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Related papers: Suppression of a kinematic dynamo by large shear

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Shear flows are naturally expected to occur in astrophysical environments and potential sites of continuous non-thermal Fermi-type particle acceleration. Here we investigate the efficiency of expanding relativistic outflows to facilitate…

High Energy Astrophysical Phenomena · Physics 2016-12-14 F. M. Rieger , P. Duffy

The dynamics of two-dimensional viscous vesicles in shear flow, with different fluid viscosities $\eta_{\rm in}$ and $\eta_{\rm out}$ inside and outside, respectively, is studied using mesoscale simulation techniques. Besides the well-known…

Soft Condensed Matter · Physics 2016-08-17 Sebastian Meßlinger , Benjamin Schmidt , Hiroshi Noguchi , Gerhard Gompper

Most large-scale planetary magnetic fields are thought to be driven by low Rossby number convection of a low magnetic Prandtl number fluid. Here kinematic dynamo action is investigated with an asymptotic, rapidly rotating dynamo model for…

Geophysics · Physics 2016-12-14 Michael A. Calkins , Louie Long , David Nieves , Keith Julien , Steven M. Tobias

Kinematic simulations of the induction equation are carried out for different setups suitable for the von-K\'arm\'an-Sodium (VKS) dynamo experiment. Material properties of the flow driving impellers are considered by means of high…

Fluid Dynamics · Physics 2015-03-13 A. Giesecke , C. Nore , F. Luddens , F. Stefani , G. Gerbeth , J. Léorat , J. -L. Guermond

We numerically study the effects of varying electric conductivity and magnetic permeability of the bounding wall on a kinematic dynamo in a sphere for parameters relevant to Madison plasma dynamo experiment (MPDX). The dynamo is excited by…

We report the results of simulations of rigid colloidal helices suspended in a shear flow, using dissipative particle dynamics for a coarse-grained representation of the suspending fluid, as well as deterministic trajectories of…

Soft Condensed Matter · Physics 2020-08-13 Brian W. Rost , Justin T. Stimatze , David A. Egolf , Jeffrey S. Urbach

To understand the generation of the Earth's and planetary magnetic fields, we investigate numerically the combined effect of precession and convection on the dynamo action in a spherical shell. The convection alone, the precession alone and…

Earth and Planetary Astrophysics · Physics 2016-08-24 Xing Wei

We consider the evolution of arbitrarily large perturbations of a prescribed pure hydrodynamical flow of an electrically conducting fluid. We study whether the flow perturbations as well as the generated magnetic fields decay or grow with…

Fluid Dynamics · Physics 2021-05-04 Itzhak Fouxon , Joshua Feinberg , Michael Mond

Context: Large-scale magnetic fields resulting from hydromagnetic dynamo action may differ substantially in their time dependence. Cyclic field variations, characteristic for the solar magnetic field, are often explained by an important…

Solar and Stellar Astrophysics · Physics 2015-05-27 M. Schrinner , L. Petitdemange , E. Dormy

We reveal and investigate a new type of linear axisymmetric helical magnetorotational instability which is capable of destabilizing viscous and resistive rotational flows with radially increasing angular velocity, or positive shear. This…

Fluid Dynamics · Physics 2019-10-23 G. Mamatsashvili , F. Stefani , R. Hollerbach , G. Rüdiger

Some recent results and open issues in magnetic dynamo theory are addressed. The distinction between small-scale and mean-field dynamo (MFD) action in forced turbulent flows is emphasized. Though useful, the MFD has been controversial. This…

Astrophysics · Physics 2007-05-23 Eric G. Blackman

It has been hypothesized that the sustained narrowness observed in the asymptotic cylindrical region of bipolar outflows from Young Stellar Objects (YSO) indicates that these jets are magnetically collimated. The j cross B force observed in…

Astrophysics · Physics 2009-06-23 Lucas Wanex , Erik Tendeland

The effect of a spatially uniform magnetic field on the shear rheology of a dilute emulsion of monodispersed ferrofluid droplets, immersed in a non-magnetizable immiscible fluid, is investigated using direct numerical simulations. The…

Soft Condensed Matter · Physics 2021-08-04 Paolo Capobianchi , Marcello Lappa , Mónica S. N. Oliveira , Fernando T. Pinho

This paper demonstrates an equivalence between rotating magnetised shear flows and a stressed elastic beam. This results from finding the same form of dynamical equations after an asymptotic reduction of the axis-symmetric magnetorotational…

Solar and Stellar Astrophysics · Physics 2018-04-30 Geoff Vasil

We numerically compute the flow of an electrically conducting fluid in a Taylor-Couette geometry where the rotation rates of the inner and outer cylinders satisfy $\Omega_o/\Omega_i=(r_o/r_i)^{-3/2}$. In this quasi-Keplerian regime a…

Fluid Dynamics · Physics 2017-10-25 Anna Guseva , Rainer Hollerbach , Ashley P. Willis , Marc Avila

Dynamo action in planetary cores has been extensively studied in the context of convectively-driven flows. We show in this letter that mechanical forcings, namely tides, libration and precession, are also able to kinematically sustain a…

Fluid Dynamics · Physics 2018-11-07 K. Sandeep Reddy , Benjamin Favier , Michael Le Bars

A convection-driven MHD dynamo in a rotating spherical shell, with clearly defined structural elements in the flow and magnetic field, is simulated numerically. Such dynamos can be called deterministic, in contrast to those explicitly…

Astrophysics · Physics 2008-11-26 A. V. Getling , R. D. Simitev , F. H. Busse

The relative importance of the helicity and cross-helicity electromotive dynamo effects for self-sustained magnetic field generation by chaotic thermal convection in rotating spherical shells is investigated as a function of shell…

Fluid Dynamics · Physics 2020-12-18 Luis Silva , Parag Gupta , David MacTaggart , Radostin D. Simitev

The shape dynamics of fluid vesicles is governed by the coupling of the flow within the two-dimensional membrane to the hydrodynamics of the surrounding bulk fluid. We present a numerical scheme which is capable of solving this flow problem…

Condensed Matter · Physics 2009-10-28 Martin Kraus , Wolfgang Wintz , Udo Seifert , Reinhard Lipowsky

At large magnetic Reynolds numbers, magnetic helicity evolution plays an important role in astrophysical large-scale dynamos. The recognition of this fact led to the development of the dynamical alpha quenching formalism, which predicts…

Solar and Stellar Astrophysics · Physics 2012-03-08 Alexander Hubbard , Axel Brandenburg
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