Magnetic fields and the P-P diagram for radio pulsars

Various mechanisms for the loss of angular momentum of neutron stars are an alyzed. Theoretical predictions about the evolution of the period are compa red with the observed distribution of pulsars on the log (P) over dot log(P ) diagram. Pulsars with short periods (P less than or equal to 0.1 s) canno t be fit well by any of the models considered. Their braking index is n = - 1, which requires the development of a new braking mechanism. The evolution of pulsars with P > 1.25 s is described by the law (P) over dot proportion al to P-2, probably due to processes internal to the neutron stars. The obs ervational data for pulsars with 0.1 < P less than or equal to 1.25 s can b e fit with a hybrid model incorporating internal processes and magnetic-dip ole losses. The magnetic fields in pulsar catalogs should be recomputed in accordance with the results obtained. For example, the magnetic fields obta ined for two magnetars with P = 5. Ih s and P = 7.47 s are B-s = 1.7 x 10(1 3) and 2.9 x 10(13) G, which are lower than the critical field B-cr = 4.4 x 10(13) G. For a substantial fraction of pulsars, their characteristic ages tau = P/2 (P) over dot cannot serve as measures of their real ages. (C) 20 01 MAIK "Nauka/Interperiodica".