A brand new slow-motion video gives one of the best view but of the split-second collision of electrical currents that creates a flash of lightning.
The video captures a thread of electrical present, or lightning chief, zipping down from a thundercloud to satisfy one other chief reaching up from the bottom. When the 2 contact, it triggers a a lot stronger present to surge between the cloud and floor, and lightning flashes.
A single strand of electrical energy, or streamer, on the frayed tip of every lightning chief is sufficient to forge the connection between the 2 currents, researchers report on-line February 1 in Geophysical Analysis Letters. Understanding this cloud-to-ground connection is essential as a result of it determines the place lightning strikes (SN: 6/25/20).
Streamers on the ideas of lightning leaders had been identified to link these currents collectively. However as a result of streamers are so faint and lightning leaders merge in mere millionths of a second, it was unclear precisely how they fused collectively. The link could possibly be solid by many overlapping streamers coalescing right into a single channel of electrical present, or by contact between single streamers from every chief.
Lightning is quick, however high-speed cameras are quicker — permitting scientists to view the play-by-play of how lightning flashes kind (proven left to proper, every body 2.6 millionths of a second aside). When an electrical present touring down from a cloud meets one reaching up from the bottom, a single skinny strand of electrical energy bridges the hole (pink field), triggering a flash of lightning.R. Jiang et al/Geophysical Analysis Letters 2021Rubin Jiang, an atmospheric scientist on the Chinese language Academy of Sciences in Beijing, and colleagues caught two lightning leaders on tape in 2017, throughout a lightning storm. Utilizing a high-speed digicam that snapped an image of the lightning bolt each 2.6 microseconds, Jiang and colleagues noticed a play-by-play of what occurred when the perimeter of streamers on the tip of every lightning chief met.
A single glowing filament of electrical energy appeared between the leaders proper earlier than the flash of lightning. That implies that the hairline connection between the primary two streamers to the touch channeled the torrent of electrical present that shaped the lightning flash, whereas the opposite streamers fizzled out (SN: 2/15/19).
Behold: the split-second collision of electrical currents that creates a flash of lightning. A present reaches down from a cloud. It meets one other reaching up from the bottom. When a single tenuous thread of electrical energy bridges the hole between them, lightning flashes.