Interesting subject as we await a solar storm next week. At https://phys.org/news/2022-01-scientists-mysterious-finger-like-features… … but see also www.nature.com/articles/s41550-021-01570-2 … where we learn that back in 2019, solar scientists noticed mysterious motions within a solar flare. Unlike a mass of bright energy erupting outwards from the Sun, they showed, in one flare, a decreased flow of energy as if plasma was falling back into the Sun. The phenomenon was given a monicker at the time, 'downward moving dark voids.' What was going on? Solar scientists assumed it was something to do with magnetic reconnection events, a hypothetical process. They assumed the dark downflow fingers were a sign of broken magnetic fields 'snapping' back like an elastic band released at one end. Another solar flare, in 2020, revealed the downflows were slower moving – quite unlike the idea of snappiness. Obviously, magnetic reconnection could not be involved, or the theory would have to be drastically altered to make room for the new discovery. The option they chose was that magnetic reconnection was not involved. The downward voids, they say, are caused by a turbulent environment – as a result of two fluids with different densities interacting. The dark voids are, it seems, a plasma free zone.
The bigger news of the week was sent in by Willian – see https://www.yahoo.com/entertainment/7176-bce-sun-erupted-may-140005823.html … in 7176BC the Sun erupted in what may be the biggest flare in the last 10,000 years [the Holocene]. The evidence appears to come from ice cores, although tree rings are also mentioned. What was found in an ice core was beryllium 10 [almost 4 times normal levels], chlorine 36 [6 times normal] and what looks like a big injection into the atmosphere of C14. Was it a solar flare? That is the best candidate, it is thought, although supernovae or a bombardment of cosmic rays from outside the solar system might also be involved. It is also said to have coincided with a solar minimum.
The same story is also at https://phys.org/news/2022-01-ancient-ice-reveals-mysterious-solar.html …