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Related papers: Growth rate degeneracies in kinematic dynamos

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We compute statistical properties of the lowest-order multipole coefficients of the magnetic field generated by a dynamo of arbitrary shape. To this end we expand the field in a complete biorthogonal set of base functions, viz. B = sum_k…

Earth and Planetary Astrophysics · Physics 2015-05-13 P. Hoyng

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 consider a 2D incompressible and electrically conducting fluid in the domain $\mathbb{T}\times\mathbb{R}$. The aim is to quantify stability properties of the Couette flow $(y,0)$ with a constant homogenous magnetic field $(\beta,0)$ when…

Analysis of PDEs · Mathematics 2023-08-25 Michele Dolce

We perform numerical experiments to study the shear dynamo problem where we look for the growth of large--scale magnetic field due to non--helical stirring at small scales in a background linear shear flow, in previously unexplored…

Astrophysics of Galaxies · Physics 2015-09-16 Nishant K. Singh , Naveen Jingade

We investigate numerically the self-sustained dynamo action in a spinning sphere whose sense of rotation reverses periodically. This system serves as a simple model of a dynamo in small bodies powered by frequent collisions. It is found…

Geophysics · Physics 2015-06-18 Xing Wei , Rainer Arlt , Andreas Tilgner

We generalize the mean field magnetic dynamo to include local evolution of the mean vorticity in addition to the mean magnetic field. The coupled equations exhibit a general mean field dynamo instability that enables the transfer of…

Astrophysics · Physics 2009-10-30 Eric G. Blackman , Tom Chou

We study the dynamo instability driven by a turbulent two dimensional flow with three components of the form (u(x, y, t), v(x, y, t), w(x, y, t)) sometimes referred to as a 2.5 dimensional flow. This type of flows provides an approximation…

Fluid Dynamics · Physics 2016-08-24 K. Seshasayanan , A. Alexakis

We investigate the Lagrangian mechanism of the kinematic ``fluctuation'' magnetic dynamo in turbulent plasma flow at small magnetic Prandtl numbers. The combined effect of turbulent advection and plasma resistivity is to carry infinitely…

Plasma Physics · Physics 2015-05-13 Gregory L. Eyink , Antonio F. Neto

We consider the evolution of an incompressible two-dimensional perfect fluid as the boundary of its domain is deformed in a prescribed fashion. The flow is taken to be initially steady, and the boundary deformation is assumed to be slow…

Analysis of PDEs · Mathematics 2007-05-23 J. Vanneste , D. Wirosoetisno

The conventional theory of small-scale magnetic field generation in a turbulent flow considers time-reversible random flows. However, real turbulent flows are known to be time irreversible: the presence of energy cascade is an intrinsic…

Fluid Dynamics · Physics 2023-12-20 A. V. Kopyev , A. S. Il'yn , V. A. Sirota , K. P. Zybin

We study fermions in a magnetic field in a finite size cylinder. With the boundary condition for the fermion flux, we show that the energy spectra and the wave-functions are modified by the finite size effect; the boundary makes the…

High Energy Physics - Phenomenology · Physics 2017-10-04 Hao-Lei Chen , Kenji Fukushima , Xu-Guang Huang , Kazuya Mameda

We present results from numerical simulations of nonlinear MHD dynamo action produced by three-dimensional flows that become turbulent for high values of the fluid Reynolds number. The magnitude of the forcing function driving the flow is…

Astrophysics · Physics 2009-11-07 Vasilis Archontis , Bertil Dorch , Aake Nordlund

We consider the generation of magnetic field by a turbulent flow. For the linear induction equation (i.e. the kinematic dynamo problem), we show that the statistical moments of the magnetic field display multiscaling and in particular…

Fluid Dynamics · Physics 2018-09-12 Kannabiran Seshasayanan , Francois Petrelis

We study mean-field dynamo action in a background linear shear flow by employing pulsed renewing flows with fixed kinetic helicity and nonzero correlation time ($\tau$). We use plane shearing waves in terms of time-dependent exact solutions…

Solar and Stellar Astrophysics · Physics 2020-05-13 Naveen Jingade , Nishant K. Singh

Recently Kleides et al [IJMPA \textbf{11}, 1697 (2008)] found a growing rate for magnetic fields in ideal plasma cosmologies by making use of general relativistic Friedmann model. This growth rate of…

General Relativity and Quantum Cosmology · Physics 2009-07-22 Garcia de Andrade

We compute numerically the threshold for dynamo action in Taylor-Green swirling flows. Kinematic calculations, for which the flow field is fixed to its time averaged profile, are compared to dynamical runs for which both the Navier-Stokes…

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

Earlier Wang et al [Phys Plasmas (2002)] have estimated a growth rate for the magnetic field of ${\gamma}=0.055$ and flow ionization velocity of $51{km}/{s}$ in a laminar plasma slow dynamo mode for aspect ratio of ${r_{0}}/L\approx{0.6}$,…

Plasma Physics · Physics 2008-10-21 Garcia de Andrade

Assuming a large-scale homogeneous magnetic field, we follow the covariant and gauge-invariant approach used by Tsagas and Barrow to describe the evolution of density and magnetic field inhomogeneities and curvature perturbations in a…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Stacey Hobbs , Peter K. S. Dunsby

It is widely accepted that astrophysical magnetic fields are generated by dynamo action. In many cases these fields exhibit organisation on a scale larger than that of the underlying turbulent flow (e.g., the eleven-year solar cycle). The…

Fluid Dynamics · Physics 2018-12-03 Laura K. Currie , Steven M. Tobias