Origin of plasma-wave clumping in type III solar radio burst sources

Smith, D. F.; Sime, D. G.

doi:10.1086/157463

Cited by 63 publications

(41 citation statements)

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“…In particular, density fluctuations in the plasma can shift Langmuir waves out of resonance with the electrons (e.g. Smith & Sime, 1979;Muschietti et al, 1985). Because the growth rate of Langmuir waves is proportional to their current level at a given wavenumber, this can suppress the instability (in line with Kontar, 2001b;Ledenev et al, 2004;Li et al, 2006b;Reid & Kontar, 2010).…”

Section: Electron Beam Persistencementioning

confidence: 99%

“…Because the growth rate of Langmuir waves is proportional to their current level at a given wavenumber, this can suppress the instability (in line with Kontar, 2001b;Ledenev et al, 2004;Li et al, 2006b;Reid & Kontar, 2010). The density fluctuations can be either wave modes with wavelengths comparable to the Debye length (Vedenov et al, 1967;Goldman & Dubois, 1982;Yoon et al, 2005), or longer wavelength inhomogeneities (Ryutov, 1969;Nishikawa & Ryutov, 1976;Smith & Sime, 1979;Kontar, 2001a;Kontar et al, 2012). In the latter case, the Langmuir wave evolution can be described in the WKB approximation by (e.g.…”

Section: Electron Beam Persistencementioning

confidence: 99%

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A review of solar type III radio bursts

Reid

Ratcliffe

2014

Res. Astron. Astrophys.

341

217

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Solar type III radio bursts are an important diagnostic tool in the understanding of solar accelerated electron beams. They are a signature of propagating beams of nonthermal electrons in the solar atmosphere and the solar system. Consequently, they provide information on electron acceleration and transport, and the conditions of the background ambient plasma they travel through. We review the observational properties of type III bursts with an emphasis on recent results and how each property can help identify attributes of electron beams and the ambient background plasma. We also review some of the theoretical aspects of type III radio bursts and cover a number of numerical efforts that simulate electron beam transport through the solar corona and the heliosphere.

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Section: Electron Beam Persistencementioning

confidence: 99%

Section: Electron Beam Persistencementioning

confidence: 99%

A review of solar type III radio bursts

Reid

Ratcliffe

2014

Res. Astron. Astrophys.

341

217

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“…Density fluctuations in the background plasma are known to decrease the level of Langmuir waves induced by an electron beam (e.g. Ryutov 1969;Smith & Sime 1979;Melrose 1980a;Kontar 2001a;Reid & Kontar 2010Li et al 2012;Ratcliffe et al 2012). Langmuir waves are shifted out of resonance with the electron beam by the density fluctuations that results in a decreased level of Langmuir wave turbulence.…”

Section: Density Fluctuations In the Background Plasmamentioning

confidence: 99%

Stopping frequency of type III solar radio bursts in expanding magnetic flux tubes

Reid

Kontar

2015

A&A

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Aims. Understanding the properties of type III radio bursts in the solar corona and interplanetary space is one of the best ways to remotely deduce the characteristics of solar accelerated electron beams and the solar wind plasma. One feature of all type III bursts is the lowest frequency they reach (or stopping frequency). This feature reflects the distance from the Sun that an electron beam can drive the observable plasma emission mechanism. The stopping frequency has never been systematically studied before from a theoretical perspective. Methods. Using numerical kinetic simulations, we explore the different parameters that dictate how far an electron beam can travel before it stops inducing a significant level of Langmuir waves, responsible for plasma radio emission. We use the quasilinear approach to model the resonant interaction between electrons and Langmuir waves self-consistently in inhomogeneous plasma, and take into consideration the expansion of the guiding magnetic flux tube and the turbulent density of the interplanetary medium. Results. We find that the rate of radial expansion has a significant effect on the distance an electron beam travels before enhanced levels of Langmuir waves, hence radio waves, cease. Radial expansion of the guiding magnetic flux tube rarefies the electron stream to the extent that the density of non-thermal electrons is too low to drive Langmuir wave production. The initial conditions of the electron beam have a significant effect, where decreasing the beam density or increasing the spectral index of injected electrons would cause higher type III stopping frequencies. We also demonstrate how the intensity of large-scale density fluctuations increases the highest frequency to which Langmuir waves can be driven by the beam and how the magnetic field geometry can be the cause of type III bursts that are only observed at high coronal frequencies.

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“…the local plasma frequency change due to the inhomogeneity is less than the thermal width of the plasma frequency (8). The value α is taken to be 10 −3 , which is considered to be a typical value for solar coronal observations (Cronyn 1972;Smith & Sime 1979). The spatial period of the plasma fluctuations ∆x = d/12 is taken to be less than the initial size of the electron cloud.…”

Section: Propagation Of An Electron Cloudmentioning

confidence: 99%

“…In the treatment presented here, quasilinear relaxation is a dominant process and density inhomogeneities are too weak to suppress the instability. Indeed, observations of interplanetary scintillations from extragalactic radio sources (Cronyn 1972) lead to an average value of ∆n/n of the order of 10 −3 (Smith & Sime 1979). Nevertheless, the low intensity density fluctuations lead to significant spatial redistribution of wave energy.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of electron beams in the solar corona plasma with density fluctuations

Kontar¹

2001

A&A

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Abstract. The problem of beam propagation in a plasma with small scale and low intensity inhomogeneities is investigated. It is shown that the electron beam propagates in a plasma as a beam-plasma structure and is a source of Langmuir waves. The plasma inhomogeneity changes the spatial distribution of the waves. The spatial distribution of the waves is fully determined by the distribution of plasma inhomogeneities. The possible applications to the theory of radio emission associated with electron beams are discussed.

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Origin of plasma-wave clumping in type III solar radio burst sources

Cited by 63 publications

References 0 publications

A review of solar type III radio bursts

A review of solar type III radio bursts

Stopping frequency of type III solar radio bursts in expanding magnetic flux tubes

Dynamics of electron beams in the solar corona plasma with density fluctuations

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