Magnetic Alfvén‐cyclotron fluctuations of anisotropic nonthermal plasmas

Navarro, R.; Muñoz, Vı́ctor; Araneda, J. A.; Viñas, A. F.; Moya, P. S.; Valdivia, J. A.

doi:10.1002/2014ja020550

Cited by 27 publications

(35 citation statements)

References 73 publications

(136 reference statements)

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“…Following standard second‐order correlation procedure, the classical spectral power distribution of electric field fluctuations per species s in a magnetized nonisothermal and homogeneous anisotropic plasma can be generally expressed [see Sitenko , ] in terms of the fluctuation‐dissipation theorem:

{(〈〉, δ E_{i} δ E_{j}^{*})}_{(ω, \overset{k}{true})}^{(s)} = 4 πi \frac{k_{B} T_{⊥ s}}{ω} Λ_{(0)}^{- 1} ((), Λ_{jm}^{- 1} χ_{mi}^{(s)} - χ_{im}^{(s) *} Λ_{mj}^{- 1 *}),

where ω is the frequency of the fluctuations,

Λ_{ij}^{- 1}

are the components of the inverse of the dispersion tensor,

Λ_{(0)}^{- 1}

is a diagonal inverse dispersion tensor of free space (vacuum), χ ( s ) is the electromagnetic susceptibility tensor per species s , T ⊥ s is the species perpendicular temperature and k B is the Boltzmann constant. The bracket 〈⋯〉 represents the statistical space‐time ensemble average for each frequency and wave vector [see also Navarro et al , ].…”

Section: Theory Of Electromagnetic Fluctuations In Plasmasmentioning

confidence: 99%

“…where is the frequency of the fluctuations, Λ −1 ij are the components of the inverse of the dispersion tensor, Λ −1 (0) is a diagonal inverse dispersion tensor of free space (vacuum), (s) is the electromagnetic susceptibility tensor per species s, T ⊥s is the species perpendicular temperature and k B is the Boltzmann constant. The bracket ⟨· · ·⟩ represents the statistical space-time ensemble average for each frequency and wave vector [see also Navarro et al, 2015].…”

Section: Theory Of Electromagnetic Fluctuations In Plasmasmentioning

confidence: 99%

“…In this paper, we use Sitenko [] fluctuation theory and use the formalism described by Schlickeiser and Yoon [] for unmagnetized plasmas, and Navarro et al [] and Navarro et al [] for magnetized plasmas composed of protons and electrons emphasizing the high‐frequency parallel‐propagating electron‐driven whistler‐cyclotron and firehose fluctuations for arbitrary bi‐Maxwellian and thermally anisotropic Tsallis‐kappa‐like distribution functions to explain the correspondence of the temperature anisotropy and threshold of magnetic fluctuations in the solar wind and magnetosphere. We then compare our results to those considered by Navarro et al [] for low‐frequency Alfvén cyclotron waves and Viñas et al [] for high‐frequency whistler waves, respectively, when the spectral κ index tends to infinity and the system becomes isotropic (i.e., Maxwellian).…”

Section: Introductionmentioning

confidence: 99%

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Electromagnetic fluctuations of the whistler‐cyclotron and firehose instabilities in a Maxwellian and Tsallis‐kappa‐like plasma

et al. 2015

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Observed electron velocity distributions in the Earth's magnetosphere and the solar wind exhibit a variety of nonthermal features which deviate from thermal equilibrium, for example, in the form of temperature anisotropies, suprathermal tail extensions, and field-aligned beams. The state close to thermal equilibrium and its departure from it provides a source for spontaneous emissions of electromagnetic fluctuations, such as the whistler. Here we present a comparative analysis of the electron whistler-cyclotron and firehose fluctuations based upon anisotropic plasma modeled with Maxwellian and Tsallis-kappa-like particle distributions, to explain the correspondence relationship of the magnetic fluctuations as a function of the electron temperature and thermal anisotropy in the solar wind and magnetosphere plasmas. The analysis presented here considers correlation theory of the fluctuation-dissipation theorem and the dispersion relation of transverse fluctuations, with wave vectors parallel to the uniform background magnetic field, in a finite temperature anisotropic thermal bi-Maxwellian and nonthermal Tsallis-kappa-like magnetized electron-proton plasma. Dispersion analysis and stability thresholds are derived for these thermal and nonthermal distributions using plasma and field parameters relevant to the solar wind and magnetosphere environments. Our results indicate that there is an enhancement of the fluctuations level in the case of nonthermal distributions due to the effective higher temperature and the excess of suprathermal particles. These results suggest that a comparison of the electromagnetic fluctuations due to thermal and nonthermal distributions provides a diagnostic signature by which inferences about the nature of the particle velocity distribution function can be ascertained without in situ particle measurements.

