Particle acceleration in pulsars and pulsar wind nebulae

Abstract

These notes summarise the contents of the lectures I delivered at the International School of Physics "Enrico Fermi" on "Foundations of Cosmic Ray Astrophysics". The lectures were dealing with the physics of Pulsars and Pulsar Wind Nebulae (PWNe) in the Cosmic Ray (CR) perspective. It has become now clear that the processes taking place in the environment of fast rotating, highly magnetized neutron stars, often detected as pulsars, play a crucial role in the formation of the CR spectrum detected at the Earth. These lectures discuss the main aspects of this connection. Pulsars are likely contributors of the CR lepton flux at the Earth thanks to their nature of electron-positron factories. Pulsars and their nebulae are the best potential leptonic PeVatron in the Galaxy, and the Crab Nebula, the prototype of the Pulsar Wind Nebula class is the only established PeVatron in the Galaxy. Pulsars are however also potential sources of high energy hadrons, up to the energies relevant for UHECRs. Pulsars and their nebulae are the best potential leptonic PeVatrons in the Galaxy, and the Crab Nebula, the prototype of the Pulsar Wind Nebula class, is the only established PeVatron in the Galaxy. Finally, regions of suppressed particle diffusion have been observed around evolved pulsars, the so-called TeV halos, which could have an impact on galactic CR transport. These lectures discuss the physics of pulsars and PWNe, summarising what we know about these systems and what pieces of information are still missing to fully assess their role in all the above mentioned Cosmic Ray connected aspects.