The relation between magnetic field inclination and the apparent motion of penumbral grains

0584409 - ASÚ 2025 FR eng J - Journal Article
Sobotka, Michal - Jurčák, Jan - Duran, J. S. C. - García-Rivas, Marta
The relation between magnetic field inclination and the apparent motion of penumbral grains.
Astronomy & Astrophysics. Roč. 682, February (2024), č. článku A65. ISSN 0004-6361. E-ISSN 1432-0746
R&D Projects: GA ČR(CZ) GF23-07633K
EU Projects: European Commission(XE) 824135 - SOLARNET
Institutional support: RVO:67985815
Keywords : solar optical telescope * magnetic fields * photosphere
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 6.5, year: 2022
Method of publishing: Open access

We aim to ascertain statistically whether the direction of PGs' apparent motion is related to the inclination of the surrounding magnetic field. We used spectropolarimetric observations of five sunspot penumbrae to compare magnetic inclinations inside PGs with those in their surroundings. The data were taken by three observatories: the Hinode satellite, the Swedish Solar Telescope, and the GREGOR solar telescope. The direction of PGs' motion was determined by feature tracking. The atmospheric conditions in PGs and their surroundings, including magnetic field information, were retrieved by means of height-stratified spectropolarimetric inversions. Out of a sample of 444 inward-moving PGs and 269 outward-moving ones, we show that 43% of the inward-moving PGs have a magnetic inclination larger by 8 degrees +/- 4 degrees than the inclination in their surroundings and 51% of the outward-moving PGs have an inclination smaller by 13 degrees +/- 7 degrees than the surrounding one. The opposite relation of inclinations is observed in only one fifth of the inward- and outward-moving PGs. Rising hot plasma in PGs surrounded by a less inclined magnetic field may adapt its trajectory to be more vertical, causing an inward apparent motion of PGs. Conversely, it may be dragged by a more horizontal surrounding magnetic field such that an outward apparent motion is observed.
Permanent Link: https://hdl.handle.net/11104/0353681