Solar flares, energetic particles, and Earth‐impacting coronal mass ejections enhance ionization in the lower ionosphere, inhibiting radio wave propagation in the Earth‐ionosphere waveguide (EIWG). This enhanced ionization is observed locally by ionosondes and GPS/GNSS receivers, but spatial coverage of these observations is limited by receiver location. Very low frequency (VLF) propagation studies have previously been performed to assess the impact of space weather on the EIWG; however, these studies are typically limited by small numbers of fixed VLF transmitters and receivers and observe only the region of the EIWG along propagation paths between transmitters and receivers. Here, we use global lightning as a VLF source and an existing lightning detection network as a receiver. By mapping sferic propagation paths between lightning strokes and numerous network stations and considering how this distribution of paths changes during solar events, we can identify attenuation regions in the EIWG caused by space weather. We describe the VLF response in the EIWG to two X‐class solar flares and compare mapped attenuation regions with those provided by the NOAA D‐Region Absorption Prediction model. The identified attenuation regions associated with these flares match the D‐Region Absorption Prediction‐predicted regions well in both spatial extent and onset timing. Measurements of VLF attenuation caused by solar flares can provide ground‐truth confirmation of modeled attenuation and can inform the detection efficiency of lightning location networks. This analysis also paves the way for real‐time VLF attenuation mapping in the EIWG.

中文翻译：

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使用全球闪电定位网络检测X级太阳耀斑引起的地球电离层波导中的VLF衰减

太阳耀斑，高能粒子和影响地球的日冕物质抛射增强了下部电离层的电离作用，从而抑制了电波在地球电离层波导（EIWG）中的传播。电离超声探空仪和GPS / GNSS接收器可以局部观测到这种增强的电离，但是这些观测的空间覆盖范围受到接收器位置的限制。先前已经进行了甚低频（VLF）传播研究，以评估太空天气对EIWG的影响；但是，这些研究通常受到少量固定VLF发射器和接收器的限制，并且仅沿发射器和接收器之间的传播路径观察EIWG区域。在这里，我们使用全局闪电作为VLF源，并使用现有的闪电检测网络作为接收器。通过绘制雷击和许多网络站点之间的特定传播路径，并考虑在太阳事件期间路径的这种分布如何变化，我们可以确定由空间天气引起的EIWG中的衰减区域。我们描述了EIWG中对两个X级太阳耀斑的VLF响应，并将映射的衰减区域与NOAA D区域吸收预测模型提供的衰减区域进行了比较。识别出的与这些耀斑相关的衰减区域在空间范围和开始时间上都与D区域吸收预测预测的区域非常匹配。由太阳耀斑引起的甚低频衰减的测量可以为模型衰减提供实实在在的确认，并且可以告知闪电定位网络的检测效率。该分析还为EIWG中的实时VLF衰减映射铺平了道路。