From Spaceweather.com with apologies to Linus and Charles Schulz
The Solar and Heliospheric Observatory (SOHO) is tracking an enormous magnetic filament on the sun. It stretches more than one million kilometers from end to end, which makes it an easy target for backyard solar telescopes. For the seventh day in a row, an enormous magnetic filament is hanging suspended above the surface of the sun’s southern hemisphere. The Solar and Heliospheric Observatory (SOHO) has a great view. How long can it last? Solar filaments are unpredictable. If this one collapses and hits the stellar surface, the impact could produce a powerful Hyder flare.
The most recent SOHO image is here
Hyder Flares: from Australian IPS 1. What is a Hyder flare?
Flares are intense brightenings that occur in the solar chromosphere. Flares are generally observed from Earth using narrow band filters, typically with a bandwidth of less than 0.1 nm, and often centred on the Hydrogen-Alpha wavelength of 656.3 nm. (Flares also have counterparts, that is, sudden outbursts, in the radio and X-ray spectrum).
Most flares occur around active regions associated with sunspot groups. However, occasionally a flare (sudden brightening) is observed well away from an active region or sunspot group. These flares are invariably associated with the sudden disappearance of a large (thick, long, ‘bushy’) dark solar filament, and are termed Hyder flares.
2. Why are Hyder flares so named?
Max Waldmeier wrote a paper in 1938 which described the phenomenon of suddenly disappearing filaments (disparition brusque), and mentioned that these can be associated with flare-like brightenings, but it was left to Charles Hyder to postulate the first comprehensive mechanism for the such flares.
Following on work from his doctoral thesis with the University of Colorado in Boulder (1964), Hyder published two papers in the second volume of the journal Solar Physics (1967) in which the mechanism by which Hyder flares might occur was discussed in detail. Hyder was then on the staff of the (US) Air Force Cambridge Research Laboratories at the Sacramento Peak Observatory in New Mexico.
It was these papers in Solar Physics by which Hyder’s name became associated with the flares in question, even though he was by no means the first to observe them.
3. What are the characteristics of Hyder flares?
As previously mentioned, the name Hyder flare is given to a flare that occurs away from an active region or sunspot group and that is associated with the sudden disappearance of a dark filament. The appearance of these flares can range from a string of bright knots on one or both sides of the filament (or rather, the position previously occupied by the filament, sometimes called the filament channel), to a single or double ribbon flare. The ribbons are parallel to the filament channel. If only one ribbon is present, it will lie to one side of the channel, whereas if two parallel ribbons occur, one ribbon will lie on one side of the filament channel, and the other ribbon will lie on the opposite side.
One interesting characteristic of Hyder flares is that they usually develop or rise to maximum brightness much more slowly than do the more common flares associated with active regions. The larger Hyder flares may take 30 to 60 minutes to rise to a peak intensity, and then they may last for several hours. Although they may attain a large area, they usually have a relatively low intensity. Thus, classifications for a large Hyder flare may read 2F, 2N or possibly even 3F. This contrasts to an active region flare in which 3F is very rare. An active region flare that attains sufficient area to put it into the importance class 3, will invariably have either a Normal or more usually a Brilliant brightness classification.
X-ray flares and radio (microwave) bursts associated with the optical Hyder flare, are also generally long lived phenomenon and are classified as the gradual rise and fall type of event (in contrast to the impulsive and complex events associated with large active region flares).
Generally Hyder flares are not associated with energetic particle emission or geomagnetic storms (implying that they may not be associated with a coronal mass ejection). However, this is not always the case, as a large halo CME observed by the LASCO solar coronagraph on board the SOHO spacecraft was most definitely associated with a Hyder flare (2N/M1) observed on 12 September 2000. This same complex also appeared to have produced energetic protons at geosynchronous orbit with energies in excess of 100 MeV, and in substantial numbers at energies of 10 MeV. It is believed that the sudden storm commencement observed at 0450UT 15 September, and the subsequent minor geomagnetic storm was produced by this particular CME.
4. What produces Hyder flares?
Hyder’s explanation of the flare type now named after him depended on the observational evidence that (1) often the flare was a parallel ribbon flare with one ribbon each side of the filament channel, and (2) that geomagnetic storms were not associated with these flares. This led to the speculation that the filamentary material was not ejected far into the corona, but in fact fell back to the chromosphere producing the flare.
