A discovered connection between lightning and Earth's radiation belts

Two scientists from the University of Alaska Fairbanks have discovered a new type of electromagnetic wave, called a "whistler," that transports energy from lightning to Earth's magnetosphere. This discovery could change our understanding of how storm energy affects Earth's space environment.


Researchers Vikas Sonwalkar and Amani Reddy identified what they call a "specularly reflected whistler," a wave that carries the energy from lightning from the ionosphere, at an altitude of 34 miles (55 kilometers), to the magnetosphere, above 500 to 620 miles (800 to 1,000 kilometers) in altitude. Contrary to previous beliefs, this energy is not confined within the ionosphere but reaches the radiation belts, two layers of charged particles that surround the Earth.

This discovery is crucial because the radiation belts directly influence the safety of satellites and other space technologies. A better understanding of waves like this "whistler" is essential to protect these technologies from damage caused by energetic particles in space.

The scientists were able to observe this phenomenon thanks to data from the Van Allen Probes satellites, launched by NASA in 2012, as well as information from the World Wide Lightning Location Network. They discovered that these "specularly reflected whistlers" are common in the magnetosphere, especially in regions where storms frequently occur.


This research also shows that these whistlers coexist with another already known type of wave, the "magnetospherically reflected whistler." However, the "specularly reflected whistler" might transport a larger share of the energy from lightning, particularly in tropical and subtropical areas.