Coupling plasmas and 3D passive structures in the JET tokamak

The impact of the 3D effects on the dynamic response of the plasma in the JET tokamak is assessed on the time scale of interest for plasma magnetic control and stabiliza tion. These effects are due to the limbs of the magnetic circuit and to the eddy currents in the 3D metallic structures. The plasma behaviour is taken into account by a specific matrix of modifi ed inductances interacting with the remaining part of the syst em via a virtual coupling surface.