On the probability of solar cosmic ray fluency during SEP event in dependence of the level of solar activity Original Research Article

We study the probability of fluency level of solar cosmic ray in different phases of solar activity. Information on fluency distribution is necessary for estimation of radiation hazard both in the space (satellites, interplanetary missions, space stations) and in atmosphere (aircraft level). We estimate probabilities of fluencies on the base of long time observation of proton flux (both direct measurements on the space detectors and on the base of recalculation from ground stations). Restored amplitude spectrum (distribution of events with given interval of amplitudes of the fluency or for fluencies more than given) allows to us estimate probability of dangerous states and extrapolate this distribution to rare events of extremely high amplitudes. Main source of data for this analysis is data from the Catalog of Shea and Smart for 31 year observations’ fluency in space (1990) and for detailed analysis – data from satellites GOES during the last 11 last years (1994–2004).