Horizontal Magnetic Fields Dominate the Weak Field Quiet Sun in Sunrise III Observations. Evidence from Traditional and Transformer-Based Inversions

@misc{campbell2026horizontal,
  title = {{Horizontal Magnetic Fields Dominate the Weak Field Quiet Sun in Sunrise III Observations. Evidence from Traditional and Transformer-Based Inversions}},
  author = {Ryan J. Campbell and Carlos Quintero Noda and Manuel Collados and Mihalis Mathioudakis and Andreas Lagg and Achim Gandorfer and Jose Carlos del Toro Iniesta and Yukio Katsukawa and Pietro Bernasconi and Thomas Berkefeld and Alex Feller and Tino L. Riethmüller and Alberto Álvarez-Herrero and Masahito Kubo and H. N. Smitha and David Orozco Suárez and Bianca Grauf and Michael Carpenter and Alexander Bell and Valentín Martínez Pillet and Francisco Javier Bailén and Julian Blanco Rodríguez and Juan Sebastián Castellanos Durán and Edvarda Harnes and Johannes Hölken and Francisco A. Iglesias and Ryohtaroh T. Ishikawa and Yusuke Kawabata and Takuma Matsumoto and Takayoshi Oba and Azaymi L. Siu-Tapia and Hanna Strecker and Dušan Vukadinović and Hirohisa Hara and Toshifumi Shimizu},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2608.03776},
  eprint = {2608.03776},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2608.03776},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - Horizontal Magnetic Fields Dominate the Weak Field Quiet Sun in Sunrise III Observations. Evidence from Traditional and Transformer-Based Inversions
AU  - Ryan J. Campbell
AU  - Carlos Quintero Noda
AU  - Manuel Collados
AU  - Mihalis Mathioudakis
AU  - Andreas Lagg
AU  - Achim Gandorfer
AU  - Jose Carlos del Toro Iniesta
AU  - Yukio Katsukawa
AU  - Pietro Bernasconi
AU  - Thomas Berkefeld
AU  - Alex Feller
AU  - Tino L. Riethmüller
AU  - Alberto Álvarez-Herrero
AU  - Masahito Kubo
AU  - H. N. Smitha
AU  - David Orozco Suárez
AU  - Bianca Grauf
AU  - Michael Carpenter
AU  - Alexander Bell
AU  - Valentín Martínez Pillet
AU  - Francisco Javier Bailén
AU  - Julian Blanco Rodríguez
AU  - Juan Sebastián Castellanos Durán
AU  - Edvarda Harnes
AU  - Johannes Hölken
AU  - Francisco A. Iglesias
AU  - Ryohtaroh T. Ishikawa
AU  - Yusuke Kawabata
AU  - Takuma Matsumoto
AU  - Takayoshi Oba
AU  - Azaymi L. Siu-Tapia
AU  - Hanna Strecker
AU  - Dušan Vukadinović
AU  - Hirohisa Hara
AU  - Toshifumi Shimizu
PY  - 2026
DA  - 2026/10/27
PB  - arXiv
DO  - 10.48550/arxiv.2608.03776
UR  - https://arxiv.org/abs/2608.03776
AB  - The relative prevalence of horizontal and vertical magnetic fields in the quiet-Sun remains debated, owing to the weak linear polarisation signals that make the inferred magnetic inclination distributions sensitive to observational quality and inversion methodology. We analyse observations obtained with the Sunrise Chromospheric Infrared spectroPolarimeter (SCIP). Transformer-based inversions (SINN), trained exclusively on synthetic Stokes profiles generated from a large radiative magnetohydrodynamic simulation, are compared with independent inversions performed using the \textsc{DeSIRe} code. We separate the selected pixels into weak- and strong-field populations according to their circular-polarisation amplitudes. Linear polarisation exceeding 4σ is detected in 34.6% of the field of view, enabling the magnetic topology to be constrained over a substantially larger detected population than in typical short-integration Hinode observations. Both inversion methods recover a quiet-Sun magnetic topology in which the weak fields are strongly dominated by the horizontal component, whereas strong fields exhibit a substantially more balanced topology. At logτ=−1, the median horizontal and unsigned line-of-sight field components in the weak-field population are 63 and 7~G with \textsc{DeSIRe}, and 60 and 6.5~G with SINN, respectively, corresponding to a horizontal-to-line-of-sight ratio of approximately nine for both methods. The agreement between the two fundamentally different optimisation methodologies indicates that the weak-field quiet-Sun in this dataset is characterised by a substantially stronger horizontal than vertical magnetic field component.
ER  -