Abstract of JORSTAR Project

The dynamics of large scale plasma instabilities can strongly be influenced by the mutual interaction with currents flowing in conducting vessel structures. The relevance of a resistive wall model is directly evident for Resistive Wall Modes (RWMs) or Vertical Displacement Events (VDEs). However, also most other large-scale instabilities may be influenced significantly by the interaction with wall currents. With this in mind, the non-linear finite element MHD code JOREK has been coupled with the resistive wall code STARWALL, which allows to include the effects of eddy currents in 3D conducting structures in non-linear MHD simulations. The codes are currently being extended to halo currents.

JOREK-STARWALL has already been applied to non-linear simulations of RWMs, VDEs, disruptions triggered by massive gas injection, and Quiescent H-Mode. It has the potential to contribute to the understanding of fundamental physics questions regarding many types of large-scale plasma instabilities, the interpretation of related experimental observations, and predictions for ITER. Since MPI parallelization is currently lacking in STARWALL and also in the coupling terms in JOREK, it is not possible to resolve realistic wall structures with a large number of wall triangles due to the consumption of wall clock time and memory by STARWALL and by the coupling terms in JOREK.

The current project is required to address realistic wall structures which is of high interest to ITER (as demonstrated also by an ITER contract involving JOREK-STARWALL) since precise current patterns are required for the prediction of asymmetric forces acting on support structures during disruption events.