RESISTIVE MAGNETOHYDRODYNAMIC EQUILIBRIA IN A TORUS

It was recently demonstrated that static, resistive, magnetohydrodynam ic equilibria, in the presence of spatially uniform electrical conduct ivity, do not exist in a torus under a standard set of assumed symmetr ies and boundary conditions. The difficulty, which goes away in the '' periodic straight cylinder approximation,'' is associated with the nec essarily non-vanishing character of the curl of the Lorentz force, jxB . Here, we ask if there exists a spatial profile of electrical conduct ivity that permits the existence of zero-flow, axisymmetric resistive equilibria in a torus, and answer the question in the affirmative. How ever, the physical properties of the conductivity profile are unusual (the conductivity cannot be constant on a magnetic surface, for exampl e) and whether such equilibria are to be considered physically possibl e remains an open question. (C) 1997 American Institute of Physics.