Magnetohydrodynamic Modeling of Shattered Pellet Injection and Impurity Dynamics

Future tokamaks require disruption mitigation to prevent machine damage. Predictive models are needed to project these systems to future devices. We present an overview of disruption-mitigation modeling with the M3D-C1 MHD code. M3D-C1 has been coupled to a coronal model for impurities and a state-of-the-art model for pellet ablation. A 3D benchmark with NIMROD for an injected pellet shows that the codes agree on the peak radiated power as well as thermal-quench (TQ) and current-quench time scales, giving confidence in predictive modeling by both codes. Simulations of JET with realistic SPI plumes of pure-Ne and Ne-D2 pellets show a competition of time scales between pellet propagation and outside-in radiative collapse. At low injection speeds, the two pellets have similar TQ dynamics; at high speeds, the mixed pellet travels further before complete TQ. Other topics considered include single vs. dual-symmetric injection on KSTAR, validation of DIII-D SPI TQ modeling with experiment and EFIT reconstructions, predictive ITER simulations in L- and H-modes, and a comparison of coronal and collisional-radiative impurity models for disruption mitigation.