2D and 3D Simulations of Neutral Particle Fluxes from Plasma Recorded by Neutral Particle Analyzer at the L-2M Stellarator

2D and 3D simulations of the penetration of neutral particles into the plasma with parameters corresponding to the ohmic heating regime in the L-2M stellarator were performed, and the simulation results were compared. Radial distributions of neutrals density in plasma and model energy spectra of fluxes of charge-exchange atoms escaping from the plasma were obtained. For the conditions of the ohmic heating regime in the L-2M stellarator, the limiting plasma densities were determined, above which it is necessary to take into account the recombination processes when performing simulations. Comparison of the model energy spectra of fluxes of charge-exchange atoms escaping from the plasma with experimental data made it possible to construct the radial distributions of the neutrals density in absolute units. In this case, the calculated density of neutrals at the plasma axis turned out to be ~10¹⁵ m^–3, which is four orders of magnitude less than the density of charged particles 10¹⁹ m^–3.