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Turbulent thermal diffusion is a combined effect of the temperature stratified turbulence and inertia of small particles. It causes the appearance of a non-diffusive turbulent flux of particles in the direction of the turbulent heat flux.…

Fluid Dynamics · Physics 2018-05-24 G. Amir , N. Bar , A. Eidelman , T. Elperin , N. Kleeorin , I. Rogachevskii

The emergence of large-scale magnetic fields observed in the diffuse interstellar medium is explained by a turbulent dynamo. The underlying transport coefficients have previously been extracted from numerical simulations. So far, this was…

Astrophysics of Galaxies · Physics 2015-06-11 Oliver Gressel , Abhijit Bendre , Detlef Elstner

Using the test-field method for nearly irrotational turbulence driven by spherical expansion waves it is shown that the turbulent magnetic diffusivity increases with magnetic Reynolds numbers. Its value levels off at several times the rms…

Astrophysics of Galaxies · Physics 2010-11-05 Axel Brandenburg , Fabio Del Sordo

Accretion disks in which angular momentum transport is dominated by the magnetorotational instability (MRI) can also possess additional, purely hydrodynamic, drivers of turbulence. Even when the hydrodynamic processes, on their own,…

Astrophysics · Physics 2009-11-13 Jared C. Workman , Philip J. Armitage

We analyze a suite of global magnetohydrodynamic (MHD) accretion disk simulations in order to determine whether scaling laws for turbulence driven by the magnetorotational instability, discovered via local shearing box studies, are globally…

High Energy Astrophysical Phenomena · Physics 2015-05-18 Kareem A. Sorathia , Christopher S. Reynolds , Philip J. Armitage

Recent numerical analysis of Keplerian disk formation in turbulent, magnetized cloud cores by Santos-Lima, de Gouveia Dal Pino, & Lazarian (2012) demonstrated that reconnection diffusion is an efficient process to remove the magnetic flux…

Astrophysics of Galaxies · Physics 2015-06-12 R. Santos-Lima , E. M. de Gouveia Dal Pino , A. Lazarian

The effect of a possible hydrodynamical wind on the nature of hot accretion disk solutions is studied. It is found that the advection dominated branch, in the presence of a wind, maintains the self-similar solution for the disk structure…

Astrophysics · Physics 2009-11-06 Ranjeev Misra , Ronald E. Taam

We investigate fluid motions near the midplane of vertically stratified accretion disks with highly resistive midplanes. In such disks, the magnetorotational instability drives turbulence in thin layers surrounding a resistive, stable dead…

Earth and Planetary Astrophysics · Physics 2014-11-20 Jeffrey S. Oishi , Mordecai-Mark Mac Low

The fundamental assumptions of the adiabatic theory do not apply in presence of sharp field gradients as well as in presence of well developed magnetohydrodynamic turbulence. For this reason in such conditions the magnetic moment $\mu$ is…

Space Physics · Physics 2015-06-04 S. Dalena , A. Greco , A. F. Rappazzo , R. L. Mace , W. H. Matthaeus

Rapidly rotating convection-driven dynamos are investigated under different kinematic and magnetic boundary conditions using DNS. At a fixed rotation rate, represented by the Ekman number $E=5\times10^{-7}$, the thermal forcing is varied…

Fluid Dynamics · Physics 2022-11-23 Souvik Naskar , Anikesh Pal

We consider the effect of vertical outflows on the mean-field dynamo in a thin disk. These outflows could be due to winds or magnetic buoyancy. We analyse both two-dimensional finite-difference numerical solutions of the axisymmetric dynamo…

Astrophysics · Physics 2009-10-31 A. Bardou , B. v. Rekowski , W. Dobler , A. Brandenburg , A. Shukurov

The magnetic dissipative droplet is a strongly nonlinear wave structure that can be stabilized in a thin film ferromagnet exhibiting perpendicular magnetic anisotropy by use of spin transfer torque. These structures have been observed…

Mesoscale and Nanoscale Physics · Physics 2016-04-12 P. Wills , E. Iacocca , M. A. Hoefer

We study the local thermal stability of thin accretion disks. We present a full stability analysis in the presence of a magnetic field and more importantly wind. For wind, we use a general model suitable for adequately describing several…

Astrophysics of Galaxies · Physics 2020-01-08 Asiyeh Habibi , Shahram Abbassi

Given the large anisotropy of transport processes in magnetized plasmas, the magnetic field structure can strongly impact heat diffusion: magnetic surfaces and cantori form barriers to transport while chaotic layers and island structures…

Plasma Physics · Physics 2022-02-08 Elizabeth J. Paul , Stuart R. Hudson , Per Helander

Hot accretion flows contain collisionless plasmas that are believed to be capable of accelerating particles to very high energies, as a result of turbulence generated by the magnetorotational instability (MRI). We conduct unstratified…

High Energy Astrophysical Phenomena · Physics 2021-07-14 Xiaochen Sun , Xue-Ning Bai

To explore the combined effects of partial thermal stable stratification and magnetic back-reaction within Earth's tangent cylinder, we study the onset of magnetoconvection in an infinite plane layer subject to horizontal magnetic field…

Fluid Dynamics · Physics 2026-02-10 Tirtharaj Barman , Arpan Das , Swarandeep Sahoo

In dilute astrophysical plasmas, the collisional mean free path of a particle can exceed its Larmor radius. Under these conditions, the thermal conductivity and viscosity of the plasma can be dramatically altered. This alteration allows…

Astrophysics · Physics 2009-11-11 Tanim Islam , Steven Balbus

We solved the set of two-dimensional magnetohydrodynamic (MHD) equations for optically thin black hole accretion flows incorporating toroidal component of magnetic field. Following global and local MHD simulations of black hole accretion…

High Energy Astrophysical Phenomena · Physics 2018-01-31 Fatemeh Zahra Zeraatgari , Amin Mosallanezhad , Shahram Abbassi , Ye-Fei Yuan

An effect of rotation on a developed turbulent stratified convection is studied. Dependencies of the hydrodynamic helicity, the alpha-tensor and the effective drift velocity of the mean magnetic field on the rate of rotation and an…

Astrophysics · Physics 2009-11-07 N. Kleeorin , I. Rogachevskii

Abstract: Assuming that the numerical diffusivity triggered by violations of the force-free electrodynamics constraints is a proxy for the physical resistivity, we examine its impact on the overall dynamics of force-free aligned pulsar…

High Energy Astrophysical Phenomena · Physics 2021-10-13 J. F. Mahlmann , M. A. Aloy