The influence of nondipolar magnetic field and neutron star precession on braking indices of radiopulsars

Abstract

Some radiopulsars have anomalous braking index values It is shown that such anomalous values may be related to nondipolar magnetic field. Precession of a neutron star leads to rotation (in the reference frame of the star) of its angular velocity Ω around the direction of neutron star magnetic dipole m with an angular velocity Ωp. This process may cause altering of electric current flowing through the inner gap and consequently the current losses on the time-scale of precession period Tp= 2π/Ωp. It occurs because the electric current in the inner gap is determined by Goldreich-Julian charge density ΡGJ=-Ω·B/(2πc), that depends on the angle between direction of small scale magnetic field and the angular velocity Ω. © 2010 The Authors. Journal compilation © 2010 RAS.