Propagation model for cosmic ray species in the Galaxy

In a recent paper [Astrophys. J. 565 (2002) 280], it has been shown that the flux of secondary cosmic ray (CR) antiprotons appears to be contradictory to measurements of secondary to primary nuclei ratios in cosmic rays when calculated in the same Galactic propagation model. The contradiction appears as a value of the diffusion coefficient necessary to match the secondary ratios p¯/p and B/C. In particular, it was shown that the reacceleration models designed to match secondary to primary nuclei ratios produce too few antiprotons. It is, however, clear that some reacceleration is unavoidable in the turbulent interstellar medium. Here we discuss an idea of how to improve reacceleration model by allowing for the damping of interstellar turbulences on the small scale by cosmic rays, mostly protons. This would lead to increase in the mean free path lengths at low energies, the well-known phenomena empirically discovered in the Leaky-Box models, thus producing less secondary nuclei. The effect on secondary antiprotons will be discussed elsewhere.