Hi Blueshift,

I don't mean to say that math is unimportant, it is after all the language of science. But it is something completely different when math is used exclusively to argue something that will later be observed. I regularly check the Arxive:astro-ph papers to see if something interesting can be found (usually Antoniseb beats me to it, so I could probably just relax and wait for his posts). There's always a fair number of papers who "solve" equations and try to predict what it means for cosmology. I think that those papers are extremely speculative, the people producing them are probably brilliant scientists, too smart for me that's for sure, but it is not something I can relate to, I need solid (preferably visble) evidence.

Cheers.

Tim,

I forgot to thank you for the link to the electric/currents publications, there's much more than I thought, it is a nice overview.

Cheers.

Ah, verily I say unto Brother V, get thee into the real world, and learn thou there real physics, for then shall the Kingdom & the Glory be thine. But ware the day when thy shalt speak with conviction on that which thou knowest not, for on that day the Gods shall surely be offended, the sky darken, and thunderbolts from the Gods shall be thy reward!

Therefore do I suggest a little light reading ...

Magnetic Reconnection : MHD Theory and Applications, by Eric Priest & Terry Forbes, Cambridge University Press, 2000. This book covers both the mathematical theory, as well as laboratory applications. Expensive, but written by leaders in the field. I have this one on my own book shelf. It includes astrophysical & magnetospheric applications.

Magnetic Reconnection in Plasmas (Cambridge Monographs on Plasma Physics), Dieter Biskamp, et al. (editors). Cambridge University Press, 2000. I don't have this one myself (yet). It deals less with astrophysics than does the previous book, but it includes an expanded discussion of the microphysics of reconnection, and is perhaps much more directed towards laboratory applications of plasma physics.

The Physics of Plasmas, T.J.M. Boyd & J.J. Sanderson, Cambridge University Press, 2003. This is another one that I have on my own bookshelf. It deals less specifically with reconnection, though it certainly is covered, and is a much more general work on plasma physics than either of the previous books. It deals specifically with the difference between ideal & resistive MHD, and includes the classical theory of plasmas. And in paperback, it's a lot cheaper than the other two.

Plasma Astrophysics, Toshiki Tajima & Kazunari Shibata, Westview Press, 2002 (the Advanced Book Program from Perseus Press, which used to be part of Addison Wesley). I have this one too. As the title suggests, this book deals with the astrophysical applications; it includes chapters on magnetic reconnection & cosmological plasma astrophysics (the way it is really done). One of my personal favorites.

Space Physics: An Introduction to Plasmas and Particles in the Heliosphere and Magnetospheres, May-Britt Kallenrode, Springer-Verlag, 2001 (2nd ed). I have this one too. it is more narrowly focused than Tajima & Shibata, dealing exclusively with plasma physics in the solar system. So, it deals with MHD & magnetic reconnection as applied to planetary magnetospheres, the solar wind & heliosphere.

Now, there are quite a few journal review papers & the like, but they are not much use, since they routinely presume that the reader already knows a good deal about the relevant physics. Better to start with the basics. Of course, these are all real physics books, and one does have to understand mathematics at a fairly high level to get the most out of them. But, that's plasma physics for you.

Oh, and magnetic field lines certainly do cross. Period.

Now, lets see here ...

Always ready to be helpful, you know. There's nothing quite like the NASA Astrophysics Data System for finding what's out there. It's maybe not 100% complete, but it's pretty close, and goes way back into the 1800's. Select "Search References", and when you get there, select "Astronomy and Astrophysics". Aside from what we already have, the key phrases to search for are things like "neutral current", "current sheet", and of course, "magnetic reconnection". You can chose broader searches like "Space plasma" and the like. And make sure you check the "and" button on searches, or you'll get 10,000 responses to everything. For the older papers, you can usually download a PDF directly.


