Problems With Magnetic Reconnection

[Reality Check]

The experiments clearly demonstrate that the plasma flow is NOT neutral, it's driven by CHARGE SEPARATION, CATHODES and ANODES.

That is idoitic: Plasma flow cannot be charged (it is a flow!).
Your ignorance of a little thing called physics has erupted again.
A plasma is made of negative and positive particles. When it flows both charges are flowing. That is the movement of an overall neutral material. There is no current by definition.

Ya, like a lightning bolt is "neutral overall"!

More idoicy: lightning is not a plasma. It produces plasma.

Dude,....

Dude, you are still obssessed by the word cathode and displaying your total inability to understand the experiment's abstract.

 

[GeeMack]

http://adsabs.harvard.edu/abs/2008AGUFMSM31A1706L

Any chance you're going to read it and deal with it?

I agree with Tim, Reality Check, and pretty much every actual physicist who has reviewed and understands the experiment.

One cathode is used to create the plasma.
Other cathodes are used to create current channels through the plasma. These current channels interact (they do not reconnect if only for the simple reason that they were never connected !).

I disagree with the unqualified, unsupported assertions, apparently the result of misunderstanding or focusing on a few dishonestly cherry picked terms while ignoring the actual description of the experiment, assertions that simply claim without evidence, support, or explanation, that it is about "circuit reconnection" rather than magnetic reconnection.

 

[Perpetual Student]

Wow!!! I'm amazed. Mozina (still on ignore) is capable of thought independent of his EU cult. Congratulations to all involved in attaining this unexpected happening. I guess this beast of a thread can now be put to rest.

 

[Tim Thompson]

What Electric Fields?

The actual experiments begin and end with cathodes, anodes and ELECTRIC fields that 'reconnect' via the redirection of current.

What electric fields?
What is the difference between 'reconnect' (in quotation marks) and reconnect (without quotation marks)?
What force do you think is redirecting the currents?
Do you agree that there are magnetic fields present in the plasma?
If you do, where are the magnetic fields and what are they doing?

 

[Michael Mozina]

What electric fields?

Come on Tim:

"The behavior and interaction of magnetic flux ropes have long been a topic of interest to solar and space plasma physicists, but few laboratory experiments have been performed as it is necessary to have a relatively collisionless plasma and currents with significant self-generated fields. Movable lanthanum hexaboride (LaB6) cathodes have been developed to study the 3D dynamics of flux ropes in the Large Plasma Device (LaPD). Each ~2.5 cm LaB6 cathode can produce current densities of 5-20 A/cm2 and ΔB/B ~ 10%. The background plasma (n ~ 2 × 1012 cm-3, d ~ 60 cm, L ~ 18 m, and τrep= 1 s) is produced with a DC discharge using a pulsed barium oxide-coated cathode. The two current channels are created by biasing the LaB6 cathodes with respect to a grid anode at the opposite end of the chamber. They are emitted parallel to each other and the background B field. J × B forces cause the currents to move across the field and interact. Reconnection has been observed at multiple locations between the two currents. The role of reconnection in these interactions will be investigated through detailed volume measurments of the magnetic field and current density (65000 time steps at 20000 spatial points). Data from Langmuir probes and microwave horn antennas will also be presented."

I highlighted the electric field components for you. The cathode on the left is originally connected to the anode on the right. During "reconnection", some of the current is diverted from the cathode on the left, to the anode on the left, or from the cathode on the right to the anode on the right. All that's happening is two ELECTRIC fields are "reconnecting" via the redirection of current between the two cathodes and two anodes.

What is the difference between 'reconnect' (in quotation marks) and reconnect (without quotation marks)?

Nothing. It's a personal idiosyncratic quirk, just my way of trying to emphasize words like I might try to do in a verbal conversation. Get over over it.

What force do you think is redirecting the currents?

I bolded the forces in the abstract. It is J X B.

Do you agree that there are magnetic fields present in the plasma?

Sure. Anytime there is a flow of current through the plasma there are necessarily magnetic fields present.

If you do, where are the magnetic fields and what are they doing?

