Oscillations of rotating magnetised neutron stars with purely toroidal magnetic fields
arXiv:0912.3480 · doi:10.1111/j.1365-2966.2010.16435.x
Abstract
We investigate the oscillation spectrum of rotating Newtonian neutron stars endowed with purely toroidal magnetic fields, using a time evolution code to evolve linear perturbations in the Cowling approximation. The background star is generated by numerically solving the MHD equilibrium equations and may be nonspherical by virtue of both rotation and magnetic effects; hence our perturbations and background are fully consistent. Whilst the background field is purely toroidal, the perturbed field is mixed poloidal-toroidal. From Fourier analysis of the perturbations we are able to identify a number of magnetically-restored Alfvén (or -) modes. We show that in a rotating star pure inertial and -modes are replaced by hybrid magneto-inertial modes, which reduce to -modes in the nonrotating limit and inertial modes in the nonmagnetic limit. We show that the -mode instability is suppressed by magnetic fields in sufficiently slowly rotating stars. In addition, we determine magnetic frequency shifts in the -mode. We discuss the astrophysical relevance of our results, in particular for magnetar oscillations.
15 pages, 9 figures
References in corpus (11)
- Magnetic fields in axisymmetric neutron stars
- On the theory of magnetar QPOs
- Alfvén QPOs in Magnetars
- Neutron star oscillations and QPOs during magnetar flares
- Relativistic g-modes in rapidly rotating neutron stars
- Oscillations of rapidly rotating stratified neutron stars
- Alfvén Polar Oscillations of Relativistic Stars
- Axisymmetric oscillations of magnetic neutron stars
- Evolution of neutron stars with toroidal magnetic fields: Axisymmetric simulation in full general relativity
- Magnetars versus Radio Pulsars: MHD Stability in Newborn Highly Magnetized Neutron Stars
- Lagrangian perturbation theory for rotating magnetic stars
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