Comparison of theory with experiment for electron density distribution in the near wake of an ionospheric satellite

The angular distribution of thermal electrons in the very near wake of an ionospheric satellite computed according to the Liu and Jew theory is compared with experimental values. The space plasma parameters in the computation are based on in situ measurements performed by a Langmuir plate mounted flush on Explorer 31. The quantitative degree of agreement between results from this theory and results from an experiment based on data from eight passes that covered the entire range between perigee and apogee is demonstrated. It is found that for the maximum rarefaction zone most computed values of electron densities are lower than experiment values except at perigee altitudes. The theoretical and experimental limitations of such a comparison are specified, and its implications are discussed.