A1 Refereed original research article in a scientific journal
Source location and evolution of a multilane type II radio burst
Authors: Zucca, P; Zhang, P; Kozarev, K; Nedal, M; Dey, S; Mancini, M; Kumari, A; Morosan, DE; Dabrowski, B; Gallagher, PT; Krankowski, A; Vocks, C
Publisher: EDP SCIENCES S A
Publication year: 2025
Journal: Astronomy and Astrophysics
Article number: A271
Volume: 703
ISSN: 0004-6361
eISSN: 1432-0746
DOI: https://doi.org/10.1051/0004-6361/202554348
Publication's open availability at the time of reporting: Open Access
Publication channel's open availability : Open Access publication channel
Web address : https://doi.org/10.1051/0004-6361/202554348
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/506042237
Context. Shocks in the solar corona are capable of accelerating electrons that in turn generate radio emission known as type II radio bursts. The characteristics and morphology of these radio bursts in the dynamic spectrum reflect the evolution of the shock itself, together with the properties of the local corona where the shock propagates.
Aims. In this work we study the evolution of a complex type II radio burst with a multilane structure to find the locations where the radio emission is produced and relate them to the properties of the local environment where the shock propagates.
Methods. Using radio imaging, we were able to separately track each lane composing the type II burst and relate the position of the emission to the properties of the ambient medium, such as density, Alfv & eacute;n speed, and magnetic field.
Results. We show that the radio burst morphology in the dynamic spectrum changes with time and is related to the complexity of the local environment. The initial stage of the radio emission is characterized by a single broad lane in the spectrum, while the later stages of the radio signature evolve in a multilane scenario. The radio imaging reveals how the initial stage of the radio emission separates with time into different locations along the shock front as the density and orientation of the magnetic field change along the shock propagation. At the time when the spectrum shows a multilane shape, we find a clear separation of the imaged radio sources propagating in regions with different densities.
Conclusions. By combining radio imaging with the properties of the local corona, we describe the evolution of a type II radio burst and, for the first time, identify three distinct radio emission regions above the coronal mass ejection front. Two regions were located at the flanks, producing earlier radio emission than the central position, in accordance with the complexity of density and Alfv & eacute;n speed values in the regions where radio emission is generated. This unprecedented observation of a triple-source structure provides new insights into the nature of multilane type II bursts.
Downloadable publication This is an electronic reprint of the original article. |  |
Funding information in the publication:
This paper is based on data obtained with the International LOFAR Telescope (ILT) under project code LT16-001 with PI Dr. P. Zucca. LOFAR (van Haarlem et al. 2013) is the Low Frequency Array designed and constructed by ASTRON. It has observing, data processing, and data storage facilities in several countries, that are owned by various parties (each with their own funding sources), and that are collectively operated by the ILT foundation under a joint scientific policy. The ILT resources have benefited from the following recent major funding sources: CNRS-INSU, Observatoire de Paris and Université d’Orléans, France; BMBF, MIWF-NRW, MPG, Germany; Science Foundation Ireland (SFI), Department of Business, Enterprise and Innovation (DBEI), Ireland; NWO, The Netherlands; The Science and Technology Facilities Council, UK; Polish Ministry of Science and Higher Education number: 2021/WK/2. KK acknowledges support by the Bulgarian National Science Fund, VIHREN program, under contract KP-06-DV-8/18.12.2019 (MOSAIICS project), as well as support from the LOFAR-BG project of the National Roadmap for Research Infrastructure of Bulgaria under contract D 01-110/30.06.2025. AK acknowledges the ANRF Prime Minister Early Career Research Grant (PM ECRG) program. D.E.M. acknowledges the Research Council of Finland project ‘SolShocks’ (grant number 354409). MN acknowledges support by the project “The Origin and Evolution of Solar Energetic Particles”, funded by the European Office of Aerospace Research and Development under award No. FA8655-24-1-7392. P.Z. acknowledges support for this research by the NASA Living with a Star Jack Eddy Postdoctoral Fellowship Program, administered by UCAR’s Cooperative Programs for the Advancement of Earth System Science (CPAESS) under award 80NSSC22M0097. S.D. acknowledges support from the Department of Atomic Energy, under project 12-R&D-TFR-5.02-0700. SDO data are courtesy of NASA/SDO and the AIA science teams. SUVI data are courtesy of NOAA/NESDIS/NCEI. The authors thank the Predictive Science team (https://www.predsci.com/) for making their MHD simulation results available. The authors would like to thank the radio observatory of Nançay for making the NRH and ORFEES data available. This research used the SunPy open source software package (The SunPy Community 2020). We thank the project LOFAR Data Valorization (LDV) [project numbers 2020.031, 2022.033, and 2024.047] of the research programme Computing Time on National Computer Facilities using SPIDER that is (co-)funded by the Dutch Research Council (NWO), hosted by SURF through the call for proposals of Computing Time on National Computer Facilities. We also thank SURF SARA with the project EINF-13633, Science ready products for LOFAR Solar, Heliospheric and ionospheric datasets.
