US government scientists have achieved net energy gain in a fusion reaction for the second time, a result likely to fuel optimism that progress is being made towards the dream of limitless, zero-carbon power.
Physicists have since the 1950s sought to harness the fusion reaction that powers the sun, but until December no group had been able to produce more energy from the reaction than it consumes — a condition also known as ignition.
Researchers at the federal Lawrence Livermore National Laboratory in California, who achieved ignition for the first time last year, repeated the breakthrough in an experiment on July 30 that produced a higher energy output than in December, according to three people with knowledge of the preliminary results.
您已阅读21%（746字），剩余79%（2742字）包含更多重要信息，订阅以继续探索完整内容，并享受更多专属服务。