Transient microwave heating of compact toroidal plasmas

A heating scheme using radio-frequency (rf) power to heat a compact torodial plasma to kilovolt temperatures using lower hybrid heating is proposed. The scheme requires the use of high-power pulsed klystrons. The experimental design is shown with the details of the rf power system and of the coupling antenna array. The so-called 'radiation barrier' formed by the presence of oxygen and carbon impurities may be crossed by this type of pulsed heating source. The general atomic physics of this heating phase is described, with particular emphasis on the non-local thermodynamic equilibrium effects involved in the line and recombination impurity radiation. A survey of nonlinear parametric coupling effects is also given.