Exploding Stars May Reveal How Lightning is Created in Storms

How is lightning created? That's a difficult question and now, scientists have used studies on exploding stars to help unlock the answer.

It's difficult to measure electric fields inside large, dangerously charged clouds. In this case, though, scientists discovered that cosmic rays provide suitable probes to measure electric fields within thunderclouds. More specifically, the researchers used measurements from the LOFAR radio telescope.

"We used to throw away LOFAR measurements taken during thunderstorms. They were too messy," said Pim Schellart, one of the researchers, in a news release. "Well, we didn't actually throw them away of course, we just didn't analyze them."

High in the atmosphere, particles strike atmospheric molecules and create "showers" of elementary particles. These showers can be measured from the radio emission that is generated when their constituent particles are deflected by the magnetic field of the Earth. The radio emission also gives information about the original particles.

"We modeled how the electric field in thunderstorms can explain the different measurements," said Schellart. "This worked very well. How the radio emission changes gives us a lot of information about the electric fields in thunderstorms. We could even determine the strength of the electric field at a certain height in the cloud."

The researchers found that the field can be as strong as 50 kv/m, which translates to a voltage of hundreds of millions of volts over a distance of multiple kilometers.

The new findings to measure electric fields in thunderclouds may contribute to a better understanding and better predictions of lightning activity. Current measurement methods are too localized. In contrast, cosmic waves can probe thunderclouds from top to bottom and give researchers a better understanding of lightning and thunderstorms.

The scientists hope to develop the model further and eventually answer the question how lightning is created within thunderclouds.

The findings are published in the journal Physical Review Letters.

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