Non-Maxwellian toroidal equilibria with spheroidal plasma--vacuum interfaces

Axially symmetric toroidal plasma equilibria with spherical or near-spherical plasma-vacuum boundaries are examined when variations in the distribution function produce anisotropic pressures. A separable analytic solution is found when the pressure deviation from isotropy is small; the degree of anisotropy is used as an expansion parameter in the perturbation scheme. In general, the plasma-vacuum boundaries deform slightly and spherical boundaries cannot be maintained by externally applied fields that remain finite at large distances. When p⊥>p‖, the plasma becomes a prolate spheroid and when p‖<p⊥ it becomes oblate.