Stable or quiescent filaments are believed to lie in and along a magnetic trough. It is thought that the sudden disappearance of such a filament is due to a reconfiguration of the field. In essence, the magnetic trough becomes a magnetic ridge (the bottom of the trough elevating in a period of tens of minutes to become the peak of the ridge). In this process, the filamentary material (cooler gas) is thought to be accelerated into the corona. Hyder’s explanation is that, in the case of the Hyder flare, some or even most of the filament material, instead of suffering acceleration and ejection, falls down the sides of the magnetic ridge and interacts with the lower chromospheric material producing the flare. If the infall process is symmetrical, then the double parallel ribbon flare will result, if asymmetrical, then only one ribbon results. If the infall is sporadic, or the material insufficient, then only bright knots of flare are produced. Hyder did calculations to show that the kinetic energy of the infalling material should be sufficient to provide the required flare energy release observed.
Of late, the Hyder mechanism has come into question. Some people (notably Zirin) have questioned whether infall occurs, stating that the magnetic reconfiguration must always produce ejection. The respective roles of flares and CME’s in solar active processes has also been hotly debated, and this has implications for the exact mechanism of Hyder flares. We certainly have enough observational evidence to show that Hyder flares can be associated with both CME’s and energetic particle production. For the moment, the question of Hyder flare production mechanism appears unresolved, and will probably be sidelined until the more significant (and undoubtedly related) issue of CME – flare production mechanism is sorted out.
The bottom line is that at this stage in solar physics we do not really know what produces a flare nor what produces a CME. There are competing theories, but all tend to have deficiencies with respect to matching the observational evidence. We certainly believe that they all depend on the reconfiguration of magnetic fields as their primary energy source, but in the final analysis, we really only believe this because we can conceive of no other solar energy source of sufficient magnitude.
Plenty of sidetracking along the way.
But, looks good so far Leif.
~
Leif Svalgaard (07:28:12) :
OK, we then start. First we need to establish some facts based on observations. Filaments [and prominences = filaments seen at the edge of the Sun] can last for weeks. They are cool clouds suspended in the hot corona by magnetic fields. The clouds condense out of the corona and although the matter seems to ‘hang’ there for weeks, it is really a very dynamical phenomenon: the material is continually falling down onto the surface, but being replaced by new material condensing out of the corona. This is seen clearly in this video: http://www.youtube.com/watch?v=mZkJcAB2aSQ
1: they are cool because we can see them in lines of Hydrogen
2: they are suspended temporarily by magnetic fields as can be seen from the gracefully curved field lines lit up by the material.
3: gravity is pulling the material down [as it always does no matter where].
Leif Svalgaard (08:32:10) :
Leif Svalgaard (07:28:12) :
Since there were no objections or questions [feel free at all times to return to points you want clarified or objects to – I’ll number all conclusions], I’ll press on.
4. From these observations [and from theory – Alfven’s discovery] it is clear that the plasma at least at times is trapped or tied to the field lines – as it doesn’t fall down right away.
5. Since gravity pulls the plasma down, there is a downwards force which is balanced by the magnetic force holding the plasma up [at least temporarily]. The net result is a deformation of the magnetic field as seen in one of the Figures at the top of the page: http://www.ips.gov.au/Images/Educational/The%20Sun%20and%20Solar%20Activity/Solar%20Flares/hyderflr.gif
Leif Svalgaard (09:15:25) :
Leif Svalgaard (08:32:10) :
6. The total mass in a [or just a few] large filament is comparable to that in the rest of the corona.
7. The ‘coronal rain’ [seen in the video] drains the filament at a rate sufficient to deplete the whole corona within a few hours.
8. Those two observational results imply that there is continual circulation of plasma that readily condense [because space is basically cold] into the prominences. And that the equilibrium that allows the filament to exist as a structure [even though its material is continually recycled] is a dynamic one played out as the interaction of magnetism and gravity.
~
Some nice personal touches there Leif.
You’re ok with most of this, aren’t you Evans? (I hope so, or I will need a glass of wine and a smoke geesh)
Just so people know, yes I have trashed some comments attacking Dr. Svalgaard.
Dr Svalgaard thank you for your efforts and generosity. I hope I did not detract from the information you are sharing, I just think the picture here is much wider and massive, than anything we ever thought possible, or believable.
