Propagation of super-high-energy cosmic rays in the Galaxy

The propagation of high-energy cosmic rays in the Galaxy is investigated. Solutions of a diffusion model are combined with numerically calculated trajectories of particles. The resulting escape path length and interaction path length are presented and energy spectra obtained at Earth are discussed. It is shown that the energy spectra for heavy elements should be flatter as compared to light ones due to nuclear interactions during the propagation process. The obtained propagation properties of ultra-heavy elements indicate that these elements could play an important role for the explanation of the second knee in the cosmic-ray energy spectrum around 400 PeV.