August eclipse left a wake in ionosphere, researchers reveal

While the phenomenon had long been theorized, the eclipse earlier this year was the first time researchers actually observed the waves.
By Ed Adamczyk Contact the Author   |  Updated Dec. 27, 2017 at 3:49 PM
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Dec. 27 (UPI) -- The August 21 solar eclipse caused waves in the uppermost part of the atmosphere, the ionosphere, which researchers say they were able to observe for the first time.

The eclipse across North America was seen by millions of people, as well as by 2,000 positioning sensors installed across its path on Earth by researchers of MIT's Haystack Observatory and Norway's University of Tromso.

Data from the sensors confirmed what scientists believed, but could not confirm until now: the rapid cooling and heating of the ionosphere, the earth's upper atmosphere, caused by the interruption and return of the sun's rays, made V-shaped atmospheric waves similar to that of the bow of a boat traveling through water.

In a paper published Tuesday in the journal Geophysical Research Letters, researchers detail "the first unambiguous evidence of ionospheric bow waves as electron content disturbances over central/eastern United States... [and] large ionospheric perturbations moving at the supersonic speed of the maximum solar obscuration which are too fast to be associated with known gravity wave or large-scale traveling ionospheric disturbance processes."

"This study reveals complex interconnections between the sun, moon, and earth's neutral atmosphere and ionosphere and demonstrates persistent coupling processes between different components of the Earth's atmosphere," the researchers wrote.

The waves were predicted in theoretical studies dating to the 1960s, but the August eclipse was the first time they were proven to exist on a wide scale.

"We were looking at some phenomena that were expected but never had the chance to be observed," Shun-Rong Zhang, one of seven authors of the research paper, told Gizmodo. "That was the surprise we found. We had a large coverage and our system is sensitive enough to be able to see these smaller variations."

The bow waves could be observed in the shadow, seen from Earth, caused by the moon passing before the sun.

Although the ionosphere contained both electrically charged and neutral particles, the waves dissipated before any damage to communications systems or the world's electrical grids could occur, Zhang added.

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