CONNECTION OF THE INTENSITY OF THE FLUX OF SCR PROTONS WITH THE VELOCITY OF THE CME AND WITH THE FADING OF THE RADIO EMISSION OF THE SUN IN THE DECAMETER RANGE

The relationship between SCR and CME and with fading of the continuum of noise storms and typeIV radio bursts in the decameter range is investigated. It was shown earlier that about 60% of CMEs associated with solar proton events are accompanied by deep fading of the solar radio emission in the decameter range, which coin-cides in time with CME registration. It has also been shown that fading is characterized by fading depth, the frequency bandwidth in which the fading occurs, as well as the duration of the fading and the frequency at which the maximum fading depth is observed. Further detailed studies have shown that for proton events accompanied by fading of the solar radio emission in the decameter range, the relationship between the intensity of the SCR proton flux and the CME velocity is much worse than for events without fading of the solar radio emission in the decameter range. However, it was foundthat for such events, the relationship between the flux of SCR protons and the CME velocity significantly increases if we take into account the fading depth of the solar radio emission in the decameter range.Earlier in (Isaeva, 2019), the results of a study of the relationship between the intensity of fading of the continuum of noise storms with the parameters of X-ray bursts, with the CME velocity and the velocity of coronal shock waves, as well as with the intensity of the SCR proton flux were presented. This paper presents the results of studying the relationship between the intensity of the SCR proton flux withthe parameters of type II and IV radio bursts, as well as with the CME velocity and with the velocity of coronal shock waves, depending on the intensity of fading of the solar radio emission in the decameter range at a frequency of 27 MHz. The frequency of 27 MHz was chosen because in the region of this frequency the maximum fading depth of the solar radio emission in the decameter range is observed.

Download Full-text

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

The Astrophysical Journal ◽

10.3847/1538-4357/ac1f32 ◽

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.

Download Full-text

RELATIONSHIP OF SCR, CME AND CORONAL SHOCK WAVES WITH THE PARAMETERS OF TYPE IV AND II SOLAR RADIO BURSTS

Odessa Astronomical Publications ◽

10.18524/1810-4215.2020.33.216446 ◽

2020 ◽

Vol 33 (0) ◽

pp. 79-84

Author(s):

E. A. Isaeva

Keyword(s):

Shock Waves ◽

Solar Radio ◽

Radio Bursts ◽

Solar Radio Bursts ◽

Type Iv ◽

Coronal Shock ◽

Relationship Of

Download Full-text

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

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038801 ◽

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.

Download Full-text

The relationship between the slowly varying component of solar radio emission and large scale photospheric magnetic field patterns

Solar Physics ◽

10.1007/bf00151958 ◽

1974 ◽

Vol 35 (2) ◽

pp. 361-368 ◽

Cited By ~ 6

Author(s):

P. H. Scherrer ◽

M. El-Raey

Keyword(s):

Magnetic Field ◽

Radio Emission ◽

Large Scale ◽

Solar Radio ◽

Photospheric Magnetic Field ◽

Solar Radio Emission ◽

Field Patterns ◽

The Relationship

Download Full-text

On the fine structures in interplanetary radio emissions

10.5194/egusphere-egu2020-1025 ◽

2020 ◽

Author(s):

Immanuel Christopher Jebaraj ◽

Jasmina Magdalenic ◽

Stefaan Poedts

Keyword(s):

Magnetic Field ◽

Radio Emission ◽

Radio Source ◽

Solar Radio ◽

Wind Waves ◽

Solar Radio Emission ◽

Radio Bursts ◽

Type Ii ◽

Type Iii ◽

Fine Structures

<p>Solar radio emission is studied for many decades and a large number of studies have been dedicated to metric radio emission originating from the low corona. It is generally accepted that solar radio emission&#160; observed at wavelengths below the metric range is produced by the coherent plasma emission mechanism. Fine structures seem to be an intrinsic part of solar radio emission and they are very important for understanding plasma processes in the solar medium. Extensive reporting and number of studies of the metric range fine structures were performed, but studies of fine structures in the interplanetary domain are quite rare. New and advanced ground-based radio imaging spectroscopic techniques (e.g. LOFAR, MWA, etc.,) and space-based observations (Wind/WAVES, STEREO/WAVES A & B, PSP, and SolO in the future) provide a unique opportunity to study radio fine structures observed&#160; all the way from metric to kilometric range.</p><p>Radio signatures of solar eruptive events, such as flares and CMEs, observed in the interplanetary space are mostly confined to type II (radio signatures of magneto-hydrodynamic shock waves), and type III&#160; bursts(electron beams propagating along open and quasi-open magnetic field lines). In this study, we have identified, and analyzed three types of fine structures present within the interplanetary radio bursts. Namely, the striae-like fine structures within type III bursts, continuum-like emission patches, and very slow drifting narrowband structures within type II radio bursts. Since space-based radio observations are limited to dynamic spectra, we use the novel radio triangulation technique employing direction finding measurements from stereoscopic spacecraft (Wind/WAVES, STEREO/WAVES A & B) to obtain the 3D position of the radio emission. The novelty of the technique is that it is not dependent on a density model and in turn can probe the plasma density in the triangulated radio source positions (Magdalenic et al. 2014). Results of the study show that locating the radio source helps not only to understand the generation mechanism of the fine structures but also the ambient plasma conditions such as e.g. electron density. We found that fine structures are associated with complex CME/shock wave structures which interact with the ambient magnetic field structures. We also discuss the possible relationship between the fine structures, the broadband emission they are part of, and the solar eruptive events they are associated with.</p>

Download Full-text

On the Association of Solar Radio Emission and Solar Prominences

Australian Journal of Physics ◽

10.1071/ph560315 ◽

1956 ◽

Vol 9 (3) ◽

pp. 315 ◽

Cited By ~ 19

Author(s):

JP Wild ◽

H Zirin

Keyword(s):

Radio Emission ◽

Solar Radio ◽

Solar Radio Emission ◽

Radio Bursts ◽

Sacramento Peak ◽

Solar Prominences

Prominence cinematograms made at Sacramento Peak and climax in the years 1949?55 have been examined and compared with the solar radio records at 167 Mc/s. No close connexion was found between limb events and radio events, but some eruptions were found to be associated with simultaneous radio bursts. Three such cases are discussed in detail.

Download Full-text