Magnetic waves make the Sun’s corona chemically different from the other layers of the star

The Sun’s corona – the outermost layer that can reach temperatures of over a million degrees Celsius – is very different chemically from the rest of the star, despite being physically connected.

Astronomers have been unable to explain and prove this phenomenon for more than half a century, making it one of the enduring puzzles of astronomy.

Now, researchers have found the first observational evidence that magnetic waves in the chromosphere – the sun’s middle layer – split up the plasma, forcing only charged ions into the corona, leaving neutral particles behind.

An article published today by astronomers from University College London and the Italian Space Agency provides the first ever evidence to support this long-held theory.

Researchers analyzed data from New Mexico and space telescopes to simultaneously observe the same part of the sun in an attempt to find the waves.

The observed patterns were recreated using computer modeling, and scientists found that waves reflecting in the chromosphere were magnetically linked to regions of abundant ionized particles in the corona.

“These results indicate a link between the chromospheric activity of sunspots and observable changes in the composition of the coronal plasma,” the researchers write in their study, published today in The Astrophysical Journal.

The theory of magnetic waves splitting plasma and forcing ions towards the corona was first postulated in the 1960s.

What causes the waves is still unknown, but scientists believe they are generated in the volatile corona by millions of mini-explosions, also known as nanoflares.

Dr. Deborah Baker, lead author of the study, told MailOnline: “The different chemical compositions of the sun’s inner and outer layers were first noticed over 50 years ago.

This discovery has led to what is one of the long-standing open questions in astrophysics.

‘The difference in composition is surprising, given that the layers are physically connected and that matter in the corona comes from the innermost layer, the photosphere.

Now, a unique combination of near-simultaneous observations from the ground and in space of the solar atmosphere has made it possible to definitively detect magnetic waves in the chromosphere and link them to an abundance of elements in the corona. that are not found in the innermost regions of the sun. ‘

Dr. Marco Stangalini of the Italian space agency in Rome says the findings are true for other stars as well as the sun.

“By observing our local laboratory, the sun, we can improve our understanding of the universe far beyond,” he says.

Astronomers are now more interested than ever in the Sun’s corona because of its role in creating the solar wind.

It is the solar wind, which carries ions 92 million miles from the sun to the earth, that creates the northern and southern light.

When these charged particles reach the Earth’s magnetic field, which is most powerful at the poles, they release energy and this manifests itself as the mesmerizing celestial light show we see on Earth, visible at high and low latitudes.

However, when the steady stream of charged particles turns into a deluge after a violent regurgitation from the sun’s surface, it can affect delicate electrical systems and satellite-dependent industries.

“Identifying the processes that make up the corona is crucial because we are trying to better understand the solar wind, a stream of charged particles that flow out from the sun and can disrupt and damage Earth’s satellites and infrastructure,” says Dr. Baker. .

“Our new findings will help us analyze the solar wind and trace back where it comes from in the sun’s atmosphere.”