NASA details Parker Solar Probe’s groundbreaking Sun discoveries

James Marshall
December 5, 2019

ANN ARBOR-Our closest-ever look inside the sun's corona has unveiled an unexpectedly chaotic world that includes rogue plasma waves, flipping magnetic fields and distant solar winds under the thrall of the sun's rotation, according to University of MI researchers who play key roles in NASA's Parker Solar Probe mission.

The U-M findings, part of the first wave of results from the spacecraft that launched in August 2018, provide important insights into two fundamental questions the mission was created to answer: Why does the sun's corona get hotter as your move further away from the surface? The information was published in the journal Nature. As the wind's particles stream out of the cooler coronal holes, they move along the magnetic field lines. The findings, offering fresh details about how the sun spawns space weather, are reshaping astronomers' understanding of violent solar wind that can hamper satellites and electronics on Earth. In October 2018, the probe came within 26.55 million miles (42.3 million kilometers) of the sun, surpassing the record set by the Helios 2 spacecraft in 1976.

Parker's data also provided unprecedented detail on coronal mass ejections, billion-ton clouds of solar materials hurtling out into the solar system, according to the study. Researchers knew that close in, the sun's magnetic field pulls the wind in the same direction as the star's rotation.

A coronal hole (black region) at a slanted angle almost centred on the face of the Sun. "They carry a tremendous amount of energy".

"We can see the magnetic structure of the corona, which tells us that the solar wind is emerging from small coronal holes; we see impulsive activity, large jets or switchbacks which we think are related to the origin of the solar wind; we see instability - the gas itself is unstable and is generating waves on its own". The energised and accelerated particles moving away from the Sun due to the solar wind could affect the global power grid and telecommunications on Earth. We wondered if these waves could be heating the corona and if they would be stronger closer to the sun. "We've already seen evidence for some very surprising phenomena-which you should always expect when you travel into regions where spacecraft have never been before". "We are now seeing what's happening to the dust near the sun".

Kasper said findings also showed that the wind rotates around the sun between ten and 20 times faster than models had predicted.

Scientists released the first results from the mission Wednesday. By the end of its 7-year-long mission, the spacecraft will have circled the Sun a total of 24 times. That is already closer to the Sun than Mercury, but the spacecraft will get even closer in the future as it travels at more than 213,000 miles per hour, faster than any previous spacecraft.

Stuart Bale, professor of physics at the University of California Berkeley, recalled that a "major space weather event" in 1859 blew out telegraph networks on Earth and one in 1972 set off USA naval mines in North Vietnam.

Parker, now 92, is poring over the probe's early results with interest. At this point, the team will be looking to see if their initial findings are repeated and if spikes in these rogue waves get even stronger as the spacecraft gets closer to the surface.

Other reports by Click Lancashire

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