Conceptual design of the enhanced radial field amplifier for plasma vertical stabilisation in JET

This paper presents a design for a new power supply, named enhanced radial field amplifier (ERFA), for the vertical stabilization of the plasma column in the JET machine. The aim is to increase the performance compared with the fast radial field amplifier (FRFA, in operation at JET since the early 1990s) and to control the plasma in the new demanding scenarios that will be produced in JET after the EP2 enhancement phase. After discussing the performance required of ERFA, the paper describes the specific solution identified and illustrates the main criteria followed for the design of the system, highlighting the specific choices and the motivations behind them.