The JET magnet power supplies and plasma control systems

During a Joint European Torus pulse, the main tokamak loads (the toroidal coils, the transformer coils, the plasma equilibrium coils, and the additional heating devices (not described in this work)) require a total amount of energy of 10 000 MJ and a peak power in excess of 1000 MW. Since the tokamak loads require a direct-current (dc) supply, the alternating-current power from the energy sources is converted into dc by a combination of thyristor bridges (static units for the plasma position and shaping control, for the additional heating devices, and partially for the toroidal coils) and diode bridges. The ohmic heating circuit modulates the flow of power from the flywheel generator to the transformer coils, and its duty is to establish and control the plasma current. The plasma position and current control is made up of a feedback system built in a conventional way.