Space & Cosmos

“Killer Electrons”: Thunderstorms play space weather and space pinball

Visualization showing how magnetic field lines, thin lines in cyan color, orbiting the Earth can trap charged particles, thin lines in yellow color. Credit: UCLA EPSS/NASA SVS

When lightning strikes, electrons rain down. In a new study, researchers led by undergraduate students at the University of Colorado Boulder have discovered a new relationship between Earth’s weather and space weather. The researchers used satellite data to show that thunderstorms on Earth emit particularly high-energy, or “super-hot,” electrons from the inner radiation belt, a region of space surrounded by charged particles that surrounds the Earth like an inner tube. He made it clear that he could be kicked out.

The team’s findings could help satellites and even astronauts avoid dangerous radiation in space. Lead author and undergraduate student Max Feinland said this is the kind of downpour you don’t want to get caught in.

“These are scary particles, or what some people call ‘killer electrons,'” said Feinland, who earned a bachelor’s degree in aerospace engineering from UW-Boulder in spring 2024. “They penetrate the metal of the satellite, hit the circuit boards, and can be dangerous.” They are carcinogenic if they hit people in space. ”

The study was published October 8 in the journal Nature Communications.

This discovery drew attention to the radiation belts produced by Earth’s magnetic field. Lauren Bloom, a co-author of the paper and an assistant professor at UW Boulder’s Laboratory for Atmospheric and Space Physics (LASP), explained that two of these regions surround the Earth. It begins more than 600 miles above the Earth’s surface. The outer belt begins approximately 12,000 miles from Earth. These floating pools in space trap charged particles flowing toward Earth from the Sun, forming a kind of barrier between Earth’s atmosphere and the rest of the solar system.

However, it is not completely airtight. For example, scientists have long known that high-energy electrons can fall toward Earth from the outer radiation belts. But Blum and her colleagues were the first to discover that similar rain was coming from inside the belt.

In other words, Earth and space may not be as separate as they seem.

“Weather in space is really influenced from above and below,” Blum says.

bolt from blue

It is a testament to the power of lightning.

When lightning flashes in Earth’s skies, that burst of energy can also send radio waves spiraling deep into space. When these waves collide with electrons in the radiation belt, they can push them away, much like waving an umbrella to flick water away. In some cases, such “lightning electron drop” can even affect the chemistry of Earth’s atmosphere.

Until now, researchers had only collected direct measurements of low-energy, or “cold” electrons falling from the inner radiation belt.

“Inner belts are usually considered boring,” Blum says. “It’s stable. It’s always there.”

A lightning strike starts an electronic pinball game in space.

Visualization of the radiation belts surrounding the Earth. Credit: NASA

Her team’s new discovery happened almost by chance. Feinland was analyzing data from NASA’s now-defunct Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) satellite when he discovered something strange. A mass of high-energy electrons moves through the inner belt.

“I showed Lauren some of my events and she said, ‘That’s not where it’s supposed to be,'” Fineland said. “Some literature suggests that there are no high-energy electrons in the inner belt.”

The team decided to dig deeper.

Feinland counted a total of 45 surges of high-energy electrons in the inner belt from 1996 to 2006. He compared these events to records of lightning strikes in North America. Sure enough, some of the electron spikes appeared to occur within a second of lightning striking the ground.

electronic pinball

Here’s what the research team thinks is happening. After a lightning strike, radio waves from Earth begin a kind of frenzied pinball game in space. They collide with electrons in the inner belt, and the electrons begin to shuttle back and forth between Earth’s northern and southern hemispheres, doing so in just 0.2 seconds.

And each time an electron bounces, some of it falls off the belt and into the atmosphere.

“You have a big clump of electrons that bounces back and bounces back again,” Blum says. “You see this initial signal, but it fades away.”

Bloom doesn’t know how often such events occur. They can occur primarily during periods of high solar activity, when the sun spits out large amounts of high-energy electrons and traps these particles in an inner belt.

Researchers believe a better understanding of these phenomena could allow them to predict when they will occur, potentially helping keep people and electronics safe in orbit. .

For his part, Feinland is grateful for the opportunity to study these epic storms.

“I didn’t realize how much I loved research until I started working on this project,” he says.

Other co-authors of the new study include Robert Marshall, associate professor in the Ann and H.J. Smead School of Aerospace Engineering Sciences at UW Boulder, Longji Gan of Boston University, and Johns Hopkins University Applied Physics Laboratory. and Mark Looper of the Institute of Science. Aerospace Co., Ltd.

Further information: Max Feinland et al., Lightning-induced relativistic electron precipitation from the internal radiation belts, Nature Communications (2024). DOI: 10.1038/s41467-024-53036-4

Provided by University of Colorado Boulder

Citation: “Killer Electrons”: Lightning Storms Play Space Pinball with Space Weather (October 12, 2024), https://phys.org/news/2024-10-killer-electrons-lightning-storms-play Retrieved from October 12, 2024. html

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