Cyclic variations of solar proton activity and solar proton events

Radiation conditions on the near-the Earth orbits of satellites starting from 1965 and up to 1993 were studied. The 22-nd cycle of solar activity is determined to differ from the 20-th and 21-st cycles in heliogeographical and radiation parameters. Essentially higher number of periods of radiation condition perturbances is observed in the near-the-earth space. Peculiarities of flares-sources responsible for variations of radiation characteristics by solar cycles and for radiation perturbations, are studied. 11 refs.; 4 figs.; 1 tab