Shaping the solar wind temperature anisotropy by the interplay of electron and proton instabilities

Shaaban, S. M.; Lazar, M.; Poedts, Stefaan; Elhanbaly, A.

doi:10.1007/s10509-016-2994-7

Cited by 31 publications

(40 citation statements)

References 32 publications

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“…Other extensions include inverse correlations using non-Maxwellian models by Xiao et al (2006Xiao et al ( , 2007, Lazar (2012); empirical inverse correlations for electrons and high-frequency instabilities by Gary et al (2005) and Š tverák et al (2008); modification of the inverse correlation by including binary collisional effects by ; efforts to rigorously calculate the inverse correlation by Isenberg (Isenberg 2012;Isenberg et al 2013) who sought to obtain a rigorous asymptotic solution of the plasma subjected to linear instability condition; including the effects of streaming population on the stability condition by Hadi et al (2014), , and Vafin et al (2015); the mutual dynamical influence of electrons and ions, considered by Michno et al (2014), Maneva et al (2016), and Shaaban et al (2016Shaaban et al ( , 2017, etc. Fig.…”

Section: Introductionmentioning

confidence: 99%

Kinetic instabilities in the solar wind driven by temperature anisotropies

Yoon

2017

Rev. Mod. Plasma Phys.

104

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The present paper comprises a review of kinetic instabilities that may be operative in the solar wind, and how they influence the dynamics thereof. The review is limited to collective plasma instabilities driven by the temperature anisotropies. To limit the scope even further, the discussion is restricted to the temperature anisotropy-driven instabilities within the model of bi-Maxwellian plasma velocity distribution function. The effects of multiple particle species or the influence of field-aligned drift will not be included. The field-aligned drift or beam is particularly prominent for the solar wind electrons, and thus ignoring its effect leaves out a vast portion of important physics. Nevertheless, for the sake of limiting the scope, this effect will not be discussed. The exposition is within the context of linear and quasilinear Vlasov kinetic theories. The discussion does not cover either computer simulations or data analyses of observations, in any systematic manner, although references will be made to published works pertaining to these methods. The scientific rationale for the present analysis is that the anisotropic temperatures associated with charged particles are pervasively detected in the solar wind, and it is one of the key contemporary scientific research topics to correctly characterize how such anisotropies are generated, maintained, and regulated in the solar wind. The present article aims to provide an up-to-date theoretical development on this research topic, largely based on the author's own work.

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Section: Introductionmentioning

confidence: 99%

Kinetic instabilities in the solar wind driven by temperature anisotropies

Yoon

2017

Rev. Mod. Plasma Phys.

104

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“…The effects of suprathermal protons become significant when the instability is mainly controlled by the anisotropic protons: growth rates and the range of unstable wave numbers are enhanced with decreasing κ p , but this stimulation is less prominent than that determined by the suprathermal electrons. Instead, a Kappa‐2 approach leads to nonuniform variations of growth rates (as for other kinetic instabilities (Lazar et al, ; Shaaban et al, )); the effects of suprathermal populations cannot be easily defined and we therefore avoid to discuss here.…”

Section: Discussionmentioning

confidence: 99%

“…Here the instability thresholds are derived only for a Kappa‐1 approach (with κ ‐dependent temperatures), which appear to be more realistic; see the arguments above. These thresholds are fitted to an inverse correlation law (Gary & Wang, ; Shaaban et al, )

A_{p} = 1 + \frac{a}{β_{p, ∥}},

where the fitting parameters a and b are tabulated in Table .…”

Section: Mirror Instabilitymentioning

confidence: 99%

“…To motivate the present study, section 3 presents a short comparative analysis of the EMIC and mirror instabilities under the effects of anisotropic electrons (

A_{e} ≳ 1

) and their suprathermal components. The EMIC growth rates may be markedly inhibited by these effects, indicating a lower effectiveness of this instability (Shaaban et al, , ). Mirror instability resulted from the interplay of anisotropic electrons and protons, and their suprathermal components are characterized in section 4.…”

Section: Introductionmentioning

confidence: 99%

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Stimulated Mirror Instability From the Interplay of Anisotropic Protons and Electrons, and their Suprathermal Populations

et al. 2018

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Mirror instability driven by the temperature anisotropy of protons can offer a plausible explanation for the mirror‐like fluctuations observed in planetary magnetosheaths. In the present paper we invoke a realistic kinetic approach which can reproduce nonthermal features of plasma particles reported by the observations, i.e., temperature anisotropies and suprathermal populations. Seeking accuracy, a numerical analysis is performed using an advanced code named DSHARK, recently proposed to resolve the linear dispersion and stability for an arbitrary propagation in bi‐Kappa distributed electron‐proton plasmas. The stimulating effect of the anisotropic bi‐Maxwellian electrons reported in Remya et al. (2013, https://doi.org/10.1002/jgra.50091) is markedly enhanced in the presence of suprathermal electrons described by the bi‐Kappa distribution functions. The influence of suprathermal protons is more temperate, but overall, present results demonstrate that these sources of free energy provide natural conditions for a stimulated mirror instability, more efficient than predicted before and capable to compete with other instabilities (e.g., the electromagnetic ion‐cyclotron instability) and mechanisms of relaxation.

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“…Understanding the apparent failure of the parallel propagating instabilities, EMIC and PFHI, to constrain proton temperature anisotropies in the solar wind, poses a challenge, which still requires further investigation. Several solutions have been suggested to resolve this issue, such as the inclusion of electron temperature anisotropies (Michno et al, ; Shaaban et al, ) or minor ion anisotropies (Matteini et al, ). Yoon et al () give a concise review of possible explanations and put forth another approach imposing a time‐varying background magnetic field.…”

Section: Introductionmentioning

confidence: 99%

On the Quasi‐linear Saturation of the Parallel Proton Firehose Instability Using a Full‐f Approach

Astfalk

Jenko

2018

JGR Space Physics

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A classic example for the application of quasi‐linear theory to electromagnetic wave‐particle interactions, the saturation of the parallel proton firehose instability, is usually considered in the long‐wavelength approximation although for βfalse∥,normalp≲25 this instability is dominated by anomalous cyclotron resonance, which invalidates a macroscopic treatment (Gary et al., 1998, https://doi.org/10.1029/98JA01174). To relax the long‐wavelength approximation, Seough et al. (2015, https://doi.org/10.1063/1.4905230) solved the microscopic weak turbulence kinetic equation to model the temperature anisotropy reduction of the firehose also in the resonant regime. However, the employed moment‐kinetic approach assumes the preservation of the initially bi‐Maxwellian shape of the underlying proton velocity distribution throughout the saturation process, leading to poor results for low β∥,p. In this work, we lift the limitations of the moment‐kinetic approach and we demonstrate that allowing for distribution deformation due to anomalous cyclotron‐resonant scattering greatly improves the predictions of the kinetic quasi‐linear model except for cases of very strong firehose growth. We conclude that quasi‐linear theory can be a valid model for studying the parallel firehose saturation even in the strongly cyclotron‐resonant regime as long as the initial temperature anisotropy is not too large.

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Shaping the solar wind temperature anisotropy by the interplay of electron and proton instabilities

Cited by 31 publications

References 32 publications

Kinetic instabilities in the solar wind driven by temperature anisotropies

Kinetic instabilities in the solar wind driven by temperature anisotropies

Stimulated Mirror Instability From the Interplay of Anisotropic Protons and Electrons, and their Suprathermal Populations

On the Quasi‐linear Saturation of the Parallel Proton Firehose Instability Using a Full‐f Approach

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