Collaborative Research: Physics Based Modeling of Blue Jets

在精灵94飞机的活动中发现了从雷暴云顶部向上传播的蓝色光锥。两种类型的蓝色喷流（BJ）已被观察到。 短暂的向上喷流，传播只有几公里，终止于26公里以下，被称为蓝色启动器（BS），而所谓的巨大蓝色喷流（GBJ）传播到中间层/低电离层。人们普遍认为，BJ？S是由雷暴的向上传播先导产生的。一些尝试已经被用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，但仍然存在重大难题。事实上，有两个突出的问题仍然没有解决，这两个问题都与实验室领导有关，也与闪电形成的领导有关。 也就是说，哪种机制控制的低传播速度的领导者，以及如何形成的自洽电场的流光区的领导者。 这项研究将集中在定量建模的蓝色喷气机/蓝色启动器/巨型蓝色喷气机。它将结合联合收割机两个主要模型，第一个是分析和数值研究电流收缩，这决定了转化成一个领导者的流光闪光，并管理缓慢的传播速度BJ？S.第二个是一个模型的平均电场形成的一组流光在流光区的领导者，它决定了BJ形成。理论研究将通过桌面实验进行补充，这些实验可用于验证现有模型。地面和星载光学和紫外观测将试图验证模式的预测。理解BJ/BS/GBJ的物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，并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光和先导击穿的实验室实验，扩展了气体放电和弱电离等离子体物理学的基础知识，并通过对电流收缩的定量理解影响了强大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州大学学生在这一多学科领域的教育和培训，结合理论和计算等离子体物理学以及气体动力学方面。这项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、马里兰州大学和俄罗斯科学院的主要科学家之间的广泛国际合作。

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.