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Related papers: The dynamo effect in decaying helical turbulence

200 papers

Investigations of the inverse cascade of magnetic helicity are conducted with pseudospectral, three-dimensional direct numerical simulations of forced and decaying incompressible magnetohydrodynamic turbulence. The high-resolution…

Solar and Stellar Astrophysics · Physics 2013-09-23 Wolf-Christian Müller , Shiva Kumar. Malapaka

We investigate hydromagnetic turbulence of primordial magnetic fields using magnetohydrodynamics (MHD) in an expanding universe. We present the basic, covariant MHD equations, find solutions for MHD waves in the early universe, and…

Astrophysics · Physics 2014-10-13 Axel Brandenburg , Kari Enqvist , Poul Olesen

We study the transition in dimensionality of a three-dimensional magnetohydrodynamic flow forced only mechanically, when the strength of a magnetic guiding field is gradually increased. We use numerical simulations to consider cases in…

Fluid Dynamics · Physics 2016-10-12 N. E. Sujovolsky , P. D. Mininni

We present evidence for finite magnetic helicity density in the heliosphere and numerical models thereof, and relate it to the magnetic field properties of the dynamo in the solar convection zone. We use simulations and solar wind data to…

Solar and Stellar Astrophysics · Physics 2012-08-03 Jörn Warnecke , Axel Brandenburg , Dhrubaditya Mitra

Two setups with interlocked magnetic flux tubes are used to study the evolution of magnetic energy and helicity on magnetohydrodynamical (MHD) systems like plasmas. In one setup the initial helicity is zero while in the other it is finite.…

Solar and Stellar Astrophysics · Physics 2011-08-24 Simon Candelaresi , Fabio Del Sordo , Axel Brandenburg

The free decay of non-helical relativistic magnetohydrodynamic turbulence is studied numerically, and found to exhibit cascading of magnetic energy toward large scales. Evolution of the magnetic energy spectrum $P_M(k,t)$ is self-similar in…

High Energy Astrophysical Phenomena · Physics 2015-06-22 Jonathan Zrake

We explain the (non)helical dynamo process using a field-structure model based on magnetic induction equation in an intuitive way. We show how nonhelical kinetic energy converts into magnetic energy and cascades toward smaller eddies in a…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-27 Kiwan Park

The question of whether a dynamo can be triggered by gravitational collapse is of great interest, especially for the early Universe. Here, we employ supercomoving coordinates to study the magnetic field amplification from decaying…

Astrophysics of Galaxies · Physics 2025-09-11 Axel Brandenburg , Evangelia Ntormousi

Observations of proxies of the magnetic helicity in the Sun over the past two solar cycles revealed reversals of the helicity hemispheric sign rule (negative in the North and positive in the South hemispheres). We apply the mean-field solar…

Solar and Stellar Astrophysics · Physics 2015-06-15 V. V. Pipin , H. Zhang , D. D. Sokoloff , K. M. Kuzanyan , Y. Gao

Aims. We investigated plasma turbulence in the context of solar wind. We concentrated on properties of ideal second-order magneto-hydrodynamic (MHD) and Hall MHD invariants. Methods. We studied the results of a two-dimensional hybrid…

Plasma Physics · Physics 2026-03-03 Petr Hellinger , Victor Montagud-Camps

We investigated a plasma system with kinematic viscosity ($\nu = 0.006$) and magnetic diffusivity ($\eta = 0.006$), driven by helical kinetic energy, to study the dynamics of energy and helicity in magnetic diffusion. Using the numerical…

Solar and Stellar Astrophysics · Physics 2024-12-20 Kiwan Park

Renormalized viscosity, renormalized resistivity, and various energy fluxes are calculated for helical magnetohydrodynamics using perturbative field theory. The calculation is to first-order in perturbation. Kinetic and magnetic helicities…

Chaotic Dynamics · Physics 2008-11-26 Mahendra K. Verma

The influence of initially given small scale magnetic energy($E_M(0)$) and helicity($H_M(0)$) on the magnetohydrodynamics(MHD) dynamo was investigated. Equations for $E_M$(t), $H_M$(t), and electromotive force($\langle {\bf v}\times {\bf…

Solar and Stellar Astrophysics · Physics 2014-04-03 Kiwan Park

Dynamos in the Sun and other bodies tend to produce magnetic fields that possess magnetic helicity of opposite sign at large and small scales, respectively. The build-up of magnetic helicity at small scales provides an important saturation…

Solar and Stellar Astrophysics · Physics 2010-11-30 Piyali Chatterjee , Gustavo Guerrero , Axel Brandenburg

Helical magnetic background fields with adjustable pitch angle are imposed on a conducting fluid in a differentially rotating cylindrical container. The small-scale kinetic and current helicities are calculated for various field geometries,…

Solar and Stellar Astrophysics · Physics 2015-05-20 M. Gellert , G. Ruediger , R. Hollerbach

Decaying magnetohydrodynamic (MHD) turbulence is important in various astrophysical contexts, including early universe magnetic fields, star formation, turbulence in galaxy clusters, magnetospheres and solar corona. Previously known in the…

High Energy Astrophysical Phenomena · Physics 2024-09-10 Shreya Dwivedi , Chandranathan Anandavijayan , Pallavi Bhat

We present the results of simulations of forced turbulence in a slab where the mean kinetic helicity has a maximum near the mid-plane, generating gradients of magnetic helicity of both large and small-scale fields. We also study systems…

Solar and Stellar Astrophysics · Physics 2010-11-30 A. Hubbard , A. Brandenburg

There is mounting evidence that the ejection of magnetic helicity from the solar surface is important for the solar dynamo. Observations suggest that in the northern hemisphere the magnetic helicity flux is negative. We propose that this…

Astrophysics · Physics 2009-11-07 A. Brandenburg , E. G. Blackman , G. R. Sarson

We derive relations for the decay of the kinetic and magnetic energies and the growth of the Taylor and integral scales in unforced, incompressible, homogeneous and isotropic three-dimensional magnetohydrodynamic (3DMHD) turbulence with…

Statistical Mechanics · Physics 2009-11-10 Chirag Kalelkar , Rahul Pandit

Dynamos wherein magnetic field is produced from velocity fluctuations are fundamental to our understanding of several astrophysical and/or laboratory phenomena. Though fluid helicity is known to play a key role in the onset of dynamo…

Plasma Physics · Physics 2023-07-05 Shishir Biswas , Rajaraman Ganesh