Spectropolarimetric analysis of an active region filament. II. Evidence of the limitations of a single component model

Abstract

Our aim is to demonstrate the limitations of using a single component model to study the magnetic field of an active region filament. For that we have analyzed the polarimetric signals of the He I 10830 A multiplet acquired with the infrared spectrograph GRIS of the GREGOR telescope (Tenerife, Spain). After a first analysis of the general properties of the filament using Hazel under the assumption of a single component model atmosphere, in this second part we focus our attention on the observed Stokes profiles and the signatures which cannot be explained with this model. We have found an optically thick filament where the blue and the red components have the same sign in the linear polarization as an indication of radiative transfer effects. Moreover, the circular polarization signals inside the filament show the presence of strong magnetic field gradients. We have also shown that even a filament with such high absorption still shows signatures of the circular polarization generated by the magnetic field below the filament. The reason is that the absorption of the spectral line decays very quickly towards the wings, just where the circular polarization has a larger amplitude. In order to separate both contributions, we explore the possibility of a two component model but the inference becomes impossible to overcome as a high number of solutions is compatible with the observations.

8 pages, 11 figures, accepted for publication in A&A

References in corpus (11)

• Advanced Forward Modeling and Inversion of Stokes Profiles Resulting from the Joint Action of the Hanle and Zeeman Effects
• The magnetic field configuration of a solar prominence inferred from spectropolarimetric observations in the He I 10830 A triplet
• Influence of atomic polarization and horizontal illumination on the Stokes profiles of the He I 10830 multiplet
• Multicomponent He I 10830 Å profiles in an active filament
• The Dynamics of Funnel Prominences
• Vector magnetic field measurements along a cooled stereo-imaged coronal loop
• Spectro-polarimetric Imaging Reveals Helical Magnetic Fields in Solar Prominence Feet
• Multi-line Stokes inversion for prominence magnetic-field diagnostics
• Spectropolarimetric analysis of an active region filament. I. Magnetic and dynamical properties from single component inversions
• Upper Chromospheric Magnetic Field of a Sunspot Penumbra: Observations of Fine Structure
• Inference of magnetic fields in inhomogeneous prominences

Cited by in corpus (11)

• Critical Science Plan for the Daniel K. Inouye Solar Telescope (DKIST)
• Stokes Inversion based on Convolutional Neural Networks
• Determining the dynamics and magnetic fields in He I 10830 Å during a solar filament eruption
• Magnetic Structure of an Erupting Filament
• High flow speeds and transition-region like temperatures in the solar chromosphere during flux emergence
• The role of the chromospheric magnetic canopy in the formation of a sunspot penumbra
• Magnetic Field of Solar Dark Filaments Obtained from He I 10830 Angstrom Spectro-polarimetric Observation
• Velocities of an Erupting Filament
• Spectral resolution effects on the information content in solar spectra
• The He I 10830 A line: Radiative transfer and differential illumination effects
• Fast downflows in a chromospheric filament