Comparison between plasma densities measured with the AEROS-B and S3-l satellites and the IRI Model
Document ID: 55
Philbrick, C. Russell1
Lämmerzahl, P.2
Neske, E.3
Dumbs, A.3
1 USAF, Geophysics Laboratory, Hanscom AFB, Bedford, MA, U.S.A.
2 Max-Planck-Institut für Kernphysik, Heidelberg, F.R.G.
3 Fraunhofer-Institut für Physikalische Meβtechnik, Freiburg, F.R.G.
Abstract
Measurements by a mass spectrometer on S3-1 have been compared with those from an impedance probe and from a retarding potential analyzer on AEROS-B to investigate the relationship of the instruments' response to ionospheric total and partial densities. Conversion of the mass spectrometer data into absolute ion densities is based on a large number of correlated ionosonde observations of the f0F2 critical frequency. Results of the two different probes on AEROS were extensively intercompared and the impedance probe is considered to provide very accurate electron density. The perigees of the two satellites were both over the northern polar region in November 19 and many crossings at the same latitude and longitude occurred. Among these crossings, five cases were located which meet restrictive conditions minimizing the effects of spatial and temporal variability. The ratio of the densities measured when the two satellites were close to these crossing points exhibits a mean of 1.00 with 6% standard deviation, and the relative composition of molecular and atomic ions agrees within about 20%. Density variations were found to be correlated with invariant magnetic latitude rather than to strongly depend on altitude, in the Fregion. Data are compared to the International Reference Ionosphere model values for density and ion composition in the F-region.