SOLPS-ITER modeling of Globus-M2 edge plasma with gradual density profiles in the pedestal region and small ELMs

A typical H-mode discharge of spherical tokamak Globus-M2 was simulated with SOLPS-ITER transport code with a kinetic description of neutral particles. It is demonstrated that the pedestal transport barrier is practically absent. Simulation results are in good agreement with the experimental profiles measured at the equatorial midplane, divertor probe data, and the results from divertor Thomson and helium monitor diagnostics. A small edge-localized mode (ELM) event was simulated using the dynamic mode of the SOLPS-ITER code, in which the time derivatives are treated physically—rather than as mere numerical relaxation parameters as in the standard steady-state mode—enabling the resolution of fast transient phenomena, such as the release of a large amount of plasma into the scrape-off layer, observed during ELM events. Simulation results for both inter-ELM and intra-ELM periods are consistent with observations obtained with available Globus-M2 diagnostics.