Phenomenology and theory of galactic cosmic-ray propagation

Understanding the cosmic-ray (CR) transport in the Milky Way magnetic field is fundamental to unveil their galactic factories. While we know now that they can be created in supernovas, there may be other sources available for CR acceleration. To trace back CR origins we can look at what they are made of. By weighing the different isotopes of elements that hit CR detectors, we can infer global properties as the galactic grammage and escape time. These quantities are then crucial to test any more fundamental description of the transport of charged particles in the interstellar plasma and to assess the contribution of any exotic mechanism to the anti-matter fluxes. The AMS-02 mission is scrutinising the CR composition with an unprecedented sensitivity, also revealing unexpected new features in the element spectra. While these fresh puzzles are thriving unorthodox novel approaches, the old-fashioned Galactic halo model is striving to survive.