An Association Between Solar Radio Bursts at Metre and Centimetre Wavelengths

Neylan, AA

doi:10.1071/ph590399

Cited by 18 publications

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“…The existence of temporal correlations between coherent and incoherent flare radio emissions has been known since earlier studies (e.g. Neylan, 1959), where type III bursts were found to be generally accompanied by enhanced microwave and hard X-ray flux. Assuming that both types of emission are induced by the same population of accelerated electrons, analysis of the time delays between them allows, in particular, for detecting the direction of the electron beam propagation and estimating its speed.…”

Section: Introductionmentioning

confidence: 91%

Common Origin of Quasi-Periodic Pulsations in Microwave and Decimetric Solar Radio Bursts

et al. 2021

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Section: Introductionmentioning

confidence: 91%

Common Origin of Quasi-Periodic Pulsations in Microwave and Decimetric Solar Radio Bursts

et al. 2021

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Section: Correlation Of Type Iii-v Bursts and Hard X-ray Burstsmentioning

confidence: 99%

“…This is the first time, to the author's knowledge, that convincing evidence for a close association between type III-V bursts and hard X-ray bursts has been presented. The relationship between type V bursts and microwave bursts has been known for some time (Neylan, 1959).A typical example of a hard X-ray associated type III-V burst is shown in Figure 1. In this event, and also in at least 50% of the events in Table I, the type V burst is followed within 5 rain by a type II burst.…”

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confidence: 99%

Relationship between type III-V radio and hard X-ray bursts

Stewart

1978

Sol Phys

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Type III-V radio bursts are found to be closely associated with impulsive hard X-ray bursts.Probably 0.1% to 1% of the fast electrons in the X-ray source region escape to heights >0.1Ro in the corona and excite the type III-V burst. Correlation of Type III-V Bursts and Hard X-Ray BurstsKane (1972) has argued for a common origin of the non-thermal electrons responsible for impulsive hard X-ray and type III bursts on the grounds that he finds a good correlation between the times of maxima of the two bursts. He reported that 32% of impulsive X-ray events are associated with type III bursts. A close look at the eight Culgoora radio spectrograph events in Kane's list shows that five of these events are actually intense type III-V bursts where the type III burst or group is followed by broadband type V radiation of duration -1 min. Similarly, all three Culgoora events in Lin and Hudson's (1971) and Kane and Lin's (1972) lists are type III-V bursts. In addition, all five of the metre-wavelength bursts associated with single-spike hard X-ray bursts studied by Crannell et al. (1977) contain type III-V bursts.To obtain better statistics the author has checked the Culgoora spectral records during all reported impulsive hard X-ray bursts find has found that in 80% of the cases where there are associated radio events the event was a type IIl group containing a type V burst. Unfortunately there was insufficient data available to say what percentage of type III-V bursts occurred without hard X-ray bursts. Altogether some 30 type III-V bursts were found to be associated with hard X-ray and microwave events. These are listed in Table I. We see that the times of maxima of the three different impulsive bursts usually agree to within <20 s and that the starting and ending times are also similar. This is the first time, to the author's knowledge, that convincing evidence for a close association between type III-V bursts and hard X-ray bursts has been presented. The relationship between type V bursts and microwave bursts has been known for some time (Neylan, 1959).A typical example of a hard X-ray associated type III-V burst is shown in Figure 1. In this event, and also in at least 50% of the events in Table I, the type V burst is followed within 5 rain by a type II burst. Usually the X-ray and microwave impulsive bursts contain more than one but fewer than 10 spikes of duration < 10 s, suggesting that several pulses of fast electrons are injected into the source regions near the base of the corona. It is not clear whether each X-ray spike is associated Solar Physics 58 (1978) 121-126. All Rights Reserved Copyright 9 1978 by D. Reidel Publishing Company, Dordrecht, Holland

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“…In the past, comparison was made on the basis of single-frequency observations between bursts on centimeter and meter waves, and it was noted that there is a close association between the bursts of great intensity. For example, it was observed [Kundu, 1959;Avignon and Pick, 1959] that a type IV burst on meter waves is generally associated with an intense centimeterwave burst lasting for more than 10 minutes; also Neylan [1959] has found a close association between meter-wave type V bursts and certain centimeter-wave bursts. However, no systematic studies have been made of the association between different spectral types of meter-and centimeter-wave bursts.…”

Section: Introductionmentioning

confidence: 99%

Association of centimeter-wave bursts with different spectral types of meter-wave bursts of solar radio emission

Kundu¹

1962

J. Geophys. Res.

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It is shown that about 40 per cent of 10.7 cm‐λ bursts with peak intensities greater than 5×10−22 wm−2 (c/s)−1 are accompanied by bursts on meter waves. The percentage association increases with the peak intensity of 10.7 cm‐λ bursts and attains a value of about 90 per cent when the peak intensity exceeds 1000×10−22 wm−2 (c/s)−1. The reverse association, that is, the association of a meter‐λ burst with a burst on centimeter waves, is dependent on the spectral type of the meter‐λ burst. The association is about 15, 40, 70, and 100 per cent for types III, V, II, and IV, respectively. The type III and type V bursts usually occur within about 1 minute and ½ minute, respectively, of the associated cm‐λ burst maxima. The type II bursts occur after about 2 to 6 minutes of the associated cm‐λ burst maxima. The type IV bursts in the 250 to 580 Mc/s range occur within about 4 minutes of the start of the associated cm‐λ bursts. From simultaneous dynamic spectral observations in the 25 to 580 Mc/s range and single‐frequency observations on 9400, 3750, 2000, and 1000 Mc/s, the average spectra of cm‐λ bursts associated with different spectral types of meter‐λ bursts have been studied. It is shown that cm‐λ bursts associated with meter‐λ type IV and type II bursts have brightness temperatures of the order of 108 and 107 deg K, respectively, and can probably be explained by synchrotron radiation of high‐energy electrons. The cm‐λ bursts associated with type V and type III bursts have brightness temperatures of 106 to 107 deg K in the 2000 to 9400 Mc/s range and have probably a thermal plus synchrotron origin; the 1000 Mc/s bursts have brightness temperatures higher than 107 deg K and have a nonthermal origin, probably due to plasma oscillation corresponding to type III bursts. The cm‐λ bursts unaccompanied by any meter‐λ burst have brightness temperatures less than 106 deg K and are believed to have a thermal origin.

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An Association Between Solar Radio Bursts at Metre and Centimetre Wavelengths

Cited by 18 publications

References 0 publications

Common Origin of Quasi-Periodic Pulsations in Microwave and Decimetric Solar Radio Bursts

Common Origin of Quasi-Periodic Pulsations in Microwave and Decimetric Solar Radio Bursts

Relationship between type III-V radio and hard X-ray bursts

Association of centimeter-wave bursts with different spectral types of meter-wave bursts of solar radio emission

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