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Compressible magnetohydrodynamic (MHD) turbulence is ubiquitous in astrophysical phenomena ranging from the intergalactic to the stellar scales. In studying them, numerical simulations are nearly inescapable, due to the large degree of…

Fluid Dynamics · Physics 2016-07-27 Dimitar G Vlaykov , Philipp Grete , Wolfram Schmidt , Dominik R G Schleicher

Simulations of the magnetorotational instability (MRI) in a homogeneous shearing box have shown that the asymptotic strength of the magnetic field declines steeply with increasing resolution. Here I model the MRI driven dynamo as a large…

High Energy Astrophysical Phenomena · Physics 2011-02-11 Ethan T. Vishniac

While the saturated magnetic energy is independent of viscosity in dynamo experiments, it remains viscosity-dependent in state-of-the-art 3D direct numerical simulations (DNS). Extrapolating such viscous scaling-laws to realistic parameter…

Fluid Dynamics · Physics 2017-12-20 Kannabiran Seshasayanan , Basile Gallet , Alexandros Alexakis

Kinematic dynamo in incompressible isotropic turbulent flows with high magnetic Prandtl number is considered. The approach interpreting an arbitrary magnetic field distribution as a superposition of localized perturbations (blobs) is…

Fluid Dynamics · Physics 2023-10-26 A. S. Il'yn , A. V. Kopyev , V. A. Sirota , K. P. Zybin

Generation of magnetic field energy, without mean field generation, is studied. Isotropic mirror-symmetric turbulence of a conducting fluid amplifies the energy of small-scale magnetic perturbations if the magnetic Reynolds number is high,…

Astrophysics · Physics 2008-11-26 A. Gruzinov , S. Cowley , R. Sudan

Magnetic fields in galaxies are believed to be the result of dynamo amplification of initially weak seed fields, reaching equipartition strength inside the interstellar medium. The small-scale dynamo appears to be a viable mechanism to…

Astrophysics of Galaxies · Physics 2017-08-16 Michael Rieder , Romain Teyssier

In this paper, we study the development of anisotropy in strong MHD turbulence in the presence of a large scale magnetic field B 0 by analyzing the results of direct numerical simulations. Our results show that the developed anisotropy…

Plasma Physics · Physics 2017-06-14 Sita Sundar , Mahendra K. Verma , Alexandros Alexakis , Anando G. Chatterjee

We present numerical studies of 3-dimensional magnetohydrodynamic (MHD) turbulence in a strongly magnetized medium in the extremely relativistic limit, in which the inertia of the charge carriers can be neglected. We have focused on strong…

Astrophysics · Physics 2009-11-10 Jungyeon Cho

We present results from numerical simulations of nonlinear MHD dynamo action produced by three-dimensional flows that become turbulent for high values of the fluid Reynolds number. The magnitude of the forcing function driving the flow is…

Astrophysics · Physics 2009-11-07 Vasilis Archontis , Bertil Dorch , Aake Nordlund

Numerical simulations of dispersive turbulence in magnetized plasmas based on the Hall-MHD description are presented, assuming spatial variations along a unique direction making a prescribed angle with the ambient magnetic field. Main…

Earth and Planetary Astrophysics · Physics 2015-05-18 D. Laveder , L. Marradi , T. Passot , P. L. Sulem

The excitation and further sustenance of large-scale magnetic fields in rotating astrophysical systems, including planets, stars and galaxies, is generally thought to involve a fluid magnetic dynamo effect driven by helical…

Fluid Dynamics · Physics 2021-12-10 F. Rincon

Turbulence in a conducting plasma can amplify seed magnetic fields in what is known as the turbulent, or small-scale, dynamo. The associated growth rate and emergent magnetic-field geometry depend sensitively on the material properties of…

High Energy Astrophysical Phenomena · Physics 2022-10-17 Alisa K. Galishnikova , Matthew W. Kunz , Alexander A. Schekochihin

We analyse the anisotropy of homogeneous turbulence in an electrically conducting fluid submitted to a uniform magnetic field, for low magnetic Reynolds number, in the quasi- static approximation. We interpret disagreeing previous…

Fluid Dynamics · Physics 2012-07-23 B. F. N. Favier , F. S. Godeferd , C. Cambon , A. Delache , W. J. T. Bos

We numerically investigate the saturation of the hydromagnetic instabilities of a magnetized spherical Couette flow. Previous simulations [Hollerbach, 2009] demonstrated region where the axisymmetric flow, calculated from a 2-D simulation,…

Fluid Dynamics · Physics 2014-07-02 E. J. Kaplan

It is shown, that the saturated $\alpha$-effect taken from the nonlinear dynamo equations for the thin disk can still produce exponentially growing magnetic field in the case, when this field does not feed back on the $\alpha$. For negative…

Fluid Dynamics · Physics 2015-05-18 M. Reshetnyak

Magnetohydrodynamics (MHD) is invoked to address turbulent fluctuations in a variety of astrophysical systems. MHD turbulence in nature is often anisotropic and imbalanced, in that Alfvenic fluctuations moving in opposite directions along…

Astrophysics of Galaxies · Physics 2010-02-18 Jean C Perez , Stanislav Boldyrev

The presence of magnetic fields in many astrophysical objects is due to dynamo action, whereby a part of the kinetic energy is converted into magnetic energy. A turbulent dynamo that produces magnetic field structures on the same scale as…

Astrophysics of Galaxies · Physics 2020-03-19 Amit Seta , Paul J. Bushby , Anvar Shukurov , Toby S. Wood

We formulate a solvable model that describes generation and saturation of mean magnetic field in a dynamo with kinetic helicity, in the limit of large magnetic Prandtl number. This model is based on the assumption that the stochastic part…

Astrophysics · Physics 2009-11-06 Stanislav Boldyrev

A variety of studies of magnetised plasma turbulence invoke theories for the advection of a passive scalar by turbulent fluctuations. Examples include modelling the electron density fluctuations in the interstellar medium, understanding the…

Plasma Physics · Physics 2015-06-23 Joanne Mason , Stanislav Boldyrev , Fausto Cattaneo , Jean Carlos Perez

A simple model collisionless, dissipative, compressible MHD (Alfvenic) turbulence in a magnetized system is investigated. In contrast to more familiar paradigms of turbulence, dissipation arises from Landau damping, enters via nonlinearity,…

Plasma Physics · Physics 2009-10-30 M. V. Medvedev , P. H. Diamond