ABSTRACT
The greatest acceleration mystery of all remains that of the acceleration of cosmic rays. Cosmic rays are charged particles-predominantly protons, but with an admixture of heavier nuclei, electrons and positrons-which pervade, it is believed, the whole Cosmos [49, 234]. They enter the solar system from sources and acceleration regions located throughout the galaxy and very probably beyond. In the case of the protons and heavier nuclei, energies range from the lowest capable of penetrating the magnetic field of the heliosphere i.e. ~ 106 eV, to the highest energies known to be attained by individual nuclei, i.e. 1020 eVand possibly even beyond this [235]. Our study of cosmic-ray electrons, or perhaps better just cosmic electrons, which though very energetic do not reach these extreme energies, will nevertheless raise many of the key issues related to the origin of the nuclei as well. It may as well be admitted at the outset that the problem is quite baffling.
