Plasma corners. II: Arbitrary profiles

Ordinary plasma corners are studied in two-dimensional magnetohydrostatic equilibria with arbitrary axial current density profiles. The corner structure depends only on the nearby current density profile and the multiplicity of the magnetic stagnation point. A simple corner, for instance, is right-angled if the current density is bounded at the separatrix or diverges more slowly than any power of the poloidal magnetic flux, but is acute-angled or even cusped otherwise. As an application, the magnetohydrodynamic interchange stability criterion is shown to be violated near simple corners in Z-pinch equilibria