Flare-time sudden enhancements of low frequency field strength and associated meter wave solar radio bursts

Solar Physics ◽  
1969 ◽  
Vol 9 (1) ◽  
pp. 198-204 ◽  
Author(s):  
S. K. Alurkar ◽  
R. V. Bhonsle
Keyword(s):  
Field Strength ◽  
Solar Radio ◽  
Low Frequency ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Frequency Field

scholarly journals Low Frequency Radio Astronomy from Above the Ionosphere

2002 ◽  
Vol 199 ◽  
pp. 488-489
Author(s):  
D. L. Jones
Keyword(s):  
High Resolution ◽  
Radio Astronomy ◽  
Coronal Mass Ejections ◽  
Solar Radio ◽  
Low Frequency ◽  
Dramatic Improvement ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Low Frequencies ◽  
High Resolution Images

The GMRT represents a dramatic improvement in ground-based observing capabilities for low frequency radio astronomy. At sufficiently low frequencies, however, no ground-based facility will be able to produce high resolution images while looking through the ionosphere. A space-based array will be needed to explore the objects and processes which dominate the sky at the lowest radio frequencies. An imaging radio interferometer based on a large number of small, inexpensive satellites would be able to track solar radio bursts associated with coronal mass ejections out to the distance of Earth, determine the frequency and duration of early epochs of nonthermal activity in galaxies, and provide unique information about the interstellar medium.

scholarly journals Characterization of Selected Solar Radio Bursts Based on Solar Activity Detected by e-CALLISTO (Malaysia)

2014 ◽  
Vol 32 ◽  
pp. 144-154
Author(s):  
Zety Sharizat Hamidi ◽  
N.N.M. Shariff ◽  
C. Monstein
Keyword(s):  
Solar Flare ◽  
Coronal Mass Ejections ◽  
Solar Radio ◽  
Low Frequency ◽  
Weather Condition ◽  
Impulsive Phase ◽  
Primary Energy ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Solar Burst

One of the main reasons to study more about the dynamics of solar radio bursts is because solar these bursts can interfere with the Global Positioning System (GPS) and communications systems. More importantly, these bursts are a key to understand the space weather condition. Recent work on the interpretation of the low frequency region of a main solar burst is discussed. Continuum radio bursts are often related to the solar activities such as an indication of the formation of sunspot, impulsive phase of solar flares and Coronal Mass Ejections (CMEs) and their frequencies correspond to the densities supposed to exist in the primary energy release volume. Specifically, solar burst in low frequency play an important role in interpretation of Sun activities. In this work, we have selected few solar bursts that successfully detected by our station at the National Space Centre, Banting Selangor. Our objective is to correlate the solar burst with Sun activities by looking at the main sources that responsibility with the trigger of solar burst. It is found that type II burst is dominant with Coronal Mass Ejections (CMEs), type III burst associated with solar flare, IV burst with the formation of active region and type U burst high solar flare. We believed that this work is a good start to monitor Sun’s activities in Malaysia as equatorial country.

On Low‐Frequency Type III Solar Radio Bursts Observed in Interplanetary Space

2004 ◽  
Vol 605 (1) ◽  
pp. 503-510 ◽  
Author(s):  
C. S. Wu ◽  
M. J. Reiner ◽  
P. H. Yoon ◽  
H. N. Zheng ◽  
S. Wang
Keyword(s):  
Solar Radio ◽  
Interplanetary Space ◽  
Low Frequency ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Type Iii

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.

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.

Low frequency spectra of type III solar radio bursts

Solar Physics ◽  
1978 ◽  
Vol 59 (2) ◽  
pp. 377-385 ◽  
Author(s):  
Richard R. Weber
Keyword(s):  
Solar Radio ◽  
Low Frequency ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Frequency Spectra ◽  
Type Iii

Sizes of solar radio sources observed by LOFAR

2021 ◽  
Author(s):  
Mykola Gordovskyy ◽  
Eduard Kontar ◽  
Daniel Clarkson ◽  
Philippa Browning
Keyword(s):  
Solar Corona ◽  
Radio Wave ◽  
Solar Radio ◽  
Low Frequency ◽  
Theoretical Models ◽  
High Energy ◽  
Emission Sources ◽  
Radio Sources ◽  
Radio Bursts ◽  
Solar Radio Bursts