Actually I did mean it at the time, but I'll allow that I may be going off the deep end there. I'm sure there are valid scientific pursuits, like biological species classification, where math is perhaps less zealously involved. But the statement certainly holds true for plasma physics, where it is almost impossible to understand anything independent of its mathematical description. It's not as bad as quantum mechanics, which is incomprehensible outside of its mathematical formalism, but it's not far off.

I don't think the specific case can be so easily generalized. Theories are, of course, necessarily calibrated against observation. But theory can just as easily anticipate observation. A prime example is Einstein's conclusion that light would be deflected in a gravitational field, which had no observational basis at all. It was pure mathematics, pure guess work on Al's part, and it paid off handsomely in a truly unexpected observation. Another good example is the mysterious Heisenberg uncertainly principle in quantum mechanics. Undoubtedly a real part of the physical world, it can be derived from mathematics without the involvement of physics at all, from Fourier theory. In the latter case, especially, a fundamental principle of physics is derived without the intervention of physics! The connection between mathematics & physics is far more profound than most people think.

Now I surely hope we don't wind up in some repetitive mode where "magnetic field lines cross" and "magnetic field lines can't cross" bounce back and forth ad-infinitum. I am only too happy to confess that there are plenty of other people in the world who know more physics than I do, but I'm not quite past the age of senescence yet, and I actually do remember some of my graduate E&M courses. I think I'm a reasonable judge of what magnetic field lines will & won't do, under most circumstances, and verily I say unto you that they cross. Behold ...

Hi Tim,

And again you're throwing the whole encyclopedia of plasma physics at my head (it's getting bigger though).
I'm not arguing that magnetic reconnection in itself is not well studied and extensively described. I'm only arguing that the basic idea is flawed and all the rest is confirmation of the basic idea. I'll not continue the yes/no game, let's leave it at "what if", after all I hope I clarified the position of the EU model on reconnection. So, what if the EU claim that reconnection is in actuality a discharge phenomenon is true, wouldn't it change the way we look at plasmas?

Thanks for the library link, the ones I check are not as extensive.

Cheers.

Here's an interesting easy-to-read paper about a much more detailed look at the magnetism on the solar surface. It finds that there is a great deal more magnetic energy at the surface than previous models indicated.

A substantial amount of hidden magnetic energy in the quiet Sun

Note that this paper does not support the Electric Universe model as such, but it does give more details about the observed electro-magnetic nature of the sun and the corona than was previously available. I would be interested in reading how the proponents of the Electric Universe account for what's written here.

__________________
Forming opinions as we speak

Hi Antoniseb,

I already read the paper and it's about the magnetic field of the "quiet Sun", I didn't understand the conclusion that is present at the solar surface, but if that is real, it could mean something for the EU model.
Although at this point I guess that the magnetic field strength from the "standard view" can probably be modelled to allow for this observation.

Cheers.

This is from the article in Story Comments about the puzzle of what makes the corona so much hotter than the solar surface (see news section)

If waves heat the corona like waves crashing on a beach, what constitutes the beach in case of the corona? There has to be something to crash into, as far as I can tell the corona is a relatively low-density plasma.


Well, that directly relates to the discussion about reconnection; in the standard view reconnection explosively releases the energy (produced somewhere deep inside the Sun) stored in the loops. In the EU view the loops are caused by a vast electric circuit (connected to the galactic Birkeland currents) that releases, through discharge, more energy than is stored in the loops, exactly because of the connection with the vast energy source of the Birkeland currents.

There is another piece to this puzzle: the Sun's surface is about 6000 Kelvin, in sunspots we can see deeper into the Sun and the temperature there is lower by 1000 K. So we have a lower temperature deeper down into the Sun and at the same time a hotter corona further out.
The magnetic field is the usual suspect, and again in this whole article there is no mention of the electric currents (see Tim, currents are way down the list).

Cheers.

That doesn't make sense to me VanderL. There is no need for a wave to crash into something solid to heat up--you see that occurring in supernova shock-wave fronts all the time. The low-denisty ISM is certainly less dense than the plasma making up the sun's corona.

I believe Tim has already shown pretty convincing evidence that there is no such circuit, vast or otherwise. A circuit requires two way flow, the sun's flow is only outward.

