High-resolution images show that the solar corona is filled with large, banana-shaped magnetic structures called coronal loops. It is thought that these coronal loops, some over a few 100,000 km long, play a fundamental role in governing the physics of the corona and are even responsible for huge atmospheric explosions that occur in the atmosphere, what we call solar flares.
These giant magnetic loops have also been observed to undergo periodic (oscillatory) motion, which can be thought of as someone plucking a guitar string (transversal oscillations) or blowing the wind-pipe instrument (longitudinal oscillations). With the length and thickness of the string fixed, the pitch of the note is determined by the tension of the string and the tone is made up of the harmonics of the modes of oscillation.
These musical sounds created by longitudinal vibrations in the Sun's atmosphere have been recorded and accurately studied for the first time at the University of Sheffield using mathematical theory combined with the satellite observations. The solar physicists captured the music on tape and revealed the harmonious sounds are caused by the movement of giant magnetic loops in the solar corona - the outermost, mysterious, and least understood layer of the Suns atmosphere. Most interestingly, the team studied how this sound is decaying, giving an unprecedented insight into the physics of the solar corona.
Video from the Transitional Region and Coronal Explorer, showing eruptions from the solar corona. Credit: TRACE
In this sense, the solar atmosphere is constantly pervaded by the music of the coronal loops. The coronal music also provides scientists with a unique and unprecedented tool to study the magnetic solar atmosphere, as the motion of these loops is determined by their local surroundings. This technique is known as solar magneto-seismology and is very similar to the seismology methods used by geologists studying earthquakes.
Studying this magnetic solar atmosphere will help make further breakthroughs into understanding one of the key and central unresolved problems of modern astrophysics, such as the heating of solar and stellar coronal plasmas and revealing the underlying physical processes.
Are there millions of localized magnetic explosions releasing the energy necessary to maintain the corona at millions of degrees or is the physics related to the numerous waves propagating from the internal regions of the Sun toward its outer regions, reaching even space around the Earth's atmosphere?
Universal Transversal Oscillations - Music From The Sun