Most people these days have probably at least heard of fusion– a proposed way to generate electricity by using heat from nuclear fusion reactors, combining two atomic nuclei to form a heavier nucleus while releasing energy. While the concept has long remained the darling of science fiction and scientific research, it has of yet failed to bear fruit.
A research lab in Germany is working to advance fusion technology and evaluate the main components of a future fusion power plant in its development of the Wendelstein 7-X. This machine is a stellarator, the largest of its kind and costing over €1 billion. The strangely twisted device is a 16-meter-wide ring of metal studded with odd devices and mysterious cables that lead off in all directions.
Inside lies 50 6-ton non-planar and 20 planar magnetic coils which create a magnetic field that prevents plasma from colliding with the inside of the reactor. The plasma itself flows with a temperature of 60-130 megakelvin (10.8 to 23.4 billion degrees F; 60 million to 13 billion degrees C). The coils wind around a cooling device which creates enough liquid helium to cool down the magnets and their enclosure to 4 kelvin (-452° F; -269° C). Those are some extreme temperatures, to be sure.
While stellarators are expensive, hard to build, and may look like something out of a Dali painting, they do have their benefits. Once started, they should be able to run steadily and reliably and are not tormented by the potentially metal-bending magnetic disruptions of other fusion devices.
It is expected that the Wendelstein 7-X will be able to reach 30 minutes of continuous plasma discharge in 2021.