Electric universe theories here.

[sol invictus]

Apparently so, and apparently it explains that individual charged particles follow predictable and mathematically quantifiable paths when exposed to EM fields. They individually and collectively share that trait.

That's true - but it's not useful when applied to 10^23 particles, because it's completely impossible to keep track of them all.

Yes one does have to learn to walk (with a single particle) before one can learn to run (with a bunch of them). It doesn't now however change the fact that these formulas relate to *PHYSICAL* things called "electrons", "ions" and "photons".

You still don't get it. Sure, the formulas of MHD "relate" to electrons, ions etc., because MHD is often used as an approximate description of fluids containing them. But it does not describe the particles or molecules the fluid is composed of in any way, shape, or form other than in huge quantities and under certain conditions. From the MHD description, you couldn't determine what the particles are.

Look - MHD can be used to describe an extremely hot plasma. It can also be used to describe salty water at room temperature. Precisely the same theory, the same equations with a few parameters different - and yet the particles involved are totally different. Why does it work? Because the collective behavior in both cases is governed by the fact that both are fluids and both are electrically conductive. It makes almost no difference what the particles are, and the MHD approximation doesn't describe those differences.

Yes I would, and of course the "properties" (like the freezing point) of water are of interest. For instance, water does not behave in space at all the way "Newtons theories" might expect.

Freezing point is a good example, actually. When water freezes, the hydrodynamic description totally breaks down. So that's one parameter you need if you want to know when hydrodynamics is valid (although of course knowing that still doesn't mean you know what the molecular constituents are). Similar things go for MHD - it will break down in various regimes (tus can tell you more about that than I can), and it's clearly desirable to know where. But MHD itself doesn't contain much information about where it will break down, any more than the Navier-Stokes equations for water tell you about the water-ice phase transition - that's something external you have to know about.

Don't you mean dihydrogen monoxide?

Oops - thanks.

 

[DeiRenDopa]

That's just flat-out false. There's no equivocation, no way around it - it's just not true. Here's an explicit counterexample:

[latex]$\vec B(x,y, t) = a(t) y \hat x + b(t) x \hat y$[/latex].

If a and b are constants, nothing changes. But give them any time dependence at all (except a/b is constant) and the field lines reconnect at x=y=0. Draw a picture if you're not capable of doing the math (yes, MM, that means you).

Before we can talk about what "connects" and "reconnects" at various locations, I need to ask you two basic "physics" questions, starting with the same question I put to tusenfem.

In terms of actual "physics" and physical things, what exactly *DO* you think these formulas relate to *if* not the charged particles of the plasma and not the photons of the EM field? Inquiring minds really want to know.

In terms of what "physically reconnects", what *physical things(s)* are you claiming is 'reconnecting' at *ANY* location in plasma?

I expect you to answer these two question too DRD.

(bold added to last sentence)

I feel somewhat honoured, to be considered as belonging to an exclusive club of two members, with si the other one!

But as CMO (Chief Membership Officer) of this exclusive club, I have decided to invite several others to join: Ziggurat, tusenfem, Tubbythin, Reality Check, GeeMack, ..... and Zeuzzz.

However, while there are still only two members, allow me to quote from the collective works of these two:

"Known forces of nature"

Here's an idea, wrt MM's "known forces of nature".

Start with gravity, which is, per his own statements, one such.

IIRC, MM proposed a very simple test which demonstrates that gravity, as a force of nature, exists*; something like this: hold your Tesco plasma ball in one hand, hand facing down; with your other hand underneath it, palm up, let go of the ball ... the ball will drop into your (lower) hand; ergo, gravity exists.

As was pointed out, and as is clear anyway, all this test shows is that the plasma ball falls when released from one's hand; to call that 'gravity' is rather underwhelming.

However, we can proceed empirically - being very careful to define just what we mean by this word - and do lots of tests with lots of different objects, in lots of different places, at lots of different times.

