The Significance of the Absence of Primary Electrons for Theories of the Origin of the Cosmic Radiation

Abstract

Electrons of energy above 5 Bev appear to constitute less than 0.4 percent of the primary cosmic radiation incident on the earth. An analysis of acceleration mechanisms reveals no distinctions can readily be made in acceleration per se on the basis of sign of charge or mass. The absence of high energy electrons must be explained on the basis of selective absorption. Bremsstrahlung collisions in the galaxy or the solar system and radiation caused by motion in galactic or local magnetic fields are inadequate to account for the large absorption of electrons compared with heavy particles. In collisions between energetic electrons and thermal photons losses approaching the total electron energy occur. An analysis of such collisions reveals that if cosmic rays are confined to the solar system hese collisions are so frequent that no electrons should be present at energies higher than 5 Bev. The photon density is too low in interstellar space to cause a similar removal of electrons there. These results favor the solar or stellar origin theories of the cosmic radiation.