ON THE NATURAL ENERGETIC POSITRON POPULATION IN THE EARTHS INNER RADIATION BELT

Anti-particles may coexist with particles in the rarefied energetic pa rticle and plasma environments of the magnetized planets. We consider here the possibility that a naturally generated belt of positrons may be part of the terrestrial radiation environment. It is suggested that energetic positrons of MeV energies can be produced in inelastic nucl ear reactions resulting from energetic collisions between the geomagne tically confined population of relativistic protons and the residual t errestrial atmosphere and exosphere. The spatial location of the produ ction of these positrons would thus most likely be the inner radiation zone on L-shells well below L = 2.0. In this work we present a comput ed positron source function, and we assess the longevity and probable ambient abundance of these positrons in the 10-100 MeV energy range ar ound L = 1.2. The theoretical predictions are then compared with avail able experimental measurements of magnetospheric positrons. Copyright (C) 1996 Elsevier Science Ltd.