We will find - empirically - that there are plenty of cases where objects do not drop, or fall, when released; for example, a leaf on a windy day, a piece of wood released under water. And we need to confront the problem of induction too.

By being careful, and using induction, we can gradually build more and more powerful summaries of the results of hundreds, thousands, millions, ... of tests, and in the best of these summaries the word 'gravity' will be used, as will the word 'nature'.

In that sense the word 'gravity' may be said to have great explanatory (and predictive) power.

In parallel, and to some extent overlapping, we may develop other summaries of empirical tests (of 'nature') which include another word with great explanatory (and predictive) power, 'force'.

Historically, with some anachronisms and a bit of revisionism, this gets us up to somewhere in the 1500s, maybe a bit earlier, maybe a bit later.

Now we add a true revolution, which I shall term the quantitative revolution ... we can move on from nice word summaries to adding first numbers and then equations, and 'gravity as a force of nature' becomes something whose explanatory and predictive powers expand enormously ... but only if the equations and numbers are understood! We are now in the time of Galileo (more or less).

At that time the heavens and Earth were separate - nature consisted of two almost totally independent parts, each with its own 'forces'; how the planets moved across the sky, for example, had nothing to do with how cannon balls (and feathers) fell when let go.

Then, in the myth, an apple fell on Newton's head while he was gazing at the Moon (it was daytime) ... and nature became unified, and the universal law of gravitation was published.

It was quickly tested, by 'curve fitting' - applying math to points in the sky** - and found to work.

And a century or so later - well after Newton had died - a key part of Newton's law was tested in the lab.

So what does all this have to do with MM's ideas? A great deal actually.

First, 'known forces of nature' are so known via equations and numbers only; if you work at the 'qualitative' level, you cannot have 'known forces of nature'.

Second, a century (or more) may well pass between the first publication of the equations and numbers describing a 'known force of nature' and its testing in the lab.

Third, the application of math to points on the sky can lead to acceptance of a new 'force of nature'.

And so on.

Now we know, from a great many of MM's posts, that he rejects all three of the above points, especially the third one. This alone makes his approach to science very different than that of scientists - or at least physicists - over the past four+ centuries ... and it means that the discussion we should be having is not about Birkeland, the solar wind, inflation, Einstein's EFE, negative pressure, etc; rather it should be about what constitutes science (or at least physics).

If we were to have such a discussion, I think we'd find that a key aspect of MM's approach is an unstated, and possibly unrecognised, misunderstanding of equations and numbers; in short, a world where the quantitative revolution didn't happen.

* I think I've got it right; if not, would someone please point me to his post(s) which say otherwise?
** That's not exactly what MM said, in another context, but it's close, I think.

(source)

Now we know, from a great many of MM's posts, that he rejects all three of the above points, especially the third one. This alone makes his approach to science very different than that of scientists - or at least physicists - over the past four+ centuries ... and it means that the discussion we should be having is not about Birkeland, the solar wind, inflation, Einstein's EFE, negative pressure, etc; rather it should be about what constitutes science (or at least physics).

Indeed. But such a discussion wouldn't be necessary with anyone other than MM, and with him it would be excruciatingly tedious.

If we were to have such a discussion, I think we'd find that a key aspect of MM's approach is an unstated, and possibly unrecognised, misunderstanding of equations and numbers; in short, a world where the quantitative revolution didn't happen.

One relatively interesting question related to that is why math works so well (whether being long since settled in everyone's mind but MM's). I think the answer is that math is science in the sense that it is discovered rather than invented. That is, it might appear that we invented math - we made up some arbitrary rules and played with them. But if that were the case one wouldn't expect it to work as a description of physics any better than English words do. Instead, we are capable of making incredibly precise predictions and checking them.

How can that be? Only if math is simply a symbolic expression of a deep set of truth about the world - that it operates according to the rules of logic.

