Effect of resistivity on poloidal asymmetries in electron density in the edge and scrape off layer in 3D full-F gyro-fluid simulations with <scp>FELTOR</scp>

Abstract In this contribution, we analyze the poloidal asymmetries in electron density in the edge and scrape-off layer (SOL) in a COMPASS-sized, diverted tokamak with the 3D full-F, isothermal, electromagnetic, and gyro-fluid model FELTOR. The study is performed for different simulations that span over 2 orders of magnitude in resistivity. The poloidal asymmetries of density are evaluated in the edge and the SOL relative to the outer midplane (OMP), where the highest densities are usually found. In the closed magnetic surfaces, the relative poloidal asymmetry with respect to the OMP is not larger than 20% independently of the plasma resistivity. For the open field lines in the SOL, the relative density asymmetry can range from 55% for the highest resistivity to around 40% for the lowest. The lowest densities inside the separatrix are found between the inner midplane and the top of the magnetic configuration, away from the X-point. In the SOL it is usually close to the X-point in the high field side. The observations in the closed field lines are consistent with ballooning transport but in the SOL oppose experimental evidence for high-density plasmas. This indicates the necessity for more complex physics to reproduce the experimental observations in the SOL for higher density plasmas, such as neutral-plasma dynamics and realistic divertor conditions.