The Helically Symmetric Experiment, or HSX, is the only fusion device in the world that has a magnetic field structure described as Quasi-Helically Symmetric (QHS), which allows excellent confinement properties.

HSX is an optimized stellarator with coils arranged in a torus-like configuration. Its magnetic field confines high-temperature plasma with temperatures higher than 10 Million degree C. HSX is part of the UW– Madison mission to establish a fusion power plant that produces commercialized energy.