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Radio emission observations from the Learmonth and Bruny Island radio spectrographs are analysed to determine the nature of a train of discrete, periodic radio \lq sparks\rq (finite-bandwidth, short-duration isolated radio features) which…

Solar and Stellar Astrophysics · Physics 2016-10-19 C. R. Goddard , G. Nisticò , V. M. Nakariakov , I. V. Zimovets , S. M. White

Radio observations discovered large scale non thermal sources in the central Mpc regions of dynamically disturbed galaxy clusters (radio halos). The morphological and spectral properties of these sources suggest that the emitting electrons…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-05 G. Brunetti , R. Cassano

In this paper, we present for the first time a comprehensive statistical study between type II radio bursts from the metric (m) to the dekameric-hectometric (DH) domain and their associated solar and space weather (SW) phenomena, namely,…

Solar and Stellar Astrophysics · Physics 2025-07-03 Pooja Devi , Rositsa Miteva , Ramesh Chandra , Kostadinka Koleva , Bendict Lawrance

Type III radio bursts are intense radio emissions triggered by beams of energetic electrons often associated with solar flares. These exciter beams propagate outwards from the Sun along an open magnetic field line in the corona and in the…

Solar and Stellar Astrophysics · Physics 2015-08-19 Vratislav Krupar , Eduard P. Kontar , Jan Soucek , Ondrej Santolik , Milan Maksimovic , Oksana Kruparova

Solar coronal shocks are very common phenomena in the solar atmosphere and are believed to be the drivers of solar type II radio bursts. However, the microphysical nature of these emissions is still an open problem. This paper proposes that…

Solar and Stellar Astrophysics · Physics 2015-06-19 G. Q. Zhao , L. Chen , D. J. Wu

Drift pairs are an unusual type of fine structure sometimes observed in dynamic spectra of solar radio emission. They appear as two identical short narrowband drifting stripes separated in time; both positive and negative frequency drifts…

Solar and Stellar Astrophysics · Physics 2019-10-23 Alexey Kuznetsov , Eduard Kontar

This paper presents multiwavelength observations of a flare-generated type II radio burst. The kinematics of the shock derived from the type II closely match a fast EUV wave seen propagating through coronal arcade loops. The EUV wave was…

Solar and Stellar Astrophysics · Physics 2016-08-31 Pankaj Kumar , D. E. Innes , K. S. Cho

Context: Solar eruptions, such as coronal mass ejections (CMEs), are often accompanied by accelerated electrons that can in turn emit radiation at radio wavelengths. This radiation is observed as solar radio bursts. The main types of bursts…

Solar and Stellar Astrophysics · Physics 2021-03-31 D. E. Morosan , A. Kumari , E. K. J. Kilpua , A. Hamini

Aims. We examine high time resolution dynamic spectra for fine structures in type II solar radio bursts Methods. We used data obtained with the (SAO) receiver of the Artemis-JLS (ARTEMIS-IV) solar radio spectrograph in the 450-270 MHz range…

Solar and Stellar Astrophysics · Physics 2019-04-17 S. Armatas , C. Bouratzis , A. Hillaris , C. E. Alissandrakis , P. Preka-Papadema , X. Moussas , E. Mitsakou , P. Tsitsipis , A. Kontogeorgos

Electron beams accelerated in solar flares and escaping from the Sun along open magnetic field lines can trigger intense radio emissions known as type III solar radio bursts. Utilizing observations by Parker Solar Probe (PSP), STEREO-A…

Solar and Stellar Astrophysics · Physics 2025-10-02 Francesco Azzollini , Eduard P. Kontar

Extended radio sources in the sky require a dense sampling of short baselines to be properly imaged by interferometers. This problem arises in many areas of radio astronomy, such as in the study of galaxy clusters, which may host Mpc-scale…

Recent developments in astronomical radio telescopes opened new opportunities in imaging and spectroscopy of solar radio bursts at sub-second timescales. Imaging in narrow frequency bands has revealed temporal variations in the positions…

Solar and Stellar Astrophysics · Physics 2020-12-16 Xingyao Chen , Eduard P. Kontar , Nicolina Chrysaphi , Natasha L. S. Jeffrey , Mykola Gordovskyy , Yihua Yan , Baolin Tan

In recent studies (Feng et al., 2012; Kong et al., 2012), we proposed that source properties of type II radio bursts can be inferred through a causal relationship between the special shape of the type II dynamic spectrum (e.g., bump or…

Solar and Stellar Astrophysics · Physics 2015-06-15 S. W. Feng , Y. Chen , X. L. Kong , G. Li , H. Q. Song , X. S. Feng , F. Guo

Type II radio bursts are often associated with coronal shocks that are typically driven by coronal mass ejections (CMEs) from the Sun. Here, we conduct a case study of a type II radio burst that is associated with a C4.5 class flare and a…

Solar and Stellar Astrophysics · Physics 2023-07-04 Zhenyong Hou , Hui Tian , Wei Su , Maria S. Madjarska , Hechao Chen , Ruisheng Zheng , Xianyong Bai , Yuanyong Deng

Centrally located diffuse radio emission has been observed in both merging and non-merging galaxy clusters. Depending on their morphology and size, we distinguish between giant radio haloes, which occur predominantly in merging clusters,…

D-H type II radio bursts are widely thought to be caused by the coronal mass ejections (CMEs). However, it is still unclear where the exact source of the type IIs on the shock surface is. We identify the source regions of the…

Solar and Stellar Astrophysics · Physics 2015-06-11 Chenglong Shen , Chijian Liao , Yuming Wang , Pinzhong Ye , Shui Wang

We have studied a complex metric radio event which originated in a compact flare, observed with the ARTEMIS-JLS radiospectro-graph on February 12, 2010. The event was associated with a surge observed at 195 and 304 {\AA} and with a coronal…

Solar and Stellar Astrophysics · Physics 2021-10-20 C. E. Alissandrakis , A. Nindos , S. Patsourakos , A. Hillaris

Collisionless shock waves, ubiquitous in the universe, are crucial for particle acceleration in various astrophysical systems. Currently, the heliosphere is the only natural environment available for their in situ study. In this work, we…

During solar flares a large amount of electrons with energies greater than 20 keV is generated with a production rate of typically $10^{36}$ s$^{-1}$. A part of them is able to propagate along open magnetic field lines through the corona…

Solar and Stellar Astrophysics · Physics 2015-11-11 F. Breitling , G. Mann , C. Vocks

Fast radio bursts are extragalactic, sub-millisecond radio impulses of unknown origin [1,2]. Their dispersion measures, which quantify the observed frequency-dependent dispersive delays in terms of free-electron column densities,…

High Energy Astrophysical Phenomena · Physics 2019-07-16 Vikram Ravi