Combined Whistler Heat Flux and Anisotropy Instabilities in Solar Wind

Sarfraz, M.; Yoon, Peter H.

doi:10.1029/2019ja027380

Cited by 13 publications

(6 citation statements)

References 65 publications

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“…Introducing a core anisotropy with T ⊥c /T c > 0 lowers the cyclotron-resonant core damping though and thus raises the growth rate. Treatments of the whistler heat-flux instability in bi-Maxwellian and κ-distributed plasmas confirm this picture (Shaaban et al, 2018;Sarfraz and Yoon, 2020). Quasi-linear models of the whistler heat-flux and electron whistler anisotropy instability driven by a combination of heat flux and anisotropy are also available (Shaaban et al, 2019b;Vasko et al, 2020).…”

Section: Whistler Heat-flux Instabilitymentioning

confidence: 75%

Electron-Driven Instabilities in the Solar Wind

Verscharen

Chandran²,

Boella³

et al. 2022

Front. Astron. Space Sci.

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The electrons are an essential particle species in the solar wind. They often exhibit non-equilibrium features in their velocity distribution function. These include temperature anisotropies, tails (kurtosis), and reflectional asymmetries (skewness), which contribute a significant heat flux to the solar wind. If these non-equilibrium features are sufficiently strong, they drive kinetic micro-instabilities. We develop a semi-graphical framework based on the equations of quasi-linear theory to describe electron-driven instabilities in the solar wind. We apply our framework to resonant instabilities driven by temperature anisotropies. These include the electron whistler anisotropy instability and the propagating electron firehose instability. We then describe resonant instabilities driven by reflectional asymmetries in the electron distribution function. These include the electron/ion-acoustic, kinetic Alfvén heat-flux, Langmuir, electron-beam, electron/ion-cyclotron, electron/electron-acoustic, whistler heat-flux, oblique fast-magnetosonic/whistler, lower-hybrid fan, and electron-deficit whistler instability. We briefly comment on non-resonant instabilities driven by electron temperature anisotropies such as the mirror-mode and the non-propagating firehose instability. We conclude our review with a list of open research topics in the field of electron-driven instabilities in the solar wind.

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Section: Whistler Heat-flux Instabilitymentioning

confidence: 75%

Electron-Driven Instabilities in the Solar Wind

Verscharen

Chandran²,

Boella³

et al. 2022

Front. Astron. Space Sci.

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“…As noted, the advantage of adopting the expanding-box paradigm is that one may work with the local wave kinetic equation, which is essentially the same as that of a uniform plasma theory (Seough & Yoon 2012;Moya & Navarro 2021;Navarro & Moya 2023). This implies that in other more complex situations, e.g., the solar-wind modeling with multiple ion (or electron) species, or charged particle species that contain relative drifts (Yoon et al 2015;Sarfraz et al 2016;Sarfraz 2018;Sarfraz & Yoon 2020;Shaaban et al 2021), we may formulate the basic equations either on the basis of expanding paradigm, or on the basis of steady-state macroscopic approach, but as far as the wave kinetic equation is concerned, one may choose to work in the framework of the local theory, which offers the advantage of mathematical simplicity.…”

Section: Adding Quasilinear Wave-particle Relaxation To the Expanding...mentioning

confidence: 99%

Expanding-box Quasilinear Model of the Solar Wind

Seough

Yoon

Nariyuki

et al. 2023

ApJ

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The expanding-box model of the solar wind has been adopted in the literature within the context of magnetohydrodynamics, hybrid, and full particle-in-cell simulations to investigate the dynamic evolution of the solar wind. The present paper extends such a method to the framework of self-consistent quasilinear kinetic theory. It is shown that the expanding-box quasilinear methodology is largely equivalent to the inhomogeneous steady-state quasilinear model discussed earlier in the literature, but a distinction regarding the description of wave dynamics between the two approaches is also found. The expanding-box quasilinear formalism is further extended to include the effects of a spiraling solar-wind magnetic field as well as collisional age effects. The present finding shows that the expanding-box quasilinear approach and the steady-state global-kinetic models may be employed interchangeably in order to address other more complex problems associated with the solar-wind dynamics.

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“…Shaaban & Lazar (2020) further considered the development of the whistler heat flux induced by the interplay of the electron beam and the electron temperature anisotropy, and found that the temperature anisotropy in the saturation stage is lower than threshold predicted by linear theory (also see Shaaban et al 2019a,d). Sarfraz & Yoon (2020) used quasilinear theory to explore the development of both forward and backward unstable whistler waves resulting from the electron beam and the electron anisotropic temperature, and also proposed that the saturation stage cannot be predicted by linear theory. Since the whistler heat flux instability is sensitive to the plasma parameters (V eb , A ec , A eb , β ec and β eb ), previous linear theories consider incomplete parameters, which may be one of reasons for discrepancy between linear and quasi-linear predictions.…”

Section: Linear Versus Quasi-linear Theory Predictionsmentioning

confidence: 99%

Electron Temperature Anisotropy and Electron Beam Constraints from Electron Kinetic Instabilities in the Solar Wind

Sun

Zhao

Liu

et al. 2020

ApJ

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Electron temperature anisotropies and electron beams are nonthermal features of the observed nonequilibrium electron velocity distributions in the solar wind. In collision-poor plasmas these nonequilibrium distributions are expected to be regulated by kinetic instabilities through wave-particle interactions. This study considers electron instabilities driven by the interplay of core electron temperature anisotropies and the electron beam, and firstly gives a comprehensive analysis of instabilities in arbitrary directions to the background magnetic field. It clarifies the dominant parameter regime (e.g., parallel core electron plasma beta β ec , core electron temperature anisotropy A ec ≡ T ec⊥ /T ec , and electron beam velocity V eb ) for each kind of electron instability (e.g., the electron beam-driven electron acoustic/magnetoacoustic instability, the electron beam-driven whistler instability, the electromagnetic electron cyclotron instability, the electron mirror instability, the electron firehose instability, and the ordinary-mode instability). It finds that the electron beam can destabilize electron acoustic/magnetoacoustic waves in the low-β ec regime, and whistler waves in the medium-and large-β ec regime. It also finds that a new oblique fast-magnetosonic/whistler instability is driven by the electron beam with V eb 7V A in a regime where β ec ∼ 0.1 − 2 and A ec < 1. Moreover, this study presents electromagnetic responses of each kind of electron instability. These results provide a comprehensive overview for electron instability constraints on core electron temperature anisotropies and electron beams in the solar wind.

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Combined Whistler Heat Flux and Anisotropy Instabilities in Solar Wind

Cited by 13 publications

References 65 publications

Electron-Driven Instabilities in the Solar Wind

Electron-Driven Instabilities in the Solar Wind

Expanding-box Quasilinear Model of the Solar Wind

Electron Temperature Anisotropy and Electron Beam Constraints from Electron Kinetic Instabilities in the Solar Wind

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