Exploring magnetic field properties at the boundary of solar pores: A comparative study based on SDO-HMI observations^⋆

¹ IGAM, Institute of Physics, University of Graz, Universitätsplatz 5, 8010 Graz, Austria
e-mail: jose.campos-rozo@uni-graz.at
² Universidad Nacional de Colombia, Observatorio Astronómico Nacional, Teusaquillo, Bogotá, Colombia
³ Neuroimaging Science and Support Center-NISSC, Institute of Neurology, Kepler University Hospital, Wagner-Jauregg-Weg 15, 4020 Linz, Austria

Received: 12 March 2023
Accepted: 19 April 2023

Abstract

Context. The Sun’s magnetic fields play an important role in various solar phenomena. Solar pores are regions of intensified magnetic field strength compared to the surrounding photospheric environment, and their study can help us better understand the properties and behaviour of magnetic fields in the Sun. In this work, we investigate the properties of magnetic fields on the boundaries of solar pores, specifically focusing on the evolution of the vertical magnetic field.

Aims. Up to now, there exists only a single study on magnetic field properties at the boundary region of a pore. Therefore, the main goal of this work is to increase the statistics of magnetic properties determining the pore boundary region. To this aim, we study the change of the vertical magnetic field on the boundaries of six solar pores and their time evolution.

Methods. We analyse six solar pores using data from the Helioseismic and Magnetic Imager instrument on board the Solar Dynamics Observatory. We apply image processing techniques to extract the relevant features of the solar pores and determine the boundary conditions of the magnetic fields. For each pore, the maximal vertical magnetic field is determined, and the obtained results are compared with the above-mentioned previous study.

Results. We find the maximal vertical magnetic field values on the boundaries of the studied solar pores to range from 1400 G to 1600 G, with a standard deviation between 7.8% and 14.8%. These values are lower than those reported in the mentioned preceding study. However, this can be explained by differences in spatial resolution as well as the type of data we used. For all the pores, we find that the magnetic inclination angle lies in a range of 30 ± 7°, which is consistent with the idea that the magnetic field configuration in solar pores is mainly vertical.

Conclusions. The vertical magnetic field is an important factor in determining the boundary of solar pores, and it plays a more relevant role than the intensity gradient. The obtained information will be useful for future studies on the formation and evolution of magnetic structures of the Sun. Additionally, this study highlights the importance of high spatial resolution data for the purpose of accurately characterising the magnetic properties of solar pores. Overall, the findings of this work contribute to the understanding of the magnetic field properties of the Sun and will be crucial for improving models of solar dynamics and magnetic flux emergence.