Nonlinear Growth of Firehose and Mirror Fluctuations in Astrophysical Plasmas

Schekochihin, A. A.; Cowley, S. C.; Kulsrud, Russell M.; Rosin, Mark; Heinemann, T.

doi:10.1103/physrevlett.100.081301

Cited by 104 publications

(184 citation statements)

References 27 publications

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“…[9] There is evidence that mirror modes have important effects on energetic particle diffusion [Tsurutani et al, 1999] and electron thermal conductivity [Schekochihin et al, 2008]. What is more, it has also been suggested that mirror modes observed at 1 AU might even be an indicator of the presence of ion-cyclotron waves in the solar corona [Russell et al, 2008].…”

Section: Introductionmentioning

confidence: 99%

Mirror‐mode storms inside stream interaction regions and in the ambient solar wind: A kinetic study

et al. 2013

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[1] Mirror-mode structures have been found in the solar wind at various heliocentric distances with different missions. Recently, STEREO has observed mirror-mode waves present as trains of holes and also as humps in the magnetic field magnitude. In some cases, mirror-mode trains last for very long periods of time and have been called "mirror-mode storms". We present case studies of mirror-mode storms observed in the solar wind using STEREO data in three different locations: in the downstream region of the forward shock of a stream interaction region, inside a stream interaction region far from the forward shock, and also in the ambient solar wind. To make a formal identification of the mirror mode, we determine wave characteristics using minimum variance analysis. Finally, we perform a kinetic dispersion analysis and discuss the possible origin of mirror-mode structures evaluating curves of growth for different regimes of proton temperature anisotropies in a plasma with a He component.

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Section: Introductionmentioning

confidence: 99%

Mirror‐mode storms inside stream interaction regions and in the ambient solar wind: A kinetic study

et al. 2013

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“…However, the shearing or expansion process that drove the plasma through the instability boundary in the first place, must ultimately become important again once quasilinear relaxation has pushed the system sufficiently close back to marginality. When such continued driving is accounted for, asymptotic theory [33,34] predicts secular growth of perturbations as δB/B ∝ t 1/2 up to δB/B = O(1) (cf. [35]), a very different outcome from steady-state, lowamplitude saturation.…”

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confidence: 99%

“…In this Letter, we show that weakly nonlinear mirror modes in such conditions do not saturate quasilinearly at a steady, low amplitude either, but continue to grow secularly as δB/B ∝ t 2/3 . To do this, we introduce a new asymptotic theory in the spirit of earlier theoretical work [33,34,42], in which the combined effects of weak collisionality, large-scale shearing, quasilinear relaxation [32,43,44], particle trapping [45][46][47][48] and finite ion Larmor radius (FLR) are all self-consistently retained.…”

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confidence: 99%

Non-linear mirror instability

Rincon

Schekochihin

Cowley

2014

Monthly Notices of the Royal Astronomical Society: Letters

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Slow dynamical changes in magnetic-field strength and invariance of the particles' magnetic moments generate ubiquitous pressure anisotropies in weakly collisional, magnetized astrophysical plasmas. This renders them unstable to fast, small-scale mirror and firehose instabilities, which are capable of exerting feedback on the macroscale dynamics of the system. By way of a new asymptotic theory of the early nonlinear evolution of the mirror instability in a plasma subject to slow shearing or compression, we show that the instability does not saturate quasilinearly at a steady, low-amplitude level. Instead, the trapping of particles in small-scale mirrors leads to nonlinear secular growth of magnetic perturbations, δB/B ∝ t 2/3 . Our theory explains recent collisionless simulation results, provides a prediction of the mirror evolution in weakly collisional plasmas and establishes a foundation for a theory of nonlinear mirror dynamics with trapping, valid up to δB/B = O(1).

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“…Observational evidences for fire-hose instabilities (FHI) occurring in space plasma environments have been reported 1,2 and the applications of FHI to astrophysical systems have also been proposed. 3,4 Theoretical studies of FHI have been mostly based on the kinetic theory and particle simulations [5][6][7][8][9][10][11][12] due to the issue of energy closure to the hydromagnetic equations in gyrotropic plasmas. In recent years, we have attempted to study the FHI using the so-called double-polytropic MHD and Hall MHD models and compared the results with the Vlasov theory and kinetic simulations.…”

Section: Introductionmentioning

confidence: 99%

Effects of Hall current and electron temperature anisotropy on proton fire-hose instabilities

Hau

Wang

2013

Physics of Plasmas

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The standard magnetohydrodynamic (MHD) theory predicts that the Alfvén wave may become fire-hose unstable for β∥−β⊥>2. In this study, we examine the proton fire-hose instability (FHI) based on the gyrotropic two-fluid model, which incorporates the ion inertial effects arising from the Hall current and electron temperature anisotropy but neglects the electron inertia in the generalized Ohm's law. The linear dispersion relation is derived and analyzed which in the long wavelength approximation, λik→0 or αe=μ0(p∥,e−p⊥,e)/B2=1, recovers the ideal MHD model with separate temperature for ions and electrons. Here, λi is the ion inertial length and k is the wave number. For parallel propagation, both ion cyclotron and whistler waves become propagating and growing for β∥−β⊥>2+λi2k2(αe−1)2/2. For oblique propagation, the necessary condition for FHI remains to be β∥−β⊥>2 and there exist one or two unstable fire-hose modes, which can be propagating and growing or purely growing. For large λik values, there exists no nearly parallel FHI leaving only oblique FHI and the effect of αe>1 may greatly enhance the growth rate of parallel and oblique FHI. The magnetic field polarization of FHI may be reversed due to the sign change associated with (αe−1) and the purely growing FHI may possess linear polarization while the propagating and growing FHI may possess right-handed or left-handed polarization.

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Nonlinear Growth of Firehose and Mirror Fluctuations in Astrophysical Plasmas

Cited by 104 publications

References 27 publications

Mirror‐mode storms inside stream interaction regions and in the ambient solar wind: A kinetic study

Mirror‐mode storms inside stream interaction regions and in the ambient solar wind: A kinetic study

Non-linear mirror instability

Effects of Hall current and electron temperature anisotropy on proton fire-hose instabilities

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