Structure and physics of coherent radar scatter in the F-region terrestrial ionosphere

我的研究兴趣包括解释地球电离层的自然现象。电离层是介于下面的中性大气和上面完全电离的空间环境之间的部分电离过渡区。电离介质或等离子体介质通常被称为物质的第四种状态，因为它是一些电子离开（或附着）到中性原子或分子上形成带电介质的状态。这种电离介质的组成和动力学是由电场和磁场主导的，因此表现出与我们在地球表面熟悉的中性大气明显不同的行为。由于电离层开始于大约100公里的高度，只有火箭或卫星才能直接观测到这种介质；然而，远程探测该区域的一种方法是使用无线电和雷达技术。作为一名实验研究人员，我使用这些地面和卫星无线电技术来测量电离层的组成和动力学。在我的科学领导下，我和我的研究生们对这种电离介质的运动和组成有了更深入的了解。我们不仅发现了电离介质漂移速度测量的不准确性，而且我们提出了许多方法来纠正它。这一校正过程还提供了电离层中带电粒子密度的额外信息，并具有较高的时空分辨率。这一资助期的大部分时间将涉及验证和改进这些技术，以及向空间物理学界推广这些技术，但有一项技术已被证明非常有用，已被作为标准雷达操作模式实施。另一个主要的研究方向是模拟无线电波通过电离层的传播。这些研究目标是通过考虑无线电波在通过这种电离介质传播时如何被修改来绘制电离层中的大规模结构。这项工作是由一项将无线电信号从地面传输到卫星接收器的实验开始的。这颗卫星将于2013年发射。

My research interest involves explaining the natural phenomena in the terrestrial ionosphere. The ionosphere is the partially ionoised transition region between the neutral atmosphere below and the fully ionoised space environment above. An ionoised medium, or plasma medium, is often called the fourth state of matter as it is the state where some electrons leave (or attach) to neutral atoms or molecules forming an electrically charged medium. The composition and dynamics of this ionoised medium is dominated by electric and magnetic fields and therefore exhibits significantly different behaviour than the neutral atmosphere we are familiar with on the Earth's surface. As the ionosphere begins at roughly 100 km altitude only rockets or satellites can directly observe the medium; however, one method to remotely probe this region is by using radio and radar techniques. As an experimentalist researcher, I use these radio techniques, both ground and satellite based, to measure the composition and dynamics of the ionosphere. Under my scientific leadership, my graduate students and I have advanced the understanding of the motion and composition of this ionoised medium. Not only did we identify an inaccuracy in drift velocity measurements of the ionoised medium due to the medium itself, but we came up with a number of methods to correct for it. This correction process also supplied additional information on the charged particle density in the ionosphere and at a high spatial and temporal resolution. Much of this funding period will involve validating and improving these techniques, as well as promoting them to the space physics community at large, but one technique has proven so useful that it has been implemented as a standard radar operation mode. The other main research direction has been modelling the propagation of radio waves through the ionosphere. These research goals are to map large-scale structures in the ionosphere by considering how radio waves are modified while propagating through such an ionoised medium. This work was initiated by an experiment which is to transmit radio signals from the ground to a receiver on a satellite. The satellite is to be launched in 2013.