PREDICTION OF TYPE II SOLAR RADIO BURSTS BY THREE-DIMENSIONAL MHD CORONAL MASS EJECTION AND KINETIC RADIO EMISSION SIMULATIONS

2013 ◽  
Vol 773 (2) ◽  
pp. L30 ◽  
Author(s):  
J. M. Schmidt ◽  
Iver H. Cairns ◽  
D. S. Hillan
Keyword(s):  
Radio Emission ◽  
Coronal Mass Ejection ◽  
Solar Radio ◽  
Three Dimensional ◽  
Radio Bursts ◽  
Type Ii ◽  
Solar Radio Bursts ◽  
Mass Ejection

Type II Solar Radio Bursts over Solar Cycle 21

1994 ◽  
Vol 144 ◽  
pp. 283-284
Author(s):  
G. Maris ◽  
E. Tifrea
Keyword(s):  
Solar Radio ◽  
Interplanetary Space ◽  
Impulsive Phase ◽  
Radio Bursts ◽  
Type Ii ◽  
Solar Radio Bursts ◽  
Strong Energy ◽  
Mass Ejection ◽  
Geophysical Effect ◽  
Radio Event

The type II solar radio bursts produced by a shock wave passing through the solar corona are one of the most frequently studied solar activity phenomena. The scientific interest in this type of phenomenon is due to the fact that the presence of this radio event in a solar flare is an almost certain indicator of a future geophysical effect. The origin of the shock waves which produce these bursts is not at all simple; besides the shocks which are generated as a result of a strong energy release during the impulsive phase of a flare, there are also the shocks generated by a coronal mass ejection or the shocks which appear in the interplanetary space due to the supplementary acceleration of the solar particles.

scholarly journals On the Issue of the Origin of Type II Solar Radio Bursts

2021 ◽  
Vol 922 (1) ◽  
pp. 82
Author(s):  
Gennady Chernov ◽  
Valery Fomichev
Keyword(s):  
Shock Waves ◽  
Radio Emission ◽  
Solar Atmosphere ◽  
Solar Radio ◽  
Radio Bursts ◽  
Type Ii ◽  
Solar Radio Bursts ◽  
Type Ii Radio Bursts ◽  
Type Ii Bursts ◽  
The Relationship

Abstract Type II solar radio bursts are among the most powerful events in the solar radio emission in the meter wavelength range. It is generally accepted that the agents generating type II radio bursts are magnetohydrodynamic shock waves. But the relationship between the shock waves and the other manifestations of the large-scale disturbances in the solar atmosphere (coronal mass ejections, Morton waves, EUW waves) remains unclear. To clarify a problem, it is important to determine the conditions of generation of type II radio bursts. Here, the model of the radio source is based on the generation of radio emission within the front of the collisionless shock wave where the Buneman instability of plasma waves is developed. In the frame of this model, the Alfvén magnetic Mach number must exceed the critical value, and there is a strict restriction on the perpendicularity of the front. The model allows us to obtain the information about the parameters of the shock waves and the parameters of the medium by the parameters of type II bursts. The estimates, obtained in this paper for several events with the band splitting of the fundamental and harmonic emission bands of the type II bursts, confirm the necessary conditions of the model. In this case the registration of type II radio bursts is an indication of the propagation of shock waves in the solar atmosphere, and the absence of type II radio bursts is not an indication of the absence of shock waves. Such a situation should be taken into account when investigating the relationship between type II radio bursts and other manifestations of solar activity.

