Journal Article

The First out-of-Ecliptic Observations of the Polar Magnetic Field of the Sun

Orozco Suárez, D, Blanco Rodríguez, J, Volkmer, R, Strecker, H, Albert, K, Korpi-Lagg, A, Woch, J, Calchetti, D, Solanki, S. K, Giunta, A, Gandorfer, A, Bellot Rubio, L. R, Schühle, U, Grundy, T, Ulyanov, A, Bailén, F. J, Chitta, L. P, Hirzberger, J, Schou, J, Moreno Vacas, A, Oba, T, Sinjan, J, del Toro Iniesta, J. C, Appourchaux, T, Li, X, Feller, A, Gizon, L, Valori, G

2025

Overview

Direct remote-sensing observations of the solar poles have been hindered by the restricted view obtained from the ecliptic plane. For the first time ever, Solar Orbiter with its remote-sensing instruments observed the poles of the Sun from out of the ecliptic in the spring of 2025. Here, we report the first measurements of the magnetic field of the solar poles taken when Solar Orbiter was at heliographic latitudes ranging between 14 .° 9 and 16 .° 7. The data sets were collected by the High Resolution Telescope of the Polarimetric and Helioseismic Imager on board Solar Orbiter (SO/PHI-HRT). Two sets of observations, approximately one month apart, for the south and north pole are considered in this work. The magnetic flux and flux density measured during these campaigns are reported as a function of the heliographic latitude observed by SO/PHI-HRT. The net fluxes show a different latitudinal distribution for the two polar caps. We also discuss the observed dependence of the measured fluxes on the viewing angle. These first results highlight the importance of high-resolution direct measurements of the polar field, paving the way for the high-latitude observations planned for SO/PHI-HRT in the coming years.

• Publisher: IOP Publishing
• Subject: Ecliptic / Flux density / High resolution / Latitude / Magnetic fields / Magnetic flux / North Pole / Polar caps / Remote sensing / Solar magnetic field / Solar orbits