Tomorrow’s weather could be cloudy with a chance of electrons, thanks to a newly detected phenomenon in Earth’s magnetic shield.
Described as an unexpected and lightning-fast ‘electron rush’, the phenomenon occurs when waves of electromagnetic energy pulse through Earth‘s magnetosphere – the magnetic field generated by the churning of the earth’s core, which surrounds our planet and protects it from deadly solar radiation. These electrons then overflow from the magnetosphere and plunge towards the Earth.
However, the researchers added, electron showers can also pose a threat to astronauts and spacecraft in ways that space radiation models do not currently account for.
“Although space is commonly thought to be separate from our upper atmosphere, the two are inextricably linked,” said study co-author Vassilis Angelopoulos, professor of space physics at the University of California. in Los Angeles (UCLA). said in a press release. “Understanding how they are related can benefit satellites and astronauts traversing the region.”
Scientists have known for decades that energetic particles periodically rain down on our planet in small amounts. These particles come from Sun and sail through the 93 million mile (150 million kilometer) gap with Earth on the back of the solar wind.
Our planet’s magnetosphere traps many of these particles in one of two giant doughnut-shaped radiation belts known as the Van Allen Belts. Sometimes the waves generated in these belts cause the electrons to accelerate and fall into the Earth’s atmosphere.
The new study shows that electron showers can occur much more often than previous research thought possible.
In their new research, the study authors analyzed electron showers in the Van Allen belts using data from two satellites: the Electron Losses and Fields Investigation (ELFIN) spacecraft, a satellite of the size of a bread that orbits low in the Earth’s atmosphere; and the THEMIS (Time History of Events and Macroscale Interactions during Substorms) spacecraft, which orbits Earth beyond the Van Allen belts.
By monitoring electron fluxes in the Van Allen belts from above and below, the team was able to detect electron shower events in great detail. THEMIS data showed that these electron showers were caused by hissing waves – a type of low-frequency wave radio wave which originates during lightning strikes and then passes through the Earth’s magnetosphere.
These energetic waves can accelerate electrons in Van Allen belts, causing them to spill out and rain down on the lower atmosphere, the researchers found.
Additionally, data from the ELFIN satellite has shown that these rains can occur much more often than previous research suggested, and that they can become especially frequent during solar storms.
Current space weather models account for some sources of electron precipitation in the Earth’s atmosphere (such as solar wind impacts, for example) – however, they do not account for whistling-wave-induced electron showers, according to the researchers.
High-energy charged particles can damage satellites and pose hazards to astronauts caught in their path. By better understanding this source of electron rain, scientists can update their models to better protect the people and machines that spend their time above our planet, the authors of the new study said.