Higher Harmonic Plasma Radiation in Type II Solar Radio Bursts

1990 ◽  
pp. 517-518
Author(s):  
V. V. Fomichev ◽  
I. M. Chertok ◽  
R. V. Gorgutsa ◽  
A. K. Markeev ◽  
B. Kliem ◽  
...  
Keyword(s):  
Solar Radio ◽  
Plasma Radiation ◽  
Radio Bursts ◽  
Type Ii ◽  
Solar Radio Bursts ◽  
Higher Harmonic

scholarly journals The correlation of solar radio bursts by magnetic activity and cosmic rays

1959 ◽  
Vol 9 ◽  
pp. 210-213
Author(s):  
A. R. Thompson
Keyword(s):  
Cosmic Rays ◽  
Radio Astronomy ◽  
Solar Radio ◽  
Magnetic Activity ◽  
Radio Bursts ◽  
Type Ii ◽  
Frequency Range ◽  
Sweep Frequency ◽  
Solar Radio Bursts ◽  
Auroral Particles

The sweep-frequency equipment at the Harvard Radio Astronomy Station, Fort Davis, Texas, has now been running continuously since 1956 September, recording solar radio activity in the frequency range from 100 to 580 Mc/s. The following contribution describes preliminary investigations of the correlation of the radio data with solar corpuscular emissions. This work was initiated to examine the well-known suggestions that the origins of the type II and type III radio bursts are associated with the ejection of auroral particles and cosmic rays respectively.

scholarly journals Recent Results of Meter-decameter Wave Observations of Solar Flares

1989 ◽  
Vol 104 (2) ◽  
pp. 185-189
Author(s):  
N. Copalswamy ◽  
M. R. Kundu
Keyword(s):  
Solar Flares ◽  
Solar Radio ◽  
Radio Bursts ◽  
Type Ii ◽  
Solar Radio Bursts ◽  
Type Iii ◽  
Type Iv

AbstractWe present recent results from meter-decameter imaging of several classes of solar radio bursts: Preflare activity in the form of type III bursts, correlated type IIIs from distant sources, and type II and moving type IV bursts associated with flares and CMEs.

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.

scholarly journals Type II solar radio bursts: 2. Detailed comparison of theory with observations

2012 ◽  
Vol 117 (A6) ◽  
pp. n/a-n/a ◽  
Author(s):  
D. S. Hillan ◽  
Iver H. Cairns ◽  
P. A. Robinson
Keyword(s):  
Solar Radio ◽  
Detailed Comparison ◽  
Radio Bursts ◽  
Type Ii ◽  
Solar Radio Bursts

scholarly journals Separation of solar radio bursts in a complex spectrum

2010 ◽  
Vol 6 (S274) ◽  
pp. 150-152
Author(s):  
Hana Mészárosová ◽  
Ján Rybák ◽  
Marian Karlický ◽  
Karel Jiřička
Keyword(s):  
Radio Emission ◽  
Current Sheet ◽  
Solar Flares ◽  
Solar Radio ◽  
Radio Spectrum ◽  
New Method ◽  
Complex Spectrum ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Fine Structures

AbstractRadio spectra, observed during solar flares, are usually very complex (many bursts and fine structures). We have developed a new method to separate them into individual bursts and analyze them separately. The method is used in the analysis of the 0.8–2.0 GHz radio spectrum of the April 11, 2001 event, which was rich in drifting pulsating structures (DPSs). Using this method we showed that the complex radio spectrum consists of at least four DPSs separated with respect to their different frequency drifts (−115, −36, −23, and −11 MHz s−1). These DPSs indicate a presence of at least four plasmoids expected to be formed in a flaring current sheet. These plasmoids produce the radio emission on close frequencies giving thus a mixture of superimposed DPSs observed in the radio spectrum.

A Unified Model of Coronal Mass Ejection–related Type II Radio Bursts

2000 ◽  
Vol 538 (2) ◽  
pp. L175-L178 ◽  
Author(s):  
Tetsuya Magara ◽  
Pengfei Chen ◽  
Kazunari Shibata ◽  
Takaaki Yokoyama
Keyword(s):  
Coronal Mass Ejection ◽  
Unified Model ◽  
Radio Bursts ◽  
Type Ii ◽  
Type Ii Radio Bursts ◽  
Mass Ejection
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