Orientation of magnetic axis of pulsars and its evolution.

The relationship between pulsar age and the angle (beta) between the magnetic and spin axes of the neutron star is investigated on the basis of published data on 56 pulsars from the list of Manchester and Taylor (1981). The method of Kuz'min and Dagkesamanskaia (1983) is modified to account for curvature (as proposed by Manchester and Taylor, 1977) and permit the computation of both beta and epsilon, the angle between the magnetic axis and the observing direction. The calculated values of beta and epsilon are presented in tables and graphs and shown to confirm a decline of beta with pulsar age, and subpulse parameters are determined for six selected pulsars. The height of the 400-MHz emission region in the pulsar magnetosphere is estimated as r(400) = 150 km.