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Related papers: Helical ${\alpha}$-dynamos as twisted magnetic flu…

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The inverse cascade of magnetic energy occurs when helicity or rotational instability exists in the magnetohydrodynamic (MHD) system. This well known phenomenon has been considered as a basis for the large scale magnetic field in universe.…

Plasma Physics · Physics 2016-02-16 Kiwan Park

Two theorems on the Riemannian geometrical constraints on vortex magnetic filaments acting as dynamos in (MHD) flows are presented. The use of Gauss-Mainard-Codazzi equations allows us to investigate in detail the influence of curvature and…

Astrophysics · Physics 2007-05-23 L. C. Garcia de Andrade

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 discuss some aspects of magnetic reconnection which could help in understanding many aspects of magnetic plasma interactions. We will show that the helical structure often observed in polar jets is a natural consequence of magnetic…

Solar and Stellar Astrophysics · Physics 2015-05-27 Ehsan Tavabi , Serge Koutchmy , Ali Ajabshirizadeh

The dynamics of magnetic field decay with Hall drift is investigated. Assuming that axisymmetric magnetic fields are located in a spherical crust with uniform conductivity and electron number density, long-term evolution is calculated up to…

High Energy Astrophysical Phenomena · Physics 2015-06-03 Yasufumi Kojima , Shota Kisaka

A strong toroidal field can exist in form of a magnetic layer in the overshoot region below the solar convection zone. This motivates a more detailed study of the magnetic buoyancy instability with rotation. We calculate the alpha effect…

Solar and Stellar Astrophysics · Physics 2011-10-04 Piyali Chatterjee , Dhrubaditya Mitra , Matthias Rheinhardt , Axel Brandenburg

To find out whether toroidal field can stably exist in galaxies the current-driven instability of toroidal magnetic fields is considered under the influence of an axial magnetic field component and under the influence of both rigid and…

Astrophysics of Galaxies · Physics 2015-05-19 G. Ruediger , M. Schultz , D. Elstner

The buoyant transport of magnetic fields from the solar interior towards the surface plays an important role in the emergence of active regions, the formation of sunspots and the overall solar dynamo. Observations suggest that toroidal flux…

Solar and Stellar Astrophysics · Physics 2018-06-27 Bhishek Manek , Nicholas Brummell , Dongwook Lee

An effective one-dimensional Schr\"odinger equation for a spinless particle constrained to motion near a toroidal helix immersed in an arbitrarily oriented constant magnetic field is developed. The dependence of the induced toroidal moments…

Quantum Physics · Physics 2011-08-26 J. Williamson , M. Encinosa

The alpha effect is known to be an indispensable energy source of the poloidal magnetic field in the sun or planet. However, the alpha effect is quenched as the magnetic field grows due to the conservation of magnetic helicity. With these…

Solar and Stellar Astrophysics · Physics 2020-08-05 Kiwan Park

Various approaches to estimate turbulent transport coefficients from numerical simulations of hydromagnetic turbulence are discussed. A quantitative comparison between the averaged magnetic field obtained from a specific three-dimensional…

Astrophysics · Physics 2009-11-07 Axel Brandenburg , Dmitry Sokoloff

In our previous work [J. Chem. Phys. \textbf{136}, 024502 (2012)], we reported a demixing phase transition of a two-dimensional, binary Heisenberg fluid mixture driven by the ferromagnetic interactions of the magnetic species. Here, we…

Soft Condensed Matter · Physics 2015-06-16 Ken Lichtner , Sabine H. L. Klapp

A 3D simulation of a non-relativistic, magnetically driven jet propagating in a stratified atmosphere is presented, covering about three decades in distance and two decades in sideways expansion. The simulation captures the jet acceleration…

High Energy Astrophysical Phenomena · Physics 2015-05-13 R. Moll

We perform direct numerical simulations of the equations of magnetohydrodynamics with external random forcing and in the presence of gravity. The domain is divided into two parts: a lower layer where the forcing is helical and an upper…

Solar and Stellar Astrophysics · Physics 2014-10-20 Dhrubaditya Mitra , A. Brandenburg , N. Kleeorin , I. Rogachevskii

Estimates for the nonlinear alpha effect in helical turbulence with an applied magnetic field are presented using two different approaches: the imposed-field method where the electromotive force owing to the applied field is used, and the…

Solar and Stellar Astrophysics · Physics 2009-11-13 A. Hubbard , F. Del Sordo , P. J. Käpylä , A. Brandenburg

Two examples of the use of differential geometry in plasma physics are given: The first is the computation and solution of the constraint equations obtained from the Riemann metric isometry of the twisted flux tube. In this case a…

Astrophysics · Physics 2007-05-23 Garcia de Andrade

We study the evolution of primordial magnetic fields in an expanding cosmic plasma. For this purpose we present a comprehensive theoretical model to consider the evolution of MHD turbulence that can be used over a wide range of physical…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-12 Tina Kahniashvili , Axel Brandenburg , Alexander G. Tevzadze

We investigate the transport coefficients $\alpha$ and $\beta$ in plasma systems with varying Reynolds numbers while maintaining a unit magnetic Prandtl number. {The $\alpha$ and $\beta$ tensors parameterize the turbulent electromotive…

Plasma Physics · Physics 2025-06-27 Kiwan Park

The backreaction of the Lorentz force on the alpha-effect is studied in the limit of small magnetic and fluid Reynolds numbers, using the first order smoothing approximation (FOSA) to solve both the induction and momentum equations. Both…

Astrophysics · Physics 2008-11-26 Sharanya Sur , Kandaswamy Subramanian , Axel Brandenburg

We investigate magnetic field amplification in a turbulent velocity field with nonzero helicity, in the framework of the kinematic Kazantsev-Kraichnan model. We present the numerical solution of the model for the practically important case…

Astrophysics · Physics 2010-11-11 Leonid Malyshkin , Stanislav Boldyrev