195Å, FLASH movie and
H-alpha GIF movie  compared

The dark inverted V on the H-alpha sequence was not present before the flare. Gema Araujo writes by email. "I don't know but I am sure (almost to 100 %) that the filament wasn't here before flare. If I had seen a filament there I would have recorded that section."

Comparing the two movies, the V seems to be where the tsunami splits in two either side of a bright spot on the 195Å sequence. The spot acts like an island in the path of a tidal wave. What is an "island" doing in the gas of the solar corona?

My tentative explanation follows. Of course the corona is not simply gas, but is ionised plasma, and the electrically charged plasma could be bound into a strong structure by a powerful, localised, magnetic field. The bright "island" could be acting like a pore does in the photosphere: a spot where magnetic field lines emerge but are not yet extensive enough to produce a sunspot. Or a facula, where concentrated magnetic flux tubes re-enter the sun, after curving over from an adjacent sunspot.

The inverted V seems to drift back towards the solar flare. Rather how the plasma of the tsunami swirls down and back on the 195Å sequence, behaving like a sea wave running up a beach and back. Is the V a "splash" up into the high corona caused by the tsunami hitting a strong magnetic column?

See page 1 for my "explanation" of how the tsunami began. The H alpha sequence throws my explanation into some confusion I must confess.

Jan Janssens 
Friday, December 28, 2007 1:24 PM

John, Gema,

Thanks for the incredible images and image processing! John, you have a great site on this topic! What I think is happening is that due to the magnetic configuration at the flare's site, the southern part of the filament is ejected on a southly directed, "surface-grazing" trajectory. So I don't think this is a Moreton wave or a tsunami or a CME, because it is very directed and not ejected into space. Maybe it's an EIT-wave (from your definition). I would like to point out that there is another bright spot, to the lower right of the other bright spot and more south of the active region. I think they have both the same magnetic polarity (otherwise we would see a -faint- filament between these points), and thus are part of the same magnetic region. What could be happening here is that the embedded magnetic field in the ejected cloud is crashing in on this unipolar magnetic wall. It seems like the speed and the field of this cloud bend this wall backwards, much like a professional gymnastics, standing initially erect, can bend backwards until she touches the surface with her hands. So then you have magnetic fields coming out of the solar surface (her feet), and going back into the surface (her hands). Because you have now a bipolar magnetic field, a filament will form ("under her back"). It also explain why you have a filament, and not a "dot" as would be the case with just one bright point /magnetic island. Most of the ejected material is then moving over and aside (right, west) of this filament. When most of the high speed material has passed, the apparently still intact filament is then moving back (to the north) to its original position between the bright points. Just thinking out loud here, there may be other theories as well. Again my congratulations for all the great imagery!

Jan Janssens  ( SOLAEMON)

http://users.telenet.be/j.janssens/Engwelcome.html

Howard Eskildsen
Jan 1, 2008 5:42 am

Thanks for the images and discussion, Jan, Gema and John. Most interesting piece that I have seen on the sun in a long time.
Howard