  The turbulence and spatial nonuniformity of the guide magnetic field cause
two competitive effects, namely, the scattering effect and the adiabatic
focusing effect, respectively. In this work, we numerically solve the
five-dimensional Fokker-Planck transport equation to investigate the radial
evolutions of these important effects undergone by the solar energetic
particles (SEPs) propagating through interplanetary space. We analyze the
interplay process between the scattering and adiabatic focusing effects in the
context of three-dimensional propagation, with special attention to the
scenario of the outer heliosphere, in which some peculiar SEP phenomena are
found and explained. We also discuss the radial dependence of the SEP peak
intensities from the inner through outer heliosphere, and conclude that it
cannot be simply described by a single functional form such as R^{-\alpha} (R
is radial distance), which is often used.
