ELECTRONS AND POSITRONS IN THE GALACTIC COSMIC-RAYS

The detection of primary cosmic ray electrons with energies above 1 Te V implies the existence of a nearby, r less than or equal to 100 pc, a nd relatively young, t less than or equal to 10(5) yr, source(s) of ac celerated electrons. Therefore a correct treatment of the formation of the spectra of electrons during their propagation in the interstellar medium requires a separate consideration of the contribution of one ( or a few) nearby source(s) from the contribution of distant (R greater than or equal to 1 kpc) sources. To implement this approach, the prob lem of energy-dependent diffusive propagation of relativistic particle s from a single source is considered, and the analytical solution to t he diffusion equation in the general case of arbitrary energy losses a nd injection spectrum of primary particles is found. We show that in t he framework; of the proposed two-component approach, i.e., separating the contribution of the local (discrete) source(s) from the contribut ion of distant sources, it is possible to explain all the locally obse rved features of the energy spectrum of cosmic ray electrons from sub- GeV to TeV energies. In addition, assuming that the local source produ ces electrons and positrons in equal amounts, the model allows us to e xplain also the reported increase of the positron content in the flux above 10 GeV.