Evolutionary deformation toward the elastic limit by a magnetic field confined in the neutron--star crust

Abstract

Occasional energetic outbursts and anomalous X-ray luminosities are expected to be powered by the strong magnetic field in a neutron star. For a very strong magnetic field, elastic deformation becomes excessively large such that it leads to crustal failure. We studied the evolutionary process driven by the Hall drift for a magnetic field confined inside the crust. Assuming that the elastic force acts against the Lorentz force, we examined the duration of the elastic regime and maximum elastic energy stored before the critical state. The breakup time was longer than that required for extending the field to the exterior, because the tangential components of the Lorentz force vanished in the fragile surface region. The conversion of large magnetic energy, confined to the interior, into Joule heat is considered to explain the power for central compact objects. This process can function without reaching its elastic limit, unless the magnetic energy exceeds $2\times 10^{47}$ erg, which requires an average field strength of $2\times 10^{15}$ G. Thus, the strong magnetic field hidden in the crust is unlikely to cause outbursts. Furthermore, the magnetic field configuration can discriminate between central compact objects and magnetars.

13 pages, 7 figures

References in corpus (16)

• The Breaking Strain of Neutron Star Crust and Gravitational Waves
• Magnetic field dissipation in neutron star crusts: from magnetars to isolated neutron stars
• Evolution of a buried magnetic field in the central compact object neutron stars
• CCOs and the hidden magnetic field scenario
• Three-dimensional simulations of the magnetic stress in a neutron star crust
• Magnetic-field evolution in a plastically-failing neutron-star crust
• Evidence for the magnetar nature of 1E 161348-5055 in RCW 103
• Powering Central Compact Objects with a Tangled Crustal Magnetic Field
• Axisymmetric magneto-plastic evolution of neutron-star crusts
• Magnetic support for neutrino-driven explosion of 3D non-rotating core-collapse supernova models
• 3D Magneto-thermal Simulations of Tangled Crustal Magnetic Field in Central Compact Objects
• Magnetic-field evolution with large-scale velocity circulation in a neutron-star crust
• Accumulation of elastic strain toward crustal fracture in magnetized neutron stars
• Magneto-elastic equilibrium of a neutron-star crust
• Magnetic field sustained by the elastic force in neutron star crusts
• Strong toroidal magnetic fields sustained by the elastic crust in a neutron star