Discovery of Saturn’s auroral heartbeat
An international team of scientists led by Dr Jonathan Nichols of the University of Leicester has discovered that Saturn’s aurora, an ethereal ultraviolet glow which illuminates Saturn’s upper atmosphere near the poles, pulses roughly once per Saturnian day.
The length of a Saturnian day has been under much discussion since it was discovered that the traditional ‘clock’ used to measure the rotation period of Saturn, a gas giant planet with no solid surface for reference, apparently does not keep good time.
Saturn, like all magnetised planets, emits radio waves into space from the polar regions. These radio emissions pulse with a period near to 11 h, and the timing of the pulses was originally, during the Voyager era, thought to represent the rotation of the planet. However, over the years the period of the pulsing of the radio emissions has varied, and since the rotation of a planet cannot be easily sped up or slowed down, the hunt for the source of the varying radio period has become one of the most perplexing puzzles in planetary science.
Now, in a paper to be published in Geophysical Research Letters (August 6), Nichols et al. use images from the NASA/ESA Hubble Space Telescope of Saturn’s auroras obtained between 2005-2009 to show that, not only do the radio emissions pulse, but the auroras beat in tandem with the radio.
Dr Nichols said: “This is an important discovery for two reasons. First, it provides a long-suspected but hitherto missing link between the radio and auroral emissions, and second, it adds a critical tool in diagnosing the cause of Saturn’s irregular heartbeat.”
Auroras, more commonly known as the “northern lights” on Earth, are caused when charged particles in space are funnelled along a planet’s magnetic field into the planet’s upper atmosphere near the poles, whereupon they impact the atmospheric particles and cause them to glow. This happens when a planet’s magnetic field is stressed by, for example, the buffeting from the stream of particles emitted by the Sun, or when moons such as Enceladus or Io expel material into the near-planet space.
Saturn’s radio waves were long suspected to be emitted by the charged particles as they hurtle toward the poles, but no radio-like pulsing had been observed in Saturn’s aurora, an enigmatic disconnect between the two supposedly-related phenomena.
However, Nichols et al. found that by using the clock of the radio pulsing to organise the auroral data, and stacking the results from all the Hubble Saturn auroral images obtained from 2005-2009 on top of each other, the auroral pulsing finally revealed itself.
Dr Nichols added: “This confirms that the auroras and the radio emissions are indeed physically associated, as suspected. This link is important, since it implies that the pulsing of the radio emissions is being imparted by the processes driving Saturn’s aurora, which in turn can be studied by the NASA/ESA spacecraft Cassini, presently in orbit around Saturn. It thus takes us a significant step toward solving the mystery of the variable radio period.”
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This is the assertion:
“When one makes a side-by-side comparison & analysis of the peer-reviewed papers purporting to describe “magnetic reconnection” with peer-reviewed papers describing Electric Double Layers, it is clear that both these sets of papers are describing one and the same event or dyanamic: Electric Double Layers.”
I’ve seen no detailed attempt from Dr. Svalgaard to distinguish the two processes based on the observations & measurements of the relevant physical data.
But that may not be necessary because NASA has a mission in the works to empirically observe & measure the physical event in question:
From NASA:
“NASA is going to launch a mission to get to the bottom of the mystery [of what physical processes drive the event in question]. It’s called MMS, short for Magnetospheric Multiscale Mission, and it consists of four spacecraft which will fly through Earth’s magnetosphere to study reconnection [Electric Double Layer] in action. The mission passed its preliminary design review in May 2009 and was approved for implementation in June 2009. Engineers can now start building the spacecraft.”
http://science.nasa.gov/science-news/science-at-nasa/2009/31aug_mms/
In the 1940’s, when the concept of “magnetic reconnection” was formulated, electric fields were not considered (one must question the adequacy of a theory which failed to address such an important physical factor as electric fields) . But with the Magnetospheric Multiscale Mission, electric fields will be considered, and, indeed, the electric fields will be empirically observed & measured in tandem with magnetic fields and the flows of free electrons & ions.
I am confident that when detailed surveys are completed of the component parts, i.e., electric fields, magnetic fields, free electron & ion flow, and acceleration of charged particles, those surveys will reveal the structure, dynamics, and morphology consistent with Electric Double Layers.
(Already, satellite probes have surveyed so-called “magnetic reconnection” events in space, and those surveys revealed dynamics which were consistent with the Electric Double Layer process.)
It’s not the name or label that matters, it is the actual physical dynamics that count.
James F. Evans says:
August 8, 2010 at 9:49 am
I’ve seen no detailed attempt from Dr. Svalgaard to distinguish the two processes based on the observations & measurements of the relevant physical data.
No need to as they are different in their very definition:
Double layers occur between regions containing opposite electric charges, while reconnection happens between regions of opposite magnetic polarities. Reconnection is a topological rearrangement of magnetic field that converts magnetic energy to plasma kinetic energy.
But that may not be necessary because NASA has a mission in the works to empirically observe & measure the physical event in question
Magnetic reconnection has been studied in the laboratory since the 1960s
James F. Evans says:
August 8, 2010 at 9:49 am
I am confident that when detailed surveys are completed of the component parts
The index of a modern text book:
‘Magnetic Reconnection in Plasmas’ by Dieter Biskamp
Max-Planck-Institut für Plasmaphysik, Garching, Germany
Cambridge Monographs on Plasma Physics (No. 3)
Online Publication Date: December 2009
does not contain an entry on electric double layers.
Dr. Svalgaard presented Evans’ statement:
“I’ve seen no detailed attempt from Dr. Svalgaard to distinguish the two processes based on the observations & measurements of the relevant physical data.”
