Numerical analysis of a coupled problem: time-evolution of a tokamak plasma in contact with a conducting wall.

In this paper we analyse the time evolution of a tokamak plasma after the failure of the vertical control system. In this case, the plasma eventually touches the conducting wall and gives rise to currents which flow partly in the wall, partly in the plasma. We show how, under simplifying assumptions, the problem can be analysed by means of pure electromagnetic formulations. After a brief review of the state of the art in the analysis of this phenomenon, we propose and discuss three alternative Eulerian approaches: an evolutionary equilibrium formulation, convection-diffusion model and a 3D error-based approach