English
Related papers

Related papers: Magnetic field evolution in high and low $\beta$ d…

200 papers

We use two-dimensional particle-in-cell simulations to investigate the generation and evolution of the magnetic field associated with the propagation of a jet for various initial conditions. We demonstrate that, in general, the magnetic…

High Energy Astrophysical Phenomena · Physics 2024-02-29 Amin Esmaeili , Yutaka Fujita

In weakly collisional extragalactic plasmas such as the intracluster medium, viscous stress and the rate of change of the magnetic-field strength are proportional to the local pressure anisotropy, so subject to constraints imposed by the…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-26 Federico Mogavero , Alexander A. Schekochihin

We perform local, vertically stratified shearing-box MHD simulations of protoplanetary disks (PPDs) at a fiducial radius of 1 AU that take into account the effects of both Ohmic resistivity and ambipolar diffusion (AD). The magnetic…

Earth and Planetary Astrophysics · Physics 2015-06-12 Xue-Ning Bai , James M. Stone

We perform direct numerical simulations of forced and freely decaying 3D magnetohydrodynamic turbulence in order to model magnetic field evolution during cosmological phase transitions in the early Universe. Our approach assumes the…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-30 Tina Kahniashvili , Axel Brandenburg , Alexander G. Tevzadze , Bharat Ratra

We study the evolution of a magnetic arcade that is anchored to an accretion disk and is sheared by the differential rotation of a Keplerian disk. By including an extremely low external plasma pressure at large distances, we obtain a…

Astrophysics · Physics 2009-11-06 H. Li , R. V. E. Lovelace , J. M. Finn , S. A. Colgate

Presence of a hot corona above the accretion disc can have important consequences for the evolution of magnetic fields and the Shakura-Sunyaev (SS) viscosity parameter $\alpha$ in such a strongly coupled system. In this work, we have…

High Energy Astrophysical Phenomena · Physics 2024-10-22 Nishant K. Singh , Arunima Ajay , S R Rajesh

We consider the hypothesis that galactic magnetic fields are primordial. We also discuss the various objections to this hypothesis. We assume that there was a magnetic field present in the galactic plasma before the galaxy formed. After the…

Astrophysics · Physics 2016-08-30 Armando M. Howard , Russell M. Kulsrud

We present 3D MHD simulations of purely toroidal and mixed poloidal-toroidal magnetic field configurations to study the behavior of the Tayler instability. For the first time the simultaneous action of rotation and magnetic diffusion are…

Solar and Stellar Astrophysics · Physics 2015-05-27 Juan C. Ibañez-Mejia , Jonathan Braithwaite

Giant protoplanets evacuate a gap in their host protoplanetary disc, which gas must cross before it can be accreted. A magnetic field is likely carried into the gap, potentially influencing the flow. Gap crossing has been simulated with…

Earth and Planetary Astrophysics · Physics 2015-08-06 Sarah L. Keith , Mark Wardle

We study the time evolution of a large-scale magnetic flux threading an accretion disk. Induction equation of the mean poloidal field is solved under the standard viscous disk model. Magnetic flux evolution is controlled by the two…

Earth and Planetary Astrophysics · Physics 2015-06-17 Taku Takeuchi , Satoshi Okuzumi

We conduct simulations of the inner regions of protoplanetary disks (PPDs) to investigate the effects of protostellar magnetic fields on their long-term evolution. We use an inner boundary model that incorporates the influence of a stellar…

Solar and Stellar Astrophysics · Physics 2021-12-01 D. Steiner , L. Gehrig , B. W. Ratschiner , F. Ragossnig , E. I. Vorobyov , M. Güdel , E. A. Dorfi

We present numerical simulations of driven magnetohydrodynamic (MHD) turbulence with weak/moderate imposed magnetic fields. The main goal is to clarify dynamics of magnetic field growth. We also investigate the effects of the imposed…

Astrophysics · Physics 2011-02-11 J. Cho , E. Vishniac , A. Beresnyak , A. Lazarian , D. Ryu

We present a set of three-dimensional, global, general relativistic radiation magnetohydrodynamic simulations of thin, radiation-pressure-dominated accretion disks surrounding a non-rotating, stellar-mass black hole. The simulations are…

High Energy Astrophysical Phenomena · Physics 2022-11-09 Bhupendra Mishra , P. Chris Fragile , Jessica Anderson , Aidan Blankenship , Hui Li , Krzysztof Nalewajko

In the early stages of a protoplanetary disk, when its mass is a significant fraction of its star's, turbulence generated by gravitational instability (GI) should feature significantly in the disk's evolution. At the same time, the disk may…

Earth and Planetary Astrophysics · Physics 2020-03-25 Hongping Deng , Lucio Mayer , Henrik Latter

A magnetic disc wind is an important mechanism that may be responsible for driving accretion and structure formation in protoplanetary discs. Recent numerical simulations have shown that these winds can take either the traditional…

Earth and Planetary Astrophysics · Physics 2020-08-19 Philip Kwong Ching Leung , Gordon I. Ogilvie

We have studied numerically the evolution of magnetic fields in barotropic neutron stars, by performing nonlinear magnetohydrodynamical simulations with the code PLUTO. For both initially predominantly poloidal and toroidal fields, with…

High Energy Astrophysical Phenomena · Physics 2020-09-22 Ankan Sur , Brynmor Haskell , Emily Kuhn

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 perform 3D radiation-magnetohydrodynamic simulations of the evolution of the fallback debris after a tidal disruption event. We focus on studying the effects of magnetic fields on the formation and early evolution of the accretion flow.…

High Energy Astrophysical Phenomena · Physics 2025-10-28 Maria Renee Meza , Xiaoshan Huang , Shane W. Davis , Yan-Fei Jiang

Magnetic effects have long been considered a possible factor in stabilizing the outer regions of active galactic nuclei (AGN) accretion disks against gravitational instability (GI). However, the computational demands of testing this…

High Energy Astrophysical Phenomena · Physics 2025-08-26 Hannalore J. Gerling-Dunsmore , Mitchell C. Begelman , Jacob B. Simon , Philip J. Armitage

We consider formation of accretion disks from a realistically turbulent molecular gas using 3D MHD simulations. In particular, we analyze the effect of the fast turbulent reconnection described by the Lazarian & Vishniac (1999) model for…

Solar and Stellar Astrophysics · Physics 2016-03-16 Diego F. González-Casanova , Reinaldo Santos-Lima , Alexander Lazarian