And Dr. Svalgaard responded: “No need to as they are different in their very definition: Double layers occur between regions containing opposite electric charges, while reconnection happens between regions of opposite magnetic polarities. Reconnection is a topological rearrangement of magnetic field that converts magnetic energy to plasma kinetic energy.”
No, actually Electric Double Layers and “magnetic reconnection” are the same event.
Dr. Svalgaard states: “reconnection happens between regions of opposite magnetic polarities.”
When two bodies of moving plasma come into contact, each body of plasma, free electrons & ions, has its own magnetic field caused by the motion of the plasma. Many times these bodies of plasma have opposite polarities. Upon contact of the magnetic fields, the magnetic fields are compressed and the plasma begins to self-organize, where “regions containing opposite electric charge”, free electrons & ions, form. Then the electrons & ions are accelerated in opposite directions out “exhaust jets” from the “event” location.
The “event” is not simply the contact of magnetic fields, but also, the interaction of electric fields, both emanated from the flowing “electrified particles”, it is the process of self-organization and the resultant organization & structure of the electrons & ions and their electric & magnetic fields which cause free electrons & ions to be accelerated in opposite directions.
So-called “magnetic reconnection” (Electric Double Layers) incorporates a series of events ultimately causing particle acceleration.
Dr. Svalgaard stated: “Reconnection is a topological rearrangement of magnetic field that converts magnetic energy to plasma kinetic energy.”
Yes, there is a “topological rearrangement” of magnetic fields, but that is due to the movement and structure of the free electrons & ions. Magnetic fields are creatures of the movement of the charged particles.
The “X” cross section that is part of the morphology of so-called “magnetic reconnection” is actually caused by crossed electric and magnetic fields as quantitatively described in the Electric Double Layer process.
Dr. Svalgaard wrote: “Magnetic reconnection has been studied in the laboratory since the 1960s”
Well, apparently, there are still many unanswered questions.
From “Basics of Magnetic Reconnection” which Dr. Svalgaard linked previously in the thread:
“While its effects are seen both near and far from home, reconnection is still poorly understood, making it one of the most important problems in plasma physics today.”
So, not only does NASA acknowledge “magnetic reconnection” is not understood, but so does the very paper Dr. Svalgaard linked to — his evidence.
More from the paper:
“Plasma physics is an often controversial field, possibly due to its complexity, and debates over mechanisms for reconnection are far from settled.”
“Classical reconnection theories require the poorly understood assumption of anomalous resistivity in order to achieve physically reasonable time scales, but a new theory based on decoupling of the electron and ion flows gives very promising results.”
Ah, it seems they are getting warmer when they consider “electron and ion flows”.
(But they are not there yet, as the paper studiously avoids mention of electric fields and the electric field’s effect on the overall process.)
From the paper:
V . CONCLUSION
“As a theory, magnetic reconnection is still undergoing revolutionary changes…There is still much to be learned however, and certainly more experimental study of reconnection in natural processes is necessary.”
http://www.phys.washington.edu/users/sharpe/486/schillacif.pdf
Doesn’t sound like scientists know as much about so-called “magnetic reconnection” as Dr. Svalgaard would have readers believe.
Perhaps, there is so much not understood about “magnetic reconnection” because the concept is faulty and inadequate to properly analyze & interpret the physical event at issue.
On the other hand, the Electric Double Layer concept has the quantitative framework necessary to consider all the applicable forces and particles, i.e., electric fields, magnetic fields, and the motions of free electrons and ions.
A double layer paper: Filamentary Structures in U-Shaped Double Layers, 2005:
“Observations from the Polar and FAST satellites have revealed a host of intriguing features of the auroral accelerations processes in the upward current region (UCR). These features include: (i) large-amplitude parallel and perpendicular fluctuating as well as quasi-static electric fields in density cavities, (ii) fairly large-amplitude unipolar parallel electric fields like in a strong double layer (DL), (iii) variety of wave modes, (iv) counter-streaming of upward going ion beams and downward accelerated electrons, (v) horizontally corrugated bottom region of the potential structures (PS), in which electron and ion accelerations occur, (vi) filamentary ion beams in the corrugated PS, and (vii) both upward and downward moving narrow regions of parallel electric fields, inferred from the frequency drifts of the auroral kilometric radiations.”
http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2005AGUFMSM41C1202D&db_key=AST&data_type=HTML&format=&high=42ca922c9c05019
By the way, there are plenty of plasma scientists that are familiar with Electric Double Layers:
James F. Evans says:
August 8, 2010 at 6:01 pm
And Dr. Svalgaard responded: “No need to as they are different in their very definition: Double layers occur between regions containing opposite electric charges
http://en.wikipedia.org/wiki/Double_layer_(plasma)
“A double layer is a structure in a plasma and consists of two parallel layers with opposite electrical charge”
“while reconnection happens between regions of opposite magnetic polarities. Reconnection is a topological rearrangement of magnetic field that converts magnetic energy to plasma kinetic energy.”:
http://www.phys.washington.edu/users/sharpe/486/schillacif.pdf
(also no mention of Double Layers)
Enough said.
James F. Evans says:
August 8, 2010 at 6:01 pm
By the way, there are plenty of plasma scientists that are familiar with Electric Double Layers:
I’m one. I have discussed this often with Hannes Alfven. It is quite clear what the concepts are. That you don’t get it is your problem. Now, you avoided to answer my question about what generates the Sun’s energy. So, now is another chance…
Dr. Svalgaard:
It does not surprise me that a so-called “magnetic reconnection” paper would not mention Electric Double Layers, as demonstrated by your position, obviously, the two frameworks, “magnetic reconnection”, and, Electric Double Layers, are from rival schools of thought.
Rival schools of thought rarely mention a bitterly opposed contrary school that has other ideas.
This issue is not the labels, but the substance, the various physical items, that is being discussed.
