CRRES observations of radiation belt protons - 1. Data overview and steady state radial diffusion

The Proton Telescope (PROTEL) instrument on the CRRES satellite made measurements of omnidirectional differential proton flux in the energy range 1-100 MeV, with full pitch angle resolution. An overview of the equatorially mirroring particle data is presented for the entire CRRES mission. We then consider the equatorially mirroring particle distribution in terms of steady state radial diffusion theory. The outer zone, 1.7 less than or equal to L less than or equal to 3, is shown to have deviated drastically from steady state profiles both before and after the magnetic storm of March 24, 1991, which rearranged the outer zone but left the inner zone, L less than or equal to 1.7, largely unaffected. Time-averaged measurements are compared to theoretical steady state diffusion profiles of the inner zone, which are calculated using several different, previously introduced models of the plasmaspheric electron density and cosmic ray albedo neutron decay (CRAND). For each combination of models, a four-parameter (electrostatic plus magnetic) radial diffusion coefficient is sought which minimizes the difference between the measurements and calculated flux values. While the best fit values found are physically implausible, nearly equally good results are obtained for values only moderately adjusted from standard, consensus values.