2018/02/14 by Umin Lee
Earth and Planetary Sciences · Engineering · Physics and Astronomy · #Astrophysics #Classical mechanics #Computational physics #Geophysics and Sensor Technology #High-pressure geophysics and materials #Magnetic field #Magnetohydrodynamics #Mechanics #Neutron star #Nuclear physics #Physics #Plasma #Polytrope #Polytropic process #Pulsars and Gravitational Waves Research #Quantum mechanics #Rotational symmetry #Stellar magnetic field #Toroid #Toroidal and poloidal #astro-ph.HE
paper · pdf · doi:10.1093/mnras/sty406
17 pages, 10 figures, submitted to MNRAS
arxiv created 2018/02/14 · openalex publication_date 2018/02/15 · openalex created_date 2018/02/23 · arxiv updated 2018/03/14 · openalex updated_date 2026/08/05
We calculate axisymmetric magnetic modes of a neutron star possessing a mixed poloidal and toroidal magnetic field, where the toroidal field is assumed to be proportional to a dimensionless parameter ζ0. Here, we assume an isentropic structure for the neutron star and consider no effects of rotation. Ignoring the equilibrium deformation due to the magnetic field, we employ a polytrope of the index n = 1 as the background model for our modal analyses. For the mixed poloidal and toroidal magnetic field with |ζ 0\not=0|, axisymmetric spheroidal and toroidal modes are coupled. We compute axisymmetric spheroidal and toroidal magnetic modes as a function of the parameter ζ0 from 0 to ∼1 for the surface field strengths BS = 1014 G and 1015 G. We find that the frequency ω of the magnetic modes decreases with increasing ζ0. We also find that the frequency of the spheroidal magnetic modes is almost exactly proportional to BS for ζ0 ≲ 1 but that this proportionality holds only when ζ0 ≪ 1 for the toroidal magnetic modes. The wave patterns of the spheroidal magnetic modes and toroidal magnetic modes are not strongly affected by the coupling so long as ζ0 ≲ 1. We find no unstable modes having ω2 < 0.