As stated from the paper, Basics of Magnetic Reconnection, you linked and I quoted: “Plasma physics is an often controversial field, possibly due to its complexity, and debates over mechanisms for reconnection are far from settled.”
In the double layer paper, Filamentary Structures in U-Shaped Double Layers, previously linked, it was stated in the abstract, “These features include: (i) large-amplitude parallel and perpendicular fluctuating as well as quasi-static electric fields in density cavities, (ii) fairly large-amplitude unipolar parallel electric fields like in a strong double layer (DL)…”
Now, a side-by-side comparison & analysis, of the peer-reviewed papers purporting to describe “magnetic reconnection” with peer-reviewed papers describing Electric Double Layers, is appropriate.
The following quotes are from the peer-reviewed paper: Magnetopause reconnection impact parameters from multiple spacecraft magnetic field measurements published 30 October 2009.
http://www.leif.org/EOS/2009GL040228.pdf
(Dr. Svalgaard, thank you for providing this paper, it’s instructive.)
“Discrepancies between the measured components of E [electric field] and the corresponding components of v B [magnetic field] after a careful error analysis signify a nonideal electric field. We intend to show in a subsequent paper that the Cluster electric field and particle flow data for this event satisfy the criteria for a parallel electric field.”
“With the instantaneous coordinate system and the parallel electric field established, one can place particle moments, such as velocities, pressures, and temperatures, as well as magnetic and electric field measurements…”
“Sufficiently accurate ion and electron moments and electric field measurements within this coordinate system delineate ion and electron diffusion regions.”
These statements from the so-called “magnetic reconnection” paper mesh nicely with the abstract from the double layer paper.
Both papers state “parallel electric fields” are important to the physical process described, respectively in the Electric Double Layer paper and the “magnetic reconnection” paper.
Nice.
The description in the paper puts this “parallel electric field” right at the heart of the process, the “X-line”.
Another double layer paper:
Parallel electric fields in the upward current region of the aurora: Indirect and direct observations, published 2002 Physics of Plasma
http://www.space.irfu.se/exjobb/2003_erik_bergman/articles/PHP03685_ergun.pdf
Authors:R. E. Ergun,a) L. Andersson, D. S. Main, and Y.-J. Su
Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80303
C. W. Carlson, J. P. McFadden, and F. S. Mozer
Space Sciences Laboratory, University of California, Berkeley, California 94720
Abstract (partial): “In this article we present electric field, magnetic field, and charged particle observations from the upward current region of the aurora focusing on the structure of electric fields at the boundary between the auroral cavity and the ionosphere. Over 100 high resolution measurements of the auroral cavity that were taken by the Fast Auroral Snapshot ~FAST! satellite are included in this study. The observations support earlier models of the auroral zone that held that quasi-static parallel electric fields are the primary acceleration mechanism…)
And, here, is another so-called “magnetic reconnection” paper for comparison & analysis to put it in clearer relief. The following is the caption for a schematic of “magnetic reconnection” from the peer-reviewed paper, Recent in-situ observations of magnetic reconnection in near-Earth space, published 11 October 2008:
http://www.leif.org/EOS/2008GL035297.pdf
Figure 1. “(bottom [schematic, page 2 of 7] ) : “Zoom-in on the region around the X-line, with the ion and electron diffusion regions indicated by the shading and the rectangular box, respectively. The quadrupolar Hall magnetic field is pointing in and out of the plane of the figure. The Hall electric field is shown by the red arrows, while the blue arrows mark the oppositely directed jets in the outflow regions. Note that entry and acceleration occur all the way along the current sheet. Figure courtesy of Marit Oieroset.”
To see the schematic in Figure 1. it is on the second page of seven of the PDF, please go to the link above of the paper:
You’ll see that the “Hall electric field is shown by the red arrows” surrounds the X- line at the heart of the “reconnection” structure”.
Electric fields are certainly not periphery. Actually, the “parallel electric fields”, where double layers get their name are right on both sides of the X – region.
Dr. Svalgaard presented this index of a modern text book:
‘Magnetic Reconnection in Plasmas’ by Dieter Biskamp
Max-Planck-Institut für Plasmaphysik, Garching, Germany
Cambridge Monographs on Plasma Physics (No. 3)
Online Publication Date: December 2009
It’s an excellent example of the crisis in astronomy:
This is a 2009 book on “magnetic reconnection” but it doesn’t have an index heading for “electric fields” in contrast to the two “magnetic reconnection” papers I’ve presented (with thanks to Dr. Svalgaard) which do discuss “electric fields” and make clear that “electric fields” are a central component of so-called “magnetic reconnection”.
How complete is a text book on a subject that doesn’t discuss a central physical component of the physical process under discussion?
Although, the text book does have a heading for “Debye Length”, which is a central issue for Electric Double Layers:
Wikipedia entry for Debye length: “In plasma physics, the Debye length (also called Debye radius), named after the Dutch physicist and physical chemist Peter Debye, is the scale over which mobile charge carriers (e.g. electrons) screen out electric fields in plasmas and other conductors. In other words, the Debye length is the distance over which significant charge separation can occur. A Debye sphere is a volume whose radius is the Debye length, in which there is a sphere of influence, and outside of which charges are screened. The notion of Debye length plays an important role in plasma physics, electrolytes and colloids (DLVO theory).
http://en.wikipedia.org/wiki/Debye_length
So, I invite readers to engage in their own side-by-side comparison & analysis of “Electric Double Layer” papers (two) and so-called “magnetic reconnection” papers (the two papers I link in this comment) and it becomes apparent the two processes are actually one and the same process.
Not withstanding Dr. Svalgaard’s protests to the contrary.
Facts are inconvenient things.
James F. Evans says:
August 9, 2010 at 11:18 am
the two frameworks, “magnetic reconnection”, and, Electric Double Layers, are from rival schools of thought.
