tokamak

1. (nuclear physics) A torus-shaped chamber used in nuclear fusion research in which a plasma is magnetically confined.Examples: "Studies of electrodeless discharges in a strong longitudinal magnetic field, carried out on the stellarator and the "Tokamak", have shown that in such systems the plasma becomes unstable for currents appreciably les than the critical current of Shafranov-Kruskal."; "A Tokamak engineering test reactor (TETR) will be an important component of any national or international program to achieve viable Tokamak fusion power reactors."; "Of magnetic fusion experiments, those in Tokamaks are closest to achieving the combination of confinement conditions needed for a reactor."