Physicists Made a Major Breakthrough in Fusion Reactor Development

When it comes to clean power alternatives, some like it hot.

Really hot.

And an experimental nuclear fusion reactor called the Wendelstein 7-X stellarator just took a substantial step toward providing clean, limitless energy by harnessing the power of atomic fusion, according to a recent study published in the journal Nature.

In case you missed it, society could soon begin to create plasma that’s twice as hot as the center of our sun.

Nuclear fusion at twice the temperature of the sun’s core

The new “major advance” announced by physicists involves ongoing efforts to confront energy losses inherent in the design of the experimental Wendelstein 7-X nuclear fusion technology. Stellarators are distinct in comparison to the more conventional, symmetrical, and donut-shaped tokamak fusion reactors, because the former employ maddeningly complex structures full of labyrinthine twists and turns. But like all other nuclear fusion reactors, the aim is to generate conditions one could only “see” (and then instantly die) from inside the mass of the sun. This is executed by subjecting plasma streams to unconscionable heights of pressure and temperature, leaving atoms no alternative but to collide and fuse with one another, producing unprecedented amounts of usable energy.

Understandably, the Wendelstein 7-X reactor is so overwhelmingly complex that only supercomputers could have designed it, which is why it uses a series of 50 superconductive magnetic coils to hold plasma in place as it’s looped around a spiraling circular chamber. Back in 2018, physicists at work on this project broke new energy density records, in addition to plasma confinement for this kind of fusion reactor. The groundbreaking experiments also heated plasma to extremely high temperatures of 36 million °F (20 million °C), far exceeding temperatures of the sun, at 27 million °F (15 million °C). And the Wendelstein 7-X could be capable of even higher temperatures, if you can believe it.

Nuclear fusion reactors remain a window into the future of clean energy

The engineering behind this advanced technology was organized to tackle one persistent barrier to fully-functioning capability, one unique to stellarator designs: A kind of heat loss dubbed “neoclassical transport.” This happens when collisions between heated particles push some out of their proper orbit, leading some to stray out of the magnetic field. And, in the Wendelstein 7-X, the magnetic field cage was specifically designed to avoid this tricky energy loss problem. But to confirm that the engineering came through, scientists at the Princeton Plasma Physics Laboratory (PPPL) and the Max Planck Institute for Plasma Physics carried out a novel evaluation of the stellarator’s groundbreaking experiments. This involved an emphasis on diagnostic data gathered via X-ray imaging crystal spectrometers, which revealed a substantial drop in neoclassical transport.

This means that the high temperatures witnessed by the physicists would not have been possible if the heat loss had happened. So it worked. “This showed that the optimized shape of the W7-X reduced the neoclassical transport and was necessary for the performance seen in W7-X experiments,” said Novimir Pablant, a physicist at PPPL, in a New Atlas report. “It was a way of showing how important the optimization was.” In other words, this record-breaking success means the Wendelstein 7-X is physically capable of confining heat that can soar to temperatures twice that found in the sun’s core. But there’s still much work to be done, including confronting other pesky heat loss issues. More experiments will go forward in 2022, including a novel water-cooling system that will enable longer experimental durations, but, for now, nuclear fusion remains an indispensable window into the future of clean energy production.