Axisymmetric dynamic simulation of a plasma disruption coupled with a 3-D eddy current code

Abstract

A two dimensional magnetohydrodynamic plasma model is presented and coupled to an existing three dimensional eddy current code which computes the currents and forces induced in the plasma facing components of a tokamak. In order to simplify the coupling to the finite element based eddy current code for the electromagnetic part of the plasma model a finite element method is applied. The fluid dynamic part is solved with a volume of fluid (VOF) technique which was modified to account for the preservation of the toroidal magnetic flux. This technique allows an easy and accurate tracking of the plasma boundary, which is important for the detection of the plasma-wall contact. Furthermore, the scraping-off of the outmost plasma layer and the retarding effect of the toroidal halo currents on the plasma motion are modelled. With this coupled code, a given initial equilibrium state and a rough guess of the temperature profile and evolution, a representative ASDEX Upgrade disruption including a vertical disruption event (VDE) is simulated successfully. The computation time needed for this coupled analysis is comparatively short.