Theoretical Study of Ground-Based Auroral Radio Emissions

该项目的目标是解决与在极光区地面观测到的从5千赫到5兆赫的无线电波有关的几个关键理论问题，这些无线电波称为极光咆哮。在NSF先前的支持下，PI和他的同事们能够为两种类型的排放提供基本的解释--连续的咆哮是在F区源附近的密度耗尽内产生的，而离散的咆哮是密度增强的本征模。这两种发射的一个共同的关键因素是产生上混合波，即Z模波，并将其转换为电磁波。以前的研究项目主要关注上混合波/Z模波的产生过程的表征和理解。拟议研究的重点将是Z模波到电磁波的转换和/或耦合。这样的研究对于将连续和离散轰鸣排放理论建立在完全可行的基础上是至关重要的。

The objective of the project is to address several key theoretical issues relevant to the frequency-range from 5kHz to 5MHz radio waves observed on the ground in the auroral zone, known as auroral roars. With the previous support from NSF, the PI and his colleagues were able to provide basic explanations for two types of emissions - the continuum roars are generated within the density depletion near the F -region source, while the discrete roars are eigenmodes of density enhancements. A key ingredient common to both types of emissions are the generation of upper-hybrid, or Z -mode waves, and their conversion to electromagnetic waves. The previous research project was largely concerned with the characterization and understanding of the generation process of upper-hybrid/Z -mode waves. The focus of the proposed research will be on the conversion and/or coupling of Z -mode waves to electromagnetic waves. Such a study is essential to put the theories of continuum and discrete roar emissions on a fully viable footing.