__________________
All civilizations become either spacefaring or extinct.~ Carl Sagan ~

Humanity must rise above the Earth, to the top of the atmosphere and beyond, for only then will we fully understand the world in which we live.~Socrates, 500 B.C. ~

Let every man judge according to his own standards, by what he has himself read, not by what others tell him. ~Albert Einstein~

Hi VanderL,

If something fundamental is wrong with physics that would knock over the whole
apple cart, I would think it would be in something more basic like Kepler's Laws..

Your explanation for why things are round doesn't seem to cut it..The standard model does a better job, offering a simpler explanation that makes more sense.

How do you account for tidal forces? I don't see how electrical forces can explain
that..The ocean should be over whelmed by the Sun and Earth in the EU model.
How can a charge just 1/6 of the Earth affect water without polarizing all of it?
Shouldn't compasses be effected by this?
Or, do you see Kirschoff's laws going to work here between the Earth and the Moon but failing to do so with an electric Sun? Maybe I'm just ignorant about
something here and you have some particular charge potentials for each body
to explain this?

Further, I would think that the crises that Rutherford's view of a solar system
model of the atom would face the EU model as well....An electrical Earth should
lose energy and spiral right into the Sun, attracted to its different potential..The returning current should hoist us along for a final sling inward..

Somehow, I just don't see it...You need to place a precise location for the return current...The only possible place would be at the winter solstice...The trouble with
that would be that we would need a Sun that doesn't spin..



blueshift

OK, you're losing me here BigGuy. If the basic idea has been well studied, extensively described, and "confirmed", how can it be so obviously "flawed"?? My whole point in making extensive references to the literature on plasma physics is to show that both mathematics & experience confirm the physics of magnetic reconnection.

Now I'll grant that data have to be interpreted, but the interpretation & the data have to go together. Of course, if the EU claim were true, then it would certainly change the way we look at plasmas, at least in the intellectual sense. But how can you have a "discharge", when there is quite literally nothing there to discharge?

That's my point about harping back to laboratory observations of reconnection in real plasmas. The only way to get a "discharge" is to separate charges, and then let go of them. You can discharge a plasma double layer because it is a charge over-density, a region where charges have been separated. There are no such regions in the middle of a hot neutral plasma, and even if there could be such a thing under some extraordinary circumstance, it would stand out like the proverbial sore thumb. So the phenomena observed in the middle of a plasma simply could not be discharge related, as there is literally nothing to do the discharging!

The same thing holds true for comets. In order for cometary phenomena to be discharge related, somthing has to be more charged up than something else. The solar wind isn't "charged up" at all, it's charge neutral. In order for the comet to have charge, it's got to get charge from somewhere. It's not going to get it from the solar wind, because it would hand off as much - as +, so where does the charge come from? And if it had all that charge, then why doesn't it have a big electric field or a strong electric potential? If the comet had a net charge, then the comet would be surrounded by the alleged double layer. But we know it's not, because we can see the stuff around the comet (and have flown through the stuff with more than one spacecraft), and we can see that it is charge neutral. No charge over density means no double layer means no discharge means the EU hypothesis and observation are not compatible with one another.

The big bottom line is that I already have explored the question you ask: "What if ...". I don't need to explore the answer to that question, because I already know that the EU hypothesis is not true. I know because it has been tested against the real world of observation and it has failed. It's just that simple.

Well, it's a journal paper about magnetic fields, and electric currents aren't the point. If you want electric currents, here are 75 references in the title field. The abstract field returns 178263 references, a list obviously contaminated by noise.

The magnetic field is an obvious "suspect" for the low temperature in a sunspot, for the obvious reason that all sunspots always have magnetic fields that are far stronger than the surrounding fields. But the explanation is not too mysterious, I think. Magnetic fields inhibit convetion, which is how the heat energy gets to the surface. So, in a sunspot, when the heat energy is radiated away, it is not replaced as quickly by heat energy convecting from below. So, the equilibrium condition between convection & radiation is established at a lower temperature. Not too weird.

