On the nature of the cosmic ray positron spectrum

A new calculation has been made of the flux of secondary positrons above 100 MeV expected for various propagation models. The models investigated are the leaky box or homogeneous model, a disk-halo diffusion model, a dynamical halo model, and the closed galaxy model. The parameters of these models have, in each case, been adjusted for agreement with the observed secondary/primary ratios and Be-10 abundance. The positron flux predicted for these models is compared with the available data. The possibility of a primary positron component is considered.