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Supernovae are known to be the dominant energy source for driving turbulence in the interstellar medium. Yet, their effect on magnetic field amplification in spiral galaxies is still poorly understood. Analytical models based on the…

Astrophysics of Galaxies · Physics 2010-01-29 Oliver Gressel

Euler's equations of motion are derived exactly for a rigid, triaxial, internally frictionless neutron star spinning down electromagnetically in vacuo. It is shown that the star precesses, but not freely: its regular precession relative to…

Astrophysics · Physics 2009-10-31 A. Melatos

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…

Astrophysics of Galaxies · Physics 2020-11-18 Abhijit B. Bendre , Detlef Elstner , Oliver Gressel

Magnetorotational instability (MRI) in a convectively-stable layer around the neutrinosphere is simulated by a three-dimensional model of supernova core. To resolve MRI-unstable modes, a thin layer approximation considering only the radial…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Youhei Masada , Tomoya Takiwaki , Kei Kotake

Motivated by prior remote observations of a transition from striated solar coronal structures to more isotropic ``flocculated'' fluctuations, we propose that the dynamics of the inner solar wind just outside the Alfv\'en critical zone, and…

It has long been known that solar-type stars undergo significant spin-down, via magnetic braking, during their Main-Sequence lifetimes. However, magnetic braking only operates on the surface layers; it is not yet completely understood how…

Solar and Stellar Astrophysics · Physics 2015-06-18 Rosie Oglethorpe , Pascale Garaud

We present a detailed analysis of the properties of twisted, force-free magnetospheres of non-rotating neutron stars, which are of interest in the modelling of magnetar properties and evolution. In our models the magnetic field smoothly…

High Energy Astrophysical Phenomena · Physics 2018-10-11 Taner Akgün , Juan Antonio Miralles , José A. Pons , Pablo Cerdá-Durán

We consider stability of differentially rotating non-magnetic proto-neutron stars. When neutrino transport is efficient, the star can be subject to a diffusive instability that can occur even in the convectively stable region. The…

Astrophysics · Physics 2009-11-13 V. Urpin

The nonlinear mean-field dynamo due to a shear-current effect in a nonhelical homogeneous turbulence with a mean velocity shear is discussed. The transport of magnetic helicity as a dynamical nonlinearity is taken into account. The…

Astrophysics · Physics 2009-11-11 I. Rogachevskii , N. Kleeorin , E. Liverts

We have investigated the turbulent mean-field dynamo action in protoneutron stars that are subject to convective and neutron finger instabilities. While the first one develops mostly in the inner regions of the star, the second one is…

Astrophysics · Physics 2009-11-10 Alfio Bonanno , Luciano Rezzolla , Vadim Urpin

Crystallization of dense matter in neutron star crusts and white dwarf cores may be similar to epitaxial crystal growth in terrestrial laboratories. However in stellar crystals, the spacing between horizontal planes has to gradually…

Solar and Stellar Astrophysics · Physics 2024-03-19 D. A. Baiko

Solar wind is probably the best laboratory to study turbulence in astrophysical plasmas. In addition to the presence of magnetic field, the differences with neutral fluid isotropic turbulence are: weakness of collisional dissipation and…

Solar and Stellar Astrophysics · Physics 2015-06-16 Olga Alexandrova , Christopher H. K. Chen , Luca Sorriso-Valvo , Timothy S. Horbury , Stuart D. Bale

The merger of two neutron stars may give birth to a long-lived hypermassive neutron star. If it harbours a strong magnetic field of magnetar strength, its spin-down could explain several features of short gamma-ray burst afterglows. The…

High Energy Astrophysical Phenomena · Physics 2017-08-23 Jerome Guilet , Andreas Bauswein , Oliver Just , Hans-Thomas Janka

Stellar interiors are the seat of efficient transport of angular momentum all along their evolution. Understanding the dependence of the turbulent transport triggered by the shear instabilities due to the differential rotation in stellar…

Solar and Stellar Astrophysics · Physics 2021-02-10 Junho Park , Vincent Prat , Stéphane Mathis , Lisa Bugnet

Flux-dominated solar dynamo models, which have demonstrated to be quite successful in reproducing most of the observed features of the large scale solar magnetic cycle, generally produce an inappropriate latitudinal distribution of the…

Astrophysics · Physics 2009-11-11 G. A. Guerrero , E. M. de Gouveia Dal Pino

It has been suggested that under solar coronal conditions, drift waves may contribute to coronal heating. Specific properties of the drift waves to be expected in the solar corona have, however, not yet been determined using more advanced…

Solar and Stellar Astrophysics · Physics 2024-08-14 Michaela Brchnelova , MJ Pueschel , Stefaan Poedts

We consider the physics of free precession of a rotating neutron star with an oblique magnetic field. We show that if the magnetic stresses are large enough, then there is no possibility of steady rotation, and precession is inevitable.…

Astrophysics · Physics 2009-11-07 Ira Wasserman

Helicity and \alpha effect driven by the nonaxisymmetric Tayler instability of toroidal magnetic fields in stellar radiation zones are computed. In the linear approximation a purely toroidal field always excites pairs of modes with…

Solar and Stellar Astrophysics · Physics 2015-05-28 G. Ruediger , L. L. Kitchatinov , D. Elstner

The self-consistent approach to the magnetic field evolution in neutron star cores, developed recently, is generalised to the case of superfluid and superconducting neutron stars. Applying this approach to the cold matter of neutron star…

High Energy Astrophysical Phenomena · Physics 2020-10-21 Mikhail E. Gusakov , Elena M. Kantor , Dmitry D. Ofengeim

We compare the current effects of rotation in stellar evolution to those of the magnetic field created by the Tayler instability. In stellar regions, where magnetic field can be generated by the dynamo due to differential rotation (Spruit…

Astrophysics · Physics 2009-11-10 Andre Maeder , Georges Meynet