As for the corona, the heating mechanism remains a matter of some debate, but not for the reason you may think. There are in fact so many ways to heat the corona, that the real problem is figuring which are the most important. Heating by magnetic waves is a fairly stratight forward idea , but full of complications. Despite the reference to waves breaking, magneic waves don't need to break to accelerate partlcles to high velocity. The moving field does that just fine.

Of course, there are also zillions of books & papers on all of this too, but maybe I've already overdone that. But look at the August 2004 issue of Astronomy and Geophysics, which used to be the Quarterly Journal of the Royal Astronomical Society (you can't read it online). It's all about the sun, and has some very good general papers in it that anyone should be able to read, with cool graphics. There is one about sunspot structure, and another about heating the corona.

Science marches on ...

I'll be gone for a few days, but I promise to respond after that,

Cheers.

I've been out for a few days too. This is moving weekend for me.

__________________
Forming opinions as we speak

Hi Tim,

As promised my response.
The point I tried to make about reconnection is still valid, reconnection is just a misnomer for a process that involves several observed features of plasmas. Double layers, quasi neutral plasma (just like the "solar wind"), electric fields (charge separation is not that difficult, and for it to be significant all you need is a "imperfect" plasma) magnetic fields and the notion that magnetic field lines do not cross. The data won't change (a sudden release of energy), only the way it is interpreted.

Charge buildup is exactly what is happening everywhere in space, it doesn't stick out like the proverbial sore thumb because plasma organizes into double layers where the real charge difference shows itself in a small region. Exceed the limit of the plasma in question (whether we talk about comets, solar corona, Io's environment, upper ionosphere (sprites, elves), lightning anywhere, aurorae or Martian dust devils) and a discharge occurs. All these phenomena are visible and happen all the time, every time the effects are different because the local plasma is different in all these places. The input comes from the Birkeland currents where enough energy is available (size indeed matters) to make everything happen. No mysteries there.

The literature really mostly talks about magnetic effect, while we all know that magnetic fields without electric currents is impossible. We only need to see the electric input and everything follows.

So where are the currents that explain these magnetic fields in the first place, if magnetic field inhibit convection as you state why isn't a sunspot hotter than it's surroundings; isn't the magnetic field in sunspots stronger than elsewhere, trapping the energy?

Cheers.

Hi Tim,

Here is a paper that shows what I mean about "magnetism without electricity", Origin and Evolution of Cosmic Magnetism, in the article there is no mention of charge, electricity and "current density" is mentioned only once, all the other "currents" are of the "current/currently" type.
Btw the paper itself is interesting and it shows what is currently known about magnetism in the intergalactic medium and in which area's the Square Kilometer Array can produce new insights.

Cheers.

There were quite a few papers today about the SKA. I was amazed at the number of new areas that it is believed that this array can provide insight.

Concerning the idea that there could be magnetic fields that were born with the universe without related currents, this is something I've never contemplated. It is an interesting idea, and the notion that we might soon be able to show that such a thing existed is astounding.

__________________
Forming opinions as we speak

Hi Antoniseb,

Well, it follows logically from the notion that magnetic fields can be "frozen" in a plasma and carried away in the solar/stellar wind. Of course that doesn't mean it is true, just that it is current wisdom.

I hope the SKA can also shed some light on the magnetic properties of filaments in space aka Birkeland currents.

Cheers.

If the SKA is as successful as the papers today all predict it will be in revealing new aspects of the universe, I hope they can make a good case for building the 100SKA in the near future.

Cranking out those small dishes and linking them up in that kind of quantity should benefit from mass production.

__________________
Forming opinions as we speak

Hi Antoniseb,

There is an enormous number of papers on the SKA at the moment, even today there was a new paper. It seems we have to do all of astronomy over with SKA if we have to believe the authors, it seems as if all questions will finally be answered.

Cheers.

