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Milne-Eddington inversions of the He I 10830 Å Stokes profiles: Influence of the Paschen-Back effect

The Paschen-Back effect influences the Zeeman sublevels of the He I multiplet at 10830 Å, leading to changes in strength and in position of the Zeeman components of these lines. We illustrate the relevance of this effect using synthetic Stokes profiles of the He I 10830 Å multiplet lines and investigate its influence on the inversion of polarimetric data. We invert data obtained with the Tenerife Infrared Polarimeter (TIP) at the German Vacuum Tower Telescope (VTT). We compare the results of inversions based on synthetic profiles calculated with and without the Paschen-Back effect being included. We find that when taking into account the incomplete Paschen-Back effect, on average 16% higher field strength values are obtained. We also show that this effect is not the main cause for the area asymmetry exhibited by many He I 10830 Stokes V-profiles. This points to the importance of velocity and magnetic field gradients over the formation height range of these lines.