Data from nanosatellites designed to study particle flows in the atmosphere has helped discover a new source of ultrafast electrons that hit Earth and cause a type of aurora. The study showed that the number of “falling” electrons and their influence is significantly underestimated by existing theories.

Scientists from the University of California, Los Angeles, based on the analysis of satellite data, found that the rain of electrons that “falls” at the Earth’s poles is caused by whistling waves generated in the radiation field of our planet.

In their work, scientists used observations of a rain of electrons from near-Earth orbit using the ELFIN nanosatellites, specially designed to observe particle flows. The data from these satellites were combined with observations from the THEMIS (NASA project for the study of the magnetosphere) space project.

The near-Earth space environment is very dynamic and filled with charged particles orbiting the planet in giant rings called radiation belts, the researchers note. Electrons in the radiation belts move in a spiral between the north and south magnetic poles of the Earth.

Scientists have seen that under certain conditions, electromagnetic oscillations called whistlers can occur in the radiation belts, exciting and accelerating electrons so strongly that they can be thrown into the atmosphere, creating electron rain.

Current space weather models do not account for this additional electron flow, the study authors note. But not only does it create beautiful auroras, it can damage low-orbiting satellites and affect the chemical composition of the atmosphere.

The research team also showed that the fall of electrons from the radiation belt to the earth increases significantly during geomagnetic waves.

“Taking into account the influence of the fall of electrons on the atmosphere is important not only for ground-based modeling, but also for understanding the Earth’s magnetic environment, predicting hazards for satellites, astronauts and other space infrastructure,” the scientists note.