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相关论文: An example of anti-dynamo conformal Arnold metric

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Two examples of magnetic anti-dynamos in magnetohydrodynamics (MHD) are given. The first is a 3D metric conformally related to Arnold cat fast dynamo metric: ${ds_{A}}^{2}=e^{-{\lambda}z}dp^{2}+e^{{\lambda}z}dq^{2}+dz^{2}$ is shown to…

天体物理学 · 物理学 2007-05-23 L. . Garcia de Andrade

Earlier Arnold, Zeldovich, Ruzmaikin and Sokoloff [\textbf{JETP (1982)}] have computed the eigenvalue of a uniform stretching torus transformation which result on the first Riemann metric solution of the dynamo action problem. Recently some…

数学物理 · 物理学 2008-11-04 Garcia de Andrade

It is shown that C-flows in Riemannian three-dimensional compact manifold can be naturally considered as generalized dynamo Arnold's metric in compact manifolds, the so-called cat map dynamo. The generalized solution of self-induction…

数学物理 · 物理学 2008-03-06 L Garcia de Andrade

Chicone et al [Comm Math Phys (1997)] investigated existence of fast dynamos by analyzing the spectrum kinematic magnetic dynamo. In real non-degenerate branch of the spectrum, the kinematic dynamo operator lies on a compact Riemannian 2D…

宇宙学与河外天体物理 · 物理学 2010-02-10 Garcia de Andrade

We establish a one-to-one correspondence between K\"ahler metrics in a given conformal class and parallel sections of a certain vector bundle with conformally invariant connection, where the parallel sections satisfy a set of non--linear…

微分几何 · 数学 2025-07-30 Maciej Dunajski , A. Rod Gover

Curvature and helicity topological bounds for the magnetic energy of the streamlines magnetic structures of a kinematic dynamo flow are computed. The existence of the filament dynamos are determined by solving the magnetohydrodynamic…

天体物理学 · 物理学 2007-05-23 L. C. Garcia de Andrade

Assuming the stability of soliton surfaces of vanishing Ricci sectional curvature of soliton metric in the nonholonomic frame, we find a solution for the metric in the approximation of weak constant torsion curves with constant Frenet…

流体动力学 · 物理学 2007-08-15 Garcia de Andrade

In this work, we study nonconformally Ricci-flat gravitational instantons in four-dimensional Conformal Gravity, both in vacuum and in the presence of nonlinear conformal matter. First, the one-parameter extension of the Kerr-NUT-AdS metric…

高能物理 - 理论 · 物理学 2026-03-09 Cristóbal Corral , Borja Diez , Eleftherios Papantonopoulos

Chicone et al [CMP (1995)] have shown that, kinematic fast dynamos in diffusive media, could exist only on a closed, 2D Riemannian manifold of constant negative curvature. This report, shows that their result cannot be extended to…

等离子体物理 · 物理学 2009-06-17 Garcia de Andrade

Let $M$ be a compact 2-dimensional Riemannian manifold with smooth boundary and consider the incompressible Euler equation on $M$. In the case that $M$ is the straight periodic channel, the annulus or the disc with the Euclidean metric, it…

微分几何 · 数学 2022-03-22 Taito Tauchi , Tsuyoshi Yoneda

Magnetic curvature effects, investigated by Barrow and Tsagas (BT) [Phys Rev D \textbf{77},(2008)],as a mechanism for magnetic field decay in open Friedmann universes (${\Lambda}<0$), are applied to dynamo geometric Ricci flows in 3D curved…

广义相对论与量子宇宙学 · 物理学 2009-05-14 Garcia de Andrade

We consider the problem of extending a conformal metric of negative curvature, given outside a neighbourhood of 0 in the unit disk $\DD$, to a conformal metric of negative curvature in $\DD$. We give conditions under which such an extension…

微分几何 · 数学 2007-05-23 Dan Mangoubi

We show for unit dynamical exponent, $z=1$, the appearance of the Fermi liquid and non-Fermi liquid behavior as we tune the charge density and the magnetic field in 3+1 dimensional field theory using the gauge-gravity duality. There exists…

高能物理 - 理论 · 物理学 2012-02-17 Shesansu Sekhar Pal

We consider four-dimensional, Riemannian, Ricci-flat metrics for which one or other of the self-dual or anti-self-dual Weyl tensors is type-D. Such metrics always have a valence-2 Killing spinor, and therefore a Hermitian structure and at…

广义相对论与量子宇宙学 · 物理学 2021-10-28 Paul Tod

Within a framework of noncommutative geometry, we develop an analogue of (pseudo) Riemannian geometry on finite and discrete sets. On a finite set, there is a counterpart of the continuum metric tensor with a simple geometric…

广义相对论与量子宇宙学 · 物理学 2009-10-31 A. Dimakis , F. Muller-Hoissen

A conformal metric $g$ with constant curvature one and finite conical singularities on a compact Riemann surface $\Sigma$ can be thought of as the pullback of the standard metric on the 2-sphere by a multi-valued locally univalent…

微分几何 · 数学 2016-01-20 Qing Chen , Wei Wang , Yingyi Wu , Bin Xu

Examples of conformal dynamo maps have been presented earlier [Phys Plasmas \textbf{14}(2007)] where fast dynamos in twisted magnetic flux tubes in Riemannian manifolds were obtained. This paper shows that conformal maps, under the Floquet…

数学物理 · 物理学 2008-10-23 Garcia de Andrade

The "dancing metric" is a pseudo-riemannian metric $\pmb{g}$ of signature $(2,2)$ on the space $M^4$ of non-incident point-line pairs in the real projective plane $\mathbb{RP}^2$. The null-curves of $(M^4,\pmb{g})$ are given by the "dancing…

微分几何 · 数学 2015-10-06 Gil Bor , Luis Hernández Lamoneda , Pawel Nurowski

In order to minimize a differentiable geodesically convex function, we study a second-order dynamical system on Riemannian manifolds with an asymptotically vanishing damping term of the form $\alpha/t$. For positive values of $\alpha$,…

最优化与控制 · 数学 2023-12-12 Tejas Natu , Camille Castera , Jalal Fadili , Peter Ochs

In this paper we define an orientation of a measured Gromov-Hausdorff limit space of Riemannian manifolds with uniform Ricci bounds from below. This is the first observation of orientability for metric measure spaces. Our orientability has…

微分几何 · 数学 2017-10-30 Shouhei Honda
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