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Shear flows are naturally expected to occur in astrophysical environments and potential sites of continuous non-thermal Fermi-type particle acceleration. Here we investigate the efficiency of expanding relativistic outflows to facilitate…

High Energy Astrophysical Phenomena · Physics 2016-12-14 F. M. Rieger , P. Duffy

By following the Kazantsev theory and taking into account both microscopic and turbulent diffusion of magnetic fields, we develop a unified treatment of the kinematic and nonlinear stages of turbulent dynamo, and study the dynamo process…

Astrophysics of Galaxies · Physics 2016-12-28 Siyao Xu , A. Lazarian

Within the framework of shallow-water magnetohydrodynamics, we investigate the linear instability of horizontal shear flows, influenced by an aligned magnetic field and stratification. Various classical instability results, such as…

Fluid Dynamics · Physics 2016-01-15 Julian Mak , Stephen D. Griffiths , D. W. Hughes

A review of recent studies on a new mechanism of generation of large-scale magnetic field in a sheared turbulent plasma is presented. This mechanism is associated with the shear-current effect which is related to the W x J-term in the mean…

Astrophysics · Physics 2009-11-13 N. Kleeorin , I. Rogachevskii

Steady shearing and planar extension are commonly viewed as two distinct types of flow field, especially in the context of probing the rheology of complex fluids. By leveraging the kinematic equivalence between the two flows, we derive an…

Soft Condensed Matter · Physics 2026-04-14 Nicholas King , Gareth H. McKinley

Recent experiments have shown that it is possible to study a fundamental astrophysical process such as dynamo action in controlled laboratory conditions using simple MHD flows. In this paper we explore the possibility that Taylor-Couette…

Astrophysics · Physics 2009-11-07 Ashley P. Willis , Carlo F. Barenghi

We study the evolution of phase-transition-generated cosmic magnetic fields coupled to the primeval cosmic plasma in turbulent and viscous free-streaming regimes. The evolution laws for the magnetic energy density and correlation length,…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Leonardo Campanelli

In stars and planets, magnetic fields are believed to originate from the motion of electrically conducting fluids in their interior, through a process known as the dynamo mechanism. In this Letter, an optimization procedure is used to…

Fluid Dynamics · Physics 2015-03-20 Ashley P. Willis

A quasi-linear theory is presented for how randomly forced, barotropic velocity fluctuations cause an exponentially-growing, large-scale (mean) magnetic dynamo in the presence of a uniform shear flow, $\vec{U} = S x \vec{e}_y$. It is a…

Astrophysics of Galaxies · Physics 2015-05-30 James C. McWilliams

We investigate the structure of magnetic field amplified by turbulent velocity fluctuations, in the framework of the kinematic Kazantsev-Kraichnan model. We consider Kolmogorov distribution of velocity fluctuations, and assume that both…

Astrophysics · Physics 2010-01-15 Leonid Malyshkin , Stanislav Boldyrev

Determining the physical mechanisms that extract energy from turbulent fluctuations in weakly collisional magnetized plasmas is necessary for a more complete characterization of the behavior of a variety of space and astrophysical plasmas.…

Plasma Physics · Physics 2017-08-02 Kristopher G. Klein , Gregory G. Howes , Jason M. TenBarge

Natural dynamos such as planets and stars generate global scale magnetic field despite the inferred presence of small scale turbulence. Such systems are known as large scale dynamos and are typically driven by convection and influenced by…

Fluid Dynamics · Physics 2022-02-24 Ming Yan , Michael A. Calkins

We reveal and analyze an efficient magnetic dynamo action due to precession-driven hydrodynamic turbulence in the local model of a precessional flow, focusing on the kinematic stage of this dynamo. The growth rate of magnetic field…

Fluid Dynamics · Physics 2024-05-08 V. Kumar , F. Pizzi , G. Mamatsashvili , A. Giesecke , F. Stefani , A. J. Barker

We study the dynamics of magnetic fields in chiral magnetohydrodynamics, which takes into account the effects of an additional electric current related to the chiral magnetic effect in high energy plasmas. We perform direct numerical…

Plasma Physics · Physics 2022-02-15 Jennifer Schober , Igor Rogachevskii , Axel Brandenburg

We have extended our study of the competition between the drive and stabilization of plasma microinstabilities by sheared flow to include electromagnetic effects at low plasma $\beta$ (the ratio of plasma to magnetic pressure). The extended…

Plasma Physics · Physics 2015-06-16 M. D. J. Cole , S. L. Newton , S. C. Cowley , N. F. Loureiro , D. Dickinson , C. Roach , J. W. Connor

We report the first experimental observation of reversals of a dynamo field generated in a laboratory experiment based on a turbulent flow of liquid sodium. The magnetic field randomly switches between two symmetric solutions B and -B. We…

A model of soft frictionless disks in two dimensions at zero temperature is simulated with a shearing dynamics to study various kinds of asymmetries in sheared systems. We examine both single particle properties, the spatial velocity…

Soft Condensed Matter · Physics 2015-03-17 Peter Olsson

We compute statistical properties of the lowest-order multipole coefficients of the magnetic field generated by a dynamo of arbitrary shape. To this end we expand the field in a complete biorthogonal set of base functions, viz. B = sum_k…

Earth and Planetary Astrophysics · Physics 2015-05-13 P. Hoyng

We investigate numerically magnetic field generation by thermal convection with square periodicity cells in a rotating horizontal layer of electrically-conducting fluid with stress-free electrically perfectly conducting boundaries for…

Chaotic Dynamics · Physics 2010-04-12 V. Zheligovsky

We analyze the main features of granular shear flow through experimental measurements in a Couette geometry and a comparison to a locally Newtonian, continuum model of granular flow. The model is based on earlier hydrodynamic models,…

Statistical Mechanics · Physics 2021-05-26 L. Bocquet , W. Losert , D. Schalk , T. C. Lubensky , J. P. Gollub