Turbulence in the interstellar medium

Falceta‐Gonçalves, D.; Kowal, Grzegorz; Falgarone, É.; Chian, Abraham C.‐L.

doi:10.5194/npg-21-587-2014

Cited by 60 publications

(35 citation statements)

References 174 publications

(170 reference statements)

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“…Both theoretical considerations and numerical simulations suggest that a shallow spectrum of the density field can arise in compressible turbulent flows. Compressibility leads to the formation of clumpy density structures, with condensations embedded in relatively diffuse regions (Beresnyak et al 2005;Kritsuk et al 2007;Kowal et al 2007;Falceta-Gonçalves et al 2014). The coupling between this density structure and local turbulent motions results in a steeper velocity power spectrum with a slope of ∼−2, but a much shallower power spectrum of the density field than the Kolmogorov −5/3 scaling for one-dimensional spectra.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

Interpretation of the Structure Function of Rotation Measure in the Interstellar Medium

Zhang

2016

ApJ

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The observed structure function (SF) of rotation measure (RM) varies as a broken power-law function of angular scales. The systematic shallowness of its spectral slope is inconsistent with the standard Kolmogorov scaling. This motivates us to examine the statistical analysis on RM fluctuations. The correlations of RM constructed by Lazarian & Pogosyan are demonstrated to be adequate in explaining the observed features of RM SFs through a direct comparison between the theoretically obtained and observationally measured SF results. By segregating the density and magnetic field fluctuations and adopting arbitrary indices for their respective power spectra, we find that when the SFs of RM and emission measure have a similar form over the same range of angular scales, the statistics of the RM fluctuations reflect the properties of density fluctuations. RM SFs can be used to evaluate the mean magnetic field along the line of sight, but cannot serve as an informative source on the properties of turbulent magnetic field in the interstellar medium. We identify the spectral break of RM SFs as the inner scale of a shallow spectrum of electron density fluctuations, which characterizes the typical size of discrete electron density structures in the observed region.

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Section: Conclusion and Discussionmentioning

confidence: 99%

Interpretation of the Structure Function of Rotation Measure in the Interstellar Medium

Zhang

2016

ApJ

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“…(1) where the energy power spectrum, E(k), is proportional to the energy input rate per mass ǫ, and the wavenumber, k (also known as the inverse length scale; k = 2π/λ), always possesses a negative power-law index of -5/3 (Falceta-Gonçalves et al 2014). However, within the astrophysical regime -such as molecular clouds -turbulence is highly supersonic and compressible and the measured energy power spectra have been shown to clearly deviate from the incompressible -5/3 value.…”

Section: Introductionmentioning

confidence: 99%

Power spectra of outflow-driven turbulence

Moraghan¹,

Kim²,

Yoon³

2015

Monthly Notices of the Royal Astronomical Society

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We investigate the power spectra of outflow-driven turbulence through high-resolution three-dimensional isothermal numerical simulations where the turbulence is driven locally in real-space by a simple spherical outflow model. The resulting turbulent flow saturates at an average Mach number of ∼ 2.5 and is analysed through density and velocity power spectra, including an investigation of the evolution of the solenoidal and compressional components. We obtain a shallow density power spectrum with a slope of ∼ −1.2 attributed to the presence of a network of localised dense filamentary structures formed by strong shock interactions. The total velocity power spectrum slope is found to be ∼ −2.0, representative of Burgers shock dominated turbulence model. The density weighted velocity power spectrum slope is measured as ∼ −1.6, slightly less than the expected Kolmogorov scaling value (slope of -5/3) found in previous works. The discrepancy may be caused by the nature of our real space driving model and we suggest there is no universal scaling law for supersonic compressible turbulence. We find that on average, solenoidal modes slightly dominate in our turbulence model as the interaction between strong curved compressible shocks generates solenoidal modes, and compressible modes decay faster.

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“…Aluie (2013) provided a theoretical MHD shockwave spectrum in the limit of infinite compressibility (Kadomtsev and Petviashvili, 1973). A recent review which examines both hydrodynamic and magnetohydrodynamic implementations of supersonic compressible turbulence on statistical quantities can be found in Falceta-Goncalves et al (2014). In this work, we follow the vast majority of investigations (Kuznetsov and Sereshchenko, 2015;Shivamoggi, 2015;Domaradzki and Carati, 2007;Sun, 2016;Westernacher-Schneider et al, 2015;Ottaviani, 1992;Qiu et al, 2016;Bershadskii, 2016) by utilizing the phenomenological description of turbulence 15 in Fourier space as well as the utilization of two-point velocity structure functions for the statistical examination of our high fidelity numerical simulations.…”

Section: Introductionmentioning

confidence: 99%

Stratified Kelvin-Helmholtz turbulence of compressible shear flows

Maulik¹,

San²

2018

Preprint

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Abstract. We study the scaling laws and structure functions of stratified shear flows by performing high-resolution numerical simulations of inviscid compressible turbulence induced by Kelvin-Helmholtz instability. An implicit large eddy simulation approach is adapted to solve our conservation laws for both two-dimensional (with a spatial resolution of 16, 3842 ) and threedimensional (with a spatial resolution of 512 3 ) configurations utilizing different compressibility characteristics such as shocks.For three-dimensional turbulence, we find that both kinetic energy and density-weighted energy spectra follow the classical 5

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Turbulence in the interstellar medium

Cited by 60 publications

References 174 publications

Interpretation of the Structure Function of Rotation Measure in the Interstellar Medium

Interpretation of the Structure Function of Rotation Measure in the Interstellar Medium

Power spectra of outflow-driven turbulence

Stratified Kelvin-Helmholtz turbulence of compressible shear flows

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