Newly-available superconducting materials like REBCO (a single-crystal material composed of yttrium, barium, copper, oxygen and other elements) allow the creation of unprecedentedly-high-field magnets. They may enable smaller and less-expensive versions of venerable tokamak-type fusion reactors (like the Alcator C-Mod, which was shuttered last year), in part because a doubling of magnetic field strength produces a 16-fold increase in fusion power density. Hartwig says a fast-track high-field magnet development program, followed by the possible building of a compact, net-energy-gain tokamak in the next 5-10 years, would be a watershed in dispelling fusion’s reputation as being always in the future.