Self‐consistent coupling of the three‐dimensional fluid turbulence code TOKAM3X and the kinetic neutrals code EIRENE

Abstract

The three‐dimensional (3D) turbulence code TOKAM3X‐EIRENE, coupling the 3D non‐isothermal version of TOKAM3X to the EIRENE Monte Carlo solver has been developed with the ability to simulate self‐consistently the interactions between large‐scale flows and turbulence both in limited and diverted plasmas, including recycling. This is especially important for diverted plasmas, where neutrals play a key role and where the recycling source is strongly dominant. The code package relies on the same interface as the Soledge2D‐EIRENE code, which retains state‐of‐the‐art plasma–wall interaction, as well as atomic and molecular physics. In this paper, we present the first results obtained in WEST divertor geometry, in laminar mode, with the aim of verifying the new code package. The divertor density regimes are recovered, and the code results are shown to be consistent with the results of the two‐point model, thus opening the way for turbulent simulations.

Global fluid simulations of edge plasma turbulence in tokamaks: a review

“…There is a wide variety of models based on either fluids or kinetic equations, depending on the expected accuracy and computational cost. However, while edge transport codes have for long included neutrals dynamics, edge turbulence modelling has only recently started addressing the topic and many open questions subsist in terms of numerical implementation and physics [57,58,59].…”

“…In turbulence simulations, the first attempt to couple a 3D turbulence code with EIRENE was carried out in Ref. [58]. The model was not extensively exploited since due to its high computational cost.…”

“…Indeed, a hierarchy of neutrals models have to be considered ranging from advanced fluid models to full kinetic ones in order to find the best compromise between fidelity and computing cost. These models could be directly embedded in the codes (for examples en [57]) or via codes coupling to EIRENE [58] as it is currently done in transport codes (see below).…”

The GBS code for the self-consistent simulation of plasma turbulence and kinetic neutral dynamics in the tokamak boundary

“…The first three-dimensional turbulent simulation of the SOL with the self-consistent evolution of a kinetic neutral model was carried out by using GBS in limited geometry [31]. Recently, the three-dimensional turbulence code TOKAM3X has been coupled to the EIRENE code to simulate plasma turbulence and kinetic neutrals in a diverted geometry [48].…”

The effect of divertor particle sources on scrape-off-layer turbulence

“…In this 'high-recycling' regime, the neutral dynamics become more important, as the ionisation acts as a large particle source and the radiation provides an additional energy sink to the system. The full study of plasma and neutral interaction is a very complex problem, and it is challenging to simulate the whole process in realistic tokamaks [5,[16][17][18][19][20]. We could adopt non-self-consistent sources to speed up the calculations.…”