Tokamak cOntrol of plasma Radial profiles in Infinite Dimensional setting – TORID

The TORID project (Tokamak cOntrol of plasma Radial profiles in Infinite Dimensional setting) aims at bringing together teams of researchers in feedback control, applied mathematics and plasma physics in order to make a significant step forward on a key issue in magnetic fusion control research : the control of 1D distributed plasma profiles in the so called tokamak facilities. Feedback control of the main macroscopic plasma parameters is now quite well mastered in the different worldwide tokamaks, but the control of plasma radial profiles, in particular the so-called safety factor profile, is still in its infancy, whereas it now appears to be crucial in order both to ensure safe operation and to sustain high performance regimes. This issue will have a direct impact on the success of the key world project in the domain, ITER, that is presently under construction in Cadarache, in the South of France, but also to reduce the size and cost of future fusion reactors. The specific target of this project with respect to the state of the art is : (a) to develop control approaches in infinite dimensional setting in view of potential benefit in terms of better handling of non linear couplings and physics model uncertainties as compared to previously developed finite dimensional approaches; (b) to implement the resulting advanced control algorithms on the French Tore Supra tokamak which, due to its capability to run long lasting plasma discharges, offers a unique opportunity to develop and test plasma safety factor profile control schemes on relevant time scales. The scientific and technical programme will follow a staged approach with four tasks of increasing complexity : (1) Task 1 will aim at testing on real experiments some preliminary control algorithms, based on a reduced reference model featuring one single Partial Differential Equation (resistive diffusion of the magnetic flux) and a reduced set of control inputs, that were recently designed by the Partners under the framework of pre-existing collaborations; (2)Task 2 will aim at extending the approach to a more comprehensive / consistent model, including the couplings to a second Partial Differential Equation (heat transport equation), taken in its steady state limit to begin with, as justified by the ordering or corresponding time scales; (3) Task 3 will aim at a complete handling of the two coupled PDEs without the previous assumption; (4)Task 4 will finally aim at studying the possibility to apply the previously developed methods to fusion burn control that will also bring into play the coupling between PDEs (heat and particle transport equations). Each of these 4 tasks will be supported by activities in 4 fields of expertise as brought by the Partners, namely control oriented modelling, control law design, Partial Differential Equation parameters estimation and integration of the previous activities either on numerical simulations or on real experiment on the Tore Supra tokamak.