There are no rival schools of thought. I do not know of ANY practicing plasma physicist who claims the EDL and MR are the same thing.
There is no rivalry, no schools of thought, no two frameworks. No bitter dispute between people who know what they are talking about.
Rival schools of thought rarely mention a bitterly opposed contrary school that has other ideas.
Scientists actually do this all the time. It is part of publishing a scientific paper [and peer-review helps to enforce this] that the paper references opposing views. Now, people with an agenda are the ones that do not mention rivals.
Facts are inconvenient things.
As I have said so many times, magnetic reconnection often results in EDLs, but can also proceed without any electrical effects: just twirl a toy magnetic in free air and you have reconnection going on all the time. Reconnection is about changing magnetic topology. If a conductor is present, electric currents may result. Perhaps you could make a little drawing of a reconnection region and put the EDL on it so it is clear what you are talking about.
The important issue is that magnetic fields and moving neutral plasma are the ingredients in magnetic reconnection. Electric effects follow.
And you still avoid to answer my simple question: what powers the sun? the answer to that may show your agenda and that may be why you avoid the question.
James F. Evans says:
August 9, 2010 at 11:18 am
Your wiki link http://en.wikipedia.org/wiki/Debye_length has this quote:
Hannes Alfven pointed out that: “In a low density plasma, localized space charge regions may build up large potential drops over distances of the order of some tens of the Debye lengths. Such regions have been called electric double layers. An electric double layer is the simplest space charge distribution that gives a potential drop in the layer and a vanishing electric field on each side of the layer.
In the solar wind the Debye length is 10 meters and in the magnetosphere it is 100 m, so fro space plasma the region with the potential drop [the EDL] is of the order of a kilometer or less. Outside of that region there is a no electric field according to Alfven [and everybody else].
And how does “localized space charge regions build up large potential drops”? By that action of the magnetic field in those small regions. This is the fundamental process.
Dr. Svalgaard states: “Reconnection is about changing magnetic topology.”
And, to come to a full understanding of the underlying causes of that “changing magnetic topology” one must investigate the movements of the “electrified particles”, and the electric fields, just as the two “magnetic reconnection” papers I presented show.
But let’s stick to the facts.
What about the fact that the text book’s index you linked doesn’t have a heading for “electric fields” when it is clear that electric fields are central to the “magnetic reconnection” process as described in the two “magnetic reconnection” papers I presented?
What about the fact that “parallel electric field” described in both the double layer papers and the “magnetic reconnection” papers?
What about the “transverse” or ‘perpendicular” electric fields discussed in both sets of papers?
What about the “X” cross section where electric and magnetic fields cross, and, seems to be central to the acceleration of the particles in both sets of papers?
What about the crossed electric and magnetic fields as quantitatively described in the Electric Double Layer process and evidently also important to the “magnetic reconnection” as demonstrated by the two “magnetic reconnection” papers where they discuss the “X” cross section and present it in schematic form?
What about the fact that both sets of papers talk about “pressures” (“magnetic reconnection” paper) and “density cavities” (Electric Double Layer paper)?
What about the paper you presented, Basics of Magnetic Reconnection, that stated magnetic reconnection is “poorly understood”, “controversial”, “far from settled”, and “undergoing revolutionary changes”?
Dr. Svalgaard, we are not discussing “toy magnets” that don’t do anything (is any energy focussed or transferred anywhere by spinning your toy magnet), we are discussing space phenomenon where large amounts of energy are focussed and transferred via “electrified particles”.
I bring facts & evidence via presentation of peer-reviewed published scientific papers…but Dr. Svalgaard wants to focus on whether or not there is any rivalry.
Frankly, it doesn’t matter whether there is a rivalry or not.
Dr. Svalgaard wrote: “Perhaps you could make a little drawing of a reconnection region and put the EDL on it so it is clear what you are talking about.”
Obviously, this is not the forum for “little drawings”, but the so-called “reconnection” region with its “X” cross section is the Electric Double Layer region with crossed electric fields and magnetic fields.
Dr. Svalgaard quoted the Wikipedia entry for Debye Length: “Hannes Alfven pointed out that: ‘In a low density plasma, localized space charge regions may build up large potential drops over distances of the order of some tens of the Debye lengths. Such regions have been called electric double layers. An electric double layer is the simplest space charge distribution that gives a potential drop in the layer and a vanishing electric field on each side of the layer’.”
And, for proper context, the rest of the Hannes Alfven quote: “In the laboratory, double layers have been studied for half a century, but their importance in cosmic plasmas has not been generally recognized.”.
And Dr. Leif Svalgaard is doing his best to keep it that way in spite of the mass of facts & evidence stacked against his position.
Dr. Svalgaard wrote: “In the solar wind the Debye length is 10 meters and in the magnetosphere it is 100 m, so fro space plasma the region with the potential drop [the EDL] is of the order of a kilometer or less. Outside of that region there is a no electric field according to Alfven [and everybody else].”
But there is an electric field in that region and it is central to both Electric Double Layers and so-called “magnetic reconnection”…wonder why?
Dr. Svalgaard wrote: “In the solar wind the Debye length is 10 meters…”
That would necessarily mean that there is an Electric Double Layer in the solar wind, which means there are electric fields in the solar wind and that electric currents are generated in the solar wind.
Dr. Svalgaard wrote: “…in the magnetosphere it [Debye Length] is 100 m…”
That would necessarily mean that there are Electric Double Layers in the magnetosphere, which means there are electric fields in the magnetosphere and that electric currents are generated in the magnetosphere.
This I have already stated: Colliding flows of plasma (and their attendant magnetic fields) will give rise to electric currents.
Dr. Svalgaard wrote: “And how does ‘localized space charge regions build up large potential drops’? By that action of the magnetic field in those small regions. This is the fundamental process.”
