The crux of the breakthrough is a magnet, but not just any magnet. The scientists created a new type of magnet that broke the world record for magnetic field strength, according to MIT News. Made from a high-temperature superconducting material, the magnet has a strength of 20 tesla. (For reference, a common refrigerator magnet is around 0.001 tesla, while the incredibly strong magnets used in MRI machines are 3 tesla.)
One of the steps that allowed the scientists to create such a ridiculously powerful magnet was the elimination of insulation around the layers of material used to form the device. This was, apparently, an outside-the-box idea in the world of super-magnet creation.
While clean, renewable energy sources such as wind and solar tend to own a larger share of the headlines, there is a big push among the scientific community to look toward fusion as the power source of the future.