Solar radio bursts (SRBs) are sudden peaks in the low-frequency radio emissions originating from the sun. These emissions can also help predict space weather events that could have adverse e… Read More
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Solar Radio Astronomy Blog
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The Highlights of Solar Radio Physics (science nuggets) are short communications written in the language accessible to a non-expert in the specific area. The nugget is a brief description of a new and interesting scientific result, not as detailed as a scientific article, but rather written in a more discursive ‘news & views’ style.
Inelastic scattering off moving or oscillating density fluctuations leads to broadening of radio signals propagating in the solar corona and solar wind. Using an anisotropic density fluctuat… Read More
Here we release the spectral data of solar radio bursts recorded by the Chashan Broadband Solar radio spectrograph (CBSm), located in the Chashan mountain (E122°.30, N36°.84) that is… Read More
Polarization, regardless of wavelength, is one of the key observables for understanding the solar atmosphere because it provides information about magnetic fields, and microwave polarization… Read More
Since the discovery of solar radio emission in the late 1940s, the Sun has been studied in great detail across a wide range of frequencies from a few tens of kHz to several hundreds of GHz… Read More
The study of solar wind acceleration and coronal heating has been a major challenge in solar physics. The main difficulty is that the collisionless characteristic of high-temperature, thin… Read More
The turbulent heliosphere has a significant effect on the observed characteristics of radio emission produced in, or viewed through, the solar atmosphere. In particular, radio-wave scatterin… Read More
Recent years, several new generation solar radio telescopes operating in the centimeter decimeter (dm-cm) wavelengths have emerged in the world, including the Mingantu Spectral Radioheliogra… Read More
Interplanetary solar radio type III bursts provide the means to remotely study and track energetic electrons propagating in the interplanetary medium. Due to the lack of direct radio source… Read More
Density turbulence in the solar corona and solar wind is evident via the properties of solar radio bursts; angular scattering-broadening of extra-solar radio sources observed through the sol… Read More
During times of high solar activity flares and coronal mass ejections (CMEs) occur close in time, sometimes even simultaneously, and it may be difficult to identify their source regions. Esp… Read More
Coronal mass ejections (CMEs) are large-scale expulsion of plasma and magnetic fields from the solar corona into the heliosphere. Magnetic field entrained in the CME plasma is crucial to und… Read More
In the decimeter to centimeter wavelength, solar radio emission during bursts are generally accepted to be generated by gyrosynchrotron. The typical gyrosynchrotron spectra present reverse-V… Read More
Type II solar bursts are radio signatures of shock waves in the solar corona driven by solar flares or coronal mass ejections. Therefore, these bursts present complex spectral morphologies i… Read More
A long-standing problem in solar energetic particle (SEP) studies is to pinpoint their source regions at the Sun. Potential contributions by both the flare and CME-driven shocks complicate t… Read More
Solar radio emission can be significantly influenced by Earth’s atmosphere when transmitting towards the Earth’s surface, due to atmospheric turbulence and the absorption of vapo… Read More
Solar accelerated electron beams interact with the background plasma of the solar wind to locally generate Langmuir waves and subsequently produce radio emission (Ginzburg and Zhelezniakov 1… Read More
In the dynamic realm of modern solar physics, where vast and diverse data sets challenge understanding, a critical need emerges for advanced data-constrained 3D modeling that combines photos… Read More
Solar radio pulsations represent (quasi-)periodic or irregular short fluctuations observed from the radio flux curves or the dynamic spectra, in almost all wavelength ranges from metric to m… Read More
Solar flares are known to be prolific electron accelerators, yet identifying the mechanism(s) for such efficient electron acceleration in magnetic reconnection events at the Sun (and similar… Read More
We are striving for more accurate coronal magnetography based on changes in radio polarization as microwaves cross magnetic field lines at nearly right angles.
