Combining diffusion equation solutions with direct Monte-Carlo simulations of charged particle trajectories, the propagation of cosmic rays in the Galaxy is investigated. Different assumptions on the shape of the regular Galactic magnetic fields and source distributions are considered and their influence on cosmic-ray life-times and the energy spectrum obtained at Earth is examined. The origin of the knee in the energy spectrum at 410^15 eV and the second knee at 410^17 eV is discussed. In particular, it is investigated whether the knee can be explained by propagation effects only and if the second knee is due to the end of the galactic component with a strong contribution of elements heavier than iron.

Proceedings of the 30th International Cosmic Ray Conference; Rogelio Caballero, Juan Carlos D'Olivo, Gustavo Medina-Tanco, Lukas Nellen, Federico A. Sánchez, José F. Valdés-Galicia (eds.); Universidad Nacional Autónoma de México, Mexico City, Mexico, 2008; Vol. 4 (HE part 1), pages 261-264