On the Terrestrial Gamma‐Ray Flashes Preceding Narrow Bipolar Events
On the Terrestrial Gamma‐Ray Flashes Preceding Narrow Bipolar Events
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DOI：
10.1029/2020gl092160
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发表时间：
2021-04
影响因子：
5.2
通讯作者：
Hongbo Zhang;G. Lu;F. Lyu;S. Xiong;M. Ahmad;Q. Yi;Dongshuai Li;Tao Xian;Jing Yang;Feifan Liu;Baoyou Zhu;Y. Pu;S. Cummer;M. Briggs;X. Qie
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作者：
Hongbo Zhang;G. Lu;F. Lyu;S. Xiong;M. Ahmad;Q. Yi;Dongshuai Li;Tao Xian;Jing Yang;Feifan Liu;Baoyou Zhu;Y. Pu;S. Cummer;M. Briggs;X. Qie
狭义双极事件（NBEs）偶有报道发生在地球伽马射线闪光（TGFs）后的几毫秒内，但由于缺乏足够的观测，其形成机制仍然很神秘。在这里，报告了这种情况下的另外9个tgf，它们具有并发的LF信号和闪电位置数据。这些TGF中伽马射线的产生比NBEs的发生早至少60µs，持续时间为13.5 ms，在TGF发生前20 ms内未发现其他快速先导放电。在雷暴中，TGF -诱发的正北东电现象发生在8.6-11千米的高度，很可能发生在闪电起始的高电场（E - field）区域。分析表明，NBE -前置TGFs比EIP -前置TGFs具有更强的能谱和更大的高能光子比例。我们的发现支持了大尺度雷暴E场中伽马射线产生的相对论反馈机制。
Narrow bipolar events (NBEs) are occasionally reported to occur within a few ms after Terrestrial Gamma‐ray Flashes (TGFs), while the formation mechanism remains mysterious partially due to the lack of sufficient observations. Here, nine more TGFs of this scenario are reported with concurrent LF sferics and lightning location data. The gamma‐ray production in these TGFs preceded the occurrence of NBEs by a minimum of 60 µs up to 13.5 ms, and no other fast leader discharge was found within 20 ms before the TGF. The TGF‐preceded positive NBEs occurred at altitudes of 8.6–11 km in thunderstorms, likely in the high electric field (E‐field) region of lightning initiation. The analyses show that the NBE‐preceding TGFs bear harder energy spectrum with larger proportion of high‐energy photons than EIP‐related TGFs produced in association with lightning leader. Our findings support the relativistic feedback mechanism of gamma‐ray generation in the large‐scale thunderstorm E‐field.