Helicon Current Drive Confirmed for Fusion Reactors

The successful tokamak experiment offers a new method to sustain steady-state conditions in fusion power plants.

Updated on Oct. 30, 2026 in Nuclear

Isometric editorial illustration of a metallic donut-shaped fusion reactor with a glowing plasma core inside a laboratory setting. — Researchers at the DIII-D facility in San Diego successfully demonstrated helicon current drive in a tokamak, marking a milestone for continuous fusion. AI Illustration. Upload story photo >

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Researchers at the DIII-D National Fusion Facility have successfully confirmed helicon current drive within a tokamak, a milestone for steady-state fusion reactor operation. The experimental results, which address a long-standing challenge in plasma physics, were published in Physical Review Letters.

Why it matters

Achieving steady-state tokamak operation is essential for the longevity of fusion reactors, as it prevents the structural degradation caused by cyclic stress in pulsed designs. This successful demonstration of current drive via helicon waves offers a potential path toward sustaining the necessary magnetic fields for continuous fusion.

The experiment utilized a comb line antenna to inject helicon waves into the plasma, successfully driving currents and demonstrating wave absorption. This method marks a departure from previous failures, though further testing at higher power levels is required to assess performance across regimes.

The players

DIII-D National Fusion Facility

A major magnetic fusion research center that operates one of the largest tokamaks in the United States.

Bob Pinsker

A researcher and joint first author of the paper who focuses on fusion plasma physics and current drive methods.

The details

The research team employed a comb line — a specialized antenna array designed to launch electromagnetic waves — to penetrate the high-temperature plasma. By absorbing these helicon waves, the plasma sustains the toroidal current required for magnetic confinement. This is a critical departure from pulsed operations, which induce fatigue in reactor materials. Researchers observed these driven currents using advanced measurement diagnostics, validating the feasibility of the mechanism after decades of experimental difficulty.

1980s: Researchers made initial attempts to demonstrate helicon current drive without success.
October 30, 2026: The peer-reviewed paper detailing the experimental confirmation was published.

The Tech Race

This development marks a significant shift from the limitations observed in the 1980s to a viable method for steady-state control. It positions helicon current drive as a potential alternative to other heating methods, such as those relying on high gyrotron counts in projects like STEP.

This research provides a fundamental capability update for fusion facility operators rather than an immediate change for consumers. Researchers are now tasked with increasing power levels to determine how this approach scales in different operational regimes.

The takeaway

The successful drive of plasma currents confirms that helicon wave injection is a viable mechanism for future steady-state fusion reactors. Researchers will now focus on scaling the power of these systems to determine the most effective configuration for long-term reactor reliability.