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We numerically evolve turbulence driven by the magnetorotational instability (MRI) in a 3D, unstratified shearing box and study its structure using two-point correlation functions. We confirm Fromang and Papaloizou's result that shearing…

Astrophysics of Galaxies · Physics 2011-02-11 Xiaoyue Guan , Charles F. Gammie , Jacob B. Simon , Bryan M. Johnson

We review numerical simulations of MHD turbulence. The last decade has witnessed fundamental advances both in the technical capabilities of direct numerical simulation, and in our understanding of key physical processes. Magnetic fields tap…

Astrophysics · Physics 2007-05-23 Steven A. Balbus , John F. Hawley

Measurements of solar wind turbulence reveal the ubiquity of discontinuities. In this study, we investigate how the discontinuities, especially rotational discontinuities (RDs), are formed in magnetohydrodynamic (MHD) turbulence. In a…

Solar and Stellar Astrophysics · Physics 2015-09-09 Liping Yang , Lei Zhang , Jiansen He , Chuanyi Tu , Linghua Wang , Eckart Marsch , Xin Wang , Shaohua Zhang , Xueshang Feng

We show that a large-scale, weak magnetic field threading a turbulent accretion disk tends to be advected inward, contrary to previous suggestions that it will be stopped by outward diffusion. The efficient inward transport is a consequence…

Astrophysics · Physics 2009-11-13 David M. Rothstein , Richard V. E. Lovelace

In spite of a large number of global three-dimensional (3D) magneto-hydrodynamical (MHD) simulations of accretion flows and jets being made recently, their astrophysical relevance for realistic situations is not well known. In order to…

Astrophysics · Physics 2009-11-10 K. Ohsuga , Y. Kato , S. Mineshige

Global 3-D magnetohydrodynamical simulations have been conducted to study magnetospheric accretion around stars with various spin rates. For slow rotators, characterized by a fastness parameter $\omega_s\lesssim 0.78$, the disk's inner edge…

Solar and Stellar Astrophysics · Physics 2025-02-26 Zhaohuan Zhu

A model for axisymmetric magnetized accretion flow is proposed. The dominant mechanism of energy dissipation is assumed to be the magnetic diffusivity due to turbulence in the accretion flow. In analogy to the advection-dominated accretion…

Astrophysics · Physics 2009-11-07 Mohsen Shadmehri

We study a Jupiter-mass planet formation for the first time in radiative magneto-hydrodynamics (MHD) simulations and compare it with pure hydrodynamical simulations, as well as to different isothermal configurations. We found that the…

Earth and Planetary Astrophysics · Physics 2023-05-31 Marco Cilibrasi , Mario Flock , Judit Szulágyi

Accretion disc turbulence is investigated in the framework of the shearing box approximation. The turbulence is either driven by the magneto-rotational instability or, in the non-magnetic case, by an explicit and artificial forcing term in…

Astrophysics · Physics 2008-11-26 Axel Brandenburg

By means of a nonlinear separation of the variables in the governing full set of the magnetohydrodynamic (MHD) equations for axisymmetric plasmas we analyse an exact model for magnetized and rotating outflows which are hotter and…

Astrophysics · Physics 2009-11-10 Christophe Sauty , Edoardo Trussoni , Kanaris Tsinganos

It is widely accepted that quasars and other active galactic nuclei (AGN) are powered by accretion of matter onto a central supermassive black hole. While numerical simulations have demonstrated the importance of magnetic fields in…

High Energy Astrophysical Phenomena · Physics 2009-11-13 Peter B. Dobbie , Zdenka Kuncic , Geoffrey V. Bicknell , Raquel Salmeron

This is the first in a series of papers that investigate the properties of accretion flows in the Kerr metric through three-dimensional, general relativistic magnetohydrodynamic simulations of tori with a near-Keplerian initial angular…

Astrophysics · Physics 2009-11-10 Jean-Pierre De Villiers , John F. Hawley , Julian H. Krolik

Thin viscous Keplerian accretion disks are considered asymptotically stable, even though they can show significant dynamic activity on short timescales. In this paper the dynamics of non-axisymmetric hydrodynamical disturbances of disks are…

High Energy Astrophysical Phenomena · Physics 2015-05-13 Paola Rebusco , Orkan M. Umurhan , Wlodek Kluzniak , Oded Regev

We investigate the dynamics of the accretion disks of young stars with fossil large-scale magnetic field. The author's magnetohydrodynamic (MHD) model of the accretion disks is generalized to consider the dynamical influence of the magnetic…

Solar and Stellar Astrophysics · Physics 2022-12-28 Sergey A. Khaibrakhmanov , Alexander E. Dudorov

We investigate the differences between an outflow in a highly-resistive accretion disk corona, and the results with smaller or vanishing resistivity. For the first time, we determine conditions at the base of a two-dimensional radially…

Solar and Stellar Astrophysics · Physics 2015-06-19 Miljenko Čemeljić , Nektarios Vlahakis , Kanaris Tsinganos

Recent numerical cosmological radiation-magnetohydrodynamic-thermochemical-star formation simulations have resolved the formation of quasar accretion disks with Eddington or super-Eddington accretion rates onto supermassive black holes…

We present the first 3D MHD study in spherical geometry of the non-linear dynamical evolution of magnetic flux tubes in a turbulent rotating convection zone. We study numerically the rise of magnetic toroidal flux ropes from the base of a…

Solar and Stellar Astrophysics · Physics 2011-02-11 Laurene Jouve , Allan Sacha Brun

Astrophysical disks are likely embedded in an ambient vertical magnetic field. This ambient field is known to drive magneto-rotational turbulence in the disk bulk but is also responsible for the launching of magnetized outflows at the…

High Energy Astrophysical Phenomena · Physics 2021-03-31 J. Jacquemin-Ide , G. Lesur , J. Ferreira

Absorption-line measurements of the circumgalactic medium (CGM) display a highly non-uniform distribution of lower ionization state species accompanied by more widespread higher ionization state material. This suggests that the CGM is a…

Astrophysics of Galaxies · Physics 2022-03-14 Edward Buie , Evan Scannapieco , G. Mark Voit

Accretion flows onto underluminous black holes, such as Sagittarius A* at the center of our galaxy, are dilute (mildly collisional to highly collisionless), optically thin, and radiatively inefficient. Therefore, the accretion properties of…

High Energy Astrophysical Phenomena · Physics 2015-05-28 Tanim Islam