THE PHYSICS OF MAGNETIC FUSION-REACTORS

During the past two decades there have been substantial advances in ma gnetic fusion research. On the experimental front, progress has been l ed by the mainline tokamaks, which have achieved reactor-level values of temperature and plasma pressure. Comparable progress, when allowanc e is made for their smaller programs, has been made in complementary c onfigurations such as the stellarator, reversed-field pinch and field- reversed configuration. In this paper, the status of understanding of the physics of toroidal plasmas is reviewed. It is shown how the physi cs performance, constrained by technological and economic realities, d etermines the form of reference toroidal reactors. A comparative study of example reactors is not made, because the level of confidence in p rojections of their performance varies widely, reflecting the vastly d ifferent levels of support which each has received. Success with the t okamak has led to the initiation of the International Thermonuclear Ex perimental Reactor project. It is designed to produce 1500 MW of fusio n power from a deuterium-tritium plasma for pulses of 1000 s or longer and to demonstrate the integration of the plasma and nuclear technolo gies needed for a demonstration reactor.