On the spin-down of young neutron stars

The Rotation Powered-Pulsars (RPPs) are exposed to a long-term changes in the period of rotation, which are measured by the frequency and its derivatives, Omega, (Omega) over dot, (sic), obtained from timing observations. The parameter that links these observables with pulsar deceleration is the braking index, n, which is exactly 3 for purely dipolar radiation. Few braking indices have been estimated to date, for very young pulsars, and in all cases, n < 3. These observations suggest that there are complex plasma processes in the magnetosphere of the pulsar that are not fully well understood. In the present work we revisit the magnetic torque problem for young pulsars in the approach of magnetic field growth due ohmic diffusion. We show that such approach could explain the low values of n in very young neutron stars and may be relevant to explain why a small group of neutron stars, found in young supernova remnants or CCOs, exhibit little or no evidence for the presence of a magnetic field.