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Related papers: Accretion disc backflow in resistive MHD simulatio…

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We present the results of a global, three-dimensional magnetohydrodynamics simulation of an accretion disk with a rotating, weakly magnetized central star. The disk is threaded by a weak, large-scale poloidal magnetic field, and the central…

Solar and Stellar Astrophysics · Physics 2019-02-07 Shinsuke Takasao , Kengo Tomida , Kazunari Iwasaki , Takeru K. Suzuki

Two-dimensional accretion flows near black holes have been investigated by time-dependent hydrodynamical calculations. We assume that the flow is axisymmetric and that radiative losses of internal energy are negligible, so that the disc is…

Astrophysics · Physics 2015-06-24 Igor V. Igumenshchev , Xingming Chen , Marek A. Abramowicz

We describe a three-dimensional, Godunov-type numerical magnetohydrodynamics (MHD) method designed for studying disk accretion to a rotating magnetized star in the general case where the star's rotation axis, its magnetic moment, and the…

Astrophysics · Physics 2009-11-07 A. V. Koldoba , M. M. Romanova , G. V. Ustyugova , R. V. E. Lovelace

In this paper, we develop the analysis of a two-dimensional magnetohydrodynamical configuration for an axially symmetric and rotating plasma (embedded in a dipole like magnetic field), modeling the structure of a thin accretion disk around…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Giovanni Montani , Riccardo Benini

(Abridged) Finite radius accretion disks are a strong candidate for launching astrophysical jets from their inner parts and disk-winds are considered as the basic component of such magnetically collimated outflows. The only available…

Understanding how accretion proceeds in proto-planetary discs and more generally their dynamics is a crucial issue for explaining the conditions in which planets form. The role that accretion of gas from the surrounding molecular cloud onto…

Astrophysics of Galaxies · Physics 2017-03-15 Patrick Hennebelle , Geoffroy Lesur , Sébastien Fromang

Observed accretion rates onto the Milky-Way and other local spirals fall short of that required to sustain star formation for cosmological timescales. A potential avenue for this unseen accretion is an inflow in the volume-filling hot phase…

We report on a new class of solutions of black hole accretion disks that we have found through three-dimensional, global, radiative magnetohydrodynamic simulations in general relativity. It combines features of the canonical thin, slim and…

We present the two-dimensional inflow-outflow solutions of radiation hydrodynamic (RHD) equations of supercritical accretion flows. Compared with prior studies, we include all components of the viscous stress tensor. We assume steady state…

High Energy Astrophysical Phenomena · Physics 2020-01-15 Fatemeh Zahra Zeraatgari , Amin Mosallanezhad , Ye-Fei Yuan , De-Fu Bu , Liquan Mei

We analyse the two-dimensional MHD configurations characterising the steady state of the accretion disk on a highly magnetised neutron star. The model we describe has a local character and represents the extension of the crystalline…

High Energy Astrophysical Phenomena · Physics 2014-11-20 Giovanni Montani , Riccardo Benini

We use local numerical simulations to investigate the strength and nature of magnetohydrodynamic (MHD) turbulence in the outer regions of protoplanetary disks, where ambipolar diffusion is the dominant non-ideal MHD effect. The simulations…

Solar and Stellar Astrophysics · Physics 2015-06-11 Jacob B. Simon , Xue-Ning Bai , James M. Stone , Philip J. Armitage , Kris Beckwith

We examine the morphology of magnetic structures in thin plasma accretion discs, generalizing a stationary ideal MHD model to the time-dependent visco-resistive case. Our analysis deals with small scale perturbations to a central…

High Energy Astrophysical Phenomena · Physics 2015-06-11 Giovanni Montani , Jacopo Petitta

In two previous publications$^{1,2}$, we have demonstrated that stationary rotation of magnetized plasma about a compact central object permits an enormous number of different MHD instabilities, with the well-known magneto-rotational…

Plasma Physics · Physics 2007-05-23 Hans Goedbloed , Rony Keppens

We compute the properties of a geometrically thin, steady accretion disk surrounding a central rotating, magnetized star. The magnetosphere is assumed to entrain the disk over a wide range of radii. The model is simplified in that we adopt…

Astrophysics · Physics 2012-08-13 W. Kluzniak , S. Rappaport

We formulate the problem of the late accretion phase of the evolution of an isothermal magnetic disk surrounding a forming star. The evolution is described by the six-fluid MHD equations, accounting for the presence of neutrals, atomic and…

Astrophysics · Physics 2009-11-10 Konstantinos Tassis , Telemachos Ch. Mouschovias

The aim of this paper is to study the vertical profile of small dust particles in protoplanetary discs in which angular momentum transport is due to MHD turbulence driven by the magnetorotational instability. We consider particle sizes that…

Earth and Planetary Astrophysics · Physics 2009-11-13 Sebastien Fromang , Richard P. Nelson

This paper examines the outflows associated with the interaction of a stellar magnetosphere with an accretion disk. In particular, we investigate the magnetospheric ejections (MEs) due to the expansion and reconnection of the field lines…

Solar and Stellar Astrophysics · Physics 2015-06-12 Claudio Zanni , Jonathan Ferreira

This work investigates Bondi accretion to a rotating magnetized star in the "propeller" regime using axisymmetric resistive, magnetohydrodynamic simulations. In this regime accreting matter tends to be expelled from the equatorial region of…

Astrophysics · Physics 2009-11-07 M. M. Romanova , O. D. Toropina , Yu. M. Toropin , R. V. E. Lovelace

Photon trapping and outflow are two key physics associated with the supercritical accretion flow. We investigate the conflict between these two processes based on two-dimensional radiation-hydrodynamic (RHD) simulation data and construct a…

High Energy Astrophysical Phenomena · Physics 2015-05-13 Shun Takeuchi , Shin Mineshige , Ken Ohsuga

The source of viscosity in astrophysical accretion flows is still a hotly debated issue. We investigate the contribution of convective turbulence to the total viscosity in a self-consistent approach, where the strength of convection is…

High Energy Astrophysical Phenomena · Physics 2015-05-13 Dominikus Heinzeller , Wolfgang J. Duschl , Shin Mineshige
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