Cyclotron wave instability in the corona and origin of solar radio emission with fine structure

Zheleznyakov, V. V.; Zlotnik, E. Ya.

doi:10.1007/bf00153225

Cited by 142 publications

(96 citation statements)

References 6 publications

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“…In agreement with Zheleznyakov & Zlotnik (1975), we assume that the distance l d can be computed from the formula…”

Section: Determining the Plasma Parametersmentioning

confidence: 99%

“…Many models explaining zebras have been proposed (Rosenberg 1972;Kuijpers 1975;Zheleznyakov & Zlotnik 1975;Chernov 1976Chernov , 1990LaBelle et al 2003;Kuznetsov & Tsap 2007;Bárta & Karlický 2006;Ledenev et al 2006;Laptukhov & Chernov 2009;Tan 2010;Karlický 2013). But most of them do not explain all observed features of zebras: the frequency range, bandwidth, polarization, number and frequency separation of zebra lines, their time variations and the high-frequency limit.…”

Section: Introductionmentioning

confidence: 99%

“…Among all proposed mechanisms, the most promising one is that based on the double plasma resonance (DPR; Zheleznyakov & Zlotnik 1975;Zlotnik 2013). This model assumes that the zebra line emission is generated at locations where the upperhybrid frequency f up equals multiples of the electron-cyclotron frequency f b .…”

Section: Introductionmentioning

confidence: 99%

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Determination of plasma parameters in solar zebra radio sources

Karlický

Yasnov

2015

A&A

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Aims. We present a new method for determining the magnetic field strength and plasma density in the solar zebra radio sources. Methods. Using the double plasma resonance (DPR) model of the zebra emission, we analytically derived the equations for computing the gyroharmonic number s of selected zebra lines and then solved these equations numerically. Results. The method was successfully tested on artificially generated zebras and then applied to observed ones. The magnetic field strength and plasma density in the radio sources were determined. Simultaneously, we evaluated the parameterwhere L n and L b are the characteristic scale-heights of the plasma density and magnetic field strength in the zebra source, respectively. Computations show that the maximum frequency of the low-polarized zebras is about 8 GHz, in very good agreement with observations. For the high-polarized zebras, this limit is about four times lower. Microwave zebras are preferentially generated in the regions with steep gradients of the plasma density, such as in the transition region. In models with smaller density gradients, such as those with a barometric density profile, the microwave zebras cannot be produced owing to the strong bremsstrahlung and cyclotron absorptions. We also show that our DPR model is able to explain the zebras with frequency-equidistant zebra lines.

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“…In agreement with Zheleznyakov & Zlotnik (1975), we assume that the distance l d can be computed from the formula…”

Section: Determining the Plasma Parametersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Determination of plasma parameters in solar zebra radio sources

Karlický

Yasnov

2015

A&A

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“…Problems appear with the interpretation of the frequently observed uncommon stripes of a ZP. For example, for explaining the so-called "tadpoles" (submerged in a developed ZP) special mechanisms were elaborated (Zheleznykov and Zlotnik, 1975a;. Rare attempts were made to explain other uncommon forms of ZPs (in the form of zigzags, complex splittings of stripes into the superfine structures).…”

Section: Introductionmentioning

confidence: 99%

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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“…Many mechanisms have been proposed to explain them (Kuijpers 1975;Zheleznyakov & Zlotnik 1975;Chernov 1976;Mollwo 1983;Winglee & Dulk 1986;Ledenev et al 2001;Yasnov & Karlický 2004;Bárta & Karlický 2006;LaBelle et al 2003;Kuznetsov & Tsap 2007;Zlotnik 2013); for review of these models, see Chernov (2010).…”

Section: Introductionmentioning

confidence: 99%

Radio continua modulated by waves: Zebra patterns in solar and pulsar radio spectra?

Karlický

2013

A&A

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Aims. We aim to answer the question how waves with plasma density variations affect the radio continua generated by the plasma emission mechanism. Methods. We built a simple semi-empirical model of the radio continuum modulation. Assuming that the waves with density variations are in the source of this radio continuum, we modeled the artificial radio spectrum, which we compared with observed spectra. Results. We show that the waves with density variations modulate the radio continua generated by the plasma emission mechanism. Considering a single slow magnetoacoustic wave, we model the radio spectra, which resemble solar zebra patterns. We show that this modulation generates zebra effects even when the radio continuum is composed of many spiky bursts. Generalizing from one single wave to a wave turbulence we find that the computed radio spectrum is similar to so-called lace bursts. Finally, using the same procedure, but for fast magnetoacoustic waves, we modeled the radio spectrum similar to that observed during the interpulse phase of the radio emission of the Crab Nebula pulsar.

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Cyclotron wave instability in the corona and origin of solar radio emission with fine structure

Cited by 142 publications

References 6 publications

Determination of plasma parameters in solar zebra radio sources

Determination of plasma parameters in solar zebra radio sources

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

Radio continua modulated by waves: Zebra patterns in solar and pulsar radio spectra?

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