It is the combination of magnetic fields and the “electrified particles” and their self-organization ability as Irving Langmuir described in the 1920’s and 1930’s. Remember, anyplace a plasma is present by definition there will be Coloumb attraction between the free electrons & ions (“electric” attraction). Now, that doesn’t have to be an organized field, per se, but that is why NASA sometimes refers to “electrified gas”. In that sense, plasma is “electrified”.
So, in space, anyplace there is plasma, there will be “electrical attraction”.
Upon collision of two bodies of flowing plasma (and the attendant magnetic fields) electric currents are generated and energy is transferred via those electric currents.
Electric Double Layers are important in plasma dynamics and is an important dynamic where bodies of space plasma come into contact.
It is the obfiscation of the concept & term, “magnetic reconnection”, which prevents astronomy from fully appreciating the central role the Fundamental Force of Electromagnetism has in space dynamics.
James F. Evans says:
August 9, 2010 at 2:10 pm
So, in space, anyplace there is plasma, there will be “electrical attraction”.
Not at all, as there is an equal amount of charges moving at high thermal speeds.
Mozer has a good description of the process:
“Magnetic field reconnection is defined as the process that occurs when magnetized plasmas with different magnetic field orientations flow together to alter the connectivity of the magnetic field.”
http://solarmuri.ssl.berkeley.edu/~welsch/brian/FSL/2006/mozer_reconn_v4.pdf
Note there is no mention of Electric Double Layers, as there aren’t any.
The situation Mozer describes is what happens when the solar wind meets the magnetosphere. In the solar wind there is no electric field, but in the frame of the Earth there is an electric field E = V x B [V=solar wind speed, B=magnetic field]. The changing magnetic field generates the necessary currents. What you get wrong is the direction of causality: The magnetic field and the kinetic energy of the moving plasma is what generates all the electric fields and accelerations.
And again: what powers to Sun? To get some credibility, you should not continue to evade this question.
Dr. Svalgaard:
I want to thank you for the Mozer paper. The paper is very enlightening.
Some quotes from the paper:
“The physics of reconnection depends on the electric field component out of the plane of Fig. 1 at the center of the figure, which is sometimes called the tangential electric field.”
“If it is zero [the Electric field], the two plasmas flow around each other into or out of the plane of the figure because there is no ExB/B2 flow in the plane of the figure in this central region.”
So, no electric field — then, there is no “reconnection”.
Continuing from the Mozer paper:
“On the other hand, if the tangential electric field is non-zero, the plasmas continue flowing towards each other into the central region of the figure and magnetic field reconnection occurs as discussed below.”
The Mozer paper asks the question: “Why has there been so much theoretical interest in making Eo large?”
And, then, the Mozer paper answers the question:
“Consider the current out of the plane in the central region of Fig.1, which is required by the curl of the magnetic field. A non-zero electric field results in a positive value of j·E in the central region of the figure and conversion of electromagnetic energy into particle energy, which is what magnetic field reconnection is all about.”
Please focus on and highlight: “conversion of electromagnetic energy into particle energy [kinetic energy], which is what magnetic field reconnection is all about.”
Seems the author of the paper, F. S. Mozer, considers electromagnetic energy central to this process, whether the process is called Electric Double Layers or “magnetic reconnection”.
The Mozer paper asks the question: “Where does the energy associated with this positive j·E originate?”
“To answer this question, an analogy will be made with the electric circuit of Fig. 2, consisting of a battery and a resistor. From freshman physics, the electromagnetic energy conversion rate is VI where V is the battery voltage and I is the current.”
Ah, an “electric circuit”, much as Hannes Alfven theorized and demonstrated empirically in the laboratory.
“If the EMF [electromotiveforce] (in the case of Fig.2, a battery) is constant, the energy conversion rate is constant.”
“This is just one example of problems arising from misinterpretation of the concept of moving magnetic field lines.”
One of the prior commenters spoke to this “misinterpretation of the concept of moving magnetic field lines.”
The Mozer paper asks the question: “Where does the converted electromagnetic energy go?”
And, then, answers: “It accelerates the plasma in the central region of Fig. 1 just as the resistor in Fig. 2 warms up due to energy conversion from the battery.”
More language consistent with an “electric circuit” model just as Hannes Alfven advocated.
“The flux, not the energy, of the ions emerging from the diffusion region increases with the increasing magnitude of the reconnection electric field, Eo.”
The Mozer paper asks the question: “What happens to the plasma that is accelerated by the electromagnetic energy conversion?”
The author, Mozer, makes explicit reference to Maxwell’s equations:
“…the magnitude of the magnetic field evolves as is required by Maxwell’s equations if magnetic field lines move with the ExB/B2 velocity.”
And everybody knows that Maxwell’s equations describe a reciprical relationship between magnetic fields & electric fields. In other words, you can’t have magnetic fields without the presence of the Coloumb attraction, the attraction between opposite charges due to Coulomb force, in a plasma where there is the presence of free electrons & ions.
Further from the Mozer paper: “This violation of Maxwell’s equations means that there must be a parallel electric field in the central region such that the magnetic field evolution in this region cannot be obtained by any means other than solving Maxwell’s equations.”
There’s that pesky “parallel electric field”, right at the heart of the so-called “magnetic reconnection”, just as I have repeatedly asserted.
Further from the Mozer paper:
“The discussion thus far has left many unanswered questions. For example:
• How do the ions and electrons move to create the current, j?
• How are the ions accelerated to the Alfven speed?
• How is the parallel electric field in the central region generated?
These questions will all be discussed through application of the Generalized Ohm’s Law as derived from the two-fluid equations of motion for a unit volume of plasma, which are (Spitzer, 1956):”
The framework used to understand so-called “magnetic reconnection” is an electromagnetic framework.
