From profile to sawtooth control: developing feedback control using ECRH/ECCD systems on the TCV tokamak

Real time control of heating systems is essential to maximise plasma performance and avoid or neutralise instabilities under changing plasma conditions. Several feedback control algorithms have been developed on the TCV tokamak that use the electron cyclotron (ECRH/ECCD) system to control a wide range of plasma properties, including the plasma current, shape, profiles as well as the sawtooth instability. Controllers have been developed to obtain sawteeth of a pre-determined period, to maximise the sawtooth period using an extremum seeking control algorithm and finally to provide simultaneous control of the plasma emission profile peak and width using multiple independent EC actuators. Pacs numbers. 52.50.Sw 52.55.-s 52.55.Fa 52.55.Tn 52.55.Wq 07.05.Dz Submitted to. Plasma physics and controlled fusion