As far as I can tell they simply divert the current from one electric field to another. The anodes and cathodes are ultimately 'reconnecting' via the redirection of current.

 

[Michael Mozina]

That is idoitic: Plasma flow cannot be charged (it is a flow!).

This is completely false and it can be easily demonstrated to be false with an ordinary plasma ball RC. When we turn on the plasma ball, a 'circuit' is completed through the plasma. Those filaments that light up carry current from the glass cathode to the central anode.

You're essentially trying to ignore the fact that you're ultimately "reconnecting" a couple of cathodes and anodes via the redirection of current.

 

[GeeMack]

Come on Tim:


I highlighted the electric field components for you. The cathode on the left is originally connected to the anode on the right. During "reconnection", some of the current is diverted from the cathode on the left, to the anode on the left, or from the cathode on the right to the anode on the right. All that's happening is two ELECTRIC fields are "reconnecting" via the redirection of current between the two cathodes and two anodes.


Nothing. It's a personal idiosyncratic quirk, just my way of trying to emphasize words like I might try to do in a verbal conversation. Get over over it.


I bolded the forces in the abstract. It is J X B.


Sure. Anytime there is a flow of current through the plasma there are necessarily magnetic fields present.


As far as I can tell they simply divert the current from one electric field to another. The anodes and cathodes are ultimately 'reconnecting' via the redirection of current.

The extreme misunderstanding of the reference material demonstrated in the quoted post does not constitute a valid criticism of magnetic reconnection. I'm sure pretty much every professional plasma physicist on Earth agrees. So even if the ridiculous interpretation described in the quote were true, no argument has ever been assembled that is objective, scientific, rational, or cogent to suggest it might be. Argument failed.

 

[GeeMack]

This is completely false and it can be easily demonstrated to be false with an ordinary plasma ball RC. When we turn on the plasma ball, a 'circuit' is completed through the plasma. Those filaments that light up carry current from the glass cathode to the central anode.

You're essentially trying to ignore the fact that you're ultimately "reconnecting" a couple of cathodes and anodes via the redirection of current.

The workings of a plasma ball have been described numerous times in this and other threads. The physics involved are entirely different from plasma physics as it relates to magnetic reconnection. The argument making a comparison is so ludicrously wrong it barely merits a response other than ridicule. Argument failed.

 

[Michael Mozina]

The extreme misunderstanding of the reference material demonstrated in the quoted post does not constitute a valid criticism of magnetic reconnection.

Your personal extreme denial of the cathodes, anodes and current that "reconnect" won't fool anyone GM. You're just making yourself look like a fool (again).

I'm sure pretty much every professional plasma physicist on Earth agrees.

I have no idea where you get off trying to speak for every plasma physicist on Earth. I'm sure they don't much care for you putting words in their mouth, particularly the two authors we are discussing. You personally are clueless and everyone knows that. If you don't have anything useful to add to this conversation from the standpoint of *SCIENCE*, just go away.

Argument failed.

The only reason that the argument failed is because you refuse to get off of the denial-go-round about the fact that the cathodes and anodes generate the current and the fact the the CURRENT reconnects two ELECTRIC fields. The authors of that paper were not in denial of these facts, in fact they clearly explained that the currents do the interacting. You personally have no right to speak for anyone except yourself, and that ain't saying much IMO.

 

[Michael Mozina]

Ah, did GM "mislead" you again? Have you heard that quote: "Fool me once, shame on you, fool me twice, shame on me"?

 

[Zeuzzz]

This threads made me realize that different people have different opinions on different things. Weird.

 

[Reality Check]

Plasma balls do not contain plasma. They contain plasma filaments

When we turn on the plasma ball, a 'circuit' is completed through the plasma.

