Published online by Cambridge University Press: 25 April 2016
In recent years, cosmic-rays have become part of the study of astrophysics and the search for information as to their origin has assumed considerable importance. The question of the origin of the rays is linked with questions concerning their acceleration and propagation through interstellar space. The main problem facing the cosmic-ray astrophysicist in attempting to elucidate these questions observationally arises from the fact that most particles are electrically charged, causing their paths to be curved by the magnetic fields of the Earth and interplanetary and interstellar space.