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

该项目将重点研究从极地和极光e区等离子体波观测到的大部分未开发的相干回波，这些回波是由2010年初部署在麦克默多的第一个美国南极高频电离层雷达观测到的，该雷达与SuperDARN国际项目中的其他南极和北半球高雷达一起使用。最近关于极光e区不规则性的工作，将superdma作为一个全球阵列进行了探索，已经清楚地证明了纵横角或磁倾角条件对e区雷达极光的发生和相速度的重要性。麦克默多雷达的初步观测显示大量的短程回波，其性质与极光e区回波非常相似，但在几何向角非常高的位置。该项目的研究将解决一个基本问题，即为什么麦克默多雷达能观测到来自极帽的e区回波。这些研究将包括进一步检查先前发现的具有不寻常特性的极光回波，例如，速度大大超过名义离子声速度并且与等离子体流动角无关。他们还将评估e区雷达极光的磁共轭程度，并建立e区不规则性与等离子体漂移速度之间的关系。这项研究将由一名新的年轻PI领导，并将有助于研究生的培训和教育。

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.