闪电的20 MHz辐射与放电过程

LIGHTNING RADIATION AT 20 MHz AND DISCHARGE PROCESS

利用一台窄带高频接收机对20MHZ的闪电辐射场进行了测量,并利用—慢天线电场变化仪配合观测以区分对地放电中的各放电过程,得到了地闪各闪击过程及云闪的辐射强度和辐射时间。我们认为云闪的k变化、地闪中的第一次闪击是20MHZ的最强辐射源,以后的闪击次之,并逐步减弱。

Simultaneous measurements of lightning radiation at 20 MHz and electric field change due to a lightning discharge were obtained by using a narrow bandwidth receiver and a slow antenna. The discharge processes, such as stepped leader, return stroke, etc., of ground discharge were identified. The radiation intensity and the duration for both cloud discharge and return strokes of ground discharge are presented. It was found that the K change of cloud discharge and the frist return stroke of ground discharge have the strongest radiation at 20 MHz. The radiation becomes weaker and weaker for subsequent strokes.