Further from the Mozer paper:
“This requires an electric field, En, perpendicular to the magnetic field and pointing towards the center of Fig. 8 from both sides in the ion diffusion region.
Figure 8”
Ah, mention of “perpendicular electric field”.
This is a critical paragraph from the Mozer paper:
“The electric field, En, existing along the dashed X in Fig. 8 over a scale size of c/ωpi, has a non-zero divergence so it must result from charge separation. This requires that electrons move along the magnetic field lines into the dashed box to create the charge separation. The parallel (to B) electric field in the dashed box accelerates these electrons to the outgoing ion bulk velocity, after which they are ejected into the upper and lower central regions. Thus, the average parallel electric field in the dashed box must be downward (upward) in the upper (lower) part of the dashed box.”
“Parallel electric field” same as in an Electric Double Layer.
“Charge seperation” same as in an Electric Double Layer.
The side-by-side comparison & analysis between this “magnetic reconnection” paper and the full length Electric Double Layer paper, previously linked, strongly suggests the authors of the respective papers are discussing the same physical event.
The Mozer paper asks the question: “What is the nature of the parallel electric field inside the dashed box of Fig. 8?”
And, then, answers:
“The right side of equation 11 must differ from zero in this region because of the parallel electric field on the left side. Thus, the parallel electric field must be associated with the time derivative of j (inertial effects), the divergence of the pressure tensor, or finite resistivity. Experimental data suggests that it is associated with the pressure tensor (Mozer et al, 2002; Mozer, 2005), but this is an important issue that remains to be fully resolved.”
This paper supports my assertions about the relationship or reality that so-called “magnetic reconnection” is the same “event” as an Electric Double Layer.
True, the author doesn’t use “Electric Double Layer”…he doesn’t have to, all the constituent processes he outlines are consistent with physical processes associated with Electric Double Layers.
James F. Evans says:
August 9, 2010 at 5:52 pm
again: what powers the Sun? That you continue to evade this question shows your reluctance to expose your agenda.
I want to thank you for the Mozer paper. The paper is very enlightening.
If was supposed to, but, alas, you completely misunderstand almost every sentence. I was hoping you would react extensively so that your misunderstanding would become evident, and you nicely obliged.
True, the author doesn’t use “Electric Double Layer”…he doesn’t have to, all the constituent processes he outlines are consistent with physical processes associated with Electric Double Layers.
Except that you have cause and effect reversed. Mozer does not.
About ‘no electric field – no reconnection’: the E = V x B electric field in the frame of the magnetosphere is generated by the neutral plasma streaming into a [stationary] magnetic field, so the electric field owes its existence to the magnetic field, here and everywhere else in the cosmos. Charge separation is due to the magnetic field [deflecting opposite charges in opposite directions].
again: what powers the Sun? That you continue to evade this question shows your reluctance to expose your agenda.
James F. Evans says:
August 9, 2010 at 5:52 pm
again: what powers the Sun? That you continue to evade this question shows your reluctance to expose your agenda.
I want to thank you for the Mozer paper. The paper is very enlightening.
If was supposed to, but, alas, you completely misunderstand almost every sentence. I was hoping you would react extensively so that your misunderstanding would become evident, and you nicely obliged.
Here is something on laboratory evidence of reconnection:
http://www.pppl.gov/pub_report/1997/PPPL-3236.pdf
The thnig you have to learn is that everything interesting is due to electric currents and that electric currents are due to dynamo processes where a neutral plasma is driven across a magnetic field. If two plasmas with opposite magnetic fields are driven together, magnetic reconnection greatly enhances their interaction.
again: what powers the Sun? That you continue to evade this question shows your reluctance to expose your agenda.
Dr. Svalgaard:
The Mozer paper speaks for itself, and, no, I haven’t misunderstood the paper.
It is you, who can’t accept that the presented scientific papers contradict your world-view.
From the Mozer paper:
“The physics of reconnection depends on the electric field component out of the plane of Fig. 1 at the center of the figure, which is sometimes called the tangential electric field.”
“If it is zero [the Electric field], the two plasmas flow around each other into or out of the plane of the figure because there is no ExB/B2 flow in the plane of the figure in this central region.”
It’s straightforward, “The physics of reconnection depends on the electric field component…”
No electric field, no “reconnection”. In other words, the presence of the “tangential electric field” is a necessary prerequisite.
The author, F. S. Mozer, even provides an example of where there is no “tangential electric field” and, thus, no “reconnection”. I don’t know how the author could make it any clearer or more explicit.
Dr. Svalgaard wrote: “I was hoping you would react extensively so that your misunderstanding would become evident, and you nicely obliged.”
Actually, primarily, I let the paper speak for itself by simply quoting the Mozer paper with minimal additional comments.
I submit the only thing evident is Dr. Svalgaard’s unwillingness to acknowledge the obvious, hoping that some readers would accept his pronouncements.
The problem is that the scientific papers presented don’t support Dr. Svalgaard’s prouncements.
No, I don’t have cause & effect reversed and nether do the scientists that authored the Electric Double Layer papers.
You see, Dr. Svalgaard, your problem is not with me, it’s with any Science that contradicts your world-view. You have demonstrated this many times.
Dr. Svalgaard wrote: “…the E = V x B electric field in the frame of the magnetosphere is generated by the neutral plasma streaming into a [stationary] magnetic field, so the electric field owes its existence to the magnetic field…”
Can you point to where the Mozer paper agrees with the above comment.
Evans wrote: “…you can’t have magnetic fields without the presence of the Coloumb attraction, the attraction between opposite charges due to Coulomb force, in a plasma where there is the presence of free electrons & ions.”
