Two-dimensional non-linear model of reversed field pinch plasma evolution

A two-dimensional non-linear equilibrium code, able to simulate reversed field pinch (RFP) discharges, has been developed. It is based on the two-dimensional, finite element, MHD equilibrium code MAXFEA, which has been properly modified by introducing RFP profiles of the poloidal current density flux function in accordance with the µ&p model. In particular, equation parameters consistent with available data from the RFX machine have been used. A complete mesh of the RFX poloidal field system has been prepared and the whole poloidal electrical circuit has been implemented into the code. The RFP equilibrium code has been successfully validated against some RFX experiments, with and without plasma. Validation tests were performed using as inputs either the active coil currents or the converter voltages. On the basis of the positive results, the model was considered sufficiently reliable to describe RFX with the new load assembly, too.