Reaction of the toroidal resistive wall on the magnetic field variations in tokamak-like systems

Abstract

The study is devoted to the problem of the magnetic field diffusion through a toroidal resistive shell (wall with respect to the interior). This is the same task as that considered in Dialetis et al. [J. Appl. Phys. 69, 1813 (1991)], but with a new element: current-carrying plasma inside the vessel. This extends the study on tokamaks with a resistive wall. The shape and position of the magnetically confined plasma must react on the field variations which brings considerable complications in the plasma electromagnetic description as compared to that of the rigid wall and external conductors. The proposed algorithm is devised so that the plasma properties are fully accounted for. It is based on the Green's function technique providing correct asymptotic behavior of the solutions that determine, through Maxwell equations and Ohm's law, the current induced in the wall during transient events. For tokamaks, this gives a closure in the analytical approaches incorporating the plasma-wall electromagnetic interaction with non-ideal wall reaction. This is needed for disruption modeling and, in particular, for evaluation of the disruption forces on the wall in large tokamaks like ITER with expected plasma current quench from 15 MA to zero in 35 ms.