Critical<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>β</mml:mi></mml:math>for Toroidal Equilibrium

Abstract

Toroidal, ideal magnetohydrodynamic equilibrium, with magnetic surfaces enclosing a single magnetic axis, is possibly for arbitrary $\ensuremath{\beta}$ (plasma pressure/poloidal magnetic pressure). When $\ensuremath{\beta}$ exceeds about one-half the aspect ratio, the toroidal current reverses on the inner edge of the plasma. The poloidal current balances the pressure gradient.