High Quality Content by WIKIPEDIA articles! ZETA, short for "Zero-Energy Toroidal (or Thermonuclear) Assembly", was a major experiment in the early history of fusion power research. It was the ultimate device in a series of UK designs using the Z-pinch confinement technique, and the first large-scale fusion machine to be built. ZETA sparked an intense national rivalry with the US`s pinch and stellarator programs, and as ZETA was much larger and more powerful than US machines, it was expected that it would put the UK in the lead in the fusion race.