Fusion energy is suddenly flush with cash. Troy Carter knows that won’t be enough

Oak Ridge’s director of fusion energy explains why the global race to build the world’s first fusion plant still depends on hard physics and a little humility. The plasma physicist Troy Carter leads the U.S. fusion energy program at Oak Ridge National Laboratory. It’s one of science’s hottest and most humbling pursuits: trying to understand plasma, the superheated, electrically charged gas at the heart of stars—and, since the 1950s, every hydrogen bomb test and fusion experiment.