I generally find your posts informative, Sol, and often learn a lot from your debunking, but I think that in the case below I'm going to have to disagree with you. (This thread is too long for me to find out what woo from Zeuzzz set ya'll off in the first place, at least this late t'night...)
The woo (which originated in part from each of the three of them) was that magnetic reconnection was impossible because it involves open field lines and therefore violated Maxwell's equations. Here are some examples:
BeAChooser said:
Afterall, mainstream astrophysicists are talking all the time about open field lines. So there must be monopoles all over the universe.
Its a consequence of using the
Real Properties of Electromagnetic Fields and Plasma in the Cosmos, as opposed to the one invented by atrophysicists, ivolving frozeon in magnetic field lines, "open" magnetic fields, magnetic reconnection, etc, or any other new property of magnetism we have
never had
any experimental evidence for.
This second quote, incidentally, makes Zeuzzz' recent claims that he always agreed reconnection exists all the more laughable. But anyway...
To disprove this nonsense, we posted a magnetic field configuration - a standard one involving separator reconnection - which clearly reconnects and has zero divergence. It has a time-varying curl and
does require an interesting volume current density (as I pointed out when we first started discussing it), and so at least for that type of reconnection some kind of stuff has to be around to support that current. But there's no reason it needs to be a plasma.
More recently the "discussion" has focused on the issue of whether reconnection can produce energy. According to Zeuzzz, magnetic field lines don't exist, and so saying that energy is released when they reconnect is nonsensical.
?????? what exactly reconnects? metaphysical lines that dont even exist in reality? your example of a saddle point was clearly a bad one, nothing physical can result from reconnection of metaphysical lines in saddle points, the whole idea that lines that do not physically exist (apart from in the mind of people who use them to model the fields or hills) can cause a huge physical reaction is ludicrous. We are going to have to agree to disagree on this one, as its obvious you will not change your mind, and neither will I.
Of course after saying he would never change his mind he now has (and I'm sure he'll quickly change it again in response to this comment and deny that), but only after several weeks of bludgeoning with cold hard mathematics and facts.
It is trivially true that magnetic fields can store energy and that magnetic fields can reconnect, recombine, really whatever you want to call it, but....
That's what the woos were denying originally, and so the first part of the discussion centered on that. BAC has left the building, Ian is more reasonable, but Zeuzzz (rather than ever admit defeat) has simply shifted, intelligent design-style, to a new and slightly more subtle form of woo. Some remnants of the original discussion remain, as you can see.
There is a technical phenomenon in space plasma physics and plasma physics in general, called Magnetic Reconnection, and this phenomenon is a consequence of the magnetohydrodynamic equations.
I agree that the term is most often used in the context of plasma physics, simply because that's more or less the only context where it's physically interesting. But in the general sense, as you say, it can occur any time you have B field lines reconnecting, and since this discussion began to dispel some woo about violations of Maxwell's equations we've focused on the simplest examples.
In absence of plasma you just have the superposition of different fields. You need the plasma to provide current sheets and magnetic flux ropes and all the other neat phenomena that are tied to the magnetic field lines to create the abrupt change in geometry that happens when Magnetic Reconnection occurs.
Yes, I agree.
There are some large outstanding questions w/r/t magnetic reconnection specifically whether magnetic reconnection or current disruption occurs first when initiating a magnetic substorm in the earth's magnetotail. This should help establish which is the root cause of magnetic substorms. So at the moment it's just two competing explanations, both of which scientists take quite seriously.
Again, agreed. A long time ago I asked Zeuzzz whether the only thing he objected to about reconnection was the quantity of energy released and/or whether it was the correct explanation for various astrophysical phenomena. He said no, but by now has probably changed his mind.
So just to conclude I guess how you feel about this argument all depends on what your definition of "is" is, but I can tell you how space plasma physicists define it. Please,though, try to be polite to each other.
Well, when Zuezzz makes statements like "Real Properties of Electromagnetic Fields and Plasma in the Cosmos, as opposed to the one invented by atrophysicists, ivolving frozeon in magnetic field lines, "open" magnetic fields, magnetic reconnection, etc, or any other new property of magnetism we have
never had
any experimental evidence for" it's hardly just a difference of opinion or semantics. As for being polite, it's too late for that....
which was what I was continually asking you to explain, and you still have not. Not once have you mentioned what gains the energy and how, what MHD terms you are using, or any other factors involved. I never disputed that by using maxwells equations you can model the change in topology of field lines around a neutral point, like you did.
sounds like another new property of magnetism that only applies in space, or to other purely theoretical models like 