Numerical consideration of quasilinear electron cloud dynamics in plasma

Kontar, Eduard P.

doi:10.1016/s0010-4655(01)00214-4

Cited by 19 publications

(24 citation statements)

References 17 publications

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“…The system of kinetic equations is reduced to dimensionless form and integrated using finite difference schemes. For the numerical time integration we used a method similar to the one used in [34] and the quasi-linear terms are integrated using methods described in [35]. Previous results [34,35] are found in full agreement with the corresponding limiting cases of our calculations.…”

Section: Numerical Resultssupporting

confidence: 69%

“…For the numerical time integration we used a method similar to the one used in [34] and the quasi-linear terms are integrated using methods described in [35]. Previous results [34,35] are found in full agreement with the corresponding limiting cases of our calculations. The electron beam and plasma parameters are taken typical for the conditions in the solar corona [36,37].…”

Section: Numerical Resultssupporting

confidence: 69%

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Nonlinear development of electron-beam-driven weak turbulence in an inhomogeneous plasma

Kontar

Pécseli

2002

Phys. Rev. E

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The self-consistent description of Langmuir wave and ion-sound wave turbulence in the presence of an electron beam is presented for inhomogeneous nonisothermal plasmas. Full numerical solutions of the complete set of kinetic equations for electrons, Langmuir waves, and ion-sound waves are obtained for an inhomogeneous unmagnetized plasma. The results show that the presence of inhomogeneity significantly changes the overall evolution of the system. The inhomogeneity is effective in shifting the wave numbers of the Langmuir waves, and can thus switch between different processes governing the weakly turbulent state. The results can be applied to a variety of plasma conditions, where we choose solar coronal parameters as an illustration, when performing the numerical analysis.

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Section: Numerical Resultssupporting

confidence: 69%

Section: Numerical Resultssupporting

confidence: 69%

Nonlinear development of electron-beam-driven weak turbulence in an inhomogeneous plasma

Kontar

Pécseli

2002

Phys. Rev. E

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“…Zheleznyakov & Zaitsev 1970;Smith 1970;Zaitsev et al 1972;Smith et al 1976;Melrose 1980bMelrose , 1987Goldman 1983;Dulk 1985;Kontar et al 1998;Mel'Nik 2003;Ledenev et al 2004) and continues to develop with the advent of numerical simulations (e.g. Takakura & Shibahashi 1976;Magelssen & Smith 1977;Grognard 1985;Robinson 1992;Kontar 2001c;Li et al 2008;Kontar & Reid 2009;Tsiklauri 2010Tsiklauri , 2011Ratcliffe et al 2012;Li & Cairns 2014;.…”

Section: Introductionmentioning

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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“…Other studies 17,18 indicated that these effects could be important. Those results rely on an entirely different computational model 60 based on the weak turbulence approximation. We have studied more localized density gradients in ion density, but these were of scale lengths too short to be relevant for those previous studies, 17,18 and no conclusive results can be presented.…”

Section: Discussionmentioning

confidence: 99%

Nonlinear beam generated plasma waves as a source for enhanced plasma and ion acoustic lines

et al. 2011

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Observations by, for instance, the EISCAT Svalbard Radar (ESR) demonstrate that the symmetry of the naturally occurring ion line in the polar ionosphere can be broken by an enhanced, nonthermal, level of fluctuations (naturally enhanced ion-acoustic lines, NEIALs). It was in many cases found that the entire ion spectrum can be distorted, also with the appearance of a third line, corresponding to a propagation velocity significantly slower than the ion acoustic sound speed. It has been argued that selective decay of beam excited primary Langmuir waves can explain some phenomena similar to those observed. We consider a related model, suggesting that a primary nonlinear process can be an oscillating two-stream instability, generating a forced low frequency mode that does not obey any ion sound dispersion relation. At later times, the decay of Langmuir waves can give rise also to enhanced asymmetric ion lines. The analysis is based on numerical results, where the initial Langmuir waves are excited by a cold dilute electron beam. By this numerical approach, we can detect fine details of the physical processes, in particular, demonstrate a strong space-time intermittency of the electron waves in agreement with observations. Our code solves the full Vlasov equation for electrons and ions, with the dynamics coupled through the electrostatic field derived from Poisson's equation. The analysis distinguishes the dynamics of the background and beam electrons. This distinction simplifies the analysis for the formulation of the weakly nonlinear analytical model for the oscillating two-stream instability. The results have general applications beyond their relevance for the ionospheric observations.

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Numerical consideration of quasilinear electron cloud dynamics in plasma

Cited by 19 publications

References 17 publications

Nonlinear development of electron-beam-driven weak turbulence in an inhomogeneous plasma

Nonlinear development of electron-beam-driven weak turbulence in an inhomogeneous plasma

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

Nonlinear beam generated plasma waves as a source for enhanced plasma and ion acoustic lines

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