Solar flare. Image copyright NASA
Written by Lee Bell
Researchers at Queen’s University Belfast believe they have uncovered some mysteries in how the sun is able to heat its atmosphere.
Published in a study in Nature Physics, the scientists found that magnetic waves crashing through the sun are one of the key ingredients in the heating process and thus propelling the solar wind. The findings come after scientists suggesting for years that these waves may play an important role in maintaining the sun’s super high temperatures, but only now have they been able to prove it.
“For a long time scientists across the globe have predicted that Alfvén waves travel upwards from the solar surface to break in the higher layers, releasing enormous amounts of energy in the form of heat, explained Dr. David Jess from the School of Mathematics and Physics at Queen’s University Belfast.
While researchers had already able to prove that the waves existed, it isn’t until now that they’ve been abkle to present direct evidence that they have the capability to convert their movement into heat.
“At Queen’s, we have now led a team to detect and pinpoint the heat produced by Alfvén waves in a sunspot,” Jess added. “This theory was predicted some 75 years ago but we now have the proof for the very first time. Our research opens up a new window to understanding how this phenomenon could potentially work in other areas such as energy reactors and medical devices.”
To uncover the mystery, the research took advantage of advanced high-resolution observations from the Dunn Solar Telescope in New Mexico, US, alongside complementary observations from NASA’s Solar Dynamics Observatory, to analyse the strongest magnetic fields that appear in sunspots.
“By breaking the sun’s light up into its constituent colours, our international team of researchers were able to examine the behaviour of certain elements from the periodic table within the sun’s atmosphere, including calcium and iron,” added another researcher on the paper, Dr. Samuel Grant from Queen’s University.
“Once these elements had been extracted, intense flashes of light were detected in the image sequences.”
He said that these intense flashes had all the hallmarks of the Alfvén waves converting their energy into shock waves, in a similar way to a supersonic aircraft creating a boom as it exceeds the speed of sound.
“The shock waves then ripple through the surrounding plasma, producing extreme heat. Using supercomputers, we were able to analyse the data and show for the first time in history that the Alfvén waves were capable of increasing plasma temperatures violently above their calm background,” he explained.
Read more at www.v3.co.uk