Magnetic reconnection and physical processes

[GeeMack]

What's the heating mechanism that allows the loops (individually) to reach millions of degrees and sustain that temperature for hours on end RC?

Well someone here is claiming to have the expertise to answer that...

The "circuit/resistor" approach explain that heating process quite nicely, [...]

So let 'er rip, Michael. Explain that heating process, quite nicely, with your "circuit/resistor" approach. Real physics, real math, quantitative values for current, resistance, thermal characteristics, etc. Oh, and no pretty looks-like-a-bunny pictures and none of those evil magic Mozina fairies you're always babbling about, okay?

 

[brantc]

But that is NOT what brantc is all about, he wants the loops to be created no under the photosphere.

When did I ever say that????????????????????????????????????????????

You must not recognize me......

The footprints of the loop ARE under the photosphere.....

The loops are 100eV iron atoms visible at 171 to 192nm.

The are "hot" because of electric field acceleration.

The heat is from the acceleration of the particles in an electric field, which then thermalize.

From the TRACE website.

"On the left (top) is a TRACE image taken on 9 August 1999, around 23:00 UT, in the 171Å passband (characteristic of 1 million degree gas; shown as the square root of the measure intensity). High-arching loops stand out, to a height of appriximately 120,000 km, visible along their entire length. The image on the right is a ratio of 195Å to 171Å, and serves as a measure of temperature. This image shows the loops as green along most of their length, demonstrating that the temperature varies little along them (which is why they can be seen in the 171Å image in the first place). The fact that the temperature is so nearly constant along the length requires that most of the heating is concentrated low down, in the bottom 15,000 km or so.

If the temperature does not vary much along aloop, and lies around 1 million degrees along most of its length, the gas should sag into the bottom of the loops under the influence of gravity. Consequently, the gas density should decrease by a factor of almost three every 50,000 km; the emission (which scales as the square of the density) should drop by that factor every 25,000 km. The right-hand bar in the lower image on the left shows how radidly the emission should have dropped off in the case of such simple gravitational stratification; the observed situation is closer to the intensity profile in the left-hand bar, for which the scale height has been doubled. Clearly, the emission drops off much more slowly than expected from a simple static model. The assumptions that are generally made that solar coronal loops are essentially stationary (evolving slow compared to the time they can adjust to a new situation) and that they are uniformly heated have been demonstrated to be fundamentally untenable: many loops evolve very rapidly, and none of them is heated uniformly!

 

[brantc]

The heating mechanism of a single coronal loop is the filling of the flux tube with coronal plasma. (Duh !).

The coronal heating problem is different. That is the problem that the temperature of the corona generally is millions of kelvins higher than that of the photosphere. There are many theories why this is so. The leading contenders are

• wave heating and
• magnetic reconnection in "microflares" in the photosphere.

So what heats the coronal(loops) plasma? Remember heating is the same as acceleration. The plasma goes from .6eV to 100eV(100 million degrees).

My guess would be electric fields across the flux tube/coronal loop(or from the photosphere to the corona) that accelerate the plasma from .6eV to 100eV..

These are the same electric fields responsible for electron beam/cathode ray observations.

 

[Reality Check]

Evidence that coronal loop plasma is heated by acceleration in an electric field

When did I ever say that????????????????????????????????????????????

You must not recognize me......

The footprints of the loop ARE under the photosphere.....

The loops are 100eV iron atoms visible at 171 to 192nm.

The are "hot" because of electric field acceleration.

The heat is from the acceleration of the particles in an electric field, which then thermalize.

From the TRACE website.

"On the left (top) is a TRACE image taken on 9 August 1999, around 23:00 UT, in the 171Å passband (characteristic of 1 million degree gas; shown as the square root of the measure intensity). High-arching loops stand out, to a height of appriximately 120,000 km, visible along their entire length. The image on the right is a ratio of 195Å to 171Å, and serves as a measure of temperature. This image shows the loops as green along most of their length, demonstrating that the temperature varies little along them (which is why they can be seen in the 171Å image in the first place). The fact that the temperature is so nearly constant along the length requires that most of the heating is concentrated low down, in the bottom 15,000 km or so.

