One‐ and two‐dimensional simulations of electron beam instability: Generation of electrostatic and electromagnetic 2fp waves

Kasaba, Yasumasa; Matsumoto, Hiroshi; Omura, Yoshiharu

doi:10.1029/2000ja000329

Cited by 93 publications

(100 citation statements)

References 22 publications

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“…We propose that the demonstrated sensitivity, particularly to beam density, is the underlying explanation as to why Ganse et al (2012b) have reported being able to find no evidence consistent with plasma emission in PIC simulations. Furthermore, we caution that as previous studies such as Kasaba et al (2001), Umeda (2010) have interpreted their results as signs of emission in similar parameter regimes to Run 2 but not reported on noise thresholds, it is unclear if such systems actually generate efficient plasma emission that is compatible with observed radio emission. Indeed, typical setups (with dense beams) are closer to those used in Run 2 (i.e., the case where we find limited evidence for fundamental emission, and no evidence for harmonic emission).…”

Section: Discussionmentioning

confidence: 73%

“…In the most extreme, some authors interpret the results of their experiments as evidence supporting the three-wave based mechanisms (Kasaba et al 2001;Umeda 2010), whereas others report that the such processes do not proceed in their simulations, and rather must invoke different mechanisms to produce emission; such as the requirement for a counter-propagating beam (Ganse et al 2012b(Ganse et al ,a, 2014Timofeev & Annenkov 2014), or linear mode conversion off density inhomogeneities as per Sakai et al (2005). Although, note that in the latter work they did not present results for a homogeneous setup, so arguably the underlying process responsible for emission in their work is not conclusively demonstrated.…”

Section: Introductionmentioning

confidence: 97%

“…This is of crucial importance as noise organising itself as electromagnetic waves (most obviously manifest as power enhancements along dispersion curves in (ω, k)-diagrams) is a typical and unavoidable feature of PIC simulations. Secondly, pseudoparticle numbers used are typically low (e.g., Kasaba et al (2001) uses 16 particles per cell for background partxicles and 4 for the beam particles, and Umeda (2010) uses 256 particles per cell per species), and few papers report convergence testing of results. Umeda (2010) reported that increasing pseudoparticle numbers diminished the signal associated with harmonic emission.…”

Section: Introductionmentioning

confidence: 99%

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Self-consistent particle-in-cell simulations of fundamental and harmonic plasma radio emission mechanisms

Thurgood

Tsiklauri

2015

A&A

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Aims. The simulation of three-wave interaction based plasma emission, thought to be the underlying mechanism for Type III solar radio bursts, is a challenging task requiring fully-kinetic, multi-dimensional models. This paper aims to resolve a contradiction in past attempts, whereby some studies indicate that no such processes occur. Methods. We self-consistently simulate three-wave based plasma emission through all stages by using 2D, fully kinetic, electromagnetic particle-in-cell simulations of relaxing electron beams using the EPOCH2D code.Results. Here we present the results of two simulations;, which we find to permit and prohibit plasma emission respectively. We show that the possibility of plasma emission is contingent upon the frequency of the initial electrostatic waves generated by the bump-in-tail instability, and that these waves may be prohibited from participating in the necessary three-wave interactions due to frequency conservation requirements. In resolving this apparent contradiction through a comprehensive analysis, in this paper we present the first self-consistent demonstration of fundamental and harmonic plasma emission from a single-beam system via fully kinetic numerical simulation. We caution against simulating astrophysical radio bursts using unrealistically dense beams (a common approach which reduces run time), as the resulting non-Langmuir characteristics of the initial wave modes significantly suppresses emission. Comparison of our results also indicates that, contrary to the suggestions of previous authors, an alternative plasma emission mechanism based on two counter-propagating beams is unnecessary in an astrophysical context. Finally, we also consider the action of the Weibel instability which generates an electromagnetic beam mode. As this provides a stronger contribution to electromagnetic energy than the emission, we stress that evidence of plasma emission in simulations must disentangle the two contributions and not simply interpret changes in total electromagnetic energy as evidence of plasma emission.

