Imaging-spectroscopy of a band-split type II solar radio burst with the Murchison Widefield Array

Bhunia, Shilpi; Carley, Eoin; Oberoi, D.; Gallagher, P. T.

doi:10.1051/0004-6361/202244456

Cited by 9 publications

(6 citation statements)

References 72 publications

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“…Though the early classification has stood the test of time for some seventy years, every significant advancement in instrumentation capabilities has brought about discoveries of previously unappreciated aspects of emissions at finer scales, often leading to elaborate sub-classification of each burst type. The most recent wave of such discoveries is in progress today, owing to instruments like the MWA and LOFAR (e.g., Suresh et al 2017;Kontar et al 2017;Sharykin et al 2018;Mohan et al 2019a, b;Magdalenić et al 2020;Mohan 2021a;Mondal & Oberoi 2021;Bhunia et al 2023). Of the various solar burst types, we focus on the ones which had garnered a lot of attention in the recent past primarily owing to some notable discoveries.…”

Section: Studies Of Solar Radio Burstsmentioning

confidence: 99%

Preparing for solar and heliospheric science with the SKAO: An Indian perspective

et al. 2023

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The Square Kilometre Array Observatory (SKAO) is perhaps the most ambitious radio telescope envisaged yet. It will enable unprecedented studies of the Sun, corona and heliosphere and help to answer many of the outstanding questions in these areas. Its ability to make a vast previously unexplored phase space accessible, also promises a large discovery potential. The Indian solar and heliospheric physics community has been preparing for this science opportunity. A significant part of this effort has been towards playing a leading role in pursuing science with SKAO precursor instruments. This paper briefly summarises the current status of the various aspects of work done as a part of this enterprise and our future goals.

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Section: Studies Of Solar Radio Burstsmentioning

confidence: 99%

Preparing for solar and heliospheric science with the SKAO: An Indian perspective

et al. 2023

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“…Imaging spectroscopy of type II radio bursts can be used to locate shock-accelerated electron beams (e.g., Zucca et al 2018;Morosan et al 2019). With the new availability of low-frequency radio imaging, recent studies have provided improved multifrequency images of type II bursts and associated fine structures (e.g., Zucca et al 2018;Morosan et al 2019;Chrysaphi et al 2020;Bhunia et al 2023). For example, Zucca et al (2018) used the tied-array beam observation mode (Morosan et al 2014) of the Low Frequency Array (LOFAR; van Haarlem et al 2013) on a type II solar radio burst.…”

Section: Introductionmentioning

confidence: 99%

“…Morosan et al (2019) also used tiedarray beam imaging observations from LOFAR to image herringbone bursts and identified the presence of shock-accelerated They find that the radio source is located about 0.5 solar radii above a solar jet, which suggests the type II burst was generated by a jet-driven piston shock, instead of a CME-driven shock wave. In another study with the Murchison Widefield Array (MWA), Bhunia et al (2023) performed radio imaging of a band-splitting type II event at multiple frequencies and found that the radio source is located at multiple locations close to the shock. Spatially resolved radiometry analysis is a powerful tool for analyzing the electron beam locations and propagation in detail, by imaging the fine structures in dynamic spectra.…”

Section: Introductionmentioning

confidence: 99%

Spatially resolved radio signatures of electron beams in a coronal shock

Zhang,

Morosan,

Kumari

et al. 2024

A&A

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Type II radio bursts are a type of solar radio bursts associated with coronal shocks. Type II bursts usually exhibit fine structures in dynamic spectra that represent signatures of accelerated electron beams. So far, the sources of individual fine structures in type II bursts have not been spatially resolved in high-resolution low-frequency radio imaging. The objective of this study is to resolve the radio sources of the herringbone bursts found in type II solar radio bursts and investigate the properties of the acceleration regions in coronal shocks. We used low-frequency interferometric imaging observations from the Low Frequency Array to provide a spatially resolved analysis for three herringbone groups (A, B, and C) in a type II radio burst that occurred on 16 October 2015. The herringbones in groups A and C have a typical frequency drift direction and a propagation direction along the frequency. Their frequency drift rates correspond to those of type III bursts and previously studied herringbones. Group B has a more complex spatial distribution, with two distinct sources separated by 50 arcsec and no clear spatial propagation with frequency. One of the herringbones in group B was found to have an exceptionally large frequency drift rate. The characteristics derived from imaging spectroscopy suggest that the studied herringbones originate from different processes. Herringbone groups A and C most likely originate from single-direction beam electrons, while group B may be explained by counterstreaming beam electrons.

