With regard to the recent arXiv article:
J. D. Shelton, Eddy Current Model of Ball Lightening
http://arxiv.org/abs/1102.1224
I wonder if this is a reasonable explanation of ball lightening, or if there is such an explanation. The paper is somewhat technical and E&M is one of my worst subjects.
Please feel free to edit this question to one better suited, or if you don't have the rep, add a comment suggesting changes.
Ball lightning could definitely be some atmospheric pressure plasma phenomenon. You can make a pretty impressive ball plasma by discharging a kilojoule-scale capacitor bank into a bucket of salt water. Check out Free-Floating Atmospheric Pressure Ball Plasma. In most of those pictures they're using a copper sulfate solution, but that's not essential (sodium chloride also works). These ones only last a (significant) fraction of a second, but I'm sure if you made a larger one (e.g. by a lightning strike), they could last longer.
BTW, this was the subject of a killer science fair project: http://www.youtube.com/watch?v=SE6sbaNsKoc
It's not a plasma. Couldn't be. When I saw one over a decade ago, it went straight through my glass window (which would insulate a plasmoid). The glass did slow it down to a walking-pace though, which was quite eery. Also, it had a sulfuric smell and was absorbed by my CRT tv, didn't even damage the thing... just turned it off.
From my reading not all descriptions of "ball lightning" could be plasma. Plasma can't last for minutes hovering and/or passing through solid objects.
A free standing ball of plasma for a few seconds in the air sounds pretty reasonable though.
This is a qualitative explanation of plasma behavior in a plasma ball given by the famous theoretical physicist Boris Kadomtsev in his book "Dynamics and Information":
The whole picture, despite its complexity, can be qualitatively easily understood from a physical point of view. Of course, theoretically much easier to imagine absolutely symmetrical glow discharge between the inner and outer electrodes, but such a discharge is unstable: due to the heating of the gas and lowering its local density with a corresponding decrease electrical resistivity it is more profitable to flow through relatively narrow channels - tubes. The discharge breaks down into plasma cords. Being lighter, these cords float up under Archimedes force. And the interaction of cords with gas flows and between themselves leads to the formation of complicatedly organized picture of "snakes", resembling the mythological head of the Gorgon Medusa. One can also understand why the ends of each "snake" form "cat paws". If the conductivity of the electrodes is low, then directly opposite to tht end of discharge tube surface charge density becomes less and the end of the "snake" with opposite charge conveniently split and run from point to point, collecting surface charge.
I think that "magnetophosphenes" like those produced by transcranial magnetic stimulation, are more likely--ie a strong fluctuating magnetic field produced by nearby lightning strikes causes visual hallucination in the occipital cortex (visual region). These are reproducible using TMS but other mechanisms like plasmas are possible. Transcranial stimulability of phosphenes by long lightning electromagnetic pulses Authors: J. Peer, A. Kendl
