Sprites in low‐frequency radio noise
Sprites in low‐frequency radio noise
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低频无线电噪声中的精灵
DOI：
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
T. Farges
中科院分区：
文献类型：
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作者：
M. Füllekrug;A. Mezentsev;S. Soula;O. V. D. Velde;T. Farges
低频无线电噪声是电磁背景辐射，在这里与用低光摄像机记录的39个精灵的亮度进行比较。研究发现，子画面亮度与电磁背景辐射的10-30 ms长的突然增强相一致，该背景辐射为16 -8 μV m−1Hz−1/2（16 -9 dB），在125 kHz附近具有相对最大值，这是用宽带（121 -400 kHz）数字无线电接收器测量的。这些子画面分为10组，每组2-5个连续的子画面，它们被电磁背景辐射的缓慢变化的增强信号所包围，最长可达2.1 s，增强信号为2.4 -5 μV m−1Hz−1/2（2.2 -4 dB）。观察到的电场强度为来自与Qin等人[2012 a]预测的指数增长和分支精灵流光相关的电子倍增的低频辐射设定了上限。这一上限对应于雷暴云上方140公里高度处的最大300-5000个精灵飘带。观测到的电磁背景辐射的一部分可能是由雷暴云内大量水平闪电和/或阶梯形先导闪电的快速连续产生的低频辐射叠加造成的，这将构成雷暴云内辐射缓慢变化的低频无线电噪声的基本新颖的准静态放电过程。
Low‐frequency radio noise is the electromagnetic background radiation which is compared here to the luminosity of 39 sprites recorded with a low‐light video camera. It is found that the sprite luminosities coincide with ∼10–30 ms long sudden enhancements of the electromagnetic background radiation ∼6–8 μV m−1Hz−1/2(∼6–9 dB) with a relative maximum near ∼125 kHz as measured with a wideband (∼1–400 kHz) digital radio receiver. The sprites cluster in 10 groups of 2–5 consecutive sprites which are paralleled by up to ∼1 s long slowly varying enhancements of the electromagnetic background radiation ∼4–5 μV m−1Hz−1/2(∼2–4 dB). The observed electric field strengths place an upper bound on the low‐frequency radiation from the electron multiplication associated with the exponential growth and branching sprite streamers predicted by Qin et al. [2012a]. This upper bound corresponds to a maximum of ∼300–5000 sprite streamers at ∼40 km height above thunderclouds. Some part of the observed electromagnetic background radiation might result from the superposition of low‐frequency radiation emanating from the quick succession of numerous horizontal lightning strokes and/or stepped leaders inside thunderclouds which would constitute a fundamentally novel quasi‐static discharge process inside thunderclouds radiating slowly varying low frequency radio noise.
宽带数字低频无线电接收机
影响因子：
2.4
作者：
Füllekrug M
通讯作者：
Füllekrug M
从卫星和地面观测推断出的 100 kHz 无线电波的跨电离层衰减
影响因子：
5.2
作者：
Fullekrug M
通讯作者：
Fullekrug M