On the Relative Position and Origin of Harmonics in the Spectra of Solar Radio Bursts of Spectral Types II And III

Smerd, S. F.; Wild, J. P.; Sheridan, K. V.

doi:10.1071/ph620180

Cited by 79 publications

(31 citation statements)

References 8 publications

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“…It should be mentioned, however, that the variation of position with frequency for second harmonic bands is les8 than for fundamental bands, and that the positions for second harmonic bands tend to lie irMide the positions for fundamental bands. These results are consistent with the conclusion of Smerd, Wild, and Sheridan (1962) that in those few cases where a definite decision could be made, the position for the second harmonic band of a type II burst invariably lay inside the position for the fundamental band· of the same burst.…”

Section: (B) Anomalous P08itions Of Source8 Of Harmonic Bandssupporting

confidence: 81%

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The Positions and Movements of the Sources of Solar Radio Bursts of Spectral Type II

Weiß¹

1963

Aust. J. Phys.

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SummaryThe east-west position coordinates of the sources of 22 type II radio bursts, measured in the range 40-70 Mc/s using a swept-frequency interferometer, are analysed and discussed, in conjunction with dynamic spectra obtained in the frequency range 15-210 Mc/s. Many bursts are multiple and consist of a number of separate bursts excited by disturbances ejected in different directions from the vicinity of an optical flare, which may be equally complex.A statistical analysis of position data for type II and type III bursts, which reveals a remarkable similarity in the general behaviour of the two types of bursts, confirms the hypothesis of generation of the radio emissions by plasma oscillations. Other topics discussed are the relative intensities of fundamental and second harmonic bands of the same burst, the relative positions of the sources of fundamental and second harmonic bands of identical frequency, and the relative positions of the sources of the two ridges of a split band.Many type II bursts exhibit temporal changes of position at a single frequency. These are indicative of tangential movements in the solar atmosphere, with speeds of the order of 1000-2000 km/s. The spectra of these bursts with movement on the disk are characterized by little or no drift of frequency with time, and by broad bandwidth.A mean radial distribution of electron density in the disturbed corona is derived. This distribution does not differ greatly from that found optically for the average coronal streamer.

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Section: (B) Anomalous P08itions Of Source8 Of Harmonic Bandssupporting

confidence: 81%

“…This ourious result appears to be inoonsistent with the plasma hypothesis. An explanation involving propagation effeots has been proposed by Smerd, Wild, and Sheridan (1962).…”

Section: (Vi) Relative Positions Of the Sources Of Fundamental And Sementioning

confidence: 99%

The Positions and Movements of the Sources of Solar Radio Bursts of Spectral Type II

Weiß¹

1963

Aust. J. Phys.

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“…The type II source position (Figure 3 b) shows the characteristic dispersion in frequency: however, it moves to a lower position toward the end of the burst (around 1754 UT). If the harmonic is present, then the lower position at later times at the same frequency is quite consistent with the interpretation that the harmonic is due to combination scattering (Smerd et al, 1962). In the absence of a harmonic, one has to interpret this movement as tangential to the surfaces of constant electron density (Weiss, 1963).…”

Section: Type III and Type V Burstssupporting

confidence: 63%

A new wideband, fully steerable, decametric array at Clark Lake

Erickson

Fisher

1974

Radio Science

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A new, fully steerable, decametric array for radio astronomy is under construction at the Clark Lake Radio Observatory near Borrego Springs, California. This array will be a “T” of 720 conical spiral antennas (teepee‐shaped antennas, hence the array is called the TPT), 3.0 by 1.8 km capable of operating between 15 and 125 MHz. Both its operating frequency and beam position will be adjustable in less than one msec, and the TPT will provide a 49‐element picture around the central beam position for extended‐source observations. Considerable experience has been gained in the operation of completed portions of the array, and successful operation of the final array is assured. This paper describes the results of the tests which have been conducted with the conical spirals and outlines the planned electronics.

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“…Observations find that waves of the fundamental (F) component and the second harmonic (H) component of type III bursts with same frequency have coincidental source regions. This finding is reported and discussed in a number of publications (Smerd et al 1962;Bougeret et al 1970;McLean 1971;Stewart 1972Stewart , 1974aStewart , 1974bDulk & Suzuki 1980). It implies that the nature of the F waves and H waves, as well as the observed source regions, deserves more study.…”

Section: Introductionmentioning

confidence: 80%

Altitude‐dependent Emission of Type III Solar Radio Bursts

Wang

Zhou

et al. 2005

ApJ

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The present discussion complements a preceding article in which a cyclotron-maser theory of type III solar radio bursts is proposed. One important issue, which has not been addressed in any of the existing theories, is that in the event of a F-H pair emission dynamic spectra usually show an initial time delay of the fundamental (F) component after the harmonic (H) component has commenced. Moreover, the ratio of the starting frequencies of the H waves to those of the F waves is generally higher than 2. A plausible interpretation is that the emission of H waves starts at an altitude lower than that for F waves. This notion leads to the present study. Although it is formulated within the context of the cyclotron-maser scenario, the model of the source electrons is different from that discussed previously.

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On the Relative Position and Origin of Harmonics in the Spectra of Solar Radio Bursts of Spectral Types II And III

Cited by 79 publications

References 8 publications

The Positions and Movements of the Sources of Solar Radio Bursts of Spectral Type II

The Positions and Movements of the Sources of Solar Radio Bursts of Spectral Type II

A new wideband, fully steerable, decametric array at Clark Lake

Altitude‐dependent Emission of Type III Solar Radio Bursts

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