English
Related papers

Related papers: Cross-helicity effect on $\alpha$-type dynamo in n…

200 papers

The existence of partially conserved enstrophy-like quantities is conjectured to cause inverse energy transfers to develop embedded in magnetohydrodynamical (MHD) turbulence, in analogy to the influence of enstrophy in two-dimensional…

Fluid Dynamics · Physics 2020-01-08 Nicholas Rathmann , Peter Ditlevsen

We use direct and stochastic numerical simulations of the magnetohydrodynamic equations to explore the influence of turbulence on the dynamo threshold. In the spirit of the Kraichnan-Kazantsev model, we model the turbulence by a noise, with…

We present results of Reynolds-averaged turbulence model simulation on the problem of magnetic reconnection. In the model, in addition to the mean density, momentum, magnetic field, and energy equations, the evolution equations of the…

Plasma Physics · Physics 2020-01-08 Fabien Widmer , Jörg Büchner , Nobumitsu Yokoi

Several one and two dimensional mean field models are analyzed where the effects of current helicity fluxes and boundaries are included within the framework of the dynamical quenching model. In contrast to the case with periodic boundary…

Astrophysics · Physics 2007-05-23 Axel Brandenburg , Kandaswamy Subramanian

Planetary and stellar dynamos likely result from turbulent motions in magnetofluids with kinematic viscosities that are small compared to their magnetic diffusivities. Laboratory experiments are in progress to produce similar dynamos in…

Astrophysics · Physics 2009-11-11 P. D. Mininni

Recent progress regarding the noncanonical Hamiltonian formulation of extended magnetohydrodynamics (XMHD), a model with Hall drift and electron inertia, is summarized. The advantages of the Hamiltonian approach are invoked to study some…

Plasma Physics · Physics 2017-01-05 George Miloshevich , Manasvi Lingam , Philip J. Morrison

The dynamics of spectral transport in two-dimensional turbulent convection of electrically conducting fluids is studied by means of direct numerical simulations (DNS) in the frame of the magnetohydrodynamic (MHD) Boussinesq approximation.…

Solar and Stellar Astrophysics · Physics 2015-05-13 Dan Škandera , Wolf-Christian Müller

Turbulence is the most common state of astrophysical flows. In typical astrophysical fluids, turbulence is accompanied by strong magnetic fields, which has a large impact on the dynamics of the turbulent cascade. Recently, there has been a…

Astrophysics · Physics 2011-05-10 Jungyeon Cho , A. Lazarian , Ethan Vishniac

We use numerical simulations to study the effect of nonlinear MHD waves in a stratified, self-gravitating molecular cloud that is bounded by a hot and tenuous external medium. In a previous paper, we had shown the details of a standard…

Astrophysics · Physics 2009-11-11 Takahiro Kudoh , Shantanu Basu

The nonlinear transfer rate of the total energy (transfer rate of kinetic energy + transfer rate due to the work done by the magnetization) for an incompressible turbulent ferrofluid system is studied under the assumption of statistical…

Fluid Dynamics · Physics 2024-05-08 Sukhdev Mouraya , Nandita Pan , Supratik Banerjee

We conduct 3D magnetohydrodynamic (MHD) simulations of decaying turbulence in the solar wind context. To account for the spherical expansion of the solar wind, we implement the expanding box model. The initial turbulence comprises…

Solar and Stellar Astrophysics · Physics 2025-01-27 Chen Shi , Nikos Sioulas , Zesen Huang , Marco Velli , Anna Tenerani , Victor Réville

Recent numerical simulations showed that the mean flow is generated in inhomogeneous turbulence of an incompressible fluid accompanied with helicity and system rotation. In order to investigate the mechanism of this phenomenon, we carry out…

Fluid Dynamics · Physics 2024-09-16 K. Inagaki , N. Yokoi , F. Hamba

The standard magnetohydrodynamic (MHD) description of the plasma in the hot, magnetized gas of the intra-cluster (ICM) medium is not adequate because it is weakly collisional. In such collisionless magnetized gas, the microscopic velocity…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 R. Santos-Lima , E. M. de Gouveia Dal Pino , A. Lazarian , G. Kowal , D. Falceta-Gonçalves

In numerical studies of turbulence, hyperviscosity is often used as a tool to extend the inertial subrange and to reduce the dissipative subrange. By analogy, hyperdiffusivity (or hyperresistivity) is sometimes used in magnetohydrodynamics.…

Astrophysics · Physics 2009-11-07 Axel Brandenburg , Graeme R. Sarson

We examine the effects of density stratification on magnetohydrodynamic turbulence driven by the magnetorotational instability in local simulations that adopt the shearing box approximation. Our primary result is that, even in the absence…

High Energy Astrophysical Phenomena · Physics 2014-11-20 S. W. Davis , J. M. Stone , M. E. Pessah

In mean-field magnetohydrodynamics the mean electromotive force due to velocity and magnetic field fluctuations plays a crucial role. In general it consists of two parts, one independent of and another one proportional to the mean magnetic…

Solar and Stellar Astrophysics · Physics 2010-01-03 K. -H. Rädler , A. Brandenburg

We extend the standard two-scale theory of the turbulent dynamo coefficient $\alpha$ to include the nonlinear back reaction of the mean field $\bar B$ on the turbulence. We calculate the turbulent emf as a power series in $\bar B$, assuming…

Astrophysics · Physics 2009-10-31 George B. Field , Eric G. Blackman , Hongsong Chou

Magnetic helicity fluxes in turbulently driven alpha^2 dynamos are studied to demonstrate their ability to alleviate catastrophic quenching. A one-dimensional mean-field formalism is used to achieve magnetic Reynolds numbers of the order of…

Solar and Stellar Astrophysics · Physics 2012-07-17 Simon Candelaresi , Axel Brandenburg

Turbulence in the magnetized plasma is well understood to be the consequence of wave interactions. When the Hall effect is added to the minimum magnetohydrodynamics (MHD), the MHD waves become dispersive and different nonlinear interactions…

Plasma Physics · Physics 2026-02-19 Erik C. Hansen , Prerana Sharma , Swadesh M. Mahajan

Much work on turbulent three-dimensional dynamos has been done using triply periodic domains, in which there are no magnetic helicity fluxes. Here we present simulations where the turbulent intensity is still nearly homogeneous, but now…

Solar and Stellar Astrophysics · Physics 2019-02-20 A. Brandenburg