High time resolution mapping of polar ionospheric flows with the SuperDARN Borealis systems

Over the last few years, the five SuperDARN HF ionospheric radars operated by the University of Saskatchewan have been upgraded to digital systems that utilise the flexibility and reliability of software defined radios (SDRs). SDRs allow for a vastly greater control of radar transmit and receive operations, bringing with them new capabilities for scientific experiments that were previously not feasible on analogue hardware. This next generation of SuperDARN radar is named Borealis.    One new radar operating mode implemented at the Borealis radars has been full field-of-view imaging. On traditional SuperDARN radars, one full scan of an entire field-of-view (an area encompassing thousands of kilometres at F-region ionospheric altitudes) takes approximately 1 minute as each of the 16 beam directions is sequentially integrated over. With Borealis, every beam direction can be probed (or “imaged”) simultaneously, providing a 16-fold improvement in scan temporal resolution to 3.5 seconds.   We present a new ionospheric data product derived from Borealis imaging mode data: high time resolution mapping of polar E x B drifts. In contrast to traditional SuperDARN ionospheric convection patterns which are nominally derived every two minutes on a coarse global grid, Borealis convection patterns are derived locally over the Canadian polar cap every few seconds. This not only provides the opportunity to study mesoscale ionospheric phenomena like polar cap patches, flow channels, and substorms, but also allows for doing so at a temporal resolution not previously possible without compromising spatial coverage.