Finite element electromagnetic analysis of the jet error field correction coils

In order to design the power supply and the control system of a new set of coils for controlling and studying the error field of the magnetic configuration of the JET machine, detailed electromagnetic analyses have been carried out. The system consists of four ex vessel coils whose primary objective is to compensate or vary both the amplitude and phase of the (m=2, n=1) harmonic error field. Results of the electromagnetic analyses in the foreseen operating frequency range, performed by means of both analytical and finite element codes, are reported and discussed. The efficacy of the system is evaluated by computing the magnetic field generated by the new correction coils. The calculation of the electrical parameters of the coils, taking into account the eddy current effect, is also reported.