Identification of Vertical Instabilities in the JET Tokamak

This paper deals with the electromagnetic aspects related to a series of experiments aimed at the identification and control of vertical instabilities in the JET Tokamak. The first part of the work is devoted to model the transient magnetic fields produced by the poloidal field circuits and the plasma edge localized modes (ELMs). The second part describes the approach used to design an ELM independent plasma speed estimator. The design of the estimator had to be developed with the constraint of using the present controller parameters, so as to minimize the impact on JET operation.