Zeta -
A torus-shaped reactor used in the mid-20th Century to carry out experiments in plasma physics and temperature controlled thermonuclear reactions.
Wikipedia
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. ZETA sparked an intense national rivalry with the US's pinch and stellarator programs, and as ZETA was much larger and more powerful, it was expected that it would put the UK in the lead in the fusion race.
