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A rigorous theory for the generation of a large-scale magnetic field by random non-helically forced motions of a conducting fluid combined with a linear shear is presented in the analytically tractable limit of low Rm and weak shear. The…

Astrophysics · Physics 2011-12-15 T. Heinemann , J. C. McWilliams , A. A. Schekochihin

Magnetic field generation on scales large compared with the scale of the turbulent eddies is known to be possible via the so-called $\alpha$ effect when the turbulence is helical and if the domain is large enough for the $\alpha$ effect to…

Solar and Stellar Astrophysics · Physics 2013-11-18 Simon Candelaresi , Axel Brandenburg

The Sun and other cool stars harbouring outer convection zones manifest magnetic activity in their atmospheres. The connection between this activity and the properties of a deep-seated dynamo generating the magnetic flux is not well…

Solar and Stellar Astrophysics · Physics 2015-05-27 Emre Işık , Dieter Schmitt , Manfred Schüssler

We analyze magnetic kinematic dynamo in a conducting fluid where the stationary shear flow is accompanied by relatively weak random velocity fluctuations. The diffusionless and diffusion regimes are described. The growth rates of the…

Chaotic Dynamics · Physics 2015-05-20 I. Kolokolov , V. Lebedev , G. Sizov

A dynamo model is presented, based on a previously introduced kinematic model, in which the reaction of the magnetic field on the mass flow through the Lorentz force is included. Given the base mass flow corresponding to the case with no…

Solar and Stellar Astrophysics · Physics 2018-11-05 Laura Sraibman , Fernando Minotti

Direct numerical simulations are carried out to study flow structure and transport properties in turbulent Rayleigh-B\'{e}nard convection in a cylindrical cell of aspect ratio one with an imposed axial magnetic field. Flows at the Prandtl…

Fluid Dynamics · Physics 2020-06-24 Ruslan Akhmedagaev , Oleg Zikanov , Dmitry Krasnov , Joerg Schumacher

The coupled equations that describe the effect of large-scale magnetic and velocity fields on forced high-diffusivity magnetohydrodynamic flows are investigated through an extension of mean field electrodynamics. Our results generalise…

Solar and Stellar Astrophysics · Physics 2015-05-18 A. Courvoisier , D. W. Hughes , M. R. E. Proctor

Molecular dynamics simulation has been used to model pattern formation in three-dimensional Rayleigh--Benard convection at the discrete-particle level. Two examples are considered, one in which an almost perfect array of hexagonally-shaped…

Other Condensed Matter · Physics 2009-11-11 D. C. Rapaport

Combined action of helical motions of plasma (the $\alpha$ effect) and non-uniform (differential) rotation is a key dynamo mechanism of solar and galactic large-scale magnetic fields. Dynamics of magnetic helicity of small-scale fields is a…

Solar and Stellar Astrophysics · Physics 2022-09-20 N. Kleeorin , I. Rogachevskii

We present experimental evidence for a double cascade of kinetic energy in a statistically stationary rotating turbulence experiment. Turbulence is generated by a set of vertical flaps which continuously injects velocity fluctuations…

Fluid Dynamics · Physics 2021-07-27 Antoine Campagne , Basile Gallet , Frédéric Moisy , Pierre-Philippe Cortet

Rotating Rayleigh--B\'enard convection is an oft-employed model system to evaluate the interplay of buoyant forcing and Coriolis forces due to rotation, an eminently relevant interaction of dynamical effects found in many geophysical and…

Scale interactions in Hall MHD are studied using both the mean field theory derivation of transport coefficients, and direct numerical simulations in three space dimensions. In the magnetically dominated regime, the eddy resistivity is…

Plasma Physics · Physics 2009-11-11 P. D. Mininni , A. Alexakis , A. Pouquet

We study generation of magnetic fields involving large spatial scales by time- and space-periodic small-scale parity-invariant flows. The anisotropic magnetic eddy diffusivity tensor is calculated by the standard procedure involving…

Fluid Dynamics · Physics 2009-11-07 V. A. Zheligovsky , O. M. Podvigina

The small-scale turbulent dynamo is an important process contributing to the cosmic magnetization. In partially ionized astrophysical plasmas, the dynamo growth of magnetic energy strongly depends on the coupling state between ions and…

Astrophysics of Galaxies · Physics 2019-02-20 Siyao Xu , Sudip K. Garain , Dinshaw S. Balsara , A. Lazarian

We consider a two-dimensional complex plasma layer containing charged dust particles in a perpendicular magnetic field. Computer simulations of both one-component and binary systems are used to explore the equilibrium particle dynamics in…

Plasma Physics · Physics 2014-03-03 T. Ott , H. Löwen , M. Bonitz

Rayleigh-B\'enard convection, i.e. the flow of a fluid between two parallel plates that is driven by a temperature gradient, is an idealised setup to study thermal convection. Of special interest are the statistics of the turbulent…

Radiative diagnostics of high-energy density plasmas is addressed in this paper. We propose that the radiation produced by energetic particles in small-scale magnetic field turbulence, which can occur in laser-plasma experiments,…

Plasma Physics · Physics 2015-05-28 Sarah J. Reynolds , Mikhail V. Medvedev

The dynamo action achieved in the convective cores of main-sequence massive stars is explored here through 3D global simulations of convective core dynamos operating within a young $\Msun{10}$ B-type star, using the anelastic spherical…

Solar and Stellar Astrophysics · Physics 2016-10-05 Kyle C. Augustson , Allan Sacha Brun , Juri Toomre

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…

This paper presents a methodology of controlling the resonance energy exchange in mechanical system consisting of two weakly coupled magnetic pendulums interacting with the magnetic field generated by coils placed underneath. It is shown…

Systems and Control · Electrical Eng. & Systems 2023-04-20 Valery N. Pilipchuk , Krystian Polczyński , Maksymilian Bednarek , Jan Awrejcewicz