THE M3D-C1 CODE AS A TOOL FOR DESIGN VALIDATION AND WHOLE-DEVICE MODELING
Nathaniel M. Ferraro · OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) · 2024
Recent developments, new applications, and future directions with the M3D-C1 code that extend its use for tokamak and stellarator design validation are summarized.M3D-C1 is a parallel, implicit, finite element code that provides the capability to simulate MHD equilibrium and stability by combining a three-dimensional, nonlinear fluid plasma model with a variety of models for sources, impurities, transport, and external conductors.A new meshing capability now enables the efficient treatment of multiple conducting regions, such as the nested vessels in ITER and SPARC.These regions allow anisotropic, non-axisymmetric resistivity, and spatially-resolved descriptions of eddy currents and halo currents.Building on the recent implementation of a non-equilibrium impurity radiation and transport model in M3D-C1, simulations of disruption mitigation in NSTX-U, DIII-D, ITER, and SPARC yield detailed predictions of thermal and electromechanical loads.Furthermore, a new fluid model for runaway electrons allows self-consistent evolution of the runaway electron beam and the MHD stability of the plasma.A new capability to model non-axisymmetric spatial domains has also been implemented, enabling simulations of strongly-shaped stellarators, including W7-X and LHD.This model self-consistently describes the breakup of magnetic surfaces and the effect on the pressure profile as the plasma is heated.Finally, the capability to apply M3D-C1 to a set of varied model equilibria to map peeling-ballooning stability thresholds has been demonstrated.Taken together, these capabilities provide a unique new tool for high-fidelity design validation and wholedevice modeling.