Application of wide-beam transmission for advanced operations of SuperDARN Borealis radars in monostatic and multistatic modes

The Super Dual Auroral Radar Network (SuperDARN) consists of more than 30 monostatic high-frequency (HF, 8-20 MHz) radars to study dynamic processes in the ionosphere. SuperDARN provides maps of global-scale ionospheric plasma drift circulation from the mid-latitudes to the poles. The conventional SuperDARN radars consecutively scan through 16 beam directions with a lower limit of 1 minute to sample the entire field of view. In this work, we use the advanced capabilities of the recently developed Borealis digital SuperDARN radar system. Combining a wide transmission beam with multiple narrow reception beams allows us to sample all conventional beam directions simultaneously and to speed up scanning of the entire field-of-view by up to 16 times without noticeable deterioration of the data quality. The wide-beam emission also enabled the implementation of multistatic operations, where ionospheric scatter signals from one radar are received by other radars with overlapping viewing areas. These novel operations required the development of a new model to determine the geographic location of the source of the multistatic radar echoes. Our preliminary studies showed that, in comparison with the conventional monostatic operations, the multistatic operations provide a significant increase in geographic coverage, in some cases nearly doubling it. The multistatic data also provide additional velocity vector components, increasing the likelihood of reconstructing full plasma drift velocity vectors. The developed operational modes can be readily implemented at other fully digital SuperDARN radars.