A team of physicists at Northumbria University, UK, has found that the Sun’s magnetic waves behave differently than believed.

Researchers have reported their findings in Nature Astronomy.

Northumbria University’s Dr. Richard Morton and colleagues examined data gathered over a 10-year period. So, they found that sound waves escaping out from the Sun can excite the magnetic waves in the Sun’s corona – the outermost layer of the Sun’s atmosphere. The corona remains hidden due to the bright light of the Sun’s surface. So, scientists can only see it using special instruments.

These waves are also responsible for heating and accelerating powerful solar wind from the Sun which travels through the Solar System.

The winds travel at speeds of around a million miles per hour. They also affect the atmosphere of stars and planets, impacting on their own magnetic fields, and cause phenomena such as Aurora.

These magnetic waves, known as Alfvénic waves, are low-frequency traveling oscillation of the ions and the magnetic field. Scientists previously thought the waves originate at the sun’s surface, where boiling hydrogen reaches temperatures of 6,000 degrees and churns the sun’s magnetic field.

Scientists named these waves after Hannes Alfvén who in 1942 proposed the existence of electromagnetic-hydrodynamic waves. These waves can carry energy from Sun’s photosphere to heat up the corona and the solar wind.

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However, the researchers discovered that the sound waves leave a distinctive marker on the magnetic waves.

This finding suggests that sound waves cause the entire corona to shake or vibrate in a collective manner over a very distinct range of frequencies.

This newly-discovered marker was consistently present over the 10-year time-span examined. This suggests that it is a fundamental constant of the Sun — and could potentially be a fundamental constant of other stars.

The findings could, therefore, completely change our current understanding of how magnetic energy is transferred and used in stellar atmospheres.

“The discovery of such a distinctive marker — potentially a new constant of the Sun — is very exciting,” Dr. Morton said.

“We have previously always thought that the magnetic waves were excited by the hydrogen at the surface, but now we have shown that they are excited by these sound waves. This could lead to a new way to examine and classify the behavior of all stars under this unique signature.”

“Now we know the signature is there, we can go looking for it on other stars.”

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Thumbnail image: A Coronal Mass Ejection on our Sun on August 31, 2012. Credit: NASA / SDO / GSFC