The Polar Cap and Outer Gap models of gamma-ray emission from rotation-powered
pulsars are examined. In the Polar Cap model, a detailed Monte Carlo calculation is
performed: Electrons and positrons are accelerated in vacuum gaps near the magnetic
polar cap of a rotating neutron star. The curvature radiation they emit interacts with
the strong magnetic field of the pulsar and produces e± pairs via the Sturrock process.
These pairs in turn emit synchrotron radiation which also interacts with the strong
magnetic field. An electromagnetic cascade results, and the gamma-ray flux seen
at the Earth consists of the escaping curvature and synchrotron radiation. In the
Outer Gap model, a much refined calculation of high energy emission from the outer
gap region is performed. In this case, vacuum gaps form in the outer regions of the
pulsar magnetosphere along the boundary between the “closed” and “open” field line
zones. The large potential drops which are postulated to form in the outer gaps
accelerate counter-streaming beams of electrons and positrons to highly relativistic
energies (Ee ~ 1013 eV). The curvature and inverse-Compton radiation emitted by
these particle beams interact with lower energy radiation to produce secondary pairs
of electrons and positrons. These secondary particles produce the synchrotron and
inverse-Compton radiation which provides the required photon-photon opacity for the
counter-streaming very high energy radiation. Improvements over previous outer gap
calculations include a more detailed treatment of the high energy emission processes
in the pulsar magnetosphere and the incorporation of particle and photon transport
to and from different emitting regions. For both the Polar Cap and Outer Gap
calculations, predictions of light curve shapes and spectral variation as a function of
pulse phase are made using standard assumptions about the geometry of the pulsar