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

Laboratoire d'Astrophysique de Toulouse-Tarbes, Université de Toulouse, CNRS, 14 av. E. Belin, 31400 Toulouse, France e-mail: [lleger;fpaletou]@ast.obs-mip.fr

Received: 30 May 2008
Accepted: 24 January 2009

Abstract

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  Å  and D₃ multiplets, which can be directly compared to the simultaneous and high-resolution observations completed at THéMIS. A preliminary 2D multi-thread modelling is also discussed.