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Related papers: Small-scale dynamo with nonzero correlation time

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We simulate the evolution of an initially weak magnetic field in forced turbulence for a range of Prandtl numbers. The field grows exponentially with the Kulsrud-Anderson $k^{3/2}$ spectrum until the magnetic energy approaches the…

Astrophysics · Physics 2009-09-25 Jason Maron , Steven Cowley

The existence of a dynamo effect in a simplified magnetohydrodynamic model of turbulence is considered when the magnetic Prandtl number approaches zero or infinity. The magnetic field is interacting with an incompressible…

Chaotic Dynamics · Physics 2009-11-11 Heikki Arponen , Peter Horvai

We study large-scale dynamo action due to turbulence in the presence of a linear shear flow, in the low conductivity limit. Our treatment is nonperturbative in the shear strength and makes systematic use of both the shearing coordinate…

Astrophysics of Galaxies · Physics 2015-05-14 S. Sridhar , Nishant K. Singh

Large-scale dynamo action due to turbulence in the presence of a linear shear flow is studied. Our treatment is quasilinear and kinematic but is non perturbative in the shear strength. We derive the integro-differential equation for the…

Astrophysics · Physics 2015-05-13 S. Sridhar , Kandaswamy Subramanian

We report an extensive numerical study of the small-scale turbulent dynamo at large magnetic Prandtl numbers Pm. A Pm scan is given for the model case of low-Reynolds-number turbulence. We concentrate on three topics: magnetic-energy…

Astrophysics · Physics 2008-11-26 A. A. Schekochihin , S. C. Cowley , S. F. Taylor , J. L. Maron , J. C. McWilliams

We present the results of a numerical investigation of the turbulent kinematic dynamo problem in a high Prandtl number regime. The scales of the magnetic turbulence we consider are far smaller than the Kolmogorov dissipative scale, so that…

Astrophysics · Physics 2007-05-23 R. J. West , S. Nazarenko , J. P. Laval , S. Galtier

Mechanisms of nonhelical large-scale dynamos (shear-current dynamo and effect of homogeneous kinetic helicity fluctuations with zero mean) in a homogeneous turbulence with large-scale shear are discussed. We have found that the…

Astrophysics · Physics 2009-11-13 I. Rogachevskii , N. Kleeorin

The transition to intermittent mean--field dynamos is studied using numerical simulations of isotropic magnetohydrodynamic turbulence driven by a helical flow. The low-Prandtl number regime is investigated by keeping the kinematic viscosity…

Solar and Stellar Astrophysics · Physics 2015-05-13 Erico L. Rempel , Michael R. E. Proctor , Abraham C. -L. Chian

The small-scale turbulent dynamo is an important process contributing to the cosmic magnetization. In partially ionized astrophysical plasmas, the dynamo growth of magnetic energy strongly depends on the coupling state between ions and…

Astrophysics of Galaxies · Physics 2019-02-20 Siyao Xu , Sudip K. Garain , Dinshaw S. Balsara , A. Lazarian

Nonhelical shear dynamos are studied with a particular focus on the possibility of coherent dynamo action. The primary results -- serving as a follow up to the results of Squire & Bhattacharjee [arXiv:1506.04109 (2015)] -- pertain to the…

High Energy Astrophysical Phenomena · Physics 2015-11-23 Jonathan Squire , Amitava Bhattacharjee

The small-scale turbulent dynamo is a key mechanism for amplifying galactic magnetic fields, yet the resulting field morphology remains poorly understood. Using 3D driven turbulence simulations across a range of compressibilities,…

Astrophysics of Galaxies · Physics 2026-03-25 Sasi M. Behara , Amit Seta

We study dynamo action in a convective layer of electrically-conducting, compressible fluid, rotating about the vertical axis. At the upper and lower bounding surfaces, perfectly-conducting boundary conditions are adopted for the magnetic…

Solar and Stellar Astrophysics · Physics 2011-11-23 Benjamin F. N. Favier , Paul J. Bushby

Using the magnetohydrodynamic (MHD) description, we develop a nonlinear dynamo model that couples the evolution of the large scale magnetic field with turbulent dynamics of the plasma at small scale by electromotive force (e.m.f.) in the…

Earth and Planetary Astrophysics · Physics 2011-09-29 Giuseppina Nigro , Pierlugi Veltri

Recent advances in experimental techniques have made it possible to manipulate and measure the magnetization dynamics on the femtosecond time scale which is the same order as the correlation time of the bath degrees of freedom. In the…

Mesoscale and Nanoscale Physics · Physics 2022-05-16 Hiroshi Imamura , Hiroko Arai , Rie Matsumoto , Toshiki Yamaji , Hiroshi Tsukahara

The small-scale magnetic field is ubiquitous at the solar surface---even at high latitudes. From observations we know that this field is uncorrelated (or perhaps even weakly anticorrelated) with the global sunspot cycle. Our aim is to…

Solar and Stellar Astrophysics · Physics 2016-01-11 Bidya Binay Karak , Axel Brandenburg

We study the intermittency and field-line structure of the MHD turbulence in plasmas with very large magnetic Prandtl numbers. In this regime, which is realized in the interstellar medium, some accretion disks, protogalaxies, galaxy-cluster…

Astrophysics · Physics 2008-11-26 A. Schekochihin , J. Maron , S. Cowley , J. McWilliams

We study the evolution of an inflation-generated magnetic field, due to its coupling to fluid motions, during cosmological phase transitions. We find that the magnetic field stays almost unchanged on large scales, while on small scales the…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Tina Kahniashvili , Axel Brandenburg , Leonardo Campanelli , Bharat Ratra , Alexander G. Tevzadze

We investigate the dynamo problem in the limit of small magnetic Prandtl number ($\Pm$) using a shell model of magnetohydrodynamic turbulence. The model is designed to satisfy conservation laws of total energy, cross helicity and magnetic…

Fluid Dynamics · Physics 2007-05-23 Rodion Stepanov , Franck Plunian

We perform numerical simulation of dynamo with magnetic Prandtl number $\mathrm{Pm} =0.2$ on $1024^3$ grid, and compute the energy fluxes and the shell-to-shell energy transfers. These computations indicate that the magnetic energy growth…

Fluid Dynamics · Physics 2015-06-26 Rohit Kumar , Mahendra K. Verma , Ravi Samtaney

A three-dimensional numerical computation of magnetohydrodynamic dynamo behavior is described. The dynamo is mechanically forced with a driving term of the Taylor-Green type. The magnetic field development is followed from negligibly small…

Astrophysics · Physics 2007-05-23 P. D. Mininni , Y. Ponty , D. C. Montgomery , J. -F. Pinton , H. Politano , A. Pouquet