Possible Causes of Line Splitting in Drift Pair Solar Bursts

1971 ◽  
Vol 2 (1) ◽  
pp. 56-57 ◽  
Author(s):  
D. B. Melrose ◽  
W. Sy
Keyword(s):  
Electromagnetic Waves ◽  
Solar Radio ◽  
Plasma Frequency ◽  
Plasma Waves ◽  
Electron Plasma ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Basic Model ◽  
Line Splitting ◽  
Solar Bursts

In this paper possible causes of line splitting in emission near the local plasma frequency are considered in connection with drift pair solar radio bursts. The basic model envisaged for the bursts involves a bunch of electrons streaming through the solar corona at several times the thermal velocity of electrons. The emission process assumed is the transformation of coherently generated electron plasma waves (I-waves) into electromagnetic waves (t-waves) with little change in frequency.

scholarly journals On the Theory of Type II and Type III Solar Radio Bursts. I. The Impossibility of Nonthermal Emission due to Combination Scattering Off Thermal Fluctuations

1970 ◽  
Vol 23 (5) ◽  
pp. 871 ◽  
Author(s):  
DB Melrose
Keyword(s):  
Solar Radio ◽  
Plasma Waves ◽  
Thermal Fluctuations ◽  
Electron Plasma ◽  
Radio Bursts ◽  
Type Ii ◽  
Solar Radio Bursts ◽  
Charge Fluctuations ◽  
Nonthermal Emission ◽  
Combination Scattering

Combination scattering as proposed by Ginzburg and Zhelezniakov involves the coalescence of electron plasma waves from a nonthermal distribution with electron plasma waves from the distribution of thermal charge fluctuations. Reabsorption is neglected.

scholarly journals On the Propagation of the Electrons Related to Type III Bursts

1980 ◽  
Vol 86 ◽  
pp. 327-327 ◽  
Author(s):  
G.V. de Genouillac ◽  
D.F. Escande
Keyword(s):  
Solar Corona ◽  
Electromagnetic Waves ◽  
Solar Radio ◽  
Interplanetary Medium ◽  
Electron Plasma ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Plasma Oscillations ◽  
Type Iii ◽  
Electron Clouds

Type III solar radio bursts are known to be excited by solar electron clouds travelling outwards through the solar corona and interplanetary medium. According to the “plasma hypothesis”, electron plasma oscillations are created by the passing beam, which are in turn converted into electromagnetic waves.

scholarly journals Numerical Simulation of Type III Bursts

1980 ◽  
Vol 86 ◽  
pp. 299-302
Author(s):  
T. Takakura
Keyword(s):  
Numerical Simulation ◽  
Analytical Method ◽  
Solar Radio ◽  
Plasma Waves ◽  
Radio Bursts ◽  
Emission Mechanism ◽  
Normal Type ◽  
Solar Radio Bursts ◽  
Radio Emissions ◽  
Type Iii

By the use of semi-analytical method, modeling of three kinds of type III solar radio bursts have been made. Many basic problems about the type III bursts and associated solar electrons have been solved showing some striking or unexpected results. If the fundamental radio emissions should be really observed as the normal type III bursts, the emission mechanism would not be the currently accepted one, i.e. the scattering of plasma waves by ions.

Entropy and the Spontaneous Emission of Plasma Waves

1977 ◽  
Vol 3 (2) ◽  
pp. 174-177
Author(s):  
R. J. M. Grognard
Keyword(s):  
Time Domain ◽  
Solar Radio ◽  
Plasma Waves ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Self Consistent ◽  
The Time Domain ◽  
Astrophysical Research ◽  
Secular Terms ◽  
Domain Of Validity

The emission of plasma waves by beams of electrons travelling in a plasma is a phenomenon of critical importance in applied plasma physics (for instance in problems directly related to the achievement of controlled nuclear fusion) and also astrophysical research (e.g. in the theory of solar radio bursts). In principle, the mechanisms involved are all contained in the Boltzmann-Vlasov equation, where the field is the self-consistent electromagnetic field produced by the interaction between beam and plasma. Unfortunately this celebrated equation cannot be solved directly, because both the analytical and numerical methods that can deal with this equation are plagued by secular terms which restrict the time domain of validity of the solutions to a few thousand plasma periods. In all applications of interest this domain is far too small; indeed in all astrophysical cases it is quite negligible compared with the duration of the observed phenomena (it is even much shorter than the time resolution of present-day equipment, such as dynamic spectrographs).

scholarly journals The Application of Coronal Scattering Measurements to Solar Radio Bursts

1980 ◽  
Vol 86 ◽  
pp. 265-268
Author(s):  
Henry M. Bradford
Keyword(s):  
Plasma Frequency ◽  
Sunspot Cycle ◽  
Scattering Data ◽  
The Sun ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
The Past ◽  
Solar Bursts ◽  
Density Inhomogeneities ◽  
Insufficient Knowledge

