Lightning is a type of very high-energy phenomena in the world, and, in fact, they represent something more than just a bright flash of light and the roar of thunder. Lightning discharges, as has long been known, are the source of gamma-ray outbreaks, and recently a group of researchers from Japan found that these gamma-ray bursts are in turn the initiator of photonuclear reactions in the atmosphere, as a result of which antimatter is generated , immediately annihilating when in contact with ordinary matter.
Gamma flares from lightning discharges were recorded for the first time in 1992 with the help of the NASA Compton Gamma-ray Observatory. Since then, these outbreaks, called Terrestrial Gamma-ray Flashes (TGF), have been closely studied, and only recently researchers from the University of Kyoto managed to find explanations for some features of the signals from these flares.
“We have known for a long time that lightning discharges emit gamma rays, on the basis of this hypothesis that these gamma rays will provoke nuclear reactions in which atoms of some elements of the earth’s atmosphere take part,” says Teruaki Enoto ), the leading researcher, “The winter coast zone of Japan is an ideal place for observations of severe thunder and lightning.” In 2015, we began installing a network of miniature gamma sensors on the coast, and now the data collected by this and sensors, allowed us to uncover some of the mysteries of lightning discharges. ”
During the thunderstorm, which raged on February 6 this year, gamma sensors collected a very unusual set of data. Four sensors installed near the city of Kashiwazaki registered a strong gamma-ray burst immediately after a close lightning strike. But when scientists conducted a thorough analysis of the data, they found that in fact one burst consists of three consecutive bursts of different duration.
The first, shortest burst, lasting less than a millisecond, is the product of a lightning discharge. But the next two bursts are of more interest for scientists, because they are the result of photonuclear reactions that occur when the gamma rays of the first burst strike out neutrons from atmospheric nitrogen atoms. The knocked-out free neutrons are absorbed by other atoms, which leads to the appearance of a glow in the gamma range, which lasts for several tens of milliseconds.
The duration of the last, third gamma-ray burst is about one minute, and the cause of its appearance is even more exotic than the reason for the appearance of the second burst. The nitrogen atoms that have lost neutrons become unstable and decay, releasing positrons into space, which are a by-product of the cleavage reaction. Positrons are antipodes of electrons from the side of antimatter, and when they collide with normal electrons, they annihilate, mutually destroying each other. And such a process of “suicide” of electron positrons is also accompanied by flashes of gamma rays.
Soon, Japanese scientists plan to install a number of additional gamma sensors, which, together with 10 already available, will allow them to collect more data and study the phenomena described above even more thoroughly. “Many people believe that antimatter is something that exists only in fiction,” says Teruaki Enoto, “But we maintain that the process of the emergence and self-destruction of antimatter is the most common thing for the Earth, in some regions such phenomena occur many times almost every day. “