A bounce-averaged ring current kinetic model for arbitrary pitch angle, including losses due to charge exchange and Coulomb collisions along ion drift paths, is developed and solved numerically. Results from simplified model runs, intended to illustrate the effects of adiabatic drifts and collisional losses on the proton population, are presented. The processes of i) particle acceleration under the conditions of time-independent magnetospheric electric fields; ii) a predominant loss of particles with small pitch angles due to charge exchange; and iii) a buildup of a low-energy population caused by the Coulomb drag energy degradation, are discussed. ¿ American Geophysical Union 1994