(source)

So, the simplest answer to your first question ("In terms of actual "physics" and physical things, what exactly *DO* you think these formulas relate to *if* not the charged particles of the plasma and not the photons of the EM field?") is something like "magnetic fields described in a quantitative form that is logically and mathematically consistent with Maxwell's equations (and, in case you have forgotten, these equations are consistent with the totality of experimental and observational results of the late 19th century)." Going a little further, if you wish to relate the equation(s) to charged particles in a plasma and photons, then you need to switch to QED, and recognise that Maxwell's equations are only an approximation.

I'm sorry to say that your second question ("In terms of what "physically reconnects", what *physical things(s)* are you claiming is 'reconnecting' at *ANY* location in plasma?") is not meaningful to me ... would you mind clarifying please?

The bottom line here MM is this: as with "known forces of nature", the "*physical things*" at the heart of this sub-thread on plasmas, magnetic reconnection, etc can be understood only in terms of the ~half millennium old quantitative revolution in physics. Sadly, there is an abundance of evidence - objective, incontrovertible, independently verifiable evidence - that you, MM, live in a world where this revolution has yet to happen ... and it follows that you will not, nay cannot, understand the answers I have given^.

^ ditto those, future, ones by si, and any other members of the (newly expanded) club ...

 

[DeiRenDopa]

I want to hear Sol and DRD respond to this question as well. I want to see if they are as clueless as you are.

Wow! Nominated twice now to be in an exclusive club!!

Here's tusenfem's earlier post, that lead to MM's (quoted):

The movement of charged particles creates "magnetic fields', but that EM field is carried by photons. The only "things" that MHD theory describe or can describe are the particles of plasma (the electrons/protons/ect) and the photons that make up the EM field. You don't even seem to understand *WHAT* these formulas relate to in terms of actual physical things like photons and the actual particles of plasma. In terms of actual "physics" and physical things, what exactly *DO* you think these formulas relate to if not the charged particles of the plasma and not the photons of the EM field? Inquiring minds really want to know.

(my bold)
WRONG!!!!!!!!!!! MHD has an H which stands for hydro, this theory describes the plasma as a fluid NOT as particles.

MM, I'm sure you were already pretty certain of the answer before either si or DRD replied (ditto Tim Thompson, maybe in the future), and since your post (that I am quoting), si has joined tusenfem in clueless-land (as have several others).

Well, I am honoured to say that I am, in this particular case, as clueless as tusenfem ... MHD treats plasmas as fluids, as is obvious from even a cursory read of any standard textbook ...

 

[Michael Mozina]

That's true - but it's not useful when applied to 10^23 particles, because it's completely impossible to keep track of them all.

Alfven's "method" of describing MHD theory begins with the discussion of the flow of a single charged particle. Only by understanding the effect of the EM field on a single charged particle, can you begin to appreciate the effect of MANY such particles and a "flow" of such particles. He certainly "kept track" of single charged particles. Their is a "fluid-like" component to plasma, but the magneto side of MHD theory is all about understanding the effect of the EM field on individual and collective charged particles. Even the charge of the particle has a very significant outcome on it's movement patterns in the EM field. We don't need to "keep track of them all" once we figure out what happens to a few test particles, but it is often handy (and Alfven's personal teaching technique) to simply look at the flow of a single charged particle to understand the "flow patterns" that occur when we put many of them into the 'circuit'. Alfven continually refers to these current flows in terms of circuits and "particles". You can't ignore influence of the EM field any particles.

You still don't get it. Sure, the formulas of MHD "relate" to electrons, ions etc., because MHD is often used as an approximate description of fluids containing them.

Well, ultimately the math is designed to "approximate the physical processes that occur inside the plasma."

But it does not describe the particles or molecules the fluid is composed of in any way,

Sure it does. Even the charge of the particle matters.

From the MHD description, you couldn't determine what the particles are.