If the temperature does not vary much along aloop, and lies around 1 million degrees along most of its length, the gas should sag into the bottom of the loops under the influence of gravity. Consequently, the gas density should decrease by a factor of almost three every 50,000 km; the emission (which scales as the square of the density) should drop by that factor every 25,000 km. The right-hand bar in the lower image on the left shows how radidly the emission should have dropped off in the case of such simple gravitational stratification; the observed situation is closer to the intensity profile in the left-hand bar, for which the scale height has been doubled. Clearly, the emission drops off much more slowly than expected from a simple static model. The assumptions that are generally made that solar coronal loops are essentially stationary (evolving slow compared to the time they can adjust to a new situation) and that they are uniformly heated have been demonstrated to be fundamentally untenable: many loops evolve very rapidly, and none of them is heated uniformly!

A nitpick: The footprints of a coronal loop are considered to be in the photosphere rather than under it. The coronal loop of course continues under the photosphere.

You missed a link to the actual TRACE page and the fact that it does not mention that the iron atoms (or the plasma in general) "are "hot" because of electric field acceleration".


So as well as:

1. Source for flux tube is formed by the energy of the particles flowing through it
2. Please cite your source for your assertion that all flux tubes contain plasma

we now have:
First asked 9 February 2010
brantc,
What is your evidence that the plasma in a coronal loop is heated by the acceleration of the particles in an electric field, which then thermalize?

 

[brantc]

A nitpick: The footprints of a coronal loop are considered to be in the photosphere rather than under it. The coronal loop of course continues under the photosphere.

You missed a link to the actual TRACE page and the fact that it does not mention that the iron atoms (or the plasma in general) "are "hot" because of electric field acceleration".


So as well as:

1. Source for flux tube is formed by the energy of the particles flowing through it
2. Please cite your source for your assertion that all flux tubes contain plasma

1. Common sense derived from the idea that flux tubes follow the right hand rule.

2. See number one above.

And these are derived from magnetic field measurements at LAPD.
http://plasma.physics.ucla.edu/images/gallery/2jchan.jpg
http://plasma.physics.ucla.edu/pages/gallery.html#

Every "flux tube" in the lab has a plasma inside of it.

As I said before your mathematical model can be defined any way you want but if it is describing a real entity then it must follow certain rules.

I have never seen a twisted "magnetic tube" made with magnets, or electromagnets if you prefer, with no plasma in the laboratory.

we now have:
First asked 9 February 2010
brantc,
What is your evidence that the plasma in a coronal loop is heated by the acceleration of the particles in an electric field, which then thermalize?

Lets just fix this right now. I have no sources for anything I say. I'm coming up with plausible ideas on how something might be accomplished based on simple physics and laboratory experiments.

If you disagree then you say "Electric fields dont exist that create the electron beam because......." and you state your reason based on 'basic' physics.


Me:
Electron beams have been observed therefore there must be an electric filed with a "potential" across it. That is basic science no matter where you observe it.

Electron beams have been observed therefore an electric field must exist from the base of the electron beam(photosphere) to the top of the electron beam(corona).

These electron beams have been observed in the same vicinity across the same distance as the electrons(ions) that heat up on their way to the corona.

And this (electric field) must also heat the electrons and ions that reach the corona from the photosphere.

That is how you come up with a hypothesis from basic principles.

Birkelands Terella demonstrated some of these same observations.

As far as arcades on the solar surface there are 2 different polarities that are closely spaced on the solar surface. That produces an electric field between 2 solar surface locations leading to a current flowing flux tube.

This new picture shows the difference between solar surface flux tubes and laboratory/ magnetotail flux tubes.