Our resources as human beings, are really, well and truly limited.
Thank you. I think you know that. And I would ask anyone here to refrain from any meanspiritedness please.
Peace.
Thanks.
This is the wrong thread for this, but you all may appreciate, the most recent interview of Lord Monckton:
http://www.kingworldnews.com/kingworldnews/Broadcast/Entries/2010/2/27_Lord_Christopher_Monckton.html
….which includes a few interviews he did during his month in Australia.
James F. Evans (12:07:27) :
Please provide a paper that discusses observations & measurements which relate and shed light on the ionization level of the photosphere of the Sun.
Perhaps this will help:
http://www.cup.es/resources/0521846560/7706_Saha%20equation.pdf [Figure 3]
Also shows that the early universe was not a plasma at all.
The Saha equation [like Maxwell’s equations] is but a shorthand for untold observations and measurements.
The ionization state directly determine the depth of spectral lines and can thus be directly observed.
James F. Evans (13:16:21) :
But a filament is not neutral matter, it is plasma, charged particles, which respond to electromagnetic forces.
Plasma is neutral, just like a block of copper which consists of charged particles: positive copper nuclei and negative electrons.
Leif Svalgaard (09:23:09) :
tallbloke (08:54:01) :
How would we know if we were less or more than halfway to understanding the universe?
Granted that some people do not understand even the tiniest bit of the universe, the appropriate answer is that ‘it is turtles all the way down’.
At some point, the turtles rest on assumptions about which way is down, and how far “all the way” is.
The Onel & Mann paper [being the newest] says: “Due to the photospheric plasma motion [with velocity u across the magnetic field B] the Lorentz force q u x B acts on the charges q of the plasma and leads to generation of an electric current”.
Dr. Svalgaard (11:52:37) :”This is the mechanism that I have been trying to make you understand for months now [‘ad nauseam’]. I really wish you were not so education-resistant.”
the Carlqvist & Alfven paper
says [page 204]: “If photospheric motion in the presence of magnetic fields produces voltage differences […] a current starts to flow”.
Dr. Svalgaard (12:18:00) : “again, this is the mechanism that I have been trying to make you understand for months now.”
Actually, Dr. Svalgaard, neither paper says what causes this motion. You assume it does, but that’s not what the papers say.
Read the quotes you provided from the papers, no mention of “gravity” or “temperature”.
Now, it’s true both are present at the surface of the Sun, the photosphere, but temperature (random atomic motion) with any corresponding increase in temperature (increase in random atomic motion) tends to dissipate magnetic fields because magnetic fields are caused by organized charged particle motion.
Temperature is unorganized, random atomic motion. That’s why a iron magnet will lose it’s magnetic field when heated.
These observations tends to discount Dr. Svalgaard’s hypothesis.
Gravity is an attraction toward a central point, not a side to side motion. But gravity is a fundamental force and present in all bodies with mass.
So, these two factors don’t spring out as reasons for the initial motion, but I do state a caveat:
I have already raised the idea of plasma without motion as a isolated hypothetical and as a hypothetical condition in the Sun in prior posts.
Evans (11:39:02) 2/24/10: “… because plasma does not want to stand still (the law of entropy) a kind of Biermann battery mechanism is effected, yes, a type of internal dynamo where the plasma wants to unwind, this causes the motion of plama and resulting magnetic fields and possibly the rotation of the Sun. These flows of plasma and their self-sustaining magnetic fields collide with other magnetic fields and charge-seperated electric currents result.”
Yes, the Biermann battery mechanism, a type of internal dynamo.
So, this is nothing new to me as you incorrectly imply with your comment.
Seems like another one of Dr. Svalgaard’s strawman arguments, he puts up from time to time in order to make himself look good.
So, no it is not an idea that you have been communicating for “months, now” that I have been resistant to.
Dr. Svalgaard, I appreciate the paper you provided which states in part:
“Ionization in the sun and universe In the photosphere of the sun, the mass density is ~3 10–4 kg/m3 which corresponds to 2 1023 protons/m3 (mp = 1.67 10–27 kg). Since this is substantially larger than the 50% density (42) for T = 6400 K, the plasma must be more than 50% neutral. Indeed, one can impose the criterion nr+1 + nr = 2 1023m–3 onto (40) to find that nr+1/nr = 4 10–4 at 6400 K; it is mostly neutral.”
