are hard to achieve and sustain. The NIF result shows it is possible, at least for a fraction of a second. “Three MJ is a hell of a lot of energy. It shows something is working,” says plasma physicist Steven Rose of Imperial College London.
Despite the fanfare, fusion power stations are still a distant dream. NIF was never designed to produce power commercially. Its primary function is to create miniature thermonuclear explosions and provide data to ensure the U.S. arsenal of nuclear weapons is safe and reliable. Many researchers believe furnacelike tokamaks are a better design for commercial power because they can sustain longer fusion “burns.” In a tokamak, microwaves and particle beams heat the fuel and magnetic fields trap it. “The challenge is to make it robust and simple,” White says.
However, the leading tokamak device, the ITER reactor under construction in France, is anything but simple. It is vastly over budget, long overdue, and will not reach breakeven until the late 2030s at the earliest. With NIF’s new success, proponents of such laser-based “inertial fusion energy” will be pushing for funding to see whether they can compete with the tokamaks.
