Numerical simulation of the reversed field pinch dynamo effect in the quasilinear, mean field equilibrium limit

In this paper numerical simulations are presented of the reversed field pinch (RFP) dynamo effect utilizing the resistive magnetohydrodynamic (MHD) equations in the quasilinear approximation. In addition, a mean field equilibrium magnetic field configuration is constructed in cylindrical geometry by dropping inertia on the symmetric radial component of the velocity field. Results are obtained for a variety of operating conditions: flat-top current, current ramp-up, and ramp-down. It is found that the Alfven time, although present in the equations describing the perturbed quantities, is not important on the long resistive run time; the result is a three-dimensional Ohmic equilibrium with symmetric mean toroidal magnetic field reversal. Using these results, and in view of recent RFP experimental data, a simple correspondence between global MHD behavior in the RFP and the tokamak is given