SOLPS simulations of detachment in a snowflake configuration for the future upper divertor in ASDEX Upgrade

Abstract

We report on the first SOLPS simulations of a low-field side snowflake minus (LFS SF-) configuration in ASDEX Upgrade (AUG). This configuration will become accessible in AUG after the foreseen hardware modification of its upper divertor. Spatially constant transport coefficients, an input power of 5 MW and a nitrogen seeding rate leading to a radiative fraction of 86% were assumed. This radiative fraction is 9% higher than that for a single null reference with the same transport coefficients, similar upstream parameters and separatrix impurity concentrations. As a consequence the LFS SF- configuration achieves a larger degree of detachment and reduced heat fluxes to the targets. This heat flux mitigation was found to be significantly stronger than that expected from a simple scrape-off layer splitting model.