Self-consistent modeling of highly-collisional plasma interacting with electrodes*

Lifetime issues of plasma-facing components (PFCs) in magnetic plasma confinement devices are one of major challenges on the way to sustainable fusion reaction. The PFCs need to withstand interaction with hot plasma gas, electron and ion bombardment and radiation. Liquid metal self-healing PFCs are a promising pathway to achieve long-lasting facilities. A multi-functional code was developed on a base of 3D CFD code ANSYS CFX which was substantially extended and customized. (i) MHD flow of liquid metal [1] with a free surface in a coplanar magnetic field was modeled. (ii) Electric arcs were modeled [2] in 1D and 2D. Heat transfer in non-equilibrium plasma was coupled to solution in the electrodes accounting for multiple surface effects, such as electron emission, ion recombination, radiation, ablation and space-charge sheaths. Electrode ablation rate agreed well with experimental data. (iii) Flow of ionized gas in a model MHD power generator with transversal magnetic field was simulated. Electric current was modeled throughout the plasma, electrodes and external load.

[1] A. Khodak et al., IEEE Trans. on Plasma Sci. 45, 2561 (2017).

[2] A. Khrabry et al., Phys. Plasmas 25, 013521 (2018)