title: Probabilistic model for fluences and peak fluxes of solar energetic particles.
abstract: The model is intended for calculating the probability for solar energetic particles (SEP), i.e., protons and Z=2-28 ions, to have an effect on hardware and on biological and other objects in the space. The model describes the probability for the > or = 10 MeV/nucleon SEP fluences and peak fluxes to occur in the near-Earth space beyond the Earth magnetosphere under varying solar activity.  The physical prerequisites of the model are as follows.  1. The occurrence of SEP is a probabilistic process.  2. The mean SEP occurrence frequency is a power-law function of solar activity (sunspot number).  3. The SEP size (taken to be the > or = 30 MeV proton fluence size) distribution is a power-law function within a 10(5)-10(11) proton/cm2 range.  4. The SEP event particle energy spectra are described by a common function whose parameters are distributed log-normally.  5. The SEP mean composition is energy-dependent and suffers fluctuations described by log-normal functions in separate events.
authors.affiliation: Institute of Nuclear Physics, Moscow State University, Russia. nymmik@srdlan.npi.msu.su
authors.forename: R A
authors.initials: RA
authors.lastname: Nymmik
mesh_terms: D003359:Cosmic Radiation; D005118:Extraterrestrial Environment; D005544:Forecasting / Q000379:methods*; D020450:Heavy Ions; D008433:Mathematics; D015233:Models, Statistical; D011336:Probability; D011522:Protons; D019445:Solar Activity
chemical_list: D011522:Protons