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.
