Time‐averaged fluxes of heavy ions at the geostationary orbit

Abstract

Measurements of average proton, helium, carbon, and oxygen fluxes at 6.6 RE are reported. The data represent averages obtained on ATS 6 between June 15 and October 3, 1974. The energy range covered was 0.36–1.1 MeV for protons and approximately 1–4 MeV for the heavier ions. The results indicate that above about 1 MeV the heavier ion fluxes dominate over the proton flux on the energy/ion scale. Using two different spectral dependencies to fit our data, we find the carbon to oxygen concentration ratio for energies above 1 MeV to be 0.43 for the power law spectrum and 0.44 for the exponential spectrum. Thus in either case we find the abundance ratio consistent with the solar origin of the particles. Similarly, the helium to oxygen concentration ratio is found to be 0.17 for the power law spectrum and 0.28 for the exponential spectrum. This is inconsistent with the solar wind ratio, which is about 10. The results quoted above are based on a very small portion of the distribution function above 1 MeV.