Gyrokinetic Simulation of the Edge in LTX-β Using Gkeyll in 1 and 2 Dimensions

Lithium coated plasma-facing walls can significantly reduce plasma recycling, yielding an operating regime with a hot edge and essentially flat temperature profiles in the core. Lithium-coated walls are studied in the Lithium Tokamak Experiment (LTX-β), a tokamak with a 40 cm major radius, 0.3 T toroidal field and $I_p=135$ kA. In order to establish a connection between the flat temperature profiles with a hot edge and a reduction in wall recycling, we require estimates of the plasma fluxes to the wall. Most scrape-off layer (SOL) simulations use fluid models that are not rigorously valid in the hot, collisionless interior of LTX-β. Furthermore, they may lack important mirror trapping effects that can affect the plasma profiles in this region. We therefore employ the gyrokinetic solver in the Gkeyll code to study the SOL, carrying out 1D simulations to understand the parallel dynamics and the impact of mirror forces in the LTX SOL. We compare these 1D simulations with adiabatic electron simulations, and also discuss 2D simulations which we employ to study the impact of drifts and to provide better initial conditions for 3D simulations. This work can help us better understand properties of a lithium-walled machine and improve our ability to predict its performance in the future.