Evolution of a stochastically homogeneous magnetic field advected by an incompressible turbulent flow with large magnetic Prandtl numbers is considered at scales smaller than the Kolmogorov viscous scale. It is shown ...
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Evolution of a stochastically homogeneous magnetic field advected by an incompressible turbulent flow with large magnetic Prandtl numbers is considered at scales smaller than the Kolmogorov viscous scale. It is shown that, despite the unlimited growth of the magnetic field, its feedback on the fluid's dynamics remains negligibly small. Copyright (C) 2020 EPLA
Magnetohydrodynamics (MHD) describes the behavior of a charged fluid in a strong magnetic field. One way to analyze noncommutativity in MHD is by considering the result of an eternal magnetic field on noncommutative (...
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Magnetohydrodynamics (MHD) describes the behavior of a charged fluid in a strong magnetic field. One way to analyze noncommutativity in MHD is by considering the result of an eternal magnetic field on noncommutative (NC) photon dynamics. In this paper we have introduced a new MHD Lagrangian and we have obtained the Navier-Stokes MHD equation. We have constructed a NC algebra for the dynamical MHD variables and analyzed the mechanical energy variation rate together with the coupling between the vortex and magnetic field. We have calculated the rate of variation of circulation and analyzed each term. We have seen that these terms are connected to noncommutativity which can act as a source of vorticity. Copyright (C) EPLA, 2020
Statistical moments of magnetic field in a viscous range of turbulence are calculated for arbitrary initial conditions. It is shown that the evolution of magnetic field in the case of finite initial distribution in a ...
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Statistical moments of magnetic field in a viscous range of turbulence are calculated for arbitrary initial conditions. It is shown that the evolution of magnetic field in the case of finite initial distribution in a linear velocity field consists of two or three consecutive regimes: exponential growth is followed by exponential decay. This solves the apparent contradiction between "anti-dynamo" theorems and growth of magnetic field with statistically homogeneous initial conditions.
In this letter we attempt to trace back the origin of quantum uncertainty. We show that the Schrodinger equation can be mapped into the inviscid Favre-Reynolds turbulence equations of classical compressible fluids, al...
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In this letter we attempt to trace back the origin of quantum uncertainty. We show that the Schrodinger equation can be mapped into the inviscid Favre-Reynolds turbulence equations of classical compressible fluids, albeit in zero temperature. Under this mapping the probability density function becomes the Reynolds time mean density of the fluid, the real and the imaginary parts of the momentum become the mean and turbulent root-mean-square velocities, respectively, where the latter obeys the first Fick law of diffusion and saturates the lower bound of the uncertainty principle. The mean pressure is proportional to the divergence of the turbulent mass flux and is the source for stochasticity. The roles of the pressure gradient force and the Reynolds stress tensor convergence, under this mapping, are illustrated in two well-known systems, namely, the 1s orbital hydrogen atom and the 1D dynamic Gaussian wavepacket. Finally, we analyze within an independent part of the letter, a conjecture according to which this pressure results from vacuum fluctuations at the zero-point energy, mediated by random collisions of the particle with virtual photons. This suggests that the typical turbulent eddy is of the size of the Compton wavelength corresponding to a Reynolds averaging time scale which is twice the Zitterbewegung period. Moreover, according to this interpretation the quantized characteristics of the particle result from interactions with virtual photons. Copyright (C) EPLA, 2018
The origin of magnetic fields in the universe still remains unknown and constitutes one of the most intriguing questions in astronomy and astrophysics. Their significance is enormous since they have a strong influence...
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The origin of magnetic fields in the universe still remains unknown and constitutes one of the most intriguing questions in astronomy and astrophysics. Their significance is enormous since they have a strong influence on many astrophysical phenomena. In regards of this motivation, theoretical models of galactic disks with sources of magnetic field may contribute to understand the physics behind them. Inspired by this, we present a new family of analytical models for thin disks composed by magnetized material. The solutions are axially symmetric, conformastatic and are obtained by solving the Einstein-Maxwell Field Equations for continuum media without the test field approximation, and assuming that the sources are razor-thin disk of magnetically polarized matter. We find analytical expressions for the surface energy density, the pressure, the polarization vector, the electromagnetic fields, the mass and the rotational velocity for circular orbits, for two particular solutions. In each case, the energy-momentum tensor agrees with the energy conditions and also the convergence of the mass for all the solutions is proved. Since the solutions are well-behaved, they may be used to model astrophysical thin disks, and also may contribute as initial data in numerical simulations. In addition, the process to obtain the solutions is described in detail, which may be used as a guide to find solutions with magnetized material in general Relativity.
Advanced fluiddynamics of the Environment- Micro-Scale Basis of Seepage Flow, theory of Homogenization by Chiang C. Mei; published by *** on Behalf of the Author
Advanced fluiddynamics of the Environment- Micro-Scale Basis of Seepage Flow, theory of Homogenization by Chiang C. Mei; published by *** on Behalf of the Author
Nowadays, the magnetic and radiation fields are very important to understand the matter accretion into compact objects, the dynamics of binary systems, the equilibrium configurations of neutron stars, the photon diffu...
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Nowadays, the magnetic and radiation fields are very important to understand the matter accretion into compact objects, the dynamics of binary systems, the equilibrium configurations of neutron stars, the photon diffusion, etc. The energy and the momentum associated with these fields, along with the matter one, need to satisfy some conditions that guarantee an appropriate physical behavior of the source and its gravitational field. Based on this fact, we present the energy conditions for a perfect fluid with magnetic and radiation field, in which the radiation part of the energy-momentum tensor is assumed to be approximately isotropic, in accordance with the optically thick regime. In order to find these conditions, the stress tensor of the system is written in an orthonormal basis in which it becomes diagonal, and the energy conditions are computed through contractions of the energy-momentum tensor with the four velocity vector of an arbitrary observer. Finally, the conditions for a magnetized fluid are presented as a particular case in which the radiation contribution is zero.
It is extremely uncommon to be able to predict the velocity profile of a turbulent flow. In two-dimensional flows, atmosphere dynamics, and plasma physics, large-scale coherent jets are created through inverse energy ...
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It is extremely uncommon to be able to predict the velocity profile of a turbulent flow. In two-dimensional flows, atmosphere dynamics, and plasma physics, large-scale coherent jets are created through inverse energy transfers from small scales to the largest scales of the flow. We prove that in the limits of vanishing energy injection, vanishing friction, and small-scale forcing, the velocity profile of a jet obeys an equation independently of the details of the forcing. We find another general relation for the maximal curvature of a jet and we give strong arguments to support the existence of a hydrodynamic instability at the point with minimal jet velocity. Those results are the first computations of Reynolds stresses and self-consistent velocity profiles from the turbulent dynamics, and the first consistent analytic theory of zonal jets in barotropic turbulence. Copyright (C) EPLA, 2017
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