scholarly journals MHD Turbulence: Scaling Laws and Astrophysical Implications

2003 ◽  
pp. 56-98 ◽  
Author(s):  
Jungyeon Cho ◽  
Alex Lazarian ◽  
Ethan T. Vishniac
Keyword(s):  
Scaling Laws ◽  
Mhd Turbulence ◽  
Turbulence Scaling

Scaling laws and intermittent structures in solar wind MHD turbulence

1999 ◽  
Author(s):  
Pierluigi Veltri ◽  
André Mangeney
Keyword(s):  
Solar Wind ◽  
Scaling Laws ◽  
Mhd Turbulence

scholarly journals Coronal Heating, Weak MHD Turbulence, and Scaling Laws

2007 ◽  
Vol 657 (1) ◽  
pp. L47-L51 ◽  
Author(s):  
A. F. Rappazzo ◽  
M. Velli ◽  
G. Einaudi ◽  
R. B. Dahlburg
Keyword(s):  
Scaling Laws ◽  
Coronal Heating ◽  
Mhd Turbulence

Turbulence scaling laws and transport models

2008 ◽  
Author(s):  
X. Garbet ◽  
Sadruddin Benkadda
Keyword(s):  
Scaling Laws ◽  
Transport Models ◽  
Turbulence Scaling

scholarly journals Phenomenologies of intermittent Hall MHD turbulence

2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Mimi Dai
Keyword(s):  
Hall Effect ◽  
Scaling Laws ◽  
Structure Functions ◽  
Energy Spectra ◽  
Mhd Turbulence ◽  
Hall Mhd

<p style='text-indent:20px;'>We introduce the concept of intermittency dimension for the magnetohydrodynamics (MHD) to quantify the intermittency effect. With dependence on the intermittency dimension, we derive phenomenological laws for intermittent MHD turbulence with and without the Hall effect. In particular, scaling laws of dissipation wavenumber, energy spectra and structure functions are predicted. Moreover, we are able to provide estimates for energy spectra and structure functions which are consistent with the predicted scalings.</p>

scholarly journals Can magnetized turbulence set the mass scale of stars?

2020 ◽  
Vol 496 (4) ◽  
pp. 5072-5088 ◽  
Author(s):  
Dávid Guszejnov ◽  
Michael Y Grudić ◽  
Philip F Hopkins ◽  
Stella S R Offner ◽  
Claude-André Faucher-Giguère
Keyword(s):  
Star Formation ◽  
Scaling Laws ◽  
Initial Conditions ◽  
Mass Function ◽  
Stellar Mass ◽  
Mass Scale ◽  
Initial Mass Function ◽  
Mhd Turbulence ◽  
Numerical Resolution ◽  
Stellar Masses

ABSTRACT Understanding the evolution of self-gravitating, isothermal, magnetized gas is crucial for star formation, as these physical processes have been postulated to set the initial mass function (IMF). We present a suite of isothermal magnetohydrodynamic (MHD) simulations using the gizmo code that follow the formation of individual stars in giant molecular clouds (GMCs), spanning a range of Mach numbers found in observed GMCs ($\mathcal {M} \sim 10\!-\!50$). As in past works, the mean and median stellar masses are sensitive to numerical resolution, because they are sensitive to low-mass stars that contribute a vanishing fraction of the overall stellar mass. The mass-weighted median stellar mass M50 becomes insensitive to resolution once turbulent fragmentation is well resolved. Without imposing Larson-like scaling laws, our simulations find $M_\mathrm{50} \,\, \buildrel\propto \over \sim \,\,M_\mathrm{0} \mathcal {M}^{-3} \alpha _\mathrm{turb}\, \mathrm{SFE}^{1/3}$ for GMC mass M0, sonic Mach number $\mathcal {M}$, virial parameter αturb, and star formation efficiency SFE = M⋆/M0. This fit agrees well with previous IMF results from the ramses, orion2, and sphng codes. Although M50 has no significant dependence on the magnetic field strength at the cloud scale, MHD is necessary to prevent a fragmentation cascade that results in non-convergent stellar masses. For initial conditions and SFE similar to star-forming GMCs in our Galaxy, we predict M50 to be $\gt 20 \, \mathrm{M}_{\odot }$, an order of magnitude larger than observed ($\sim 2 \, \mathrm{M}_\odot$), together with an excess of brown dwarfs. Moreover, M50 is sensitive to initial cloud properties and evolves strongly in time within a given cloud, predicting much larger IMF variations than are observationally allowed. We conclude that physics beyond MHD turbulence and gravity are necessary ingredients for the IMF.

scholarly journals Heating of coronal loops: weak MHD turbulence and scaling laws

2007 ◽  
Author(s):  
A. F. Rappazzo ◽  
M. Velli ◽  
G. Einaudi
Keyword(s):  
Scaling Laws ◽  
Coronal Loops ◽  
Mhd Turbulence

scholarly journals New Perspectives in Turbulence: Scaling Laws, Asymptotics, and Intermittency

SIAM Review ◽  
1998 ◽  
Vol 40 (2) ◽  
pp. 265-291 ◽  
Author(s):  
G. I. Barenblatt ◽  
A. J. Chorin
Keyword(s):  
Scaling Laws ◽  
Turbulence Scaling

scholarly journals Exact scaling laws and the local structure of isotropic magnetohydrodynamic turbulence

2007 ◽  
Vol 575 ◽  
pp. 111-120 ◽  
Author(s):  
T. A. YOUSEF ◽  
F. RINCON ◽  
A. A. SCHEKOCHIHIN
Keyword(s):  
Scaling Laws ◽  
Linear Scaling ◽  
Mhd Turbulence ◽  
Third Order ◽  
Magnetohydrodynamic Turbulence ◽  
Kolmogorov Turbulence ◽  
Non Local ◽  
Prandtl Numbers ◽  
The Magnetic Field ◽  
Exact Scaling

This paper examines the consistency of the exact scaling laws for isotropic magnetohydrodynamic (MHD) turbulence in numerical simulations with large magnetic Prandtl numbers Pm and with Pm = 1. The exact laws are used to elucidate the structure of the magnetic and velocity fields. Despite the linear scaling of certain third-order correlation functions, the situation is not analogous to the case of Kolmogorov turbulence. The magnetic field is adequately described by a model of a stripy (folded) field with direction reversals at the resistive scale. At currently available resolutions, the cascade of kinetic energy is short-circuited by the direct exchange of energy between the forcing-scale motions and the stripy magnetic fields. This non-local interaction is the defining feature of isotropic MHD turbulence.

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