Description:

Title: New Insights on the Origin of Cosmic Rays

Speaker: Damiano Caprioli, University of Chicago

Abstract: The origin of extraterrestrial energetic particles (usually referred to as “cosmic rays”) has puzzled scientists since the pioneering discovery by Victor Hess in 1912. In the last decade, however, modern supercomputers have opened a new window on the processes regulating space and astrophysical plasmas, allowing the study of particle acceleration via first-principles kinetic simulations. I present state-of-the-art particle-in-cells simulations of non-relativistic shocks, in which ion and electron acceleration efficiency and magnetic field amplification are studied in detail as a function of the environmental parameters. I then discuss the theoretical and observational counterparts of such findings, comparing them with in-situ measurements at shocks in the heliosphere (especially the Earth’s bow shock) and with multi-wavelength observations of astrophysical objects such as supernova remnants and galaxy clusters. Finally, I present an original mechanism for the acceleration of the highest energy cosmic rays, up to 10^20eV, in the ultra-relativistic jets of powerful blazars, outlining how it naturally reproduces the latest results of the Pierre Auger Observatory.

Host: Tchekhovskoy

Speaker Schedule

Keywords: Physics, Astronomy, colloquium