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Section: Discussionmentioning

confidence: 73%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Self-consistent particle-in-cell simulations of fundamental and harmonic plasma radio emission mechanisms

Thurgood

Tsiklauri

2015

A&A

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“…Although the essential theoretical framework based upon EM weak turbulence theory, which describes the entire process starting from the beam-generated Langmuir turbulence to the radiation generation, was available, complete numerical solution of the entire set of EM weak turbulence equations have not been done until quite recently, when Ziebell et al (2014aZiebell et al ( ,b,c, 2015 numerically solved the complete equations of EM weak turbulence theory for the first time. It should be mentioned that a few authors carried out direct EM particle-in-cell (PIC) simulations to characterize the nonlinear behavior of the plasma emission process (Kasaba et al 2001;Karlický & Vandas 2007;Rhee et al 2009a,b;Umeda 2010;Ganse et al 2012aGanse et al ,b, 2014. The full numerical solution of the analytical EM weak turbulence equations by Ziebell et al (2014aZiebell et al ( , 2015 complements these PIC simulation efforts.…”

Section: Introductionmentioning

confidence: 99%

Two-dimensional time evolution of beam-plasma instability in the presence of binary collisions

Tigik

Ziebell

Yoon

et al. 2016

A&A

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Energetic electrons produced during solar flares are known to be responsible for generating solar type III radio bursts. The radio emission is a byproduct of Langmuir wave generation via beam-plasma interaction and nonlinear wave-wave and wave-particle interaction processes. In addition to type III radio bursts, electrons traveling downwards toward the chromosphere lead to the hard X-ray emission via electron-ion collisions. Recently, the role of Langmuir waves on the X-ray-producing electrons has been identified as important, because Langmuir waves may alter the electron distribution, thereby affecting the X-ray profile. Both Coulomb collisions and wave-particle interactions lead electrons to scattering and energy exchange that necessitates considering the two-dimensional (2D) problem in velocity space. The present paper investigates the influence of binary collisions on the beam-plasma instability development in 2D in order to elucidate the nonlinear dynamics of Langmuir waves and binary collisions. The significance of the present findings in the context of solar physics is discussed.

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“…(3) Full kinetic simulation approach of type III bursts (Kasaba, Matsumoto, and Omura, 2001;Sakai, Kitamoto, and Saito, 2005;Rhee et al, 2009;Umeda, 2010) to this date used Particle-In-Cell (PIC) numerical method. This effort is mainly focused on understanding of basic physics rather than direct comparison with the observations because the size of simulation domain of the models corresponds to only few 1000 Debye lengths which is roughly 1/10 10 th of 1 AU.…”

Section: Introductionmentioning

confidence: 99%

Vlasov – Maxwell, Self-consistent Electromagnetic Wave Emission Simulations in the Solar Corona

Tsiklauri

2010

Sol Phys

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1.5D Vlasov-Maxwell simulations are employed to model electromagnetic emission generation in a fully self-consistent plasma kinetic model for the first time in the solar physics context. The simulations mimic the plasma emission mechanism and Larmor drift instability in a plasma thread that connects the Sun to Earth with the spatial scales compressed appropriately. The effects of spatial density gradients on the generation of electromagnetic radiation are investigated. It is shown that 1.5D inhomogeneous plasma with a uniform background magnetic field directed transverse to the density gradient is aperiodically unstable to Larmor-drift instability. The latter results in a novel effect of generation of electromagnetic emission at plasma frequency. The generated perturbations consist of two parts: (i) non-escaping (trapped) Langmuir type oscillations which are localised in the regions of density inhomogeneity, and are highly filamentary, with the period of appearance of the filaments close to electron plasma frequency in the dense regions; and (ii) escaping electromagnetic radiation with phase speeds close to the speed of light. When density gradient is removed (i.e. when plasma becomes stable to Larmor-drift instability) and a low density super-thermal, hot beam is injected along the domain, in the direction perpendicular to the magnetic field, plasma emission mechanism generates non-escaping Langmuir type oscillations which in turn generate escaping electromagnetic radiation. It is found that in the spatial location where the beam is injected, the standing waves, oscillating at the plasma frequency, are excited. These can be used to interpret the horizontal strips (the narrowband line emission) observed in some dynamical spectra. Quasilinear theory predictions: (i) the electron free streaming and (ii) the beam long relaxation time, in accord with the analytic expressions, are corroborated via direct, fully-kinetic simulation. Finally, the interplay of Larmordrift instability and plasma emission mechanism is studied by considering dense electron beam in the Larmor-drift unstable (inhomogeneous) plasma. The latter case enables one to study the deviations from the quasilinear theory.

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One‐ and two‐dimensional simulations of electron beam instability: Generation of electrostatic and electromagnetic 2f_p waves

Cited by 93 publications

References 22 publications

Self-consistent particle-in-cell simulations of fundamental and harmonic plasma radio emission mechanisms

Self-consistent particle-in-cell simulations of fundamental and harmonic plasma radio emission mechanisms

Two-dimensional time evolution of beam-plasma instability in the presence of binary collisions

Vlasov – Maxwell, Self-consistent Electromagnetic Wave Emission Simulations in the Solar Corona

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