Cosmic Ray Astrophysics

The problem of the origin of cosmic rays is considered in an astronomical context and the current observational situation summarised. The evidence for acceleration in supernova remnants is critically examined. Key Words : Cosmic Rays, Supernova Remnants, Shock Waves I. INTRODUCTION Most astronomers regard cosmic rays as nothing more than a nuisance, an annoying and unwanted effect which disturbs their delicate photon detectors in unpredictable and irritating ways. However the origin of the cosmic rays is also one of the oldest major unsolved problems in modern astrophysics. Victor Hess discovered the existence of a very penetrating ionizing radiation coming from above the atmosphere, which we now call the cosmic rays, back in 1912 and the problem of understanding the nature and origin of this radiation has been a well-defined question since then. The only other open question which is equally specific and of similar antiquity is that of identifying the carrier(s) of the diffuse inters..