Open AccessA numerical model of the ionosphere, including the E-region above EISCAT
Author(s) -
P.-Y. Diloy,
A. Robineau,
Jean Lilensten,
PierreLouis Blelly,
J. Fontanari
Publication year - 1996
Publication title -
annales geophysicae
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.522
H-Index - 93
eISSN - 1432-0576
pISSN - 0992-7689
DOI - 10.1007/s00585-996-0191-7
Subject(s) - ionosphere , incoherent scatter , electric field , ion , physics , convection , geophysics , computational physics , f region , ionization , atomic physics , atmospheric sciences , meteorology , quantum mechanics
It has been previously demonstrated that atwo-ion (O+ and H+) 8-moment time-dependent fluid modelwas able to reproduce correctly the ionospheric structure in the altitude rangeprobed by the EISCAT-VHF radar. In the present study, the model is extended downto the E-region where molecular ion chemistry (NO+ and O+2,essentially) prevails over transport; EISCAT-UHF observations confirmed previoustheoretical predictions that during events of intense E×Binduced convection drifts, molecular ions (mainly NO+) predominateover O+ ions up to altitudes of 300 km. In addition to this extensionof the model down to the E-region, the ionization and heating resulting fromboth solar insolation and particle precipitation is now taken into account in aconsistent manner through a complete kinetic transport code. The effects of E×Binduced convection drifts on the E- and F-region are presented: the balancebetween O+ and NO+ ions is drastically affected; theelectric field acts to deplete the O+ ion concentration. The [NO+]/[O+]transition altitude varies from 190 km to 320 km as the perpendicular electricfield increases from 0 to 100 mV m-1. An interesting additionalby-product of the model is that it also predicts the presence of a noticeablefraction of N+ ions in the topside ionosphere in good agreement withRetarding Ion Mass Spectrometer measurements onboard Dynamic Explorer