Cosmic-ray positrons produced by pulsar winds from mature gamma-ray pulsars

In the frame of the gamma -ray pulsar outer gap model, e(+/-) pairs in the pulsar magnetosphere are produced by the cascade of e(+/-) pairs through sy nchrotron radiation of the return current fi om the outer gap. These pairs are accelerated mono-energetically to relativistic energies in the pulsar w ind driven by low-frequency electromagnetic waves. Using Monte Carlo simula tions, we generate a sample of the mature gamma -ray pulsars in our Galaxy and calculate the positron production rate from these pulsars. With a simpl e leaky box model, we calculate the ratio of cosmic-ray positron to total e lectrons. Our result indicates that the pulsar contribution to the cosmic-r ay positron peaks at about 40 GeV and the observed e(+)/(e(-) + e(+)) ratio can be explained by this model.