Look at the center of this picture.
http://trace.lmsal.com/POD/images/T171_20091231_0703.jpg
Notice the helical structure going from left to right. Look closely notice how one set of filaments in twisting left and the other one is twisting right.
The most interesting thing is, and I mentioned this to Tusenfem years ago, is that the 2 structures are nested.
Also notice the individual "strands". There are movies of these structures moving and they are moving opposite directions one inside the other.

I have not come up with a plausible idea on why the difference between flux tubes. But those are the observations.

And I will post this one just in case you didnt read my earlier post.
http://trace.lmsal.com/POD/images/T171_990809_230034_bar_clip.gif

 

[GeeMack]

Lets just fix this right now. I have no sources for anything I say.

You fixed it.

 

[Reality Check]

Source for all flux tubes in the lab contain plasma

1. Common sense derived from the idea that flux tubes follow the right hand rule.

1. Wrong physics derived from the assumption that all flux tubes in existence (e.g. on the Sun) contain plasma.

2. See number one above.

2. See number one above.

And these are derived from magnetic field measurements at LAPD.
http://plasma.physics.ucla.edu/images/gallery/2jchan.jpg
http://plasma.physics.ucla.edu/pages/gallery.html#

Argument from pretty pictues is really bad tactics - it puts you in the camp of cranks like Micheal Mozina.

Every "flux tube" in the lab has a plasma inside of it.

So now we have

1. Source for flux tube is formed by the energy of the particles flowing through it
   An idea that you have?
2. Please cite your source for your assertion that all flux tubes contain plasma
   Another idea that you have?
3. Evidence that coronal loop plasma is heated by acceleration in an electric field
   No source (and no evidence?)

And ...
First asked 9 February 2010
brantc,
What sources do you have that all flux tubes in the lab contain plasma?

As I said before your mathematical model can be defined any way you want but if it is describing a real entity then it must follow certain rules.

The rules are that the mathematical model has to match the laws of physics (magnetic reconnection does) and the observations (magnetic reconnection mostly does)

Lets just fix this right now. I have no sources for anything I say. I'm coming up with plausible ideas on how something might be accomplished based on simple physics and laboratory experiments.

You are coming up with ideas. They are implausable, e.g. flux tubes on the Sun cannot be created from the plasma flowing through them as tusenfem (who knows much more about this than me) has stated.

This is my rough guess as to why:
You are thinking about the magnetic fields from from the electric current in a wire. In that case there is a magnetic filed (a "flux tube" - but no plasma!) around the wire because the current is physically contrained to the wire. The right hand rule gives you the magnetic field around a current in a wire.
A plasma is different. Any flow of charges in a plasma is not constrained to move like elecrons in a wire. The magnetic field generated by that flow will exert a force on the carriers and change its direction. That will disrupt the flow and the magnetic field will no longer exist.

Look at the center of this picture.
http://trace.lmsal.com/POD/images/T171_20091231_0703.jpg
Notice the helical structure going from left to right. Look closely notice how one set of filaments in twisting left and the other one is twisting right.
The most interesting thing is, and I mentioned this to Tusenfem years ago, is that the 2 structures are nested.
Also notice the individual "strands". There are movies of these structures moving and they are moving opposite directions one inside the other.

More arguments from pretty pictures. You need to do what astronomers actually do and analyze the image to see what is happening.

 

[brantc]

And still you have not explained to us how the plasma suddenly decides to make these big flux tubes in your "theory" of electrons flowing "straight" and "gyrating around a field that still needs to be created" etc. etc.

Look at this diagram. If these are the magnetic field lines, what was the electron motion required to create each of the lines??
http://upload.wikimedia.org/wikipedia/commons/thumb/7/79/Magnetic_rope.png/300px-Magnetic_rope.png

Originally Posted by brantc View Post
The thing that blows me away is how as soon as you get into space you say the mechanism completely changes

But that is the problem, we DON'T say the mechanism completely changes. However, you have to look at the situation that you are looking at. In the lab it is easiest to create two flux ropes, with initial parallel field (as there is only one magnetic field generator). Then a voltage is applied and currents start to flow and two flux ropes are produced, which attract because of parallel currents. Then the two ropes get together and can touch and have oppositely directed field at the touching point. And this can lead to reconnection (although also a bouncing phenomenon has been noted Intrator et al., 2009, without reconnection).

