Abstract The response of the dawn-side auroral ionosphere and thermosphere to an imposed sudden enhancement of the convection electric field is investigated using a coupled thermosphere-ionosphere model. The conditions are intended to represent those thought to give rise to one form of high latitude trough. Joule heating, giving rise to thermal expansion of the atmosphere, combined with enhanced chemical reaction rates, rapidly generates an ionospheric trough, whose further decay is slowed by a large increase in hmF2. The neutral response to the event is complicated. At lower altitudes, neutral temperatures increase sharply and the zonal and meridional wind fields are as predicted in earlier work. At higher altitudes, neutral temperatures decrease in the region of greatest ion-neutral relative drift, as a result of adiabatic cooling. Both zonal and meridional neutral winds show unexpected responses, significantly different to lower altitudes, at later times in the event. In particular, zonal velocities decrease rather than increase, and meridional velocities develop a marked decrease on the equatorward side of the region of greatest relative velocity. These phenomena are still under investigation.
A study of the evolution of a high latitude trough using a coupled ionosphere/thermosphere model
Advances in Space Research ; 12 , 6 ; 161-169
1991-01-01
9 pages
Article (Journal)
Electronic Resource
English
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