ABSTRACT
Heating of plasmas in tokamaks and other similar machines used in research into controlled nuclear fusion is a major use of very high power microwave and radiofrequency sources. The basic heating method in a tokamak, which is a toroidal device with the hot plasma contained by a magnetic field, is through the current which flows around the plasma. However, this Ohmic heating becomes less effective as the temperature goes up, since the plasma resistivity scales as T-3/2, and some form of auxiliary heating is needed to get to the temperatures required, which correspond to particle thermal energies of the 10–20 keV. Heating with high power electromagnetic waves is one such method (the other being injection of high power neutral beams) which has been used successfully in most large tokamak experiments.
