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Using numerical methods, we systematically study in the framework of ideal MHD the effect of magnetic fields on heat transfer within a turbulent gas. We measure the rates of passive scalar diffusion within magnetized fluids and make the…

Astrophysics · Physics 2009-11-07 J. Cho , A. Lazarian , A. Honein , B. Knaepen , S. Kassinos , P. Moin

Cosmic magnetic structures have in common that they are anchored in a dynamo, that an external driver converts kinetic energy into internal magnetic energy, that this magnetic energy is transported as Poynting flux across the magnetically…

High Energy Astrophysical Phenomena · Physics 2014-03-05 Jan Kuijpers , Harald U. Frey , Lyndsay Fletcher

We reveal and analyze an efficient magnetic dynamo action due to precession-driven hydrodynamic turbulence in the local model of a precessional flow, focusing on the kinematic stage of this dynamo. The growth rate of magnetic field…

Fluid Dynamics · Physics 2024-05-08 V. Kumar , F. Pizzi , G. Mamatsashvili , A. Giesecke , F. Stefani , A. J. Barker

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

Magnetohydrodynamic (MHD) turbulence is a cross-field process relevant to many systems. A prerequisite for understanding these systems is to constrain the role of MHD turbulence, and in particular the energy exchange between kinetic and…

Fluid Dynamics · Physics 2023-04-10 R. Skalidis , K. Tassis , V. Pavlidou

We characterize and analyze rotational torsional oscillations developing in a large-eddy magnetohydrodynamical simulation of solar convection (Ghizaru, Charbonneau, and Smolarkiewicz, Astrophys. J. Lett., 715, L133 (2010); Racine et al.,…

Solar and Stellar Astrophysics · Physics 2015-06-11 P. Beaudoin , P. Charbonneau , E. Racine , P. K. Smolarkiewicz

These lecture notes and example problems are based on a course given at the University of Cambridge in Part III of the Mathematical Tripos. Fluid dynamics is involved in a very wide range of astrophysical phenomena, such as the formation…

Solar and Stellar Astrophysics · Physics 2016-05-25 Gordon I. Ogilvie

The energy dissipation of wave-like tidal flows in the convective envelope of low-mass stars is one of the key physical mechanisms that shape the orbital and rotational dynamics of short-period planetary systems. Tidal flows, and the…

In the standard theory of equilibrium tides, hydrodynamic turbulence is considered. In this paper we study the effect of magnetic fields on equilibrium tides. We find that the turbulent Ohmic dissipation associated with a tidal flow is much…

Solar and Stellar Astrophysics · Physics 2022-08-03 Xing Wei

Recent experiments have shown that floating ferromagnetic beads, under the influence of an oscillating background magnetic field, can move along a liquid-air interface in a sustained periodic locomotion [Lumay et al., Soft Matter, 2013, 9,…

These lecture notes are based on a tutorial given in 2017 at a plasma physics winter school in Les Houches. Their aim is to provide a self-contained graduate-student level introduction to the theory and modelling of the dynamo effect in…

Plasma Physics · Physics 2019-08-30 Francois Rincon

We theoretically study the motion of a magnetic domain wall induced by transverse elastic waves in a one-dimensional magnetic wire, which respects both rotational and translational symmetries. By invoking the conservation of the associated…

Mesoscale and Nanoscale Physics · Physics 2016-12-07 Se Kwon Kim , Daniel Hill , Yaroslav Tserkovnyak

Motivated by recent analytic predictions, we report numerical evidence showing that in driven incompressible magnetohydrodynamic turbulence the magnetic- and velocity-field fluctuations locally tend to align the directions of their…

Astrophysics · Physics 2007-05-23 Joanne Mason , Fausto Cattaneo , Stanislav Boldyrev

Identifying generic physical mechanisms responsible for the generation of magnetic fields and turbulence in differentially rotating flows is fundamental to understand the dynamics of astrophysical objects such as accretion disks and stars.…

Astrophysics · Physics 2009-11-13 F. Rincon , G. I. Ogilvie , M. R. E. Proctor , C. Cossu

We investigate the role of magnetic helicity in promoting cyclic magnetic activity in a global, 3D, magnetohydrodynamic (MHD) simulation of a convective dynamo. This simulation is characterized by coherent bands of toroidal field that exist…

Solar and Stellar Astrophysics · Physics 2016-06-15 Mark S. Miesch , Mei Zhang , Kyle C. Augustson

We consider the dynamics of a layer of an incompressible electrically conducting fluid interacting with the magnetic field in a two-dimensional horizontally periodic setting. The upper boundary is in contact with the atmosphere, and the…

Analysis of PDEs · Mathematics 2021-01-13 Yanjin Wang , Zhouping Xin

Using results of laboratory experiments, direct numerical simulations, geomagnetic and solar observations, it is shown that high moments of helicity distribution can dominate power spectra of the magnetic field generated by the…

Fluid Dynamics · Physics 2021-12-30 A. Bershadskii

The non-modal self-heating mechanism driven by the velocity shear in kinematically complex magnetohydrodynamic (MHD) plasma flows is considered. The study is based on the full set of MHD equations including dissipative terms. The equations…

Solar and Stellar Astrophysics · Physics 2015-06-12 Zaza Osmanov , Andria Rogava , Stefaan Poedts

The possibility of the existence of quasi-stationary electromagnetic fields in plasma supported by their own self-consistent current follows from Maxwell's equations with field sources. These equations also give rise to a wave equation for…

Classical Physics · Physics 2023-01-02 Yurii A. Spirichev

Mean-field dynamo theory has important applications in solar physics and galactic magnetism. We discuss some of the many turbulence effects relevant to the generation of large-scale magnetic fields in the solar convection zone. The…

Solar and Stellar Astrophysics · Physics 2023-11-23 Axel Brandenburg , Detlef Elstner , Youhei Masada , Valery Pipin