Modelling troughs, blobs, and patches in the ionosphere for the HF SuperDARN-Radio Receiver Instrument experiment for the ePOP mission

The Cascade demonstrator Small-Sat and Ionospheric Polar Explorer (CASSIOPE) satellite is scheduled to be launched in 2012. On board this satellite will be a suite of eight scientific instruments comprising the enhanced Polar Outflow Probe (ePOP). One instrument is the Radio Receiver Instrument (RRI) which will be used to receive HF transmissions from ground transmitters such as the Super Dual Auroral Radar Network (SuperDARN) array. The SuperDARN-RRI transionospheric experiment will be used to detect and characterize ionospheric structures. The high latitude ionosphere contains various structures such as, troughs of depleted electron density and patches or blobs of enhanced electron density. These structures occur at various scale sizes from several hundred kilometers (large scale) to a few tens of kilometers or less (small-scale). The electron density enhancement or depletion in these structures can be more than an order of magnitude different from the background electron density. Modelling of the characteristics of the HF signal received at ePOP for various ionospheric electron density structures has been undertaken in preparation for the RRI-SuperDARN experiment. The effect of these ionospheric electron density blobs and troughs on signal parameters, such as Faraday rotation, wave polarization, signal delay time, and relative propagation mode power has been modelled. At HF frequencies, these parameters are sensitive to electron density structures in the ionosphere. In particular, analysis of the polarization of the received signal, which will change as the satellite orbits over a ground transmitter due to differential Faraday rotation, will allow detection of small-scale structures.