On non-axisymmetric magnetic equilibria in stars

Abstract

In previous work stable approximately axisymmetric equilibrium configurations for magnetic stars were found by numerical simulation. Here I investigate the conditions under which more complex, non-axisymmetric configurations can form. I present numerical simulations of the formation of stable equilibria from turbulent initial conditions and demonstrate the existence of non-axisymmetric equilibria consisting of twisted flux tubes lying horizontally below the surface of the star, meandering around the star in random patterns. Whether such a non-axisymmetric equilibrium or a simple axisymmetric equilibrium forms depends on the radial profile of the strength of the initial magnetic field. The results could explain observations of non-dipolar fields on stars such as the B0.2 main-sequence star tau-Sco or the pulsar 1E 1207.4-5209. The secular evolution of these equilibria due to Ohmic and buoyancy processes is also examined.

13 pages, 12 figures. Accepted by MNRAS

References in corpus (6)

• Physics of Strongly Magnetized Neutron Stars
• The surprising magnetic topology of tauSco: fossil remnant or dynamo output?
• The stability of poloidal magnetic fields in rotating stars
• Protoneutron star dynamos: pulsars, magnetars, and radio-silent X-ray emitting neutron stars
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• Origin and evolution of magnetic fields in PMS stars : influence of rotation and structural changes
• Magnetic field topology and chemical abundance distributions of the young, rapidly rotating chemically peculiar star HR5624
• Magnetar activity mediated by plastic deformations of neutron star crust
• Three-dimensional magnetic and abundance mapping of the cool Ap star HD 24712 II. Two-dimensional Magnetic Doppler Imaging in all four Stokes parameters
• Magnetic characterization of the SPB/$\beta$ Cep hybrid pulsator HD 43317
• Stability of toroidal magnetic fields in stellar interiors
• The nature of the light variability of magnetic Of?p star HD 191612
• Appearance of the prolate and the toroidal magnetic field dominated stars - Analytic approach