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Related papers: Cylindrical anisotropic $\alpha^{2}$ dynamos

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We provide a theory of dynamo ($\alpha$ effect) and momentum transport in three-dimensional magnetohydrodynamics. For the first time, we show that the $\alpha$ effect is severely reduced by the shear even in the absence of magnetic field.…

Fluid Dynamics · Physics 2008-06-12 Nicolas Leprovost , Eun-Jin Kim

Magnetic helicity fluxes in turbulently driven alpha^2 dynamos are studied to demonstrate their ability to alleviate catastrophic quenching. A one-dimensional mean-field formalism is used to achieve magnetic Reynolds numbers of the order of…

Solar and Stellar Astrophysics · Physics 2012-07-17 Simon Candelaresi , Axel Brandenburg

Mars Global Surveyor measurements revealed that the Martian crust is strongly magnetized in the southern hemisphere while the northern hemisphere is virtually void of magnetization. Two possible reasons have been suggested for this…

Earth and Planetary Astrophysics · Physics 2014-02-04 Wieland Dietrich , Johannes Wicht

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

To study the onset of a stationary dynamo in the presence of inner or outer walls of various electromagnetic properties, we propose a simple 1D-model in which the flow is replaced by an alpha effect. The equation of dispersion of the…

Fluid Dynamics · Physics 2009-05-07 R. Avalos-Zuniga , F. Plunian

Magnetic dynamo action caused by the magnetorotational instability is studied in the shearing-box approximation with no imposed net magnetic flux. Consistent with recent studies, the dynamo action is found to be sensitive to the aspect…

Solar and Stellar Astrophysics · Physics 2017-04-28 Justin Walker , Stanislav Boldyrev

The consequences of the shear-induced alpha effect to the long-term modulation of magnetic activity are examined with the help of the axisymmetric numerical dynamo model that includes the self-consistent description of the angular momentum…

Astrophysics · Physics 2007-12-18 V. V. Pipin

In this work, dynamics of chiral domain walls in long and narrow magnetic heterostructures based on non-centrosymmetric chiral magnets with bulk Dzyaloshinskii-Moriya interactions (DMI) and perpendicular magnetic anisotropy is…

Mesoscale and Nanoscale Physics · Physics 2022-02-02 Mei Li , Bin Xi , Jie Lu , Yongjun Liu

Kinney et al [PPL \textbf{1},(1994)] have investigated plasma filamentary structure dynamics. More recently, Wilkin et al [Phys Rev Lett \textbf{99}:134501,(2007)] have shown that kinetic energy spectrum of magnetic structures in…

Plasma Physics · Physics 2009-06-08 Garcia de Andrade

The paper presents a study of a solar dynamo model operating in the bulk of the convection zone with the toroidal magnetic field flux concentrated in the subsurface rotational shear layer. We explore how this type of dynamo may depend on…

Solar and Stellar Astrophysics · Physics 2015-05-28 V. V. Pipin , A. G. Kosovichev

For a simple spherically symmetric mean-field dynamo model we investigate the possibility of determining the radial dependence of the coefficient $\alpha$. Growth rates for different magnetic field modes are assumed to be known by…

Astrophysics · Physics 2009-05-20 Frank Stefani , Gunter Gerbeth

We analyze the effects of the background velocity and the initial magnetic field correlations, and viscosities on the turbulent dynamo and the \alpha-effect. We calculate the \alpha-coefficients for arbitrary magnetic and fluid viscosities,…

Statistical Mechanics · Physics 2009-11-10 Abhik Basu

Anisotropic antiferromagnetic systems of dimensionality greater than one in an external field are shown to exhibit a complicated array of ground states depending on the spin structure of the surface. The simplest structure that exhibits…

Materials Science · Physics 2009-11-10 B. A. Ivanov , C. E. Zaspel , A. Yu. Merkulov

The relative importance of the helicity and cross-helicity electromotive dynamo effects for self-sustained magnetic field generation by chaotic thermal convection in rotating spherical shells is investigated as a function of shell…

Fluid Dynamics · Physics 2020-12-18 Luis Silva , Parag Gupta , David MacTaggart , Radostin D. Simitev

The irregular polarity reversals of the Earth's magnetic field have attracted much interest during the last decades. Despite the fact that recent numerical simulations of the geodynamo have shown nice polarity transitions, the very reason…

Geophysics · Physics 2007-05-23 F. Stefani , G. Gerbeth , U. Guenther

An effect of rotation on a developed turbulent stratified convection is studied. Dependencies of the hydrodynamic helicity, the alpha-tensor and the effective drift velocity of the mean magnetic field on the rate of rotation and an…

Astrophysics · Physics 2009-11-07 N. Kleeorin , I. Rogachevskii

We analyze the nature of dynamo action that produces horizontally averaged magnetic fields in two particular flows that were studied by Roberts (1972, Phil. Trans. R. Soc. A 271, 411), namely his flows II and III. They have zero kinetic…

Solar and Stellar Astrophysics · Physics 2014-04-25 Matthias Rheinhardt , Ebru Devlen , Karl-Heinz Rädler , Axel Brandenburg

We use three-dimensional direct numerical simulations of the helically forced magnetohydrodynamic equations in spherical shell segments in order to study the effects of changes in the geometrical shape and size of the domain on the growth…

Astrophysics · Physics 2010-01-15 Dhrubaditya Mitra , Reza Tavakol , Axel Brandenburg , David Moss

We present numerical results on dynamo action in a flow driven by an azimuthal body force localized near the end of an elongated cylindrical container. The analysis focuses on the central region of the cylinder, where axial variations in…

Geophysics · Physics 2026-02-19 I. Grants , J. Priede

The homogeneous dynamo effect is at the root of cosmic magnetic field generation. With only a very few exceptions, the numerical treatment of homogeneous dynamos is carried out in the framework of the differential equation approach. The…

Astrophysics · Physics 2009-11-10 Mingtian Xu , Frank Stefani , Gunter Gerbeth