Current reversal equilibrium configurations in the alternating-current operation of tokamaks

The equilibrium configurations with central current density reversal and those with two oppositely flowing current components on the high-field side and low-field side have been numerically modeled by using the exact solution of the Grad-Shafranov-Helmholtz equation, with the parameters chosen according to the tokamak alternating-current operation experiments. The modeling results (the magnetic flux surface configurations, the current density profiles, the plasma pressure, and the loop voltage) agree well with the experimental observations.