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Related papers: Backflow in simulated MHD accretion disks

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Recent observations uncover various phenomena around the protostar such as misalignment between the outflow and magnetic field, precession of the jet, and time variability of the ejected clumps, whose origins are under debate. We perform a…

Solar and Stellar Astrophysics · Physics 2019-03-20 Shingo Hirano , Masahiro N. Machida

The MHD flow driven by a travelling magnetic field (TMF) in an annular channel is investigated numerically. For sufficiently large magnetic Reynolds number Rm, or if a large enough pressure gradient is externally applied, the system…

Fluid Dynamics · Physics 2016-03-23 Christophe Gissinger , Paola Rodriguez-Imazio , Stephan Fauve

We present a global magnetohydrodynamic (MHD) three dimensional simulation of a nonradiative accretion flow originating in a pressure supported torus. The evolution is controlled by the magnetorotational instability which produces…

Astrophysics · Physics 2009-11-06 John F. Hawley , Steven A. Balbus , James M. Stone

The role of MHD turbulence in astrophysical environments is still highly debated. An important question that permeates this debate is the transport of magnetic flux. This is particularly important, for instance, in the context of star…

We have developed a modified form of the equations of smoothed particle magnetohydrodynamics which are stable in the presence of very steep density gradients. Using this formalism, we have performed simulations of the collapse of magnetised…

Solar and Stellar Astrophysics · Physics 2018-03-29 Benjamin T. Lewis , Matthew R. Bate , Daniel J. Price

Stars and gaseous planets are magnetised objects but the influence of magnetic fields on their tidal responses and dissipation rates has not been well explored. We present the first exploratory nonlinear magnetohydrodynamic (MHD)…

Solar and Stellar Astrophysics · Physics 2024-11-26 Aurélie Astoul , Adrian J. Barker

In recent years, it has been demonstrated that massive stars see their infant circumstellar medium shaped into a large, irradiated, gravitationally unstable accretion disc during their early formation phase. Such discs constitute the gas…

Solar and Stellar Astrophysics · Physics 2024-05-31 D. M. -A. Meyer , E. Vorobyov

Flow reversals are rarely observed in low-Prandtl-number liquid metal convection due to the fluid's exceptionally high thermal diffusivity. Here, we demonstrate that an external transverse magnetic field can induce such reversals in a…

Fluid Dynamics · Physics 2025-11-11 Yan-Wu Cao , Ming-Zhu Ai , Long Chen , Juan-Cheng Yang , Ming-Jiu Ni

We study the flow structure in 3D magnetohydrodynamic (MHD) simulations of accretion onto Sagittarius A* via the magnetized winds of the orbiting Wolf-Rayet stars. These simulations cover over 3 orders of magnitude in radius to reach…

High Energy Astrophysical Phenomena · Physics 2020-01-29 Sean M. Ressler , Eliot Quataert , James M. Stone

We study the dynamics of super-Eddington accretion flows by performing two-dimensional radiation-hydrodynamic simulations. Compared with previous works, in this paper we include the $T_{\theta\phi}$ component of the viscous stress and…

High Energy Astrophysical Phenomena · Physics 2015-06-16 Xiao-Hong Yang , Feng Yuan , Ken Ohsuga , De-Fu Bu

The appearance and time variability of accreting millisecond X-ray pulsars (hereafter AMXPs, e.g. Wijnands & van der Klis 1998) depends strongly on the accretion rate, the effective viscosity and the effective magnetic diffusivity of the…

Astrophysics · Physics 2009-11-13 Marina M. Romanova , Akshay K. Kulkarni , Min Long , Richard V. E. Lovelace

The transport of angular momentum by magnetic fields is a crucial physical process in formation and evolution of stars and disks. Because the ionization degree in star forming clouds is extremely low, non-ideal magnetohydrodynamic (MHD)…

Solar and Stellar Astrophysics · Physics 2015-06-23 Kengo Tomida , Satoshi Okuzumi , Masahiro N. Machida

The diffusion of astrophysical magnetic fields in conducting fluids in the presence of turbulence depends on whether magnetic fields can change their topology or reconnect in highly conducting media. Recent progress in understanding fast…

Astrophysics of Galaxies · Physics 2010-03-16 A. Lazarian , R. Santos-Lima , E. Gouveia Dal Pino

The formation of protostellar disks out of molecular cloud cores is still not fully understood. Under ideal MHD conditions, the removal of angular momentum from the disk progenitor by the typically embedded magnetic field may prevent the…

Astrophysics of Galaxies · Physics 2015-05-30 R. Santos-Lima , E. M. de Gouveia Dal Pino , A. Lazarian

We discuss three modes of oscillation of accretion disks around rotating magnetized neutron stars which may explain the separations of the kilo-Hertz quasi periodic oscillations (QPO) seen in low mass X-ray binaries. The existence of these…

High Energy Astrophysical Phenomena · Physics 2009-07-24 R. V. E. Lovelace , L. Turner , M. M. Romanova

We summarize recent 2D MHD simulations of line-driven stellar winds from rotating hot-stars with a dipole magnetic field aligned to the star's rotation axis. For moderate to strong fields, much wind outflow is initially along closed…

Astrophysics · Physics 2007-05-23 Stan Owocki , Asif ud-Doula

Grid-based magnetohydrodynamic (MHD) simulations have proven invaluable for the study of astrophysical accretion disks. However, the fact that angular momentum transport in disks is mediated by MHD turbulence (with structure down to very…

High Energy Astrophysical Phenomena · Physics 2015-05-28 Kareem A. Sorathia , Christopher S. Reynolds , James M. Stone , Kris Beckwith

Using numerical MHD simulations, we have studied the evolution of the magnetorotational instability in stratified accretion disks in which the ionization fraction (and therefore resistivity) varies substantially with height. This model is…

Astrophysics · Physics 2009-11-07 Timothy Fleming , James M. Stone

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 study super-Eddington accretion flows onto black holes using a global three dimensional radiation magneto-hydrodynamical simulation. We solve the time dependent radiative transfer equation for the specific intensities to accurately…

High Energy Astrophysical Phenomena · Physics 2014-11-14 Yan-Fei Jiang , James M. Stone , Shane W. Davis
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