The effect of photon capture and field ionisation on high magnetic field pulsars

We have investigated the formation of polar gaps in pulsars as envisaged by Ruderman and Sutherland (1975) in the presence of photon conversion into positronia (Shabad and Usov, 1985; Heroldet al., 1985) and dissociation of positronia by strong electric fields. For the emission of curvature radiation near the pulsar's surface, we have used formulae which are valid in the extreme relativistic regime. We find that the gap formation is not affected, only the gap height is generally slightly increased. In the sample of pulsars that we have studied, in most cases there is likely to be enough plasma in the gap to initiate processes producing radio emission in accordance with the theory. In some cases we found the possibility of emission of high-energy photons outside the pulsar magnetosphere, as was suggested earlier by us (Bhatiaet al., 1987) in conformity with some of the observations.