Аннотация:The appearance of SEP events over a long-term time scale is described by the probability theory using some fundamental laws inherent in sets of SEP events. The basic of such laws is the character of relation between the mean rate of SEP events appearance and the level of solar activity.
The mathematical analysis of a set of most authentic experimental data on SEP events (appeared during the 21th, 22th and 23th cycles of solar activity), separated from the background radiation by physical (rather than technical) selection criteria, has shown that the mean rate of SEP events appearance is proportional to the solar activity level presented as a smoothed value of Wolf numbers (W). The probability of SEP events appearance for the given time interval is shown to be dependent only on the sum of monthly average or mid-annual Wolf numbers describing the solar activity for a sought time.