SOLPS modeling of neutral effects on pedestal structure during pellet fueling*

SOLPS-ITER has been used to model a set of discharges with the neutral particle source location varied from being dominantly external with an external gas puff for fueling and ECH for particle-free core heating, to being dominantly internally sourced with pellet fueling and NBI heating. Pellet fueling is modeled as a constant neutral source in the pedestal region where pellet ablation is observed. The discharges with core pellet and NBI fueling show increased pedestal density and an increase of over 30\% in the ratio of the pedestal to separatrix density. Modeling shows that all cases have similar particle confinement in the steep-gradient region of the pedestal, but moderate pellet fueling increases particle diffusion from the no-fueling case and decreases electron thermal transport inside $\psi_{N}$ of 0.9. Higher fueling leads to increased electron thermal transport in the steep gradient region for all cases due to increased convective flow. Ion charge exchange momentum loss is increased by a factor of 4 across the entire pedestal with external fueling as compared to core fueling. The inclusion of $\nabla$B drift effects results in an inward flux of particles for all cases, significantly altering the neutral deposition profile.