Apologies for resurrecting this ancient thread, but Jean Tate suggested we might start a new one regarding comments that were a bit OT in the Electric Comet thread.
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So, having done a bit more research now, here is what I take from the EU misunderstandings related to magnetic reconnection:
First off, let's go back to 1976. Alfvén authors the paper:
On Frozen-In Field Lines and Field-Line Reconnection
http://onlinelibrary.wiley.com/doi/10.1029/JA081i022p04019/full (paywalled)
In that paper he rails against the inappropriate use of the frozen-in concept, and therefore its extension to field line reconnection.
This has been covered by many others before me, who have far greater knowledge in the field. As far as I can make out, he is (rightly) saying that this field line reconnection cannot happen in an ideal MHD scenario. Nobody these days is saying it can, so this is pretty much moot. However, he also says in that paper:
In case the magnetic field varies with time, the geometry near neutral points may change in such a way that it is legitimate to speak of a 'field-line reconnection' We cannot exclude the possibility that some of the field-line reconnection formalism may be applicable, but this remains to be proved.
So, this is quite obviously Alfvén saying that he is not throwing it out entirely, and there may be situations in which it is valid.
Then he goes off on a rant in a conference speech in 1986, saying pretty much the same thing, and calling it pseudoscience:
Double layers and circuits in astrophysics
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19870005703.pdf
However, from a 1987 paper:
Viking in the plasma universe
http://onlinelibrary.wiley.com/doi/10.1029/GL014i004p00475/full
http://www.imagebam.com/image/26c07e531125370
.....he produces a table (imagebam link above) that states that 'Energy release through magnetic merging' in a 'Fluid plasma' is 'possible'. So that would appear to say that his statement from 1976, above, still holds. Now, he knows that it cannot happen in an ideal MHD situation, so what is he saying here? Well, to my mind, it is obvious that he realises that there may be non-ideal MHD situations where it is possible. This would not be at all surprising, given the stance taken by his collaborator Carl-Gunne Falthammar.
Falthammar was a co-author of Alfvén's, and may have been a student of his(?). It is obvious that they worked together closely, and were of a similar mind.
Now, if we go back in time again, to 1979, we find Falthammar as a co-author on a paper in which it was claimed by the authors that:
Both the large scale average electric field and the fine scale field observed during a magnetopause crossing show the existence of significant tangential electric field components on both sides of the magnetopause, in agreement with the requirements of reconnection theories
.
Direct observation of a tangential electric field component at the magnetopause
F. S. Mozer, R. B. Torbert, U. V. Fahleson, C.-G. Fälthammar, A. Gonfalone, A. Pedersen, C. T. Russell (1979)
http://onlinelibrary.wiley.com/doi/10.1029/GL006i004p00305/full
More on the lead author, F.S. Mozer, later.
So we know that Falthammar, whilst still closely collaborating with Alfvén, is open to magnetic reconnection as at least a possibility. Alfvén and Falthammar, for example, were co-authors, in 1978:
On the significance of magnetospheric research for progress in astrophysics
http://www.spp.ee.kth.se/publications/pdfs/TRITA-EPP-78-07.pdf
And then we move forward in time again, to Falthammar in 2007 (co-authored with the previously mentioned F. S. Mozer):
On the Concept of Moving Magnetic Field Lines
http://onlinelibrary.wiley.com/doi/10.1029/2007EO150002/pdf
Now, this is essentially a comment on a paper that Falthammar feels is somewhat in error. The main thing to take away from it, however, is where he says:
In fact, the most interesting plasma physics occurs precisely where and because this equation is not satisfied, such as the auroral acceleration region, magnetic field reconnection, turbulence, shocks, and many wave modes
.
