Cracking 60-year-old mystery of Sun’s magnetic waves

A Queen’s University Belfast scientist has led an international team to the ground-breaking discovery of why the Sun’s magnetic waves strengthen and grow as they emerge from its surface, which could help to solve the mystery of how the corona of the Sun maintains its multi-million degree temperatures.

Dr David Jess from the School of Mathematics and Physics at Queen’s led the team of experts. He explains: “This new understanding of wave motion may help scientists uncover the missing piece in the puzzle of why the outer layers of the Sun are hotter than its surface, despite being further from the heat source.

“By breaking the Sun’s light up into its basic colours, we were able to examine the behaviour of certain elements from the periodic table within its atmosphere, including silicon (formed close to the Sun’s surface), calcium and helium (formed in the chromosphere where the wave amplification is most apparent).

“The variations in the elements allowed the speeds of the Sun’s plasma to be uncovered. The timescales over which they evolve were benchmarked, which allowed the wave frequencies of the Sun to be recorded. This is similar to how a complex musical ensemble is deconstructed into basic notes and frequencies by visualising its musical score.”

The team then used super computers to analyse the data through simulations. They found that the wave amplification process can be attributed to the formation of an ‘acoustic resonator’, where significant changes in temperature between the surface of the Sun and its outer corona create boundaries that are partially reflective and act to trap the waves, allowing them to intensify and dramatically grow in strength.

The experts also found that the thickness of the resonance cavity -the distance between the significant temperature changes — is one of the main factors governing the characteristics of the detected wave motion.

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