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A theory of mechanical behaviour of the magneto-sensitive elastomers is developed in the framework of a linear elasticity approach. Using a regular rectangular lattice model, different spatial distributions of magnetic particles within a…

Soft Condensed Matter · Physics 2011-07-15 D. Ivaneyko , V. Toshchevikov , M. Saphiannikova , G. Heinrich

The inward diffusion of particles, often observed in magnetospheric plasmas (either naturally created stellar ones or laboratory devices) creates a spontaneous density gradient, which seemingly contradicts the entropy principle. We…

Plasma Physics · Physics 2015-04-28 Naoki Sato , Zensho Yoshida

The generation of solar non-axisymmetric magnetic fields is studied based on a linear alpha2-Omega dynamo model in a rotating spherical frame. The model consists of a solar-like differential rotation, a magnetic diffusivity varied with…

Astrophysics · Physics 2008-11-26 Jie Jiang , Jingxiu Wang

The effect of uniform magnetic field applied along a fixed horizontal direction in Rayleigh-B\'enard convection in low-Prandtl-number fluids has been studied using a low dimensional model. The model shows the onset of convection (primary…

Pattern Formation and Solitons · Physics 2014-02-13 Pinaki Pal , Krishna Kumar

We describe the structure of the time-harmonic electromagnetic field of a vertical Hertzian electric dipole source radiating over an infinite, translation invariant two-dimensional electron system. Our model for the electron flow takes into…

Mesoscale and Nanoscale Physics · Physics 2020-11-18 Vera Andreeva , Denis A. Bandurin , Mitchell Luskin , Dionisios Margetis

Convective dynamo simulations are performed in local Cartesian geometry. We report the first successful simulation of a large-scale oscillatory dynamo in rigidly rotating convection without stably stratified layers. A key requirement for…

Solar and Stellar Astrophysics · Physics 2015-06-19 Youhei Masada , Takayoshi Sano

The current understanding of MHD turbulence envisions turbulent eddies which are anisotropic in all three directions. In the plane perpendicular to the local mean magnetic field, this implies that such eddies become current-sheet-like…

Plasma Physics · Physics 2017-06-21 N. F. Loureiro , S. Boldyrev

We report on simulations of turbulent, rotating, stratified, magnetohydrodynamic convection in spherical wedge geometry. An initially small-scale, random, weak-amplitude magnetic field is amplified by several orders of magnitude in the…

Solar and Stellar Astrophysics · Physics 2013-11-19 Petri J. Käpylä , Maarit J. Mantere , Axel Brandenburg

The influence of the convective structure of the solar photosphere on the shifts of spectral lines of iron was studied. Line profiles in the visible and infrared spectrum were synthesized with the use of 2-D time-dependent hydrodynamic…

Solar and Stellar Astrophysics · Physics 2010-04-21 V. A. Sheminova , A. S. Gadun

We study magnetic reconnection events in a turbulent plasma within the two-fluid theory. By identifying the diffusive regions, we measure the reconnection rates as function of the conductivity and current sheet thickness. We have found that…

Plasma Physics · Physics 2017-03-06 Nicola Offeddu , Miller Mendoza

In thin ($\Delta<$ few $\lambda_i$) collisionless current sheets in a space plasma like the magnetospheric tail or magnetopause current layer, magnetic fields can grow {from thermal fluctuation level by the action of the non-magnetic Weibel…

Space Physics · Physics 2015-05-13 R. A. Treumann , R. Nakamura , W. Baumjohann

Sunspot fine structure has been modeled in the past by a combination of idealized magneto-convection simulations and simplified models that prescribe the magnetic field and flow structure to a large degree. Advancement in numerical methods…

Solar and Stellar Astrophysics · Physics 2015-05-20 Matthias Rempel

Convection and magnetic field generation in the Earth and planetary interiors are driven by both thermal and compositional gradients. In this work numerical simulations of finite-amplitude double-diffusive convection and dynamo action in…

Fluid Dynamics · Physics 2021-01-27 James F. Mather , Radostin D. Simitev

With application to inner stellar radiative zones, a linear theory is used to analyze the instability of a dipole-parity toroidal background field, in the presence of density stratification, differential rotation, and realistically small…

Solar and Stellar Astrophysics · Physics 2015-03-25 G. Ruediger , M. Schultz , L. L. Kitchatinov

Magnetic gels are composite materials, consisting of a polymer matrix and embedded magnetic particles. Those are mechanically coupled to each other, giving rise to the magnetostrictive effects as well as to a controllable overall elasticity…

Soft Condensed Matter · Physics 2023-06-21 Segun Goh , Andreas M. Menzel , René Wittmann , Hartmut Löwen

Self-sustained convective dynamos in planetary systems operate in an asymptotic regime of rapid rotation, where a balance is thought to hold between the Coriolis, pressure, buoyancy and Lorentz forces (the MAC balance). Classical numerical…

Geophysics · Physics 2018-03-30 Julien Aubert , Thomas Gastine , Alexandre Fournier

Young solar-type stars rotate rapidly and many are magnetically active; some undergo magnetic cycles similar to the 22-year solar activity cycle. We conduct simulations of dynamo action in rapidly rotating suns with the 3D MHD anelastic…

Solar and Stellar Astrophysics · Physics 2011-03-28 Benjamin P. Brown , Mark S. Miesch , Matthew K. Browning , Allen Sacha Brun , Juri Toomre

We present a realistic numerical model of sunspot and active region formation based on the emergence of flux bundles generated in a solar convective dynamo. To this end we use the magnetic and velocity fields in a horizontal layer near the…

Solar and Stellar Astrophysics · Physics 2017-09-20 Feng Chen , Matthias Rempel , Yuhong Fan

A large-scale cosmic magnetic field affects not only the growth of density perturbations, but also rotational instabilities and anisotropic deformation in the density distribution. We give a fully relativistic treatment of all these…

Astrophysics · Physics 2008-11-26 Christos Tsagas , Roy Maartens

The effects of radiative energy exchange on the convective instability of a weak field magnetic structure, which lead to a prediction and a physical explanation of the magnetic flux dependent field strength, are examined in detail using a…

Astrophysics · Physics 2007-05-23 S. Rajaguru , Siraj S. Hasan