He further fleshes this out by saying:
The nonexistence of parallel electric fields was later challenged by Alfven, who suggested that auroral primary electrons may gain their energy from falling through a parallel potential drop above the ionosphere and described how parallel electric fields can 'cut' magnetic field lines. Alfven's idea was contrary to contemporary beliefs and was almost universally disregarded, but when in situ measurements in space became possible, they brought the first indications that Alfven might be right. Since then, an overwhelming amount of empirical data have proven that magnetic field aligned electric fields exist and are of key importance in the physics of auroras [Falthammar,2004], in magnetic field reconnection [Mozer,2005], in shocks [Mozer et al,2006],and in plasma turbulance and many wave modes
.
So, it is obvious that Falthammar, by 2007 at the latest, has been converted to the dark side. But, hold on; what is he saying in this second quote? First of all, he's got Alfvén suggesting that non-existent field lines can be 'cut'! Strange that they can be 'cut', but cannot reconnect. What are they then doing? Just wafting around in the breeze? Who knows? Read on. And then he goes on to say that poor old Hannes was disregarded by contemporary scientists, and that he then turned out to be right. Happy days. And then good old Alfie's brilliant suggestion about magnetic field aligned electric fields is now a key factor in such things as, !tada!, magnetic field reconnection! Brilliant. So the whole concept of MRx is, yes you heard it here first folks, due to Alfvén! Well, at least that's the spin that Carl-Gunne puts on it. And who are we (or anybody else) to argue with him? Tusenfem might, but last I heard he was playing an Ork somewhere in the Tyrol.
Lest there be any doubt that Falthammar has has come over to the 'pseudoscience' of MRx, he makes comments on it and even has a small section on it, in a presentation from 2010:
The Earth’s Magnetosphere as a Key to the Plasma Universe
http://www.diva-portal.org/smash/get/diva2:484042/FULLTEXT01.pdf
In this, he comments:
......Alfvén waves appear to be responsible for certain kinds of auroras (Stasiewics et al., 2000; Keiling et al. 2003; Chaston et al. 2003, 2007; Janhunen et al., 2006), and recent observations (Chaston et al., 2009) indicate that they play an important role in magnetic reconnection
.
Alfvén responsible again, albeit tangentially. He also references Priest & Forbes, 2000, which, from memory, was oft referenced by Tim Thompson in his seemingly interminable battle against pseudoscience.
So, having established that Falthammar was a proponent of MRx, and that it was all down to Alfvén's idea anyway, what did he believe was happening in this MRx? Well, he references, and co-authors with F. S. Mozer in the 'On the Concept of Moving Magnetic Field Lines' paper, above. So just to clear up any confusion about what they are talking about, this is the paper that is referenced:
Criteria for and statistics of electron diffusion regions associated with subsolar magnetic field reconnection
F. S. Mozer
http://onlinelibrary.wiley.com/doi/10.1029/2005JA011258/full
And Mozer says:
One result of this understanding is that the tangential current required to change the direction of the reconnection magnetic field is parallel to the tangential electric field that is required for an E x B/B2 drift of plasma and field lines into the reconnection region such that there is a significant j.E over the ion skin depth region to convert magnetic field energy to ion energy over a large scale. However, on this scale, magnetic field lines still move with the E x B/B2 velocity, so the physics in the electron diffusion region on the electron skin depth scale, c/wpe (5 km at the subsolar magnetopause), must be considered in order to understand magnetic field reconnection.
So, nothing about circuit reconnection here, nor current reconnection. Just good old MRx. However, the 'consideration' that he puts at the end of that quote is beyond my pay grade, but doesn't appear to hold any great hope for MRx haters.
So, to summarise;
MRx is all Alfvén's fault. He led poor old Carl-Gunne astray as well. Not to mention a shed load of other scientists, including those on this board. However, the EU people think he's wrong. Hey ho. Either that or they don't know what they think, because they don't understand what he was saying, and/or didn't bother to do any research to find out.
Feel free to comment, otherwise we can let this ageing thread return to its well earned retirement, safe in the knowledge that MRx is proven beyond any doubt.
