Implementation of a consistent fluid‐neutral model in SOLPS‐ITER and benchmark with EIRENE

Abstract

In the quest for computationally affordable plasma edge transport simulations of reactor‐relevant plasmas, we consider fluid‐neutral models in this paper. To obtain good agreement with kinetic‐neutral models in charge‐exchange dominated regimes, model equations, transport coefficients, and boundary conditions have to be derived consistently from the kinetic description. In this paper, we describe a fully fluid plasma edge transport model that is aimed at reproducing the results of coupled finite‐volume/Monte Carlo runs with the kinetic Monte Carlo code EIRENE as closely as possible. To this end, we incorporate the rate coefficients from the AMJUEL reaction database, and boundary conditions are based on the reflection data from TRIM. The fluid‐neutral model is implemented into the SOLPS‐ITER code suite to compare the plasma sources with those of EIRENE on a simplified slab geometry. For a detached case, the results show a nearly perfect match between the fluid and kinetic model, with errors locally ranging up to a maximum discrepancy of 10% for particle and electron heat sources and 30% for parallel momentum sources. These very localized errors can be largely attributed to the discretization error, mainly near the ionization peak.