Simulation Studies of Neon Pellets and SPI for Plasma Disruption Mitigation in Tokamaks

Numerical studies of the ablation of neon pellets and multiple pellet fragments in tokamaks in the plasma disruption mitigation parameter space have been performed using time-dependent pellet ablation models based on the front tracking code FronTier-MHD and the Lagrangian Particle code. Both codes use the same kinetic models for the electronic heat deposition, pellet surface ablation models, equations of state with multiple ionization support, and radiation models. The Lagrangian particle model is highly adaptive and capable of simulating a large number of fragments in 3D. The Lagrangian treatment of ablated material eliminates numerical difficulties of dealing with the tokamak background plasma. Both codes achieve good agreement with theory for spherically symmetric ablation flows. Simulations predict processes in ablation clouds and the dependence of pellet ablation rates on background plasma parameters and the magnetic field.