What are Cosmic Rays?
- Mostly protons, with some heavier nuclei, such as C, O, and Fe.
- Energies up to ~10^21 eV.
Flux scales roughly as E^(-3)
- Sources:
- Solar: ions in the solar wind, accelerated up to ~10^7 eV/amu or higher.
- Galactic: iron and other elements released in supernovae
and accelerated in shock fronts.
- Extra-Galactic: AGN may be the source of some ultra-high-energy cosmic rays
(UHECRs) in the ~10^16 - 10^21 eV range.
- High energy cosmic rays (UHECRs) do not penetrate the atmosphere.
They collide multiple times in the atmosphere, creating a shower of
lower-energy particles.