Simulation of surface currents excited by plasma Wall-Touching Kink and vertical modes in tokamak

Abstract

During plasma disruptions in tokamaks, electric currents are excited in the three-dimensional vessel structures by a plasma Wall Touching Kink Mode (WTKM). These modes are frequently excited during a Vertical Displacement Event (VDE) and cause big sideways forces on the vacuum vessel which are difficult to confront. To understand the plasma disruptions in tokamaks and to predict their effects, realistic simulations of these electric currents are required. In the present paper a flat triangle Finite Element (FE) representation of these surface currents excited in a thin conducting wall of arbitrary three-dimensional geometry is described. Our wall model covers both eddy currents, excited inductively, and source/sink currents due to current sharing between the plasma and the wall.