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We investigate the instability of purely poloidal magnetic fields in nonrotating neutron stars by means of three-dimensional general-relativistic magnetohydrodynamics simulations, extending the work presented in Ciolfi et al. (2011). Our…

Solar and Stellar Astrophysics · Physics 2015-06-05 Riccardo Ciolfi , Luciano Rezzolla

Dynamical instabilities in protoneutron stars may produce gravitational waves whose observation could shed light on the physics of core-collapse supernovae. When born with sufficient differential rotation, these stars are susceptible to a…

Magnetic fields have been observed in massive Ap/Bp stars and presumably are also present in the radiative zone of solar-like stars. Yet, to date there is no clear understanding of the dynamics of the magnetic field in stably stratified…

Solar and Stellar Astrophysics · Physics 2023-03-27 G. Monteiro , G. Guerrero , F. Del Sordo , A. Bonanno , P. K. Smolarkiewicz

In the present study, we addressed the question of how the growth rate of the magnetorotational instability is modified when the radial component of the stellar dipole magnetic field is taken into account in addition to the vertical…

Solar and Stellar Astrophysics · Physics 2020-02-07 Ebru Devlen , Ayse Ulubay , E. Rennan Pekünlü

Differential rotation in stars generates toroidal magnetic fields whenever an initial seed poloidal field is present. The resulting magnetic stresses, along with viscosity, drive the star toward uniform rotation. This magnetic braking has…

Astrophysics · Physics 2009-11-10 James N. Cook , Stuart L. Shapiro , Branson C. Stephens

Using nonlinear, fully relativistic, simulations we investigate the dynamics and gravitational-wave signature associated with instabilities in neutron star postmerger remnants. For simplified models of the remnant we establish the presence…

High Energy Astrophysical Phenomena · Physics 2020-09-02 Xiaoyi Xie , Ian Hawke , Andrea Passamonti , Nils Andersson

We study the radial and vertical stability of dust grains launched with all charge-to-mass ratios at arbitrary distances from rotating planets with complex magnetic fields. We show that the aligned dipole magnetic field model analyzed by…

Earth and Planetary Astrophysics · Physics 2012-06-06 Daniel Jontof-Hutter , Douglas P. Hamilton

During the last decade it has become evident that the magnetorotational instability is at the heart of the enhanced angular momentum transport in weakly magnetized accretion disks around neutron stars and black holes. In this paper, we…

Astrophysics · Physics 2009-11-10 Martin E. Pessah , Dimitrios Psaltis

The stability of large-scale magnetic fields in rotating stars is explored, using 3D numerical hydrodynamics to follow the evolution of an initial poloidal field. It is found that the field is subject to an instability, located initially on…

Astrophysics · Physics 2009-11-13 J. Braithwaite

A one-armed spiral instability has been found to develop in differentially rotating stellar models that have a relatively stiff, $n=1$ polytropic equation of state and a wide range of rotational energies. This suggests that such…

Astrophysics · Physics 2008-11-26 Shangli Ou , Joel E. Tohline

At second order in perturbation theory, the unstable r-mode of a rotating star includes growing differential rotation whose form and growth rate are determined by gravitational-radiation reaction. With no magnetic field, the angular…

High Energy Astrophysical Phenomena · Physics 2018-03-05 John L. Friedman , Lee Lindblom , Luciano Rezzolla , Andrey I. Chugunov

For a long time, gravitational instability in the disk of planetesimals has been suspected to be the main engine responsible for the beginning of dust growth, its advantage being that it provides for rapid growth. Its real importance in…

Astrophysics · Physics 2009-11-10 P. Tanga , S. J. Weidenschilling , P. Michel , D. C. Richardson

The evolution of a star is influenced by its internal rotation dynamics through transport and mixing mechanisms, which are poorly understood. Magnetic fields can play a role in transporting angular momentum and chemical elements, but the…

Solar and Stellar Astrophysics · Physics 2023-01-23 Ludovic Petitdemange , Florence Marcotte , Christophe Gissinger

We investigate whether angular momentum transport due to unstable pulsation modes can play a significant role in the rotational evolution of massive stars. We find that these modes can redistribute appreciable angular momentum, and moreover…

Astrophysics · Physics 2009-11-13 Rich Townsend , Jim MacDonald

The properties of the extremely strong magnetic fields of neutron stars affect in a unique way their evolution and the associated phenomenology. Due to the lack of constraints from direct observations, our understanding of the magnetic…

High Energy Astrophysical Phenomena · Physics 2015-06-22 Riccardo Ciolfi

We study static distributions of ferrofluid submitted to non-uniform magnetic fields. We show how the normal-field instability is modified in the presence of a weak magnetic field gradient. Then we consider a ferrofluid droplet and show how…

Fluid Dynamics · Physics 2018-03-14 Thibault Vieu , Clément Walter

We study the time evolution of non-axisymmetric linear perturbations of a rotating magnetised neutron star, whose magnetic field is multipolar and purely poloidal. The background stellar configurations are generated self-consistently,…

Solar and Stellar Astrophysics · Physics 2015-05-20 S. K. Lander , D. I. Jones

Magnetohydrodynamic (MHD) instabilities can play an important role in the structure and dynamics of the pulsar magnetosphere. We consider the instabilitycaused by differential rotation that is suggested by many theoretical models. Stability…

High Energy Astrophysical Phenomena · Physics 2015-06-04 V. Urpin

Observations of protostellar disks indicate the presence of the magnetic field of thermal (or superthermal) strength. In such a strong magnetic field, many MHD instabilities responsible for turbulent transport of the angular momentum are…

Astrophysics · Physics 2009-11-13 Alfio Bonanno , Vadim Urpin

The Tayler instability (TI) of toroidal magnetic fields is a candidate mechanism for driving turbulence, angular momentum (AM) transport, and dynamo action in stellar radiative zones. Recently \cite{Skoutnev_2024} revisited the linear…

Solar and Stellar Astrophysics · Physics 2025-06-24 Valentin A. Skoutnev , Andrei M. Beloborodov