Magnetohydrodynamic Simulation of Pulsed Poloidal Current Drive in Reversed Field Pinch Plasmas

Abstract

Numerical simulations using magnetohydrodynamic (MHD) equations are performed for the pulsed poloidal current drive (PPCD) in reversed field pinch (RFP) plasmas. The PPCD is simulated by reducing the toroidal magnetic field at the wall, B_z(a), in the short period. The simulations take into account the values of reduced B_z(a), the period of changing B_z(a) and the start time as the characteristic parameters of the PPCD. The effects of the parameters on m=1 resistive modes, which play the main role in the sustainment of RFP configurations, are calculated. The PPCD has stabilizing effect for the m=1 modes over a wide range of the parameters. The dependence on the parameters for the formation of quasi-single helicity after the PPCD and for the growth of the m=0 mode is calculated. The stabilizing factor due to the enhanced magnetic shear for the resistive modes is also analyzed by the linear growth rate in the equilibrium model of the transient configuration during the period of the PPCD.