NUMERICAL ANALYSIS OF EDDY CURRENTS AND MAGNETIC FORCES IN THE VACUUM VESSEL OF ASDEX UPGRADE

The magnetic field diffusion through the toroidal vacuum vessel of the ASDEX Upgrade tokamak that occurs on sudden disruption of the plasma current is numerically investigated. The ring-shaped plasma in the single-null configuration considered here occupies an asymmetric position in the vessel. The FEDIFF code, which is based on the finite-element network method, is used to calculate the time behaviour and distribution of the eddy currents in the vessel wall. The vessel is permeated by magnetic fields, which act with the eddy currents to exert forces. The distribution of the maximum forces in the vessel wall and the reactions of the support due to the asymmetric position of the plasma were also analyzed.