How well do we understand the properties of Galactic CR propagation and acceleration ? A critical view.

Discussion timeslot (ZOOM-Meeting): 15. July 2021 - 18:00
ZOOM-Meeting URL: https://desy.zoom.us/j/98542982538
ZOOM-Meeting ID: 98542982538
ZOOM-Meeting Passcode: ICRC2021
Corresponding Session: https://icrc2021-venue.desy.de/channel/44-The-Origins-of-Galactic-Cosmic-Rays-GAD-GAI-CRD/125
Live-Stream URL: https://icrc2021-venue.desy.de/livestream/Discussion-04/5

Abstract:
'The Galactic cosmic ray (CR) fluxes observed in the vicinity of the Earth encode the space and time averaged properties of their sources and are also shaped by the effects of their propagation in the Galaxy.rnA combined study of the spectra of different particle types (protons, primary and secondary nuclei, electrons, positrons and antiprotons) is essential to determine the roles of the source and of propagation in the formation of the fluxes.rnSeveral authors are now claiming that these combined studies have essentially solved the problem, and that the source spectra for all particle types are now well determined in a broad energy range, with significant uncertainties only at high energy.rnThis conclusion obviously also imply that also the CR propagation is well understood.rnIn this contribution we analyze critically these results, and conclude that the problem of determining in good approximation the average CR source spectra (and therefore also the main properties of CR propagation)remains open, with very large uncertainties.rnSolving this problem has profound implications for the properties of the Galactic CR accelerators (that have not yet been firmly identified) and for our understanding of the Milky Way magnetic structure.rnFuture observations, especially of electrons and positrons in the multi--TeV range and of unstable isotopes like Beryllium in the few GeV range should soon allow to solve the problem.'

Authors: Paolo Lipari
Indico-ID: 1022
Proceeding URL: https://pos.sissa.it/395/169