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Related papers: Small-scale dynamo with nonzero correlation time

200 papers

We consider magnetic fields generated by homogeneous isotropic and parity invariant turbulent flows. We show that simple scaling laws for dynamo threshold, magnetic energy and Ohmic dissipation can be obtained depending on the value of the…

Fluid Dynamics · Physics 2009-11-13 Stephan Fauve , Francois Petrelis

We re-analyze the Olesen arguments on the self-similarity properties of freely evolving, nonhelical magnetohydrodynamic turbulence. We find that a necessary and sufficient condition for the kinetic and magnetic energy spectra to evolve…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-20 Leonardo Campanelli

We consider the kinematic dynamo equations for a passive vector in $\mathcal{M} \times \mathbb{T} \subseteq \mathbb{R}^2 \times \mathbb{T}$ describing the evolution of a magnetic field with resistivity $\varepsilon>0$, that is transported…

Analysis of PDEs · Mathematics 2025-09-24 Víctor Navarro-Fernández , David Villringer

We revisit the various approximations employed to study the long-term evolution of the magnetic field in neutron star cores and discuss their limitations and possible improvements. A recent controversy on the correct form of the induction…

High Energy Astrophysical Phenomena · Physics 2017-06-28 Andrea Passamonti , Taner Akgün , José Pons , Juan Antonio Miralles

It has been recently shown numerically that a small-scale dynamo (SSD) instability could be possible in solar-like low magnetic Prandtl number plasmas. It has been proposed that the presence of SSD can potentially have a significant impact…

Solar and Stellar Astrophysics · Physics 2025-04-09 Jörn Warnecke , Maarit J. Korpi-Lagg , Matthias Rheinhard , Mariangela Viviani , Ameya Prabhu

We study the long term evolution of magnetic fields generated by an initially unmagnetized collisionless relativistic $e^+e^-$ shock. Our 2D particle-in-cell numerical simulations show that downstream of such a Weibel-mediated shock,…

Astrophysics · Physics 2009-06-23 Philip Chang , Anatoly Spitkovsky , Jonathan Arons

We investigate the structure of magnetic field amplified by turbulent velocity fluctuations, in the framework of the kinematic Kazantsev-Kraichnan model. We consider Kolmogorov distribution of velocity fluctuations, and assume that both…

Astrophysics · Physics 2010-01-15 Leonid Malyshkin , Stanislav Boldyrev

We study a new type of large-scale instability, which arises in obliquely rotating stratified electroconductive fluid with an external uniform magnetic field and a small-scale external force having zero helicity. This force gives rise to…

Fluid Dynamics · Physics 2018-07-06 M. I. Kopp , K. N. Kulik , A. V. Tur , V. V. Yanovsky

The $\Lambda$ effect describes a rotation-induced non-diffusive contribution to the Reynolds stress. It is commonly held responsible for maintaining the observed differential rotation of the Sun and other late-type stars. Here the…

Solar and Stellar Astrophysics · Physics 2020-02-18 Petri J. Käpylä

This work concentrates on the effect of an irrotational forcing on a magnetized flow in the presence of rotation, baroclinicity, shear, or a combination of them. By including magnetic field in the model we can evaluate the occurrence of…

Astrophysics of Galaxies · Physics 2023-09-08 Albert Elias-López , Fabio Del Sordo , Daniele Viganò

We study magnetic field evolution in flows with fluctuating in time governing parameters in electrically conducting fluid. We use a standard mean-field approach to derive equations for large-scale magnetic field for the fluctuating ABC-flow…

Astrophysics · Physics 2009-11-13 N. Kleeorin , I. Rogachevskii , D. Sokoloff , D. Tomin

Numerical MHD simulations play increasingly important role for understanding mechanisms of stellar magnetism. We present simulations of convection and dynamos in density-stratified rotating spherical fluid shells. We employ a new 3D…

Solar and Stellar Astrophysics · Physics 2015-09-03 Radostin D. Simitev , Alexander G. Kosovichev , Friedrich H. Busse

At lowest order comoving magnetic fields which are frozen-into the expanding cosmic fluid do not evolve in time. At next-to-leading order the induction equation is sourced by the interaction term between the baryon velocity and the magnetic…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-21 Kerstin E. Kunze

We measure the decay rates of magnetic field modes in a turbulent flow of liquid sodium below the dynamo threshold.We observe that turbulent fluctuations induce energy transfers between modes with different symmetries (dipolar and…

Fluid Dynamics · Physics 2014-11-04 Johann Herault , François Pétrélis , Stephan Fauve

The real-time dynamics of local magnetic moments exchange coupled to a metallic system of conduction electrons is subject to dissipative friction even in the absence of spin-orbit coupling. Phenomenologically, this is usually described by a…

Mesoscale and Nanoscale Physics · Physics 2025-01-08 Nicolas Lenzing , David Krüger , Michael Potthoff

We investigated the influence of small scale magnetic energy ($E_M$) and magnetic helicity ($H_M$) on the growth rate ($\gamma$) of large scale magnetic field ($\overline{{\bf B}}$). $H_M$ that plays a key role in MHD dynamo is a…

Plasma Physics · Physics 2014-09-22 Kiwan Park

While the saturated magnetic energy is independent of viscosity in dynamo experiments, it remains viscosity-dependent in state-of-the-art 3D direct numerical simulations (DNS). Extrapolating such viscous scaling-laws to realistic parameter…

Fluid Dynamics · Physics 2017-12-20 Kannabiran Seshasayanan , Basile Gallet , Alexandros Alexakis

We investigate the effect of large magnetic fields on the $2+1$ dimensional reduced-magnetohydrodynamical expansion of hot and dense nuclear matter produced in $\sqrt{s_{\rm NN}}$ = 200 GeV Au+Au collisions. For the sake of simplicity, we…

Nuclear Theory · Physics 2017-12-19 Victor Roy , Shi Pu , Luciano Rezzolla , Dirk H. Rischke

We present a new description of cosmological evolution of the primordial magnetic field under the condition that it is non-helical and its energy density is larger than the kinetic energy density. We argue that the evolution can be…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-28 Fumio Uchida , Motoko Fujiwara , Kohei Kamada , Jun'ichi Yokoyama

We study the nonlinear evolution of the magnetic Rayleigh-Taylor instability using three-dimensional MHD simulations. We consider the idealized case of two inviscid, perfectly conducting fluids of constant density separated by a contact…

Astrophysics · Physics 2009-11-13 James M. Stone , Thomas A. Gardiner