Advanced MHD mode active control at RFX-mod

A new control scheme, named Clean Mode Control (CMC) and based on the real-time correction of the aliasing of the sideband harmonics produced by the saddle coils, brought about a significant improvement of RFX-mod discharges, allowing the routine operation at 1.5 MA plasma current. A refinement of the electromagnetic model of the system is in progress by integrating new experimental measures and “virtual” measures provided by CARIDDI code. A Multi Input-Multi Output (MIMO) pseudo-decoupler control system was designed and the promising results of numerical simulations suggested starting its real-time implementation. A simplified MIMO decoupler in the mode space, based on a model retaining only the largest cross-coupled mode, is also being developed.