A novel path to fusion ignition: Heat first, then add fuel

What happened

For more than 70 years, fusion energy researchers have used a particular equation to judge whether a plasma would stay hot and dense enough—for long enough—to reach a point where it could sustain itself without any more external power added. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL) maps a path to ignition conditions using far less energy than any other path.