Charged particles in the inner Van Allen radiation belt

Abstract

A nuclear emulsion stack was flown through the lower part of the inner Van Allen radiation belt a few days after the intense solar flares of July 10 to 16, 1959. The stack looked out through a thin window on the mounting plate at the rear of the nose cone. Protons with incident energies down to 42 Mev were recorded. The total proton flux is about one-third that reported by Freden and White; the difference may be due to the lower peak altitude of the flight reported here. Above 100 Mev the proton spectrum is consistent with the neutron albedo hypothesis. Below 100 Mev, however, there is evidence of structure with a peak or plateau in the region of 80 Mev. This structure may be due to solar protons.