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Magnetized plasmas with equilibrium density gradients support drift-wave turbulence, which is often regulated by self-generated zonal flows. In this work, we experimentally examine the effect of increasing the magnetic field on turbulence…

Following the wellknown spacetime decomposition technique as applied to (d+1) dimensions we write down the equations of magnetohydrodynamics (MHD) in a spatially at generalised FRW universe. Assuming an equation of state for the background…

General Relativity and Quantum Cosmology · Physics 2009-09-28 D. Panigrahi , Ajanta Das , S. Chatterjee

It is shown that gravitating magnetic fields affect the evolution of curvature perturbations in a way that is reminiscent of a pristine non-adiabatic pressure fluctuation. The gauge-invariant evolution of curvature perturbations is used to…

Astrophysics · Physics 2008-11-26 Massimo Giovannini

Nonlinear relations among frequencies and phases in modulational instability of circularly polarized Alfven waves are discussed, within the context of one dimensional, dissipation-less, unforced fluid system. We show that generation of…

Plasma Physics · Physics 2020-01-29 Yasuhiro Nariyuki , Tohru Hada

Plasma turbulence occurs ubiquitously in space and astrophysical plasmas, mediating the nonlinear transfer of energy from large-scale electromagnetic fields and plasma flows to small scales at which the energy may be ultimately converted to…

Plasma Physics · Physics 2018-02-28 Gregory G. Howes , Sofiane Bourouaine

We present results from two-dimensional numerical simulations of a supersonic turbulent flow in the plane of the galactic disk, incorporating shear, thresholded and discrete star formation (SF), self-gravity, rotation and magnetic fields. A…

Astrophysics · Physics 2009-10-28 T. Passot , E. Vazquez-Semadeni , A. Pouquet

Spatial intermittency in decaying kinetic Alfven wave turbulence is investigated to determine if it produces non Gaussian density fluctuations in the interstellar medium. Non Gaussian density fluctuations have been inferred from pulsar…

Astrophysics · Physics 2011-02-11 P. W. Terry , K. W. Smith

It is widely accepted in the MHD turbulence community that the nonlinear cascade of wave energy requires counter-propagating Alfv\'enic wave-packets, along some mean magnetic field. This fact is an obvious outcome of the MHD equations under…

Solar and Stellar Astrophysics · Physics 2019-09-11 N. Magyar , T. Van Doorsselaere , M. Goossens

In this paper, results of 2.5-dimensional magnetohydrodynamical simulations are reported for the magnetic reconnection of non-perfectly antiparallel magnetic fields. The magnetic field has a component perpendicular to the computational…

Solar and Stellar Astrophysics · Physics 2015-05-18 Hiromitsu Kigure , Kunio Takahashi , Kazunari Shibata , Takaaki Yokoyama , Satoshi Nozawa

Magnetic fields appear to be ubiquitous in astrophysical environments. Their existence in the intracluster medium is established through observations of synchrotron emission and Faraday rotation. On the other hand, the nature of magnetic…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Dongsu Ryu , Dominik R. G. Schleicher , Rudolf A. Treumann , Christos G. Tsagas , Lawrence M. Widrow

Using simulations of slowly rotating stratified turbulence, we show that the alpha effect responsible for the generation of astrophysical magnetic fields is proportional to the logarithmic gradient of kinetic energy density rather than that…

Solar and Stellar Astrophysics · Physics 2012-12-27 A. Brandenburg , O. Gressel , P. J. Käpylä , N. Kleeorin , M. J. Mantere , I. Rogachevskii

Magnetic field fluctuations in MHD turbulence can be viewed as current sheets that are progressively more anisotropic at smaller scales. As suggested by Loureiro & Boldyrev (2017) and Mallet et al (2017), below a certain critical thickness…

Plasma Physics · Physics 2017-08-09 Stanislav Boldyrev , Nuno F. Loureiro

We study compressible MHD turbulence, which holds key to many astrophysical processes, including star formation and cosmic ray propagation. To account for the variations of the magnetic field in the strongly turbulent fluid we use wavelet…

Astrophysics of Galaxies · Physics 2015-05-18 Grzegorz Kowal , Alex Lazarian

We study the generation of magnetic fields during preheating within an scenario of hybrid inflation at the electroweak (EW) scale. We find that the non-perturbative and strongly out-of-equilibrium process of magnetic field production occurs…

High Energy Physics - Phenomenology · Physics 2008-11-26 Andres Diaz-Gil , Juan Garcia-Bellido , Margarita Garcia Perez , Antonio Gonzalez-Arroyo

Generation of large-scale magnetic fields in inflationary cosmology is studied in teleparallelism, where instead of the scalar curvature in general relativity, the torsion scalar describes the gravity theory. In particular, we investigate a…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-26 Kazuharu Bamba , Chao-Qiang Geng , Ling-Wei Luo

The evolution of Alfven turbulence due to three-wave interactions is discussed using kinetic theory for a collisionless, thermal plasma. There are three low-frequency modes, analogous to the three modes of compressible MHD. When only Alfven…

Astrophysics · Physics 2009-11-11 Q. Luo , D. B. Melrose

Magnetic fluctuations generated by a tangling of the mean magnetic field by velocity fluctuations are studied in a developed turbulent convection with large magnetic Reynolds numbers. We show that the energy of magnetic fluctuations depends…

Astrophysics · Physics 2008-11-26 I. Rogachevskii , N. Kleeorin

We present numerical simulations and explore scalings and anisotropy of compressible magnetohydrodynamic (MHD) turbulence. Our study covers both gas pressure dominated (high beta) and magnetically dominated (low beta) plasmas at different…

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

We investigate the steepening of the magnetic fluctuation power law spectra observed in the inner solar wind for frequencies higher than 0.5 Hz. This high frequency part of the spectrum may be attributed to dispersive nonlinear processes.…

Space Physics · Physics 2009-11-13 S. Galtier

We investigate numerically the dynamics of two-dimensional Euler and ideal magnetohydrodynamics (MHD) flows in systems with a finite number of modes, up to $4096^2$, for which several quadratic invariants are preserved by the truncation and…

Chaotic Dynamics · Physics 2015-05-20 Giorgio Krstulovic , Marc-Etienne Brachet , Annick Pouquet