Ionospheric Sluggishness

A systematic time delay between peak incoming solar radiation during a solar flare and peak electron density in the ionosphere is known as ionospheric sluggishness. Ionospheric sluggishness is known to be maximized around D-region heights (~60-90 km altitude). This article is our first attempt to estimate ionospheric sluggishness using high frequency (3 - 30 MHz) instruments. In addition, we statistically characterize the observed sluggishness and provide an insight into D-region photochemical processes. In this article, we also demonstrate how to extract the D-region’s recombination coefficient using a theoretical model and measured sluggishness.