Collaborative Research: Physics Based Modeling of Blue Jets

该奖项是根据2009年《美国复苏和再投资法案》(公法111-5)资助的。该项目将专注于进一步发展一种被称为蓝色喷气机、蓝色启动器和巨大蓝色喷气机的高层大气现象模型。蓝色喷流是一种狭窄的蓝光锥体，从雷云顶部向上传播，在一次飞机行动中被发现。在活动期间还发现了被称为蓝色启动器(BS)的仅传播几公里并在26公里以下终止的短暂向上急流，以及传播到中间层和低电离层的巨大蓝色急流(GBJ)。此外，俄罗斯学生微型卫星Tatiana上的紫外线传感器还探测到了300-400 nm光谱范围内的强烈闪光。它们的持续时间和辐射能量与蓝色喷流产生的辐射能量相同。这些闪电和GBJ一样，都位于闪电率较低的海洋和海岸上，这表明紫外线闪电可能与GBJ有关。尽管在对这一复杂现象的理论理解上取得了实质性进展，但仍然存在重大困惑。这个项目将开发一个基于第一原理的模型，不同于现有的包含一些任意参数的模型。该模型将采用分析和计算相结合的方法进行开发。模型的预测将通过地面和星载探测器获得的光学、紫外线和极低频率(ELF)数据进行验证。了解这些特征的物理特性可以阐明电离层和平流层之间直接瞬时耦合的机制，并对全球电路产生影响。该活动的更广泛影响包括将该模型应用于拖缆和引线击穿的实验室实验，这反过来又对材料加工非常重要。该计划将支持马里兰大学研究生和本科生的教育和培训；它还涉及与俄罗斯和台湾科学家的广泛国际合作。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This project will focus on further development of a model of upper atmospheric phenomena known as Blue Jets, Blue Starters, and Gigantic Blue Jets. Blue Jets are narrow cones of blue light that propagate upward from the top of a thundercloud and were discovered during an aircraft campaign. Also discovered during the campaigns were short-lived upward jets which propagate only a few km and terminate below 26 km, dubbed blue starters (BS), as well as gigantic blue jets (GBJ) which propagate into the mesosphere and lower ionosphere. In addition, intense flashes in the spectral range 300-400 nm were detected by an ultra-violet (UV) sensor on board the Russian student microsatellite 'Tatiana'. Their duration and radiated energy are in the same range as those generated by blue jets. These flashes, like the GBJ, were located over oceans and shores where the rate of lightning flashes is low, which suggests that the ultraviolet flashes may be associated with the GBJ. Despite substantial progress in the theoretical understanding of this complex phenomenon, significant puzzles remain. This project will develop a model based on first principles, unlike existing models which include some arbitrary parameters. The model will be developed by using a combined analytical and computational approach. The predictions of the model will be validated by the optical, UV, and ELF (Extremely Low Frequency) data obtained by the ground based and satellite-borne detectors. Understanding the physics of these features could provide elucidation of a mechanism for direct transient coupling between the ionosphere and stratosphere with implication to the global electric circuit. The broader impact of the activity includes application of the model to laboratory experiments of streamer and leader breakdown, which in turn are important for material processing. This program will support the education and training at graduate and undergraduate students at the University of Maryland; it also involves a broad international collaboration with scientists from Russia and Taiwan.