CEDAR: Natural and Rocket-Triggered Lightning in the Mesosphere-Lower Thermosphere-Ionosphere (MLTI) System

该研究项目将定量研究自然闪电和火箭触发闪电对海拔 60 至 100 公里之间大气层中层-低层热层-电离层 (MLTI) 区域的影响。 实验工作将集中于关于自然闪电产生的发光现象（统称为瞬态发光事件（TLE））的几个突出问题，并将研究火箭触发闪电作为这些干扰源的可能作用。 主要的理论工作将结合最先进的数值模型来预测中间层/电离层对与观测结果一致的实际回程电流的反应。 实验工作的重点是在佛罗里达州布兰丁营国际闪电研究和测试中心 (ICLRT) 及其附近观测到的闪电。 该项目将提供对致病闪电波形（自然和火箭触发）的同时宽带（1 Hz-20 MHz）观测、用于瞬态发光事件光学检测的光度观测，以及对 D 区电离层电导率变化敏感的极低频（VLF，3-30 kHz）信号的窄带（200 Hz 带宽）观测。 这些系统将在整个资助期间持续监测与自然闪电相关的电离层事件。 将在夜间强烈雷暴期间尝试使用经典的火箭和电线技术来触发闪电。 该计划将解决以下问题： 1) 成功产生 TLE 的闪电的宽带 (1 Hz-20 MHz) 特性是什么？ 2) 成功产生散射甚低频信号的电离层电导率变化的闪电宽带特性是什么？ 3) TLE 的哪些特征与观察到的 VLF 散射最密切相关？

The research project will quantitatively investigate the effects of both natural and rocket-triggered lightning in the mesosphere-lower thermosphere-ionosphere (MLTI) region of the atmosphere between 60 and 100 km altitude. The experimental effort will focus on several outstanding questions regarding the production of light-emitting phenomena known collectively as transient luminous events (TLEs) by natural lightning and will investigate the possible role of rocket-triggered lightning as a source for these disturbances. The primary theoretical effort will combine state-of-the-art numerical models to predict the mesospheric/ionospheric reaction to realistic return-stroke currents consistent with observations. The experimental effort centers on lightning observed at and near the International Center for Lightning Research and Testing (ICLRT) in Camp Blanding, Florida. The project will provide simultaneous wideband (1 Hz-20 MHz) observations of the causative lightning waveforms (both natural and rocket-triggered), photometric observations for the optical detection of transient luminous events, and narrowband (200-Hz bandwidth) observations of very low frequency (VLF, 3-30 kHz) signals that are sensitive to conductivity changes in the D-region ionosphere. These systems will provide continuous monitoring of ionospheric events related to natural lightning throughout the three-year period of the award. Attempts to trigger lightning using the classical rocket-and-wire technique will be performed during intense nighttime thunderstorms. This program will address the following questions: 1) What are the wideband (1 Hz-20 MHz) characteristics of lightning that successfully produce TLEs? 2) What are the wideband characteristics of lightning that successfully produce ionospheric conductivity changes that scatter VLF signals? 3) What characteristics of TLEs are most closely associated with the observed VLF scattering?