Energetic Radiation from Lightning Leaders: Effects and Origins

闪电领导者的能量辐射：影响和起源

• 批准号: 1106779
• 负责人: Victor Pasko
• 金额: $ 40.47万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-15 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1106779&HistoricalAwards=false
• 关键词: Energetic; Radiation; Lightning; Leaders; Effects; Energetic; Radiation; Lightning; Leaders; Effects

Neither the exact mechanisms through which lighting is initially triggered and propagates through the free atmosphere nor the relationship of these processes to recently emerging observations of high-energy emissions associated with active thunderstorms are well understood. This research will apply state-of-the-art numerical simulation methods to investigate the emission of energetic electrons from lightning-related charge-streamer and stepped-leader discharges and the propagation of the associated energetic radiation (from X-rays to hard X-rays and terrestrial gamma-ray flashes) through the Earth's atmosphere. The only known mechanism capable of explaining generation of associated high-energy electrons is the "runaway process" by which energy gained from an imposed electric field exceeds that lost to collisions, thus accelerating electrons to very high energies (1 MeV). To-date, two scenarios for initially "seeding" this runaway breakdown process have been proposed: (1) cosmic rays, and (2) "thermal" runaway induced by extremely high electric fields. Theoretical and experimental studies have shown the paramount importance of the coupling of streamer and leader discharge dynamics to the thermal runaway process, which is in-turn now thought to be inseparable from emission of X-rays by lightning or production of terrestrial gamma-ray flashes. Targeted observations of high-energy radiative emissions by thunderstorms and associated electrical activity have recently been obtained from ground-based, airborne and satellite platforms, but the detailed nature of relationships among these previously uncorrelated phenomena have not previously been quantified as this project sets out to do.The Intellectual Merit of this activity is defined by efforts to develop a unifying theoretically-sound explanation for the location, timing and specific nature of observed high-energy radiation originating in the Earth's atmosphere. The importance of related questions is emphasized by the need to quantify the intensity of radiation emitted from lightning and to understand its relationship to the formation and propagation of lightning channels, and extends to the possibility of adverse health impacts for crewmembers and passengers of aircraft transiting regions of strong thunderstorm activity. Broader impacts of this effort will come through development of an interdisciplinary research program, via graduate and undergraduate student education and training, and through dissemination of results using illuminating graphical methods.

最初触发照明的确切机制，也没有通过自由大气传播，也没有这些过程与最近对与主动雷暴相关的高能排放的新出现的观察结果的关系。 这项研究将采用最先进的数值模拟方法来研究与雷电相关的电荷流和阶梯式领导者放电的能量电子的发射，以及相关的能量辐射的传播（从X射线到硬X射线到硬X射线到硬质量X射线和地面伽马射线闪光灯）。 唯一能够解释相关高能电子产生的已知机制是从施加的电场中获得的能量超过碰撞的“失控过程”，从而将电子加速到非常高的能量（1 MEV）。 迄今为止，已经提出了两个最初“播种”这个失控过程的方案：（1）宇宙射线和（2）由极高的电场引起的“热”失控。 理论和实验研究表明，流媒体和领导者放电动力学与热失控过程的耦合至关重要，现在被认为是通过闪电或陆地伽马射线闪光的产生X射线发射而持续不可分割的。 最近已经从地面，机载和卫星平台中获得了针对高能辐射排放和相关的电活动的有针对性观察，但是以前尚未量化这些项目的详细性质，因为这些项目的设置并没有被量化。观察到的高能辐射起源于地球大气层。 需要量化从闪电发出的辐射强度并了解其与闪电通道的形成和传播的关系，并扩展到对船员的不利影响和飞机乘客对强烈thundestrorm活动的飞机过境区域的不利影响。 这项工作的更广泛的影响将通过开发跨学科研究计划，通过研究生和本科生的教育和培训，以及使用照明图形方法传播结果。