(Image courtesy of University Of Florida Lightning Research Group)
How lightning works is still pretty much a mystery. But this summer, some large steps to understanding it’s movement were made. Until recently, there wasn’t fast enough camera technology to capture an x-ray image of lightning.
A new camera has a resolution sharp enough to reveal a bright ball of x-rays at the head of the bolt, with almost no lingering radiation along the bolt’s trail. The X-ray glow follows a so-called lightning leader â€“ a channel in the air that forms a path for the lightning. The leader’s charged tip creates an electric field that accelerates electrons almost to the speed of light and causes the X-ray emissions.
The lightning leader is also known as a step leader, because it seems to travel by leaps and bounds rather than in a continuous line. The trail left by the step leader allows negative charge to travel down, even as positively charged leaders travel upward from the ground to meet in the middle. That triggers a so-called return stroke moving upward from the ground toward the cloud â€“ the flash of what human eyes see as lightning.
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