The Theory of Solar Radio Bursts: Can it be understood by the Non-Expert?

1981 ◽  
Vol 4 (2) ◽  
pp. 139-144 ◽  
Author(s):  
D. B. Melrose
Keyword(s):  
Observational Data ◽  
Solar Radio ◽  
Solar Physics ◽  
Plasma Instabilities ◽  
The Sun ◽  
Radio Bursts ◽  
Wave Interactions ◽  
Solar Radio Bursts ◽  
Dynamic Spectra ◽  
Time Structures

The theory of solar radio bursts remains a mystery to most astronomers and astrophysicists. The reasons for this are not hard to identify. First, the solar radioastronomical data are unfamiliar. (The observational data on solar radio bursts is being reviewed separately at this meeting (McLean 1981).) The important features of this data involve frequency-time structures in dynamic spectra, and such features are absent in data on galactic and extra galactic objects. Even for pulsars the data are obtained at discrete frequencies, and the frequency-time structures are not of major importance. Second, the theory itself involves plasma physical concepts which are unfamiliar to most physicists and astronomers. These concepts include those of plasma instabilities, microturbulence, and of particle-wave and wave-wave interactions. Third, one must also admit that there is a prejudice amongst many astronomers against solar physics: the Sun is regarded as interesting only to the extent that it can teach us about other astronomical objects. I shall return to this third point later.

The Jupiter Radio Bursts

1974 ◽  
Vol 2 (5) ◽  
pp. 236-243 ◽  
Author(s):  
G. R. A. Ellis
Keyword(s):  
Time Resolution ◽  
Time Scale ◽  
Solar Radio ◽  
Complex Structure ◽  
High Time Resolution ◽  
The Sun ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Physical Scale ◽  
Dynamic Spectra

Like the strong non-thermal radio bursts from the solar corona and from the earth’s magnetosphere, the Jupiter radio bursts are characterized by their duration which may be from milliseconds to seconds, and by their complex structure on the frequency-time plane. In addition, they exhibit a variety of periodicities in their rate of occurrence, the primary one of which is associated with the rotation of Jupiter. The smaller physical scale of Jupiter compared with the Sun naturally leads to a much shorter time scale in the various radio phenomena and it is only recently that suitable equipment has become available to permit the detailed investigation of the dynamic spectra of the bursts with the necessary high time resolution of the order of 10–3 sec (Ellis 1973a,b,c). As in the case of the solar radio bursts, a number of distinct types of dynamic spectra are observed and they provide a convenient basis for classification.

A Preliminary Study of the Dynamic Spectra of Solar Radio Bursts in the Frequency Range 500-950 Mc/s.

1961 ◽  
Vol 133 ◽  
pp. 243 ◽  
Author(s):  
C. W. Young ◽  
C. L. Spencer ◽  
G. E. Moreton ◽  
J. A. Roberts
Keyword(s):  
Solar Radio ◽  
Radio Bursts ◽  
Frequency Range ◽  
Solar Radio Bursts ◽  
Dynamic Spectra ◽  
Preliminary Study

scholarly journals Electron acceleration and radio emission following the early interaction of two coronal mass ejections

2020 ◽  
Vol 642 ◽  
pp. A151
Author(s):  
D. E. Morosan ◽  
E. Palmerio ◽  
J. E. Räsänen ◽  
E. K. J. Kilpua ◽  
J. Magdalenić ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Radio Emission ◽  
Coronal Mass Ejections ◽  
Solar Radio ◽  
Electron Beams ◽  
Solar Radio Emission ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Dynamic Spectra

Context. Coronal mass ejections (CMEs) are large eruptions of magnetised plasma from the Sun that are often accompanied by solar radio bursts produced by accelerated electrons. Aims. A powerful source for accelerating electron beams are CME-driven shocks, however, there are other mechanisms capable of accelerating electrons during a CME eruption. So far, studies have relied on the traditional classification of solar radio bursts into five groups (Type I–V) based mainly on their shapes and characteristics in dynamic spectra. Here, we aim to determine the origin of moving radio bursts associated with a CME that do not fit into the present classification of the solar radio emission. Methods. By using radio imaging from the Nançay Radioheliograph, combined with observations from the Solar Dynamics Observatory, Solar and Heliospheric Observatory, and Solar Terrestrial Relations Observatory spacecraft, we investigate the moving radio bursts accompanying two subsequent CMEs on 22 May 2013. We use three-dimensional reconstructions of the two associated CME eruptions to show the possible origin of the observed radio emission. Results. We identified three moving radio bursts at unusually high altitudes in the corona that are located at the northern CME flank and move outwards synchronously with the CME. The radio bursts correspond to fine-structured emission in dynamic spectra with durations of ∼1 s, and they may show forward or reverse frequency drifts. Since the CME expands closely following an earlier CME, a low coronal CME–CME interaction is likely responsible for the observed radio emission. Conclusions. For the first time, we report the existence of new types of short duration bursts, which are signatures of electron beams accelerated at the CME flank. Two subsequent CMEs originating from the same region and propagating in similar directions provide a complex configuration of the ambient magnetic field and favourable conditions for the creation of collapsing magnetic traps. These traps are formed if a CME-driven wave, such as a shock wave, is likely to intersect surrounding magnetic field lines twice. Electrons will thus be further accelerated at the mirror points created at these intersections and eventually escape to produce bursts of plasma emission with forward and reverse drifts.