The interpretation of ground based observations of solar “plasma frequency” radio bursts has been hampered in the past by an insufficient knowledge of coronal scattering by density inhomogeneities close to the sun. Calculations based on measurements of the angular broadening of natural radio sources, and Woo's 1975 measurement of the angular broadening of the telemetry carrier of Helios I near occultation (Woo, 1978), indicate that plasma frequency solar bursts should undergo considerable scattering, at least near the maximum of the sunspot cycle. The calculated displacements of the apparent positions of the bursts are about equal to the observed displacements which have been attributed to the bursts occurring in dense streamers. In order to obtain more scattering data close to the sun, interferometer measurements of the angular broadening of spacecraft signals are planned, and the important contribution which could be made with large dishes is discussed.

scholarly journals First Type III Solar Radio Bursts of Solar Cycle 25

Solar Physics ◽  
2021 ◽  
Vol 296 (4) ◽  
Author(s):  
Juha Kallunki ◽  
Derek McKay ◽  
Merja Tornikoski
Keyword(s):  
Solar Cycle ◽  
Solar Radio ◽  
Low Frequency ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Type Iii ◽  
Receiver Array ◽  
Imaging Receiver ◽  
Solar Bursts ◽  
Cycle 24

AbstractThe minimum of the previous solar cycle, Solar Cycle 24, occurred in December 2019, which also marked the start of the new Solar Cycle 25. The first radio bursts of the new solar cycle were observed in the spring season 2020. In this work we will present three type III solar bursts which were observed in May and June 2020 at radio frequencies between 18 – 90 MHz. There are two radio observatories in Finland that are capable of doing low-frequency solar radio observations: Aalto University Metsähovi Radio Observatory (MRO) and Kilpisjärvi Atmospheric Imaging Receiver Array (KAIRA) of the Sodankylä Geophysical Observatory, University of Oulu. The instruments of the two institutes have different design and characteristics, and they operate in rather different radio interference environments. We will compare simultaneous observations from these two instruments and we will also discuss the properties of these type III solar bursts.

scholarly journals High Resolution Studies of Type III Solar Radio Bursts

1974 ◽  
Vol 57 ◽  
pp. 225-226
Author(s):  
C. Chiuderi ◽  
R. Giachetti ◽  
C. Mercier ◽  
H. Rosenberg ◽  
C. Slottje
Keyword(s):  
Solar Radio ◽  
Plasma Frequency ◽  
Solar Radius ◽  
Average Height ◽  
Radio Bursts ◽  
General Shape ◽  
Solar Radio Bursts ◽  
Type Iii ◽  
Temporal And Spatial ◽  
East West

(Solar Phys.). High spectral, temporal and spatial resolution observations were obtained with the 60-channel Utrecht solar radio spectrograph (160–320 MHz) and the 169 MHz Nançay solar radioheliograph. From a large number of type III bursts the average height was found to be 0.37 solar radius above the photosphere, corresponding to approximately the Newkirk streamer density, if the bursts are emitted at the harmonic of the local plasma frequency. No center-to-limb variation, nor east-west asymmetry was observed. All double bursts, double humped bursts, precursor-type III had exactly the same position and general shape for both members of the pair. From this it was concluded that fundamental-harmonic pairs are very rare at frequencies above 160 MHz (Mercier and Rosenberg, 1974).

On the Fundamental and Harmonic Components of Low-Frequency Type III Solar Radio Bursts

1982 ◽  
Vol 4 (4) ◽  
pp. 382-386 ◽  
Author(s):  
S. Suzuki ◽  
K.V. Sheridan
Keyword(s):  
Solar Radio ◽  
Plasma Frequency ◽  
Low Frequency ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Type Iii ◽  
Field Lines ◽  
Harmonic Components ◽  
Electro Magnetic ◽  
Open Magnetic Field

Ground-based observations of Type III bursts made with spectrographs and spectro-polarimeters, at frequencies above the ionospheric cut-off, reveal that most bursts (excluding storm Type IIIs) have fundamental (F) and harmonic (H) structure (Wild et al. 1959; Dulk and Suzuki 1980). An example of F-H bursts is given by Sheridan (1978). Such bursts are produced by streams of electrons travelling along open magnetic field lines and exciting plasma oscillations which are converted to electro-magnetic waves at both the F and H frequencies of the local plasma frequency in the corona.

scholarly journals Meter and Decameter Wavelength Positions of Solar Radio Bursts of July 31–August 7, 1972

1974 ◽  
Vol 57 ◽  
pp. 231-233
Author(s):  
M. R. Kundu ◽  
W. C. Erickson
Keyword(s):  
Solar Phys ◽  
Solar Radio ◽  
Base Line ◽  
Radio Bursts ◽  
Frequency Range ◽  
Solar Radio Bursts ◽  
Spiral Antennas ◽  
Positional Analysis ◽  
Decameter Wavelength ◽  
Solar Bursts

(Solar Phys.). The positional analysis of solar bursts at meter and decameter wavelengths during the period July 31–August 7, 1972 is presented. The observations were taken with two arrays – a log periodic array of 16 elements situated on an E–W base line of 3.3 km and portions of the new Clark Lake array in the form of a Tee (an E–W arm of 32 log spiral antennas and a N–S arm of 16 similar antennas). The new array operates over the frequency range 10–120 MHz and has angular resolutions of approximately 3.′5 at 100 MHz and 8.′5 at 40 MHz in the E–W direction.

Sign in / Sign up

Export Citation Format

Share Document