Novel Remote Measurements and Analysis of Continuing Lightning Current

这笔赠款使设备的安装和操作在杜克大学测量超低频（超低频）磁场与某些闪电放电。 闪电过后，在留下的导电通道中，有时会有强大而持久的电流流过。 被称为持续电流，它不是很好地理解，但它是闪电物理学的一个细节，被认为与云带电和高层大气中的现象有关，如精灵和精灵。 持续的电流在ULF磁场中产生信号，可以在距离闪电源2000公里的地方检测到。 本项目将开发远程检测持续电流并从超低频测量结果推断其持续时间和波形的方法。 将通过比较佛罗里达布兰丁营野外观测站与触发闪电相关的持续电流的测量波形与从ULF测量推断的波形，验证数据解释。 目标是连续记录杜克ULF站可检测到的闪电放电产生的磁场，并将测量结果与风暴结构和气象条件联系起来。 如果持续的电流被证明与风暴的严重程度或演变阶段有关，它可能是研究和预测风暴的有用工具。

This grant enables the installation and operation of equipment at Duke University for measuring the ULF (ultra low frequency) magnetic field associated with certain lightning discharges. A strong and long-lasting current sometimes flows after lightning strokes in the conducting channel they leave behind. Called the continuing current, it is not well understood but is a detail of the physics of lightning that is thought to be related to cloud electrification and to phenomena in the high atmosphere such as sprites and elves. Continuing currents produce signals in the ULF magnetic field that can be detected as far as 2000 km from the lightning source. Methods will be developed on this project to detect continuing currents remotely and infer their duration and waveform from ULF measurements. The data interpretation will be validated by comparing measured waveforms of the continuing currents associated with triggered lightning at a field station in Camp Blanding, Florida, with the waveforms inferred from ULF measurements. A goal is to continuously record the magnetic fields from lightning discharges detectable at the Duke ULF station and relate the measurements to storm structure and meteorological conditions. If the continuing current turns out to be related to storm severity or stage of evolution, it may be a useful tool for the study and forecasting of storms.