Magnetohydrodynamic stability of flux-conserving tokamak equilibria

Large-scale magnetohydrodynamic instabilities of flux-conserving tokamak equilibria are studied computationally. Stable equilibria are found with up to 5% average ..beta... As ..beta.. is increased, the observed instabilities take on a strong ballooning character, concentrating near the outer edge of the torus with a mix of poloidal harmonics.