What I mean by this is that in the lab the flux tubes are driven by current flow, out of necessity I might add, thats what flux tubes do..
Shut off the current the tube goes away.

When you get to the sun your mechanism says that no longer are electric currents the cause for the flux tube but that the flux tube drives the plasma through by magnetism, not the electric fields at the ends of the tube. And it is the magnetic field that is poking through the photosphere and twisting that actually causes the shape of the flux tubes.

I'm saying that the helical shape of the flux tube is due to the right hand rule like in the lab.

Here is a paper by Semenov et al. (2009) about PIC and comparisons with analytical theory, which cites this list of papers where you certainly will find whatever your heart desires. And as Annales Geophysicae is open, you can even download the paper for free.

<snip>
However, non-ideal effect which breaks the frozen-in condition of magnetic field is needed for the excitation of magnetic reconnection in a collisionless plasma. A number of theoretical and simulation studies have disclosed that there exist two types of triggering mechanisms which break the frozen-in condition and lead to magnetic reconnection in a collisionless plasma. One is due to the wave-particle interaction which is a cause of anomalous resistivity in the current sheet [1-3]. The other is due to the particle kinetic effect which becomes significant in a particle scale such as the collisionless skin depth and the Larmor radius [4,5].
<snip>
Comment: We know that plasma is not really a perfect conductor(frozen in fields). It just get that treatment because its easier to deal with??
<snip>
It is found that the interaction between this EM wave and charged particles carrying the equilibrium current can be a cause of an anomalous resistivity leading to collisionless reconnection in the neutral sheet.
If an external driving flow exists, collisionless reconnection is triggered by the particle kinetic effect earlier than the excitation of the EM instability.
<snip>
http://www.jspf.or.jp/JPFRS/PDF/Vol2/jpfrs1999_02-058.pdf

What they are saying is that if there is an electric current(particle kinetic effect) then this will be the dominant mechanism in triggering a reconnection.

The only issue with this paper is that it doesnt use the flux tube model. Although flux tube could be considered to have current sheets, the geometry is wrong, same as 99% of all the other 2D PIC simulations

 

[brantc]

Argument from pretty pictues is really bad tactics - it puts you in the camp of cranks like Micheal Mozina.

You dont seem to think that magnetic fields exist around a flux tube that follow the right hand rule. I showed you a picture that clearly showed that is the case from a reputable source.

Are you being difficult just to be difficult? Do you ever do original science???

Here is the paper.
http://plasma.physics.ucla.edu/papers/Budapest_paper.pdf

On page 8 can you see the diagram that shows the vector field measurements??? Its for an Argon plasma???

Do those vectors follow the right hand rule??

From that paper.
"Data of the vector wave magnetic field was acquired on 15 planes with their normal parallel to the background magnetic field. Data at 2048 time steps ( δt =400 ns ) and 1025 locations, spaced 1 cm apart on a rectangular grid, was acquired on each plane. An example is shown in figure 3. Unlike the patterns from a disk exciter, there are clearly two current channels roughly 4 cm in diameter and 12.6 cm apart. The wave fills almost the entire plasma column in a plane orthogonal to B0. The largest wave magnetic in the volume is was 1.6 Gauss, which corresponds to (equations NO-Tex). The pattern is intriguing because, when viewed in time, it appears to be a rotating spiral."


Is that what you want????????????????????



Page 9.
"The pattern in Helium is much more complex and consists of a higher m mode 9 involving up to five current channels. These patterns will be discussed in far more detail in a future publication."

I wonder if Hydrogen has a greater number of channels like on the sun in the picture I posted.