More ignorance: plasma balls

Most commonly, plasma globes are available in spheres or cylinders. Although many variations exist, a plasma lamp is usually a clear glass orb filled with a mixture of various gases (most commonly helium and neon, sometimes with other noble gases such as xenon and krypton) at low pressure (below 0.01 atmosphere)[3] and driven by high-frequency alternating current at approximately 35 kHz, 2–5 kV, generated by a high-voltage transformer. A much smaller orb in its center serves as an electrode. Plasma filaments extend from the inner electrode to the outer glass insulator, giving the appearance of multiple constant beams of colored light (see corona discharge and electric glow discharge). The beams initially follow the electric field lines of the dipole but move upwards due to convection.[citation needed]
Placing a hand near the glass alters the high-frequency electric field, causing a single beam to migrate from the inner ball to the point of contact.[1] An electric current is produced within any conductive object near the orb, as the glass does not block the electromagnetic field created by the electric current flowing through the plasma (though the insulator does block the current itself).[citation needed] The glass acts as a dielectric in a capacitor formed between the ionized gas and the hand.

• They contain gas. The discharges through that gas create plasma filaments which emit visible light.
• There is no separate cathode and anode.
  There is a central electrode and an outer insulator. The high frequency alternating current means it is both an anode and a cathode.

Basically what happens is that the alternating current at the electrode generates plasma at the electrode.
This plasma then forms the filaments (according to the article by flowing along the electric field and through convection).

 

[Reality Check]

A flow of plasma is not an electric current

This is completely false and it can be easily demonstrated to be false with an ordinary plasma ball RC.

As noted before the plasma ball thing is a result of your ignorance of how a plasma ball works.

The physical fact is that a flow of plasma is not an electric current.

Electric current is a flow of electric charge through a medium.

When a plasma flows it carries equal numbers of electrons and ions, i.e. there is no net flow of electric charge. That is why scientists use the word flow instead of current.
There are current sheets in plasma. Scientists use the term current sheets to distinguish the current in these sheets from a flow.

Thus a flow of plasma is like a flow of water. That is why magnetohydrodynamics has the 'hydro' bit in it. That is why the flow is caused by pressure
Magnetic reconnection

The resistivity of the current layer allows magnetic flux from either side to diffuse through the current layer, cancelling out flux from the other side of the boundary. When this happens, the plasma is pulled out by magnetic tension along the direction of the magnetic field lines. The resulting drop in pressure pulls more plasma and magnetic flux into the central region, yielding a self-sustaining process.

Or if you want to look at it another way: The magnetic tension force creates a pressure that acts on the plasma. The plasma then flows.

 

[Tim Thompson]

Electric currents and magnetic reconnection III

The actual experiments begin and end with cathodes, anodes and ELECTRIC fields that 'reconnect' via the redirection of current.

What electric fields?

Come on Tim: ...

It was never my intention to question the presence or existence of electric fields. Since you said that the electric fields were reconnecting, I wanted you to identify the electric fields that are reconnecting. I still don't have a comprehensible answer to that question. You see, magnetic reconnection releases energy inside the plasma, and results in a strong and well observed change in the energy state of the magnetic field. But all the essence of what we get from you is this:

The anodes and cathodes are ultimately 'reconnecting' via the redirection of current

You're essentially trying to ignore the fact that you're ultimately "reconnecting" a couple of cathodes and anodes via the redirection of current.

This process you describe happens entirely outside the plasma. It involves the anodes and the cathodes, but has nothing to do with the transfer of energy internal to the plasma, which is key to magnetic reconnection. In short, it is not physically possible for the reconnection you describe to be in any way associated with the phenomena of magnetic reconnection.

The actual experiments begin and end with cathodes, anodes and ELECTRIC fields that 'reconnect' via the redirection of current.

I will also add that this is the case only for this experiment and those like it. However, this is not the case for instance with the Magnetic Reconnection facility, or any of the tokamak type magnetic reconnection experiments. So while you might take this course for this case, the claim is not generally applicable across the board.

 

[Michael Mozina]

It was never my intention to question the presence or existence of electric fields.

Then don't ask "What electric fields?".

Since you said that the electric fields were reconnecting, I wanted you to identify the electric fields that are reconnecting. I still don't have a comprehensible answer to that question.

