Braking index and period--pulse-width distribution of pulsars

The braking index n and the period-pulse-width distribution of pulsars are reinvestigated by relaxing the conventional assumption that Ry = RL, where Ry is the radius of the neutral points marking the transition from closed to open field lines, and RL is the radius of the "light cylinder." This assumption is replaced by the relation Ry = R' flRL", where R is the radius of the neutron star. It is found that a good fit to the period-pulse-width distribution can be obtained for in the range 0.5 < ,; < 0.7. The relation n = I + 2 then gives n = 2 2 + 0 2 which is in good agreement with values measured for the Crab pulsar. This model implies that one or two pulsars should show an interpulse, in agreement with observation (two). This model leads to new estimates of the surface magnetic field strength B of pulsars, giving B = 10112 gauss for the Crab pulsar, and indicates that pulsar magnetospheres are subject to irregular changes associated with irregularities in period.