From the MHD description we realize that individual particles act "collectively" and form "organized structures" like those Birkeland currents and plasma filaments in an ordinary plasma ball. It's advantageous now in MHD theory to treat them as "circuits" rather than individual charged particles.

Look - MHD can be used to describe an extremely hot plasma.

The only way we're going to generate that much "heat" in a light plasma is to add "circuit energy" to the system. While plasma is an "excellent' conductor, it is not a 'perfect' conductor, and heating occurs as a result of the current flow in and through the plasma and the collisions that occur inside the z-pinch. We observe this heating process in nature in every discharge here on Earth.

It can also be used to describe salty water at room temperature. Precisely the same theory, the same equations with a few parameters different - and yet the particles involved are totally different. Why does it work? Because the collective behavior in both cases is governed by the fact that both are fluids and both are electrically conductive. It makes almost no difference what the particles are, and the MHD approximation doesn't describe those differences.

But your "salty water" has "properties" that mimic plasma. The "properties" of the "particles" that make up the medium matters a great deal. It's only because the salt water molecules conduct electrical energy and have a north and south pole these formulas work in a similar way. The properties of the particle matter.

Oops - thanks.

Oh well, I missed it too darn it.

 

[sol invictus]

Their is a "fluid-like" component to plasma, but the magneto side of MHD theory is all about understanding the effect of the EM field on individual and collective charged particles.

Michael, this is very simple. The "H" in MHD stands for "hydro". That means the plasma (or salty water, or whatever) is treated mathematically as though it was a completely continuous substance, with no molecular substructure.

Don't believe me? Go look at the equations. Notice how everything involved is a field, a density, a viscosity, etc.? Notice how there are no indices keeping track of individual particles?

Sure it does. Even the charge of the particle matters.

Of course the properties of the particles matter - for example if there were no charged particles at all in the fluid in question, you could forget about the "M" in MHD. No one ever said otherwise. But they only matter in so far as they determine the bulk properties of the fluid - its conductivity, viscosity, etc. Given just those parameters, you have all you need to do MHD. And the map only goes one way: you cannot reconstruct the properties of the constituent particles given the MHD description, and you certainly cannot keep track of the motions of individual particles.

If you take a poll of 1,000 random people, you can extrapolate that it to a much larger group - say an entire country. Now, would you regard that extrapolation as a description of all the individuals in that entire country? Of course not, since the poll only sampled a tiny fraction of all those people, and only asked them a few questions. And yet, the poll (if it was done well) is useful for predicting some aspects of the mass behavior of all the people in the country under some circumstances, like who they're going to elect next week.

Obviously the beliefs of those people matter for the results of the poll, as does knowing something about how individuals behave (for example, that they rarely switch from extreme left to extreme right in one week) - but the poll results don't tell you anything about how any particular individual will vote, because they don't keep track of that.

I don't know how I can make this any more clear...

 

[Michael Mozina]

Wow! Nominated twice now to be in an exclusive club!!

If by "exclusive club", you mean people that have no clue about the actual physics going on inside the plasma, wow, what an honor.

Well, I am honoured to say that I am, in this particular case, as clueless as tusenfem ... MHD treats plasmas as fluids, as is obvious from even a cursory read of any standard textbook ...

Tusenfem also promotes something that Alfven himself called "pseudoscience" and tusenfem has no idea of what is physically occurring inside the plasma at the point of "reconnection".

MHD also treats plasmas as particles and circuits as any of Alfven's later writings will attest. At the level of physics, there is a kinetic energy transfer process going on between plasma particles and the EM field carrier particles inside plasma. It's not a 'magnetic" process, it's an *ELECTROmagnetic* process that has a *PHYSICAL* component to it. As long as you ignore the physics, it may be possible to believe that "magnetic lines" (which lack physical substance) can "reconnect". Particles and circuits reconnect. When photons of a changing EM field influence the movement of charged particles that is called "induction". It has a proper name already.

