Multicomponent He I 10830 {\AA} profiles in an active filament

TL;DR

This study presents spectropolarimetric observations of an active solar filament's chromosphere, revealing complex He I 10830 Å profiles with multiple atmospheric components and high-velocity flows, and demonstrates reliable inversion techniques.

Contribution

It introduces a method to invert complex He I 10830 Å profiles with multiple atmospheric components and high velocities in an active filament.

Findings

Detection of up to five atmospheric components in a single profile.

Observation of supersonic velocities up to 100 km/s.

Successful inversion of complex spectral profiles.

Abstract

We present new spectropolarimetric observations of the chromospheric He I 10830 {\AA} multiplet observed in a filament during its phase of activity. The data were recorded with the new Tenerife Infrared Polarimeter (TIP-II) at the German Vacuum Tower Telescope (VTT) on 2005 May 18. We inverted the He Stokes profiles using multiple atmospheric components. The observed He Stokes profiles display a remarkably wide variety of shapes. Most of the profiles show very broad Stokes I absorptions and complex and spatially variable Stokes V signatures. The inversion of the profiles shows evidence of different atmospheric blue- and redshifted components of the He I lines within the resolution element (1 arcsec), with supersonic velocities of up to 100 km/s. Up to five different atmospheric components are found in the same profile. We show that even these complex profiles can be reliably inverted.