Researchers at the Department of Energy’s Princeton Plasma Physics Laboratory are using a stellarator they designed and built using permanent rare-earth magnets and a 3D-printed shell to help test new fusion power concepts. MUSE—the first stellarator built at PPPL in 50 years—took one year to construct and generated its first plasma in February 2023. The work that went into its design has already inspired a stellarator power plant concept being developed by a commercial spin-off, Thea Energy.