Cosmic Ray Propagation Studies With GALPROP

Various space-based and balloon-borne experiments have reported significant spectral hardening of cosmic ray data at around 200 GV. This spectral feature is seen in many different cosmic ray spectra, including primary and secondary elements. The numerical cosmic-ray propagation code GALPROP was used to investigate this spectral hardening. The Plain Diffusion model with reacceleration effects serves as a base model. Using rigidity-dependent parameters, three cases were studied: one with a diffusion coefficient break, one with source spectrum breaks, and one with a combination of both effects. An additional positron source was also investigated to explain the positron excess above ~27 GeV. Comparisons of elemental spectra and ratios for the three cases will be presented. The limitations of these three cases and plans for improvements will also be discussed.