A model-based technique for integrated real-time profile control in the JET tokamak
This paper describes a new technique which has been implemented on the JET tokamak to investigate integrated real-time control of several plasma profiles simultaneously (such as current, temperature and pressure) and reports the results of the first experimental tests. The profiles are handled through their projection on a suitable basis of functions according to the Galerkin scheme. Their response to three actuators (heating and current drive powers injected in the plasma) is linearized in an experimentally deduced multi-input multioutput model. The singular value decomposition of this model operator allows us to design a distributed-parameter real-time controller which maximizes the steady state decoupling of the multiple feedback loops. It enables us to control several coupled profiles simultaneously, with some degree of fuzziness to let the plasma evolve towards an accessible non-linear state which is the closest to the requested one, despite a limited number of actuators. The first experiments using these techniques showthat different current and electron temperature profiles can be obtained and sustained by the controller during a closed-loop operation time window. Future improvements and perspectives are briefly mentioned.
Bibliographic Reference: An article published in: Plasma Physics and Controlled Fusion, Vol. 47 (2005) p. 155-183
Availability: This article can be accessed online by subscribers, and can be ordered online by non-subscribers, at: stacks.iop.org/PPCF/47/155
Record Number: 200517921 / Last updated on: 2005-02-24
Original language: en
Available languages: en