Type III radio bursts associated with jets in two solar flares
4 affiliations
- 1Key Laboratory of Dark Matter and Space Science, Purple Mountain Observatory, Chinese Academy of Sciences
- 2School of Astronomy and Space Science, University of Science and Technology of China
- 3School of Computer Science, Software Engineering and Cyberspace Security, Nanjing University of Posts and Telecommunications
- 4State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences
Abstract
Context . A challenging issue is the significant velocity discrepancy between jets and energetic electrons accelerated by magnetic reconnection in solar flares.
Aims . We investigated the velocities of jets derived from extreme-ultraviolet (EUV) observations and those of energetic electrons inferred from type III radio bursts in two solar flares on 26 March 2024.
Methods . The jet velocities were measured from the time-distance maps of the Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA), while the energetic electron velocities were inferred from the type III radio burst spectra using the Aschwanden density model.
Results . These two flares are homologous events occurring in the same active region of NOAA 13615. They produce jets and type III radio bursts detected by SDO/AIA, Daocheng Radio Telescope (DART), Chashan Broadband Solar Radio Spectrometer at meter wavelengths (CBSm), and Radio and Plasma Waves (RPW). Linear fits to the jet trajectories in the plane-of-sky yield jet velocities of 436 km s ⁻¹ and 456 km s ⁻¹ for the first and second flares, respectively. The corresponding type III electron beam velocities, inferred from the Aschwanden model fitting the CBSm data, are 32.3 Mm s ⁻¹ (or 0.1 c) and 22.0 Mm s ⁻¹ (or 0.07 c), respectively. These velocities correspond to the kinetic energies of 3.0 keV and 1.4 keV, which are much lower than the cutoff energies (i.e., 18 keV) detected by the Spectrometer/Telescope for Imaging X-rays (STIX). Moreover, our DART observations show type III burst sources as funnel-like structures varying in either frequency or height in both flares. Their sizes increase rapidly with decreasing frequency, such as a ninefold expansion from 477 MHz to 164 MHz, indicating the magnetic field decreases by a factor of nine from 0.04 R ⊙ (447 MHz) to 0.10 R ⊙ (164 MHz).
Conclusions . Jets are accelerated by magnetic pressure gradients, with inferred magnetic field strengths of about 60 G at the boundaries of the reconnection regions in both events. Type III electron beams are accelerated by electric fields, with strengths of 4.3–15 ×10 ⁻⁴ V m ⁻¹ and 1.0–3.7×10 ⁻⁴ V m ⁻¹ estimated in the current sheet for the first and second flares, respectively.
Related
- Type I Solar Radio Bursts Modulated by Solar Flares
- The Association of Solar Radio Bursts with Eruptive and Confined Flares
- Kinematic Relationship Between Solar Extreme Ultraviolet Waves and Type II Metric Radio Bursts
- Source Imaging of the Multiple Type-II Solar Radio Bursts and their Multiple CME-Shock Signatures in the Corona
- Fast Radio Bursts from Monster Shocks and Flares of Inspiraling Binary Neutron Stars: A Kinetic Model for Double Pulsar
BibTeX
@article{tang2026type,
title = {{Type III radio bursts associated with jets in two solar flares}},
author = {Xiaoyu Tang and Zongjun Ning and Yuzhi Yang and Guotianci Xu and Yijie Han and Kangyi Li and Yu Huang and Jingye Yan and Li Deng and Lin Wu and Yujie Liu},
journal = {Astronomy \& Astrophysics},
year = {2026},
month = oct,
doi = {10.1051/0004-6361/202660823},
url = {https://www.aanda.org/10.1051/0004-6361/202660823},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Type III radio bursts associated with jets in two solar flares
AU - Xiaoyu Tang
AU - Zongjun Ning
AU - Yuzhi Yang
AU - Guotianci Xu
AU - Yijie Han
AU - Kangyi Li
AU - Yu Huang
AU - Jingye Yan
AU - Li Deng
AU - Lin Wu
AU - Yujie Liu
PY - 2026
DA - 2026/10/13
JO - Astronomy & Astrophysics
DO - 10.1051/0004-6361/202660823
UR - https://www.aanda.org/10.1051/0004-6361/202660823
AB - Context . A challenging issue is the significant velocity discrepancy between jets and energetic electrons accelerated by magnetic reconnection in solar flares. Aims . We investigated the velocities of jets derived from extreme-ultraviolet (EUV) observations and those of energetic electrons inferred from type III radio bursts in two solar flares on 26 March 2024. Methods . The jet velocities were measured from the time-distance maps of the Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA), while the energetic electron velocities were inferred from the type III radio burst spectra using the Aschwanden density model. Results . These two flares are homologous events occurring in the same active region of NOAA 13615. They produce jets and type III radio bursts detected by SDO/AIA, Daocheng Radio Telescope (DART), Chashan Broadband Solar Radio Spectrometer at meter wavelengths (CBSm), and Radio and Plasma Waves (RPW). Linear fits to the jet trajectories in the plane-of-sky yield jet velocities of 436 km s ⁻¹ and 456 km s ⁻¹ for the first and second flares, respectively. The corresponding type III electron beam velocities, inferred from the Aschwanden model fitting the CBSm data, are 32.3 Mm s ⁻¹ (or 0.1 c) and 22.0 Mm s ⁻¹ (or 0.07 c), respectively. These velocities correspond to the kinetic energies of 3.0 keV and 1.4 keV, which are much lower than the cutoff energies (i.e., 18 keV) detected by the Spectrometer/Telescope for Imaging X-rays (STIX). Moreover, our DART observations show type III burst sources as funnel-like structures varying in either frequency or height in both flares. Their sizes increase rapidly with decreasing frequency, such as a ninefold expansion from 477 MHz to 164 MHz, indicating the magnetic field decreases by a factor of nine from 0.04 R ⊙ (447 MHz) to 0.10 R ⊙ (164 MHz). Conclusions . Jets are accelerated by magnetic pressure gradients, with inferred magnetic field strengths of about 60 G at the boundaries of the reconnection regions in both events. Type III electron beams are accelerated by electric fields, with strengths of 4.3–15 ×10 ⁻⁴ V m ⁻¹ and 1.0–3.7×10 ⁻⁴ V m ⁻¹ estimated in the current sheet for the first and second flares, respectively.
SN - 0004-6361
SN - 1432-0746
ER -