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In this paper we study the effects of hemispheric imbalance of magnetic helicity density on breaking the equatorial reflection symmetry of the dynamo generated large-scale magnetic field. Our study employs the axisymmetric dynamo model…

Solar and Stellar Astrophysics · Physics 2020-06-17 S. Yang , V. V. Pipin , D. D. Sokoloff , K. M. Kuzanyan , H. Zhang

Electron magnetohydrodynamic (EMHD) turbulence in two dimensions is studied via high-resolution numerical simulations with a normal diffusivity. The resulting energy spectra asymptotically approach a $k^{-5/2}$ law with increasing $R_B$,…

Plasma Physics · Physics 2009-05-01 C. J. Wareing , R. Hollerbach

Kinematic dynamo theory is presented here for turbulent conductive fluids. We describe how inhomogeneous magnetic fluctuations are generated below the viscous scale of turbulence where the spatial smoothness of the velocity permits a…

chao-dyn · Physics 2009-10-31 M. Chertkov , G. Falkovich , I. Kolokolov , M. Vergassola

The extent to which large scale magnetic fields are susceptible to turbulent diffusion is important for interpreting the need for in situ large scale dynamos in astrophysics and for observationally inferring field strengths compared to…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-18 Eric G. Blackman , Kandaswamy Subramanian

We study the nonlinear evolution of the magnetic buoyancy instability in rotating and non-rotating gas layers using numerical solutions of non-ideal, isothermal MHD equations. The unstable magnetic field is either imposed through the…

Astrophysics of Galaxies · Physics 2025-09-09 Yasin Qazi , Anvar Shukurov , Devika Tharakkal , Frederick A. Gent

We investigate numerically magnetic field generation by thermal convection with square periodicity cells in a rotating horizontal layer of electrically-conducting fluid with stress-free electrically perfectly conducting boundaries for…

Chaotic Dynamics · Physics 2010-04-12 V. Zheligovsky

We present a new analysis of the anisotropic spectral energy distribution in incompressible magnetohydrodynamic (MHD) turbulence permeated by a strong mean magnetic field. The turbulent flow is generated by high-resolution pseudo-spectral…

Plasma Physics · Physics 2015-05-19 Roland Grappin , Wolf-Christian Müller

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

We extend the standard two-scale theory of the turbulent dynamo coefficient $\alpha$ to include the nonlinear back reaction of the mean field $\bar B$ on the turbulence. We calculate the turbulent emf as a power series in $\bar B$, assuming…

Astrophysics · Physics 2009-10-31 George B. Field , Eric G. Blackman , Hongsong Chou

We present a mesoscopic approach to analyze the dynamics of a single magnetic dipole under the influence of an oscillating magnetic field, based on the formulation of a Fokker-Planck equation. The dissipated power and the viscosity of a…

Condensed Matter · Physics 2016-09-07 A. Perez Madrid , T. Alarcon , J. M. G. Vilar , J. M. Rubi

We analyze an axisymmetric magnetohydrodynamics configuration, describing the morphology of a purely differentially rotating thin plasma disk, in which linear and non-linear perturbations are triggered associated with microscopic magnetic…

Solar and Stellar Astrophysics · Physics 2018-10-02 Giovanni Montani , Mariachiara Rizzo , Nakia Carlevaro

Magnetic fields pervade the entire Universe and affect the formation and evolution of astrophysical systems from cosmological to planetary scales. The generation and dynamical amplification of extragalactic magnetic fields through cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-27 F. Rincon , F. Califano , A. A. Schekochihin , F. Valentini

Using a closure model for the evolution of magnetic correlations, we uncover an interesting plausible saturated state of the small-scale fluctuation dynamo (SSD) and a novel anology between quantum mechanical tunneling and the generation of…

Astrophysics · Physics 2007-05-23 Kandaswamy Subramanian

Large scale dynamos produce small scale current helicity as a waste product that quenches the large scale dynamo process (alpha effect). This quenching can be catastrophic (i.e.intensify with magnetic Reynolds number) unless one has fluxes…

Astrophysics · Physics 2007-05-23 Kandaswamy Subramanian , Axel Brandenburg

We have studied the large scale dynamo process forced with helical magnetic energy. The magnetically driven dynamo is not so well studied as kinetically forced dynamo. It has been thought to represent the amplification of magnetic field in…

Plasma Physics · Physics 2021-09-21 Kiwan Park , Myung-Ki Cheoun

In ideal compressible hydrodynamics there is an isomorphism between spatially one-dimensional unstea- dy and two-dimensional steady supersonic flow called piston analogy [7]. This notice shows that this is also true for non-equilibrium…

Plasma Physics · Physics 2017-04-13 Wolfgang F. Ellermeier

Kinematic dynamo in incompressible isotropic turbulent flows with high magnetic Prandtl number is considered. The approach interpreting an arbitrary magnetic field distribution as a superposition of localized perturbations (blobs) is…

Fluid Dynamics · Physics 2023-10-26 A. S. Il'yn , A. V. Kopyev , V. A. Sirota , K. P. Zybin

In this article, we consider the evolutionary model for magnetoelasticity with vanishing viscosity/damping, which is a nonlinear dispersive system. The global regularity and scattering of the evolutionary model for magnetoelasticity under…

Analysis of PDEs · Mathematics 2024-02-27 Xiaonan Hao , Jiaxi Huang , Ning Jiang , Lifeng Zhao

This paper presents scale invariant/self-similar galactic magnetic dynamo models based on the classic equations, and compares them qualitatively to recently observed magnetic fields in edge-on spiral galaxies. We classify the axially…

Astrophysics of Galaxies · Physics 2021-11-03 R. H. Henriksen , Judith Irwin

Nonlinear behaviour of galactic dynamos is studied, allowing for magnetic helicity removal by the galactic fountain flow. A suitable advection speed is estimated, and a one-dimensional mean-field dynamo model with dynamic alpha-effect is…

Astrophysics · Physics 2007-05-23 Anvar Shukurov , Dmitry Sokoloff , Kandaswamy Subramanian , Axel Brandenburg