If there is plasma, then there is Coulomb attraction between opposite charges, this Coulomb attraction can be called “electric force”.
The definition of plasma: Free electrons & ions.
You see, Dr. Svalgaard, an equally valid world-view is that everything started as plasma, with free electrons & ions, as Hannes Alfven postulated, “in the beginning was the plasma”.
And, with plasma there must be “electric force” or Coulomb attraction between the free electrons & ions (opposite charges), or there wouldn’t be plasma — it would be neutral matter with no magnetic or electric fields.
Dr. Svalgaard’s assertion, “charge seperation is due to the magnetic field” is an assumption. It’s equally valid to assert that magnetic fields are due to charge seperation. Maxwell’s equations assert that magnetic & electric fields are reciprical — there is no hiarchy to be derived from Maxwell’s equations.
But Science does know that a stationary body of plasma will not have an organized magnetic field.
But, obviously, Dr. Svalgaard will not accept my assertions, even if I said the sky is blue, Dr. Svalgaard would disagree.
So better to let the scientific papers do the talking:
The full, complete, and unabridged double layer paper:
Parallel electric fields in the upward current region of the aurora: Indirect and direct observations, published 2002 Physics of Plasma
http://www.space.irfu.se/exjobb/2003_erik_bergman/articles/PHP03685_ergun.pdf
Authors:R. E. Ergun,a) L. Andersson, D. S. Main, and Y.-J. Su
Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80303
C. W. Carlson, J. P. McFadden, and F. S. Mozer
Space Sciences Laboratory, University of California, Berkeley, California 94720
Abstract (partial): “In this article we present electric field, magnetic field, and charged particle observations from the upward current region of the aurora focusing on the structure of electric fields at the boundary between the auroral cavity and the ionosphere. Over 100 high resolution measurements of the auroral cavity that were taken by the Fast Auroral Snapshot ~FAST! satellite are included in this study. The observations support earlier models of the auroral zone that held that quasi-static parallel electric fields are the primary acceleration mechanism…These observations suggest that the parallel electric fields at the boundary between the auroral cavity and the ionosphere are self-consistently supported as oblique double layers.”
The full, complete, and unabridged F. S. Mozer “magnetic reconnection” paper:
http://solarmuri.ssl.berkeley.edu/~welsch/brian/FSL/2006/mozer_reconn_v4.pdf
It needs to be noted and it supports my position: F. S. Mozer is also one of the authors of the Electric Double Layer paper linked to above.
Readers, review the two papers and decide for yourself.
James F. Evans says:
August 9, 2010 at 9:34 pm
Dr. Svalgaard wrote: “…the E = V x B electric field in the frame of the magnetosphere is generated by the neutral plasma streaming into a [stationary] magnetic field, so the electric field owes its existence to the magnetic field…”
Can you point to where the Mozer paper agrees with the above comment.
Right off the bat in Figure 1, where the E = – V x B electric field is shown. Mozer does not need to specify the formula because every plasma physicist knows it by heart.
Read the ‘Discussion’ part of http://www.leif.org/EOS/2001GL013014.pdf to learn what drives what.
You seem to ignore that I have told you again and again that electric fields are of utmost importance and that they are generated by neutral plasma moving with respect to magnetic fields. Electric Double Layers can form when conditions are right, but have nothing to do with magnetic reconnection.
Again: it is telling that you duck the question: what powers the Sun?
This post is about Saturn’s aurora.
Electric Double Layers have been identified in Earth’s aurora. It’s reasonable to postulate that Saturn’s aurora has similarities to Earth’s aurora (as well as differences).
So-called “magnetic reconnection” has been claimed as also being associated with Earth’s aurora, but I have demonstrated by presenting both Electric Double Layer papers and “magnetic reconnection” papers that the physical processes occuring during the events are the same, and, just as important, are consistent with a full spectrum ELECTROMAGNETIC framework.
Concepts & terms that fail to address electric fields, magnetic fields, motions of “electrified particles”, electric currents, and the free electrons & ions physical configurations are inadequate analytical tools.
Failure to consider or observe & measure all aspects of the electromagnetic dynamic, including the electric field, the magnetic field, the motions and configurations of charged particles is negligent scientific conduct and won’t provide useful scientific data.
What passes today as so-called “magnetic reconnection” is actually the Electric Double Layer physical process, an electromagnetic process.
Thus, the key to understanding Saturn’s aurora is applying an electromagnetic framework, more specifically, the Electric Double Layer physical structure & process that has been studied in the laboratory for 50 years.
The Fundamental Force of Electromagnetism is known to be scale independent and fractal.
It is now apparent that when flowing currents of plasma, charged particles, collide with each other, in space, an Electric Double Layer is formed and electric currents are caused.
In study of solar system dynamics, it is essential to consider all electromagnetic dynamics and the processes that are known to be associated with an electromagnetic framework.
The Electric Double Layer is one of those processes:
What has been claimed as so-called “magnetic reconnection” is actually an Electric Double Layer.
The term & concept “magnetic reconnection” is an antiquated, pre-space age (1946), incomplete analytical tool, which did not consider electric fields or electric currents or the motions and configurations of charged particles. This failed analytical tool has been superceded by the full spectrum electromagnetic concept (if not yet term), Electric Double Layer.
Scientific papers presented:
Filamentary Structures in U-Shaped Double Layers, 2005
http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2005AGUFMSM41C1202D&db_key=AST&data_type=HTML&format=&high=42ca922c9c05019
Parallel electric fields in the upward current region of the aurora: Indirect and direct observations, published 2002 Physics of Plasma
http://www.space.irfu.se/exjobb/2003_erik_bergman/articles/PHP03685_ergun.pdf
Magnetopause reconnection impact parameters from multiple spacecraft magnetic field measurements published 30 October 2009
http://www.leif.org/EOS/2009GL040228.pdf
Recent in-situ observations of magnetic reconnection in near-Earth space, published 11 October 2008
http://www.leif.org/EOS/2008GL035297.pdf
Collisionless Magnetic Field Reconnection From First Principles: What It Can and Cannot Do
http://solarmuri.ssl.berkeley.edu/~welsch/brian/FSL/2006/mozer_reconn_v4.pdf
Readers review & decide.
