Collaborative Research: Physics Based Modeling of Blue Jets

合作研究：基于物理的蓝色喷气机建模

• 批准号: 1226237
• 负责人: Gennady Milikh
• 金额: $ 16.31万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1226237&HistoricalAwards=false
• 关键词: Collaborative; Research; Physics; Based; Modeling

Narrow cones of blue light that propagate upward from the top of a thundercloud were discovered during the Sprites94 aircraft campaign. Two types of blue jets (BJ) have been observed. The brief upward jets, which propagate only a few km and terminate below 26 km, were dubbed blue starters (BS), while so-called gigantic blue jets (GBJ) propagate into the mesosphere/lower ionosphere. It is widely accepted that BJ?s are produced by an upward propagating leader from thunderstorms. Some attempts have been made to describe the leader formation, including recent model of bipolar BJ. However, despite substantial progress in the theoretical understanding of this complicated phenomenon, significant puzzles remain. In fact, two outstanding problems are still unresolved and both are relevant to the laboratory leaders, as well as to the leaders formed by lightning. Namely, which mechanism governs the low propagation velocity of the leader, and how a self-consistent electric field in the streamer zone of a leader is formed. This research will focus on quantitative modeling of Blue Jets/Blue Starters/Gigantic Blue Jets. It will combine two major models, the first is an analytical and numerical study of current contraction, which determines transformation of a streamer flash into a leader, and which governs slow propagation velocity of BJ?s. The second is a model of the average electric field formed by a group of streamers in the streamer zone of a leader, which determines the BJ formation. The theoretical study will be complemented by the table top experiments that could be used for validation of the existing models. The ground based and satellite-borne optical and ultraviolet observations will attempt to validate the model predictions. Understanding the physics of BJ/BS/GBJ is not only a frontier scientific topic, but it could provide a mechanism for direct transient coupling between the ionosphere and stratosphere with implication to the global electric circuit. Potential applications include: extending fundamental knowledge in the physics of gas discharge and weakly ionized plasma by applying our model to laboratory experiments of streamer and leader breakdown, and influencing the design of powerful lasers and plasma chemical reactors through a quantitative understanding of current contraction. The program will support the education and training of the University of Maryland students in this multidisciplinary field, combining aspects of theoretical and computational plasma physics as well as gas dynamics. The study will promote collaboration between the academia and industry. It also involves broad international collaboration between Princeton University, the University of Maryland, and leading scientists from the Russian Academy of Sciences.

Sprites94 飞机活动期间发现了从雷雨云顶部向上传播的狭窄蓝光锥体。已观察到两种类型的蓝色喷流（BJ）。 短暂的向上喷流仅传播几公里，终止于 26 公里以下，被称为蓝色起始喷流 (BS)，而所谓的巨大蓝色喷流 (GBJ) 传播到中间层/下电离层。人们普遍认为，BJ 是由雷暴中向上传播的先导产生的。人们已经做出了一些尝试来描述领导者的形成，包括最近的双极 BJ 模型。 然而，尽管对这一复杂现象的理论理解取得了实质性进展，但仍然存在重大谜团。事实上，有两个悬而未决的问题仍然没有解决，这两个问题都与实验室领导者有关，也与闪电形成的领导者有关。 即，哪种机制控制先导的低传播速度，以及如何在先导的流注区中形成自洽电场。 这项研究将重点关注蓝色喷气机/蓝色起动机/巨型蓝色喷气机的定量建模。它将结合两个主要模型，第一个是电流收缩的分析和数值研究，它决定流光闪光到领导者的转变，并控制 BJ 的缓慢传播速度。第二个是先导流带区中一组流带形成的平均电场模型，它决定了 BJ 编队。理论研究将得到桌面实验的补充，可用于验证现有模型。地面和星载光学和紫外线观测将尝试验证模型预测。了解 BJ/BS/GBJ 的物理原理不仅是一个前沿科学课题，而且可以提供电离层和平流层之间直接瞬态耦合的机制，对全球电路产生影响。 潜在的应用包括：通过将我们的模型应用于流注和先导击穿的实验室实验，扩展气体放电和弱电离等离子体的物理基础知识，并通过对电流收缩的定量理解影响强大的激光器和等离子体化学反应器的设计。该计划将支持马里兰大学学生在这个多学科领域的教育和培训，结合理论和计算等离子体物理以及气体动力学的各个方面。该研究将促进学术界和工业界之间的合作。它还涉及普林斯顿大学、马里兰大学和俄罗斯科学院领先科学家之间的广泛国际合作。