Why is the Sun’s corona so hot? Two words: Solar tornadoes | Ars Technica

http://arstechnica.com/science/2012/...lar-tornadoes/

One of the abiding mysteries surrounding our Sun is understanding how the corona gets so hot. The Sun's surface, which emits almost all the visible light, is about 5800 Kelvins. The surrounding corona rises to over a million K, but the heating process has not been identified. Most solar physicists suspect the process is magnetic, since the strong magnetic fields at the Sun's surface drive much of the solar weather (including sunspots, coronal loops, prominences, and mass ejections). However, the diffuse solar atmosphere is magnetically too quiet on the large scales. The recent discovery of atmospheric "tornadoes"—swirls of gas over a thousand kilometers in diameter above the Sun's surface—may provide a possible answer.

Sam Wormley:
Why is the sun's corona so hot?

Global warming?