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Journal of Physical Studies 16(1/2), Article 1903 [11 pages] (2012)
DOI: https://doi.org/10.30970/jps.16.1903 NON-LTE FORMATION OF THE SI I 1082.7 nm LINE IN ONE- AND THREE-DIMENSIONAL MODELS OF THE SOLAR ATMOSPHEREA. V. Sukhorukov
Main Astronomical Observatory, NAS of Ukraine, |
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The formation of the Si\,I 1082.7\,nm line in several one-dimensional (1D) semi-empirical models and a three-dimensional hydrodynamical (3D HD) model of the solar atmosphere were studied. Significant departures from LTE were found in all the models. These departures are due to the line formation height shift and the line source function deficit. In the 3D model, the non-LTE line core intensity is much lower than those in the 1D models, if inelastic collisions with hydrogen atoms are neglected. In the 3D model a good agreement with observations can be obtained if the Drawin formula with a scaling factor $S_{\mathrm H} = 0.1$ is used to describe such collisions in order to compensate for strong non-LTE effects. In the 1D models, which do not describe the effects of real atmospheric ihnomogeneities, the best-fit is obtained with a higher value $S_{\mathrm H} = 1$. The best-fit oscillator strength $\log {\mathit gf}$ was estimated for this line. It is about $0.27$ in the 1D models, and $0.24$ in the 3D model.
PACS number(s): 95.30.Jx, 95.30.Ky, 96.60.Mz