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We present time-dependent numerical hydrodynamic models of line-driven accretion disk winds in cataclysmic variable systems and calculate wind mass-loss rates and terminal velocities. The models are 2.5-dimensional, include an energy…

Astrophysics · Physics 2009-11-07 Nicolas A. Pereyra , Timothy R. Kallman

We constructed a multi-fluid two-dimensional hydrodynamic model with detailed radiative transfer to depict the escape of particles. We found that the tidal forces supply significant accelerations and result in anisotropic winds. An…

Earth and Planetary Astrophysics · Physics 2015-06-15 J. H. Guo

Astrophysical discs which are sufficiently massive and cool are linearly unstable to the formation of axisymmetric structures. In practice, linearly stable discs of surface density slightly below the threshold needed for this instability…

Earth and Planetary Astrophysics · Physics 2025-01-22 Joshua J. Brown , Gordon I. Ogilvie

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

Non-axisymmetric accretion discs can lead to flux variability. Here we provide an analytic framework for modeling non-axisymmetric structures like hotspots and spiral waves and their influence on observed timing measurements. The presently…

Astrophysics · Physics 2009-11-11 P. Varniere , E. Blackman

We explore effects of random non-axisymmetric perturbations of kinetic helicity (the $\alpha$ effect) and diffusive decay of bipolar magnetic regions on generation and evolution of large-scale non-axisymmetric magnetic fields on the Sun.…

Solar and Stellar Astrophysics · Physics 2018-11-28 V. V. Pipin , A. G. Kosovichev

Stationary magnetohydrodynamic (MHD) outflows from a rotating, conducting Keplerian accretion disk threaded by B-field are investigated numerically by time-dependent, axisymmetric (2.5D) simulations using a Godunov-type code. A large class…

Two-dimensional (axially symmetric) numerical hydrodynamical calculations of accretion flows which cannot cool through emission of radiation are presented. The calculations begin from an equilibrium configuration consisting of a thick torus…

Astrophysics · Physics 2009-10-31 James M. Stone , James E. Pringle , Mitchell C. Begelman

Recent work by Pringle and by Maloney, Begelman & Pringle has shown that geometrically thin, optically thick, accretion disks are unstable to warping driven by radiation torque from the central source. In this paper we generalize the study…

Astrophysics · Physics 2009-10-30 Philip R. Maloney , Mitchell C. Begelman , Michael A. Nowak

We investigate the launching of outflows from the disk-magnetosphere boundary of slowly and rapidly rotating magnetized stars using axisymmetric and exploratory 3D magnetohydrodynamic (MHD) simulations. We find long-lasting outflows in both…

Solar and Stellar Astrophysics · Physics 2015-05-13 M. M. Romanova , G. V. Ustyugova , A. V. Koldoba , R. V. E. Lovelace

We present an analytic, quasi-local model for accretion discs threaded by net, vertical magnetic flux. In a simple slab geometry and ignoring stochastic mean-field dynamo effects, we calculate the large-scale field resulting from the…

High Energy Astrophysical Phenomena · Physics 2024-10-18 Mitchell C. Begelman

Infrared interferometry of local AGN has revealed a warm (~300K-400K) polar dust structure that cannot be trivially explained by the putative dust torus of the unified model. This led to the development of the disk+wind scenario which…

Magnetized disk winds and wind-driven accretion are an essential and intensively studied dispersion mechanism of protoplanetary disks. However, the stability of these mechanisms has yet to be adequately examined. This paper employs…

Earth and Planetary Astrophysics · Physics 2024-07-04 Lile Wang , Sheng Xu , Zhenyu Wang , Min Fang , Jeremy Goodman

We perform numerical simulations of magneto-rotational instability in a local patch of accretion disk in which radiation pressure exceeds gas pressure. Such conditions may occur in the central regions of disks surrounding compact objects in…

Astrophysics · Physics 2007-05-23 N. J. Turner , J. M. Stone , T. Sano

AIMS. The amplitude and scaleheight of the Galactic gas disc density are not axisymmetric against expectations in a self-gravity axisymmetric disc. However, this lopsidedness can be explained in terms of intergalactic accretion flows, which…

Astrophysics · Physics 2009-11-13 M. Lopez-Corredoira , J. Betancort-Rijo

We review the main results from axisymmetric, time-dependent hydrodynamical simulations of radiation driven disk winds in AGN. We illustrate the capability of such simulations to provide useful insights into the three domains of…

Cosmology and Nongalactic Astrophysics · Physics 2012-01-18 Daniel Proga , Paola Rodríguez Hidalgo , Fred Hamann

We study the axisymmetric and non-axisymmetric, time-dependent hydrodynamics of gas that is under the influence of the gravity of a super massive black hole (SMBH) and the radiation force produced by a radiatively efficient flow accreting…

Astrophysics · Physics 2011-02-11 Ryuichi Kurosawa , Daniel Proga

Magnetic, radiation pressure, and thermal driving are the three mechanisms capable of launching accretion disk winds. In X-ray binaries, radiation pressure is often not significant, as in many systems the luminosity is too low for driving…

High Energy Astrophysical Phenomena · Physics 2018-09-18 Tim Waters , Daniel Proga

The evolution of protoplanetary discs and the related process of planet formation is regulated by angular momentum transport and mass-loss processes. Over the past decade, the paradigm of viscosity has been challenged and MHD disc winds…

Solar and Stellar Astrophysics · Physics 2021-12-08 Benoît Tabone , Giovanni P. Rosotti , Alexander J. Cridland , Philip J. Armitage , Giuseppe Lodato

We study the linear perturbations of collisionless near-Keplerian discs. Such systems are models for debris discs around stars and the stellar discs surrounding supermassive black holes at the centres of galaxies. Using a finite-element…

Earth and Planetary Astrophysics · Physics 2015-05-30 Mir Abbas Jalali , Scott Tremaine