Evolution of energetic electron fluxes at the geostationary orbit during solar cycles 22 and 23. 27-day variations

In this paper, we consider variations in fluxes of energetic electrons at the geostationary orbit, which are related to the Sun's rotation period, during two solar cycles. We use data on fluxes of energetic electrons obtained from GOES (1986-2007) (>2 MeV) and LANL (1996-2007) (50-225 keV and 315-1500 keV) satellites. Within the solar cycle, we observed both periods of high recurrence of flux peaks during several rotations and periods of absent (or low) 27-day recurrence. The paper shows similarity and difference between manifestations of recurrences of fluxes from cycle to cycle. Insignificant manifestation of recurrence and its absence were observed mainly during solar maximum. High recurrence of electron fluxes was observed mainly at the stage of decline in solar activity (near solar minimum). We show that for both solar cycles there were several days (within the Bartels rotation) during which increased fluxes of energetic electrons would be most probably observed.