  Pair cascades from millisecond pulsars (MSPs) may be a primary source of
Galactic electrons and positrons that contribute to the increase in positron
flux above 10 GeV as observed by PAMELA and AMS-02. The Fermi Large Area
Telescope (LAT) has increased the number of detected gamma-ray MSPs
tremendously. Light curve modelling furthermore favours abundant pair
production in MSP magnetospheres, so that models of primary cosmic-ray
positrons from pulsars should include the contribution from the larger numbers
of MSPs and their potentially higher positron output per source. We model the
contribution of Galactic MSPs to the terrestrial cosmic-ray electron / positron
flux by using a population synthesis code to predict the source properties of
present-day MSPs. We simulate pair spectra assuming an offset-dipole magnetic
field which boosts pair creation rates. We also consider positrons and
electrons that have additionally been accelerated to very high energies in the
strong intrabinary shocks in black widow (BW) and redback (RB) binary systems.
We transport these particles to Earth by calculating their diffusion and the
radiative energy losses they suffer in the Galaxy using a model. Our model
particle flux increases for non-zero offsets of the magnetic polar caps. We
find that pair cascades from MSP magnetospheres contribute only modestly around
a few tens of GeV to the measured fluxes. BW and RB fluxes may reach a few tens
of percent of the observed flux up to a few TeV. Future observations should
constrain the source properties in this case.
