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

我的研究兴趣是解释地球电离层中的自然现象。电离层是下面的中性大气和上面的完全电离的空间环境之间的部分电离的过渡区。电离介质或等离子体介质通常被称为物质的第四态，因为它是一些电子离开(或附着)形成带电介质的中性原子或分子的状态。这种电离介质的组成和动力学受电场和磁场的支配，因此表现出与我们熟悉的地球表面中性大气显著不同的行为。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该介质；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，我使用这些无线电技术，包括地面和卫星，来测量电离层的组成和动态。在我的科学领导下，我和我的研究生们推进了对这种电离介质的运动和组成的理解。我们不仅发现了由于电离介质本身的原因，电离介质漂移速度测量的不准确，而且我们提出了许多方法来纠正它。这一校正过程还以高空间和时间分辨率提供了关于电离层中带电粒子密度的补充信息。这一资助期的大部分时间将涉及验证和改进这些技术，并向整个空间物理界推广这些技术，但有一种技术已被证明是非常有用的，它已被作为标准雷达操作模式加以实施。另一个主要研究方向是模拟无线电波在电离层中的传播。这些研究目标是通过考虑无线电波在这种电离介质中传播时如何被修改来绘制电离层中的大尺度结构图。这项工作是由一项将无线电信号从地面传输到卫星上的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.