Record thunderstorm had electric potential of 1.3B volts

March 20 (UPI) -- Scientists have reported a new record for the most powerful thunderstorm on record. The massive storm boasted an electric potential of 1.3 billion volts.

To estimate the storm's electric potential, scientists measured the decrease in the number of muons beneath the storm. Muons are tiny particles that rain down through the atmosphere. They're produced when cosmic rays collide with the upper atmosphere.

Scientists in India and Japan determined that the electricity pulsing through thunderclouds would reduce the charges of muons passing through, diminishing the odds of the particles being detected by muon sensors beneath the storm.

Data collected by airplanes and weather balloons have helped scientists study the electrical structures inside thunderstorms, but planes and balloons can only survey small portions of storms that spread out across large amounts of space. They can't measure the electric potential across the entirety of a massive cloud.

Astronomers have previously noticed that the presence of thunderstorms can depress the flow, or flux, of muons measured by muon telescopes. Researchers have also discovered correlations between lightning strikes and gamma rays.

For the study, scientists used the G3MT, a muon telescope in Southern India, to precisely measure the impact of thunderclouds on muon flux.

Study authors, led by Sunil Gupta of the Tata Institute of Fundamental Research in Mumbai, India, also developed a quantitative method for deducing the electric potential of the thunderstorm based on changes in muon flux.

"We realized that GRAPES-3 is an ideal tool for measuring thunderstorm potentials, in particular for the biggest storms," Gupta said in a news release.

G3MT was able to measure changes in muon flux with a precision of 0.1 percent. The telescope was also able to differentiate between 169 discrete directions in the sky, providing a comprehensive picture of the thunderclouds electric structure.

"This muon-based technique provides a unique, albeit indirect, way to probe the electric fields in the largest natural particle accelerators on Earth -- lightning and thunderstorms," said Michael Cherry, who studies cosmic and gamma rays at Louisiana State University.

Between 2011 and 2014, scientists used G3MT and their novel quantitative method to measure the electrical potential of 184 thunderstorms. On December 1, 2014, the team measured a thundercloud with an electric potential of 1.3 billion volts, or 1.3 gigavolts -- the most powerful electric storm ever measured.

Scientists described the record storm in the journal Physical Review Letters.