Engineering topics
Publications and source records attributed to Schofield, N. J..
Data from Earth-orbiting spacecraft at geostationary and higher altitudes was cataloged. Three lunar-orbiting spacecraft and some others whose apogees did not attain the geostationary altitude are included.
A summary and intercomparison of recent inner radiation zone electron data are presented. The morphology of the inner radiation zone is described and the data compared with the current generation of inner zone trapped electron models. An analytic representation of the inner zone equatorial pitch angle distribution is presented. This model was based upon data from eight satellites and was used to reduce all data to the form of equatorial flux. Although no Starfish-free high energy electron measurements were available from the inner portion of the inner radiation zone, it was found that the AE-6 model provided a good description of the present solar maximum environment.
A review of the temporal variation in the trapped electron population of the inner and outer radiation zones is presented. Techniques presently used for modeling these zones are discussed and their deficiencies identified. An intermediate region is indicated between the zones in which the present modeling techniques are inadequate due to the magnitude and frequency of magnetic storms. Future trends are examined, and it is suggested that modeling of individual magnetic storms may be required in certain L bands. An analysis of seven magnetic storms is presented, establishing the independence of the depletion time of the storm flux and the storm magnitude. Provisional correlation between the storm magnitude and the Dst index is demonstrated.
Relative abundances of cosmic-ray He-3 and He-4 nuclei in the 125-210 MeV/nucleon energy range are reported from balloon data. The He-3 spectrum above roughly 40 MeV/nucleon can be derived from the He-4 spectrum. Predicted and observed He-3 spectra are compared, with solar modulation taken into account, to interstellar He-4 spectra. It is concluded that conventional interstellar He-4 spectra cannot simultaneously reproduce high-energy and low-energy He-4 fluxes seen at earth in 1972, and medium-energy and low-energy He-4 fluxes seen at earth in 1972.