Incoherent back-scatter study of electron content and equivalent slab thickness

Abstract

Results of electron content and equivalent slab thickness obtained from radar backscatter measurements at Arecibo (18.4° N, 67° W) are presented and examined in the light of other simultaneously observed parameters, such as the height of the F-layer peak and electron and ion temperatures. There is a considerable day-to-day variability both in the electron content and the equivalent slab thickness. The daytime electron content shows a strong positive correlation with the height of the F-layer peak, hmF2, which seems to be due to decrease in the integrated loss rates with increasing peak height. The post sunset decay of the electron content provides a mean effective attachment coefficient of 8× 10^-5 sec ^-1.The post midnight enhancements, observed mainly during the winter nights, require downward electron fluxes of about 2.5× 10¹²m^-2sec^-1 at the height of 700 km. The slab thickness during the nighttime shows a strong dependence upon hmF2 and is very closely related to the neutral scale height at the peak. The daytime slab thickness, however, is controlled jointly by the neutral scale height and the extent of thermal nonequilibrium.