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Related papers: Modelling MHD accretion-ejection - from the launch…

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In this paper, steady-state MHD calculations of non-relativistic magnetized accretion discs driving jets are presented. For the first time, an energy equation describing the effects of entropy generation along streamlines is included. Using…

Astrophysics · Physics 2007-05-23 Fabien Casse , Jonathan Ferreira

We present a 3-D ideal MHD simulation of magnetospheric accretion onto a non-rotating star. The accretion process unfolds with intricate 3-D structures driven by various mechanisms. First, the disc develops filaments at the magnetospheric…

Solar and Stellar Astrophysics · Physics 2023-12-18 Zhaohuan Zhu , James M. Stone , Nuria Calvet

Axisymmetric resistive MHD simulations for radially self-similar initial conditions are performed, using the NIRVANA code. The magnetic diffusivity could occur in outflows above an accretion disk, being transferred from the underlying disk…

Solar and Stellar Astrophysics · Physics 2015-05-13 Miljenko Cemeljic , Jose Gracia , Nektarios Vlahakis , Kanaris Tsinganos

We perform axisymmetric relativistic magnetohydrodynamic (MHD) simulations to investigate the acceleration and collimation of jets and outflows from disks around compact objects. The fiducial disk surface (respectively a slow disk wind) is…

High Energy Astrophysical Phenomena · Physics 2014-11-20 O. Porth , C. Fendt

This is a doctorate level lecture on the physics of accretion discs driving magnetically self-confined jets, usually referred to in the literature as disc winds. I will first review the governing magnetohydrodynamic equations and then…

Astrophysics · Physics 2008-11-26 Jonathan Ferreira

The ejection of matter in the close vicinity of a young stellar object is investigated, treating the accretion disk as a gravitationally bound reservoir of matter. By solving the resistive MHD equations in 2D axisymmetry using our version…

Solar and Stellar Astrophysics · Physics 2024-05-01 Miljenko Čemeljić , Hsien Shang , Tzu-Yang Chiang

The acceleration of an outflow along inclined magnetic field lines emanating from an accretion disc can be studied in the local approximation, as employed in the computational model known as the shearing box. By including the slow…

Solar and Stellar Astrophysics · Physics 2015-06-04 Gordon I. Ogilvie

Astrophysical jets are launched from strongly magnetized systems that host an accretion disk surrounding a central object. Here we address the question how to generate the accretion disk magnetization and field structure required for jet…

High Energy Astrophysical Phenomena · Physics 2020-09-07 Giancarlo Mattia , Christian Fendt

The inward flow of matter through accretion disks is driven by MHD turbulence. Global general relativistic MHD simulations shed quantitative light on this process, revealing a number of aspects of accretion previously unrecognized. Among…

Astrophysics · Physics 2008-11-26 J. H. Krolik , J. F. Hawley

The theory of jet emitting disks (JEDs) provides a mathematical framework for a self-consistent treatment of steady-state accretion and ejection. A large-scale vertical magnetic field threads the accretion disk where magnetic turbulence…

High Energy Astrophysical Phenomena · Physics 2024-12-11 N. Zimniak , J. Ferreira , J. Jacquemin-Ide

We report new global ideal MHD simulations for thin accretion disks (with thermal scale height H/R=0.1 and 0.05) threaded by net vertical magnetic fields. Our computations span three orders of magnitude in radius, extend all the way to the…

Earth and Planetary Astrophysics · Physics 2018-04-25 Zhaohuan Zhu , James M. Stone

We present the first-ever simulations of non-ideal magnetohydrodynamical (MHD) stellar winds coupled with disc-driven jets where the resistive and viscous accretion disc is self-consistently described. The transmagnetosonic, collimated MHD…

Astrophysics · Physics 2008-11-26 Fabien Casse , Zakaria Meliani , C. Sauty

We present the results of nine simulations of radiatively-inefficient magnetically arrested disks (MADs) across different values of the black hole spin parameter $a_*$: $-0.9$, $-0.7$, $-0.5$, $-0.3$, 0, 0.3, 0.5, 0.7, and 0.9. Each…

High Energy Astrophysical Phenomena · Physics 2022-02-16 Ramesh Narayan , Andrew Chael , Koushik Chatterjee , Angelo Ricarte , Brandon Curd

We review recent axisymmetric and three-dimensional (3D) magnetohydrodynamic (MHD) numerical simulations of magnetospheric accretion, plasma-field interaction and outflows from the disk-magnetosphere boundary.

Solar and Stellar Astrophysics · Physics 2015-06-17 M. M. Romanova , R. V. E. Lovelace , M. Bachetti , A. A. Blinova , A. V. Koldoba , R. Kurosawa , P. S. Lii , G. V. Ustyugova

We have performed 3-D numerical magnetohydrodynamic (MHD) jet experiments to study the instabilities associated with strongly toroidal magnetic fields and determine if such magnetic configurations in jets are as unstable as similar…

Astrophysics · Physics 2007-05-23 F. Thomsen , A. Nordlund

Global three dimensional magnetohydrodynamic (MHD) simulations of turbulent accretion disks are presented which start from fully equilibrium initial conditions in which the magnetic forces are accounted for and the induction equation is…

High Energy Astrophysical Phenomena · Physics 2015-06-12 E. R. Parkin , G. V. Bicknell

We present 3D general relativistic magnetohydrodynamic(GRMHD) simulations of zero angular momentum accretion around a rapidly rotating black hole, modified by the presence of initially uniform magnetic fields. We consider serveral angles…

High Energy Astrophysical Phenomena · Physics 2021-02-17 Sean M. Ressler , Eliot Quataert , Christopher J. White , Omer Blaes

(Abridged) We report results of three dimensional MHD simulations of global accretion disks threaded with weak vertical magnetic fields. We perform the simulations in the spherical coordinates with different temperature profiles and…

Earth and Planetary Astrophysics · Physics 2015-06-17 Takeru K. Suzuki , Shu-ichiro Inutsuka

Aims. A realistic model of magnetic linkage between a central object and its accretion disk is a prerequisite for understanding the spin history of stars and stellar remnants. To this end, we aim to provide an analytic model in agreement…

Solar and Stellar Astrophysics · Physics 2023-10-04 Miljenko Čemeljić , Włodek Kluźniak , Varadarajan Parthasarathy

Using axisymmetric MHD simulations we investigate how the overall jet formation is affected by a variation in the disk magnetic flux profile and/or the existence of a central stellar magnetosphere. Our simulations evolve from an initial,…

Astrophysics · Physics 2015-05-13 Christian Fendt