The physics of magnetic fusion reactors

Abstract

Once ignition has been achieved the physics problems of the tokamak reactor differ from those considered hitherto which have mainly concerned stability, confinement and heating. The reacting plasma must be controlled and optimized through a cycle that comprises start-up, burn and shut-down phases. Efficient methods are required for extracting the thermonuclear energy which is deposited as heat within the plasma, for injecting fresh D-T fuel, for extracting the ash and impurities, for protecting the wall of the combustion chamber and for preventing contamination of the plasma. The most difficult problems appear to be concerned with radiation damage, low power density and the complex topology and large size of reactors currently being designed.