Qorona: Open, Model-agnostic Line-of-sight Rendering of the Perpendicular Squashing Factor for Eclipse-like Coronal Imaging
6 affiliations
- 1Centre for Mathematical Plasma-Astrophysics
- 2King Abdullah University of Science and Technology 23955-6900 Thuwal
- 3Kyung Hee University
- 4Observatoire de Paris
- 5LUNEX EMMESI COSPAR-PEX Eurospacehub
- 6Maria Curie-Skłodowska University
Abstract
The fine structure of the white-light corona reflects the coronal magnetic topology, and the quasi-separatrix layers (QSLs), where the connectivity changes sharply and reconnection is expected to shape the density, are candidates for organizing it. In a coronal magnetohydrodynamic (MHD) model, the QSLs are located by the squashing factor Q , and integrating log 10 Q along the line-of-sight gives an eclipse-like image, a model-derived proxy for this structure, but no open-source tool dedicated to producing such images was previously available. To fill this gap, we present Qorona (a contraction of Q and corona; https://github.com/RayanDhib/Qorona ), an open-source Python package specifically designed to perform this rendering for any global coronal MHD solution using the perpendicular squashing factor Q ⊥ , the variant of Q that remains robust where field lines graze a boundary. Qorona is model-agnostic (a new model or file format requires only a reader) and fast: a field-line painting algorithm exploits the constancy of Q ⊥ along field lines to decouple volume resolution from tracing cost, and parallel CPU and GPU back ends build the volume in minutes. Because the volume is viewpoint-independent, a single build serves any number of cameras and a range of products beyond the eclipse image: polarity-colored and near-limb renders, a field-line view, and a synoptic signed- log 10 Q ⊥ map. The field-line tracer and Q ⊥ engine match the closed-form Q ⊥ of an analytic dipole to 10 ⁻⁹ . We demonstrate the pipeline on a COCONUT coronal MHD simulation of the 2024 April 8 total solar eclipse: the three principal streamers of the synthetic Q ⊥ image lie within 7° in position angle of those observed.
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BibTeX
@article{dhib2026qorona,
title = {{Qorona: Open, Model-agnostic Line-of-sight Rendering of the Perpendicular Squashing Factor for Eclipse-like Coronal Imaging}},
author = {Rayan Dhib and Firas Ben Ameur and Tinatin Baratashvili and Hyun-Jin Jeong and Haopeng Wang and Quentin Noraz and Brigitte Schmieder and Andrea Lani and Stefaan Poedts},
journal = {The Astrophysical Journal},
year = {2026},
month = oct,
doi = {10.3847/1538-4357/aea841},
url = {https://iopscience.iop.org/article/10.3847/1538-4357/aea841},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Qorona: Open, Model-agnostic Line-of-sight Rendering of the Perpendicular Squashing Factor for Eclipse-like Coronal Imaging
AU - Rayan Dhib
AU - Firas Ben Ameur
AU - Tinatin Baratashvili
AU - Hyun-Jin Jeong
AU - Haopeng Wang
AU - Quentin Noraz
AU - Brigitte Schmieder
AU - Andrea Lani
AU - Stefaan Poedts
PY - 2026
DA - 2026/10/14
JO - The Astrophysical Journal
DO - 10.3847/1538-4357/aea841
UR - https://iopscience.iop.org/article/10.3847/1538-4357/aea841
AB - The fine structure of the white-light corona reflects the coronal magnetic topology, and the quasi-separatrix layers (QSLs), where the connectivity changes sharply and reconnection is expected to shape the density, are candidates for organizing it. In a coronal magnetohydrodynamic (MHD) model, the QSLs are located by the squashing factor Q , and integrating log 10 Q along the line-of-sight gives an eclipse-like image, a model-derived proxy for this structure, but no open-source tool dedicated to producing such images was previously available. To fill this gap, we present Qorona (a contraction of Q and corona; https://github.com/RayanDhib/Qorona ), an open-source Python package specifically designed to perform this rendering for any global coronal MHD solution using the perpendicular squashing factor Q ⊥ , the variant of Q that remains robust where field lines graze a boundary. Qorona is model-agnostic (a new model or file format requires only a reader) and fast: a field-line painting algorithm exploits the constancy of Q ⊥ along field lines to decouple volume resolution from tracing cost, and parallel CPU and GPU back ends build the volume in minutes. Because the volume is viewpoint-independent, a single build serves any number of cameras and a range of products beyond the eclipse image: polarity-colored and near-limb renders, a field-line view, and a synoptic signed- log 10 Q ⊥ map. The field-line tracer and Q ⊥ engine match the closed-form Q ⊥ of an analytic dipole to 10 ⁻⁹ . We demonstrate the pipeline on a COCONUT coronal MHD simulation of the 2024 April 8 total solar eclipse: the three principal streamers of the synthetic Q ⊥ image lie within 7° in position angle of those observed.
SN - 0004-637X
SN - 1538-4357
ER -