Issue |
A&A
Volume 696, April 2025
|
|
---|---|---|
Article Number | A187 | |
Number of page(s) | 11 | |
Section | The Sun and the Heliosphere | |
DOI | https://doi.org/10.1051/0004-6361/202553752 | |
Published online | 18 April 2025 |
Dynamic spectra of solar radio emissions from weak-turbulence simulation
1
Centre for Mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, Celestijnenlaan 200B, B-3001 Leuven, Belgium
2
Institute for Theoretical Physics IV, Faculty for Physics and Astronomy, Ruhr University Bochum, D-44780 Bochum, Germany
3
Instituto de Física, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre, RS, Brazil
4
Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742-2431, USA
5
Research Center in the intersection of Plasma Physics, Matter, and Complexity ( P 2 mc), Comisión Chilena de Energía Nuclear, Casilla 188-D, Santiago, Chile
6
Departamento de Ciencias Físicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Sazié 2212, Santiago 8370136, Chile
7
Institute of Physics, University of Maria Curie-Sklodowska, ul. Radziszewskiego 10, 20-031 Lublin, Poland
⋆ Corresponding author; marian.lazar@kuleuven.be
Received:
14
January
2025
Accepted:
8
March
2025
Context. In recent decades, serious efforts have been made in the analytical and numerical modeling of solar radio bursts generated by the electron beam interacting with the background plasma, including the dynamic spectra with decreasing frequency over time/space. These are type II and type III radio bursts, with the fundamental components at the local plasma frequency (ωp = 2πfp) and the harmonics (nωp = 2πnfp). Synthetic spectra built for a number of radio events were able to reproduce the decreasing frequency profiles reasonably well, despite the limitations of the approximate analytical theory.
Aims. We propose new modeling of dynamic radio emission spectra using weak-turbulence (WT) theory. This novel approach also aims at a self-consistent and quantitative evaluation of radio emissions, based on first-principles modeling of electron beam plasma instabilities and nonlinear wave interaction.
Methods. We performed the WT simulation, which has the ability to quantitatively describe the standard plasma emission involving the nonlinear interaction of Langmuir (L), ion-sound (S), and transverse electromagnetic (T) waves. The composite dynamic spectra are constructed for type II- and type III-like events, against the background electron density model that behaves as an inverse square of the distance from the solar source.
Results. The new dynamic spectra are obtained distinctly, with a rapid frequency shift for type III emissions (generated by fast electron beams from coronal sources), as well as a less steep frequency drop for type II spectra (whose sources move away from the Sun along with interplanetary shocks). Upon making a qualitative comparison with typical solar radio emission events, we find that our first-principle-based synthetic dynamic spectra are in good agreement.
Conclusions. The findings of the present study demonstrate that the theoretical approach taken in this paper can be further applied to obtain (i) quantitatively relevant predictions and replications of the observed dynamic spectra of radio bursts, and (ii) more realistic large-scale models of the solar radio source, for example the type II and type III source models computed from the large-scale magnetohydrodynamics (MHD) simulations or even from direct spacecraft observations.
Key words: Sun: corona / Sun: coronal mass ejections (CMEs) / Sun: flares / Sun: radio radiation
© The Authors 2025
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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