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Session: Cosmology and Relativistic Astrophysics

Name: Mr. Dimitrios Skiathas (University of Patras)
Coauthors: No coauthors were included.
Type: Oral
Title: Simulations of magnetic field evolution in crusts and cores of neutron stars. The impact of ambipolar diffusion.
Abstract:

Magnetic fields in neutron stars are responsible for a variety of spectacular phenomena ranging from flares to gamma-ray and fast radio bursts. The evolution of the magnetic field in neutron stars is driven by three mechanics, Ohmic dissipation, Hall effect and ambipolar diffusion. The strength of each mechanism, depends on the electron number density, the electric conductivity and the properties of the interactions between the different particles, thus it is not the same in the whole region of the neutron star. Ohmic dissipation and Hall effect drive the evolution of magnetic field in the crust, while ambipolar diffusion dominates the evolution of the magnetic field in the core of strongly magnetized neutron stars. The evolution of the magnetic field in a neutron star under the effect of ambipolar diffusion is the focus of our study. We have developed a code to integrate the induction equation, by discretizing it using a central finite difference scheme, on an axisymmetric domain. We simulate the evolution, both in the crust and the core of the neutron star, for four different configurations of the initial magnetic field: a pure poloidal field, a pure toroidal field, a mixed field and the case where the toroidal field is confined in the region of closed poloidal field lines. We investigate the influence of ambipolar diffusion in the evolution as well as the final state of the magnetic field. The consequences of the evolution is that the toroidal field is driven near the crust – core interface, inside the region of closed poloidal field lines.