Laser-blasted plasma shows how instabilities could heat the sun's corona
From its visible surface, the sun radiates heat at a relatively cool temperature of 5,800 Kelvin. Yet within the thin outer layer of the sun's atmosphere known as the corona, electrons can reach temperatures of millions of degrees, for reasons astronomers have yet to fully explain.
We haven't written up this one. Phys.org has the full story — the link below goes straight to it.