Ionospheric Radio Science with ePOP at Auroral Latitudes

English Abstract:

The orbit of the Canadian small satellite CASSIOPE allows the Enhanced Polar Outflow Probe (ePOP) payload that it carries to directly observe ionospheric processes at a variety of altitudes and latitudes. The 325km x 1500km elliptical orbit at 81° inclination permits comparison of topside collisionless plasmas with denser plasmas below and of mid-latitude plasmas with polar-cap ones. In coordinated operations of the ePOP Radio Receiver Instrument (RRI) with measurements by the SuperDARN (SD) radars, the RRI has recorded HF signals originating at the Saskatoon and Rankin Inlet SDs. Here, the combination of both EM propagation directly incident from the radar emitters and of signals backscattered from nearby irregularities provides new insights into the nature of coherent backscatter. Transionospheric propagation through the F region modified by ionospheric heaters and detected by the RRI is used to image the structure therein, and to better understand electromagnetic propagation through irregular media. Spontaneous radio emissions at very low frequency and medium frequency borne of auroral-particle free-energy sources manifest a variety of spatial scales.