The intrinsic relation between envelope solitons and plasma instabilities

2000 ◽  
Vol 64 (3) ◽  
pp. 249-254 ◽  
Author(s):  
GUANGLI HUANG
Keyword(s):  
Solar Radio ◽  
Nonlinear Term ◽  
Plasma Instabilities ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Linear Dispersion ◽  
One Dimensional ◽  
Linear Dispersion Relation ◽  
Envelope Solitons ◽  
The One

A general form of the one-dimensional nonlinear Schrödinger equation is derived; the coefficients depend mainly on the linear dispersion relation, as does the nonlinear term. Envelope solitons may only exist together with some plasma instabilities. An example of solar radio bursts is selected as evidence for envelope solitons in the electromagnetic waveband.

Pecularities of the Dynamic Spectra of Type V Solar Radio Bursts

1980 ◽  
pp. 277-280
Author(s):  
L. M. Bakunin ◽  
A. K. Markeev ◽  
V. V. Fomichev ◽  
I. M. Chertok
Keyword(s):  
Solar Radio ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Dynamic Spectra ◽  
Type V

Using supervised machine learning to automatically detect type II and III solar radio bursts

2020 ◽  
Author(s):  
Eoin Carley
Keyword(s):  
Machine Learning ◽  
Radio Burst ◽  
Solar Radio ◽  
Machine Learning Algorithms ◽  
Supervised Machine Learning ◽  
Radio Bursts ◽  
Type Ii ◽  
Solar Radio Bursts ◽  
Dynamic Spectra

<p>Solar flares are often associated with high-intensity radio emission known as `solar radio bursts' (SRBs). SRBs are generally observed in dynamic spectra and have five major spectral classes, labelled type I to type V depending on their shape and extent in frequency and time. Due to their morphological complexity, a challenge in solar radio physics is the automatic detection and classification of such radio bursts. Classification of SRBs has become necessary in recent years due to large data rates (3 Gb/s) generated by advanced radio telescopes such as the Low Frequency Array (LOFAR). Here we test the ability of several supervised machine learning algorithms to automatically classify type II and type III solar radio bursts. We test the detection accuracy of support vector machines (SVM), random forest (RF), as well as an implementation of transfer learning of the Inception and YOLO convolutional neural networks (CNNs). The training data was assembled from type II and III bursts observed by the Radio Solar Telescope Network (RSTN) from 1996 to 2018, supplemented by type II and III radio burst simulations. The CNNs were the best performers, often exceeding >90% accuracy on the validation set, with YOLO having the ability to perform radio burst burst localisation in dynamic spectra. This shows that machine learning algorithms (in particular CNNs) are capable of SRB classification, and we conclude by discussing future plans for the implementation of a CNN in the LOFAR for Space Weather (LOFAR4SW) data-stream pipelines.</p>

A Comparison of the Dynamic Spectra of Solar Radio Bursts in the Decimeterand Meter-Wave Ranges.

1961 ◽  
Vol 133 ◽  
pp. 255 ◽  
Author(s):  
M. R. Kundu ◽  
J. A. Roberts ◽  
C. L. Spencer ◽  
J. W. Kuiper
Keyword(s):  
Solar Radio ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Dynamic Spectra

scholarly journals The Positions and Movements of the Sources of Solar Radio Bursts of Spectral Type II

1963 ◽  
Vol 16 (2) ◽  
pp. 240 ◽  
Author(s):  
AA Weiss
Keyword(s):  
Spectral Type ◽  
Solar Radio ◽  
Radio Bursts ◽  
Type Ii ◽  
Frequency Range ◽  
Solar Radio Bursts ◽  
Dynamic Spectra ◽  
Type Ii Radio Bursts ◽  
Optical Flare ◽  
East West

The east-west position coordinates of the sources of 22 type II radio bursts, measured in the range 40-70 Mc/s using a swept-frequency interferometer, are analysed and discussed, in conjunction with dynamic spectra obtained in the frequency range 15-210 Mc/s. Many bursts are multiple and consist of a number of separate bursts excited by disturbances ejected in different directions from the vicinity of an optical flare, which may be equally complex.

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