<p>Coronal arcade loops play a key role in our understanding of solar activity because they contain plasma within closed magnetic field lines. Although these structures have been extensively studied using various observational techniques, combining radio and extreme ultraviolet (EUV) observations provides a unique opportunity to analyse their properties more comprehensively. In this study, we present the first three-dimensional characterisation of coronal loops by analysing simultaneous observations of type J solar radio bursts and EUV imaging. Data were collected from the Observations Radiospectrographiques pour FEDOME et l’Étude des Éruptions Solaires, the Nançay Radioheliograph, and the Solar Dynamics Observatory/Atmospheric Imaging Assembly instruments during an event on 6 March 2014. Our results reveal a direct spatial correlation between the sources of type J bursts and visible coronal loops. Using a new methodology combining radio polarisation measurements and EUV-based three-dimensional loop reconstruction, we determined several key physical parameters: a temperature of approximately 0.82 MK, an electron density distribution ranging from around <InlineEquation ID="IEq1"> <EquationSource Format="MATHML"><math> <msup> <mrow> <mn>10</mn> </mrow> <mrow> <mn>9</mn> </mrow> </msup> <msup> <mtext> cm</mtext> <mrow> <mo>−</mo> <mn>3</mn> </mrow> </msup> </math></EquationSource> <EquationSource Format="TEX">$10^{9}\text{ cm}^{-3}$</EquationSource> </InlineEquation> at the foot of the loop to around <InlineEquation ID="IEq2"> <EquationSource Format="MATHML"><math> <msup> <mrow> <mn>10</mn> </mrow> <mrow> <mn>7</mn> </mrow> </msup> <msup> <mtext> cm</mtext> <mrow> <mo>−</mo> <mn>3</mn> </mrow> </msup> </math></EquationSource> <EquationSource Format="TEX">$10^{7}\text{ cm}^{-3}$</EquationSource> </InlineEquation> at the top, and a magnetic field strength varying from around 850 Gauss at the footpoint to around 5 Gauss at the top. Our results confirm the validity of hydrostatic equilibrium and dipole field models for coronal loops while providing unprecedented insights into their three-dimensional structure and physical properties. This research introduces a new diagnostic technique for studying coronal loop dynamics and their role in solar eruptions.</p>

Three-Dimensional Characterization of Coronal Loops Using Combined Radio and EUV Observations

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发表日期：

2025年12月5日

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Shiwei Feng,
Xinhua Zhao,
Pietro Zucca,
Y. Zhou,
D. N. Liu,
X. Qin

摘要

Coronal arcade loops play a key role in our understanding of solar activity because they contain plasma within closed magnetic field lines. Although these structures have been extensively studied using various observational techniques, combining radio and extreme ultraviolet (EUV) observations provides a unique opportunity to analyse their properties more comprehensively. In this study, we present the first three-dimensional characterisation of coronal loops by analysing simultaneous observations of type J solar radio bursts and EUV imaging. Data were collected from the Observations Radiospectrographiques pour FEDOME et l’Étude des Éruptions Solaires, the Nançay Radioheliograph, and the Solar Dynamics Observatory/Atmospheric Imaging Assembly instruments during an event on 6 March 2014. Our results reveal a direct spatial correlation between the sources of type J bursts and visible coronal loops. Using a new methodology combining radio polarisation measurements and EUV-based three-dimensional loop reconstruction, we determined several key physical parameters: a temperature of approximately 0.82 MK, an electron density distribution ranging from around $10^{9} {cm}^{- 3}$ $10^{9}\text{ cm}^{-3}$ at the foot of the loop to around $10^{7} {cm}^{- 3}$ $10^{7}\text{ cm}^{-3}$ at the top, and a magnetic field strength varying from around 850 Gauss at the footpoint to around 5 Gauss at the top. Our results confirm the validity of hydrostatic equilibrium and dipole field models for coronal loops while providing unprecedented insights into their three-dimensional structure and physical properties. This research introduces a new diagnostic technique for studying coronal loop dynamics and their role in solar eruptions.