Electrical characteristics of narrow bipolar events
Electrical characteristics of narrow bipolar events
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DOI：
10.1029/2004gl021117
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发表时间：
2004-10
影响因子：
5.2
通讯作者：
K. Eack
中科院分区：
文献类型：
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作者：
K. Eack
窄双极事件（NBE）是一些雷暴中发生的一类独特的脉冲和高能云内放电的电磁特征。当宽带场变天线远距离观察时，NBE 的特点是强烈的 VHF 射频发射和双极波形。这些放电可能单独发生，也可能先于并可能引发传统的云内闪光。当近距离观察时，NBE 波形除了双极辐射场变化外，还表现出静电场变化。在极近的范围内，感应场和静电场在我们的测量中占主导地位。通过近距离观察和辐射场测量，我计算出平均而言，NBE 在 3.2 公里的距离上传输 0.3 C 的电荷，并且放电波前以等于光速一半的速度传播。
Narrow bipolar events (NBE) are the electromagnetic signature of a distinct class of impulsive and energetic intra‐cloud discharge that occurs in some thunderstorms. NBE are characterized by strong VHF RF emissions and bipolar waveforms when observed by broadband field‐change antennas at large distances. These discharges may occur in isolation or precede and perhaps initiate conventional intra‐cloud flashes. When observed at close range, NBE waveforms exhibit electrostatic field changes in addition to the bipolar radiation field change. At extremely close range, the induction and electrostatic fields dominate in our measurements. Using close‐range observations in conjunction with the radiation‐field measurements, I calculate that on average, an NBE transfers 0.3 C of charge over a distance of 3.2 km and that the discharge wave front propagates at a speed equal to one‐half the speed of light.