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Related papers: An analytical dynamo solution for large-scale magn…

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We consider the magnetic helicity balance for the galactic dynamo in the framework of the local dynamo problem, as well as in the no-z model (which includes explicitly the radial distribution of the magnetic fields). When calculating the…

Astrophysics · Physics 2009-11-07 N. Kleeorin , D. Moss , I. Rogachevskii , D. Sokoloff

We present simulations of isolated disc galaxies in a realistic environment performed with the Tree-SPMHD-Code Gadget-3. Our simulations include a spherical circum-galactic medium (CGM) surrounding the galactic disc, motivated by…

Astrophysics of Galaxies · Physics 2018-11-28 Ulrich P. Steinwandel , Marcus C. Beck , Alexander Arth , Klaus Dolag , Benjamin P. Moster , Peter Nielaba

We present an efficient, robust computational method for modeling the Newtonian dynamics for rotation curve analysis of thin-disk galaxies. For a disk galaxy with a typical flat rotation curve, our modeling results show that the surface…

Astrophysics of Galaxies · Physics 2015-05-27 James Q. Feng , C. F. Gallo

In this paper, we develop a systematical approach in applying an asymptotic method of moving planes to investigate qualitative properties of positive solutions for fractional parabolic equations. We first obtain a series of needed key…

Analysis of PDEs · Mathematics 2020-06-26 Wenxiong Chen , Pengyan Wang , Yahui Niu , Yunyun Hu

The linear response of a thin superconducting strip subjected to an applied perpendicular time-dependent magnetic field is treated analytically using the method of matched asymptotic expansions. The calculation of the induced current…

Condensed Matter · Physics 2016-08-31 Alan T. Dorsey

We develop a new analytic solution for the steady-state structure of a thin accretion disc under the influence of a magnetic field that is anchored to the central star. The solution takes a form similar to that of Shakura and Sunyaev and…

Astrophysics · Physics 2009-11-10 O. M. Matthews , R. Speith , M. R. Truss , G. A. Wynn

We consider a two-dimensional MHD model describing the evolution of viscous, compressible and electrically conducting fluids under the action of vertical magnetic field without resistivity. Existence of global weak solutions is established…

Analysis of PDEs · Mathematics 2019-07-02 Yang Li , Yongzhong Sun

Using a one-dimensional $\alpha\omega$-dynamo model appropriate to galaxies, we study the possibility of dynamo action driven by a stochastic alpha effect and shear. To determine the field evolution, one needs to examine a large number of…

Astrophysics · Physics 2009-11-13 Sharanya Sur , Kandaswamy Subramanian

Using the classical approach we show the existence of disc type solutions to the asymptotic Plateau problem in certain Hadamard manifolds which may have arbitrarily strong curvature and volume growth.

Differential Geometry · Mathematics 2015-11-09 Jaime Ripoll , Friedrich Tomi

We study the asymptotic behavior of solutions to the Vlasov equation in the presence of a strong external magnetic field. In particular we provide a mathematically rigorous derivation of the guiding-center approximation in the general three…

Analysis of PDEs · Mathematics 2020-02-26 Francis Filbet , Luis Miguel Rodrigues

Two classes of stationary axisymmetric solutions of Einstein's equations for isolated differentially rotating matter sources are presented. The asymptotic regime is extracted, with attention to quasilocal gravitational energy, shear and…

General Relativity and Quantum Cosmology · Physics 2025-06-12 Marco Galoppo , David L. Wiltshire

With only a few exceptions, the numerical simulation of cosmic and laboratory hydromagnetic dynamos has been carried out in the framework of the differential equation method. However, the integral equation method is known to provide robust…

Astrophysics · Physics 2008-11-26 M. Xu , F. Stefani , G. Gerbeth

Astrophysical discs which are sufficiently massive and cool are linearly unstable to the formation of axisymmetric structures. In practice, linearly stable discs of surface density slightly below the threshold needed for this instability…

Earth and Planetary Astrophysics · Physics 2025-01-22 Joshua J. Brown , Gordon I. Ogilvie

The origin and evolution of cosmic magnetic fields as well as the influence of the magnetic fields on the evolution of galaxies are unknown. Though not without challenges, the dynamo theory can explain the large-scale coherent magnetic…

Astrophysics of Galaxies · Physics 2016-02-17 F. S. Tabatabaei , T. P. K. Martinsson , J. H. Knapen , J. E. Beckman , B. Koribalski , B. G. Elmegreen

We present the results of numerical integrations yielding the structure of and meridional flow in axisymmetric thin viscous accretion disk models. The solutions are obtained by simplifying and approximating first the equations, using…

Astrophysics · Physics 2009-11-07 O. Regev , L. Gitalman

This paper is concerned with the asymptotic behaviors of global strong solutions to the incompressible non-resistive viscous magnetohydrodynamic (MHD) equations with large initial perturbations in two-dimensional periodic domains in…

Analysis of PDEs · Mathematics 2021-02-16 Fei Jiang , Song Jiang

Using an effective Hamiltonian including the Zeeman and internal interactions, we describe the quantum theory of magnetization dynamics when the spin system evolves non-adiabatically and out of equilibrium. The Lewis-Riesenfeld dynamical…

Other Condensed Matter · Physics 2008-11-26 F. M. Saradzhev , F. C. Khanna , Sang Pyo Kim , M. de Montigny

Aims. Galaxy mass models based on simple and analytical functions for the density and potential pairs have been widely proposed in the literature. Disk models constrained by kinematic data alone give information on the global disk structure…

Astrophysics of Galaxies · Physics 2016-10-05 D. A. Barros , J. R. D. Lépine , W. S. Dias

In the context of astrophysical dynamos we illustrate that the no-cosines flow, with zero mean helicity, can drive fast dynamo action and study the dynamo's mode of operation during both the linear and non-linear saturation regime: It turns…

Astrophysics · Physics 2015-10-14 S. B. F. Dorch , V. D. Archontis

The set of all possible spherically symmetric magnetic static Einstein-Yang-Mills field equations for an arbitrary compact semi-simple gauge group $G$ was classified in two previous papers. Local analytic solutions near the center and a…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Todd A. Oliynyk , H. P. Kunzle