HF Backscatter from the Polar and Auroral E-Region Ionosphere: Origin, Conjugacy, and Electric Field Control

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The project will focus on investigations into the largely unexplored subset of coherent echo returns from the polar and auroral E-region plasma waves observed with the first U.S. Antarctic high-frequency ionospheric radar deployed at McMurdo in early 2010 in conjunction with other Antarctic and high northern hemisphere radars within the SuperDARN international program. Recent body of work on auroral E-region irregularities exploring SuperDARN as a global array has clearly demonstrated importance of the aspect angle or, equivalently, magnetic inclination angle conditions for both occurrence and phase velocity of E-region radar aurora. Initial observations by the McMurdo radar show abundance of short-range echoes with properties very similar to auroral E-region echoes but at locations with very high geometric aspect angles. The project's research will address a fundamental question of why E-region echoes from the polar cap are observed at all by the McMurdo radar. These investigations will include further examination of the previously found auroral echoes with unusual properties, e.g., velocities greatly exceeding nominal ion-acoustic speed and independent of the plasma flow angle. They will also evaluate the extent of magnetic conjugacy of the E-region radar aurora and establish the relationship between E-region irregularities and plasma drift velocities. This research will be led by a new young PI and will also contribute to the training and education of a graduate student.