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

点击翻译按钮获取中文摘要

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.