Simulations and Theory of Streamer Discharges in Transient Luminous Events

瞬变发光事件（TLEs）是发生在地球平流层、中间层和低层热层的大尺度光学事件，与潜在雷暴中的电活动直接相关。TLEs脉冲耦合对流层和电离层，并可能在低层热层中导致加热、加速和光电离。TLEs是结构丰富的现象，其基本元素是被称为流光的丝状等离子体。TLE研究对于理解流光放电的微物理学至关重要，也是地球大气化学研究的一个重要领域。目前，对拖缆的现场观测超过了理论的发展，因此对拖缆起始的许多方面还没有很好的理解。建议的工作包括理论调查，将关闭几个知识空白。这项建议也将有助于教育和培训本科生和研究生。提议者将在现有模型的基础上，在更大的域中嵌入小规模现象（精灵流起始），并添加额外的化学物质。具体来说，PI将调查：1。等离子体不均匀性在雪碧飘带起始中的作用2. 在分层空气密度范围内，飘带长距离（~10公里）的传播；和3。精灵对低层电离层化学的影响。这些研究将为飘带的工业应用（包括臭氧生产和污染控制）和与tle有关的电离层改造提供信息。

Transient luminous events (TLEs) are large-scale optical events occurring in Earth's stratosphere, mesosphere and lower thermosphere that are directly related to electrical activity in underlying thunderstorms. TLEs impulsively couple the troposphere to the ionosphere and may result in heating, acceleration, and photoionization in the lower thermosphere. TLEs are richly structured phenomena, whose fundamental elements are filamentary plasmas called streamers. TLE studies are critical for understanding the microphysics of streamer discharges, and also represent an important area in the research of the chemistry in the Earth's atmosphere. Field observations of streamers currently outpace theoretical developments, and consequently many aspects of streamer initiation are not well understood. The proposed work consists of theoretical investigations that will close several knowledge gaps. This proposal will also contribute to the education and training of undergraduate and graduate students.The proposers will build upon an existing model by embedding small-scale phenomena (sprite streamer initiation) within a larger domain, and adding additional chemistry. Specifically the PI will investigate: 1. the role of plasma inhomogeneities in sprite streamer initiation; 2. propagation of streamers over long distances (~10 km) within stratified air density; and 3. the effects of sprites on lower ionospheric chemistry. These studies will inform industrial applications of streamers (including ozone production and pollution control) and TLE-related ionospheric modification.