Aspects of layer electrodynamics inferred from high-resolution ISR observations of the 80–270 km ionosphere



The Arecibo 430 MHz Incoherent Scatter Radar (ISR) has been used to observe vertical ionospheric electron concentration profiles in the 80–280 km altitude region at the highest sustained resolutions (150 m, 10 s) thus far reported for “ion-line” measurements. We present results that reveal layers and wave-like features in unprecedented detail and likely point to electrodynamic processes linking the E and F regions. Tidal Ion Layers (TILs) and sporadic E (Es) layers in the 100–110 km altitude region often display significant peaks and edges that appear in only one range gate (150 m). Also, previously unreported wave-like plasma structures—termed “ion rain”—with ∼12 minutes apparent period, normalized amplitudes of 1–3%, and vertical wavelengths in excess of 30 km have been observed extending from base of the F-layer to the evening intermediate TIL with indications of coupling into the 90–110 km region below.