The slab thickness of the mid-latitude ionosphere

摘要: Abstract The thickness of the peak ionosphere depends primarily on temperature T n neutral gas, and corresponds approximately to an α-Chapman layer at a 0.87T . overall slab thickness, as given by Faraday rotation measurements, is then τ =0.22 + 7km. Expansion topside ionosphere, changes in E-andFl-regions increase about 20 km during day summer. Near solar minimum increased lowering O /H transition height; if estimated, this height can be obtained from observed values τ. Hourly were determined over period 6 yr 34°S 42°S. maximum night-time 260 all seasons. corresponding temperatures agree with satellite drag values; they show semiannual variation 14 per cent seasonal change 5 cent. Daytime 230 winter 320 summer, implying 30 Temperatures steadily throughout seasons, rapid post-sunset cooling Downwards movements produce large 0600 hr winter. A upwards flux, equal 40 (limiting) value, reduces for several hours after sunrise increases near showing reduction 700 summer 500