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We perform cosmological, hydrodynamic simulations of magnetic fields in galaxy clusters. The computational code combines the special-purpose hardware Grape for calculating gravitational interaction, and smooth-particle hydrodynamics for the…

Astrophysics · Physics 2007-05-23 Klaus Dolag , Matthias Bartelmann , Harald Lesch

We report a novel singularity in the hysteresis of spin glasses, the reversal-field memory effect, which creates a non-analyticity in the magnetization curves at a particular point related to the history of the sample. The origin of the…

Disordered Systems and Neural Networks · Physics 2007-05-23 H. G. Katzgraber , F. Pazmandi , C. R. Pike , Kai Liu , R. T. Scalettar , K. L. Verosub , G. T. Zimanyi

We perform cosmological, hydrodynamic simulations of magnetic fields in galaxy clusters. The computational code combines the special-purpose hardware Grape for calculating gravitational interaction, and smooth-particle hydrodynamics for the…

Astrophysics · Physics 2007-05-23 Klaus Dolag , Matthias Bartelmann , Harald Lesch

Magnetic helicity plays a tremendously important role when it is different from zero on average. Most notably, it leads to the phenomenon of an inverse cascade. Here, we consider decaying magnetohydrodynamic (MHD) turbulence as well as some…

Plasma Physics · Physics 2023-05-29 Axel Brandenburg , Gustav Larsson

The dynamics of magnetic moments consist of a precession around the magnetic field direction and a relaxation towards the field to minimize the energy. While the magnetic moment and the angular momentum are conventionally assumed to be…

Other Condensed Matter · Physics 2023-06-14 Ritwik Mondal , Levente Rózsa , Michael Farle , Peter M. Oppeneer , Ulrich Nowak , Mikhail Cherkasskii

Magnetization reversal in permanent magnets occurs by the nucleation and expansion of reversed domains. Micromagnetic theory offers the possibility to localize the spots within the complex structure of the magnet where magnetization…

Materials Science · Physics 2018-05-25 J. Fischbacher , A. Kovacs , L. Exl J. Kühnel , E. Mehofer , H. Sepehri-Amin , T. Ohkubo , K. Hono , T. Schrefl

For understanding magnetic effects on dynamical tides, we study the rotating magneto-hydrodynamic (MHD) flow driven by harmonic forcing. The linear responses are analytically derived in a periodic box under the local WKB approximation. Both…

Solar and Stellar Astrophysics · Physics 2016-08-31 Xing Wei

A model is introduced for the theoretical description of nanoscale magnetic films with high perpendicular anisotropy. In the model the magnetic film is described in terms of single domain magnetic grains, interacting via exchange as well as…

Condensed Matter · Physics 2009-10-28 U. Nowak

We solve the equations of motion of a one-dimensional planar Heisenberg (or Vaks-Larkin) model consisting of a system of interacting macro-spins aligned along a ring. Each spin has unit length and is described by its angle with respect to…

Earth and Planetary Astrophysics · Physics 2015-03-19 N. Mori , D. Schmitt , A. Ferriz-Mas , J. Wicht , H. Mouri , A. Nakamichi , M. Morikawa

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

We extend our recent derivation of the time evolution equations for the energy content of magnetic fields and turbulent motions for incompressible, homogeneous, and isotropic turbulence to include the case of nonvanishing helicity. These…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-14 Andrey Saveliev , Karsten Jedamzik , Guenter Sigl

In this study, we investigate preferences of dipolar magnetic structure from a seed magnetic field in the rapidly rotating spherical shell dynamo models. In this study, we set up a realistic model to show the effect of the Lorentz force in…

Geophysics · Physics 2018-06-15 Subhajit Kar

By numerically solving the equations of rotating magnetohydrodynamics (MHD), the magnetic effect on dynamical tide is studied. It is found that magnetic field has a significant impact not only on the flow structure, i.e. the internal shear…

Solar and Stellar Astrophysics · Physics 2018-02-21 Xing Wei

We analytically model the magnetization switching time of a biaxial ferromagnet driven by an antidamping-like spin torque. The macrospin magnetization dynamics is mapped to an energy-flow equation, wherein a rational-function approximation…

Applied Physics · Physics 2020-05-13 Ankit Shukla , Arun Parthasarathy , Shaloo Rakheja

We investigate the effect of a magnetic field on the global oscillation modes of a rotating fluid star in the magnetohydrodynamic approximation. We present general equations for the modification of any type of fluid mode due to a general…

Astrophysics · Physics 2009-11-07 Sharon M. Morsink , Vahid Rezania

A mechanism of current-induced magnetization reversal based on the parametric resonance is described. The source of the magnetization reversal is a current-induced magnetic field, which is applied perpendicularly to the easy axis of…

Mesoscale and Nanoscale Physics · Physics 2021-04-28 Vadym Zayets

A characteristic of spin reversal in the presence of phonon-bottleneck is the deviation of the magnetization cycle from a reversible function into an opened hysterezis cycle. In recent experiments on molecular magnets (e.g. V$_{15}$ and…

Mesoscale and Nanoscale Physics · Physics 2009-09-28 L. Chen , I. Chiorescu

The asymmetric time dependence and various statistical properties of polarity reversals of the Earth's magnetic field are utilized to infer some of the most essential parameters of the geodynamo, among them the effective (turbulent)…

Geophysics · Physics 2009-05-15 Michael Fischer , Gunter Gerbeth , Andre Giesecke , Frank Stefani

Two non-local asymptotic invariants of magnetic fields for the ideal magnetohydrodynamics are introduced. The velocity of variation of the invariants for a non-ideal magnetohydrodynamics with a small magnetic dissipation is estimated. By…

Mathematical Physics · Physics 2011-10-06 Petr M. Akhmet'ev

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