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Related papers: Introduction to Field Line Helicity

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Stochasticity of magnetic field lines is important for particle transport properties. Magnetic field lines separate faster than diffusively in turbulent plasma, which is called superdiffusion. We discovered that this superdiffusion is…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Andrey Beresnyak

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

In analogy with the load and the metage in hydrodynamics, we define magnetohydrodynamic load and magnetohydrodynamic metage in the case of magnetofluids. They can be used to write the magnetic field in MHD in Clebsch's form. We show how…

Plasma Physics · Physics 2015-05-13 Sagar Chakraborty , Partha Guha

Helicity is a fundamental property of a magnetic field but to date it has only been possible to observe its evolution in one star - the Sun. In this paper we provide a simple technique for mapping the large-scale helicity density across the…

Solar and Stellar Astrophysics · Physics 2020-02-03 K. Lund , M. Jardine , L. T. Lehmann , D. H. Mackay , V. See , A. A. Vidotto , J. -F. Donati , R. Fares , C. P. Folsom , S. V. Jeffers , S. C. Marsden , J. Morin , P. Petit

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

Interaction of spin with electromagnetic field yields an effective metric along the world line of spinning particle. If we insist to preserve the usual special-relativity definitions of time and distance, critical speed which spinning…

General Physics · Physics 2015-06-03 Alexei A. Deriglazov , Walberto Guzmán Ramírez

In a density-stratified turbulent medium the cross helicity <u'.B'> is considered as a result of the interaction of the velocity fluctuations and a large-scale magnetic field. By means of a quasilinear theory and by numerical simulations we…

Solar and Stellar Astrophysics · Physics 2011-10-05 G. Rüdiger , L. L. Kitchatinov , A. Brandenburg

A two-dimensional mean field dynamo model is solved where magnetic helicity conservation is fully included. The model has a negative radial velocity gradient giving rise to equatorward migration of magnetic activity patterns. In addition…

Astrophysics · Physics 2007-05-23 A. Brandenburg , P. J. Käpylä

Previous work has introduced scale-split energy density \psi for a given vector field B in order to quantify the field stochasticity S(t). Application to turbulent magnetic fields leads to the prediction that tangling magnetic field by…

High Energy Astrophysical Phenomena · Physics 2020-02-26 Amir Jafari , Ethan Vishniac , Vignesh Vaikundaraman

We use direct numerical simulations to study the evolution, or relaxation, of magnetic configurations to an equilibrium state. We use the full single-fluid equations of motion for a magnetized, non-resistive, but viscous fluid; and a…

Astrophysics · Physics 2009-10-31 S. I. Vainshtein , Z. Mikić , R. Rosner , J. A. Linker

We study the cosmic evolution of the magnetic fields of a large sample of spiral galaxies in a cosmologically representative volume by employing a semi-analytic galaxy formation model and numerical dynamo solver in tandem. We start by…

Astrophysics of Galaxies · Physics 2019-01-03 Luiz Felippe S. Rodrigues , Luke Chamandy , Anvar Shukurov , Carlton M. Baugh , A. Russ Taylor

In the solar corona, magnetic helicity slowly and continuously accumulates in response to plasma flows tangential to the photosphere and magnetic flux emergence through it. Analyzing this transfer of magnetic helicity is key for identifying…

Solar and Stellar Astrophysics · Physics 2018-01-31 K. Dalmasse , E. Pariat , G. Valori , J. Jing , P. Démoulin

The behavior of spinning particles in the stationary homogeneous magnetic field is considered and all types of trajectories for massive and massless particles are found. It is shown that spin of particles in a magnetic field is always…

Classical Physics · Physics 2016-01-11 Alexander N. Tarakanov

Isotropic homogeneous hydromagnetic turbulence is studied using numerical simulations at resolutions of up to 1024^3 meshpoints. It is argued that, in contrast to the kinematic regime, the nonlinear regime is characterized by a spectral…

Astrophysics · Physics 2007-05-23 A. Brandenburg , N. E. L. Haugen , W. Dobler

(abridged) A detailed examination of the evolution of stochastic magnetic fields between high cosmic temperatures and the present epoch is presented. A simple analytical model matching the results of the 3D MHD simulations allows for the…

Astrophysics · Physics 2009-11-10 Robi Banerjee , Karsten Jedamzik

We study the evolution of primordial magnetic fields until the recombination epoch, which is constrained by the conservation of magnetic helicity density if they are maximally helical and by the Hosking integral if they are non-helical. We…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-07 Fumio Uchida , Motoko Fujiwara , Kohei Kamada , Jun'ichi Yokoyama

Magnetic helicity has risen to be a major player in dynamo theory, with the helicity of the small-scale field being linked to the dynamo saturation process for the large-scale field. It is a nearly conserved quantity, which allows its…

Solar and Stellar Astrophysics · Physics 2011-01-04 Alexander Hubbard , Axel Brandenburg

Based on a decomposition of the magnetic field into potential and nonpotential components, magnetic energy and relative helicity can both also be decomposed into two quantities: potential and free energies, and volume-threading and…

Solar and Stellar Astrophysics · Physics 2020-04-15 Luis Linan , Étienne Pariat , Guillaume Aulanier , Kostas Moraitis , Gherardo Valori

The origin and evolution of the magnetic helicity in the solar corona are not well understood. For instance, the magnetic helicity of an active region is often about $10^{42}$ Mx$^2$ ($10^{26}$ Wb$^{2}$), but the observed processes whereby…

Solar and Stellar Astrophysics · Physics 2009-11-13 S. Regnier

The paper address the effects of magnetic helicity conservation in a non-linear nonaxisymmetric mean-field solar dynamo model. We study the evolution of the shallow non-axisymmetric magnetic field perturbation with the strength about 10G in…

Solar and Stellar Astrophysics · Physics 2016-01-21 V. V. Pipin