A predictive model of worst case solar proton event fluences is presented.
It allows the expected worst case eve nt fluence to be calculated for a giv
en confidence level and fbr periods of time corresponding to space missions
. The proton energy range is from > 1 to > 300 MeV, so that the model is us
eful for a variety of radiation effects applications.
For each proton energy threshold, the maximum entropy principle is used to
select the initial distribution of solar proton event fluences. This turns
out to be a truncated power law, i.e., a power law for smaller event fluenc
es that smoothly approaches zero at a maximum fluence. The strong agreement
of the distribution with satellite data for the last three solar cycles in
dicates this description captures the essential features of a solar proton
event fluence distribution.
Extreme value theory is then applied to the initial distribution of events
to obtain the model of worst case fluences.