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Related papers: Non-local effects in the mean-field disc dynamo. I…

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The thin-disc global asymptotics are discussed for axisymmetric mean-field dynamos with vacuum boundary conditions allowing for non-local terms arising from a finite radial component of the mean magnetic field at the disc surface. This…

Astrophysics · Physics 2009-11-10 Ashley P. Willis , Anvar Shukurov , Andrew Soward , Dmitry Sokoloff

To explain the large-scale magnetic field of the Sun and other bodies, mean-field dynamo theory is commonly applied where one solves the averaged equations for the mean magnetic field. However, the standard approach breaks down when the…

Solar and Stellar Astrophysics · Physics 2018-06-06 A. Brandenburg , P. Chatterjee

We present an effectively global analytical asymptotic galactic dynamo solution for the regular magnetic field of an axisymmetric thin disc in the saturated state. This solution is constructed by combining two well-known types of local…

Astrophysics of Galaxies · Physics 2016-09-02 Luke Chamandy

The interstellar medium of the Milky Way and nearby disk galaxies harbours large-scale coherent magnetic fields of Microgauss strength, that can be explained via the action of a mean-field dynamo. As in our previous work, we aim to quantify…

Astrophysics of Galaxies · Physics 2020-03-18 Oliver Gressel , Detlef Elstner

We consider the effect of vertical outflows on the mean-field dynamo in a thin disk. These outflows could be due to winds or magnetic buoyancy. We analyse both two-dimensional finite-difference numerical solutions of the axisymmetric dynamo…

Astrophysics · Physics 2009-10-31 A. Bardou , B. v. Rekowski , W. Dobler , A. Brandenburg , A. Shukurov

We have extended our previous mean-field galactic dynamo model which included algebraic and dynamic alpha nonlinearities (Kleeorin et al., A&A, v. 387, 453, 2002), to include also a quenching of turbulent diffusivity. We readily obtain…

Astrophysics · Physics 2014-10-13 N. Kleeorin , D. Moss , I. Rogachevskii , D. Sokoloff

When scale separation in space and time is poor, the alpha effect and turbulent diffusivity have to be replaced by integral kernels. Earlier work in computing these kernels using the test-field method is now generalized to the case in which…

Solar and Stellar Astrophysics · Physics 2012-01-11 M. Rheinhardt , A. Brandenburg

The exploration of mean-field galactic dynamos affected by a galactic spiral pattern, begun in Chamandy et al. (2013, hereafter Paper I) with numerical simulations, is continued here with an asymptotic solution. The mean-field dynamo model…

Astrophysics of Galaxies · Physics 2015-06-12 Luke Chamandy , Kandaswamy Subramanian , Anvar Shukurov

We discuss asymptotic solutions of the kinematic $\alpha\omega$-dynamo in a thin disc (slab). Focusing upon the strong dynamo regime, in which the dynamo number $D$ satisfies $|D|\gg1$, we resolve uncertainties in the earlier treatments and…

Solar and Stellar Astrophysics · Physics 2014-07-16 Yameng Ji , Laura Cole , Paul Bushby , Anvar Shukurov

In evaluating neoclassical transport by radially-local simulations, the magnetic drift tangential to a flux surface is usually ignored in order to keep the phase-space volume conservation. In this paper, effect of the tangential magnetic…

Plasma Physics · Physics 2015-03-06 Seikichi Matsuoka , Shinsuke Satake , Ryutaro Kanno , Hideo Sugama

To obtain a simple description of a geometrically thin magnetic accretion disk, we apply the method of asymptotic expansion. For the first time we write a full set of stationary asymptotic approximation equations of a thin magnetic…

Solar and Stellar Astrophysics · Physics 2019-07-31 M. Čemeljić , W. Kluźniak , V. Parthasarathy

We study the dynamics of a twisted tilted disc under the influence of an external radiation field. Assuming the effect of absorption and reemission/scattering is that a pressure is applied to the disc surface where the local optical depth…

Astrophysics · Physics 2009-11-13 P. B. Ivanov , J. C. B. Papaloizou

Partial wave theory of a two dimensional scattering problem for an arbitray short range potential and a nonlocal Aharonov-Bohm magnetic flux is established. The scattering process of a ``hard disk'' like potential and the magnetic flux is…

Quantum Physics · Physics 2015-06-26 de-Hone Lin

We study local stability of the advection-dominated optically thick (slim) and optically thin discs with purely toroidal magnetic field and the radial viscous force using a linear perturbation analysis. Our dispersion relation indicates…

Astrophysics of Galaxies · Physics 2018-03-21 S. M. Ghoreyshi , Mohsen Shadmehri

We investigate the effect of the surface bipolar magnetic regions (BMR) on the large-scale dynamo distributed in the bulk of the convection zone. The study employs the nonlinear 3D mean-field dynamo model. We model the emergence of the BMR…

Solar and Stellar Astrophysics · Physics 2022-05-23 V. V. Pipin

We study the effects of vertical outflows on mean-field dynamos in disks. These outflows could be due to thermal winds or magnetic buoyancy. We analyse numerical solutions of the nonlinear mean-field dynamo equations using a two-dimensional…

Astrophysics · Physics 2007-05-23 B. von Rekowski , W. Dobler , A. Shukurov , A. Brandenburg

The theory of waves and instabilities in a differentially rotating disc containing a poloidal magnetic field is developed within the framework of ideal magnetohydrodynamics. A continuous spectrum, for which the eigenfunctions are localized…

Astrophysics · Physics 2009-10-30 G. I. Ogilvie

The first results of the solar dynamo model that allows for the diamagnetic effect of inhomogeneous turbulence and the nonlocal alpha-effect due to the rise of magnetic loops are discussed. The nonlocal alpha-effect is not subject to the…

Solar and Stellar Astrophysics · Physics 2015-05-27 L. L. Kitchatinov , S. V. Olemskoy

Dynamos in astrophysical disks are usually explained in terms of the standard alpha-omega mean field dynamo model where the local helicity generates a radial field component from an azimuthal field. The subsequent shearing of the radial…

Astrophysics · Physics 2015-06-24 Ethan T. Vishniac

Non-local effects in the optical response of noble metals are shown to produce significant blueshift and near-field quenching of plasmons in nanoparticle dimers, nanoshells, and thin metal waveguides. Compared with a local description…

Other Condensed Matter · Physics 2012-11-13 F. Javier Garcia de Abajo
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