The great filament

Jim Steele (16:33:15) :
However I can see that you have lumped me in with others with whom you disagree.
Jim, I sincerely apologize for lumping you in with the others. That was an unwarranted knee-jerk reaction of mine, for which I’m sorry and for which I hereby apologize.
Has Alfven fallen from his Nobel heights, and is now deemed to also be a “nut” by modern physicists?
No, Hannes Alfven was a god and dear friend of mine and although many of his ideas are no longer supported, his contributions were many and varied and often important. Some of them have been hijacked by the fringe which would make him cringe.
And mainstream explanations that refer only to magnetism always seem like only half of an explanation.
The reason is simple: An electric field depends on the reference frame of the observer while the magnetic field does not. So, the two are not ‘equal’. In a highly conducting plasma, a magnetic field is ‘frozen’ into the plasma and moves with the matter [this was Alfven’s great discovery]. If the conductivity in certain regions of the plasma for various reason drops, the magnetic field is no longer tied to the plasma; this ‘thawing’ of the field under the correct circumstances has important consequences for the interaction of the plasma with bodies embedded in it, as electric fields can briefly occur – Alfven railed against the idea that the field was ‘always’ and permanently ‘frozen’ into the plasma and stressed that the thawing of the magnetic field was at times important – something that people did not always appreciate some 40 years ago. Today we are heeding his words and do things correctly in ways he would certainly approve of.
I simply ask what causes the magnetic fields to change? Changes in plasma flow? Why does the magnetic fields create the filaments where they do?
Since the magnetic field near the surface of the Sun is controlled by the plasma [the magnetic energy is much less than the kinetic energy of the roiling solar plasma] when the plasma moves the magnetic field is dragged along and the magnetic configuration [the field lines show the shape of the field] can change rapidly. And the plasma is in constant motion, mainly because there are large convective motions [like in boiling water]. Imagine a magnetic field line going from one sunspot up into the atmosphere and then curving down into an adjacent spot [this is the typical configuration]. The density in the solar atmosphere decreases rapidly with altitude [just like in the Earth’s atmosphere], so the kinetic energy of the plasma decreases with height much faster than the magnetic energy to the point where eventually the magnetic field becomes the dominant force and guides the plasma flow [you have likely seen images of material flowing along the field lines]. This means that the magnetic field is now containing the plasma and the filament can form in the upper part of the magnetic loops. It also means that on either side of the filament the magnetic field will have opposite polarity [up one leg of the loop and down the other leg], so filaments marks large-scale ‘neutral lines’ between regions of opposite polarity. It is opposite polarities that can reconnect and interact, so filaments are places where explosions can occur, hence the flares.
Such explanations also imply there can not be separation of charges in space plasmas.
This is indeed correct, but with one important caveat: namely that the particles be allowed to stream freely [see below].
But that contradicts my understanding of the Van Allen belts in which it is observed that the outer belt is mostly negative electrons and the inner belt is mostly positive ions. Doesn’t that create an electric field?
The charged particles in the belt are trapped by the strong magnetic field of the Earth and are constrained to spiral along the field lines, bouncing from pole to pole, so are not moving freely and can therefore not neutralize. So you get an electric field from the charge separation, but this field does not control the movement of the particles – the magnetic field does.
The intensity of your reaction
I again apologize for the reaction
makes me wonder if there is a culture within mainstream astro/solar physics that has decided to only speak in terms of magnetism as a gate-keeping mechanism to keep out the fringe proponents of a more electric view.
There are no conspiracies here. It is Mother Nature that uses magnetism as the gatekeeper. All serious physicists are in agreement on this [there are always a few that have fallen off the cliff]. The Electric/Plasma Universe folks seem to be driven by underlying agendas of various kinds – religious, political, new-age, etc or simply by the urge to seek explanations that are easy and visual and does not require mathematics or any deeper knowledge [which is hard work to acquire]. These will of necessity be superficial and not represent real knowledge. This dumbing-down of the populace is dangerous to a society that ultimate must rely on since for survival, as we have exhausted the easy picking of the low-hanging fruit. A god example is the very next comment(s), where real knowledge is called ‘dogma’:
Suranda (16:37:34) :
Dogma is dangerously seductive. And anti-science.
James Evans statement above sounds like the voice of integrity. It should be addressed by you scientific dudes, I think.
Jim Steele (19:25:25) :
Another question about filaments. Is the magnetic polarity always the same, say south at the equator and north towards the poles, or does it vary randomly or does the polarity alternate each cycle along with the alternation of sunspot polarity?
Sunspots follow a set of polarity rules as you state [changing with the cycle, etc]. Filaments [as explained above] lie between regions of opposite magnetic polarities, so follow along with the changes of the spots.
Jim Steele (19:27:57) :
And 1 more, do filaments always align as seen here, assuming also a mirror image in the northern hemisphere. Or do they ever align parallel to the equator?
They can have any orientation, although at low latitudes the often go North-South. There is a special class of filaments called the ‘polar crown’ that encircle the North and South poles, along the boundaries of the polar coronal holes. Magnetic fields from decaying sunspots are swept [remember: the plasma moves the field around] by a meridional circulation [the Earth also has that] from lower latitudes towards the poles and a rather strong magnetic field then tends to build up there. This polar magnetic field eventually becomes the seed of the next sunspot cycle.
NickB. (21:39:27) :
whenever you take a drink of cool refreshing water chances are you’re drinking at least a few molecules of dinosaur pee
And of Jesus pee.

