Estimation of solar energetic proton mission‐integrated fluences and peak intensities for missions traveling close to the Sun

Abstract

A method to estimate both solar energetic particle mission‐integrated fluences and solar energetic particle peak intensities for missions traveling through the innermost part of the heliosphere (r < 1 AU) is presented. By using (1) an extensive data set of particle intensities measured at 1 AU over the last three solar cycles, (2) successive launch dates for the mission traveling close to the Sun over the time interval spanned by our data set, and (3) appropriate radial dependences to extrapolate fluences and peak intensities measured at 1 AU to the heliocentric radial distance of the mission at each specific time, we generate distributions of both mission‐integrated fluences and maximum peak intensities. From these distributions we extract the values of mission‐integrated fluence and maximum peak intensity at a required confidence level. Results of this method applied to the specific case of the nominal prime mission of Solar Probe Plus are shown.