Using the world's largest laser, the researchers coaxed fusion fuel for the first time to heat itself beyond the heat they zapped into it, achieving a phenomenon called a burning plasma.
Unlike burning fossil fuels or the fission process of existing nuclear power plants, fusion offers the prospect of abundant energy without pollution, radioactive waste or greenhouse gases.
US government scientists said on Wednesday they have taken an important step in the long trek toward making nuclear fusion - the very process that powers stars - a viable energy source for humankind.