Simulations and Theory of Streamer Discharges in Transient Luminous Events

瞬态发光事件中流光放电的模拟和理论

• 批准号: 1623780
• 负责人: Victor Pasko
• 金额: $ 36.13万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2020-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1623780&HistoricalAwards=false
• 关键词: Simulations; Theory; Streamer; Discharges; Transient

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.

瞬变发光事件（TLEs）是发生在地球平流层、中间层和低热层的大尺度光学事件，与雷暴中的电活动直接相关。热释电脉冲耦合对流层到电离层，并可能导致加热，加速和光电离在较低的热层。TLE是一种结构丰富的现象，其基本元素是被称为流光的非导电等离子体。TLE研究是理解流光放电微观物理的关键，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发展，因此拖缆启动的许多方面还没有得到很好的理解。拟议的工作包括理论研究，将缩小几个知识差距。该提案还将有助于本科生和研究生的教育和培训。提案者将在现有模型的基础上，将小尺度现象（精灵流光引发）嵌入更大的领域，并添加额外的化学物质。 具体而言，PI将调查：1.等离子体不均匀性在子画面流光启动中的作用; 2.在分层空气密度内长距离（~10 km）传播拖缆;以及3.精灵对低电离层化学的影响。这些研究将为拖缆的工业应用（包括臭氧生产和污染控制）和与TLE有关的电离层修改提供信息。