This is a theoretical exercise and one worth exploring.
But the paper goes on to state its own caveat:
“In the dilute gases often found in astrophysics, the temperature required for ionization is quite low. Once an atom is ionized, it has few opportunities to become neutral again; an interaction with a free electron is required and these are rare in a dilute gas”.
This passage would seem to contradict the first passage and open the door to a higher level of ionization at the surface of the Sun, the photosphere.
And, another caveat: Discussions about the “beginning of the Universe” are meaningless — Man is not privileged to know how the Universe started, not withstanding a lot of guess work surrounding the so-called “big bang” hypothesis.
But all this is a diversion because that’s not where I started — this is where I started:
“The moving plasma, i.e., charged particles flows, are currents that produce self-magnetic fields, however weak.” — Dr. Anthony L. Peratt, Los Alamos National Laboratory
“An electromotive force [mathematical equation] giving rise to electrical currents in conducting media is produced wherever a relative perpendicular motion of plasma and magnetic fields exists.” — Dr. Anthony L. Peratt, Los Alamos National Laboratory
And, that is where the Carlqvist & Alfven paper started and where the One & Mann paper started. And, when pressed, you acknowledge.
So, Dr. Svalgaard, why do you obfiscate with words like “rain” and “cloud”? And, why do you carry on without mention of electromagnetic forces?
Evans (13:16:21) : “But a filament is not neutral matter, it is plasma, charged particles, which respond to electromagnetic forces.”
Dr. Svalgaard (14:13:13) responded: “Plasma is neutral…”
Plasma can be quasi-neutral, with equal numbers of free electrons & ions in random distribution.
But, when plasma flows, you get:
“The moving plasma, i.e., charged particles flows, are currents that produce self-magnetic fields, however weak.” — Dr. Anthony L. Peratt, Los Alamos National Laboratory
“An electromotive force [mathematical equation] giving rise to electrical currents in conducting media is produced wherever a relative perpendicular motion of plasma and magnetic fields exists.” — Dr. Anthony L. Peratt, Los Alamos National Laboratory
Plasma can and often does take the form of charged-seperated, charged particles, in other words, electric current.
Again, Dr. Svalgaard, the two papers make quite clear the filaments are plasma animated by electric currents.
Why are you so resistant to this proposition?
I’ve been trying to teach you this for months…but you refuse to learn…
Why?
”””charles the moderator (13:35:37) : Just so people know, yes I have trashed some comments attacking Dr. Svalgaard.”””’
CTM,
Vigilance is appreciated. Thanks.
John
The sun giving birth to another planet?.
Bode’s Law-distance each Planet is from the Sun.
http://ksssm.files.wordpress.com/2009/04/table-jpg.jpg
When you take into account the 9 planet’s quasi distance from the sun increases in a logarythmic fashion.
Coincidence?-225 million years Galactic circuit-divide by 24=200 mil. years
The Birth and the Ruin of the Planets of the Solar System
By Ilya Stavinsky.
http://uweb.superlink.net/~dialect/stars.html
http://tinyurl.com/yeqxqwa
”””’Suranda (14:02:43) : . . . . I just think the picture here is much wider and massive, than anything we ever thought possible, or believable. Our resources as human beings, are really, well and truly limited.”””’
Suranda,
Thank you for leading into a favorite subject of mine.
I would rather use the concept of identity instead of concept of limit in assessing homo sapiens capability to know the universe.
It is one thing to say man’s knowing capability has a specific nature [like everything that exists has a specific nature], it has a fundamental identity. We can know only within the specific nature of our knowing facility. However, it is another thing entirely to say there is a limit to what we can know. To state we have knowledge of limits of knowledge [things we cannot know] implies one already has knowledge of what cannot be known, so inherent error in the statement itself.
Getting down into the bowels of metaphysics and epistemology here. I love it. : )
John
tallbloke (15:52:04) :
At some point, the turtles rest on assumptions about which way is down, and how far “all the way” is.
No, the little old lady was quite firm on this.
James F. Evans (16:29:09) :
Temperature is unorganized, random atomic motion. That’s why a iron magnet will lose it’s magnetic field when heated.
These observations tends to discount Dr. Svalgaard’s hypothesis.
Temperature causes convection which is a very organized motion, with hot stuff rising and cold stuff sinking.
Gravity is an attraction toward a central point, not a side to side motion.