I expect that the deluge of papers about what the SKA could do will finish up soon. Sometimes you see something like this as a big project is requesting funding, or needing some other kind of support.

It may also be that there was some September deadline for competitive proposals on what to do with it, and these are those.

On the other hand, it offers a ten-fold [or more] increase in the signal strength and resolution of the 300 meter Arecibo dish in Peurto Rico, which is currently the biggest, and every time we've had a ten-fold increase like that something new was possible to observe, so perhaps it's not unrealistic.

__________________
Forming opinions as we speak

From the lotus position, in a monotone voice, repeat after me ...

Ommmmmmmmmmmmmmmmplasmadoublelayerdischarge
Ommmmmmmmmmmmmmmmplasmadoublelayerdischarge
Ommmmmmmmmmmmmmmmplasmadoublelayerdischarge
Ommmmmmmmmmmmmmmmplasmadoublelayerdischarge

We have left the realm of science behind, and are now exploring that strange twilight zone, where the mysterious plasma doiuble layer is invisible, even in the presence of instruments that are specifically designed to see it! Why didn't I think of that?

Now, as I already said, at least once before: "The data are magnetic field measurements made by a network of probes in the plasma, measuring the magnetic field as a function of time, amongst other things. It is of no consequence whether or not the plsma double layers were in the minds of the researchers. The reason the point is irrelevant is that plasma double layers are observable, measurable things. They are either there, or they are not, and the data will tell you loud & clear. They were not there, nor would one expect them to be there, since there is nothing to "layer" around. The experiment was designed to measure the magnetic fields in the plasma, and it did. As the magnetic field reconnected, it was observed to do so. There simply isn't any other explanation."

You just keep overlooking the fact that the data consists of direct measurements of the magnetic field & plasma. Those data most certainly would change, and by a huge margin. This is not at all a case of simply changing the interpretation. It is a case of classic science, a test to determine which is the best hypothesis or theory. The EU hypothesis fails the direct test: there are no plasma double layers where the EU hypothesis says they should be. The standard theory passes the direct test: the magnetic field is observed to re-orient itself as predicted by the MHD theory & magnetic reconnection.

If you're going to make claims about the data, you really should have a care to know what the data are first, it's a lot easier that way. In the Swarthmore Spheromak Experiment they had an array of 600 sensors in their plasma, and in the Princeton Magnetic Reconnection Experiment there was a similar, though smaller array of sensors. I have already referenced the published papers describing their research. I did that so you might at least read the abstracts, and thus know what the real deal is.

Well, since when did MHD theory have anything to do with "magnetism without electricity"? MHD theory is all about generating magnetic fields with electric currents, did you not know that? It's pretty basic. The paper is interesting, but the title is a tad misleading. The real thrust of the paper is the observational capabilities of the Square Kilometer Array, and so it says very little about the physics of generating magnetic fields.

Primordial magnetic fields can be generated by turbulence in the dense plasma in the early universe, at or before the era of recombination, or by phase transitions in the early universe, at the time of inflation. This topic is well reviewed in Magnetic fields in the early universe, Dario Grasso & Hector R. Rubinstein, Physics Reports 348: 163-266 (2001).

Primordial magnetic fields can be generated with out electricity, in the classical sense at least, because they are generated by a failure of conformal invariance in Maxwell's equations. But that only works during inflation, before the phase transition that sets E&M off on the classical road. Once that happens, the "no electric current" trick doesn't work anymore. But if you generate even a very weak field that way, it can act as a seed field that is amplified greatly by turbulence in the dense plasma, as I mentioned above.

Clearly, the fates don't want you to see this. It's my third try; the first time my computer crashed, destroying Netscape in the process, and the 2nd time our network crashed. But, as they say, the third time is the charm.

Hi Tim.

Thanks again for the wealth of information, I couldn't find where you got the number of 600 probes of the array of the Swarthmore experiments though, maybe it's somewhere else in the description of the experiment.

You make it seem as if the experiments and the reconnection process are thoroughly understood processes, while the authors claim that the physical mechanism of breaking and reconnecting of magnetic field lines are still unknown.

