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Using a rotating flat layer heated from below as an example, we consider effects which lead to stabilizing an exponentially growing magnetic field in magnetostrophic convection in transition from the kinematic dynamo to the full non-linear…

Fluid Dynamics · Physics 2015-05-18 P. Hejda , M. Reshetnyak

The turbulent dynamo may explain the origin of cosmic magnetism. While the exponential amplification of magnetic fields has been studied for incompressible gases, little is known about dynamo action in highly-compressible, supersonic…

Astrophysics of Galaxies · Physics 2014-12-05 Christoph Federrath , Jennifer Schober , Stefano Bovino , Dominik R. G. Schleicher

Helicity and \alpha effect driven by the nonaxisymmetric Tayler instability of toroidal magnetic fields in stellar radiation zones are computed. In the linear approximation a purely toroidal field always excites pairs of modes with…

Solar and Stellar Astrophysics · Physics 2015-05-28 G. Ruediger , L. L. Kitchatinov , D. Elstner

Our attention focuses on the stochastic dynamo equation with non-normal operator that give an insight into the role of stochastics and non-normality in the galactic magnetic field generation. The main point of this Letter is a discussion of…

Astrophysics · Physics 2009-11-07 Sergei Fedotov

The thin-disc global asymptotics are discussed for axisymmetric mean-field dynamos with vacuum boundary conditions allowing for non-local terms arising from a finite radial component of the mean magnetic field at the disc surface. This…

Astrophysics · Physics 2009-11-10 Ashley P. Willis , Anvar Shukurov , Andrew Soward , Dmitry Sokoloff

We use three-dimensional magnetohydrodynamical (MHD) simulations to study the formation of a corona above an initially weakly magnetized, isothermal accretion disk. We also describe a modification to time-explicit numerical algorithms for…

Astrophysics · Physics 2009-10-31 K. A. Miller , J. M. Stone

The ordered magnetic field observed via polarized synchrotron emission in nearby disc galaxies can be explained by a mean-field dynamo operating in the diffuse interstellar medium (ISM). Additionally, vertical-flux initial conditions are…

Astrophysics of Galaxies · Physics 2016-01-06 A. Bendre , O. Gressel , D. Elstner

We present a three-dimensional model of rotating convection combined with a simplified corona in spherical coordinates. The motions in the convection zone generate a large-scale magnetic field that gets sporadically ejected into the outer…

Solar and Stellar Astrophysics · Physics 2012-07-17 Jörn Warnecke , Petri J. Käpylä , Maarit. J. Mantere , Axel Brandenburg

Self-organization properties of sustained magnetized plasma are applied to selected solar data to understand solar magnetic fields. Torsional oscillations are speed-up and slow-down bands of the azimuthal flow that correlate with the solar…

Solar and Stellar Astrophysics · Physics 2018-07-26 T. R. Jarboe , T. E. Benedett , C. J. Everson , C. J. Hansen , A. C. Hossack , K. D. Morgan , B. A. Nelson , J. M. Penna , D. A. Sutherland

The exploration of mean-field galactic dynamos affected by a galactic spiral pattern, begun in Chamandy et al. (2013, hereafter Paper I) with numerical simulations, is continued here with an asymptotic solution. The mean-field dynamo model…

Astrophysics of Galaxies · Physics 2015-06-12 Luke Chamandy , Kandaswamy Subramanian , Anvar Shukurov

We examine the behaviour of an axisymmetric galactic dynamo model with a radial accretion flow in the disc. We also introduce a vertical magnetic flux through the galactic midplane, to simulate the presence of a large scale magnetic field…

Astrophysics · Physics 2009-10-31 David Moss , Anvar Shukurov

Using recent results on the operation of turbulent dynamos, we show that a turbulent dynamo can amplify a large scale magnetic field in the envelopes of asymptotic giant branch (AGB) stars. We propose that a slow rotation of the AGB…

Astrophysics · Physics 2009-11-06 Noam Soker , Essam Zoabi

Large-scale magnetic field is believed to play a key role in launching and collimating jets/outflows. It was found that advection of external field by a geometrically thin disk is rather inefficient, while the external weak field may be…

High Energy Astrophysical Phenomena · Physics 2021-03-24 Jia-wen Li , Xinwu Cao

The amplification of magnetic fields is crucial for understanding the observed magnetization of stars and galaxies. Turbulent dynamo is the primary mechanism responsible for that but the understanding of its action in a collapsing…

Astrophysics of Galaxies · Physics 2026-04-22 Muhammed Irshad P , Pallavi Bhat , Kandaswamy Subramanian , Anvar Shukurov

Numerical MHD simulations play increasingly important role for understanding mechanisms of stellar magnetism. We present simulations of convection and dynamos in density-stratified rotating spherical fluid shells. We employ a new 3D…

Solar and Stellar Astrophysics · Physics 2015-09-03 Radostin D. Simitev , Alexander G. Kosovichev , Friedrich H. Busse

Helical turbulence is thought to provide the key to the generation of large-scale magnetic fields. Turbulence also generically leads to rapidly growing small-scale magnetic fields correlated on the turbulence scales. These two processes are…

Astrophysics · Physics 2008-11-26 Kandaswamy Subramanian

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

Two of the most widely observed and yet most puzzling features of the Sun's magnetic field are coronal loops that are smooth and laminar and prominences/filaments that are strongly sheared. These two features would seem to be quite…

Solar and Stellar Astrophysics · Physics 2017-01-25 Kalman J. Knizhnik , Spiro K. Antiochos , C. Richard DeVore

We study the connection between spherical wedge and full spherical shell geometries using simple mean-field $\alpha^2$ dynamos. We solve the equations for a one-dimensional time-dependent mean-field dynamo to examine the effects of varying…

Solar and Stellar Astrophysics · Physics 2016-10-05 E. Cole , A. Brandenburg , P. J. Käpylä , M. J. Käpylä

Supernovae are known to be the dominant energy source for driving turbulence in the interstellar medium. Yet, their effect on magnetic field amplification in spiral galaxies is still poorly understood. Previous analytical models, based on…

Astrophysics · Physics 2009-11-13 Oliver Gressel , Detlef Elstner , Udo Ziegler , Günther Rüdiger
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