Ultra-fast ‘electronic showers’ hit Earth much more often than we thought

(ORDO NEWS) — Tomorrow’s weather could be cloudy with a chance of electrons, according to a recent discovery in the Earth’s magnetic shield.

Described as an unexpected, ultra-fast “electron fallout,” this phenomenon occurs when waves of electromagnetic energy travel through Earth’s magnetosphere, the magnetic field created by the rotation of the Earth’s core that surrounds our planet and shields it from deadly solar radiation. Then these electrons fly out of the magnetosphere and fall to the Earth.

Heavy electron showers most commonly occur during solar storms, and they may contribute to boreal aurora, according to a study published March 25 in the journal Nature Communications.

However, the researchers added, electron showers could also pose a threat to astronauts and spacecraft, as cosmic radiation models currently do not account for them.

“While space is commonly thought to be separate from our upper atmosphere, the two are inextricably linked,” study co-author Vassilis Angelopoulos, a professor of space physics at the University of California, Los Angeles (UCLA), said in a statement. “Understanding how they are connected could benefit satellites and astronauts flying through the region.”

Scientists have known for decades that energetic particles periodically fall on our planet in small amounts. These particles originate in the Sun and travel across a 93 million mile (150 million km) gap to Earth on the back of the solar wind.

Our planet’s magnetosphere traps many of these particles in one of two giant donut-shaped radiation belts known as the Van Allen belts. From time to time, waves generated in these belts cause electrons to accelerate and fall into the Earth’s atmosphere.

A new study shows that showers of electrons may occur much more frequently than previously thought.

In their new study, the authors analyzed electron showers in the Van Allen belts using data from two satellites: the Electron Loss and Fields Investigation (ELFIN) spacecraft, a bread-loaf-sized satellite that orbits low in Earth’s atmosphere; and the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft, which orbits outside the Van Allen belts.

By observing the electron streams in the Van Allen belts from above and below, the team was able to detect electron rain events in great detail.

THEMIS data showed that these electron showers were caused by Whistler waves, a type of low-frequency radio waves that are generated during lightning strikes and then travel through the Earth’s magnetosphere.

These waves of energy can accelerate electrons in the Van Allen belts, causing them to shimmer and rain down into the lower atmosphere, the researchers found.

In addition, data from the ELFIN satellite has shown that these showers may occur much more frequently than previous studies have suggested, and may become especially common during solar storms.

Existing space weather models take into account some sources of electrons falling into the Earth’s atmosphere (for example, solar wind impacts), but, according to the researchers, they do not take into account electron showers caused by whistler waves.

High-energy charged particles can damage satellites and pose a danger to astronauts who get in their way. A deeper understanding of this source of e-rain will allow scientists to update their models to better protect the people and machines that spend time high above our planet, the authors of the new study say.

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