A cohort of telescopes has captured a special kind of aurora strung across the night sky like a shining jeweled necklace, helping astronomers better understand the mechanics behind these magnificent light shows.
Known as auroral beads, these round beads auroras appear in scattered groups across the sky, while more traditional auroras appear flatter and more elongated. A group of 13 spacecraft, including the European Space Agency’s (ESA) Cluster mission, observed the process that triggers auroral beads on the dayside of Earth, or facing the sun, offering new clues as to how these unique auroras are forming.
Auroras are caused by electrical storms or charged particles emitted by the Sun. Observations collected on Nov. 6, 2018, revealed that vortices at the edge of Earth’s magnetosphere – the magnetic field that surrounds our planet and shields it from solar radiation – allow some of the sun’s charged particles to make their way to Earth’s surface. , creating streams of auroral beads, according to a statement from the ESA.
The spacecraft were located on the night side of Earth, near the planet’s magnetopause, the thin boundary at the outer edge of the magnetosphere. While some spacecraft observed the vortices, others observed the streams of particles flowing towards Earth. The combination of these observations allowed researchers to study the entire process of auroral pearl formation for the first time, according to the release.
“This discovery shows that the Cluster spacecraft is part of a ‘magnetospheric orchestra’ of missions that together enable additional science that is not possible to achieve with each mission individually,” said Philippe Escoubet, project scientist for ESA’s Cluster mission, in the press release.
The whirlpool-like vortices that provide a fast track for solar particles form when solar wind blows past the Earth’s magnetopause, like the wind that lifts the oceans and clouds. In turn, electrons from the solar wind spiral towards the magnetosphere and eventually reach Earth’s upper atmosphere, where electrons interact with hydrogen, oxygen and nitrogen. This causes the molecules to glow and form round auroral beads that appear to be strung across the sky.
“It’s great to use multi-satellite missions to make connections between the dynamics at the periphery of the magnetosphere and what we see in the ionosphere well below,” Steven Petrinec, a physicist at Lockheed Martin Space and lead author of a study describing the findings, said in the release. “Due to the paucity of observations and sampling locations in the magnetosphere, it is important to take full advantage of multiple mission observations whenever possible to understand the connections between the different processes within the large and complex system. »
These observations demonstrate how using multiple spacecraft placed at different vantage points can provide a more complete view of space. The instrument cluster included four spacecraft from ESA’s Cluster mission, NASA’s four magnetospheric multiscale spacecraft, three macroscale event and interaction history spacecraft during sub- thunderstorms, the Geotail satellite and a satellite from the US Defense Weather Satellite Program.
The results were published in the journal Frontiers in astronomy and space science.
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