The theory of using quasi-tran… Read More
Solar radio spikes’ most typical observational features are their short duration and narrow bandwidth. They appear on the solar radio dynamic spectrogram as a large number of narrow-ba… Read More
Radio bursts are frequently emitted in the outer solar corona due to the acceleration of energetic electrons in solar flares and coronal mass ejections (CME). The shortest observed bursts ar… Read More
One important task connected with the corona heating problem is exploring the physical mechanisms that produce, accelerate, and transport energetic particles in the upper corona. The magneti… Read More
Solar type II radio bursts appear in the spectrograph records as slowly drifting emission lanes from high to low frequencies. They are due to plasma oscillations caused by the electrons acce… Read More
Solar radio bursts generated through the plasma emission mechanism produce radiation near the local plasma frequency (fundamental emission, hereafter, F) and double the plasma frequency (har… Read More
The Parker Solar Probe (PSP) has enabled unprecedented opportunity to study the plasma and magnetic field properties of the solar wind from near the Earth (~1 au radial distance r) to very c… Read More
The present Special Issue published in Advances of Space Research contains a collection of peer-reviewed contributions that builds on the recent observational and theoretical advances, surve… Read More
Microwave emission of solar flares can be excited by energetic electrons through the gyrosynchrotron (GS) radiation. Thus, the microwave spectra contain valuable/unique information not only… Read More
Comet 2I/Borisov was only the second interstellar object known to have entered the solar system. The highly eccentric, hyperbolic orbit of 2I/Borisov and its high inclination to the ecliptic… Read More
Quasi-periodic pulsations (QPPs; also known as quasi-periodic oscillations, i.e., QPOs) are phenomena that electromagnetic emissions vary quasi-periodically with time. They appear in celesti… Read More
The solar radio zebra patterns, or zebras, provide detailed diagnostics of plasma density and magnetic field in the corona. The zebras appear in radiograms during Type IV solar radio bu… Read More
The (sub)millimeter radiation of solar flares, explosive events detected as brightenings across the electromagnetic spectrum, is poorly understood (Krucker et al. 2013). The major limit of t… Read More
Electromagnetic emissions at the third harmonic of the plasma frequency $\omega _{p}$ have been reported during the occurrence of type II and type III solar radio bursts (e.g. Zlotnik 1978… Read More
Investigating the generation mechanism for the stripes-pattern radio spectra is important to understand the dynamics of non-thermal electrons in several astronomical objects, including the S… Read More
The solar radio spikes can provide detailed information about plasma processes in solar flares on kinetic scales. Among them, the decimetric spikes belong to the most interesting ones becaus… Read More
The solar corona comprises hot magnetized plasma. Coronal magnetic fields are well known to be one of the crucial parameters determining the physics of the solar corona and are vital drivers… Read More
Practically all solar phenomena observed in radio wavelengths have their counterpart in other regions of the electromagnetic spectrum. Metric solar bursts are an exception to the above state… Read More
We present a short overview on the results from the first association analysis between in situ observed solar energetic electrons at 1 AU using the ACE/EPAM instrument (Samwel and Miteva, 20… Read More
Trieste CALLISTO Station Setup And Observations Of Solar Radio Bursts By A. Marassi And C. Monstein
A solar radio burst (SRB) is the intense solar radio emission often related to a solar flare and one of the possibly extreme space weather events which may affect Earth’s ionosphere an… Read More
Filaments (or prominences) are “clouds” of cool (4 K) material suspended in the solar corona by up to tens of megameters above the photosphere, and they can be broadly divided in… Read More
We investigate angular broadening of radio wave scattering by density irregularities in the outer heliosphere and the very local interstellar medium (VLISM), incorporating an inner scale, la… Read More
Langmuir-Slow extraordinary mode (L-SE) waves have been routinely observed in the Solar wind and in Earth’s electron foreshock since the early age of the space exploration. They are in… Read More
The plasma density and magnetic field in the upper solar corona and inner heliosphere are not sufficient to produce detectable bremsstrahlung hard X-ray or gyrosynchrotron microwave emission… Read More
Solar radio bursts of Type III were currently observed since decades in the interplanetary space (Reid and Ratcliffe, 2014). They result from a series of successive processes arising in sola… Read More
While it is widely accepted that the type II radio bursts observed in the interplanetary medium are due to the coronal mass ejections (CMEs), the energetic disturbance responsible for the sh… Read More
Solar type III radio bursts are produced by electron beams that are propagating along open magnetic field lines in the corona and interplanetary medium (IPM). Type III bursts drift from high… Read More
Harvest Of Scientific Results By Solar Orbiter Radio And Plasma Waves Instrument By Milan Maksimovic
For a mission that has just entered its primary science phase, Solar Orbiter has already produced many remarkable results. Released on December 14, 2021, a special issue of Astronomy and Ast… Read More
Nanoflares are impulsive energy releases due to small breaks in coronal magnetic fields that have become stressed by photospheric convection. They are too small to be detected individually… Read More
The magnetic fields of the Sun govern the solar corona structure where the solar wind emanates and further accelerates supersonically. Therefore, the accurate observational data about the to… Read More
