abstract
It is shown that there is a good correlation between the fluxes of electrons with energies greater than 40 keV observed by Alouette I near the L shell 2,4 and the critical frequency of the E-layer observed at Argentine Islands, which lies on the same L shell. The increase of f0E observed agrees reasonably well with that calculated on the basis of a precipitated electron flux with characteristic energy 50 keV, of which the portion above 40 keV is observed by Alouette. lt is shown that the rate of ionization by the precipitated electrons can exceed that due to solar ultraviolet radiation at times.