Astronomy Picture of the Day: Why the sun's corona reaches temperatures of several million degrees Celsius

 

Why the sun's corona reaches temperatures of several million degrees Celsius is one of the great mysteries of solar physics. A "hot" trail to explain this effect leads to a region of the solar atmosphere just below the corona, where sound waves and certain plasma waves travel at the same speed. In an experiment using the molten alkali metal rubidium and pulsed high magnetic fields, a team from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), a German national lab, has developed a laboratory model, and for the first time experimentally confirmed the theoretically predicted behavior of these plasma waves—so-called Alfvén waves—as the researchers report in the journal Physical Review Letters.

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https://phys.org/news/2022-01-liquid-metal-insight-mechanism-sun-corona.html