Temperature-dependent Saturation of Weibel-type Instabilities in Counter-streaming Plasmas

Skoutnev, Valentin; Hakim, Ammar; Juno, James; TenBarge, Jason

doi:10.3847/2041-8213/ab0556

Cited by 12 publications

(19 citation statements)

References 25 publications

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“…Less energetic beams with drifting (or beaming) speed lower than thermal speed have not been explored in detail in the past. Such beams guided by the magnetic fields lines can be associated with the incipient beaming formation in plasmas [26][27][28]. In this case the electrostatic instability does not easily develop, but the full wavevector spectrum of electromagnetic (EM) fluctuations may unveil electromagnetic growing modes expected to destabilize the more or less symmetric plasma beams [24].…”

Section: Introductionmentioning

confidence: 99%

A firehose-like aperiodic instability of the counter-beaming electron plasmas

Lopez¹,

Lazar²,

Shaaban³

et al. 2020

Plasma Phys. Control. Fusion

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Depending on the physical conditions involved the beam plasma systems may reveal new unstable regimes triggered by the wave instabilities of different nature. We show through linear theory and numerical simulations the existence of an aperiodic electromagnetic instability which solely develops and control the stability of two symmetric plasma populations counter-moving along the regular magnetic field with a relative drift, v d , small enough to not exceed the particle thermal speed, αe. Emerging at highly oblique angles this mode resembles properties of the aperiodic firehose instability driven by temperature anisotropy. The high growth rates achieved with increasing the relative drift or/and decreasing the plasma beta parameter lead to significant saturation levels of the fluctuating magnetic field power, which explain the relative fast relaxation of electrons. For v d > αe this instability can coexist with the electrostatic two-stream instability, dominating the long-term dynamics of the plasma as soon as v d has relaxed to values smaller than the thermal speed.

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Section: Introductionmentioning

confidence: 99%

A firehose-like aperiodic instability of the counter-beaming electron plasmas

Lopez¹,

Lazar²,

Shaaban³

et al. 2020

Plasma Phys. Control. Fusion

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“…We wish to emphasize that the results of this study alone do not yet answer the question of the source of disagreement between Skoutnev et al (2019) and Kato & Takabe (2008) in the non-relativistic, cold parameter regime. On one hand, particle noise appears to be a possible component of the disagreement, with the potential for a noise-generated magnetic field to modify the dynamics in a driven system such as a Weibel-mediated collisionless shock.…”

Section: Discussion and Summarymentioning

confidence: 76%

“…As the temperature of the beams is reduced, the growth rates of a spectrum of oblique modes increase, modes which arise due to perturbations between parallel (two-stream) and perpendicular (filamentation) to the drift direction (Bret 2009). These hybrid two-stream-filamentation modes begin to have comparable growth rates to the two-stream instability -see figure 1 in Skoutnev et al (2019). These fast-growing oblique modes rapidly deplete the free energy in the inter-penetrating flows, eliminating the channel for magnetic field growth via a combination of the more slowly growing filamentation instability and secular Weibel instability from the residual temperature anisotropy of saturated two-stream modes studied in, e.g.…”

Section: Introductionmentioning

confidence: 90%

“…We are inspired by the recently reported disagreement between the continuum kinetic simulations performed in Skoutnev et al (2019) and past PIC calculations in a similar parameter regime (Kato & Takabe 2008) of the competition of a class of Weibel-type instabilities driven by counter-streaming beams of plasmas (Weibel 1959;Bornatici & Lee 1970;Davidson et al 1972). These Weibel-type instabilities are an interesting class of plasma instabilities, serving as a possible explanation for the observed magnetic fields in gamma ray bursts (Medvedev & Loeb 1999) and pulsar wind outflows (Kazimura et al 1998), and as a potential source of the seed magnetic field in a cosmological context (Schlickeiser & Shukla 2003;Lazar et al 2009).…”

Section: Introductionmentioning

confidence: 99%

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Noise-induced magnetic field saturation in kinetic simulations

et al. 2020

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Monte Carlo methods are often employed to numerically integrate kinetic equations, such as the particle-in-cell method for the plasma kinetic equation, but these methods suffer from the introduction of counting noise to the solution. We report on a cautionary tale of counting noise modifying the nonlinear saturation of kinetic instabilities driven by unstable beams of plasma. We find a saturated magnetic field in under-resolved particle-in-cell simulations due to the sampling error in the current density. The noise-induced magnetic field is anomalous, as the magnetic field damps away in continuum kinetic and increased particle count particle-in-cell simulations. This modification of the saturated state has implications for a broad array of astrophysical phenomena beyond the simple plasma system considered here, and it stresses the care that must be taken when using particle methods for kinetic equations.

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“…2019; Skoutnev et al. 2019). As stated above, Eulerian algorithms generally require a computational cost significantly large as compared to PIC codes.…”

Section: Introductionmentioning

confidence: 99%

ViDA: a Vlasov–DArwin solver for plasma physics at electron scales

et al. 2019

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We present a Vlasov-DArwin numerical code (ViDA) specifically designed to address plasma physics problems, where small-scale high accuracy is requested even during the non linear regime to guarantee a clean description of the plasma dynamics at fine spatial scales. The algorithm provides a low-noise description of proton and electron kinetic dynamics, by splitting in time the multi-advection Vlasov equation in phase space. Maxwell equations for the electric and magnetic fields are reorganized according to Darwin approximation to remove light waves. Several numerical tests show that ViDA successfully reproduces the propagation of linear and nonlinear waves and captures the physics of magnetic reconnection. We also discuss preliminary tests of the parallelization algorithm efficiency, performed at CINECA on the Marconi-KNL cluster. ViDA will allow to run Eulerian simulations of a non-relativistic fully-kinetic collisionless plasma and it is expected to provide relevant insights on important problems of plasma astrophysics such as, for instance, the development of the turbulent cascade at electron scales and the structure and dynamics of electron-scale magnetic reconnection, such as the electron diffusion region.

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Temperature-dependent Saturation of Weibel-type Instabilities in Counter-streaming Plasmas

Cited by 12 publications

References 25 publications

A firehose-like aperiodic instability of the counter-beaming electron plasmas

A firehose-like aperiodic instability of the counter-beaming electron plasmas

Noise-induced magnetic field saturation in kinetic simulations

ViDA: a Vlasov–DArwin solver for plasma physics at electron scales

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