Exploring Magnetic Loops and Serpentine Fields in the Quiet Sun with the GRIS-IFU

DOI: 
10.3847/1538-4357/acb33e
Publication date: 
15/02/2023
Main author: 
Campbell, Ryan J.
IAA authors: 
Gafeira, Ricardo
Authors: 
Campbell, Ryan J.;Gafeira, Ricardo;Mathioudakis, Mihalis;Noda, Carlos Quintero;Collados, Manuel
Journal: 
The Astrophysical Journal
Publication type: 
Article
Volume: 
944
Pages: 
150
Abstract: 
Synthetic observations produced from radiative magnetohydrodynamic simulations have predicted that higher polarization fractions in the quiet solar photosphere would be revealed by increasing the total integration time of observations at GREGOR resolutions. We present recently acquired disk center observations of the Fe I 15648.5 Å line obtained with the GREGOR telescope equipped with the GRIS-IFU during excellent seeing conditions, showing exceptionally high polarization fractions. Our observations reveal an internetwork region with a majority (>60%) of magnetized pixels displaying a clear transverse component of the magnetic field. This result is in stark contrast to previous disk center GRIS-IFU observations in this spectral line, which had predominantly vertical magnetic fields in the deep photosphere. At the same time, the median magnetic field strength is weaker than previous GRIS-IFU observations, indicating that the larger fraction of polarization signals cannot be explained by a more active target. We use the Stokes Inversion based on Response functions (SIR) code to analyze the data, performing over 45 million inversions, and interrogate the impact of two conflicting approaches to the treatment of noise on the retrieval of the magnetic inclination and azimuth. We present several case studies of the zoo of magnetic features present in these data, including small-scale magnetic loops that seem to be embedded in a sea of magnetism, and serpentine fields, focusing on regions where full-vector spectropolarimetry has been achieved. We also present a new open-source Python 3 analysis tool, SIR Explorer, which we use to examine the dynamics of these small-scale magnetic features.
Database: 
ADS
SCOPUS
URL: 
https://ui.adsabs.harvard.edu/#abs/2023ApJ...944..150C/abstract
ADS Bibcode: 
2023ApJ...944..150C
Keywords: 
Quiet sun;Solar photosphere;Near infrared astronomy;Solar magnetic fields;1322;1518;1093;1503;Astrophysics - Solar and Stellar Astrophysics