Preparation for the operation of ITER: EU study on the plasma control system

In view of the preparation for the operation of the ITER tokamak it is necessary to develop the plasmascenarios taking into account all engineering constraints coming from the plant and including a realisticcontrol system. It is important to consider that, due to the high energy of ITER plasmas, much morestringent requirements are posed on the control of transients in order to avoid machine damage.Several activities are performed in the EU focusing on one side on the scenario optimization from aphysics point of view and on the other side on the design and modeling of a realistic plasma controlsystem driving the plasma configuration throughout the whole pulse and suitable for implementationon a real machine.The issues related to the computation of the control feed-forward component are addressed. In par-ticular, the possibility to trigger a feed-forward component to solve controllability problems arising inthe transitions from plasma L to H and H to L modes is studied in detail with the support of linear andnon-linear simulations.A control strategy is designed and tested on non-linear simulations of the whole pulse, including linearand non-linear effects due to controller switching, plasma shape reconstruction and power supplies.The paper reports on the results of the studies performed and discuss the proposed design of the plasmacontrol system.© 2014 Published by Elsevier B.V.