 

[Reality Check]

Did you notice the absence of the words flux and tube in the paper

You dont seem to think that magnetic fields exist around a flux tube that follow the right hand rule. I showed you a picture that clearly showed that is the case from a reputable source.

That is silly brantc.

• A flux tube by definition is just magnetic fields. There is nothig to apply the right hand rule to.
• A flux tube filled with plasma will have an additional magnetic field generated in it according to the right hand rule and the electric current.
• Electric current in a plasma cannot create a flux tube as tusenfem (who knows much more about this than me) has stated.
  This is my rough guess as to why:
  You are thinking about the magnetic fields from from the electric current in a wire. In that case there is a magnetic field (a "flux tube" - but no plasma!) around the wire because the current is physically contrained to the wire. The right hand rule gives you the magnetic field around a current in a wire.
  A plasma is different. Any flow of charges in a plasma is not constrained to move like electrons in a wire. The magnetic field generated by that flow will exert a force on the carriers and change its direction. That will disrupt the flow and the magnetic field will no longer exist.

You showed me a picture with no caption and no explanation.
The actual caption is:

Upper plate: Streamlines (in the perpendicular plane) of the wave magnetic field of two interacting shear Alfvén waves, along with isosurfaces of the axial current density.
Lower plate: Close up of the instantaneous wave magnetic field vectors for the indicated plane.
The plasma source (a heated, oxide-coated cathode) is visible in the upper, right-hand corner of the image

Are you being difficult just to be difficult? Do you ever do original science???

No. Yes - in my short university career. That is why I am so hard on you with your vague ideas. I know how science is done (e.g. data->hypothesis->model->predictions->back to data).
This is a science forum. I would expect a bit of actual science from you.

Here is the paper.
http://plasma.physics.ucla.edu/papers/Budapest_paper.pdf

Experimental Measurements of the Propagation of Large Amplitude Shear Alfven Waves

First asked 9 February 2010
brantc,
Did you notice the absence of the words flux and tube in the paper?

The experimental setup makes it clear to me (but I come from a theoretical physics background) that they are generating Alfvén waves in the plasma as in the title and many other clues in the paper, e.g. Fig 5: "Currents of a shear Alfvén wave launched by a helical antenna".

 

[Reality Check]

<snip>
However, non-ideal effect which breaks the frozen-in condition of magnetic field is needed for the excitation of magnetic reconnection in a collisionless plasma. A number of theoretical and simulation studies have disclosed that there exist two types of triggering mechanisms which break the frozen-in condition and lead to magnetic reconnection in a collisionless plasma. One is due to the wave-particle interaction which is a cause of anomalous resistivity in the current sheet [1-3]. The other is due to the particle kinetic effect which becomes significant in a particle scale such as the collisionless skin depth and the Larmor radius[4,5].
<snip>
Comment: We know that plasma is not really a perfect conductor(frozen in fields). It just get that treatment because its easier to deal with??

You are mistaken in thinking that plasma is treated as a perfect conductor. That the ideal MHD approximation as first described by Alfven. This is valid in many (but not all) astrophysical situations. Sunspots have diffusion times measured in thousands of years. Magnetic reconnection cannot happen in an ideal MHD plasma because the topology of the magnetic field cannot change (the field is frozen in).
See for example Resistive MHD

Resistive MHD describes magnetized fluids with finite electron diffusivity (

). This diffusivity leads to a breaking in the magnetic topology; magnetic field lines can 'reconnect' when they collide. Usually this term is small and reconnections can be handled by thinking of them as not dissimilar to shocks; this process has been shown to be important in the Earth-Solar magnetic interactions.

<
<snip>
It is found that the interaction between this EM wave and charged particles carrying the equilibrium current can be a cause of an anomalous resistivity leading to collisionless reconnection in the neutral sheet.
If an external driving flow exists, collisionless reconnection is triggered by the particle kinetic effect earlier than the excitation of the EM instability.
<snip>
http://www.jspf.or.jp/JPFRS/PDF/Vol2/jpfrs1999_02-058.pdf

What they are saying is that if there is an electric current(particle kinetic effect) then this will be the dominant mechanism in triggering a reconnection.

