Simultaneous closed-loop control of the current profile and the electron temperature profile in the TCV tokamak

摘要

Two key properties that are often used to define a plasma operating scenario in nuclear fusion tokamak devices are the current and electron temperature (T) profiles due to their intimate relationship to plasma performance and stability. In the tokamak community, the current profile is typically specified in terms of the safety factor (q) profile or its inverse, the rotational transform (ι = 1/q) profile. The plasma poloidal magnetic flux (Ψ) and T dynamics are governed by an infinite-dimensional, nonlinear, coupled, physics-based model that is described by the magnetic diffusion equation and the electron heat transport equation. In this work, an integrated feedback controller is designed to track target ι (proportional to the spatial gradient of Ψ) and T profiles by embedding these partial differential equation models into the control design process. The electron thermal conductivity profile is modeled as an uncertainty, and the controller is designed to be robust to an expected uncertainty range. The performance of the integrated ι + T profile controller in the TCV tokamak is demonstrated through simulations with the simulation code RAPTOR by first tracking a nominal target, and then modulating the T profile between equilibrium points while maintaining the ι profile in a stationary condition.