'We actually made a lot of progress in the last year.' Steady improvements in the lasers, targets, and other components gradually put the facility in a position where it could finally generate energy from the capsule.

Herrmann says that the August 2021 shot gave the team a starting point. More out than inĮven after last-year's achievement, there was still one more goal to reach – producing more power from the tiny capsule than the lasers put in. Such tests will make sure that new and refurbished parts of nuclear weapons behave as expected. In addition, he says the radiation from the explosions can be used to test components. 'We use these experiments to get experimental data to compare to our simulations,' says Herrmann, who also oversees nuclear weapons research at the lab. The data from these tiny explosions are fed into complex computer simulations that help physicists understand whether the nation's nuclear weapons remain reliable, despite decades on the shelf. The United States has not tested a nuclear weapon since 1992, and the primary purpose of the NIF facility is to conduct very small-scale bangs that closely mimic nukes. This self-burning ignition actually resembles a process similar to that of a modern thermonuclear warhead, albeit on a much smaller scale. 'You start with a little spark, and then the spark gets bigger and bigger and bigger, and then the burn propagates through.' Bang in a box The process is analogous to lighting gasoline, says Riccardo Betti, the chief scientist of the laboratory for laser energetics at the University of Rochester. Then in August 2021, after years of slow but steady progress, physicists were able to ignite the hydrogen inside the capsule, creating a self-sustaining burn. The result is nuclear fusion, the process that powers the Sun and the world's largest nuclear weapons. The facility uses powerful lasers to compress fuel pellets.

Nuclear vs fusion vs fission