Ultra-high energy cosmic rays: sources, acceleration processes and GZK phenomena

Ultra-high energy cosmic rays (UHECR) reach an energy of 1020 eV, which is a million times higher than the energy achieved in artificial particle accelerators. The arrival of high-energy particles from space occurs infrequently, so detectors with a large area are required to register such events. It is necessary to understand what known effects can accelerate and decelerate particles to such energies. The upper energy limit is the Greisen-Zatsepin-Kuzmin (GZK) effect. This process significantly limits the possible distance to sources, and it should lead to suppression of the high-energy part of the spectrum. This work analyzes the GZK effect for nuclei from hydrogen to iron