Solar type IV burst spectral fine structures

Zlotnik, E. Ya.; Зайцев, В. В.; Auraß, H.; Mann, G.; Hofmann, Axel

doi:10.1051/0004-6361:20031250

Cited by 80 publications

(80 citation statements)

References 38 publications

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“…Fiber bursts are explained by completely different mechanism, the interaction of plasma waves with whistlers, propagating with the group velocity in the form of the periodic wave packets. The DPR-mechanism obtained wide recognition due to the most detailed developments of Zheleznyakov (1995) and subsequent series of articles and reviews of Zlotnik (Zlotnik et al (2003). Zlotnik (2009), Zlotnik, (2010).…”

Section: Discussionmentioning

confidence: 99%

“…The DPR-mechanism obtained wide recognition due to the most detailed developments of Zheleznyakov (1995) and subsequent series of articles and reviews of Zlotnik (Zlotnik et al (2003). Zlotnik (2009), Zlotnik, (2010). …”

Section: Discussionmentioning

confidence: 99%

“…In the critical review of Zlotnik (2009), the advantages of the DPR model and the main failures of the model with whistlers are refined. The author asserts that the theory based on the DPR effect is the best-developed theory for ZP origin at meter-decimeter wavelengths at the present time.…”

Section: Discussionmentioning

confidence: 99%

“…and gives a good fit for the observed radio spectrum peculiarities with quite reasonable parameters of the radiating electrons and coronal plasma. The statement that the theory based on whistlers is able to explain only a single stripe (e.g., a fiber burst) was made in Zlotnik (2009) without the correct ideas of whistler excitation and propagation in the solar corona.…”

Section: Discussionmentioning

confidence: 99%

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Dynamics of Flare Processes and Variety of the Fine Structure of Solar Radio Emission over a Wide Frequency Range of 30 – 7000 MHz

et al. 2014

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Radiobursts exibiting fine structure observed over two years during the rising phase of Cycle 24 by the Chinese Solar Broadband Radio Spectrometer (SBRS/Huairou) in the range 1-7.6 GHz and the spectrograph IZMIRAN in the meter range (25 -270 MHz) are analyzed. In five events zebra structure, various fiber bursts and fast pulsations were observed. These observations have great importance for testing different theoretical models of fine structure formation, as, for example, only for explaining the zebra-structure more than ten mechanisms have been proposed. Events on 15 and 24 February 2011 are of the greatest interest. In the course of the flare on 15 February (which occurred close to the center of disk) zebra structure was observed during three sequential flare brightenings. The polarization changed sign in the third. This behavior of polarization combined with images of the corresponding flare brightenings, obtained in extreme ultraviolet radiation by the Solar Dynamics Observatory (SDO/AIA, 171 Å) provides important clues. The polarization of radio emission in all three cases is related to the ordinary wave mode of radio emission. The zebra structure was present at frequencies 190-220 MHz in the Culgoora spectrum. The event on 24 February 2011 is remarkable, as the zebra structure at frequencies of 2.6-3.8 GHz was not polarized and it appeared during the magnetic reconnection observed by SDO/AIA 171 Å in this limb flare. In the event on 9 August 2011, for the first time, a superfine millisecond structure was registered simultaneously in the fast pulsations and the stripes of zebra structure. In the event on 1 August 2010 after the zebra structure two families of fibers bursts with an opposite frequency drift were observed. On 19 April 2012 the fibers against the background of type III bursts were observed by IZMIRAN and Nançay spectrographs. In the band of 42 -52 MHz a group of nine slowly drifting narrow-band (

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Dynamics of Flare Processes and Variety of the Fine Structure of Solar Radio Emission over a Wide Frequency Range of 30 – 7000 MHz

et al. 2014

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“…They occur as a consequence of secondary processes in the continuum source volume, e.g. loop collisions (Khan & Aurass 2006), whistler wave propagation (Benz & Mann 1998), double-plasma-resonance of bouncing electrons (Zlotnik et al 2003), or simply injection of a new electron ensemble ).…”

Section: Introductionmentioning

confidence: 99%

A microflare with hard X-ray-correlated gyroresonance line emission at 314 MHz

Auraß

Rausche

Berkebile-Stoiser

et al. 2010

A&A

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Context. Small energy release events in the solar corona can give insights into the flare process which are regularly hidden in the complex morphology of larger events. For one case we find a narrowband radio signal well correlated with the hard X-ray flare. We investigate wether these signals are probes for the flare current sheet. Aims. We aim to establish the relation between narrowband and short-duration features (<1% of the observing frequency in the spectral range 250-340 MHz, and some 5 s until 2 min, respectively) in dynamic radio spectral diagrams and simultaneously occuring HXR bursts. Methods. We use dynamic radio spectra from the Astrophysical Institute Potsdam, HXR images of RHESSI, TRACE coronal and chromospheric images, SOHO-MDI high resolution magnetogram data, and its potential field extrapolation for the analysis of one small flare event in AR10465 on September 26, 2003. We point to similar effects in e.g. the X-class flare on November 03, 2003 to demonstrate that we are not dealing with a singular phenomenon. Results. We confirm the solar origin of the extremely narrowband radio emission. From RHESSI images and the magnetic field data we identify the probable site of the radio source as well as the HXR footpoint and the SXR flare loop emission. The flare loop is included in an ongoing change of magnetic connectivity as confirmed by TRACE images of hot coronal loops. The flare energy is stored in the nonpotential magnetic field substructure around the microflare site which is relaxed to a potential one. Conclusions. We conclude that the correlated HXR footpoint/narrowband radio emission, and the transition to a second energy release in HXR without associated radio emission are direct probes of changing magnetic connectivity during the flare. We suppose that the narrowband radio emission is due to gyroresonance radiation at the second harmonic of the local electron cyclotron frequency. It follows an upper limit of the magnetic field in the radio source volume of less than 50% of the mean potential field in the same height range. This supports the idea that the narrowband radio source is situated in the immediate surroundings of the flare current sheet.

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Interpretation of the zebra pattern in the Jovian kilometric radiation

2016

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The origin of a fine structure as quasi‐harmonic parallel drifting stripes of enhanced brightness (zebra pattern) in the dynamic spectrum of Jovian kilometric radiation is discussed. A possible interpretation of the observed structure based on the effect of double plasma resonance (DPR) in the Jupiter magnetosphere is analyzed. It is shown that the observed features of the zebra pattern cannot be attributed to the DPR effect at electron cyclotron harmonics. The proposed scheme consists of excitation of ion cyclotron waves at the low hybrid frequency in the ion DPR regions and succeeding coalescence of these waves with a longitudinal wave at the upper hybrid frequency. The source parameters necessary for matching the expected and observed properties of the Jupiter zebra pattern are discussed.

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Solar type IV burst spectral fine structures

Cited by 80 publications

References 38 publications

Dynamics of Flare Processes and Variety of the Fine Structure of Solar Radio Emission over a Wide Frequency Range of 30 – 7000 MHz

Dynamics of Flare Processes and Variety of the Fine Structure of Solar Radio Emission over a Wide Frequency Range of 30 – 7000 MHz

A microflare with hard X-ray-correlated gyroresonance line emission at 314 MHz

Interpretation of the zebra pattern in the Jovian kilometric radiation

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