Propagation of Cosmic-Ray Nuclei in a Diffusing Galaxy with Convective Halo and Thin Matter Disk

A diffusion model for cosmic-ray propagation in the galaxy that includes the effects of convection in the halo is presented. Calculations are made for 13 primary and secondary nuclei with rigidities between 1 and 1000 GV using interaction loss rates, secondary production rates, and radioactive decay on the basis of recent new cross-section measurements. It is found that, in order to fit the rather weak radial dependence of cosmic-ray protons derived from gamma-ray data, the radial profile of the cosmic-ray sources must also have a weak radial dependence. It is suggested that convection perpendicular to the disk of the Milky Way Galaxy may not be important even at rigidities less than a few GV. The obtained limits on halo thicknesses are consistent with what can be determined for the distribution of cosmic-ray electrons in the halo based on the distribution of radio synchrotron emission in this and other galaxies.