GEM: Self-Consistent Model for Regions of Downward Auroral Current

磁层和电离层之间的主要耦合是通过沿地球磁场流动的电流完成的。向上的电流区通常是由许多卫星观测到的向下流动的电子造成的。相比之下，向下的电流区通常涉及向上流动的电子，而这些电子更难观察到。因此，我们对下行流区的突出表现落后于我们对上行流区的理解。这项研究将开发一张自洽的极光向下流区的等离子体和场特性的图像。这些结果将有助于更好地理解离子圆锥粒子分布、下指向电场和ELF/VLF湍流等特征。这项研究的理论基础将是将问题分解为两个独立但相互关联的问题，时间尺度截然不同。ELF/VLF湍流在毫秒的时间尺度上运行，而大尺度极光电流结构的演变在几分钟到几小时的时间尺度上发生。因此，可以在缓慢演变的背景分布的背景下确定自洽的高频频谱。

The primary coupling between the magnetosphere and the ionosphere is accomplished via electric currents flowing along the Earth's magnetic field. Upward current regions generally result from downward flowing electrons which have been observed with many satellites. In contrast, downward current regions generally involve upward flowing electrons that have been more difficult to observe. Thus our outstanding of the downward current regions has lagged behind our understanding of the upward current regions. This study will develop a self-consistent picture of the plasma and field properties of downward auroral current regions. The results will lead to a better understanding of such features as ion conic particle distributions, downward pointing electric fields and ELF/VLF turbulence. The theoretical underpinning of the study will be to break the problem into two separate but coupled problems with vastly different time scales. ELF/VLF turbulence operates on times scales of milliseconds, while the evolution of the large-scale auroral current structures takes place on time scales of minutes to hours. Thus a self-consistent high frequency spectrum can be determined in the context of a slowly evolving background distribution.