<p>Decametric radio emission provides a unique insight into the physics of solar and heliospheric plasmas. Along with dynamic spectra, the spatial characteristics of the emission sources observed in solar radio bursts yield important information about the behaviour of high-energy non-thermal electrons, and the state of thermal plasma in the upper solar corona. Recently, it has been shown that sizes and locations of radio sources in the 10-100 MHz range can be used as a diagnostic tool for plasma turbulence in the upper corona and inner heliosphere. However, observations in this spectral range can be strongly affected by limited spatial resolution of the instrument, as well as by the effect of the Earth's ionosphere on radio wave propagation.</p><p>We describe a new method for correcting radio intensity maps for instrumental and ionospheric effects using observations of a known radio source at an arbitrary location in the sky. Based on this method, we derive sizes and areas of the emission sources in the solar radio bursts observed by the Low-Frequency Array (LOFAR) in 30-45 MHz range. It is shown that the sizes of sources are of the order of ten arcminutes and decrease with increasing frequency. Overall, we find that the sizes and their variation, as well as the shapes of the sources in the considered events are consistent with the theoretical models of turbulent radio-wave scattering in the solar corona  developed by Kontar et al. 2019 (Astrophys.J., 884, 122).</p>

Exploring the circular polarisation of low-frequency solar radio bursts with LOFAR and estimating the coronal magnetic field

2021 ◽  
Author(s):  
Diana Morosan ◽  
Anshu Kumari ◽  
Juska Räsänen ◽  
Emilia Kilpua ◽  
Pietro Zucca ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Radio ◽  
Low Frequency ◽  
Coronal Magnetic Field ◽  
Plasma Emission ◽  
The Sun ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Circular Polarisation ◽  
Type Iii

<p>The Sun is an active star that often produces numerous bursts of electromagnetic radiation at radio wavelengths. In particular, low frequency (< 150 MHz)  radio bursts have recently been brought back to light with the advancement of novel radio interferometric arrays. However, the polarisation properties of solar radio bursts have not yet been explored in detail, especially with the Low Frequency Array (LOFAR). Here, we explore the circular polarisation of type III radio bursts and a type I noise storm and present the first Stokes V low frequency radio images of the Sun with LOFAR in tied array mode observations. We find that the degree of circular polarisation for each of the selected bursts increases with frequency for fundamental plasma emission, while this trend is either not clear or absent for harmonic plasma emission. In the case of type III bursts, we also find that the sense of circular polarisation varies with each burst, most likely due to their different propagation directions, despite all of these bursts being part of a long-lasting type III storm. Furthermore, we use the degree of circular polarisation of the harmonic emission of type III bursts to estimate the coronal magnetic field at distances of 1.4 to 4 solar radii from the centre of the Sun. We found that the magnetic field has a power law variation with a power index in the range 2.4-3.6, depending on the individual type III burst observed.</p>

scholarly journals Fine Structure in Type IV Solar Radio Bursts

1974 ◽  
Vol 57 ◽  
pp. 291-292
Author(s):  
C. Caroubalos ◽  
M. Pick ◽  
C. Chiuderi ◽  
R. Giachetti ◽  
H. Rosenberg ◽  
...  
Keyword(s):  
Fine Structure ◽  
High Frequency ◽  
Solar Radio ◽  
Low Frequency ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Type Iv ◽  
Low Frequency Oscillations ◽  
Solar Type ◽  
Frequency Radiation

(Solar Phys.). The fine structure in solar type IV radio bursts was studied using the 169 MHz Nançay radioheliograph and the 60 channel radiospectrograph at Utrecht (160–320 MHz). The observed fine structure includes pulsating structure, zebra patterns (parallel drifting bands) and intermediate drift bursts. All are considered as modulation of high frequency radiation by low frequency oscillations or as the result of up conversion of low frequency oscillations to higher frequencies (Rosenberg, 1973).

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