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Related papers: MRI-driven $\alpha-\Omega$ dynamos in protoneutron…

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The existence of a tachocline in the Sun has been proven by helioseismology. It is unknown whether a similar shear layer, widely regarded as the seat of magnetic dynamo action, also exists in a protoneutron star. Sudden jumps in magnetic…

Solar and Stellar Astrophysics · Physics 2011-10-06 Alpha Mastrano , Andrew Melatos

Magnetars are neutron stars with superstrong magnetic fields which can exceed 1e15 G. Some magnetars (the so-called soft gamma-repeaters) demonstrate occasionally very powerful processes of energy release, which result in exceptionally…

High Energy Astrophysical Phenomena · Physics 2024-09-18 D. G. Yakovlev

Star-forming dwarf galaxies can be seen as the local proxies of the high-redshift building blocks of more massive galaxies according to the current paradigm of the hierarchical galaxy formation. They are low-mass objects, and therefore…

Astrophysics of Galaxies · Physics 2015-06-18 H. Siejkowski , K. Otmianowska-Mazur , M. Soida , D. J. Bomans , M. Hanasz

Magnetars are young and highly magnetized neutron stars which display a wide array of X-ray activity including short bursts, large outbursts, giant flares and quasi-periodic oscillations, often coupled with interesting timing behavior…

High Energy Astrophysical Phenomena · Physics 2017-08-30 Victoria M. Kaspi , Andrei Beloborodov

As another step towards understanding the long-term evolution of the magnetic field in neutron stars, we provide the first simulations of ambipolar diffusion in a spherical star. Restricting ourselves to axial symmetry, we consider a…

High Energy Astrophysical Phenomena · Physics 2017-07-17 F. Castillo , A. Reisenegger , J. A. Valdivia

Numerical simulations of the magnetorotational instability (MRI) with zero initial net flux in a non-stratified isothermal cubic domain are used to demonstrate the importance of magnetic boundary conditions.In fully periodic systems the…

High Energy Astrophysical Phenomena · Physics 2011-07-08 Petri J. Käpylä , Maarit J. Korpi

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 propeller regime of disk accretion to a rapidly rotating magnetized star is investigated here for the first time by axisymmetric 2.5D magnetohydrodynamic simulations. An expanded, closed magnetosphere forms in which the magnetic field…

We present numerical magnetohydrodynamic (MHD) simulations of the effect of stellar dipole magnetic fields on line-driven wind outflows from hot, luminous stars. Unlike previous fixed-field analyses, the simulations here take full account…

Astrophysics · Physics 2011-05-05 Asif ud-Doula , Stanley P. Owocki

We propose the mean field dynamo model for the generation of strongest magnetic fields, $B\sim 10^{15}\,{\rm G}$, in a neutron star (NS) accounting for the chiral magnetic effect (CME) driven by the shock in a supernova (SN) progenitor of…

High Energy Astrophysical Phenomena · Physics 2020-04-08 Maxim Dvornikov , V. B. Semikoz , D. D. Sokoloff

We investigate the roles of magnetic fields and ambipolar diffusion during prestellar core formation in turbulent giant molecular clouds (GMCs), using three-dimensional numerical simulations. Our simulations focus on the shocked layer…

Solar and Stellar Astrophysics · Physics 2015-06-19 Che-Yu Chen , Eve C. Ostriker

In this paper we reconsider the problem of magnetic field diffusion in neutron star cores. We model the star as consisting of a mixture of neutrons, protons and electrons, and allow for particle reactions and binary collisions between…

Solar and Stellar Astrophysics · Physics 2015-05-20 K. Glampedakis , D. I. Jones , L. Samuelsson

Neutron stars are among the most fascinating astrophysical sources, being characterized by strong gravity, densities about the nuclear one or even above, and huge magnetic fields. Their observational signatures can be extremely diverse…

High Energy Astrophysical Phenomena · Physics 2017-11-06 L. Del Zanna , A. G. Pili , B. Olmi , N. Bucciantini , E. Amato

The origin of the strong magnetic fields measured in magnetars is one of the main uncertainties in the neutron star field. On the other hand, the recent discovery of a large number of such strongly magnetized neutron stars, is calling for…

High Energy Astrophysical Phenomena · Physics 2015-06-22 J. Martin , N. Rea , D. F. Torres , A. Papitto

The interstellar medium (ISM) is permeated by magnetic fields that affect gas dynamics and star formation. These fields correlate with supernova (SN)-driven turbulence, but whether the scaling is universal across galaxy properties, ISM…

Astrophysics of Galaxies · Physics 2026-03-31 Davide Belfiori , Sergio Martin-Alvarez , Enrique Lopez-Rodriguez , Rosita Paladino

We consider generation and evolution of small-scale magnetic fields in neutron stars. These fields can be generated by small-scale turbulent dynamo action soon after the collapse when the proto-neutron star is subject to convective and…

Astrophysics · Physics 2009-11-10 V. Urpin , J. Gil

We report the finding of an azimuthal dynamo wave of a low-order (m=1) mode in direct numerical simulations (DNS) of turbulent convection in spherical shells. Such waves are predicted by mean field dynamo theory and have been obtained…

Solar and Stellar Astrophysics · Physics 2013-12-19 Elizabeth Cole , Petri J. Käpylä , Maarit J. Mantere , Axel Brandenburg

We investigate the possibility of the growth of magnetorotational instability (MRI) in disks around Class 0 protostars. We construct a disk model and calculate the chemical reactions of neutral and charged atoms, molecules and dust grains…

Solar and Stellar Astrophysics · Physics 2021-05-12 Yoshihiro Kawasaki , Shunta Koga , Masahiro N. Machida

We study local magnetohydrodynamical (MHD) instabilities of differential rotation in magnetised, stably-stratified regions of stars and planets using a Cartesian Boussinesq model. We consider arbitrary latitudes and general shears (with…

Solar and Stellar Astrophysics · Physics 2024-10-10 Robert W. Dymott , Adrian J. Barker , Chris A. Jones , Steven M. Tobias

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
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