Stochastic acceleration in peaked spectrum

Zasenko, V.I.; Zagorodny, A. G.; Weiland, Jan

doi:10.1063/1.1931677

Cited by 7 publications

(4 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Some authors studied particle diffusion in given packets of waves with random phases and found discrepancies between the velocity diffusion coefficients calculated numerically and those predicted by the quasilinear theory [132][133][134][135][136][137]. Besides, the non classical nature of the diffusion at work was revealed [138,139] as, for example, the nonlinear time dependence of the particles' mean-square velocity variations (∆v) 2 . Another approach was proposed by the authors [77] as an alternative to the quasilinear theory.…”

Section: Particle Diffusion Processesmentioning

confidence: 99%

Turbulence and Microprocesses in Inhomogeneous Solar Wind Plasmas

Krafft

Volokitin

Gauthier

2019

Fluids

View full text Add to dashboard Cite

The random density fluctuations observed in the solar wind plasma crucially influence on the Langmuir wave turbulence generated by energetic electron beams ejected during solar bursts. Those are powerful phenomena consisting of a chain of successive processes leading ultimately to strong electromagnetic emissions. The small-scale processes governing the interactions between the waves, the beams and the inhomogeneous plasmas need to be studied to explain such macroscopic phenomena. Moreover, the complexity induced by the plasma irregularities requires to find new approaches and modelling. Therefore theoretical and numerical tools were built to describe the Langmuir wave turbulence and the beam’s dynamics in inhomogeneous plasmas, in the form of a self-consistent Hamiltonian model including a fluid description for the plasma and a kinetic approach for the beam. On this basis, numerical simulations were performed in order to shed light on the impact of the density fluctuations on the beam dynamics, the electromagnetic wave radiation, the generation of Langmuir wave turbulence, the waves’ coupling and decay phenomena involving Langmuir and low frequency waves, the acceleration of beam electrons, their diffusion mechanisms, the modulation of the Langmuir waveforms and the statistical properties of the radiated fields’ distributions. The paper presents the main results obtained in the form of a review.

show abstract

Section: Particle Diffusion Processesmentioning

confidence: 99%

Turbulence and Microprocesses in Inhomogeneous Solar Wind Plasmas

Krafft

Volokitin

Gauthier

2019

Fluids

View full text Add to dashboard Cite

show abstract

“…Thus, the zero approximation does not exist, and the particle motion is purely diffusive. This distinguishes the problem of particle diffusion in a velocity random field from the diffusion in a Langmuir type random field [8,9]. For the former, more runs are needed to obtain a smooth curve.…”

Section: Model For Numerical Simulationmentioning

confidence: 99%

Diffusion in a Frozen Random Velocity Field

2022

View full text Add to dashboard Cite

show abstract

“…In homogeneous plasmas, particle diffusion in wave packets was investigated with the help of numerical simulations [52,75,76]. The calculated velocity diffusion coefficients D (v) and those predicted by the quasilinear theory were shown to exhibit discrepancies in the case of given wavefields with random phases [77,78], revealing some non classical diffusion features [79,80].…”

Section: Dynamics Of the Turbulent Inhomogeneous Plasma Sourcementioning

confidence: 99%

Electromagnetic radiation from upper-hybrid wave turbulence in inhomogeneous solar plasmas

Krafft

Volokitin

2019

Plasma Phys. Control. Fusion

View full text Add to dashboard Cite

Type III solar radio bursts have been commonly observed in the solar wind and coronal plasmas. Electron beams accelerated in the Sun's atmosphere generate weakly magnetized Langmuir (upper-hybrid) wave turbulence producing in turn electromagnetic emissions at the electron plasma frequency ω p and its harmonic 2ω p , via successive processes involving interactions between the background plasma, the waves and the beam particles. The impact of the random density fluctuations inherent to the background plasma on these processes requires the development of novel approaches and models. Owing to a new theoretical modeling, the radiation efficiency of electromagnetic waves radiated at ω p from a plasma source with random density fluctuations and developed upper-hybrid wave turbulence is calculated analytically and numerically. It is shown that the maximum radiation efficiency at frequency ω p scales as the average level of density fluctuations and as the ratio (c/v T ) -2 (where v T is the thermal velocity). These scaling laws are found owing to two different and novel methods of determination of the electromagnetic radiation by turbulent inhomogeneous plasma sources through waves' transformations on randomly fluctuating density irregularities. These results contribute significantly to the understanding of the processes involved in the generation of Type III solar radio bursts. Their presentation is preceded by a summary of previous studies on the dynamics of beam-driven Langmuir turbulence in inhomogeneous solar plasmas.

show abstract

Stochastic acceleration in peaked spectrum

Cited by 7 publications

References 7 publications

Turbulence and Microprocesses in Inhomogeneous Solar Wind Plasmas

Turbulence and Microprocesses in Inhomogeneous Solar Wind Plasmas

Diffusion in a Frozen Random Velocity Field

Electromagnetic radiation from upper-hybrid wave turbulence in inhomogeneous solar plasmas

Contact Info

Product

Resources

About