The setup of the experiments is not to show double layers at all, as a matter of fact the 2 plasmas are toroidal which makes double layer detection impossible. These are not the circumstances found in space, this is modelling (approximations) and the data are then used to model further in a Cray computer, which could take it even further from reality. If we want to show double layers we should send our probes to the most likely places. And double layers are not from the realm of the mysterious twilight zone, they are real!


From the Gaensler, Beck, Ferretti article:
"Magnetism is one of the four fundamental forces. However, the origin of magnetic fields in stars, galaxies and clusters is an open problem in astrophysics and fundamental physics. When and how were the first fields generated? Are present-day magnetic fields a result of dynamo action, or do they represent persistent primordial magnetism? What role do magnetic fields play in turbulence, cosmic ray acceleration and galaxy formation?"

Where did the MHD come in? I don't think they even mention Magneto Hydro Dynamics, did I refer to the correct article?

Now that is really saying that we really don't know anything about what really happened, how can this ever be verified? Inflation is pure speculation, or well, it is at least untestable.

Sorry about the computer crashes, maybe the Gods of Electric Powers were trying to send you a message?

Cheers.

There are two mistakes here. First, it is one thing to see that something has happened, and quite another to know why it happened. My foremost point is that we see magnetic reconnection happen in real time, in the data. Even if it were true that the "why" of it all were a total mystery, that would not detract from the fact that it was seen to happen. Second, the authors are simply stating the obvious fact that there is always something unknown about everything, magnetic reconnection included. The basic theory is indeed well known, as anyone can easily verify by looking at any of the text reference books I have suggested. But the details of practical applications in complex environments are not all well known, and that was the authors' point. Remember, these are professional journal, papers written for an audience already well versed in plasma physics, and certainly not for general readers. So you won't necessarily understand the text as a professional would.

Impossible?? Why do you say that??

Well, that's what I would say, but so far you have disagreed rather strongly with this, by a constant insistance that double layers are not visible. So I assume you think they are magic. If you don't, then what's the point of the discussion?

Well, you are the one who said something about "magnetism without electricity", so I assume you think that I think, or that standard theory "thinks", that magnetic fields are created without electric currents. I just wanted to point out that, with the cosmological exception treated below, that is not the case. So what was your point?

There is indeed a great deal of speculation here, but I only want to show that there is valid physical reason to support the claim that magnetic fields can be generated, without electric currents, in the intense environment of the early universe. The inflation hypothesis most certainly is testable, and is being tested even as we speak, but that is another long thread.

I stand by my earlier claim unphased. There are no plasma double layers, we can see that there are no plasma double layers, and whether or not the magnetic field is toroidal is irrelevant.

Hi Tim,

Sorry for the delayed response, discussing is fun, it just takes a lot more time than I really have.

I didn't claim that the experiment is not giving results, I was (and am) claiming that the data must be interpreted, and interpretations are where models play their role. Seeing magnetic reconnection is the result of formulating what the data mean, based on existing models (something that could on a later date be proven different).
And your second point is partly true, the extent of uncertainty is not stated and this means that the authors are careful to avoid "overstatements" which is a good thing and should be practised by more people. If I claim that the bright spots on comet Wild 2 is proof of an Electric Universe model, I am clearly overstating. If I claim the bright spots support an EU model, I am a bit more careful (although it could be true).

About the experimental setup and double layers, I repeat: we should probe the places where double layers are thought to exist.

QUOTE
VanderL: And double layers are not from the realm of the mysterious twilight zone, they are real!


No I wasn't disagreeing on double layers, "only" magnetic reconnection" or more specifically the part where it is thought that magnetic field lines can cross and reconnect. And the part where magnetic fields can be "frozen in".



My point (which you disagreed with) was that while magnetic fields are widely discussed and used in astronomy, the electric currents responsible for the fields are mostly ignored, or seen as secondary effects. That's why i linked to the articles. The EU model states that the electric fields are the important feature, the magnetic field is secundary.

