Coronal loops are generated by the Sun’s magnetic field
Acoustic waves
Immense coils of hot, electrified gas in the Sun’s atmosphere behave like a musical instrument, scientists say.

These “coronal loops” carry acoustic waves in much the same way that sound is carried through a pipe organ.

Solar explosions called micro-flares generate sound booms which are then propagated along the coronal loops.

“The effect is much like plucking a guitar string,” Professor Robert von Fay-Siebenbuergen told BBC News at the National Astronomy Meeting in Preston.

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http://news.bbc.co.uk/2/hi/science/nature/6574059.stm