The effects of the stellarator windings located on the large-major-radius side of the tokamak are studied experimentally. The strong focussing effect provided by the stellarator field significantly improves positional stability.
The collisional-radiative model is applied to a recombining hydrogen plasma in order to find the plasma state in which the population inversion between the ground state and the first excited state can be generated. The population inversion is expected in a plasma where the three body recombination has a large contribution to the recombining processes and the effective recombination rate is beyond a certain value for a given electron density and temperature. Calculated results are presented in figures.
An idea is suggested which leads to a significant reduction in the required number of toroidal field coils and to a dramatic improvement in access for tokamak maintenance and diagnostics. It is found that a two or four coil system may be practical. The basic concept is presently being used for designing RST (Radio Frequency Driven, Steady-State Tokamak) of General Atomic Company.