Recently for a number of thunderstorm systems in different regions of the planet there have been reports of observations of high frequency radio emission with duration varying from several to more than one hundred of milliseconds which may both be isolated or precede the lightning initiation. There is a consensus that this radiation originates from continuous sequences of short-duration discharges that randomly fill the areas of strong electric field between the main negative and the upper positive charge regions. But the concrete physical mechanism of discharge activity evolution and its contribution to the lightning leader formation remain unclear. To answer these questions several hypotheses were proposed, among which the runaway breakdown and fast positive discharge can be accentuated. In this study, we present another explanation which is based on comparison of experimental data of thundercloud radio activity obtained in the Nizhny Novgorod region of the Russian Federation on May 15, 2019 with the use of a wide band radio interferometer with the results of our numerical simulation of the lightning leader formation in the active part of a thundercloud. It is shown that the observed intense electric field bursts can originate from mergers of two or more streamer systems or bipolar leaders with lengths ranging from several to several tens of meters. In the framework of our approach, the sequence of such mergers can, under certain conditions, result in the self-sustaining leader channel formation finishing the lightning initiation process.

最近，对于地球不同地区的许多雷暴系统，有报告称，观测到持续时间从几毫秒到一百多毫秒不等的高频无线电发射，这可能是孤立的，也可能是在闪电开始之前。人们一致认为，这种辐射源自连续的短时放电序列，这些放电随机填充主要负电荷区和上正电荷区之间的强电场区域。但放电活动演化的具体物理机制及其对闪电先导形成的贡献尚不清楚。为了回答这些问题，提出了几个假设，其中可以强调失控击穿和快速正放电。在这项研究中，我们提出了另一种解释，该解释基于 2019 年 5 月 15 日在俄罗斯联邦下诺夫哥罗德地区使用宽带无线电干涉仪获得的雷云无线电活动实验数据与我们对闪电的数值模拟结果的比较雷云活动部分的领导者形成。结果表明，观察到的强电场爆发可能源于两个或多个拖缆系统或双极前导的合并，长度从几米到几十米不等。在我们的方法框架中，在某些条件下，这种合并的顺序可以导致自我维持的先导通道形成完成闪电引发过程。