Metrewave solar type-III radio bursts offer a unique means to study the properties of turbulence across coronal heights. Theoretical models have shown that the apparent intensity and size of… Read More
Solar radio radiation is one of the most sensitive emissions during solar eruptions, where type III radio bursts can provide clues for electron acceleration and propagation. Type III radio b… Read More
Solar type II bursts are sporadic emissions characterized by their narrow bandwidth and slow frequency drift in dynamic spectra (Nelson & Melrose, 1985; Vršnak & Cliver 2008;… Read More
Electron cyclotron maser emission (ECME) represents a major class of coherent emission mechanism of solar radio bursts. ECME usually occurs in strongly magnetized plasmas with the frequency… Read More
Commercial dish TV antennas are parabolic structures designed to receive radio waves from a communication satellite. The antennas and the associated front end receiver systems have improved… Read More
Small scale energy releases on the Sun e.g., flaring bright points, active region transient brightenings, etc. have been studied using X-ray and radio observations. The observations of low f… Read More
Solar radio spikes are short duration, narrowband radio bursts that are signature of the acceleration of non-thermal electrons in solar flares. They are observed over a wide range of frequen… Read More
Type II radio bursts are slow-drifting and long-lasting radio emission produced by nonthermal electrons accelerated at shocks propagating through the solar corona and interplanetary medium (… Read More
During encounter 2 of NASA’s PSP mission there was a large amount of radio activity and, in particular, a noise storm of frequent, small type III bursts from 31 March to 6 April 2019… Read More
Langmuir Wave Motion Observed In The Most Intense Radio Sources In The Sky By H. Reid And E. Kontar
The Sun routinely produces energetic electrons in its outer atmosphere that subsequently travel through interplanetary space. These electron beams generate Langmuir waves in the background p… Read More
Quasi-periodic pulsations (QPPs) are defined as intensity modulations in the flare electromagnetic radiation as a function of time. These modulations have been found to have characteristic p… Read More
Coronal mass ejections (CMEs) are large scale and energetic eruptions in the solar atmosphere during which $\approx$10$^{12}$-10$^{16}$g of magnetized coronal plasma are ejected into the hel… Read More
Thermal plasma in the solar corona is often characterized by a range of temperatures. This plasma can be described by the differential emission measure (DEM), which is a distribution of the… Read More
The solar flare phenomenon is a complex process in the solar atmosphere where non-potential magnetic energy is released and converted into other forms of energy, such as nonthermal energy of… Read More
Narrowband dm-spikes belong to the most interesting fine structures of solar radio bursts that are closely connected to primary flare energy-release processes (Krueger 1979) and observed in… Read More
Interplanetary (IP) type III radio bursts are deemed to generate in the interplanetary space because of their lower emission frequency ($0.01 – 10$ MHz) in terms of plasma emission. Ho… Read More
Zebra patterns (ZPs) represent a spectral fine structure with equidistant or almost-equidistant stripes of enhanced intensity against a broadband emission background, frequently observed in… Read More
The imaging and spectroscopy observations of solar radio bursts can provide information on the non-thermal electrons associated with the transient energy release in the solar active region a… Read More
Solar spikes are radio bursts closely associated with the impulsive stage of solar flares. They are characterized by extremely high brightness temperature of up to 1015 K, narrow-band, and s… Read More
Solar noise storms are known to be related to small and large scale magnetic field enhancements at active regions (Elgaroy 1977, Li et al.,2017). However, the mechanism still remain unclear… Read More
In a solar flare, the plasma is locally heated and particles are accelerated to energies from a few tens of keV to MeVs. X-ray bremsstrahlung emission and radio gyrosynchrotron emission are… Read More
EUV (EIT) waves are wavelike disturbances of enhanced extreme ultraviolet (EUV) emission that propagate away from an eruptive region. Recent years have seen much debate over their nature, wi… Read More
Coronal mass ejections are large eruptions of magnetized plasma from the Sun (Webb et. al. 2012) that are often accompanied by radio emission, generated by the energetic electrons produced d… Read More
The Sun is the main source of space weather, and one type of solar event that is critical to space weather is a coronal mass ejection. Coronal mass ejections (CMEs) are large eruptions of ma… Read More
The quiet Sun coronal emission dominantly comes from thermal bremsstrahlung. As this radiation traverses the coronal medium on its way to the Earthbound observer, the coronal optical de… Read More
Weakly turbulent processes of three-wave interactions between Langmuir and electromagnetic waves in plasma with unstable electron flows are believed to be the main cause of type II and III s… Read More
Recent studies (Kontar et al. 2017) of a Type III–IIIb burst observed by LOFAR (van Haarlem et al. 2013) indicated that the temporal variations in the positions and source sizes d… Read More
Type II radio bursts, produced near the local plasma frequency and/or its harmonic by energetic electrons accelerated by shock waves moving outward through the inner heliosphere, have long b… Read More
Radio bursts and their fine structures are an integral part of solar flares. Although many of them are known as e.g. type II, III, V, J, U, and IV, still some unique bursts and fine structur… Read More
Magnetic Reconnection During The Post-impulsive Phase Of A Long-duration Solar Flare By S. Yu Et Al.
