Observations and Modeling of the High Latitude Ionosphere

该项目的第一部分将研究与在极高纬度高层大气中形成薄金属离子结构有关的物理和化学过程。实验将在格陵兰岛Sondrestrom的非相干散射雷达设施中进行。PI将使用常规测量程序(目前正在进行中)来建立一个数据库，该数据库描述不同的结构，如单层和双层、纬度和海拔分布。他还将使用一种新的实验模式，同时确定电场的纬度变化和高分辨率的密度结构。结合一个新的数值模式，这些数据将调查电场和中性风在层形成中的相对作用，确定时变电场的影响，并发现空气动力学参数的影响，如离子-中性碰撞频率。其次，PI将进一步发展一个新的极地电离层欧拉三维时变模型。与传统的拉格朗日方法相比，这种方法具有更高的空间分辨率，从而可以对极性等离子体结构进行随时间变化的研究，并能更好地与数据进行比较。利用一个新的电场模型，PI将研究与时间相关的电离层效应，特别是在向北的行星际磁场(IMF)条件下。该模型可以确定电离层对时变IMF的连续响应。如果模型有合适的IMF和空间粒子数据输入，他就可以预测“太空天气”的影响。

The first part of this project will be studying the physical and chemical processes associated with formation of thin metallic-ion structures in the very-high-latitude upper atmosphere. Experiments will be conducted at the incoherent-scatter radar facility at Sondrestrom, Greenland. The PI will use a routine measurement program (currently underway) to establish a database that characterizes different structures, such as single versus double layers, latitudinal and altitude distributions. He will also use a new experimental mode that simultaneously determines latitudinal variation of electric fields and high resolution density structures. In conjunction with a new numerical model, these data will investigate the relative roles of electric fields and neutral winds in layer formation, determine the effects of time-varying E-fields, and discover the effects of aeronomic parameters, such as the ion-neutral collision frequency. Secondly, the PI will further develop a new Eulerian 3-D time-dependent model of the polar ionosphere. This approach is advantageous to the traditional Lagrangian method in permitting efficient high spatial resolution, in turn allowing time-dependent studies of polar plasma structures and better comparisons with data. Using a new electric field model, the PI will investigate time-dependent ionospheric effects, particularly for northward interplanetary magnetic field (IMF) conditions. This model can determine the continuous ionospheric response to a time-varying IMF. He can then predict "space weather" effects, if appropriate IMF and space-particle data inputs are available to the model.