Energetic particles in the inner Van Allen belt

A survey is given of the high energy particle populations in the inner radiation belt. The experiments which have given information about particles are discussed and the best experimental information about particle fluxes and spectra presented. Calculations are given which deal with the particles and indicate what particle sources and loss processes are most important. The role of neutrons in making the inner belt is considered in detail and the need for particle acceleration and/or other sources is shown.