2D non-LTE radiative modelling of He I spectral lines formed in solar prominences

Context. The interpretation of high-resolution spectropolarimetric observations of solar prominences completed primarily at visible and near-infrared wavelengths, requires radiative modelling that takes into account both multi-dimensional geometry and complex atomic models. Aims. We enhance the interpretation of observations of He I multiplets, by considering 2D non-LTE unpolarized radiation transfer, and taking into account of the atomic fine-structure of helium. Methods. We apply our 2D non-LTE radiative transfer code, which is based on the multi-grid Gauss-Seidel/SOR iterative schemes. Results. It allows us to compute realistic emergent intensity profiles for the He I lambda 10 830 angstrom and D-3 multiplets, which can be directly compared to the simultaneous and high-resolution observations completed at THeMIS. A preliminary 2D multi-thread modelling is also discussed.