There are only two possible sources of the kinetic energy at the point of reconnection, plasma particles and carrier particles of the EM field, AKA photons. Induction has a proper name, so any movement of the particles as a result of changes to the EM field are not a form of "magnetic reconnection", they are a form of induction. There is no physics to support your belief in "magnetic reconnection". The only two sources of kinetic energy are "particle kinetic energy" and the EM carrier particles that go along for the ride.

A "reconnection" inside a current sheet is nothing more than a "short circuit" between two ordinary filaments, the same kind of pinched filaments inside a plasma ball. While the "circuits' may reconnect, and induction may occur as a result of changes in the magnetic field during the transition period, but the total circuit energy determines what happens at the point of 'reconnection'.

At the level of physics, there are only plasma particles and carrier particles of the EM field to transfer energy at the point of 'reconnection'. What else exists *physically* that can "reconnect"? Induction is not "magnetic reconnection". Circuit reconnection is not "magnetic reconnection'. A short circuit between two z-pinched filaments is not a form of "magnetic reconnection', it is a form of "circuit reconnection".

 

[Ziggurat]

At the level of physics, there is a kinetic energy transfer process going on between plasma particles and the EM field carrier particles inside plasma.

Back to this old misconception, I see. Michael, this has been explained to you before, in great detail: the potential energy stored in electromagnetic fields is not kinetic energy.

When photons of a changing EM field influence the movement of charged particles that is called "induction". It has a proper name already.

You will find that photons appear nowhere within the MHD equations. Or even Maxwell's equations.

 

[Michael Mozina]

Michael, this is very simple. The "H" in MHD stands for "hydro".

Nobody doubts this sol. The M in there stands for magneto, and even the charge of the particles influence the movement of the fluid-like plasma. You can't ignore plasma properties like charge. They matter too.

Sooner or later you're going to recognize that there there is a physical process occurring in the plasma between electrons, ions and carrier particles of the EM field which all these mathematical equations attempt to "describe". The particles do the "reconnecting", not the 'magnetic lines'. The circuit energy determines the "reconnection rate" at the point of 'reconnection'. It is all about "circuits' and "particles" at the point of kinetic reconnection. The magnetic line is nothing but a "carrier particle". It is therefore "particle reconnection". It is also logical and rational to call it "circuit reconnection". It is irrational to call it "magnetic reconnection' because magnetic lines are nothing more than carrier particles in motion and the transfer of energy between photons and charged particle is kinetic in nature, and it has a proper name in "circuits", called "induction".

 

[Ziggurat]

Nobody doubts this sol. The M in there stands for magneto, and even the charge of the particles influence the movement of the fluid-like plasma. You can't ignore plasma properties like charge. They matter too.

What, you think charge can't be treated as a continuum property? Of course it can be. And it usually is.

But perhaps you just don't understand what everyone means by "continuum" here. Is that your difficulty?

 

[Michael Mozina]

You will find that photons appear nowhere within the MHD equations. Or even Maxwell's equations.

What are the carrier particles of the EM field, and how do they make make charged particles move?

 

[sol invictus]

Nobody doubts this sol. The M in there stands for magneto, and even the charge of the particles influence the movement of the fluid-like plasma. You can't ignore plasma properties like charge. They matter too.

I like how you completely ignored the rest of my post: like where I said

Of course the properties of the particles matter

and explained precisely how. That kind of stupidly transparent trick doesn't buy you anything, Michael.

Anyway, this little sub-conversation is over. You were dead wrong, as usual - MHD does not describe particles; it's a continuum fluid approximation - and we've beaten it into the ground to the point even you must know it.

 

[Ziggurat]

What are the carrier particles of the EM field

There are no carrier particles in classical electrodynamics. There aren't carrier particles in any classical field theory. Photons are the carrier particles in quantum electrodynamics, but MHD doesn't use quantum electrodynamics, it uses classical electrodynamics. Don't you know this?

 

[Michael Mozina]

There are no carrier particles in classical electrodynamics. There aren't carrier particles in any classical field theory.

