Coupled continuum gyrokinetic and kinetic neutral simulations in shaped scrape-off layer scenarios

Interactions between the plasma and neutral particles play a crucial role in determining the exhaust characteristics of tokamak plasmas, and magnetic shaping in the scrape-off layer (SOL) can have important effects as well. Thus, the coupling of a continuum full-f gyrokinetic turbulence model with a 6D continuum model for kinetic neutrals in the Gkeyll code has been extended to model shaped SOL scenarios. The neutral distribution function is evolved in non-orthogonal field-line following coordinates for the physical space and orthogonal coordinates for the velocity space. Geometric terms are applied via the streaming term in the Vlasov equation. This coupling is presented in seeded blob simulations with DIII-D SOL parameters. Magnetic shear and flux expansion decrease radial blob velocities by increasing poloidal blob velocities and shearing the blobs apart more quickly. Including neutral interactions can also decrease radial blob velocities while increasing blob coherence. Thus, it is important to include both magnetic geometry and neutral interactions to accurately model blob dynamics in gyrokinetic SOL simulations.