{
  "id": "1802.04957",
  "version": "v1",
  "published": "2018-02-14T05:02:48.000Z",
  "updated": "2018-02-14T05:02:48.000Z",
  "title": "Axisymmetric magnetic modes of neutron stars having mixed poloidal and toroidal magnetic fields",
  "authors": [
    "Umin Lee"
  ],
  "comment": "17 pages, 10 figures, submitted to MNRAS",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "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 $\\zeta_0$. 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 $\\zeta_0\\not=0$, axisymmetric spheroidal and toroidal modes are coupled. We compute axisymmetric spheroidal and toroidal magnetic modes as a function of the parameter $\\zeta_0$ from $0$ to $\\sim 1$ for the surface field strengths $B_S=10^{14}$G and $10^{15}$G. We find that the frequency $\\omega$ of the magnetic modes decreases with increasing $\\zeta_0$. We also find that the frequency of the spheroidal magnetic modes is almost exactly proportional to $B_S$ for $\\zeta_0\\lesssim 1$ but that this proportionality holds only when $\\zeta_0\\ll 1$ 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 $\\zeta_0\\lesssim 1$. We find no unstable modes having $\\omega^2<0$.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2018-02-14T05:02:48.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "toroidal magnetic field",
      "axisymmetric magnetic modes",
      "neutron star",
      "mixed poloidal",
      "toroidal magnetic modes"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 17,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}