Development of a feedback system to control MHD instabilities in ASDEX Upgrade

An automatic feedback control system (FCS) is presently being developed for the tokamak ASDEX Upgrade. The FCS will be used to control and/or suppress magneto-hydro-dynamic instabilities, in particular neoclassical tearing modes and sawteeth, using its new, multi-frequency, electron cyclotron heating system, which allows the on-line fast steering of the poloidal injection angle. The FCS is conceived to couple with different time scales. The general features, strategy and first tests for a reliable controller are presented. (C) 2007 Elsevier B.V. All rights reserved.