Cosmic rays: the spectrum and chemical composition from $10^{10}$ to $10^{20}$ eV

Understand

The production of energetic particles in the universe remains one of the great mysteries of modern science.

• The mechanisms of acceleration in astrophysical sources and the details about the propagation through the galactic and extragalactic media are still to be defined.
• In recent years, the cosmic ray flux has been measured with high precision in the energy range from \energy{10} to \energyEV{20.5} by several experiments using different techniques.
• In some energy ranges, it has been possible to determine the flux of individual elements (hydrogen to iron nuclei).