Pressure limits of an axisymmetric torus

In order to clarify the pressure limit of a toroidal plasma equilibrium in a three-dimensional geometry, an azimuthally symmetric toroidal plasma was considered. In a tokamak-like plasma, the net toroidal current is necessary for a finite β plasma equilibrium. If external conductors are used to provide the rotational transform, iota, the plasma pressure is limited to β = (iota/2π)2/2A, where A is the aspect ratio