A terrestrial gamma-ray flash, also known as dark lightning, is a burst of gamma rays produced in Earth's atmosphere. TGFs have been recorded to last 0.2 to 3.5 milliseconds, and have energies of up to 20 million electronvolts. From Wikipedia
A multi-sensor system in Japan confirms electron acceleration in lightning as the source of terrestrial gamma-ray flashes, revealing new insights into high-energy atmospheric processes.
