English
Related papers

Related papers: Mean fields and fluctuations in compressible magne…

200 papers

Magnetic fields have been included in cosmological simulations of galaxy formation only recently, due to advances in numerical techniques and a better understanding of the galaxy formation physics. In this paper, we develop a new subgrid…

Astrophysics of Galaxies · Physics 2022-05-13 Yuankang Liu , Michael Kretschmer , Romain Teyssier

Mean-field galactic dynamo theory is the leading theory to explain the prevalence of regular magnetic fields in spiral galaxies, but its systematic comparison with observations is still incomplete and fragmentary. Here we compare…

Astrophysics of Galaxies · Physics 2016-12-14 Luke Chamandy , Anvar Shukurov , A. Russ Taylor

Galactic dynamo models have generally relied on input parameters that are very challenging to constrain. We address this problem by developing a model that uses observable quantities as input: the galaxy rotation curve, the surface…

Astrophysics of Galaxies · Physics 2024-04-04 Luke Chamandy , Rion Glenn Nazareth , Gayathri Santhosh

The physical nature of compressible turbulence is of fundamental importance in a variety of astrophysical settings. We present the first direct evidence that mean kinetic energy cascades conservatively beyond a transitional "conversion"…

Chaotic Dynamics · Physics 2015-05-30 Hussein Aluie , Shengtai Li , Hui Li

Using linear kinetic plasma theory the relation between electron density and magnetic field fluctuations for low-frequency plasma waves for Maxwellian background distribution functions of arbitrary temperatures in an uniform magnetic field…

Astrophysics · Physics 2007-05-23 R. Schlickeiser , I. Lerche

The role of supersonic turbulence in structuring the interstellar medium (ISM) remains an unsettled question. Here, this problem is investigated using a newexact law of compressible isothermal hydrodynamic turbulence, which involves…

Astrophysics of Galaxies · Physics 2023-03-14 Renaud Ferrand , Sébastien Galtier , Fouad Sahraoui , Christoph Federrath

Based on the Magnetospheric Multiscale (MMS) mission we look at magnetic field fluctuations in the Earth's magnetosheath. We apply the statistical analysis using a Fokker-Planck equation to investigate processes responsible for stochastic…

Plasma Physics · Physics 2023-09-14 Wiesław M. Macek , Dariusz Wójcik

Numerical simulations of magneto-convection have greatly expanded our understanding of stellar interiors and stellar magnetism. Recently, fully compressible hydrodynamical simulations of full-star models have demonstrated the feasibility of…

Solar and Stellar Astrophysics · Physics 2022-08-03 José R. Canivete Cuissa , Romain Teyssier

Solar wind turbulence is often perceived as weakly compressible and the density fluctuations remain poorly understood both theoretically and observationally. Compressible magnetohydrodynamic simulations provide useful insights into the…

Space Physics · Physics 2023-04-12 Senbei Du , Hui Li , Zhaoming Gan , Xiangrong Fu

Fluctuation dynamos provide a robust mechanism for amplifying weak seed magnetic fields in turbulent astrophysical plasmas. However, their behaviour in the highly compressible regimes characteristic of the interstellar medium remains…

Astrophysics of Galaxies · Physics 2026-02-18 Ameya Uday Nagdeo , Sharanya Sur , Bhargav Vaidya

Hydrostatic equilibrium of the multiphase interstellar medium in the solar vicinity is reconsidered, with the regular and turbulent magnetic fields treated separately. The regular magnetic field strength required to support the gas is…

Astrophysics · Physics 2009-11-06 Andrew Fletcher , Anvar Shukurov

The formation and evolution of a wide class of astrophysical objects is governed by turbulent, magnetized accretion disks. Understanding their secular dynamics is of primary importance. Apart from enabling mass accretion via the transport…

High Energy Astrophysical Phenomena · Physics 2015-09-16 Oliver Gressel , Martin E. Pessah

The possibility to derive an equation for the mean velocity field in turbulent flow by using classical statistical mechanics is investigated. An application of projection operator technique available in the literature is used for this…

Classical Physics · Physics 2007-05-23 J. Piest

The first complete estimation of the compressible energy cascade rate $|\varepsilon_\text{C}|$ at magnetohydrodynamic (MHD) and sub-ion scales is obtained in the Earth's magnetosheath using Magnetospheric MultiScale (MMS) spacecraft data…

We present full 2 Pi global 3-D stratified MHD simulations of accretion disks. We interpret our results in the context of proto-planetary disks. We investigate the turbulence driven by the magneto-rotational instability (MRI) using the…

Earth and Planetary Astrophysics · Physics 2015-05-27 M. Flock , N. Dzyurkevich , H. Klahr , N. J. Turner , Th. Henning

Mechanisms of nonhelical large-scale dynamos (shear-current dynamo and effect of homogeneous kinetic helicity fluctuations with zero mean) in a homogeneous turbulence with large-scale shear are discussed. We have found that the…

Astrophysics · Physics 2009-11-13 I. Rogachevskii , N. Kleeorin

The transition to intermittent mean--field dynamos is studied using numerical simulations of isotropic magnetohydrodynamic turbulence driven by a helical flow. The low-Prandtl number regime is investigated by keeping the kinematic viscosity…

Solar and Stellar Astrophysics · Physics 2015-05-13 Erico L. Rempel , Michael R. E. Proctor , Abraham C. -L. Chian

We formulate a coarse-graining approach to the dynamics of magnetohydrodynamic (MHD) fluids at a continuum of length-scales. In this methodology, effective equations are derived for the observable velocity and magnetic fields…

Solar and Stellar Astrophysics · Physics 2017-04-05 Hussein Aluie

Magnetic turbulence is classified as weak or strong based on the relative amplitude of the magnetic field fluctuations compared to the mean field. These two classifications have different energy transport properties. This study analyzes…

Astrophysics of Galaxies · Physics 2024-11-13 Evangelia Ntormousi , Loukas Vlahos , Anna Konstantinou , Heinz Isliker

Inhomogeneous polymers play an important role in various cellular processes, both in nature and in biotechnological applications. At finite temperatures, inhomogeneous polymers exhibit non-trivial thermal fluctuations. In a broader context,…

Statistical Mechanics · Physics 2017-02-02 Yohai Bar-Sinai , Eran Bouchbinder