Sondrestrom Radar Observations of Plasma Processes on Polar Cusp and Discrete ARC Field Lines

建议利用格陵兰岛Sondre Stromfjord的非相干散射雷达设施进行实验，并研究与白天极光椭圆形和晚间部分离散弧线相连的磁力线上的等离子体过程。最近对雷达的升级使几种新的工作模式成为可能，这将使测量电离层属性，如垂直和水平离子漂移、电子密度以及离子和电子温度的时间和空间分辨率大大提高。将进行一项精心规划的实验计划，利用这些新能力以及来自其他地面仪器和卫星的额外数据。其目标是(1)研究日间极光椭圆形电离层属性的时空变化，(2)确定从日间椭圆形电离层输送到磁层的离子的来源区域，以及(3)开发在与极光弧相连的场线上观测高海拔等离子体属性的雷达方法。白天的观测将用来确定理论模拟上升离子通量的初始条件及其对近地等离子体片中磁层压力平衡的影响。极光场线上的高空测量将用于确定与极光加速区有关的等离子体湍流是否存在相干回波。这些实验的结果将为极光降水的地面研究建立一个坚实的观测框架，并将对我们理解白天的磁层/电离层耦合及其与极光亚风暴过程的关系具有重要意义。

Experiments are proposed using the incoherent scatter radar facility at Sondre Stromfjord, Greenland, and to study plasma processes on magnetic field lines connected to the dayside auroral oval and discrete arcs in the evening sector. Recent upgrades to the radar have made several new operating modes possible that will enable measurements of ionospheric properties such as vertical and horizontal ion drift, electron densities, and ion and electron temperatures with greatly improved temporal and spatial resolution. A carefully planned experimental program will be conducted that takes advantage of these new capabilities as well as additional data from other ground-based instruments and satellites. The objectives are (1) to study the spatial and temporal variations of ionospheric properties in the dayside auroral oval, (2) to characterize the source region for ions that are transported from the dayside oval to populate the magnetosphere, and (3) to develop radar methods for observing plasma properties at high altitudes on field lines connected to auroral arcs. The dayside observations will be used to define the initial conditions for theoretical modeling of upward ion fluxes and their effects on magnetospheric pressure balance in the near-Earth plasma sheet. The high altitude measurements on auroral field lines will be used to determine the presence of coherent echoes from plasma turbulence associated with the auroral acceleration region. The results of these experiments will establish a firm observational framework for ground-based studies of auroral precipitation and will have important implications for our understanding of magnetosphere/ionosphere coupling on the dayside and how it relates to auroral substorm processes.