Cloud-to-stratosphere lightning discharges: A radio emission model
Cloud-to-stratosphere lightning discharges: A radio emission model
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云平流层闪电放电：无线电发射模型
DOI：
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发表时间：
1992
期刊：
影响因子：
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通讯作者：
M. Desch
中科院分区：
文献类型：
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作者：
W. Farrell;M. Desch
最近对罕见的云到平流层闪电放电的观测表明，这些事件本质上是“缓慢上升”的，发射的能量在大约10毫秒内达到峰值。应用偶极辐射模型，我们表明，从这样的慢升事件发射的无线电波能量是最强的低于约50赫兹，并具有显着的滚降在较高的频率。在分析中，考虑了各种电流分布，以确定对无线电频谱的影响。在10 kHz附近，与典型的云对地回击相比，云对平流层闪电的发射显著减少，幅度低50 dB。这一结果可以解释为什么最近观测到的长期放电事件中没有检测到甚低频信号。
Recent observations of rare cloud-to-stratospheric lightning discharges suggest the events are inherently “slow-rising”, with the emitted energy reaching peak values in about 10 milliseconds. Applying a dipole radiation model, we demonstrate that the emitted radio wave energy from such slow-rising events is strongest below about 50 Hz, and possesses a significant rolloff at higher frequencies. In the analysis, various current distributions are considered in order to determine the effect on the radio spectrum. Near 10 kHz, the emission from cloud-to-stratospheric lightning is significantly reduced as compared to the typical cloud-to-ground return stroke, with amplitudes as much as 50 dB lower. This result may explain the lack of detection of VLF signals from recently observed long-lasting discharge events.