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We consider a framework for non-ideal magnetohydrodynamics in general relativity, paying particular attention to the physics involved. The discussion highlights the connection between the microphysics (associated with a given equation of…

High Energy Astrophysical Phenomena · Physics 2021-12-08 N. Andersson , I. Hawke , T. Celora , G. L. Comer

Binary systems of compact objects with electromagnetic field are modeled by helically symmetric Einstein-Maxwell spacetimes with charged and magnetized perfect fluids. Previously derived thermodynamic laws for helically-symmetric…

General Relativity and Quantum Cosmology · Physics 2010-12-23 Koji Uryu , Eric Gourgoulhon , Charalampos Markakis

We revise the structure-preserving finite element method in [K. Hu, Y. MA and J. Xu. (2017) Stable finite element methods preserving $\nabla \cdot \mathbf{B}=0$ exactly for MHD models. Numer. Math.,135, 371-396]. The revised method is…

Numerical Analysis · Mathematics 2020-03-24 Weifeng Qiu , Ke Shi

We develop a multiscale approach to describe the behavior of a suspension of solid magnetizable particles in a viscous non-conducting fluid in the presence of an externally applied magnetic field. By upscaling the quasi-static Maxwell…

Analysis of PDEs · Mathematics 2020-12-02 Grigor Nika , Bogdan Vernescu

Based on a rigorous thermodynamic framework, this work develops a two-fluid magnetohydrodynamic model grounded in the Helmholtz free energy formalism. The model maintains full thermodynamic consistency by simultaneously satisfying energy…

Plasma Physics · Physics 2025-11-07 Ting Xiao , Qiaolin He

In this paper we present a numerical method for hydrodynamic models that arise from time dependent density functional theories of freezing. The models take the form of compressible Navier-Stokes equations whose pressure is determined by the…

Numerical Analysis · Mathematics 2016-01-20 Arvind Baskaran , Zhen Guan , John Lowengrub

Magnetohydrostatic models of the solar atmosphere are often based on idealized analytic solutions because the underlying equations are too difficult to solve in full generality. Numerical approaches, too, are often limited in scope and have…

Solar and Stellar Astrophysics · Physics 2016-10-28 S. A. Gilchrist , D. C. Braun , G. Barnes

A mean-field Fokker-Planck equation approach to the dynamics of ferrofluids in the presence of a magnetic field and velocity gradients is proposed that incorporates magnetic dipole-dipole interactions of the colloidal particles. The model…

Soft Condensed Matter · Physics 2015-06-24 Patrick Ilg , Siegfried Hess

In gravitationally stratified fluids, length scales are normally much greater in the horizontal direction than in the vertical one. When modelling these fluids it can be advantageous to use the hydrostatic approximation, which filters out…

Instrumentation and Methods for Astrophysics · Physics 2013-07-29 Jonathan Braithwaite , Yuri Cavecchi

Ferrofluids are typically suspensions of magnetite nanoparticles, and behave as a homogeneous continuum. The production of nanoparticles with a narrow size distribution and the achievement of colloidal stability are important technological…

Fluid Dynamics · Physics 2017-04-04 S. Afkhami , Y. Renardy

The ideal magnetohydrodynamic equations are, roughly speaking, a quasi-linear symmetric hyperbolic system of PDEs, but not all the unknowns play the same role in this system. Indeed, in the regime of small magnetic fields, the equations are…

Analysis of PDEs · Mathematics 2021-03-01 Dimitri Cobb , Francesco Fanelli

The microscopic basis for the stability of itinerant ferromagnetism in correlated electron systems is examined. To this end several routes to ferromagnetism are explored, using both rigorous methods valid in arbitrary spatial dimensions, as…

Strongly Correlated Electrons · Physics 2009-10-30 D. Vollhardt , N. Blümer , K. Held , M. Kollar , J. Schlipf , M. Ulmke

The Landau-Lifshitz equation for the magnetization dynamics of a single-domain magnetic system is solved using the methods of self-organization. The description takes into account the torque due to spin transfer. The potential energy of the…

Materials Science · Physics 2007-05-23 P. M. Gorley , P. P. Horley , V. K. Dugaev , J. Barnas , W. Dobrowolski

We consider a ferrofluid cylinder, that is rotating with constant rotation frequency \Omega e_z as a rigid body. A homogeneous magnetic field H_0 e_x is applied perpendicular to the cylinder axis e_z. This causes a nonequilibrium situation.…

Fluid Dynamics · Physics 2007-05-23 A. Leschhorn , M. Lücke

In this work, we design an entropy stable, finite volume approximation for the ideal magnetohydrodynamics (MHD) equations. The method is novel as we design an affordable analytical expression of the numerical interface flux function that…

Numerical Analysis · Mathematics 2015-10-01 Andrew R. Winters , Gregor J. Gassner

This article reproduces the Karl Schwarzschild lecture 2013. Some of the basic ideas of electrodynamics and magnetohydrodynamics of mean fields in turbulently moving conducting fluids are explained. It is stressed that the connection of the…

Solar and Stellar Astrophysics · Physics 2014-02-27 K. -H. Rädler

The ideal MHD equations are a central model in astrophysics, and their solution relies upon stable numerical schemes. We present an implementation of a new method, which possesses excellent stability properties. Numerical tests demonstrate…

Instrumentation and Methods for Astrophysics · Physics 2011-04-28 Knut Waagan , Christoph Federrath , Christian Klingenberg

A continuum evolutionary model for micromagnetics is presented that, beside the standard magnetic balance laws, includes thermo-magnetic coupling. To allow conceptually efficient computer implementation, inspired by relaxation method of…

Analysis of PDEs · Mathematics 2013-02-06 Barbora Benešová , Martin Kružík , Tomáš Roubíček

We introduce an effective action for non-dissipative magnetohydrodynamics. A crucial guiding principle is the generalized global symmetry of electrodynamics, which naturally leads to introducing a "dual photon" as the degree of freedom…

High Energy Physics - Theory · Physics 2018-11-13 Paolo Glorioso , Dam Thanh Son

We report an observation of a stable soliton-like structure on the surface of a ferrofluid, generated by a local perturbation in the hysteretic regime of the Rosensweig instability. Unlike other pattern-forming systems with localized 2D…

Pattern Formation and Solitons · Physics 2009-11-11 Reinhard Richter , I. V. Barashenkov