Relationship Between Sprite Current and Morphology
Relationship Between Sprite Current and Morphology
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DOI：
10.1029/2020ja028930
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发表时间：
2021-03-01
影响因子：
2.8
通讯作者：
Stenbaek-Nielsen, H.
中科院分区：
文献类型：
--
作者：
Contreras-Vidal, L.;Sonnenfeld, R. G.;Stenbaek-Nielsen, H.
2019年6月2日和3日，在新墨西哥州中部的朗缪尔实验室捕获了63只精灵。被调查的两个风暴位于得克萨斯州西北部，距离观测点400-800公里。光学记录是用Phantom V2010相机以每秒100,000帧的速度进行的。利用灵敏慢速天线(LEFA)实现了闪电和精灵电场的电磁遥感。来自地球网络全闪电网络(ENTLN)的数据被用来定位精灵母闪光。这三个数据集的综合信息显示，超过一半的精灵观测到的惊人比例具有明显的电磁特征，这些特征归因于在精灵体内流动的电流。此外，与之前的报告相比，这些精灵电流签名异常大。精灵的电场变化幅度约为母体闪电的一半，对应的精灵峰值电流平均为26-58kA。最大的精灵具有高达2700kA公里的电流矩，这是从一种求解麦克斯韦方程的计算高效方法推断出来的。精灵的电磁特征和高速光学记录的详细比较表明，包含向上流光的光学大精灵(胡萝卜和水母)往往比只显示向下流光发展的(柱状精灵)具有更大的电流。最后，随着形态复杂性的增加，峰值电流矩有明显的增加趋势，从柱状到胡萝卜再到水母精灵。
On June 2 and 3, 2019, 63 sprites were captured from Langmuir Laboratory in central New Mexico. The two storms investigated were located in northwest Texas, 400-800 km away from the observation site. Optical recordings were made with a Phantom V2010 camera operating at up to 100,000 frames per second. Electromagnetic remote sensing of lightning and sprite electric fields was performed with a sensitive slow antenna (LEFA). Data from the Earth Networks Total Lightning Network (ENTLN) were used to locate the sprite parent flashes. The combined information of these three data sets reveals that a staggering fraction of more than half of the sprites observed have a distinguishable electromagnetic signature attributed to currents flowing within the sprite body. Furthermore, these sprite current signatures were unusually large in comparison to previous reports. The sprite electric field changes have roughly half the amplitude of their parent lightning flash's, corresponding to sprite peak currents of 26-58 kA on average. The largest sprites have current moments of up to 2,700 kA km, as inferred from a computationally efficient method to solve Maxwell's equations. Detailed comparison between the sprites' electromagnetic signatures and high-speed optical recordings show that optically large sprites containing upward streamers (carrots and jellyfish) tend to have larger electrical currents than the ones displaying only downward streamer development (column sprites). Finally, a clear increasing trend in peak current moment is evident with increasing morphological complexity, from columns to carrots to jellyfish sprites.