The Enrico Fermi Schools, a cultural initiative promoted by the Italian Physical Society (SIF), were initiated in 1953 in a period that marked the beginnings of what is now called cosmic ray astrophysics. Indeed, the very first edition of the School focused on the contribution of cosmic ray physics to the laws of elementary particle physics. Almost seventy years later, another School has been focusing on the foundations of cosmic ray astrophysics, and this book contains the lectures presented as Course 208 of the prestigious International School of Physics Enrico Fermi, Foundations of Cosmic Ray Astrophysics, held in Varenna, Italy from 23 to 29 June 2022. Topics covered in the book range from particle acceleration to cosmic ray transport, and from radiation processes to feedback of cosmic rays in galaxy formation. In particular, a thorough description of the physics of cosmic ray transport in turbulent magnetic fields, and of the production of magnetic perturbations in the presence of cosmic ray gradients is provided, both these phenomena being essential in describing particle acceleration at shocks and the transport of cosmic rays within the galaxy. The transport of cosmic rays in different environments is also discussed. This area of research has received an extraordinary boost in recent times, thanks to the now unprecedented accuracy of observations, and to the possibility of testing new ideas and complex scenarios offered by recent developments in numerical simulation, and the book will be of interest to all those working in the field of high energy astrophysics.

This volume, marking the 20th Anniversary of the International School of Cosmic Ray Astrophysics, provides a wide-ranging overview of modern astrophysics ? from the infra-red to X-rays and ?-rays, from neutrinos to galactic cosmic rays, and from shock wave acceleration to cosmology. The separate topics contain both background information and the newest results in the field, making the discussion suitable for the nonexpert and the expert alike. Featured are high energy neutrinos (including the new generation of experiments coming on line), new results from X-ray astronomy and from the infra-red, particle acceleration in astrophysical plasmas, new results on the composition of cosmic rays (spanning six decades in energy), and cosmology.

A wide range of topics is covered in this book, ranging from supernovae to active galactic nuclei and cosmic gamma rays to neutrinos and dark matter.

In May 1998 a hundred renowned scientists from 20 different countries met at the Max-Planck-Institut für Aeronomie to communicate their latest results and ideas in astrophysical and space plasma, as a follow-up to previous similar meetings which were held in Varenna, Abastumai, Potsdam, Toki and Guaruja. The main papers emerging from this meeting are collected in this volume. They deal with fundamental plasma phenomena, particle and radiation processes in astrophysics and space physics as the origin of magnetic activity, the basic mechanisms of particle acceleration and plasma heating common to plasma in galaxies and at the sun as well as in planetary magnetospheres. New observational results from YOHKOH, SOHO and other missions are presented. Using these, the basic physical processes leading to coronal heating and solar/stellar wind acceleration are discussed. Other topics are the microphysics of shock waves and transport phenomena in collisionless plasmas and the physics of thin plasma boundaries. The volume also treats the ionic composition of plasma and dust in the Universe and their observability in the solar system. A CD-ROM is attached which adds a valuable multimedia component, illuminating results of observations, theory and simulations. Everyone interested in astrophysical plasmas, its radiation and charged particle aspects, and advanced or even beginning students will find references to nearly all modern aspects of plasma astrophysics and space physics as well as an overview of current research results.

In the first part, the book gives an up-to-date summary of the observational data. In the second part, it deals with the kinetic description of cosmic ray plasma. The underlying diffusion-convection transport equation, which governs the coupling between cosmic rays and the background plasma, is derived and analyzed in detail. In the third part, several applications of the solutions of the transport equation are presented and how key observations in cosmic ray physics can be accounted for is demonstrated.