Title:  Bistatic SuperDARN Measurements: First-results

Abstract: The international network of scientific HF Doppler radars known as the Super Dual Auroral Radar Network (SuperDARN) operate in a coordinated but largely independent manner. Each radar operates primarily in a monostatic mode whereby radio waves transmitted from a given radar refract in the ionosphere and scatter back to the radar from either ionospheric density irregularities or from the Earth's surface. The resulting Doppler information is used in numerous studies of the thermosphere-ionosphere-magnetosphere system, including measurements of the large-scale plasma convection pattern. In a research project funded by the Air Force Research Laboratory we show the first bistatic measurements made by two independent SuperDARN radars located in Oregon and Kansas. Initial experiments indicate a persistent direct skywave path exists between the sites for frequencies between 10-16 MHz with the observed signal strength modulated by beam direction, time of day and frequency. In addition, a true bistatic mode is observed in which radio waves transmitted from one radar scatter from either the Earth/Ocean surface or from ionospheric density irregularities and travel to the other radar where they are received. Success of these initial experiments highlights the promise of developing additional ionospheric monitoring capabilities using SuperDARN.