Position and Polarization of Solar Drift Pair Bursts

Suzuki, S.; Gary, Dale E.

doi:10.1017/s1323358000026151

Cited by 14 publications

(19 citation statements)

References 4 publications

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“…By the way, this feature was accompanied by weak solar activity. All this is consistent with the results of Suzuki and Gary (1979) obtained at a higher frequency. To provide the angular selection of DP component sources in this frequency range, we are going to perform special interferometer measurements in prospect.…”

Section: B) Drift Pair Burstssupporting

confidence: 93%

“…The current state of spectral research of DPs is presented in the recent paper of Stanislavsky et al (2017). However, as for the mapping of DP sources, one can mention only the long-standing paper of Suzuki and Gary (1979). The radio imaging of DPs were carried out at a single frequency (at 43 MHz), and new heliographic observations are very relevant.…”

Section: Datamentioning

confidence: 99%

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An upgrade of the UTR-2 radio telescope to a multifrequency radio heliograph

Stanislavsky¹,

Konovalenko²,

Koval³

et al. 2018

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We present the broadband heliograph based on the UTR-2 radio telescope for obtaining the solar corona images in the frequency range 8-32 MHz with the frequency resolution 4 kHz, the time resolution up to 1 ms, and under the dynamic range about 90 dB. The instrument provides new possibilities to measure the non-thermal radiation in an unprecedented way for a better understanding of the radio emission processes in solar corona. We describe various aspects of the instrument including its antenna system, receiver front end, digital hardware and the data acquisition. This is the lowest-frequency heliograph operating in the world. It allows us to detect radio emission from solar radio sources in the upper solar corona near frequencies of ionosphere cut-off. The instrument performance is illustrated with source maps of solar radio bursts at low frequencies during the observational campaigns of 2013 and 2015.

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Section: B) Drift Pair Burstssupporting

confidence: 93%

Section: Datamentioning

confidence: 99%

An upgrade of the UTR-2 radio telescope to a multifrequency radio heliograph

Stanislavsky¹,

Konovalenko²,

Koval³

et al. 2018

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“…But in this case, the second component, as was correctly noted by Riddle (1974), is to be both decreased in intensity and smoothed, which is not confirmed by observations. Besides that, the heliographic observations (Suzuki and Gary, 1979) show that the place of generation of both components is practically the same. Melrose (1982) proposed the model, in which DPs components are formed because of reflections from duct walls.…”

Section: Discussionmentioning

confidence: 73%

“…Another property of DPs is constant time delay of the second element which equals 1-2 s at all frequencies. Suzuki and Gary (1979) noted that both DP elements had the same sense of polarization but their degree of polarization was different. They also provided the results of radioheliograph data, which showed that source positions were the same for both DP elements and coincided with the Type III source position.…”

Section: Introductionmentioning

confidence: 99%

Solar Drift Pair Bursts in the Decameter Range

et al. 2005

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The results of observations of solar decametric drift pair bursts are presented. These observations were carried out during a Type III burst storm on July 11-21, 2002, with the decameter radio telescope UTR-2, equipped with new back-end facilities. High time and frequency resolution of the back-end allowed us to obtain new information about the structure and properties of these bursts. The statistical analysis of more than 700 bursts observed on 13-15 July was performed separately for "forward" and "reverse" drift pair bursts. Such an extensive amount of these kind of bursts has never been processed before. It should be pointed out that "forward" and "reverse" drift pair bursts have a set of similar parameters, such as time delay between the burst elements, duration of an element, and instant bandwidth of an element. Nevertheless some of their parameters are different. So, the absolute average value of frequency drift rate for "forward" bursts is 0.8 MHz s −1 , while for "reverse" ones it is 2 MHz s −1 . The obtained functional dependencies "drift rate vs. frequency" and "flux density vs. frequency" were found to be different from the current knowledge. We also report about the observation of unusual variants of drift pairs, in particular, of "hook" bursts and bursts with fine time and frequency structure. A possible mechanism of drift pairs generation is proposed, according to which this emission may originate from the interaction of Langmuir waves with the magnetosonic waves having equal phase and group velocities.

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“…The most enigmatic characteristic of DPBs is that in contrast to other multi-stripe bursts (e.g., type II bursts and zebra patterns), their components are shifted in time rather than in frequency -the second component of a pair looks like a repetition of the first one (although sometimes with a slightly different intensity), while the frequency shift is absent or very small (Ellis 1969;de La Noe & Moller Pedersen 1971;Moller-Pedersen et al 1978;Melrose 1982;Melnik et al 2005). The polarization degree varies from very low to ∼ 50%; the higher-frequency component (i.e., the first component of the pairs with positive frequency drift and the second component of the pairs with negative frequency drift) generally has a higher polarization degree (Suzuki & Gary 1979;Dulk et al 1984). Sometimes, unusual variations of DPBs are observed, such as the so-called hooks and structures with a third component (Ellis 1969;Melnik et al 2005).…”

Section: Introductionmentioning

confidence: 99%

First imaging spectroscopy observations of solar drift pair bursts

Kuznetsov

Kontar

2019

A&A

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Drift pairs are an unusual and puzzling type of fine structure sometimes observed in dynamic spectra of solar radio emission. They appear as two identical short narrowband drifting stripes separated in time; both positive and negative frequency drifts are observed. Currently, due to the lack of imaging observations, there is no satisfactory explanation for this phenomenon. Using the Low Frequency Array (LOFAR), we report unique observations of a cluster of drift pair bursts in the frequency range of 30 − 70 MHz made on 12 July 2017. Spectral imaging capabilities of the instrument have allowed us for the first time to resolve the temporal and frequency evolution of the source locations and sizes at a fixed frequency and along the drifting pair components. Sources of two components of a drift pair have been imaged and found to propagate in the same direction along nearly the same trajectories. Motion of the second component source is seen to be delayed in time with respect to that of the first one. The source trajectories can be complicated and non-radial; positive and negative frequency drifts correspond to opposite propagation directions. The drift pair bursts with positive and negative frequency drifts, as well as the associated broadband type-III-like bursts, are produced in the same regions. The visible source velocities are variable from zero to a few 10 4 (up to ∼ 10 5 ) km s −1 , which often exceeds the velocities inferred from the drift rate (∼ 10 4 km s −1 ). The visible source sizes are of about 10 ′ − 18 ′ ; they are more compact than typical type III sources at the same frequencies. The existing models of drift pair bursts cannot adequately explain the observed features. We discuss the key issues that need to be addressed, and in particular the anisotropic scattering of the radio waves. The broadband bursts observed simultaneously with the drift pairs differ in some aspects from common type III bursts and may represent a separate type of emission.

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Position and Polarization of Solar Drift Pair Bursts

Cited by 14 publications

References 4 publications

An upgrade of the UTR-2 radio telescope to a multifrequency radio heliograph

An upgrade of the UTR-2 radio telescope to a multifrequency radio heliograph

Solar Drift Pair Bursts in the Decameter Range

First imaging spectroscopy observations of solar drift pair bursts

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