So by "classical", I'm supposed to now limit my understanding of the EM field to what we knew in the 19th century?

 

[Tubbythin]

So by "classical", I'm supposed to now limit my understanding of the EM field to what we knew in the 19th century?

Nope. But if we start talking quantum we're no longer discussing MHD.

 

[Michael Mozina]

MHD does not describe particles;

MHD theory does describe the collective moment of charged particles in terms of "circuits" and "particle flow". As long as you refuse to acknowledge the electro half of "electromagnetism", you'll continue to be mystified by things Birkeland understood and "predicted" over 100 years ago. These high temp plasmas have *NOTHING* to do with "magnetic reconnection" and everything to do with "current flow" inside of plasma. Even single coronal loops reach millions of degrees, not just the ones that "reconnect" with other loops. MHD theory certainly does describe these particle/circuit behaviors in plasma and it has a "particle" (E) orientation as well as a field (B) orientation. Alfven switched between them interchangeably but he understood *WHICH* methods worked best in specific conditions. Your industry only understands the B field orientation of MHD theory and you utterly ignore the particle orientation which Alfven applied to all activities in space.

 

[Ziggurat]

So by "classical", I'm supposed to now limit my understanding of the EM field to what we knew in the 19th century?

I don't care what you do with your "understanding", such as it is. But MHD uses classical electrodynamics, not quantum electrodynamics. And there are no photons in classical electrodynamics.

 

[Michael Mozina]

Nope. But if we start talking quantum we're no longer discussing MHD.

Sure we are. We are simply improving our understanding of the entire physical process by recognizing that there is a carrier particle of the EM field.

 

[Michael Mozina]

I don't care what you do with your "understanding", such as it is. But MHD uses classical electrodynamics, not quantum electrodynamics. And there are no photons in classical electrodynamics.

I don't care if there are photons in classical electrodynamics. There are photons in nature and they are the recognized carrier particle of the EM field.

 

[DeiRenDopa]

[...]

MHD also treats plasmas as particles and circuits as any of Alfven's later writings will attest.

(bold added)

OK, that should be easy enough to demonstrate ...

... please provide BOTH an MHD equation from one of Alfvén's "later writings" AND its derivation (together with a sufficiently unambiguous reference), and explain how plasmas (or a plasma) are (is) treated as particles.

For avoidance of doubt, my question is about an equation and its derivation.

At the level of physics, there is a kinetic energy transfer process going on between plasma particles and the EM field carrier particles inside plasma. It's not a 'magnetic" process, it's an *ELECTROmagnetic* process that has a *PHYSICAL* component to it. As long as you ignore the physics, it may be possible to believe that "magnetic lines" (which lack physical substance) can "reconnect". Particles and circuits reconnect. When photons of a changing EM field influence the movement of charged particles that is called "induction". It has a proper name already.

[...]

OMG, you really don't have a clue, do you?

Déjà vu all over again, with the Casimir effect and pressure on the side ...

 

[Ziggurat]

I don't care if there are photons in classical electrodynamics. There are photons in nature and they are the recognized carrier particle of the EM field.

Nobody denied that. But photons can frequently be ignored because the classical description is sufficient. Likewise individual particles of a fluid can frequently be ignored and only the continuum properties (density, viscosity, etc) considered, as in the Navier-Stokes equation. And in MHD? The individual particles (including photons) are also ignored. It is a classical continuum theory. Nobody denies that the particles exist, but there's simply no need to treat them individually. So we don't. Yes, yes, Alfven mentions individual particles when describing electrodynamics in his intro. Ever heard of the concept of a "test charge"? That's what he's talking about. The actual equations, the actual math that Alfven does with MHD, is all continuum.

But you wouldn't know that, because you've never actually done a calculation in your life.

And once again, even in quantum electrodynamics, the energy stored in electric and magnetic fields is not kinetic energy.