Pedestal fueling studies enabled by streamlined neutral transport workflow*

Due to the mean-free-path of atomic physics not directly scaling with the size of a device, larger devices are less efficient at refueling from recycling atoms [Mordijck, Nuclear Fusion 2020]. This phenomenon is demonstrated over a range of models with progressively responsive plasma physics, up to and including global gyrokinetic simulations. A scan over a wide variety of static pedestal parameters indicates what pedestal structures are likely to be most sensitive to atomic-plasma interaction. The impact of an edge gas puff is analyzed and optimized.

These studies are enabled by new user interfaces to the DEGAS2 neutral transport code. The capability for the user to adjust the plasma profile on-demand is demonstrated, as is the ability to incorporate modern tooling for collisional radiative modelling and plasma-material interaction. The prospect of using such workflows to build a database of neutral interaction profiles, incorporating neutral physics into optimization workflows, and analysis of synthetic diagnostics [Wilkie, et al. Nuclear Fusion 2024] is discussed.