You missed out that it is a trigger for magnetic reconnection - the thing that you seem say does not happen and needs to be replaced by your idea.

 

[tusenfem]

When did I ever say that????????????????????????????????????????????

You must not recognize me......

The footprints of the loop ARE under the photosphere.....

Well, that's how it sounded to me, a few pages ago, when you were talking about "what creates the magnetic field of the loop" which, according to you, were "the electrons flowing along the tube" and the you came up with the electrons "some going straight and some gyrating" etc. etc.

ETA: and this would be the post I was thinking of

The loops are 100eV iron atoms visible at 171 to 192nm.

The are "hot" because of electric field acceleration.

To nitpick, no, the are hot because of coulomb collisions.

The heat is from the acceleration of the particles in an electric field, which then thermalize.

indeed

 

[brantc]

Originally Posted by Reality Check
"A flux tube filled with plasma will have an additional magnetic field generated in it according to the right hand rule and the electric current."

Ok. That is the terminology I will use from now on. Can we move forward?

So there you go. A parallel magnetic field and a curl magnetic field.
Parallel from external source. Curl from particle motion in the parallel direction.

And I bet there is a component(particle motion) that represents the classic Birkeland current/magnetic rope/plasma filled flux tube/rotating elephant trunk, etc.
Plus I would think that the gyro motion of the electron reinforces the parallel component.
http://www.plasma-universe.com/images/thumb/f/f1/Magnetic-rope.gif/300px-Magnetic-rope.gif

But I would still like to see a real physical flux tube with no plasma in it.
Where can I find one??

 

[brantc]

Originally Posted by brantc View Post
The loops are 100eV iron atoms visible at 171 to 192nm.

The are "hot" because of electric field acceleration.

To nitpick, no, the are hot because of coulomb collisions.

Is this more correct?

They are thermalized(random kinetic energy) because of coulomb collisions(heat energy in a specific area).

They are hot(velocity in eV, kinetic energy) because they are accelerated from .6eV to 100eV(6000K to 1million K).

Hot vs heat.

 

[GeeMack]

I'd really like to hear your explain how a single coronal loops reaches millions, sometimes tens of millions of degrees Kelvin over a 6000 K photosphere. The "circuit/resistor" approach explain that heating process quite nicely, but you seem to have no way to explains that heating process via "magnetic reconnection', unless you've claiming the loop is "magnetically reconnecting" within itself!

Okay. Go for it. Do something you've never done in all your years. Explain it quite nicely using the "circuit/resistor" approach, quantitative, like real science. No pretty pictures allowed. You have an opportunity here to show people that you're not in grade school anymore. Show your work.

Okay, so you can't explain it quite nicely using the "circuit/resistor" approach. Just another in the long list of crackpot notions you claim you can support, yet when called on to put up or shut up, you shut up.

 

[Reality Check]

Ok. That is the terminology I will use from now on. Can we move forward?

So there you go. A parallel magnetic field and a curl magnetic field.
Parallel from external source. Curl from particle motion in the parallel direction.

No we do not go. We do not have a parallel magnetic field. We have

• A magnetic flux tube from an external source
• Another magnetic from the current in the plasma that is in the flux tube.

But I would still like to see a real physical flux tube with no plasma in it.
Where can I find one??

On the Sun.
However I do not know of any observations of totally empty flux tubes.
There are observations of plasma moving into them. What happens is that coronal loops are observed to become visible and then brighten.
A Brightening Coronal Loop Observed by TRACE. II. Loop Modeling and Constraints on Heating

We work under the hypotheses that (a) initially the plasma in the loop is not at coronal temperatures (T ~10⁶ K) and the loop is almost empty, since it is totally invisible to TRACE at the beginning of the observation; and (b) its brightening is caused by the transient release of heating somewhere inside it, which leads the plasma temperature in the range of TRACE sensitivity and increases the emission measure by driving evaporation of plasma from the chromosphere

 

[Zeuzzz]

Okay, so you can't explain it quite nicely using the "circuit/resistor" approach. Just another in the long list of crackpot notions you claim you can support, yet when called on to put up or shut up, you shut up.

