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Late September, ITER Director-General Pietro Barabaschi is honoured with the 2024 Chinese Government Friendship Award in a ceremony in Beijing. This is the highest award granted by the People's Republic of China to foreigners who have made "outstanding contributions to the country's economic and social progress." Also pictured is fellow recipient Tony Donné (left), physicist and former head of EUROfusion, and WU Sha from the Hefei Institutes of Physical Science.

New results from the JET tokamak offer positive news for tokamak reactor designs based on deuterium-tritium fuel, according to the European Consortium for the Development of Fusion Energy, EUROfusion.

Reporting on experiments run in deuterium-tritium (DT) during JET's record-breaking campaign in 2021—and comparing them to control experiments performed in pure deuterium (DD)—EUROfusion researchers found that future fusion power plants using DT fuel may experience fewer energy losses in their burning plasma due to instabilities than previously anticipated.

"Our goal was to study whether our earlier findings on turbulence reduction in tokamak plasmas with high-energy ions could be replicated in DT plasmas, the primary fuel for the international ITER project and future fusion power plants," explain Jeronimo Garcia (CEA-IRFM, France) and Yevgen Kazakov (LPP-ERM/KMS, Belgium), the leading authors of a paper* published in Nature Communications.  

What they found in experiments that replicated ITER conditions as closely as possible was that, with tritium in the mix, core plasma conditions actually improved. They also observed "a new beneficial state" at the edge of the plasma, without unwanted energy bursts. "Our results demonstrate that the addition of heavier tritium ions has a calming effect on the plasma, reducing turbulence," says Garcia.

This is good news for ITER and future magnetic confinement fusion reactors. Alberto Loarte, head of the ITER Science Division, had this reaction: "The results in these studies show that there is better-than-expected performance in DT plasmas compared with DD plasmas; in particular, instabilities triggered by fast particles in DT plasmas such as those expected for fast helium produced by fusion in ITER can reduce energy losses from the plasma and increase fusion performance. The studies show that if instabilities remain at low levels they actually increase performance, whereas we had formerly assumed that they would most likely decrease it. The results also show that in conditions that are relevant to ITER, it might be possible to replace the intermittent burst of plasma energy through edge localized modes (ELMs) through a much more benign continuous outflow more easily handled by the wall in ITER."

See the original story on the EUROfusion website here.

*J. Garcia, Y. Kazakov et al., Nature Communications 15, 7846 (2024) https://doi.org/10.1038/s41467-024-52182-z

--Image: D-T plasma in JET pulse #99896, together with the computed zonal poloidal flows. Credits — plasma photo: UKAEA; flow calculation: FAR3D code