All true to a certain point, but assuming magnetic fields can exist without electric currents is farfetched imo, but that could be part of the same long thread we don't want to go into.

Cheers.

Perhaps we can proceed in a more organized fashion. So ...

Ok, you assert that the theories of magnetic reconnection and frozen flux are both wrong.

I assert that the theory of magnetic reconnection is correct. As a justification for that assertion, I point to the large body of physics which shows the theory to be valid. I have referenced the sources before, but will do so again, at least in an abbreviated manner, for the sake of completeness. The physical theory of magnetic reconnection is developed in detail, for instance, in Magnetic Reconnection: MHD Theory and Applications, by Priest & Forbes, Cambridge University Press, 2000; Nonlinear Magnetohydrodynamics, by Dieter Biskamp, Cambridge University Press, 1993 & 1997, and Plasma Astrophysics, by Tajima & Shibata, Westview Press, 1997 & 2002. Furthermore, I have studied the material and do not see a problem with it. I have even had some experience of my own doing research in space plasma physics, if one is allowed to "blow his own horn" (Correlation studies between solar wind parameters and the decimetric radio emission from Jupiter, S.J. Bolton, et al., Journal of Geophysical Research - Space Physics 94(A1): 121-128, January 1, 1989).

If your assertion is correct, that magnetic reconnection theory is wrong, then can you explain why the theories developed in these, or similar sources, are wrong? Can you point to specific arguments where the theory of magentic reconnection is not self consistent, or perhaps is inconsistent with some other aspect of the physics of electromagnetism?

I assert that the theory of "frozen flux" is also valid. As a justification for that assertion, I point to the same sources for the same basic physics, but will add something that might be of interest. The assertion that flux can be frozen into a plasma originated with Hannes Alfven in 1943 (On Sunspots and the Solar Cycle, Arkiv f. Mat., Astron. o. Fys., Volume 29A (12), p. 1-17) and is further developed by him in his later textbook Cosmical Electrodynamics, by Alfven & Falthammer, Oxford University Press, 1963 (2nd ed). It is the authors' opinion in that book, that the frozen flux theorem is dubious for low density plasmas, but valid for higher density plasmas (i.e., p. 191). For the most part, the current theory of frozen flux agrees with that conclusion, but it is currently thought that the frozen flux theorem will work for a low density plasma, if the kinetic cenergy density of the plasma is significantly greater than the energy density of the magnetic field, which appears to me to satisfy the criteria set down by Alfven & Falthammer, who assert that if the magnetic field is weak, the fluid will behave according to the normal physics of fluids.

if your assertion is correct, then the frozen flux theorem originated by Alfven is wrong, or the current theory is wrong, Can you explain where the theory of the frozen flux approximation, as developed in these or similar sources, is wrong? Can you be specific about the physical and/or mathematical inconsistencies?

If your own assertions are incorrect, or unsupportable, then the rest of the argument is rendered moot, since it would then be established that the current theory of plasma physics is apparently valid. So I will wait and see how you justify these assertions before continuing.

__________________
The point of philosophy is to start with something so simple as not to seem worth stating, and to end with something so paradoxical that no one will believe it. -- Bertrand Russell

Hi Tim,

Before we proceed in a more organized fashion, I'd like to hear your view on this story, if I'm correct your one of the scientists that worked on Jupiter's magnetic field and the Jupiter/Io connection.
There are some new insights here, especially the last paragraph, where the dust "jets" were found in unexpected places.
I promise to return to the previous post,

Cheers.

Well, it's a news article, so it works hard to sell the mystery, without bothering to mention that much of the mystery was solved some time ago.

Note that the last sentence begins with "This result is consistent with theoretical expectations ...", an interesting conclusion from someone who is supposed to be "baffled", as the news article likes to say. This is just one of a series of papers on this specific issue, as well as the more general issue of dust in the Jovian system. The mechanism whereby the dust is accelerated may not be known in every detail (what ever is?), but the dust can hardly be uncharged in that environment, and will be accelerated by the electric fields induced by the rotational motion of the magnetic field. It's not all that wierd, once you actually sit down & do the work.

