Cause of chromospheric opposite polarity intrusions discovered in Sunrise III/SCIP data: MURaM-ChE simulations point to twisted flux ropes

@misc{ondratschek2026cause,
  title = {{Cause of chromospheric opposite polarity intrusions discovered in Sunrise III/SCIP data: MURaM-ChE simulations point to twisted flux ropes}},
  author = {Patrick A. Ondratschek and Damien F. Przybylski and Robert H. Cameron and H. N. Smitha and Sami K. Solanki and Masahito Kubo 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. Riethmueller and Alberto Alvarez-Herrero and David Orozco Suarez and Bianca Grauf and Michael Carpenter and Alexander Bell and Valentin Martinez Pillet and Laurent Gizon and Francisco Javier Bailen and Julian Blanco Rodriguez and Juan Sebastian Castellanos Duran and Edvarda Harnes and Johannes Hoelken 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 Dusan Vukadinovic and Hirohisa Hara and Toshifumi Shimizu},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.20933},
  eprint = {2609.20933},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.20933},
  note = {CC BY-SA 4.0},
}

TY  - UNPB
TI  - Cause of chromospheric opposite polarity intrusions discovered in Sunrise III/SCIP data: MURaM-ChE simulations point to twisted flux ropes
AU  - Patrick A. Ondratschek
AU  - Damien F. Przybylski
AU  - Robert H. Cameron
AU  - H. N. Smitha
AU  - Sami K. Solanki
AU  - Masahito Kubo
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. Riethmueller
AU  - Alberto Alvarez-Herrero
AU  - David Orozco Suarez
AU  - Bianca Grauf
AU  - Michael Carpenter
AU  - Alexander Bell
AU  - Valentin Martinez Pillet
AU  - Laurent Gizon
AU  - Francisco Javier Bailen
AU  - Julian Blanco Rodriguez
AU  - Juan Sebastian Castellanos Duran
AU  - Edvarda Harnes
AU  - Johannes Hoelken
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  - Dusan Vukadinovic
AU  - Hirohisa Hara
AU  - Toshifumi Shimizu
PY  - 2026
DA  - 2026/09/17
PB  - arXiv
DO  - 10.48550/arxiv.2609.20933
UR  - https://arxiv.org/abs/2609.20933
AB  - The Sunrise Chromospheric Infrared spectroPolarimeter (SCIP) instrument onboard the balloon-borne Sunrise III observatory provided new high-resolution observations of the solar chromosphere in the Ca II 854.2 nm line. The Stokes-V signal in magnetic network regions was found to show fine-structured details, which suggests the magnetic field above the network elements does not simply expand as a unipolar feature but displays opposite-polarity-intrusions (OPIs). These features appear as elongated structures in Stokes-V observations. In this work, we demonstrate that such features appear ubiquitously in a numerical simulation of the solar chromosphere. We use a simulation that is computed with the recently developed chromospheric extension of MURaM (MURaM-ChE) and resembles an enhanced network region. We find that OPIs appear ubiquitously in the vertical component of the magnetic field at around 1 Mm above the surface and are visible in the synthetic Stokes-V signal of the Ca II 854.2 nm line. The structures have lengths of 2 Mm to 7 Mm and widths of approximately 1 Mm. The magnetic field configurations associated with the OPI features appear to belong to twisted flux ropes (TFRs) and are visible for most of the time in the presented 21 min time series. Our results show that the magnetic structure of the chromosphere is more complex than previously thought, with even seemingly simple flux tubes showing embedded twisted fields pointing in the opposite direction. This may help in explaining new high-resolution observations from the Sunrise III mission.
ER  -