Fusion energy feels like a perpetually elusive goal, but with new ideas and better equipment, scientists have been inching closer to harnessing the power of the stars. But some physicists are testing a different combination: better equipment for an old idea.

Physicists recently reported the successful experimental demonstration of helicon current drive at the DIII-D National Fusion Facility. First proposed in the 1980s, helicon current drive uses a specific type of high-frequency radio wave to drive the hot plasma of a fusion reactor, producing an internal electric current to stabilize the reaction. However, the equipment at the time simply wasn’t able to deliver on the theory, which was why the idea was shelved until now. But thanks to major strides in reactor equipment, scientists tested and successfully demonstrated helicon current drive for the first time.

Physicists Bob Pinsker, Jeff Lestz, and Bart Van Compernolle of General Atomics were co-lead authors of the paper describing the results, published recently in Physical Review Letters.

Most leading fusion setups employ a tokamak, a donut-shaped machine that uses magnetic fields to confine plasma. One set of magnetic coils generates a toroidal field the long way around the donut, whereas a current-carrying magnet called a solenoid creates a second magnetic field the short way around the donut, according to an explainer by the U.S. Department of Energy.

However, as Pinsker explained to Gizmodo, the operational length of the tokamak is “intrinsically limited” in its duration—pulse length—as the plasma current is driven by a transformer-like arrangement.

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