PRELIMINARY DISCHARGE PROCESSES IN LIGHTNING FLASHES TO GROUND
PRELIMINARY DISCHARGE PROCESSES IN LIGHTNING FLASHES TO GROUND
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DOI：
10.1002/qj.49708335603
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发表时间：
1957-01-01
影响因子：
8.9
通讯作者：
MALAN, DJ
中科院分区：
文献类型：
--
作者：
CLARENCE, ND;MALAN, DJ
通过使用不同的技术来记录在不同距离处发生的闪电放电的电气效应，可以整理出回击前电场变化的主要组成部分。这些场变化之间的比较表明，闪电对地的第一次回击之前通常有三个连续的和不同的放电过程。在3.6和1.4km高度云底附近的主要负电荷中心和正电荷中心之间的放电，从正极开始放电的频率可能与从负极中心开始放电的频率相同。这之后是第二阶段，在此期间，存在于云中的高导电通道被带负电。充电过程一直持续到通道前方的电场足够强，足以传播一个向下移动的阶梯先导击穿流光。阶梯先导已经被观测到先于超过75%的所有对地闪光，尽管大多数阶梯先导的辐射场非常小，只有使用非常高的放大率才能检测到。
By using different techniques of recording the electrical effects of lightning discharges occurring at varying distances, it has been possible to sort out the major components of pre‐return stroke field changes. A comparison between these field changes has shown that the first return stroke of a lightning flash to ground is usually preceded by three successive and distinct discharge processes.The first, or breakdown stage, is identified from the reversal of its field change with distance as a discharge between the main negative charge centre and the positive charge centre near the base of the cloud at heights of 3.6 and 1.4 km respectively, the discharge probably just as often starting from the positive as from the negative centre. This is followed by the second stage during which the highly conducting channel then existing in the cloud is being negatively charged. The charging continues until the field in front of the channel has become sufficiently strong to propagate a downward‐moving stepped leader breakdown streamer.Stepped leaders have been observed to precede more than 75 per cent of all flashes to ground, though the radiation fields of most stepped leaders are so small that they can only be detected by using very high amplification.The probable mechanisms involved in the preliminary stages are discussed.