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{(〈〉, δ E_{i} δ E_{j}^{*})}_{(ω, \overset{k}{true})}^{(s)} = 4 πi \frac{k_{B} T_{⊥ s}}{ω} Λ_{(0)}^{- 1} ((), Λ_{jm}^{- 1} χ_{mi}^{(s)} - χ_{im}^{(s) *} Λ_{mj}^{- 1 *}),

where ω is the frequency of the fluctuations,

Λ_{ij}^{- 1}

are the components of the inverse of the dispersion tensor,

Λ_{(0)}^{- 1}

Section: Theory Of Electromagnetic Fluctuations In Plasmasmentioning

confidence: 99%

Section: Theory Of Electromagnetic Fluctuations In Plasmasmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Electromagnetic fluctuations of the whistler‐cyclotron and firehose instabilities in a Maxwellian and Tsallis‐kappa‐like plasma

et al. 2015

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“…Indeed, the Tsallis formalism, which appeared as consequence of using nonadditive entropies, has the distribution function as the main element of the theory (Milovanov & Zelenyi, 2000;Tsallis, 1988Tsallis, , 2009. They have been successfully used, both observationally and theoretically (e.g., Navarro et al, 2015;Pierrard & Meyer-Vernet, 2017;Viñas et al, 2015;Yoon & Livadiotis, 2017), to describe particle distribution functions for velocity or energy (PEDF) 10.1029/2018GL078631 in a number of plasma environments, from the Earth's and other planets magnetospheres (Benson et al, 2013;Kirpichev et al, 2017;Viñas et al, 2005) to solar radio bursts (Cairns et al, 2017). They behave similar to the Maxwellian case for low and central energies but include a power law regime that operates toward higher energies, with a slope determined by the index.…”

Section: Introductionmentioning

confidence: 99%

Ion and Electron κ Distribution Functions Along the Plasma Sheet

Espinoza

Stepanova

Moya

et al. 2018

Geophysical Research Letters

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We use kappa distributions to model thousands of ion and electron flux spectra along the plasma sheet and analyze the variation of the spectral index κ and the temperature T in this region. We find that κ distributions are ubiquitous and fit well ion and electron flux spectra during quiet times, and during the expansion and recovery phases of substorms. Near Earth, and up to ∼12 RE, the κ indices are different than the rest of the plasma sheet, both for ions (κi) and electrons (κe). There is a significant dawn‐dusk asymmetry in κi toward the tail, which is enhanced during substorms. The ions also exhibit a permanent temperature asymmetry, determined by a colder dawnside. The whole tail becomes hotter during substorms, but it appears that most of the energy is deposited near Earth.

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“…where Z (ζ) is the usual plasma dispersion (or Fried & Conte) function, given below by definition (10), and…”

Section: B the Dispersion Equationmentioning

confidence: 99%

Obliquely propagating electromagnetic waves in magnetized kappa plasmas

Gaelzer

Ziebell

2016

Physics of Plasmas

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Velocity distribution functions (VDFs) that exhibit a power-law dependence on the high-energy tail have been the subject of intense research by the plasma physics community. Such functions, known as kappa or superthermal distributions, have been found to provide a better fitting to the VDFs measured by spacecraft in the solar wind. One of the problems that is being addressed on this new light is the temperature anisotropy of solar wind protons and electrons. In the literature, the general treatment for waves excited by (bi-)Maxwellian plasmas is well-established. However, for kappa distributions, the wave characteristics have been studied mostly for the limiting cases of purely parallel or perpendicular propagation, relative to the ambient magnetic field. Contributions to the general case of obliquely-propagating electromagnetic waves have been scarcely reported so far. The absence of a general treatment prevents a complete analysis of the wave-particle interaction in kappa plasmas, since some instabilities can operate simultaneously both in the parallel and oblique directions. In a recent work, Gaelzer and Ziebell [J. Geophys. Res. 119, 9334 (2014)] obtained expressions for the dielectric tensor and dispersion relations for the low-frequency, quasi-perpendicular dispersive Alfvén waves resulting from a kappa VDF. In the present work, the formalism is generalized for the general case of electrostatic and/or electromagnetic waves propagating in a kappa plasma in any frequency range and for arbitrary angles. An isotropic distribution is considered, but the methods used here can be easily applied to more general anisotropic distributions, such as the bi-kappa or product-bi-kappa.

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Magnetic Alfvén‐cyclotron fluctuations of anisotropic nonthermal plasmas

Cited by 27 publications

References 73 publications

Electromagnetic fluctuations of the whistler‐cyclotron and firehose instabilities in a Maxwellian and Tsallis‐kappa‐like plasma

Electromagnetic fluctuations of the whistler‐cyclotron and firehose instabilities in a Maxwellian and Tsallis‐kappa‐like plasma

Ion and Electron κ Distribution Functions Along the Plasma Sheet

Obliquely propagating electromagnetic waves in magnetized kappa plasmas

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