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“…Type II bursts are associated with expanding CME-driven shock waves (e.g., Zimovets et al 2012;Zucca et al 2014Zucca et al , 2018Mancuso et al 2019; Morosan et al 2020a) and in rare cases with the expansion of a coronal shock wave in the absence of a CME (e.g., Magdalenić et al 2012;Su et al 2015;Maguire et al 2021;Morosan et al 2023). Type II bursts often show splitbands of emission that are believed to originate from different regions of the shock front (e.g., Holman & Pesses 1983;Bhunia et al 2023) or from the upstream and downstream regions of the shock (e.g., Smerd et al 1975;Kumari et al 2017). Herringbone bursts usually stem from a type II lane or "backbone", however, they are sometimes observed without an accompanying type II burst (Holman & Pesses 1983;Cane & White 1989;Mann & Klassen 2005;Morosan et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Connecting remote and in situ observations of shock-accelerated electrons associated with a coronal mass ejection

Morosan,

Pomoell,

Palmroos

et al. 2024

A&A

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One of the most prominent sources for energetic particles in our Solar System are huge eruptions of magnetised plasma from the Sun, known as coronal mass ejections (CMEs), which usually drive shocks that accelerate charged particles up to relativistic energies. In particular, energetic electron beams can generate radio bursts through the plasma emission mechanism, for example, type II and accompanying herringbone bursts. In this work, we investigate the acceleration location, escape, and propagation directions of various electron beams in the solar corona and compare them to the arrival of electrons at spacecraft. To track energetic electron beams, we used a synthesis of remote and direct observations combined with coronal modeling. Remote observations include ground-based radio observations from the Nan c ay Radioheliograph (NRH) combined with space-based extreme-ultraviolet and white-light observations from Solar Dynamics Observatory (SDO), Solar Terrestrial Relations Observatory (STEREO), and Solar Orbiter (SolO). We also used direct observations of energetic electrons from the STEREO and Wind spacecraft. These observations were then combined with a three-dimensional (3D) representation of the electron acceleration locations, including the results of magneto-hydrodynamic (MHD) models of the solar corona. This representation was subsequently used to investigate the origin of electrons observed remotely at the Sun and their link to in situ electrons. We observed a type II radio burst followed by herringbone bursts that show single-frequency movement through time in NRH images. The movement of the type II burst and herringbone radio sources seems to be influenced by regions in the corona where the CME is more capable of driving a shock. We found two clear distinct regions where electrons are accelerated in the low corona and we found spectral differences between the radio emission generated in these regions. We also found similar inferred injection times of near-relativistic electrons at spacecraft to the emission time of the type II and herringbone bursts. However, only the herringbone bursts propagate in a direction where the shock encounters open magnetic field lines that are likely to be magnetically connected to the same spacecraft. Our results indicate that if the in situ electrons are indeed shock-accelerated, the most likely origin of the in situ electrons arriving first is located near the acceleration site of herringbone electrons. This is the only region during the early evolution of the shock where there is clear evidence of electron acceleration and an intersection of the shock with open field lines, which can be directly connected to the observing spacecraft.

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Imaging-spectroscopy of a band-split type II solar radio burst with the Murchison Widefield Array

Cited by 9 publications

References 72 publications

Preparing for solar and heliospheric science with the SKAO: An Indian perspective

Preparing for solar and heliospheric science with the SKAO: An Indian perspective

Spatially resolved radio signatures of electron beams in a coronal shock

Connecting remote and in situ observations of shock-accelerated electrons associated with a coronal mass ejection

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