Plasma containment and stability theory

Abstract

Models of the behaviour of high temperature plasma are applied to the problem of plasma confinement in magnetic traps. A wide variety of possible instabilities is disclosed. In magnetic mirror traps the low frequency instabilties can be overcome by design of the magnetic field. The high frequency instabilities, particularly those associated with the loss-cone character of the equilibrium distribution function, are more persistent and appear to impose severe restrictions on the dimensions of the plasma. Consequently toroidal traps seem to offer a better prospect for long-term containment but at present they are subject to low frequency instabilities which persist even when conditions for hydromagnetic stability have been met. These instabilities may be due to small resistive effects or to an unstable drift wave. The resistive instabilities should disappear at high temperature and the drift-wave in­stability should be overcome by increased shear in the magnetic field.