I saw those last night. I was wondering, but wasn't able to find out -- the videos, are they compressed time? Or 1:1 time? Because the one of the flare is absolutely amazing.
I don't know the duration, but would be surprised if that huge structure lasted more than a few hours (due to the lack of visible rotation of the feature -- the rotational period of the sun is about 27 days as seen from Earth).
The spatial scale is also awe-inspiring. The diameter of the prominence is about 1/6 that of the Sun. The Sun is about 110x the diameter of the Earth. This means 15-20 Earths would fit, end to end, inside the magnetic loop. For another point of comparison, see:
