•P. Homola1, D. Gora1, D. Heck2, H.
Klages 2, J. Pekala1, M. Risse2, B. Wilczynska1
und H. Wilczynski1
1H.Niewodniczanksi Institute of Nuclear Physics, 31-342
Krakow, Poland
2Forschungszentrum Karlsruhe, Institut für Kernphysik,
Postfach 3640, 76021 Karlsruhe
The origin of cosmic rays at the highest energies is still unclear.
In some so-called top-down scenarios, a considerable fraction of particles
at energies exceeding 10 EeV are predicted to be photons. Photons at such
high energies can interact with the Earth's magnetic field, forming an
electron-positron pair, which in turn emits synchrotron radiation. In this
way, instead of a single high-energetic particle, a bunch of particles
enters as a preshower the atmosphere, which influences the characteristics
of the air shower formed. In the simulation code CORSIKA, this preshowering
has been included. The preshower physics is reviewed and results of the
complete CORSIKA simulations are presented. Implications for the detection
of air showers initiated by high-energy photons are discussed.