Finite Beta Equilibria in Axially Symmetric Toroidal Plasma Containment Devices

Numerical methods are applied to solve the guiding-center fluid equations, with isotropic and anisotropic pressure, in an axisymmetric toroidal configuration. The shape and structure of equilibrium magnetic flux surfaces with arbitrary plasma beta and arbitrary toroidal curvature are calculated. A comparison with the vacuum magnetic fields shows that for some pressure distributions the plasma markedly distorts the magnetic field. For other distributions the magnetic mirror instability limits the maximum allowable plasma beta. It is also found that with isotropic pressure the maximum allowable beta is much higher than with slightly anisotropic pressures.