Heating the Solar Wind by a Magnetohydrodynamic Turbulent Energy Cascade

Marino, Raffaele; Sorriso‐Valvo, L.; Carbone, V.; Noullez, A.; Bruno, R.; Bavassano, B.

doi:10.1086/587957

Cited by 139 publications

(167 citation statements)

References 21 publications

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“…The estimation of the turbulent energy transfer rate has also shown that the electromagnetic turbulence may explain the observed solar wind non-adiabatic profile of the total proton temperature (Vasquez et al 2007;Marino et al 2008;MacBride et al 2008;). However, this explanation does not take into account a possible ion temperature anisotropy, known to be important in the solar wind (see Sect.…”

Section: Energy Transfer Ratementioning

confidence: 98%

“…Solar wind energy transfer rates have been shown to lie between ∼ 0.1 kJ kg −1 s −1 (in Ulysses high latitude fast wind data, far from the Earth) and up to ∼ 10 kJ kg −1 s −1 in slow ecliptic wind at 1 AU Marino et al 2008Marino et al , 2012MacBride et al 2008;). The rate of occurrence of the linear scaling in the solar wind time series, and the corresponding energy transfer rate, have been related to several solar wind parameters.…”

Section: Energy Transfer Ratementioning

confidence: 99%

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Solar Wind Turbulence and the Role of Ion Instabilities

et al. 2013

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Solar wind is probably the best laboratory to study turbulence in astrophysical plasmas. In addition to the presence of magnetic field, the differences with neutral fluid isotropic turbulence are: (i) weakness of collisional dissipation and (ii) presence of several characteristic space and time scales. In this paper we discuss observational properties of solar wind turbulence in a large range from the MHD to the electron scales. At MHD scales, within the inertial range, turbulence cascade of magnetic fluctuations develops mostly in the plane perpendicular to the mean field, with the Kolmogorov scaling k −5/3 ⊥ for the perpendicular cascade and k −2 for the parallel one. Solar wind turbulence is compressible in nature: density fluctuations at MHD scales have the Kolmogorov spectrum. Velocity fluctuations do not follow magnetic field ones: their spectrum is a power-law with a −3/2 spectral index. Probability distribution functions of different plasma parameters are not Gaussian, indicating presence of intermittency. At the moment there is no global model taking into account all these observed properties of the inertial range. At ion scales, turbulent spectra have a break, compressibility increases and the density fluctuation spectrum has a local flattening. Around ion scales, magnetic spectra are variable and ion instabilities occur as a function of the local plasma parameters. Between ion and electron scales, a small scale turbulent cascade seems to be established. It is characterized by a well defined power-law spectrum in magnetic and density fluctuations with a spectral index close to −2.8. Approaching electron scales, the fluctuations are no more self-similar: an exponential cut-off is usually observed (for time intervals without quasi-parallel whistlers) indicating an onset of dissipation. The small scale inertial range between ion and electron scales and the electron dissipation range can be together described by ∼ k −α ⊥ exp(−k ⊥ d ), with α 8/3 and the dissipation scale d close to the electron Larmor radius d ρ e . The nature of this small scale cascade and a possible dissipation mechanism are still under debate.

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Section: Energy Transfer Ratementioning

confidence: 98%

Section: Energy Transfer Ratementioning

confidence: 99%

Solar Wind Turbulence and the Role of Ion Instabilities

et al. 2013

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“…Using the previously published analyses of Helios data, together with Advanced Composition Explorer (ACE) data, Vasquez et al [61] obtained an expression describing proton heating at 1 AU that varies with wind speed and observed temperature. More recently, these results have been extended to include high latitudes [103,104] and non-zero cross helicity (called 'imbalanced turbulence' by some) [62].…”

Section: Heatingmentioning

confidence: 99%

Third-moment descriptions of the interplanetary turbulent cascade, intermittency and back transfer

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Smith

et al. 2015

Phil. Trans. R. Soc. A.

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One contribution of 11 to a theme issue 'Dissipation and heating in solar wind turbulence' . We review some aspects of solar wind turbulence with an emphasis on the ability of the turbulence to account for the observed heating of the solar wind. Particular attention is paid to the use of structure functions in computing energy cascade rates and their general agreement with the measured thermal proton heating. We then examine the use of 1 h data samples that are comparable in length to the correlation length for the fluctuations to obtain insights into local inertial range dynamics and find evidence for intermittency in the computed energy cascade rates. When the magnetic energy dominates the kinetic energy, there is evidence of anti-correlation in the cascade of energy associated with the outward-and inward-propagating components that we can only partially explain.

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“…When the process results in a power law spectrum at small wavenumbers, with constant negative flux of some quantity that is conserved in the ideal limit, the system is said to sustain an inverse cascade of that quantity. It is a well known feature of nonlinear dynamics that has been reviewed extensively [27][28][29], in particular in the context of two dimensional (2D) Navier-Stokes fluids [30], and that has also been observed in astrophysical plasmas [31][32][33].…”

Section: Introductionmentioning

confidence: 99%

Large-scale anisotropy in stably stratified rotating flows

et al. 2014

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We present results from direct numerical simulations of the Boussinesq equations in the presence of rotation and/or stratification, both in the vertical direction. The runs are forced isotropically and randomly at small scales and have spatial resolutions of up to 1024 3 grid points and Reynolds numbers of ≈ 1000. We first show that solutions with negative energy flux and inverse cascades develop in rotating turbulence, whether or not stratification is present. However, the purely stratified case is characterized instead by an early-time, highly anisotropic transfer to large scales with almost zero net isotropic energy flux. This is consistent with previous studies that observed the development of vertically sheared horizontal winds, although only at substantially later times. However, and unlike previous works, when sufficient scale separation is allowed between the forcing scale and the domain size, the total energy displays a perpendicular (horizontal) spectrum with power law behavior compatible with ∼ k −5/3 ⊥ , including in the absence of rotation. In this latter purely stratified case, such a spectrum is the result of a direct cascade of the energy contained in the large-scale horizontal wind, as is evidenced by a strong positive flux of energy in the parallel direction at all scales including the largest resolved scales.

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Heating the Solar Wind by a Magnetohydrodynamic Turbulent Energy Cascade

Abstract: Astrophysical Journal, 677, pp. L71-L74, http://dx.doi.org./10.1086/587957International audienc

Cited by 139 publications

References 21 publications

Solar Wind Turbulence and the Role of Ion Instabilities

Solar Wind Turbulence and the Role of Ion Instabilities

Third-moment descriptions of the interplanetary turbulent cascade, intermittency and back transfer

Large-scale anisotropy in stably stratified rotating flows

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