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Related papers: Secular evolution of MHD wind-driven discs: analyt…

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Rings and gaps are being observed in an increasing number of disks around young stellar objects. We illustrate the formation of such radial structures through idealized, 2D (axisymmetric) resistive MHD simulations of coupled disk-wind…

Solar and Stellar Astrophysics · Physics 2017-03-31 Scott S. Suriano , Zhi-Yun Li , Ruben Krasnopolsky , Hsien Shang

Conversion of gravitational energy into radiation in accretion discs and the origin of large scale magnetic fields in astrophysical rotators have often been distinct topics of research. In semi-analytic work on both problems it has been…

High Energy Astrophysical Phenomena · Physics 2015-06-04 Eric G. Blackman

The prevalence and consequences of convection perpendicular to the plane of accretion discs have been discussed for several decades. Recent simulations combining convection and the magnetorotational instability have given fresh impetus to…

Solar and Stellar Astrophysics · Physics 2018-08-08 Loren E. Held , Henrik N. Latter

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

Astrophysical accretion is arguably the most prevalent physical process in the Universe; it occurs during the birth and death of individual stars and plays a pivotal role in the evolution of entire galaxies. Accretion onto a black hole, in…

High Energy Astrophysical Phenomena · Physics 2009-12-09 Peter B. Dobbie , Zdenka Kuncic , Geoffrey V. Bicknell , Raquel Salmeron

Recent multi-band variability studies have revealed that active galactic nucleus (AGN) accretion disc sizes are generally larger than the predictions of the classical thin disc by a factor of $2\sim 3$. This hints at some missing key…

Astrophysics of Galaxies · Physics 2018-10-26 Mouyuan Sun , Yongquan Xue , Jonathan R. Trump , Wei-Min Gu

Observations indicate that wind can be generated in hot accretion flow. By performing numerical simulations, Yuan et al. studied the detailed properties of wind generated from weakly magnetized accretion flow. However, properties of wind…

High Energy Astrophysical Phenomena · Physics 2018-07-18 De-Fu Bu , Amin Mosallanezhad

The interaction between a protostellar magnetosphere and a surrounding dynamo-active accretion disc is investigated using an axisymmetric mean-field model. In all models investigated, the dynamo-generated magnetic field in the disc arranges…

Astrophysics · Physics 2009-11-10 Brigitta von Rekowski , Axel Brandenburg

(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

Protoplanetary disks are believed to accrete onto their central T Tauri star because of magnetic stresses. Recently published shearing box simulations indicate that Ohmic resistivity, ambipolar diffusion and the Hall effect all play…

Earth and Planetary Astrophysics · Physics 2015-06-23 Oliver Gressel , Neal J. Turner , Richard P. Nelson , Colin P. McNally

We aim to examine the detailed disc structure that arises in a misaligned binary system as a function of the disc aspect ratio h, viscosity parameter alpha, disc outer radius R, and binary inclination angle gamma_F. We also aim to examine…

Earth and Planetary Astrophysics · Physics 2015-05-14 Moritz Fragner , Richard Nelson

Spiral density waves are known to exist in many astrophysical disks, potentially affecting disk structure and evolution. We conduct a numerical study of the effects produced by a density wave, evolving into a shock, on the characteristics…

Earth and Planetary Astrophysics · Physics 2018-02-28 Lev Arzamasskiy , Roman R. Rafikov

We examine the migration of luminous low-mass cores in laminar protoplanetary discs where accretion occurs mainly because of disc winds and where the planet luminosity is generated by pebble accretion. Using 2D hydrodynamical simulations,…

Earth and Planetary Astrophysics · Physics 2022-10-26 Arnaud Pierens

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

We perform axisymmetric, two-dimensional magnetohydrodynamic (MHD) simulations to investigate accretion flows around spinning AGN. To mimic the space-time geometry of spinning black holes, we consider effective Kerr potential, and the mass…

High Energy Astrophysical Phenomena · Physics 2023-10-25 Ramiz Aktar , Kuo-Chuan Pan , Toru Okuda

X-ray observations of the tidal disruption event (TDE) candidate AT 2019avd show drastic variabilities in flux and spectral shape over hundreds of days, providing clues on the accretion disc-corona evolution. We utilize a disc-corona model,…

High Energy Astrophysical Phenomena · Physics 2026-03-27 Haichao Xu , Xinwu Cao , Yanan Wang , Andrzej A. Zdziarski

Cold steady-state disk wind theory from near Keplerian accretion disks requires a large scale magnetic field at near equipartition strength. However the minimum magnetization has never been tested. We investigate the time evolution of an…

Solar and Stellar Astrophysics · Physics 2015-03-13 Gareth C. Murphy , Jonathan Ferreira , Claudio Zanni

We characterize magnetically driven accretion at radii between 1 au and 100 au in protoplanetary discs, using a series of local non-ideal magnetohydrodynamic (MHD) simulations. The simulations assume a Minimum Mass Solar Nebula (MMSN) disc…

Solar and Stellar Astrophysics · Physics 2015-10-07 Jacob B. Simon , Geoffroy Lesur , Matthew W. Kunz , Philip J. Armitage

The growth and saturation of magnetic field in conducting turbulent media with large magnetic Prandtl numbers are investigated. This regime is very common in low-density hot astrophysical plasmas. During the early (kinematic) stage, weak…

Astrophysics · Physics 2009-11-07 A. A. Schekochihin , S. C. Cowley , G. W. Hammett , J. L. Maron , J. C. McWilliams

Many analyses have concluded that the accretion disc sizes measured from the microlensing variability of quasars are larger than the expectations from the standard thin disc theory by a factor of $\sim4$. We propose a simply model by…

High Energy Astrophysical Phenomena · Physics 2018-12-05 Ya-Ping Li , Feng Yuan , Xinyu Dai