International School of Cosmic Ray Astrophysics <<Maurice M. Shapiro>>

21^st Course: Astroparticle Physics: Yesterday, Today, and Tomorrow
1-7 August, 2018

A historical introduction is given on cosmic rays since their first detection more than a century ago. The first lecture focuses on the direct measurements of charged cosmic rays mainly by balloon-borne and space-based instruments. The main detection techniques are reviewed spanning from the traditional passive detectors to modern and state-of-the-art active instrumentation (including magnetic spectrometers and calorimeters) relaying detailed digital information via dedicated downlinks to the ground stations. A review follows of the main experimental results on electron and positrons of cosmic origin and on the search for possible distinctive spectral features that could provide evidence for dark matter or the existence of astrophysical acceleration sources of electrons and positrons located close to Earth, at distances probably not exceeding the kpc scale. The most recent experimental results on the inclusive electron+positron spectrum are reported. In the second lecture, the cosmic-ray hadron sector is reviewed including the recent findings on deviations from a simple power-law of the differential energy spectra of light nuclei and the tantalizing similarity between the spectra of protons and positrons. Also, the relevance of accurate measurements of secondary-to-primary flux ratios for the validation of models of cosmic-ray transport in the galaxy is highlighted. Given the short time available, only a brief discussion is given on the theoretical interpretation of the data in the framework of current acceleration and propagation models. A concise summary of the main experimental results on anti-protons, on the elemental and isotopic composition of cosmic rays and on the relative abundances of trans-iron nuclei is also provided.