Gravity causes a river to flow 1000 miles towards the sea. But, apart from that, the gravity that create currents does that by pulling downwards and forcing the plasma across horizontal magnetic field lines [see you Low paper you quoted].
Yes, the Biermann battery mechanism, a type of internal dynamo.quoting yourself?
The Biermann battery effect does not operate in the Sun.
seem to contradict the first passage and open the door to a higher level of ionization at the surface of the Sun, the photosphere.
It does not. It is very specific about that. The 6400K was about the Universe.
Man is not privileged to know how the Universe started
He knows, nevertheless. You may not know. That is a problem with you.
“An electromotive force [mathematical equation] giving rise to electrical currents in conducting media is produced wherever a relative perpendicular motion of plasma and magnetic fields exists.” — Dr. Anthony L. Peratt, Los Alamos National Laboratory
And, that is where the Carlqvist & Alfven paper started and where the One & Mann paper started. And, when pressed, you acknowledge.
Not when pressed. This is what I have always said: move a conductor across a magnetic field and you generate a current.
So, Dr. Svalgaard, why do you obfiscate with words like “rain” and “cloud”? And, why do you carry on without mention of electromagnetic forces?
We use descriptive words without being confused by them, like the solar ‘wind’, and as I said whenever a conductor is moved across a magnetic field, e.g. falling down like rain [that is pulled by gravity] an electric current may be generated [if there are charges to carry the current.
Plasma can be quasi-neutral, with equal numbers of free electrons & ions in random distribution.
Not ‘quasi’. As long as there are equal numbers, it is neutral. Salt dissolved in water has equal number of Na+ and Cl- ions and is very neutral.
Again, Dr. Svalgaard, the two papers make quite clear the filaments are plasma animated by electric currents.
Science does deal with animated matters. The two papers very clearly [as I shoqed by quoting the relevant passages, that it motions of the plasma generate the currents, and that therefore the currents are consequences rather than causes. One can, of corse, call that ‘animation’ as long as it is clear what causes what.
Why are you so resistant to this proposition?
I’ve been trying to teach you this for months…but you refuse to learn…
aping does not become you, but the answers are that you have things backwards and that your propositions are nonsense, and I’m pretty resistant to nonsense.
Carla (13:27:57) :
But, looks good so far Leif.
You’re ok with most of this, aren’t you Evans? (I hope so, or I will need a glass of wine and a smoke geesh)
I don’t think he understood any of it, judging from his posts. You better reach for that glass of wine.
Leif Svalgaard (18:06:53) :
Cleaning up a sentence:
Science does NOT deal with animated matters. The two papers show very clearly [as I showed by quoting the relevant passages], that motions of the plasma generate the currents, and that therefore the currents are consequences rather than causes. One can, of corse, call that ‘animation’ as long as it is clear what causes what.
Leif Svalgaard (12:29:03) :
Leif Svalgaard (09:15:25) :
“OK, we can then continue.
9. The delicate balance between gravity and the magnetic field can be upset in several ways, e.g.
10. A new active region can emerge nearby, adding to or disturbing the existing magnetic field [like twisting the support of the hammock you a relaxing in]
11. Alfven waves travelling up the legs of the magnetic field [caused by twisting/movements of the foot points by the photospheric plasma pushed around by convection can also upset the balance and add energy to the configuration”
This comment gives Dr. Svalgaard’s game away (why he is so bound & determined to deny the electrical current flowing in the filament).
The “twisting” magnetic fields are consistent with the behavior of magnetospheric Birkeland currents which Science understands & accepts are electric currents.
The electromagnetic dynamics of the Birkeland currents cause them to rotate like giant tornadoes. There is no “feet” twisting them to cause the morphology of “twisted ropes”.
Dr. Svalgaard’s point 9 and 10 are a predicate to justify so-called “magnetic reconnection”, a pre-space age (1946) speculation.
You see Hannes Alfven identified these filaments as often stretching into flares or CME’s where explosive release of energy occurs. And Alfven identified the filaments as electric currents, or “the electric circuit model”, seconded by the One & Mann electric circuit model and also, modelled double layers as the cause of the explosive release of energy.
