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We consider the linear stability to three-dimensional perturbations of two-dimensional nonlinear magnetohydrodynamic basic states obtained from a specified forcing function in the presence of an imposed initially uniform magnetic field of…

Fluid Dynamics · Physics 2009-06-17 D. W. Hughes , M. R. E. Proctor

An update is given on the current status of solar and stellar dynamos. At present, it is still unclear why stellar cycle frequencies increase with rotation frequency in such a way that their ratio increases with stellar activity. The…

Solar and Stellar Astrophysics · Physics 2015-06-15 Axel Brandenburg

The magnetorotational instability (MRI) triggers turbulence and enables outward transport of angular momentum in hydrodynamically stable accretion discs. By using the WKB approximation and methods of singular function theory, we resolve two…

Solar and Stellar Astrophysics · Physics 2015-03-19 Oleg N. Kirillov , Frank Stefani

The classical Rayleigh-B\'{e}nard convection (RBC) system is known to exhibit either subcritical or supercritical transition to convection in the presence or absence of rotation and/or magnetic field. However, the simultaneous exhibition of…

Fluid Dynamics · Physics 2020-08-26 Ankan Banerjee , Manojit Ghosh , Pinaki Pal

We study the onset of magnetoconvection between two infinite horizontal planes subject to a vertical magnetic field aligned with background rotation. In order to gain insight into the convection taking place in the Earth's tangent cylinder…

Fluid Dynamics · Physics 2014-07-04 Kélig Aujogue , Alban Pothérat , Binod Sreenivasan

A model for three-dimensional Rayleigh-B\'{e}nard convection in low-Prandtl-number fluids near onset with rigid horizontal boundaries in the presence of a uniform vertical magnetic field is constructed and analyzed in detail. The kinetic…

Fluid Dynamics · Physics 2015-10-28 Arnab Basak , Krishna Kumar

The discovery of the first binary neutron star merger, GW170817, has spawned a plethora of global numerical relativity simulations. These simulations are often ideal (with dissipation determined by the grid) and/or axisymmetric (invoking ad…

High Energy Astrophysical Phenomena · Physics 2024-04-10 Loren E. Held , George Mamatsashvili , Martin E. Pessah

The reduced density matrices (RDMs) are calculated in the thermodynamic limit for the Chern-Simons non-relativistic particle system and Maxwell-Boltzmann (MB) statistics. It is established that they are zero outside of a diagonal and…

Statistical Mechanics · Physics 2016-08-31 W. Skrypnik

We study the scaling properties of heat transfer $Nu$ in turbulent thermal convection at large Prandtl number $Pr$ using a quasi-linear theory. We show that two regimes arise, depending on the Reynolds number $Re$. At low Reynolds number,…

Chaotic Dynamics · Physics 2015-05-28 B. Dubrulle

Variational turbulence is among the few approaches providing rigorous results in turbulence. In addition, it addresses a question of direct practical interest, namely the rate of energy dissipation. Unfortunately, only an upper bound is…

Fluid Dynamics · Physics 2009-10-28 Thierry Alboussiere

Convective turbulence in a Rayleigh Benard system has shown a marked reluctance to exhibit clear scaling in the energy or entropy spectrum. The recent numerical simulation of Pandey, Verma and Mishra has shown significantly better evidence…

Fluid Dynamics · Physics 2014-06-10 Jayanta Kumar Bhattacharjee

The dynamo effect is the most popular candidate to explain the non-primordial magnetic fields of astrophysical objects. Although many systematic studies of parameters have already been made to determine the different dynamical regimes…

Fluid Dynamics · Physics 2020-07-14 Mélissa D. Menu , Ludovic Petitdemange , Sébastien Galtier

With a non local shell model of magnetohydrodynamic turbulence we investigate numerically the turbulent dynamo action for low and high magnetic Prandtl numbers ($Pm$). The results obtained in the kinematic regime and along the way to dynamo…

Astrophysics · Physics 2009-11-13 Rodion Stepanov , Franck Plunian

Understanding the numerical dependencies that act on the galactic dynamo is a crucial step in determining what resolution and what conditions are required to properly capture the magnetic fields observed in galaxies. Here, we present an…

Astrophysics of Galaxies · Physics 2023-05-03 Robert Wissing , Sijing Shen

Generation of magnetic field energy, without mean field generation, is studied. Isotropic mirror-symmetric turbulence of a conducting fluid amplifies the energy of small-scale magnetic perturbations if the magnetic Reynolds number is high,…

Astrophysics · Physics 2008-11-26 A. Gruzinov , S. Cowley , R. Sudan

Rotational scaling relationships are examined for the degree of equipartition between magnetic and kinetic energies in stellar convection zones. These scaling relationships are approached from two paradigms, with first a glance at scaling…

Solar and Stellar Astrophysics · Physics 2022-11-30 K. ~C. Augustson , A. ~S. Brun , J. Toomre

We consider a randomly forced particle moving in a finite region, which rebounds inelastically with coefficient of restitution r on collision with the boundaries. We show that there is a transition at a critical value of r, r_c\equiv…

Statistical Mechanics · Physics 2009-10-31 Stephen J. Cornell , Michael R. Swift , Alan J. Bray

In presence of an externally supported, mean magnetic field a turbulent, conducting medium, such as plasma, becomes anisotropic. This mean magnetic field, which is separate from the fluctuating, turbulent part of the magnetic field, has…

Plasma Physics · Physics 2018-12-07 Riddhi Bandyopadhyay , S. Oughton , M. Wan , W. H. Matthaeus , R. Chhiber , T. N. Parashar

We investigate the phenomenon of drag reduction in a viscoelastic fluid model of dilute polymer solutions. By means of direct numerical simulations of the three-dimensional turbulent Kolmogorov flow we show that drag reduction takes place…

Chaotic Dynamics · Physics 2016-09-08 Guido Boffetta , Antonio Celani , Andrea Mazzino

A numerical study of convection with stress-free boundary conditions in the presence of an imposed magnetic field that is tilted with respect to the direction of gravity is carried out in the limit of small magnetic Reynolds number. The…

Fluid Dynamics · Physics 2021-11-03 Justin A. Nicoski , Ming Yan , Michael A. Calkins