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Related papers: A subsequentially fast dynamo on $\mathbb{T}^3$

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We report the results of three-dimensional numerical simulations of convection-driven dynamos in relatively thin rotating spherical shells that show a transition from an strong non-oscillatory dipolar magnetic field to a weaker regularly…

Fluid Dynamics · Physics 2011-02-08 R. D. Simitev , F. H. Busse , A. G. Kosovichev

Hydromagnetic dynamo theory provides the prevailing theoretical description for the origin of magnetic fields in the universe. Here we consider the problem of kinematic, small-scale dynamo action driven by a random, incompressible,…

Plasma Physics · Physics 2011-03-10 Joanne Mason , Leonid Malyshkin , Stanislav Boldyrev , Fausto Cattaneo

We study the effects of vertical outflows on mean-field dynamos in disks. These outflows could be due to thermal winds or magnetic buoyancy. We analyse numerical solutions of the nonlinear mean-field dynamo equations using a two-dimensional…

Astrophysics · Physics 2007-05-23 B. von Rekowski , W. Dobler , A. Shukurov , A. Brandenburg

(Abridged) Based on the rapidly increasing all-sky data of Faraday rotation measures and polarised synchrotron radiation, the Milky Way's magnetic field is now modelled with an unprecedented level of detail and complexity. We aim to…

Astrophysics of Galaxies · Physics 2015-06-17 Oliver Gressel , Detlef Elstner , Udo Ziegler

We report the results of a magneto-hydrodynamic (MHD) simulation of a convective dynamo in a model solar convective envelope driven by the solar radiative diffusive heat flux. The convective dynamo produces a large-scale mean magnetic field…

Solar and Stellar Astrophysics · Physics 2014-06-18 Yuhong Fan , Fang Fang

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

Recent simulations of supernova-driven turbulence within the ISM support the existence of a large-scale dynamo. With a growth time of about two hundred million years, the dynamo is quite fast -- in contradiction to many assertions in the…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-13 Detlef Elstner , Oliver Gressel , Günther Rüdiger

The amplification of magnetic fields in a highly conducting fluid is studied numerically. During growth, the magnetic field is spatially intermittent: it does not uniformly fill the volume, but is concentrated in long thin folded…

Chaotic Dynamics · Physics 2009-11-10 A. A. Schekochihin , S. C. Cowley , J. L. Maron , J. C. McWilliams

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

We consider the effect of vertical outflows on the mean-field dynamo in a thin disk. These outflows could be due to winds or magnetic buoyancy. We analyse both two-dimensional finite-difference numerical solutions of the axisymmetric dynamo…

Astrophysics · Physics 2009-10-31 A. Bardou , B. v. Rekowski , W. Dobler , A. Brandenburg , A. Shukurov

Several recent advances in turbulent dynamo theory are reviewed. High resolution simulations of small-scale and large-scale dynamo action in periodic domains are compared with each other and contrasted with similar results at low magnetic…

Solar and Stellar Astrophysics · Physics 2012-07-10 Axel Brandenburg , Dmitry Sokoloff , Kandaswamy Subramanian

We consider the kinematic dynamo equations for a passive vector in $\mathcal{M} \times \mathbb{T} \subseteq \mathbb{R}^2 \times \mathbb{T}$ describing the evolution of a magnetic field with resistivity $\varepsilon>0$, that is transported…

Analysis of PDEs · Mathematics 2025-09-24 Víctor Navarro-Fernández , David Villringer

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

Convection is one of the most important mixing processes in stellar interiors. Hydrodynamic mass entrainment can bring fresh fuel from neighboring stable layers into a convection zone, modifying the structure and evolution of the star.…

Solar and Stellar Astrophysics · Physics 2023-11-29 G. Leidi , R. Andrassy , J. Higl , P. V. F. Edelmann , F. K. Röpke

We investigate dynamo action in three-dimensional numerical simulations of turbulent spherical Couette flows. Close to the onset of dynamo action, the magnetic field exhibits an intermittent behavior, characterized by a series of short…

Fluid Dynamics · Physics 2013-04-24 Raphaël Raynaud , Emmanuel Dormy

Standard magnetohydrodynamic theories, such as the mean field dynamo theory, have been criticized when the back reaction of the magnetic field on turbulent motions is neglected. For the dynamo, this back reaction has been argued to suppress…

Astrophysics · Physics 2008-11-26 Eric G. Blackman

Main objective of this paper is to describe the dynamic transition of the incompressible MHD equations in a rectangular domain in $\mathbb{R}^{3}$. Our analysis shows that the system undergoes a first dynamic transition either to multiple…

Analysis of PDEs · Mathematics 2011-05-17 Taylan Şengül

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

Magnetic fields are a dynamically important component of the turbulent interstellar medium (ISM) of star-forming galaxies. These magnetic fields are due to a dynamo action, which is a process of converting turbulent kinetic energy to…

Astrophysics of Galaxies · Physics 2022-06-01 Amit Seta , Christoph Federrath

We consider kinematic dynamo action in rapidly rotating Boussinesq convection just above onset. The velocity is constrained to have either a square or a hexagonal pattern. For the square pattern, large-scale dynamo action is observed at…

Fluid Dynamics · Physics 2015-06-17 B. Favier , M. R. E. Proctor