A numerical model of ion kinetics is considered for the axially symmetrical magnetic trap. The trap contains warm Maxwellian plasma and strongly non-Maxwellian high-energy (fast) ions. The steady-state fast ion population is supported by the ionization of high-energy neutral atoms injected into the plasma. The physical model is based on the kinetic equation with the two-dimensional Fokker–Planck collision operator in the velocity phase space. Regimes of plasma exhaust through the mirrors are considered taking into account the possibility of electrostatic barrier formation. Parameters of power balance are discussed for the system under consideration.