A 10-year plan presented last week to the federal Fusion Energy Sciences Advisory Committee... calls for the Department of Energy (DOE), the main sponsor of U.S. fusion research, to prepare to build a prototype power plant in the 2040s that would produce carbon-free electricity by harnessing the nuclear process that powers the Sun. The plan formalizes a goal set out 2 years ago by the National Academies of Sciences, Engineering, and Medicine and embraced in a March report from a 15-month-long fusion community planning process. It also represents a subtle but crucial shift from the basic research that officials in...