Current expectations for fusion power from toroidal machines

The rapidly increasing effort to solve the problems of the controlled release of nuclear fusion energy has been stimulated by recent maturation of the science of plasma physics, especially in one area -- the confinement of plasma in closed magnetic fields. At the same time, significant experimental progress has been achieved with magnetic mirror machines, and a large toroidal theta pinch is under construction at Los Alamos. Enthusiasm is running high in groups working on laser-ignited fusion. Perhaps all of these approaches will lead to viable power systems. It seems to be generally accepted, however, that toroidal magnetic machines have the greatest probabilit-y of being first if not the only approach to succeed, and this paper restricts its attention to that category. Current theories correspond to experimental results in the laboratory, and predictions of these theories imply the possibility of successful thermonuclear reactors. At the same time increasingly more realistic studies of hypothetical fusion power stations carried out by laboratory, university, utility, and manufacturing personnel make them appear to be potentially of great economic interest. Serious problems still remain, but increasing government support leads many to expect a scientific feasibility experiment and a demonstration of thermonuclear burning of deuterium-tritium fuel before 1980.