CURRENT REVERSAL IN TOKAMAK AND MAGNETIC-FIELD REVERSAL IN TOROIDAL PINCH UPON PLASMA TURBULENT RELAXATION

The process of plasma turbulent relaxation in magnetic confinement systems is considered. A family of finite states, accessible due to this process, was found. They correspond to Lyapunov's functional minima and involve the reversal of either the longitudinal current or the toroidal magnetic field at the periphery. It is shown that the functional extremum stability can be verified in the linear approximation using the Arnol'd's theorem concerning the frozen-in vector-field space stratification into equal-vorticity sheets. A comparison with experiment is accomplished. The possibility of maintaining the toroidal current in tokamak-type relaxed states by means of the bootstrap-effect is demonstrated.