December 2, 2024
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Lightning on Earth has released ‘killer electrons’ into orbit
High-energy electrons released by storms on Earth can threaten satellites and spacecraft
Lightning releases charged particles into Earth’s orbit.
Samuel Boivin/Getty Images
Atmospheric lightning can rain high-powered “killer electrons” into Earth’s orbit that form harmful radiation streams, new research suggests. Scientists previously thought that killer electrons could only appear in our planet’s distant radiation belt, but a study in the year Nature Communications he sees the lightning bolts unleashed in the much closer inner belt.
“These high-energy particles harm spacecraft and even humans in space,” says study author Lauren Blum, an astrophysicist at the University of Colorado Boulder. “Knowing when there are very high-energy electrons in the inner radiation belt would help us know when to avoid them.”
Electron precipitation occurs when charged particles, held in place by Earth’s magnetic field, are thrown from rest in one of the planet’s doughnut-shaped radiation belts. Analyzing data from NASA’s particle-tracking SAMPEX mission, the new study’s lead author Max Feinland (then an undergraduate student at Boulder) noticed something strange in the “microbubble” readings: rapid increases in electron precipitation recorded between 1996 and 1996. 2006. After designing an algorithm to find these spikes in the data, Feinland was surprised to see that readings of the inner radiation belt contained what many scientists believed were only energetic, slower electrons. Feinland and Blum, then Feinland’s research consultant, immediately began asking about possible causes. “People knew there was lightning-induced electron precipitation in the inner belt,” says Feinland, but “they didn’t really see it for electrons going that fast.”
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By comparing their microburst data National Lightning Detection Network data set, the researchers found a statistical probability that explosions in the inner belt coincide with lightning flashes. The electromagnetic waves released by the latter travel up the Earth’s magnetic field lines from the atmosphere and reach the inner radiation belt region, where their energy is sufficient to drive high-energy electrons out of their magnetic confinement.
The team’s findings are compelling because no one seems to have made such a connection before, says space weather scientist Steven Morley of Los Alamos National Laboratory. This area of research has data limitations, he added, because few measurements have been taken since SAMPEX ended two decades ago. But he says that the study is “very exciting, even with very limited data. It really opens up a lot of other questions.”
These findings are a “wake-up call” about how Earth and space weather are linked, Blum says; this connection can have consequences for the ozone layer, the chemistry of the atmosphere and even the climate. “We cannot study the dynamics from the sun to Earth and the radiation belt separately,” he says. “We need to understand what’s going on down there in our atmosphere and in Earth’s weather systems as well.”
