Moving toward mass-conserving simulations of plasma turbulence and kinetic neutrals in the tokamak boundary with the GBS code

What is it about?

This work reports on the development of a mass-conserving self-consistent model for the neutral-plasma interaction in the tokamak boundary, using GBS, a 3D fluid turbulence code. The improvements required to make the model mass-conserving are described, including the changes implemented within the plasma model, neutral model and boundary conditions. The impact of the improvements are discussed, as well as the first results from mass-conserving simulations and the general trends observed when varying the plasma density.

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Photo by HalGatewood.com on Unsplash

Photo by HalGatewood.com on Unsplash

Why is it important?

This work highlights the importance of implementing geometry consistently in both the plasma and neutral models to achieve mass conservation, as well as proper boundary conditions to ensure mass is conserved when considering recycling at the boundary. The publication highlights the impact of each of these changes in the simulation. The effect of increasing the plasma density in the simulation is also analyzed, as the ionization source shifts from the edge to the region around the LCFS.