CEDAR/GEM Postdoc: Fully Electrodynamic 3D Time-Domain Model of Lightning-Ionosphere Interactions

研究人员将开发一个完整的三维时域模型的闪电电离层相互作用，包括非线性效应和传播到磁层。该模型将能够准确测量闪电对低电离层（70-110公里）的影响，包括电子密度的耗尽和增强，以及通过电离层传输到磁层的部分能量的估计。 模型计算可以根据背景电离层密度、闪电峰值电流和持续时间、一天中的时间和闪电类型（云对地与云中）等参数进行校准。利用这些信息，可以从现有的卫星和地面全球闪电数据中估计闪电造成的密度增加。分析模型和实验数据的比较也将进行。 几十年来，闪电能量与电离层和磁层的耦合一直是一个未解决的问题。该研究将通过与全球闪电分布统计数据进行比较，在每次雷击和全球范围内量化静电和电磁能量的耦合过程。模型结果将提供电离层和磁层闪电能量的校准，作为闪电峰值电流、持续时间、地理位置、一天中的时间和电离层条件的函数。该研究将有助于理解低层大气和D区电离层之间由于闪电引起的能量耦合，以及能量耦合到内磁层。闪电产生的哨声波是辐射带高能粒子以闪电诱发电子沉淀事件形式沉淀的原因，该模型将有助于支持即将进行的欧洲空间局（ASIM）和塔拉尼斯（法国国家空间研究中心）卫星任务，这两颗卫星将从2012年开始监测全球的TLE活动。该模型将分发给感兴趣的用户，并将随时在一台合理的台式计算机上运行;因此，研究热释电的科学家可以确定与其光学观测有关的电场强度和电离层扰动。同样的比较也可以通过对瞬变发光事件的地面观测来实现。

The investigators will develop a full 3-dimensional time-domain model of the lightning-ionosphere interaction, including nonlinear effects and propagation into the magnetosphere. The model will enable accurate measurements of the effects of lightning on the lower ionosphere (70-110 km), in terms of electron density depletions and enhancements, as well as estimates of the fractional energy transmitted through the ionosphere into the magnetosphere. The model calculations can be calibrated against parameters such as the background ionospheric density, lightning peak current and duration, time of day, and type of lightning (cloud-to-ground versus in-cloud). Using this information, a global estimate of the density enhancement due to lightning can be made from existing satellite and ground-based worldwide lightning data. Comparison with analytical models and experimental data will also be made. The coupling of lightning energy to the ionosphere and magnetosphere has remained an unsolved problem for decades. The study will quantify the coupling process through both electrostatic and electromagnetic energy, both on a per-stroke basis and on a global basis, through comparison with worldwide lightning distribution statistics. The model results will provide calibration of lightning energy to the ionosphere and magnetosphere as a function of lightning peak current, duration, geographic location, time of day, and ionospheric conditions. This study will contribute greatly to understanding of the energy coupling between the lower atmosphere and the D-region ionosphere due to lightning, as well as coupling of energy into the inner magnetosphere. Lightning-generated whistler-mode waves are responsible for precipitation of energetic particles from the radiation belts, in the form of Lightning-induced Electron Precipitation (LEP) events.The model will be instrumental in support of the upcoming ASIM (European Space Agency) and TARANIS (CNES, France) satellite missions, which will monitor TLE activity globally beginning in 2012. The model will be disseminated to interested users and will readily run on a reasonable desktop computer; as such, scientists studying TLEs can determine the electric field intensities and ionospheric disturbances associated with their optical observations. The same comparisons will be enabled with ground-based observations of Transient Luminous Events.