Yes Tim, you do. I didn't give it to you, the authors of the paper gave it to you. They very clearly and meticulously explained how it works, down to the details of the physical process of current reconnection between the two current carrying filaments. They explained it clearly and logically too. They specifically noted that the current is deflected (J × B ) into the other current channel. There's no way they could have been any more clear about the fact that the currents are redirected between the two current filaments.

Since first reading Birn's paper on "reconnection", I had to accept the fact that one could in fact "dumb down" the math to the B orientation alone, but there are two electric fields reconnecting at the level of particle physics and current redirection.

You really did pick a "perfect" first experiment Tim, it's a pity you refuse to hear their words.

If you believe that this particular experiment is not indicative of the need for current to pull off the "reconnection" process, please provide us with a single published experiment that you believe best represents the process.

You're going to eventually have to cop to the fact that it can be viewed as "current reconnection" Tim, sooner or later. Alfven treated the whole filament as a single circuit, and treated the reconnecting region between them in terms of current carrying double layers. His 'method' of describing these double layer transaction is equally valid.

Even *assuming* you do come up with an experiment involving "reconnection" that doesn't require current first, you'll have to admit that at least *SOME* brands of 'reconnection" can be seen as a "current reconnection" between two current carrying filaments.

 

[Michael Mozina]

Tim, here's the deal......

Prior to 'reconnection' of the current, cathode C1 connects to anode A1, and cathode C2 connects to anode A2. After 'reconnection', cathode C1 connects to anode A2 and cathode C2 connects to anode A1. You electrically reconnected two cathodes and two anodes, and you're calling it 'magnetic' reconnection.

 

[GeeMack]

[...] and you're calling it 'magnetic' reconnection.

It is magnetic reconnection. That's what the objective quantitative empirical results of the experiment show. It simply is. It's not something else, some made up nonsense a bunch of crackpots are desperately trying to, but are unable to support. It's not some phenomenon that would be better named "circuit reconnection" and the entire community of physicists worldwide are just calling it magnetic reconnection. The reason they call it that is because it is that. It would be a glaring misinterpretation of the term, a ludicrous misunderstanding of the physics, or abject dishonesty (a lie) to claim it means something else.

So if there are no demonstrable problems with magnetic reconnection, other than some people don't know what it means so they detest the term and want to call it something else, maybe we can all agree and put this to rest. And if there are some problems with the physics of magnetic reconnection, after all these posts claiming there's a problem but not describing it like real scientists would do, objectively and quantitatively, maybe now would be a good time to do that.

 

[Michael Mozina]

It is (current) reconnection. That's what the objective quantitative empirical results of the experiment show.

There, I fixed that for you. The rest of your post is more denial and personal attack (as always). Why do you bother? Do you think *ANYONE* believes your attack the messenger garbage anymore? You have zero scientific credibility because you refuse to acknowledge that discharges occur in plasmas and that currents reconnect in plasma, and you won't touch the papers that demonstrate this fact with a ten foot pole. Worse yet, you run from every direct scientific question that is put to you.

Let me spell it out for you clearly, one more time. The problem with magnetic reconnection is that you're not reconnecting magnetic fields, you're reconnecting a couple of E fields, specifically two cathodes and two anodes via the redirection of current.

 

[Tim Thompson]

Electric currents and magnetic reconnection IV

Tim, here's the deal......

Prior to 'reconnection' of the current, cathode C1 connects to anode A1, and cathode C2 connects to anode A2. After 'reconnection', cathode C1 connects to anode A2 and cathode C2 connects to anode A1. You electrically reconnected two cathodes and two anodes, and you're calling it 'magnetic' reconnection.

There is nothing in the abstract (Lawrence & Gekelman, 2008) which supports this claim, no mention of any anode switching (and since there is only 1 anode anyway, how could there be a switch). But what does this have to do with the change in the internal energy state of the magnetic field inside the plasma?

I am spending the weekend at the Riverside Telescope Makers Conference, and therefore likely to disappear for long periods when free time suddenly vanishes.

 

[Michael Mozina]

There is nothing in the abstract (Lawrence & Gekelman, 2008) which supports this claim, ......

You're right, it was a "thought experiment".

The plasma currents are simply being "pinched" together in the first experiment you cited.