Ionosphere‐protonosphere thermal plasma fluxes estimated from Magion 2 and ionosonde data in August–September 1990

Abstract

The daytime thermal plasma fluxes at the topside of the midlatitude ionosphere were assessed during a quiet period and a recovery phase of a magnetic storm in summer 1990. Using in situ measurements of electron concentration and temperature and a crude estimate of mean ion mass performed by the Magion 2 subsatellite in an altitudinal range from 1200 to 2500 km, in addition to data supplied by ground‐based ionosondes, electron concentration profiles were drawn by means of a theoretical one‐dimensional steady state ionospheric model. Latitudinal variations of daytime ion fluxes at the 1000‐km‐height level during quiet periods revealed a peak at L = 2.5 ÷ 3.0 with maximum values up to 7 × 108 cm−2 s−1. The difference in flux versus latitude behavior between quiet and poststorm periods was clearly observable for L > 3. The uncertainty in the resultant ion fluxes depends upon the accuracy of the electron temperature and ƒoF2 measurements, as well as on the neutral wind velocity approximation, and was estimated to be about 50 percent. A comparison of the ion flows obtained with either direct measurements or indirect estimations made earlier show reasonable agreement.