Comparison between measured divertor parameters in ASDEX Upgrade and SOLPS code solutions

Detailed modelling of the plasma edge of ASDEX Upgrade in Ohmic and H-mode discharges was performed with the SOLPS (B2-EIRENE) code. A tendency of the code solutions to underestimate the divertor Te and overestimate the plasma density (thus, predicting cooler and denser divertor than in the experiment) has been reliably established. A possible cause of the observed discrepancies is the presence of a significant population of supra-thermal ions and electrons in the SOL and divertor, which cannot be modelled by the fluid plasma code B2.