TL;DR
A power station has to run all day, every day, and the most studied fusion machine, the doughnut-shaped tokamak, naturally runs in pulses. A team working on the DIII-D machine in San Diego now reports the first experimental evidence that radio waves beamed in from outside can push the electric current that holds a tokamak's plasma together, the job that would let such a machine run steadily instead of in bursts. The push was small: about 20,000 amps, give or take 10,000, out of roughly 1 million, a slice of about 2%. Its own authors call it proof of principle at modest power. Still, it turns a long-proposed idea for future fusion plants into something that has actually been measured, and that is one more piece of the path toward fusion power that never has to stop.
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