Effects of Anisotropic Thermal Conductivity in Magnetohydrodynamics Simulations of a Reversed-Field Pinch

A compressible magnetohydrodynamics simulation of the reversed-field pinch is performed includinganisotropic thermal conductivity. When the thermal conductivity is much larger in the direction parallel to the magnetic field than in the perpendicular direction, magnetic field lines become isothermal. As aconsequence, as long as magnetic surfaces exist, a temperature distribution is observed displaying a hotterconfined region, while an almost uniform temperature is produced when the magnetic field lines becomechaotic. To include this effect in the numerical simulation, we use a multiple-time-scale analysis, whichallows us to reproduce the effect of a large parallel thermal conductivity. The resulting temperaturedistribution is related to the existence of closed magnetic surfaces, as observed in experiments. Themagnetic field is also affected by the presence of an anisotropic thermal conductivity.