A more constructive way to approach this is to ask MM what the "circuit/resistor" approach is and what are his sources. Or you just come across as a rather annoying loudmouth.

Not sure if this is relevant to michaels line of argument (think he's using the alfven current disruption model which is slightly different) but I would like you comment on your thoughts about using the magnetic field or electric current as primary.

I'll even start you off with something to chew on Geemack. Whats your thoughts on this publication for example? I recommend this for some background.

http://www.agu.org/pubs/eos-news/supplements/1995-2003/010093e.shtml

Recently, John Greene took up the "Parker Challenge" [Parker, 1996]. Parker argued that the correct approach to understanding magnetospheric phenomena is to use the magnetic field and plasma flow velocity (B, u) as the primary quantities, with the electric field and current (E, j) being secondary, in that E and j can be determined from B and u. At the outset, it should be noted that this is strictly true only if the plasma dynamics are entirely governed by ideal magnetohydrodynamics.

The correct approach to understand magnetospheric physics depends on the phenomenon to be investigated. There is no single paradigm that is always superior to others for treating macroscopic magnetospheric problems. Insisting on one particular approach as the only correct one is unjustified and may stifle innovative pursuit in research. Thus, I am motivated to address both the limitations of the B-u paradigm, and the merits of the E-j paradigm.

Parker [1996] equated the B-u paradigm with the magnetohydrodynamics (MHD) approach as he stated that "the macroscopic behavior...of the magnetosphere is described by MHD which we refer to here as the B-u paradigm. The equations of MHD form a complete set of partial differential equations, providing a deductive approach to the theory of magnetospheric activity." Numerical simulations of the magnetosphere based on the MHD equations have indicated magnetospheric disturbances to be solely driven by X-type magnetic reconnection in various regions. This may be thought of as vindication of the B-u paradigm, but as we discuss below there is strong evidence for suggesting that MHD is insufficient to explain the physics of such disturbances.

What then is the E-j paradigm, where electric field and current are taken to be the primary quantities? What it is not is an electrical circuit approach. Rather, a focus on electric field and current as primary quantities generally requires an analysis based on particle dynamics. Therefore, we shall associate the E-j paradigm as the approach of single particle calculation or kinetic analysis (with full consideration of collective effects). The single particle approach is valid when the collective behavior of the plasma under consideration is relatively unimportant. The heart of this approach is the Boltzmann equation or the Vlasov equation in the collisionless regime. It should be recognized that the MHD equations can be derived from the Vlasov equation by adopting certain approximations, much like the classical equations in Newtonian mechanics can be obtained from the special relativity equation when the speed is small relative to the light speed.

The E-j approach is useful to treat many macroscopic magnetospheric problems that cannot be explained with the B-u approach. Injection of particles in the inner magnetosphere during magnetospheric substorms is a prime example of this. Substorm injection produces clear velocity dispersion over a large region in the inner magnetosphere, leading to the recognition of the injection boundary and the inference on the location of the particle source [McIlwain, 1974].

Mounting evidence now points to the cause of a magnetospheric substorm to be a culmination of one or more physical processes occurring over multiple localized sites with intermittent disturbances rather than the consequence of a single large-scale one as once thought. Thus, substorms are analogous to terrestrial thunderstorms. Both phenomena are basically an electric discharge of the system, involving transient and localized disturbances, and yet their effects spread over regions substantially larger than that of these local discharges. The culmination of these disturbances gives the appearance of a large-scale phenomenon. This early conceptual picture presented in 1988 and documented later in 1991 [Lui, 1988, 1991] fits well with the later development of forced and/or self-organized criticality concept [Chang, 1992; Consolini, 1997]. In fact, the magnetosphere exhibits both sudden changes of state resembling the first order phase transitions and more gradual ones resembling the second order phase transitions. The system evolution in these situations calls for yet another approach, such as the renormalization group [Chang, 1992].