“The study of these alternative approaches (Alfven, 1968, 1979a) shows that the current description is necessary for the understanding of the formation of double layers, explosive phenomenon, and transfer of energy from one region to another.” — Carlqvist & Alfven
See plasma double layer:
http://en.wikipedia.org/wiki/Double_layer_(plasma)
But to allow that the filaments are electric current (and behaving as electric currents which twist and show a morphology of twisting magnetic fields), then opens up the door to Hannes Alfven’s Electric Double Layer as the mechanism for the release of the energy and not so-called “magnetic reconnection”.
Title: The Alfven-Carlquist double-layer theory of solar flares
Authors: Hasan, S. S. & Ter Haar, D.
Journal: Astrophysics and Space Science, vol. 56, no. 1, June 1978
http://articles.adsabs.harvard.edu//full/seri/Ap%2BSS/0056//0000092.000.html
Partial Abstract: “We discuss the applicability of this theory [The Alfven-Carlqvist double layer theory of solar flares] to solar flares, and show that conditions in solar flares may be such that double layers can exist…”
“These particles will be accelerated in the double layer and may in this way account for the production of high energy particles during the impulsive phase of solar flares.”
I’m sorry, But Dr. Svalgaard’s ‘lecture” is designed not to inform the readers of the physical relationships of filaments, but to justify and protect the failed “magnetic reconnection” model.
That is why Dr. Svalgaard has given the the electric circuit model short shrift (acknowledging the filament’s electric current when pushed into a corner, but quickly going back to his mechanical model, so that double layers can be ruled out and so-called “magnetic reconnection’ can be justified).
It makes one shake their head — this is not science, this is protecting a failed theory (and most likely protecting grant money).
Again, Dr. Svalgaard’s points 9 and 10 have no basis in physical reality other than to justify a failed theory.
Flowing electric current causes twisting magnetic fields — Science knows that from the study of magnetospheric Birkeland currents that have a twisted magnetic field and are known to be charge-seperated, charged particle flows, electrical currents.
From NASA:
“A “magnetic rope” is a twisted bundle of magnetic fields organized much like the twisted hemp of a mariner’s rope. Spacecraft have detected hints of these ropes before, but a single spacecraft is insufficient to map their 3D structure.”
http://science.nasa.gov/headlines/y2007/11dec_themis.htm
Solar flares also have a helical twisted morphology.
And, it is not because they are mechanically twist at the feet but that thoughout the entire circuit of the electric current there is twisted magnetic field.
Recently, twisted magnetic fields have been detected below the surface of the Sun.
“The quasineutral plasma model proposed by Langmuir more than 75 years ago is still widely used today and is based on two approximations: charge neutrality and the Boltzmann relationship for electrons.”
http://pre.aps.org/abstract/PRE/v71/i2/e026401
The use of the term “quasi-neutral” to describe plasma is appropriate.
”””’tallbloke (15:52:04) : At some point, the turtles rest on assumptions about which way is down, and how far “all the way” is.”””
”””’Leif Svalgaard (18:06:53) : No, the little old lady was quite firm on this.”””
Bertrand Russell had some baggage to carry around. He was perhaps the prototype of some of the current scientists who are active as economic/political/social advocates. (ie Hansen)
Philospohically Russell was an heir of the Plato-Kant-Hegal basis. Curious credentials for pursuing objective science.
John
James F. Evans (18:39:39) :
9. The delicate balance between gravity and the magnetic field can be upset in several ways, e.g.
The “twisting” magnetic fields are consistent with the behavior of magnetospheric Birkeland currents which Science understands & accepts are electric currents.
The ‘twisting’ was meant as one way of generating Alfven waves. I could have said ‘plucking’, ‘shaking’, ‘bobbing’ or any number of words indicating motion. The currents in the filaments are not Birkeland currents. And Birkeland currents are not ‘tornadoes’ [word used by someone objecting to ‘clouds’ and ‘rain’…].
As I said, the magnetic configuration can be disturbed by many things, all involving bodily movement of the plasma in the photosphere, eventually followed by reconnection in the corona to create a new topology of the field.
One more time: as Carlqvist, Alfven and everybody else who knows anything about this, electric currents are very much involved. Without they nothing would happen. The currents [as Alfven said] are generated by motion of the plasma across magnetic field lines and are thus consequences rather than causes of the filament. Let me quote again: “photospheric motion in the presence of magnetic fields produces voltage differences […] and a current starts to flow”. Note that the motion precedes the current. Onel & Mann: “Due to the photospheric plasma motion [with velocity u across the magnetic field B] the Lorentz force q u x B acts on the charges q of the plasma and leads to generation of an electric current”.
