Spectropolarimetry of solar prominences

TL;DR

This study presents high-precision spectropolarimetric observations of solar prominences across multiple spectral lines, revealing magnetic field signatures via Zeeman and Hanle effects, and employing inversion techniques for magnetic field diagnostics.

Contribution

It provides detailed spectropolarimetric data of prominences with minimized observational artifacts and applies advanced inversion methods to infer magnetic field vectors.

Findings

Detection of anti-symmetric V profiles in Halpha indicating Zeeman effect signatures.

Successful control and correction of instrumental polarization effects.

Application of Stokes inversion to deduce magnetic field properties in prominences.

Abstract

A large set of high precision full-Stokes spectropolarimetric observations of prominences in He-D3, Halpha and Hbeta lines has been recorded with the ZIMPOL polarimeter at the Gregory-Coude Telescope in Locarno. The observational technique allows us to obtain measurements free from seeing induced spurious effects. The instrumental polarization is well under control and taken into account in the data analysis. We present our observational results for each of the above-mentioned lines. Of particular interest is that most of our Halpha measurements show anti-symmetric V profiles that are a characteristic signature of the Zeeman effect in the prominence plasma. A Stokes inversion technique based on the quantum theory of the Hanle and Zeeman effects is being applied on observed Stokes profiles in the He-D3 line in order to obtain information on the magnetic field vector that confines the prominence plasma.