Design of the new RFX equilibrium active control system

The RFX new load assembly is characterized by a thin copper shell with a 50 ms time constant for the penetration of the vertical magnetic field. Since the time constant is shorter than the pulse length, an active control system is necessary to assure the plasma horizontal equilibrium. The design has been carried out by applying to the RFPs, the classical method developed for ITER and used for recent upgrades of presently operating tokamak devices. The design procedure is presented in the paper along with the results of closed loop simulations performed by linear and non-linear models.