Comparison of plasma densities in the daytime polar F-region measured by the AEROS-B and S3-1 satellites

A comparative study of ionospheric measurements obtained by different sensors on two satellites has shown excellent agreement between the principal techniques used to measure the plasma density and ion composition. Results from an ion mass spectrometer on the S3-1 satellite and from an impedance probe and a retarding potential analyzer on the AEROS-B satellite have been compared for five cases that represent the closest coincidence of measurements that occurred during the satellite lifetimes. The crossings occurred at high polar latitudes and the studies have indicated that invariant latitude is more important than altitude, geodetic latitude, or geomagnetic latitude in systematizing the data. The ratios of the mass spectrometer ion densities to the impedance probe electron densities resulted in an average value of 1.00 with a standard deviation of 6%. The composition percentage for the molecular and atomic ions from the retarding potential analyzer agreed generally within about 20% of the mass spectrometer measurements.