Scientists have discovered a connection between lightning in the Earth’s atmosphere and the appearance of electrons at near-light speeds in the Van Allen radiation belts around the planet. In ten years of satellite observations, such events are often separated by intervals of less than a second, indicating a direct connection. This means that weather on Earth has a direct impact on near-Earth space weather, which can have a negative impact on satellites and astronauts.
A photo of a thunderstorm from aboard the ISS. Image source: NASA
The Van Allen Belts are two relatively stable regions of space around the Earth that act as a trap for high-energy particles from space and the Sun. The belts are formed by the planet’s magnetic field: the inner belt extends from 640 to 9,600 km, and the outer – from 13,500 to 58,000 km. Without this protection, the Earth’s surface would be cleared of all biological life by radiation. Electronics are also afraid of high-energy particles, which can cause both glitches and direct damage to chips.
A team of scientists led by Max Feinland of the University of Colorado in Boulder analyzed satellite observations of activity in the Van Allen belts between 1996 and 2006 and found 45 bursts of high-energy electron clouds there at speeds close to the speed of light. Such particles easily left the Van Allen belt regions and became a threat to both astronauts and satellites in all orbits. But what is most surprising is that a series of events occurred immediately after lightning discharges in the Earth’s atmosphere.
Schematic representation of Van Allen belts
Traditionally, people in orbit and satellite operators have been warned of radiation hazards from solar activity, whether simple flares or coronal mass ejections. Nobody takes into account the appearance of high-energy particles from the rear, but now scientists need to more carefully study the process of their birth and, it is possible that a new threat profile will thereby appear. So far, researchers believe that electromagnetic waves generated by lightning discharges – the so-called atmospherics (Whistler waves in foreign literature) – provoke a chain reaction in clouds of low-energy electrons in the Van Allen belts, which leads to the appearance of killer electrons and their scattering in all directions.