Magnetic reconnection, a fundamental process in astrophysical environment plasma is believed to facilitate the release of energy stored in the magnetic field. However, where the magnetic rec… Read More
The shape, size and electron density (Ne) of the corona varies with the sunspot cycle, which is now very well established by white-light observations. In our study, we investigated the &lsqu… Read More
Magnetic flux ropes are believed to be the centerpiece of the three-part structure of coronal mass ejections. In the standard model of eruptive solar flares, flux rope eruption also induces… Read More
A coronal mass ejection (CME) is a phenomenon which produces large-scale ejections of mass and magnetic field from the lower corona into the interplanetary space (e.g. Forbes, 2000). The eje… Read More
Drift-pair bursts are a rare and mysterious type of fine spectral structures in the low-frequency domain of solar radio emission. First identified by Roberts (1958), they appear in the dynam… Read More
Type III radio bursts from the Sun are signatures of energetic (∼1–100 keV) electrons, accelerated at the reconnection sites, propagating upward through the corona into the interpl… Read More
Solar flares are characterized by fast plasma flows. In such plasma flows owing to the Kelvin-Helmholtz instability the maqnetohydrodynamic turbulence can be generated. Although, the tu… Read More
The solar community has been trying to understand the mechanism responsible for coronal heating for several decades now. In the past decade, a number of studies have shown that the active re… Read More
CMEs can be the sources of space-weather disturbances. Shock waves expanding ahead of fast CMEs and associated flares are the probable sources of energetic protons. Two categories of CMEs ha… Read More
Type II solar radio bursts are believed to be excited by shock waves. They are often linked to shocks driven by solar eruptive events like Coronal Mass Ejections (CMEs) and solar flares, and… Read More
Flare accelerated electrons emit light from X-rays to radio waves, which sometimes show highly regular and periodic intensity pulsations (Nakariakov et al. 2009). However, the processes that… Read More
Microwave solar polarization observations give us information about the magnetic field of the solar atmosphere. They are important for understanding the various solar activity phenomena and… Read More
Magnetic reconnection is a key process in astrophysical and space plasmas that converts magnetic energy into other forms of energy. It drives gamma-ray bursts, solar flares, and accelerates… Read More
Type III bursts belong among the strongest radio signals routinely observed by both space-borne and ground-based instrumentations. They are generated via the plasma emission mechanism, when… Read More
Solar flares, similar to many other astrophysical energetic processes, are related to magnetic reconnection. During these events magnetic energy is transferred from other forms of energy, mo… Read More
Solar eruptive phenomena, such as flares and coronal mass ejections (CMEs), generate high-energy particles called solar energetic particles (SEPs). Severe SEP events sometimes cause satellit… Read More
Observations in the ultraviolet (UV) taken with the Interface Region Imaging Spectrograph (IRIS) have shown that the bright magnetic patches, known as plage, typically feature broader and br… Read More
Estimating the kinematics of Type II radio-burst sources, which are recognized as a shock waves, using electron-density models is inaccurate and restricted. In this article, a blast-expansio… Read More
Type III radio bursts are generated by non-thermal electron beams propagating through the solar corona and interplanetary space. In dynamic spectra, the flux of solar type III radio bursts h… Read More
Wild (1950) was the first to register and describe Type III bursts properties. These bursts are tracks of radio emission, which drift from high frequencies to low frequencies. Profiles of Ty… Read More
Drift pairs are a rare and puzzling type of solar radio emission, firstly identified by Roberts (1958). They occur at low frequencies (~10-100 MHz) and look like two parallel frequency-drift… Read More