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Axisymmetric magnetohydrodynamic (MHD) simulations have been applied to investigate the interrelation of a central stellar magnetosphere and stellar wind with a surrounding magnetized disk outflow and how the overall formation of a large…

Astrophysics · Physics 2011-02-11 Christian Fendt

Outflows play a pivotal role in star formation as one of its most visible markers and a means of transporting mass, momentum, and angular momentum from the infalling gas into the surrounding molecular cloud. Their wide reach (at least…

Solar and Stellar Astrophysics · Physics 2024-03-18 Shantanu Basu , Mahmoud Sharkawi , Masahiro N. Machida

In star formation, magnetic fields act as a cosmic angular momentum extractor that increases mass accretion rates onto protostars and in the process, creates spectacular outflows. However, recently it has been argued that this magnetic…

Solar and Stellar Astrophysics · Physics 2014-11-20 Dennis F. Duffin , Ralph E. Pudritz

The generation process of magnetic field around a proto-first-star is studied. Utilizing the recent numerical result of proto-first-star formation based upon the radiation hydrodynamics simulations, we assess the magnetic field strength…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Yuki Shiromoto , Hajime Susa , Takashi Hosokawa

Describing the large-scale field topology of protoplanetary disks faces significant difficulties and uncertainties. The transport of the large-scale field inside the disk plays an important role in understanding its evolution. We aim to…

Solar and Stellar Astrophysics · Physics 2025-11-26 D. Steiner , L. Gehrig , M. Güdel

Magnetic fields are observed beyond the peripheries of optically detected galactic discs, while numerical models of their origin and the typical magnitudes are still absent. Previously, studies of galactic dynamo have avoided considering…

Astrophysics of Galaxies · Physics 2014-09-05 E. Mikhailov , A. Kasparova , D. Moss , R. Beck , D. Sokoloff , A. Zasov

Outflows driven by large-scale magnetic fields likely play an important role in the evolution and dispersal of protoplanetary disks, and in setting the conditions for planet formation. We extend our 2-D axisymmetric non-ideal MHD model of…

Earth and Planetary Astrophysics · Physics 2020-07-01 Oliver Gressel , Jon P. Ramsey , Christian Brinch , Richard P. Nelson , Neal J. Turner , Simon Bruderer

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…

Astrophysics of Galaxies · Physics 2018-03-14 Hubert Siejkowski , Marian Soida , Krzysztof T. Chyzy

The magnetic fields of spiral galaxies are so strong that they cannot be primordial. Their typical values are over one billion times higher than any value predicted for the early Universe. Explaining this immense growth and incorporating it…

Astrophysics of Galaxies · Physics 2020-09-30 Evangelia Ntormousi , Konstantinos Tassis , Fabio Del Sordo , Francesca Fragkoudi , Rüdiger Pakmor

Large-scale magnetic fields in the nuclear regions of protogalaxies can promote the formation and early growth of supermassive black holes (SMBHs) by direct collapse and magnetically boosted accretion. Turbulence associated with…

High Energy Astrophysical Phenomena · Physics 2023-09-06 Mitchell C. Begelman , Joseph Silk

We present two-dimensional, cylindrically symmetric simulations of hydrodynamic and magnetohydrodynamic (MHD) wide-angle winds interacting with a collapsing environment. These simulations have direct relevance to young stellar objects…

Astrophysics · Physics 2009-11-07 T. A. Gardiner , A. Frank , L. Hartmann

We derive analytically the vorticity generated downstream of a two-dimensional rippled hydromagnetic shock neglecting fluid viscosity and resistivity. The growth of the turbulent component of the downstream magnetic field is driven by the…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Federico Fraschetti

Magnetic fields likely play a key role in the dynamics and evolution of protoplanetary discs. They have the potential to efficiently transport angular momentum by MHD turbulence or via the magnetocentrifugal acceleration of outflows from…

Astrophysics · Physics 2009-06-23 Mark Wardle

The driving mechanism of massive outflows observed in high-mass star-forming regions is investigated using three-dimensional magnetohydrodynamics (MHD) and protostellar evolution calculations. In our previous paper, we showed that the mass…

Solar and Stellar Astrophysics · Physics 2018-01-31 Yuko Matsushita , Yuya Sakurai , Takashi Hosokawa , Masahiro N. Machida

We investigate outflows driven by a giant protoplanet using three-dimensional MHD nested grid simulations. We consider a local region around the protoplanet in the protoplanetary disk, and calculate three models: (a) unmagnetized disk…

Astrophysics · Physics 2011-02-11 Masahiro N. Machida , Shu-ichiro Inutsuka , Tomoaki Matsumoto

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…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-09 Jacques M. Wagstaff , Robi Banerjee , Dominik Schleicher , Guenter Sigl

Magnetic fields play an important role in astrophysical accretion discs, and in the interstellar and intergalactic medium. They drive jets, suppress fragmentation in star-forming clouds and can have a significant impact on the accretion…

Plasma Physics · Physics 2016-12-30 Christoph Federrath

Observations in polarized emission reveal the existence of large-scale coherent magnetic fields in a wide range of spiral galaxies. Radio-polarization data show that these fields are strongly inclined towards the radial direction, with…

Astrophysics · Physics 2009-11-13 Oliver Gressel , Udo Ziegler , Detlef Elstner , Günther Rüdiger

Star formation is thought to be triggered by the gravitational collapse of the dense cores of molecular clouds. Angular momentum conservation during the collapse results in the progressive increase of the centrifugal force, which eventually…

Earth and Planetary Astrophysics · Physics 2009-03-11 Raquel Salmeron

Current models of magnetars require extremely strong magnetic fields to explain their observed quiescent and bursting emission, implying that the field strength within the star's outer crust is orders of magnitude larger than the dipole…

Solar and Stellar Astrophysics · Physics 2016-04-07 Konstantinos N. Gourgouliatos , Toby Wood , Rainer Hollerbach