When compelling evidence points to the localization of these disturbances, it is postulated that the responsible process is localized magnetic reconnection. Unfortunately, this conjecture is not held up by two independent three-dimensional numerical simulations of magnetic reconnection. Pritchett and Coroniti [2000] used kinetic simulation to show magnetic reconnection in the tail plasma sheet to be essentially two-dimensional even when localized forcing is imposed at the tail magnetopause. Drake et al. [2000], also using kinetic simulation, have found magnetic reconnection to evolve quickly to a two-dimensional configuration even when it is initiated in a three-dimensional geometry. There are MHD simulations that yield localized magnetic reconnection, either intentionally by imposing arbitrarily localized resistivity or by non-physical numerical artifacts. The validity of these results is very much in question.

There are many limitations of the B-u paradigm and merits of the E-j paradigm which I shall not elaborate further here. Interested readers may find a more extensive discussion on these issues in Lui [2000], which includes also a discussion on the similarities and differences between current disruption and magnetic reconnection. In summary, however, the main objection to the B-u paradigm is its reliance on magnetohydrodynamics, when many of the processes occurring in the magnetosphere are inherently kinetic, requiring an approach that can better be summed up as the E-j paradigm.

Do you think that more things are explained when considering currents and the particles that make them, or bu and magnetic field lines?

 

[Reality Check]

http://www.agu.org/pubs/eos-news/supplements/1995-2003/010093e.shtml

GeeMack
A few points

• The highlighting of the last 2 paragraphs were added for some reason by Zeuzzz.
• The supplement and papers that it refers to are about magnetospheric physics, i.e. the interaction of the solar wind with planetary magnetic fields, especially the Earth's. I suspect that there are plenty of situations in this field where the E-j paradigm is more appropriate than the B-u paradigm.
• The supplement has little do do with this thread. It does not state that magnetic reconnection does not happen or does not release energyor if energy is released then how that energy is released.

 

[GeeMack]

A more constructive way to approach this is to ask MM what the "circuit/resistor" approach is and what are his sources. Or you just come across as a rather annoying loudmouth.

Michael claimed to he was able to quite nicely explain how a single coronal loop reaches millions, sometimes tens of millions of degrees Kelvin over a 6000 K photosphere using the "circuit/resistor" approach. I know you and he think people are loudmouths when they actually call you guys on your crackpottery. But in the real world where real science is done, if you can't explain it, maybe you're better off not claiming you can. Michael can't explain it. But he's pretty darn quick to whine about it when someone asks him to, isn't he?

As long as you truly believe you have a theory of physics that explains reality better than the generally accepted consensus, and since you haven't been able to make your case compelling enough to get any professional physicist on board to help you actually flesh out your conjectures, you've got an awful lot of work to do.

 

[The Man]

A more constructive way to approach this is to ask MM what the "circuit/resistor" approach is and what are his sources. Or you just come across as a rather annoying loudmouth.

Not sure if this is relevant to michaels line of argument (think he's using the alfven current disruption model which is slightly different) but I would like you comment on your thoughts about using the magnetic field or electric current as primary.

I'll even start you off with something to chew on Geemack. Whats your thoughts on this publication for example? I recommend this for some background.

http://www.agu.org/pubs/eos-news/supplements/1995-2003/010093e.shtml



Do you think that more things are explained when considering currents and the particles that make them, or bu and magnetic field lines?

How about the examples of magnetic reconnection that I have given using just magnets? I don’t think it is a matter of quantity of things explained by magnetic field lines, but more the ease by which that explanation can be understood and used. Certainly when considering magnets and their magnetic fields, their interactions and in the examples I have given reconnections, the magnetic field lines do the explaining and exemplifying most effectively.