Assessment of new ex-vessel magnetic measurements in JET

A new ex-vessel magnetic diagnostics was installed in JET during the 2005 shutdown with the objectives of (i) providing experimental data for better modeling of the iron in the axisymmetric codes for plasma equilibrium reconstruction and (ii) testing the reliability of direct field measurements from Hall probes. The latter is of great interest for future ITER-like devices, where long lasting flat top phases are expected, in a high neutron yield and a high temperature environment. The experimental data achieved during the restart phase were analyzed with the aid of simulation codes. Each individual signal was assessed for inclusion in the general JET diagnostics system. The system is ready for use in the 2006 experimental campaigns.