Computation and experimental validation of the transfer functions of the local control coil system in RFX

The transfer functions required for the design of the RFX local control system of the field error at the shell gap were obtained from harmonic magnetic analysis performed by the Finite Element (FE) Method. Comparisons with experimental data, obtained in pulses with and without plasma, are reported in the paper. Closed loop operation of a prototype coil showed the system capability to vanish the field radial component on the outer surface of the shell.