Direct Evidence for the Dissipation of Small-Scale Ionospheric Plasma Structures by a Conductive E Region

摘要

The conductivity of the ionospheric E region is known to cause effective dissipation of plasma structures in the F region.We use 3.5 years of 16-Hz sampling rate electron density measurements from the Swarm advanced data set to investigate seasonal dependencies of plasma structure dissipation. Using a novel algorithm to infer plasma structure dissipation through detection of spectral breaks in density fluctuation power spectra, we analyze 100,000 spectra based on data from Swarm A in both the northern and southern polar caps. For the first time, we can present long-term development of small-scale (~1-10 km) plasma structure diffusion in the high-latitude ionospheric F region.We discuss possible reasons for these variations. This study presents evidence for the E region as an important factor in the seasonal variation of F region plasma irregularity amplitudes.