Physicists Gave Up on This Fusion Technique in the 1980s. Now It’s Working

Key Points:

• Physicists at the DIII-D National Fusion Facility have successfully demonstrated helicon current drive, an old theoretical method from the 1980s that uses high-frequency radio waves to generate internal electric currents in fusion plasma for stabilization.
• Helicon current drive aims to overcome the intrinsic pulse length limitations of tokamak reactors, which currently rely on transformer-driven plasma currents and cannot operate continuously in a steady state, a requirement for commercial viability.
• Previous attempts in the 1980s failed due to insufficiently reactor-like plasmas, inefficient wave-launching technology, and inadequate diagnostic tools, but advances in reactor equipment and measurement techniques have now enabled successful experiments.
• The recent experiments used a specialized antenna to launch helicon waves into hot plasma, resulting in observable plasma heating and current generation, though further research is needed to increase power coupling and replicate reactor-like conditions.
• While promising, helicon current drive remains in early experimental stages, and its practical application in fusion reactors will require continued development over the coming years.