Work

Study of an active region prominence using spectropolarimetric data in the He I D3 multiplet

Year: 2025

Type: article

Abstract: Context. Prominences are cool overdensities of plasma supported by magnetic fields that levitate in the solar corona. The physical characterization of these structures is key for understanding the magnetic field in the corona. Aims. Our work attempts to shed light on the properties of prominences by using observations at high polarimetric sensitivity in the He I D3 multiplet taken with the Zürich Imaging Polarimeter-3 instrument at the Istituto ricerche solari Aldo e Cele Daccò. Methods. We used the Hanle and Zeeman light inversion code to infer the thermodynamic and magnetic properties of an active region prominence, assuming one- and two-component models. Results. Our observations unveil a great diversity of physical conditions in the prominence. The observed Stokes profiles are usually broad and show interesting features, which can be described assuming a two-component model. The contribution of each component and the trends inferred for some parameters vary with the distance to the solar limb. While both components have analogous properties and contribute similarly close to the limb, a major component mainly describes the properties inferred at 10–40″ away from the limb. Moreover, both components usually show significant differences in thermal broadening, which is essential for ensuring a good fit quality between observations and synthetic profiles. Summarizing, the observed region of the prominence shows line-of-sight velocities of 1–3 km s−1 and rather horizontal fields of 20–80 gauss. We also report hints of a twist close to a prominence foot and changes in the magnetic configuration at specific locations. Conclusions. Our results indicate a mainly horizontal magnetic field of a few tens of gauss in the prominence. A model of two components with different thermal broadenings and filling factors, depending on the limb distance, is crucial for providing a consistent solution across most of the observed prominence.

Source: Astronomy and Astrophysics

DOI: 10.1051/0004-6361/202452439

Authors: S. Esteban Pozuelo, A. Asensio Ramos, J. Trujillo Bueno, R. Ramelli, F. Zeuner, M. Bianda

Institutions: Universidad de La Laguna, Instituto de Astrofísica de Canarias, Istituto Ricerche Solari Locarno, Università della Svizzera italiana

Language: English

Topic: Solar and Space Plasma Dynamics

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,865