  In this work we investigate and parameterize the amount and angular
distribution of Cherenkov photons which are generated by electromagnetic
cascades in water or ice. We simulate electromagnetic cascades with Geant4 for
primary electrons, positrons and photons with energies ranging from 1 GeV to 10
TeV. We parameterize the total Cherenkov light yield as a function of energy,
the longitudinal evolution of the Cherenkov emission along the cascade-axis and
the angular distribution of photons. Furthermore, we investigate the
fluctuations of the total light yield, the fluctuations in azimuth and changes
of the emission with increasing age of the cascade.
