Solutions of the spherically-symmetric cosmic-ray transport equation in interplanetary space

Numerical solutions of the well-known spherically-symmetric transport equation for interstellar cosmic rays in the interplanetary medium are presented. It is shown: (a) why nuclei and electron modulations differ, (b) that it is easy to read more in the model than it contains, (c) that the only significant parameter that determines the level of modulation is the product of the solar wind speed and the number of diffusion mean free paths between observer and boundary, and (d) that observations do exist which cannot be explained in terms of this simple model.