Wilmot N. Hess

Energetic particles in the inner Van Allen belt

A survey is given of the high energy particle populations in the inner radiation belt. The experiments which have given information about particles are discussed and the best experimental information about particle fluxes and spectra presented. Calculations are given which deal with the particles and indicate what particle sources and loss processes are most important. The role of neutrons in making the inner belt is considered in detail and the need for particle acceleration and/or other sources is shown.

Source of Outer Zone Protons

In the L = 2 to 5 range in the outer radiation belt, DAVIS et al. (1964) find that the spectra of the relatively stable 0.1 to 5 MeV protons show smooth but large variations with L and equatorial pitch angle, α0, as in Figure 1. Protons near Open image in new window Fig. 1 Low energy proton spectra at various distances from the earth, from Davis and Williamson (1963).

Conclusions on Neutron Albedo Decay Source

At the end of the Session, Dr. MCCORMAC requested that the chairman try to summarize the experimental material presented dealing with neutron decay. Dr. HESS put the following chart (Table I) on the board as his estimate of the findings of the significant experiments. He stated that the definition of agreement that he was using was “agreement within a factor of three”.