The cosmic ray electron/proton intensity ratio between 1965 and 1979

In experimental investigations, differences have been found regarding the modulation of low-energy electrons and protons. These differences cannot be explained on the basis of conventional theory. Evenson et al. (1979) have attempted to relate the differences in the modulation of electrons and protons to the solar field reversal of 1969-1971. The analyses have been inconclusive due to lack of a long time base and to a scarcity of reliable electron data. The present study represents an extension of he investigation of Evenson et al. (1979) to the time period 1965-1979. New data obtained in 1977-1979 are added, 1965 electron data are reexamined, and the time behavior of the helium/proton ratio is considered. It is concluded that there was a systematic shift in the intensity ratio of low-energy electrons to protons in the time period around the reversal of the solar polar magnetic field, leading to a clear difference in the values of the ratio for the two consecutive solar minima 1965 and 1976.