2009/12/20 by S. K. Lander, D. I. Jones, Andrea Passamonti +1 · 2 citations
Earth and Planetary Sciences · Physics and Astronomy · #Astrophysics #Classical mechanics #Computational physics #Gamma-ray bursts and supernovae #Geophysics and Gravity Measurements #Inertial frame of reference #Instability #Magnetar #Magnetic field #Magnetohydrodynamics #Mechanics #Neutron star #Oscillation (cell signaling) #Physics #Plasma #Pulsars and Gravitational Waves Research #Quantum electrodynamics #Quantum mechanics #Rotation (mathematics) #Stars #Stellar rotation #Toroid #astro-ph.SR
paper · pdf · doi:10.1111/j.1365-2966.2010.16435.x
published as MNRAS 405, 318 (2010) · 15 pages, 9 figures
arxiv created 2009/12/20 · openalex publication_date 2010/03/01 · arxiv updated 2012/02/10 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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 magnetohydrodynamics equilibrium equations and may be non-spherical 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 a) modes. We show that in a rotating star pure inertial and a-modes are replaced by hybrid magneto-inertial modes, which reduce to a-modes in the non-rotating limit and inertial modes in the non-magnetic limit. We show that the r-mode instability is suppressed by magnetic fields in sufficiently slowly rotating stars. In addition, we determine magnetic frequency shifts in the f-mode. We discuss the astrophysical relevance of our results, in particular for magnetar oscillations.