Photospheric magnetic topology of a north polar region

¹ Leibniz-Institut für Sonnenphysik (KIS), Schöneckstr. 6, 79104 Freiburg, Germany
e-mail: apy@leibniz-kis.de
² Instituto de Astrofísica de Canarias, C. Vía Láctea s/n., 38205 La Laguna, Tenerife, Spain
³ Departamento de Astrofísica de Canarias, Universidad de La Laguna, Avda Astrofísico Sánchez s/n., 38205 La Laguna, Tenerife, Spain

Received: 10 January 2020
Accepted: 24 February 2020

Abstract

Aims. We aim to characterise the magnetism of a large fraction of the north polar region close to a maximum of activity, when the polar regions are reversing their dominant polarity.

Methods. We make use of full spectropolarimetric data from the CRisp Imaging Spectro-Polarimeter installed at the Swedish Solar Telescope. The data consist of a photospheric spectral line, which is used to infer the various physical parameters of different quiet Sun regions by means of the solution of the radiative transfer equation. We focus our analysis on the properties found for the north polar region and their comparison to the same analysis applied to data taken at disc centre and low-latitude quiet Sun regions for reference. We also analyse the spatial distribution of magnetic structures throughout the north polar region.

Results. We find that the physical properties of the polar region (line-of-sight velocity, magnetic flux, magnetic inclination and magnetic azimuth) are compatible with those found for the quiet Sun at disc centre and are similar to the ones found at low latitudes close to the limb. Specifically, the polar region magnetism presents no specific features. The structures for which the transformation from a line-of-sight to a local reference frame was possible harbour large magnetic fluxes (>10¹⁷ Mx) and are in polarity imbalance with a dominant positive polarity, the largest ones (>10¹⁹ Mx) being located below 73° latitude.