Edge plasma turbulence simulations in detached regimes with the SOLEDGE3X code

Abstract

Experimental results from several tokamaks suggest a strong impact of divertor density regimes on turbulent transport in the edge plasma. Reciprocally, the change in cross- field transport and Scrape-Off-Layer (SOL) width affects the access to density regimes, making it a fundamental topic for heat exhaust issue. Addressing this issue self- consistently requires numerical modeling tools including, both, turbulent transport and neutrals recycling physics. In this study, the SOLEDGE3X multi-fluid edge plasma code is used to conduct a first analysis of turbulent transport in a long-leg diverted plasma in high density regimes. A fluid neutrals model is used to model particle recycling as well as fueling by gas puff. A dedicated pulse run in the TCV tokamak is modeled in which a density scan from attached to detached plasma conditions was performed. The following results demonstrate the achievement of a turbulence simulation in the detached regime, explicitly highlighting a change in turbulence properties between low and high density, which are responsible of a change in the SOL widths.