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Related papers: Dynamo experiments in torsioned toroidal devices

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Accretion disc turbulence is investigated in the framework of the shearing box approximation. The turbulence is either driven by the magneto-rotational instability or, in the non-magnetic case, by an explicit and artificial forcing term in…

Astrophysics · Physics 2008-11-26 Axel Brandenburg

A mean-field theory of the electrodynamics of a turbulent fluid is formulated under the assumption that the molecular electric conductivity is correlated with the turbulent velocity fluctuation in the (radial) direction, $\mathbf{g}$. It is…

Fluid Dynamics · Physics 2023-05-03 Oliver Gressel , Günther Rüdiger , Detlef Elstner

We report an experimental investigation on the influence of an external magnetic field on forced 3D turbulence of liquid gallium in a closed vessel. We observe an exponential damping of the turbulent velocity fluctuations as a function of…

Fluid Dynamics · Physics 2015-05-14 Basile Gallet , Michael Berhanu , Nicolas Mordant

The Tayler-Spruit dynamo mechanism has been proposed two decades ago as a plausible mechanism to transport angular momentum in radiative stellar layers. Direct numerical simulations are still needed to understand its trigger conditions and…

Solar and Stellar Astrophysics · Physics 2024-01-18 Ludovic Petitdemange , Florence Marcotte , Christophe Gissinger , Florentin Daniel

Supernovae are the dominant energy source for driving turbulence within the interstellar plasma. Until recently, their effects on magnetic field amplification in disk galaxies remained a matter of speculation. By means of self-consistent…

Astrophysics · Physics 2009-11-13 Oliver Gressel , Udo Ziegler , Detlef Elstner , Günther Rüdiger

We study dynamo action in a convective layer of electrically-conducting, compressible fluid, rotating about the vertical axis. At the upper and lower bounding surfaces, perfectly-conducting boundary conditions are adopted for the magnetic…

Solar and Stellar Astrophysics · Physics 2011-11-23 Benjamin F. N. Favier , Paul J. Bushby

The project DRESDYN (DREsden Sodium facility for DYNamo and thermohydraulic studies) conducted at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) provides a new platform for a variety of liquid sodium experiments devoted to problems of geo- and…

Fluid Dynamics · Physics 2019-05-22 Andre Giesecke , Tobias Vogt , Thomas Gundrum , Frank Stefani

In the last decades, the experimental study of dynamo action has made great progress. However, after the dynamo experiments in Karlsruhe and Riga, the von-Karman-Sodium (VKS) dynamo is only the third facility that has been able to…

When a star gets tidally disrupted by a supermassive black hole, its magnetic field is expected to pervade its debris. In this paper, we study this process via smoothed particle magnetohydrodynamical simulations of the disruption and early…

High Energy Astrophysical Phenomena · Physics 2017-06-28 Clément Bonnerot , Daniel J. Price , Giuseppe Lodato , Elena M. Rossi

Magnetized plasma columns and extended magnetic structures with both footpoints anchored to a surface layer are an important building block of astrophysical dissipation models. Current loops shining in X-rays during the growth of plasma…

Solar and Stellar Astrophysics · Physics 2024-05-07 Natalie Rugg , Jens F. Mahlmann , Anatoly Spitkovsky

We present the new results of the two-dimensional numerical experiments on the cross-sectional evolution of a twisted magnetic flux tube rising from the deeper solar convection zone (-20,000 km) to the corona through the surface. The…

Solar and Stellar Astrophysics · Physics 2015-05-28 Shin Toriumi , Takaaki Yokoyama

In this paper we discuss a dynamic flux-transport dynamo model that includes the feedback of the induced magnetic field on differential rotation and meridional flow. We consider two different approaches for the feedback: meanfield Lorentz…

Astrophysics · Physics 2009-11-11 Matthias Rempel

Context: Convectively-driven flows play a crucial role in the dynamo processes that are responsible for producing magnetic activity in stars and planets. It is still not fully understood why many astrophysical magnetic fields have a…

Solar and Stellar Astrophysics · Physics 2018-05-09 P. J. Bushby , P. J. Käpylä , Y. Masada , A. Brandenburg , B. Favier , C. Guervilly , M. J. Käpylä

Stellar magnetism plays an important role in stellar evolution theory. Approximatively 10% of observed main sequence (MS) and pre-main-sequence (PMS) radiative stars exhibit surface magnetic fields above the detection limit, raising the…

Solar and Stellar Astrophysics · Physics 2018-01-24 Jérémie Vidal , David Cébron , Nathanaël Schaeffer , Rainer Hollerbach

We numerically demonstrate the feasibility of kinematic fast dynamos for a class of time-periodic axisymmetric flows of conducting fluid confined inside a sphere. The novelty of our work is in considering the realistic flows, which are…

Plasma Physics · Physics 2013-09-19 I. V. Khalzov , C. M. Cooper , C. B. Forest

Astrophysical fluids are generically turbulent and this must be taken into account for most transport processes. We discuss how the preexisting turbulence modifies magnetic reconnection and how magnetic reconnection affects the MHD…

Astrophysics of Galaxies · Physics 2015-06-03 A. Lazarian , G. Eyink , E. Vishniac

We examine the relationship between magnetic flux generation, taken as an indicator of large-scale dynamo action, and magnetic helicity, computed as an integral over the dynamo volume, in a simple dynamo. We consider dynamo action driven by…

High Energy Astrophysical Phenomena · Physics 2017-07-19 G. Bodo , F. Cattaneo , A. Mignone , P. Rossi

We study the onset of spin superfluidity, namely coherent spin transport mediated by a topological spin texture, in frustrated exchange-dominated magnetic systems, engendered by an external magnetic field. We show that for typical device…

Mesoscale and Nanoscale Physics · Physics 2021-05-26 Ricardo Zarzuela , Daniel Hill , Jairo Sinova , Yaroslav Tserkovnyak

The nonlinear dynamo effect of tearing modes is derived with the resistive MHD equations. The dynamo effect is divided into two parts, parallel and perpendicular to the magnetic field. Firstly, the force-free plasma is considered. It is…

Plasma Physics · Physics 2021-01-12 Luo Yuhang , Gao Zhe

The induced current density, corresponding to the massless Dirac equation in (2+1) dimensions in a magnetic flux tube of small radius is considered. This problem is important for graphene. In the case, when an electron can not penetrate the…

Mesoscale and Nanoscale Physics · Physics 2013-05-29 Alexander I. Milstein , Ivan S. Terekhov