What can be more clear as to what causes what?
Leif Svalgaard (12:29:03) :
OK, so now we can continue.
12. The falling plasma [see http://www.youtube.com/watch?v=zbPNcjj__iE&feature=related ] cross the horizontal magnetic field lines. They can do this in spite of the frozen-in condition because they are cool and the ionization is only partial.
13. a conductor crossing a magnetic field generates an electric field. The force equation is F = q(E + v x B), from which we get the electric field E = F/q – v x B; http://en.wikipedia.org/wiki/Lorentz_force
14. a current will now flow. Since the quantities are vectors they have a direction. With v vertically down [gravity], B horizontal [has to connect two opposite polarities in the photosphere, E will be perpendicular to both, i.e. along the filament.
15. Magnetic field on the sun are often twisted and have a weak helical structure. This ‘helicity’ is opposite in the two hemispheres [and does not change with the changing polarities of the solar cycle] and is likely caused by the solar dynamo twisting the field [Hurricanes also twist oppositely in the two terrestrial hemispheres].
16. So filaments often have a slight twist to them. The twist actually helps stabilize the filaments a bit.
James F. Evans (19:08:53) :
is based on two approximations: charge neutrality and the Boltzmann relationship for electrons.
Charge neutrality means neutral. And [as the paper you cite says] the Boltzmann relationship is unnecessary and is not always justified.
These are just words. The physics is that if you take a macroscopic volume there are no measurable difference between the number of positive and negative charges. If there were, the resulting strong electric field would short out immediately, restoring neutrality. Here is the definition of charge neutrality: “The approximate equality of positive and negative particles in high-density plasmas.This phenomenon, which is sometimes called electrical neutrality, is a result of the extremely large electric space charge fields that would arise if the densities were not equal. Although the positive and negative charge densities are seldom exactly equal, their percentage difference is so small as to be negligible. It is not difficult to maintain this condition in an active plasma since ionization or recombination always produces or destroys an ion pair together.” This will hold even more in low-density plasma as the mobility of the particles are much higher.
John Whitman (19:18:00) :
Philosophically Russell was an heir of the Plato-Kant-Hegel basis. Curious credentials for pursuing objective science.
Russell was a mathematician. Proved that 1+1 = 2.
Take a look at the rotating Sun here: http://www.koeri.boun.edu.tr/astronomy/
Shows lots of giant filaments at solar maximum.
Leif Svalgaard (19:41:37) :
OK, so now we can continue.
17. If the change in the magnetic topology is rapid enough, the current generated by the change can be very strong and lead to vigorous heating of the filament with resulting rapid expansion into the corona, a coronal mass ejection [CME].
18. The CME rises, but gravity resists the expansion initially. However gravity gets weaker with height and the gravitational restriction is gradually lifted and the CME eventually reaches supersonic speeds and escapes into the solar wind.
19. In spite of this escape, the magnetic field lines frozen into the CME are still firmly rooted in the photosphere even as far away from the Sun as the Earth, resulting in a long ‘magnetic tongue’ reaching far out in the heliosphere.
@ur momisugly Carla (13:27:57) Thanks for collating to this point. I’ve copied for ease of reference. Lotta noise in this signal…
point 18 – Supersonic as based upon the speed of sound?
Leif Svalgaard (18:06:53) :
tallbloke (15:52:04) :
At some point, the turtles rest on assumptions about which way is down, and how far “all the way” is.
No, the little old lady was quite firm on this.
Thanks Leif, good to know who we are relying on for the epistemological basis of our conceptions of the universe.
Leif Svalgaard (20:19:31) :
John Whitman (19:18:00) :
Philosophically Russell was an heir of the Plato-Kant-Hegel basis. Curious credentials for pursuing objective science.
Russell was a mathematician. Proved that 1+1 = 2.
The firmament of scientific intellect isn’t so neatly divided into labelled constellations as you like to think. The course I did on the development of European science, and the course on methods and problems in historiography revealed al sorts of interesting influences on the thinking of apparently ‘objective’ practitioners.
Roger Carr (22:02:26) :
Lotta noise in this signal…
Leif is at his most informative when being challenged. My thanks to all contributors to this thread.