Development of a Simulator for Plasma Position and Shape Control in JT-60SA

A simulator has been developed to control the position and shape of plasmas. It consists of an equilibrium solver and an “isoflux" controller. The equilibrium solver identifies an equilibrium under the specified poloidal field (PF) coil current and incorporates the effect of eddy currents. The plasma position and shape are obtained as a result of the equilibrium calculation by an introducing the imaginary magnetic field. The controller enables the simulation of the control of the position and shape using the isoflux technique and optimizes the control logic of the coil current in JT-60SA. It also controls the PF coil currents such that the poloidal flux remains equal at all specified locations. The simulation of the control of the position and shape in response to prescribed changes in the configuration, internal parameters, poloidal beta, and internal inductance is demonstrated. The transition from a limiter to a divertor configuration is also simulated.