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We conduct a series of magnetohydrodynamical (MHD) simulations of magnetized interstellar medium (ISM) disturbed by exploding stars. Each star deposits a randomly oriented, dipolar magnetic field into ISM. The simulations are performed in a…

Astrophysics · Physics 2011-11-10 K. Kowalik , M. Hanasz

In protoplanetary disks around young stars, magnetic fields play an important role for disk evolution and planet formation. Polarized thermal emission from magnetically aligned grains is one of the reliable methods to trace magnetic fields.…

Earth and Planetary Astrophysics · Physics 2025-02-11 Satoshi Ohashi , Takayuki Muto , Yusuke Tsukamoto , Akimasa Kataoka , Takashi Tsukagoshi , Munetake Momose , Misato Fukagawa , Nami Sakai

We apply a Fourier spectral numerical method to 3D incompressible MHD turbulence with a magnetic Prandtl number $Pr \geq 1$. We examine the processes by which an initially weak, large-scale seed magnetic field and an initially weak,…

Astrophysics · Physics 2009-10-31 Hongsong Chou

Protoplanetary disks are likely to be threaded by a weak net flux of vertical magnetic field that is a remnant of the much larger fluxes present in molecular cloud cores. If this flux is approximately conserved its dynamical importance will…

Earth and Planetary Astrophysics · Physics 2015-06-17 Philip J. Armitage , Jacob B. Simon , Rebecca G. Martin

Magnetic fields play a crucial role at all stages of the formation of low mass stars and planetary systems. In the final stages, in particular, they control the kinematics of in-falling gas from circumstellar discs, and the launching and…

Solar and Stellar Astrophysics · Physics 2015-05-19 S. G. Gregory , M. Jardine , C. G. Gray , J. -F. Donati

This talk summarizes results from recent MHD simulations of the role of a dipole magnetic field in inducing large-scale structure in the line-driven stellar winds of hot, luminous stars. Unlike previous fixed-field analyses, the MHD…

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

The origin of interstellar and intergalactic magnetic fields remains largely unknown. One possibility is that they are related to the primordial magnetic fields (PMFs) produced by, for instance, the phase transitions of the early Universe.…

High Energy Astrophysical Phenomena · Physics 2024-03-05 Yao-Yu Li , Chi Zhang , Ziwei Wang , Ming-Yang Cui , Yue-Lin Sming Tsai , Qiang Yuan , Yi-Zhong Fan

We study the two-dimensional, time-dependent MHD of radiation-driven winds from luminous accretion disks initially threaded by a purely axial magnetic field. The radiation force is mediated primarily by spectral lines. We use ideal MHD to…

Astrophysics · Physics 2009-11-07 D. Proga

Large scale strong magnetic fields in galaxies are generally thought to have been generated by a mean field dynamo. In order to have generated the fields observed, the dynamo would have had to have operated for a sufficiently long period of…

Astrophysics · Physics 2007-05-23 A. Kandus , R. Opher , S. R. M. Barros

Large-scale vertical magnetic fields are believed to play a key role in the evolution of protoplanetary discs. Associated with non-ideal effects, such as ambipolar diffusion, they are known to launch a wind that could drive accretion in the…

Earth and Planetary Astrophysics · Physics 2020-07-22 A. Riols , G. Lesur , F. Menard

We review the current theoretical models of the inward advection of the large scale external magnetic fields in accretion discs. The most plausible theories for launching astrophysical jets rely on strong magnetic fields at the inner parts…

High Energy Astrophysical Phenomena · Physics 2019-04-24 Amir Jafari

We have developed a hybrid model of the solar dynamo on the lines of the Babcock-Leighton idea that the poloidal field is generated at the surface of the Sun from the decay of active regions. In this model magnetic buoyancy is handled with…

Astrophysics · Physics 2007-05-23 Dibyendu Nandy

The amplification of primordial magnetic fields via a small-scale turbulent dynamo during structure formation might be able to explain the observed magnetic fields in galaxy clusters. The magnetisation of more tenuous large-scale structures…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 F. Vazza , M. Brüggen , C. Gheller , P. Wang

We investigate how misalignment between the core angular momentum and the large-scale magnetic field affects protostellar outflows, and whether a single protostellar system can drive multiple outflow components. We perform three-dimensional…

Solar and Stellar Astrophysics · Physics 2026-04-24 Shingo Hirano , Yuri Aikawa , Masahiro N. Machida

In the present-day universe, magnetic fields play such essential roles in star formation as angular momentum transport and outflow driving, which control circumstellar disc formation/fragmentation and also the star formation efficiency.…

Astrophysics of Galaxies · Physics 2022-12-28 Kenji Eric Sadanari , Kazuyuki Omukai , Kazuyuki Sugimura , Tomoaki Matsumoto , Kengo Tomida

An axisymmetric model of a cool, dynamo-active accretion disc is applied to protostellar discs. Thermally and magnetically driven outflows develop that are not collimated within 0.1 AU. In the presence of a central magnetic field from the…

Astrophysics · Physics 2009-11-10 Brigitta von Rekowski , Axel Brandenburg , Wolfgang Dobler , Anvar Shukurov

We review the literature concerning how the cosmic magnetic fields pervading nearly all galaxies actually got started. some observational evidence involves the chemical abundance of the light elements Be and B, while another one is based on…

Astrophysics · Physics 2009-11-13 Russell M. Kulsrud , Ellen G. Zweibel

Initial results from the Madison Dynamo Experiment provide details of the inductive response of a turbulent flow of liquid sodium to an applied magnetic field. The magnetic field structure is reconstructed from both internal and external…

Plasma Physics · Physics 2007-05-23 M. D. Nornberg , E. J. Spence , R. D. Kendrick , C. M. Jacobson , C. B. Forest

Radio continuum observations allow to reveal the magnetic field structure in the disk and halo of nearby spiral galaxies, their magnetic field strength and vertical scale heights. The spiral galaxies studied so far show a similar magnetic…

Astrophysics of Galaxies · Physics 2014-01-08 Marita Krause

Basically the only existing theories for the creation of a magnetic field B in the Universe are the creation of a seed field of order 10^{-20} G in spiral galaxy which is subsequently supposedly amplified up to the observed 10^{-6} -…

Astrophysics · Physics 2009-10-30 R. Opher , U. F. Wichoski