3D simulations of vertical displacement events in tokamaks: A benchmark of M3D-C${}^1$, NIMROD and JOREK

Abstract

In recent years, the nonlinear 3D magnetohydrodynamic codes JOREK, M3D-C${}^1$ and NIMROD developed the capability of modelling realistic 3D vertical displacement events (VDEs) including resistive walls. In this paper, a comprehensive 3D VDE benchmark is presented between these state of the art codes. The simulated case is based on an experimental NSTX plasma but with a simplified rectangular wall. In spite of pronounced differences between physics models and numerical methods, the comparison shows very good agreement in the relevant quantities used to characterize disruptions such as the 3D wall forces and energy decay. This benchmark does not only bring confidence regarding the use of the mentioned codes for disruption studies, but also shows differences with respect to the used models (e.g. reduced versus full MHD models). The simulations show important 3D features for a NSTX plasma such as the self-consistent evolution of the halo current and the origin of the wall forces. In contrast to other reduced MHD models based on an ordering in the aspect ratio, the ansatz based JOREK reduced MHD model allows capturing the 3D dynamics even in the spherical tokamak limit considered here.

References in corpus (4)

• The JOREK non-linear extended MHD code and applications to large-scale instabilities and their control in magnetically confined fusion plasmas
• Coupling JOREK and STARWALL for Non-linear Resistive-wall Simulations
• Understanding the reduction of the edge safety factor during hot VDEs and fast edge cooling events
• Simulations of COMPASS Vertical Displacement Events with a self-consistent model for halo currents including neutrals and sheath boundary conditions

Cited by in corpus (4)

• The JOREK non-linear extended MHD code and applications to large-scale instabilities and their control in magnetically confined fusion plasmas
• Complete 3D MHD simulations of the current quench phase of ITER mitigated disruptions
• Runaway electron deconfinement in SPARC and DIII-D by a passive 3D coil
• Nonlinear MHD simulations of external kinks in quasi-axisymmetric stellarators using an axisymmetric external rotational transform approximation