Electromagnetic proton cyclotron instability: Proton velocity distributions

Gary, S. Peter; Vazquez, Victor Manuel; Winske, D.

doi:10.1029/96ja00295

Cited by 19 publications

(13 citation statements)

References 18 publications

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“…Needless to say, the assumption of the bi‐Maxwellian model is in general not expected to be valid in a strict sense, when the instability distorts the velocity space as a result of wave‐particle interaction. For instance, the hybrid simulation of the proton cyclotron instability by Gary et al [1996b] and the similar hybrid simulation of the parallel firehose instability by Matteini et al [2006]show that the proton distribution in the nonlinear stage of the instability development significantly deviates from the bi‐Maxwellian form. However, since the anisotropy‐driven proton cyclotron and parallel firehose instabilities are known to involve a broad resonant velocity space, such that the bulk of the ion population participates in the wave‐particle resonant interaction process, these instabilities are essentially driven by the bulk properties such as the temperature anisotropy, i.e., velocity moments, of the plasma, and do not depend too sensitively on the details of the velocity space distribution function.…”

Section: Quasilinear Theory Of Proton Cyclotron Anisotropy/β Inverse mentioning

confidence: 99%

Quasilinear theory of anisotropy‐beta relations for proton cyclotron and parallel firehose instabilities

Seough¹,

Yoon²

2012

J. Geophys. Res.

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[1] The solar wind and the Earth's magnetosheath frequently possess proton temperature anisotropies that violate the predictions of adiabatic fluid theory. In the literature, various threshold conditions expressed as inverse correlations between the proton anisotropy, T ? /T k , and parallel beta, b k , have been constructed on the basis of linear stability analysis for anisotropy-driven instabilities, hybrid simulations, or by simply fitting the observations. For T ? /T k > 1, proton cyclotron and mirror instabilities are operative, while for T k > T ? , parallel and oblique firehose instabilities can be taken into account in the construction of the inverse correlation. In the present paper, quasilinear kinetic theory of parallel proton cyclotron and firehose instabilities are employed to self-consistently construct the T ? /T k vs b k threshold conditions. In principle, such an approach eliminates the necessity for empirical models of inverse correlations, since inverse correlations should naturally emerge as the time-asymptotic states of quasilinear processes. It is found that the self-consistent threshold conditions constructed on the basis of quasilinear formalism compare reasonably well with available models, thus confirming that quasilinear method is a reasonable approach.Citation: Seough, J., and P. H. Yoon (2012), Quasilinear theory of anisotropy-beta relations for proton cyclotron and parallel firehose instabilities,

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Section: Quasilinear Theory Of Proton Cyclotron Anisotropy/β Inverse mentioning

confidence: 99%

Quasilinear theory of anisotropy‐beta relations for proton cyclotron and parallel firehose instabilities

Seough¹,

Yoon²

2012

J. Geophys. Res.

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“…This is obviously an approximation, as more rigorous simulations such as those by Gary et al (1996), Matteini et al (2006), Hellinger et al (2014), etc., depict some deviations of the particle distributions in the nonlinear stage of instability progression. This is obviously an approximation, as more rigorous simulations such as those by Gary et al (1996), Matteini et al (2006), Hellinger et al (2014), etc., depict some deviations of the particle distributions in the nonlinear stage of instability progression.…”

Section: Macroscopic Kinetic Model Of the Solar Wind Bulk Parametersmentioning

confidence: 99%

Combined Whistler Heat Flux and Anisotropy Instabilities in Solar Wind

Sarfraz

Yoon

2020

JGR Space Physics

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Whistler heat flux and electron temperature anisotropy instabilities are spontaneously generated in the expanding solar wind. The present study investigates the interplay between the two unstable modes and how each contributes to the dynamical evolution of macroscopic quantities. Whistler heat flux instability is excited in the forward direction along the heat flow, whereas anisotropy instability propagates in both backward and forward directions. Velocity moment-based quasi-linear theory is employed in order to investigate the saturation behavior of these instabilities, and it is shown that under certain conditions, the forward propagating whistler heat flux instability dominates, while for other conditions, especially when the temperature anisotropies are sufficiently high, it is shown that the backward mode may also contribute to the dynamical process, and even dominate. These saturation behaviors cannot be predicted by linear growth rate alone and that they imply that in the global-kinetic models of the solar wind, bidirectional nature of these instabilities must be carefully taken into account.

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“…As an example, we consider the first case presented by Gary et al [4], which simulated the evolution of an electron-proton plasma with an initial proton bi-Maxwellian distribution of β ||p = 0.5 and T ⊥p /T ||p = 2.94.…”

Section: Examplementioning

confidence: 99%

“…This anisotropy instability has been investigated in detail by Gary and co-workers, primarily through the use of hybrid simulations [1][2][3][4][5][6]. This anisotropy instability has been investigated in detail by Gary and co-workers, primarily through the use of hybrid simulations [1][2][3][4][5][6].…”

Section: Introduction Resonant Cyclotron Interactionmentioning

confidence: 99%

A Kinetic Shell Description of the Ion Cyclotron Anisotropy Instability

Isenberg¹

2003

AIP Conference Proceedings

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Comparison of solar wind driving mechanisms: ion cyclotron resonance versus kinetic suprathermal electron effects AIP Conf.Abstract. We consider the simulation investigations of the electromagnetic ion cyclotron anisotropy instability which have been undertaken by Gary and co-workers, in particular their claim that an unstable bi-Maxwellian ion distribution will retain its bi-Maxwellian character when it reaches the asymptotic stable state. Quasilinear theory predicts that the time-asymptotic ion distribution will be given by a form of the kinetic shell distribution, with no density gradients along surfaces of constant energy in the wave frame. These constant energy surfaces are not ellipses, as would be required for contours of a bi-Maxwellian distribution. We derive an expression for this asymptotic distribution predicted by quasilinear theory. We then present an example, and compare it with a published simulation result by Gary et al. We find some aspects of our results in agreement with the simulation, but discrepancies appear at small v || . Further comparative studies could provide useful information on the applicability of quasilinear theory and/or hybrid simulations to wave-particle interactions in space plasmas.

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Electromagnetic proton cyclotron instability: Proton velocity distributions

Cited by 19 publications

References 18 publications

Quasilinear theory of anisotropy‐beta relations for proton cyclotron and parallel firehose instabilities

Quasilinear theory of anisotropy‐beta relations for proton cyclotron and parallel firehose instabilities

Combined Whistler Heat Flux and Anisotropy Instabilities in Solar Wind

A Kinetic Shell Description of the Ion Cyclotron Anisotropy Instability

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