Feasibility study and CXRS synthetic diagnostic model for COMPASS upgrade based on Cherab and Raysect framework

In this article the forward model and feasibility study of the CXRS (Charge Exchange Recombination Spectroscopy) diagnostic for the COMPASS Upgrade tokamak [1] based on the Raysect and Cherab framework [2–4] is presented. The neutral beam model available in Cherab is expanded and based on individual acceleration grid beamlets. The spatial density distribution calculation takes into account 3D geometry of the port structure. Beam density profile calculated with the expanded model is used to estimate realistic radial resolution of measurement and to produce forward models of the spectra. Effects of background plasma and beam halo are not included. The spectra are used to reconstruct the plasma profiles and are compared with the simulation input to estimate measurement errors with respect to positions of collecting optics.