Equilibrium theory of toroidal magnetic cusp confinement with internal circulation

Plasma confined in the Tormac configuration can be made to rotate about the minor axis so that guiding-center drifts do not carry the particles to the boundary layer even in a purely toroidal field B (R). In this way the anisotropy in velocity space caused by losses at the cusps will not be rapidly communicated to the interior. Rotation can be enhanced and controlled, in principle, by neutral injection with angular momentum about the minor axis. The properties and stability characteristics of such a state are theoretically investigated in the present paper. The conditions for a stationary state are shown to require that the number of particles on a flux tube remains constant, yielding the relation n (R) R/B (R) approx. = const. The equilibrium properties of the plasma are observed with the use of two different models: (1) The plasma is treated as consisting of two fluids with negligible centrifugal effects and interspecies interactions, where electrons are considered as isotropic with the equation of state d/dt (P/sube/n-/sup gamma/) =0, while the ions are anisotropic and obey the Chew--Goldberger--Low equations. (2) The plasma is treated as a single fluid with negligible centrifugal effects and scalar pressure, i.e., obeys d/dt (Pn-/sup gamma/) =0. In each case the equilibrium solutions n (R) are found to be marginally interchange-stable