English
Related papers

Related papers: Kinematic dynamos in triaxial ellipsoids

200 papers

Laminar electrically conducting Couette flows with the hydrodynamically stable quasi-Keplerian rotation profile and non-uniform conductivity are probed for dynamo instability. In spherical geometry the equations for the poloidal and the…

Fluid Dynamics · Physics 2022-06-29 G. Rüdiger , M. Schultz

Kinematic dynamo theory is presented here for turbulent conductive fluids. We describe how inhomogeneous magnetic fluctuations are generated below the viscous scale of turbulence where the spatial smoothness of the velocity permits a…

chao-dyn · Physics 2009-10-31 M. Chertkov , G. Falkovich , I. Kolokolov , M. Vergassola

We consider the free boundary problem for a plasma--vacuum interface in ideal incompressible magnetohydrodynamics. Unlike the classical statement, where the vacuum magnetic field obeys the div-curl system of pre-Maxwell dynamics, we do not…

Analysis of PDEs · Mathematics 2022-02-17 Paolo Secchi , Yuan Yuan

We investigate the nature of the dynamo bifurcation in a configuration applicable to the Earth's liquid outer core. Numerical studies on the stability domain of dipolar magnetic fields found a dichotomy between non-reversing…

Geophysics · Physics 2018-03-14 Ludovic Petitdemange

We consider the kinematic dynamo equations for a passive vector in $\mathcal{M} \times \mathbb{T} \subseteq \mathbb{R}^2 \times \mathbb{T}$ describing the evolution of a magnetic field with resistivity $\varepsilon>0$, that is transported…

Analysis of PDEs · Mathematics 2025-09-24 Víctor Navarro-Fernández , David Villringer

We present kinematic simulations of a galactic dynamo model based on the large scale differential rotation and the small scale helical fluctuations due to supernova explosions. We report for the first time direct numerical simulations of…

Astrophysics of Galaxies · Physics 2009-11-13 Christophe Gissinger , Sebastien Fromang , Emmanuel Dormy

The spatiotemporal structure formation problem is investigated in the region far above the transverse ferromagnetic resonance instability. The investigations are based on the dissipative Landau-Lifshitz equation and have been performed on a…

Pattern Formation and Solitons · Physics 2007-05-23 K. Mayes , T. Plefka , H. Sauermann

We study the kinematic dynamo equation on the three-torus and provide a rigorous proof of fast dynamo action for a time-periodic, divergence-free, Lipschitz velocity field. Our construction is based on a stretch-fold-shear mechanism…

Analysis of PDEs · Mathematics 2026-05-20 Michele Coti Zelati , Massimo Sorella , David Villringer

The turbulent dynamo may explain the origin of cosmic magnetism. While the exponential amplification of magnetic fields has been studied for incompressible gases, little is known about dynamo action in highly-compressible, supersonic…

Astrophysics of Galaxies · Physics 2014-12-05 Christoph Federrath , Jennifer Schober , Stefano Bovino , Dominik R. G. Schleicher

We present a unified three-dimensional model of the convection zone and upper atmosphere of the Sun in spherical geometry. In this model, magnetic fields, generated by a helically forced dynamo in the convection zone, emerge without the…

Solar and Stellar Astrophysics · Physics 2011-06-14 Jörn Warnecke , Axel Brandenburg , Dhrubaditya Mitra

We present a novel method to investigate the dynamics of a single semiflexible polymer, subject to anisotropic friction in a viscous fluid. In contrast to previous approaches, we do not rely on a discrete bead-rod model, but introduce a…

Biomolecules · Quantitative Biology 2009-11-13 Tobias Munk , Oskar Hallatschek , Chris H. Wiggins , Erwin Frey

An initial boundary value problem for compressible Magnetohydrodynamics (MHD) is considered on an exterior domain (with the first Betti number vanishes) in $R^3$ in this paper. The global existence of smooth solutions near a given constant…

Analysis of PDEs · Mathematics 2022-11-23 Hairong Liu , Tao Luo , Hua Zhong

Spectropolarimetric observations show that many low-mass stars possess large-scale poloidal magnetic fields with considerable dipole component, which in some cases exhibit temporal dynamics - cycles or reversals. Although it is widely…

Solar and Stellar Astrophysics · Physics 2025-07-02 Anna Guseva , Ludovic Petitdemange , Charly Pinçon

(abidged) Context: Stellar convection zones are characterized by vigorous high-Reynolds number turbulence at low Prandtl numbers. Aims: We study the dynamo and differential rotation regimes at varying levels of viscous, thermal, and…

Solar and Stellar Astrophysics · Physics 2017-02-22 P. J. Käpylä , M. J. Käpylä , N. Olspert , J. Warnecke , A. Brandenburg

Recent advances in cold-atom platforms have made real-time dynamics accessible, renewing interest in the motion of superfluid vortices in two-dimensional domains. Here we show that the energy and the trajectories of arbitrary vortex…

Quantum Gases · Physics 2024-08-12 Matteo Caldara , Andrea Richaud , Pietro Massignan , Alexander L. Fetter

We consider a free boundary problem for the axially symmetric incompressible ideal magnetohydrodynamic equations that describes the motion of the plasma in vacuum. Both the plasma magnetic field and vacuum magnetic field are tangent along…

Analysis of PDEs · Mathematics 2017-11-28 Xumin Gu

By modelling the upper layers of the Sun in terms of a two-layer setup where a free-surface exists within the computational domain, we numerically study the interaction between the surface gravity, or the fundamental ($f$) mode, and the…

Solar and Stellar Astrophysics · Physics 2026-02-06 Rajesh Mondal , Nishant K. Singh

We present a novel numerical method that allows the calculation of nonlinear force-free magnetostatic solutions above a boundary surface on which only the distribution of the normal magnetic field component is given. The method relies on…

Solar and Stellar Astrophysics · Physics 2015-05-20 Ioannis Contopoulos , Constantinos Kalapotharakos , Manolis Georgoulis

We consider the full 3D dynamics of a thin falling liquid film on a flat plate inclined at some non-zero angle to the horizontal. In addition to gravitational effects, the flow is driven by an electric field, which is normal to the…

Fluid Dynamics · Physics 2017-08-02 R. J. Tomlin , D. T. Papageorgiou , G. A. Pavliotis

Several one and two dimensional mean field models are analyzed where the effects of current helicity fluxes and boundaries are included within the framework of the dynamical quenching model. In contrast to the case with periodic boundary…

Astrophysics · Physics 2007-05-23 Axel Brandenburg , Kandaswamy Subramanian