CONTINUING CURRENTS IN CLOUD-TO-GROUND LIGHTNING DISCHARGES
CONTINUING CURRENTS IN CLOUD-TO-GROUND LIGHTNING DISCHARGES
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DOI：
10.1029/jz067i002p00637
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发表时间：
1962-01-01
影响因子：
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通讯作者：
BROOK, M
中科院分区：
文献类型：
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作者：
KITAGAWA, N;WORKMAN, EJ;BROOK, M
在1959年和1960年，我们从非常活跃的雷暴中获得了大约200张云对地放电的优秀照片，这些照片是用新设计的旋转胶片相机拍摄的。在两个具有不同时间分辨率的示波器上同时记录所拍摄放电的电场变化和亮度变化。50%的多行程闪光，约占云地闪光的90%，被发现涉及至少一个行程，随后是持续40至500毫秒的非常长的持续亮度。这种连续的亮度包含了许多相对较亮的成分，基本上与M成分相同，它们被认为是跟随一些具有很短时间间隔的笔画。对连续发光的电场分析表明，在发光期间，云的负电荷不断地流向地面。在持续亮度期间的电流浪涌（M分量）与小的快速场变化（K变化）有关，并且M分量之间的时间间隔在统计上与通常在云-地闪光的间隔和最后期间观察到的K变化之间的时间间隔相同。在持续发光期间，闪电通道保持一个足够高的电导率水平，以支持瞬时电流增加，而不涉及先导过程。在通道失去亮度后，它会保持较低的传导率水平7至100毫秒，在此期间的后续中风也可以遵循相同的通道。当经过较长时间（>100 msec）时，后续笔划（如果有的话）采用具有新的步进式先导的不同通道。
About 200 excellent photographs of cloud‐to‐ground discharges, taken with a newly designed rotating‐film camera, were obtained from very active thunderstorms in 1959 and 1960. The electric‐field changes and luminosity variations of the photographed discharges were recorded simultaneously on two oscilloscopes having different time resolution. Fifty per cent of the multiple‐stroke flashes, constituting about 90 per cent of cloud‐to‐ground flashes, are found to involve at least one stroke which is followed by very long continuing luminosity lasting for 40 to 500 msec. This continuing luminosity contains a number of relatively brighter components essentially the same as theMcomponents which are known to follow some strokes having very short time intervals. The analysis of the electric field associated with the continuing luminosity reveals that, during the luminous period, negative charge from the cloud flows to ground continuously. The surges of current (Mcomponents) during the continuing luminosity are associated with the small rapid field changes (Kchanges), and the time interval betweenMcomponents is statistically the same as that between theKchanges generally observed during the interstroke and final period of cloud‐to‐ground flashes. During the period of continuing luminosity, the lightning channel maintains a level of conductivity which is high enough to support a momentary current increase without involving the leader process. After the channel loses its luminosity, it maintains a lower level of conductivity for 7 to 100 msec, and a subsequent stroke during this period can also follow the same channel. When a longer time elapses (>100 msec), a subsequent stroke, if any, takes a different channel with a new stepped leader.