James F. Evans says:
August 10, 2010 at 9:50 am
This post is about Saturn’s aurora.
Electric Double Layers have been identified in Earth’s aurora.
What has been claimed as so-called “magnetic reconnection” is actually an Electric Double Layer.
Electric Double Layers often form in aurorae [near the Earth and Saturn], but the magnetic reconnection that helps create the conditions for their formation happen way out in the magnetotail, hundreds of times further out than the aurorae, so is clearly not the same thing, no matter how many times you misunderstand a paper I provide you with a link to.
Again: what powers the Sun? This you dare not say for fear of exposing your agenda.
http://en.wikipedia.org/wiki/Double_layer_(plasma)
Double layer (plasma):
“A double layer is a structure in a plasma and consists of two parallel layers with opposite electrical charge. The sheets of charge cause a strong electric field and a correspondingly sharp change in voltage (electrical potential) across the double layer. Ions and electrons which enter the double layer are accelerated, decelerated, or reflected by the electric field. In general, double layers (which may be curved rather than flat) separate regions of plasma with quite different characteristics. Double layers are found in a wide variety of plasmas, from discharge tubes to space plasmas to the Birkeland currents supplying the Earth’s aurora, and are especially common in current-carrying plasmas. Compared to the sizes of the plasmas which contain them, double layers are very thin (typically ten Debye lengths), with widths ranging from a few millimeters for laboratory plasmas to thousands of kilometres for astrophysical plasmas.”
The following is the caption for the image of Saturn’s aurora presented on the right-hand side of the Wikipedia webpage for the Double layer (plasma) entry:
“Saturnian aurora whose reddish colour is characteristic of ionized hydrogen plasma.[1] Powered by the Saturnian equivalent of (filamentary) Birkeland currents, streams of charged particles from the interplanetary medium interact with the planet’s magnetic field and funnel down to the poles.[2] Double layers are associated with (filamentary) currents,[3][4] and their electric fields accelerate ions and electrons.[5]”
** numerals stand for footnotes of authorities in the Wikipedia entry, Double layer (plasma).
Readers are invited to review the Wikipedia entry for Double Layers and compare & constrast the Wikipedia entry with the presented scientific papers for both Electric Double Layers and so-called “magnetic reconnection”.
James F. Evans says:
August 10, 2010 at 5:31 pm
“A double layer is a structure in a plasma and consists of two parallel layers with opposite electrical charge…
Absolutely, but that has nothing to do with reconnection that occurs when you have two parallel magnetic fields being pressed together by neutral plasmas.
Again: what powers the sun? This should be easy for you to demonstrate with your superior knowledge of the Electric Universe. I urge readers to ponder your reluctance to respond.
Leif Svalgaard says:
Your comment is awaiting moderation.
August 10, 2010 at 6:12 pm
James F. Evans says:
August 10, 2010 at 5:31 pm
“A double layer is a structure in a plasma and consists of two parallel layers with opposite electrical charge…”
Absolutely, but that has nothing to do with reconnection that occurs when you have two parallel magnetic fields with opposite polarities being pressed together by neutral plasmas.
The peer-reviewed, published scientific papers say otherwise.
“Neutral plasma” = Free electrons & ions subject to Coulomb attraction.
Plasma:
Free negative electron — Coulomb attraction — Positive ion
Free negative electron — electric attraction — positive ion
Plasma by its very nature is dynamic.
The EMF (electromotiveforce) is billions of times stronger than gravity.
Coulomb’s law is a law of physics describing the electrostatic interaction between electrically charged particles. It was studied and first published in 1783 by French physicist Charles Augustin de Coulomb and was essential to the development of the theory of electromagnetism. Nevertheless, the dependence of the electric force with distance (inverse square law) had been proposed previously by Joseph Priestley and the dependence with both distance and charge had been discovered, but not published, by Henry Cavendish, prior to Coulomb’s works.
http://en.wikipedia.org/wiki/Coulomb's_law
The “electric force” between free electrons & ions is present in plasma.
James F. Evans says:
August 10, 2010 at 9:41 pm
The “electric force” between free electrons & ions is present in plasma.
No, in your own link to Debye Length: http://en.wikipedia.org/wiki/Debye_length
It states [correctly] “In plasma physics, the Debye length (also called Debye radius), named after the Dutch physicist and physical chemist Peter Debye, is the scale over which mobile charge carriers (e.g. electrons) screen out electric fields in plasmas and other conductors.” This means that charges do not feel any electric force outside of the Debye radius. In the solar wind and interstellar space the Debye radius is only 10 meter.
Again: what powers the Sun? This you dare not say for fear of exposing your agenda.
“At the International Space Station, roughly 350 kilometres away from the surface of the Earth, there are around 10 trillion particles per cubic meter. 100,000 kilometres from the Earth (over a third of the way to the Moon, where there is absolutely no influence from the Earth’s atmosphere), there are around seven million particles per cubic metre. At the edge of the Solar System, the density is down to about a thousand atoms per cubic metre.”
It would seem the density per cubic meter of charged particles, plasma, is enough for free electrons & ions to exert Coulomb force on each other.
So, no, your response is false.
James F. Evans says:
August 10, 2010 at 10:57 pm
It would seem the density per cubic meter of charged particles, plasma, is enough for free electrons & ions to exert Coulomb force on each other.
But since there are equal number of both charges they all cancel out.