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We investigate properties of the scale dependence and cross-scale transfer of kinetic energy in compressible three-dimensional hydrodynamic turbulence, by means of two direct numerical simulations of decaying turbulence with initial Mach…

Fluid Dynamics · Physics 2021-04-15 P. Hellinger , A. Verdini , S. Landi , E. Papini , L. Franci , L. Matteini

Intra Cluster Media (ICMs) located at galaxy clusters is in the state of hot, tenuous, magnetized, and highly ionized X-ray emitting plasmas. This overall collisionless, viscous, and conductive magnetohydrodynamic (MHD) turbulence in ICM is…

Plasma Physics · Physics 2015-07-14 Kiwan Park , Dongho Park

We present an MHD shell model suitable for computation of various energy fluxes of magnetohydrodynamic turbulence for very small and very large magnetic Prandtl numbers $\mathrm{Pm}$; such computations are inaccessible to direct numerical…

Fluid Dynamics · Physics 2016-09-21 Mahendra K. Verma , Rohit Kumar

We show that the self-similarity property of decaying turbulent non-helical magnetic fields is the same in all dimensions. It is shown that these fields produce an inverse transfer in all dimensions. It is also shown that this phenomenon in…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-17 P. Olesen

The sequence-dependent elasticity of double-helical DNA on a nm length scale can be captured by the rigid base-pair model, whose strains are the relative position and orientation of adjacent base-pairs. Corresponding elastic potentials have…

Biomolecules · Quantitative Biology 2013-05-29 Nils B. Becker , Ralf Everaers

The Kelvin-Helmholtz (KH) instability of a shear layer with an initially-uniform magnetic field in the direction of flow is studied in the framework of 2D incompressible magnetohydrodynamics with finite resistivity and viscosity using…

Plasma Physics · Physics 2021-03-15 A. E. Fraser , P. W. Terry , E. G. Zweibel , M. J. Pueschel , J. M. Schroeder

3D kinetic-scale turbulence is studied numerically in the regime where electrons are strongly magnetized (the ratio of plasma species pressure to magnetic pressure is $\beta_e=0.1$ for electrons and $\beta_i=1$ for ions). Such a regime is…

Plasma Physics · Physics 2023-07-05 Cristian Vega , Vadim Roytershteyn , Gian Luca Delzanno , Stanislav Boldyrev

We review our current understanding of galactic dynamo theory, paying particular attention to numerical simulations both of the mean-field equations and the original three-dimensional equations relevant to describing the magnetic field…

Astrophysics of Galaxies · Physics 2014-12-12 Axel Brandenburg

In the absence of an active dynamo, purely poloidal magnetic field configurations are unstable to large-scale dynamical perturbations, and decay via reconnection on an Alfvenic timescale. Nevertheless, a number of classes of dynamo-free…

Astrophysics · Physics 2009-11-13 Avery E. Broderick , Ramesh Narayan

Small-scale fluctuating magnetic fields of order $n$G are observed in supernova shocks and galaxy clusters, where its amplification is likely caused by the Biermann battery mechanism. However, these fields cannot be amplified further…

Astrophysics of Galaxies · Physics 2023-02-22 Justin Kin Jun Hew , Christoph Federrath

We have extended our previous mean-field galactic dynamo model which included algebraic and dynamic alpha nonlinearities (Kleeorin et al., A&A, v. 387, 453, 2002), to include also a quenching of turbulent diffusivity. We readily obtain…

Astrophysics · Physics 2014-10-13 N. Kleeorin , D. Moss , I. Rogachevskii , D. Sokoloff

Investigations of the inverse cascade of magnetic helicity are conducted with pseudospectral, three-dimensional direct numerical simulations of forced and decaying incompressible magnetohydrodynamic turbulence. The high-resolution…

Solar and Stellar Astrophysics · Physics 2013-09-23 Wolf-Christian Müller , Shiva Kumar. Malapaka

We derive exact scaling laws for a three-dimensional incompressible helical two-fluid plasma, without the assumption of isotropy. For each ideal invariant of the two-fluid model, i.e. the total energy, the electron helicity and the proton…

Plasma Physics · Physics 2017-01-17 Nahuel Andrés , Sebastien Galtier , Fouad Sahraoui

We study the evolution of kinetic and magnetic energy spectra in magnetohydrodynamic flows in the presence of strong cross helicity. For forced turbulence, we find weak inverse transfer of kinetic energy toward the smallest wavenumber. This…

Fluid Dynamics · Physics 2019-02-20 Axel Brandenburg , Sean Oughton

Nonlinear mean-field models of the solar dynamo show long-term variability, which may be relevant to different states of activity inferred from long-term radiocarbon data. This paper is aimed to probe the dynamo hysteresis predicted by the…

Solar and Stellar Astrophysics · Physics 2015-04-24 Bidya Binay Karak , Leonid L. Kitchatinov , Axel Brandenburg

It has been recently shown numerically that there exists an inverse transfer of magnetic energy in decaying, nonhelical, magnetically dominated, magnetohydrodynamic turbulence in 3-dimensions (3D). We suggest that magnetic reconnection is…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-23 Pallavi Bhat , Muni Zhou , Nuno F. Loureiro

We live in an age in which high-performance computing is transforming the way we do science. Previously intractable problems are now becoming accessible by means of increasingly realistic numerical simulations. One of the most enduring and…

We study the generation of large scale primordial magnetic fields by a cosmological phase transition during the radiation dominated era. The setting is a theory of N charged scalar fields coupled to an abelian gauge field, that undergoes a…

Astrophysics · Physics 2007-05-23 D. Boyanovsky , H. J. de Vega , M. Simionato

High Reynolds number isotropic magneto-hydro-dynamic turbulence in the presence of large scale magnetic fields is investigated as a function of the magnetic field strength. For a variety of flow configurations the energy dissipation rate…

Fluid Dynamics · Physics 2012-09-20 Alexandros Alexakis

We perform direct numerical simulations of three-dimensional freely decaying magnetohydrodynamic (MHD) turbulence. For helical magnetic fields an inverse cascade effect is observed in which power is transfered from smaller scales to larger…

Astrophysics · Physics 2009-10-31 Mattias Christensson , Mark Hindmarsh , Axel Brandenburg