[en] The results of studies of the exact steady-state nonequilibrium power-law solutions to the kinetic Boltzmann equation describing particle distribution functions characterized by a flux (source and sink) in momentum space are reviewed. A fundamentally new radioisotope method of current generation based on secondary-electron emission induced by α-particles passing through thin films is proposed. It is shown that devices in which the nonequilibrium electron distribution resulting from this process is used provide much higher current density compared to conventional thermionic generators. The results of investigations of the energy spectrum of the secondary electrons produced by α-particles from a radioisotope source are presented