I don't think there's any new insight here at all. There are two ways for something to be "surprising", or "unexpected". One way is that you think a lot about what you expect to see, and then get surprised by something. The other way is to not think much about what you expect, and get surprised by something. So, the question arises, why would anyone think about Io as a source of dust? In hindsight, they should have, but in fact they didn't, even though Io was already known as a source of ionized gas. So everyone was originally 'surprised", not because they really expected something else for a good reason, but because they had naively expected something else, without having given the matter much thought before. We can't think of and anticipate everything.

So now the dust comes from an unexpected direction. It's a problem, and like all other problems, it will be solved. But it certainly does not look like a big deal to me.

Hi Tim, thanks for the link to the article pdf, it's "easier" when the article is written by scientists instaed of science journalists. Just a quick response.

I don't know why in hindsight one would expect dust to be accelerated by the plasma torus, shouldn't the particles remain in Io's atmosphere like particles do here on Earth? Or is this effect also present here on Earth? Maybe the particles are already charged before entering Io's plasma torus, or show acceleration as in (dare I mention) discharging double layers?

I'm wondering which model the data discussed in the article is confirming. The way I read it, the model starts with a local time dependence that is shown in the dust flux, whatever is the cause of the time-depedence in Jupiter's magnetic field?

Cheers.

One should have expected it because the surface gravity of Io (GM/r^2) is only about 0.18 of the surface gravity for Earth, and the escape velocity (sqrt[2GM/r]) is only about 0.23 of the escape velocity for Earth. So one should at least consider that the Io volcanoes could accelerate dust beyond escape velocity. Once you actually think about it, it seems obvious, but it might not otherwise (Physical Parameters of the natural satellites, from the JPL Solar System Dynamics Group). it doesn't happen on Earth (for dust) because there is too much gravity, but Earth does lose gas out the top of the atmosphere, both due to thermal escape, and non-thermal escape of ions along the magnetic field.

There are certainly ionization processes involved in volcanic eruptions, so the dust could be "pre charged". But even if not, it's hard to avoid picking up charge in the exciting environment around Jupiter. And as for being accelerated by plasma double layers, it's not likely. Aside from the fact that it would be nigh onto impossible to create a stable double layer in such a turbulent environment, it would also have to be spatially humongous. What would create such a double layer? How could it escape being observed? And why should anyone worry over such unlikely causes, when perfectly ordinary causes are evident?

All planetary magnetic fields are intrisically time dependent because the dynamos that generate them are time dependent, because nothing ever happens in nature with rigorous constancy, except of course the constants themselves (Earth's Inconstant Magnetic Field, and Planetary Magnetism from The Great Magnet, the Earth).

But leave us also to remember not to deflect the topic away from the more important fundamentals. Physics says that magnetic field lines cross & reconnect, while VanderL says otherwise. It would be nice to know what you know that the rest of the world seems mostly to have missed.

I also note that this thread has received 123 "hits" since Monday evening (Pacific time), even though it's "just we two". Somebody must be interested.

Now that's interesting, 123 is that a lot? Maybe 5 from myself, a few from you, I'd like to know what others think when they read this thread (or then again, maybe I don't).

Gotta run, catch you later, I'll not forget the real issue.

Cheers.

I'm following along, just feel no need to comment on anything. One comment though, while I'm at it--it's been known for a while that the volcanoes on Io can accelerate material to escape velocity while they are erupting. The "surprise" really shouldn't have been a surprise but, as Tim says, sometimes the obvious gets overlooked.

__________________
All civilizations become either spacefaring or extinct.~ Carl Sagan ~

Humanity must rise above the Earth, to the top of the atmosphere and beyond, for only then will we fully understand the world in which we live.~Socrates, 500 B.C. ~

Let every man judge according to his own standards, by what he has himself read, not by what others tell him. ~Albert Einstein~