Bottomside ionospheric density monitoring with SuperDARN HF radars

The Super Dual Auroral Radar Network (SuperDARN) is an international network of more than 30 ground-based, high-frequency (HF) space weather radars which continuously monitor the line-of-sight Doppler velocity of plasma irregularities at E- and F-region altitudes in the mid- to high-latitude ionosphere. We describe a new operating mode, based on the prior work of Hughes et al. [2002] and adapted for the current generation of SuperDARN radars, which is designed to collect oblique ionospheric sounding data in the down-time at the end of each 1- or 2-min radar scan. Selected results are shown from more than a dozen network-wide tests from 2020 to present, demonstrating how these multi-frequency observations are used for monitoring the bottomside ionospheric density response to space weather phenomena such as solar flares and solar eclipses.