With LOFAR we have been able to image the development of lightning flashes with meter‐scale accuracy and unprecedented detail. We discuss the primary steps behind our most recent lightning imaging method. To demonstrate the capabilities of our technique we show and interpret images of the first few milliseconds of two intracloud flashes. In all our flashes, the negative leaders propagate in the charge layer below the main negative charge. Among several interesting features we show that in about 2 ms after initiation the primary initial leader triggers the formation of a multitude (>10) negative leaders in a rather confined area of the atmosphere. From these only one or two continue to propagate after about 30 ms to extend over kilometers horizontally while another may propagate back to the initiation point. We also show that normal negative leaders can transition into an initial leader like state, potentially in the presence of strong electric fields. In addition, we show some initial breakdown pulses that occurred during the primary initial leader, and even during two “secondary” initial leaders that developed out of stepped leaders.

中文翻译：

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高分辨率成像的云闪电的初始阶段

借助LOFAR，我们能够以米级的精度和前所未有的细节为闪电的发展成像。我们讨论了最新雷电成像方法背后的主要步骤。为了演示我们技术的功能，我们显示和解释两次云内闪烁的前几毫秒的图像。在我们所有的闪烁中，负引导线在主负电荷下方的电荷层中传播。在几个有趣的特征中，我们表明，在启动后大约2毫秒内，初始初始引导触发了在相当狭窄的大气区域中形成大量（> 10）负引导的形成。从这两个中，只有一个或两个继续在大约30毫秒后传播，以水平延伸数千米，而另一个可能传播回到起始点。我们还表明，正常的负引导可能会在存在强电场的情况下转变为类似状态的初始引导。此外，我们还显示了一些主要的初始击穿脉冲，这些脉冲发生在主要的初始引导者之间，甚至发生在两个由阶梯状引导者形成的“辅助”初始引导者中。