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相关论文: MRI-driven $\alpha\Omega$ dynamo at high Pm number…

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Fluctuation dynamos provide a robust mechanism for amplifying weak seed magnetic fields in turbulent astrophysical plasmas. However, their behaviour in the highly compressible regimes characteristic of the interstellar medium remains…

星系天体物理 · 物理学 2026-02-18 Ameya Uday Nagdeo , Sharanya Sur , Bhargav Vaidya

The magnetorotational instability (MRI) has been suggested to have an important role on the dynamics of accretion disks. We investigate MRI as an alternative way for guiding the plasma from the disk to the funnel flow at the…

高能天体物理现象 · 物理学 2012-10-08 S. Dogan , E. R. Pekunlu

We present three-dimensional magnetohydrodynamic simulations of the nonlinear evolution of the magnetorotational instability (MRI) with a non-zero Ohmic resistivity. The properties of the saturated state depend on the initial magnetic field…

天体物理学 · 物理学 2009-10-31 Timothy P. Fleming , James M. Stone , John F. Hawley

The strength and structure of the large-scale magnetic field in protoplanetary discs are still unknown, although they could have important consequences for the dynamics and evolution of the disc. Using a mean-field approach in which we…

地球与行星天体物理 · 物理学 2015-06-19 Jerome Guilet , Gordon I. Ogilvie

Convection has been discussed in the field of accretion discs for several decades, both as a means of angular momentum transport and also because of its role in controlling discs' vertical structure via heat transport. If the gas is…

太阳与恒星天体物理 · 物理学 2021-04-21 Loren E. Held , Henrik N. Latter

The amplification of a magnetic field due to the Richtmyer-Meshkov instability (RMI) is investigated by two-dimensional MHD simulations. Single-mode analysis is adopted to reveal definite relation between the nonlinear evolution of RMI and…

高能天体物理现象 · 物理学 2015-06-11 Takayoshi Sano , Katsunobu Nishihara , Chihiro Matsuoka , Tsuyoshi Inoue

(Abridged) Based on the rapidly increasing all-sky data of Faraday rotation measures and polarised synchrotron radiation, the Milky Way's magnetic field is now modelled with an unprecedented level of detail and complexity. We aim to…

星系天体物理 · 物理学 2015-06-17 Oliver Gressel , Detlef Elstner , Udo Ziegler

Low-mass galaxies radio observations show in many cases surprisingly high levels of magnetic field. The mass and kinematics of such objects do not favour the development of effective large-scale dynamo action. We attempted to check if the…

星系天体物理 · 物理学 2018-03-14 Hubert Siejkowski , Marian Soida , Krzysztof T. Chyzy

The magnetorotational instability (MRI) plays a crucial role in regulating the accretion efficiency in astrophysical accretion disks. In low-luminosity disks around black holes, such as Sgr A* and M87, Coulomb collisions are infrequent,…

高能天体物理现象 · 物理学 2023-08-25 Astor Sandoval , Mario Riquelme , Anatoly Spitkovsky , Fabio Bacchini

Angular momentum in protostellar discs can be transported either radially, through turbulence induced by the magnetorotational instability (MRI), or vertically, through the torque exerted by a large-scale magnetic field. We present a model…

天体物理学 · 物理学 2009-11-13 Raquel Salmeron , Arieh Königl , Mark Wardle

In the recent years, MRI-driven turbulent transport has been found to depend in a significant way on fluid viscosity $\nu$ and resistivity $\eta$ through the magnetic Prandtl number $Pm=\nu/\eta$. In particular, the transport decreases with…

太阳与恒星天体物理 · 物理学 2015-05-18 P. -Y. Longaretti , G. Lesur

Strongly magnetized accretion discs around black holes have attractive features that may explain enigmatic aspects of X-ray binary behaviour. The structure and evolution of these discs are governed by a dynamo-like mechanism, which channels…

高能天体物理现象 · 物理学 2016-02-03 Greg Salvesen , Jacob B. Simon , Philip J. Armitage , Mitchell C. Begelman

Hot accretion flows contain collisionless plasmas that are believed to be capable of accelerating particles to very high energies, as a result of turbulence generated by the magnetorotational instability (MRI). We conduct unstratified…

高能天体物理现象 · 物理学 2021-07-14 Xiaochen Sun , Xue-Ning Bai

In this paper we show that the Universe is already strongly magnetized at very early epochs during cosmic evolution. Our calculations are based on the efficient amplification of weak magnetic seed fields, which are unavoidably present in…

宇宙学与河外天体物理 · 物理学 2014-05-09 Jacques M. Wagstaff , Robi Banerjee , Dominik Schleicher , Guenter Sigl

We investigate the build-up of the galactic dynamo and subsequently the origin of a magnetic driven outflow. We use a setup of an isolated disc galaxy with a realistic circum-galactic medium (CGM). We find good agreement of the galactic…

In the presence of strong density stratification, turbulence can lead to a large-scale instability of a horizontal magnetic field if its strength is in a suitable range (within a few percent of the turbulent equipartition value). This…

太阳与恒星天体物理 · 物理学 2014-04-28 Sarah Jabbari , Axel Brandenburg , Nathan Kleeorin , Dhrubaditya Mitra , Igor Rogachevskii

A rigorous theory for the generation of a large-scale magnetic field by random non-helically forced motions of a conducting fluid combined with a linear shear is presented in the analytically tractable limit of low Rm and weak shear. The…

天体物理学 · 物理学 2011-12-15 T. Heinemann , J. C. McWilliams , A. A. Schekochihin

We use three dimensional radiation magneto-hydrodynamic simulations to study the effects of magnetic fields on the energy transport and structure of radiation pressure dominated main sequence massive star envelopes at the region of the iron…

太阳与恒星天体物理 · 物理学 2017-07-19 Yan-Fei Jiang , Matteo Cantiello , Lars Bildsten , Eliot Quataert , Omer Blaes

We present the first kinematic study of an $\alpha\Omega$-dynamo in the General Relativistic Magneto-HydroDynamics (GRMHD) regime, applied to thick disks orbiting around Kerr black holes and using a fully covariant mean field dynamo closure…

高能天体物理现象 · 物理学 2015-06-18 M. Bugli , L. Del Zanna , N. Bucciantini

Large-scale coherent magnetic fields observed in the nearby galaxies are thought to originate by a mean-field dynamo. This is governed via the turbulent electromotive force (EMF, $\overline{\mathcal{E}} $) generated by the helical…

星系天体物理 · 物理学 2020-11-18 Abhijit B. Bendre , Detlef Elstner , Oliver Gressel