James F. Evans (01:33:47) :
The author clearly identifies the filament as being an “electric current”.
This is a typical example of the twisting of science to conform to wrong physics. Such twisting occurs can occur when the physics is not understood. Nowhere does the author identify the filament as being an electric current. [one might ask for page and line number for such identification]. What does happen is that when external forces deform a magnetic field and the weight of the filament [caused by gravity] does just that, small electric currents are induced. This happens everywhere where there is a dB/dt [that is: a change of the magnetic field]. The fundamental issue is that electric fields are generated by plasma [a conductor] moving in a magnetic field. The electric currents are precisely the neutralization of this electric field preventing the electric fields building up.

Jim Steele (09:43:57) :
It is easier for me to conceive of this with more solid bodies helping to “freeze” and maintain the magnetic fields for extended periods.
‘Freezing’ is perhaps not a good word for this, but our language lacks words for things we do not experience; we do not live in a plasma, so have no word for this. What happens is that a changing magnetic field generates an electric field. In a highly conducting plasma, the electric field is shorted out immediately and there can thus not be a sustained electric field, thus no change in the magnetic field. In our daily life we never come across such phenomena and thus have no intuitive understanding of them. A little anecdote might illustrate that we can actually in rare cases observe this directly. I was once standing next to a cyclotron that used powerfull magnets to bend the trajectories of ions. Because of the magnets, no iron tools were used near the cyclotron. There was a bucket for the use of the janitor to clean up spills. The bucket was made of copper. By accident I caused the bucket to tip over. In ordinary life, it would take it but a fraction of a second to fall, but because copper is such a good electrical conductor and because the bucket was immersed in a strong magnetic field, the field was ‘frozen’ to the bucket and the bucket couldn’t fall but had to stay in its position. Copper, however, does have a finite resistivity and the freezing was not perfect, so the bucket did fall, but it took about five seconds to do it [as eddy currents in the copper slowly dissipated]. In cosmic plasmas the conductivity is much higher and the linear dimensions much larger [it turns out that is important too], so the freezing in much more effective.
The biggest question is what is the evidence to suggest a new sunspot has arisen from an old spot? I can’t imagine how that could be proven, so I suspect that notion is more of a logical extension of a model.
It is, of course, not the case that a specific new spot has arisen from a specific old spot. Raindrops are recycled water from previous raindrops, but that does not mean that a specific raindrop that falls on your head now has arisen from a specific drop that fell into a river, was carried into the ocean, evaporated, went into a cloud, and reformed to fall on your head. Same thing with the magnetic fields from old sunspots. A piece of the field is frozen into a blob of plasma and dragged over the solar surface. The plasma partakes in a circulation that carries it into the Sun near the poles and in there circulates to lower latitudes. Since magnetic fields have no ends, some segment of the field lines are outside the blob and are not dragged along with the blob [or dragged with a different speed or direction] and then become stretched and would around by solar rotation. Imagine it is wound around ten times then through a given area perpendicular to the field line, where there before were only one line, there are now ten, so ten times a many field lines results from the winding. Now, the magnetic field strength is simply the number of field lines per unit area, so the field is now ten times stronger. [some people don’t like the image of ‘field lines’, although it is very appropriate in this situation; they prefer to think of just the field strength being amplified as described by a mathematical equation – either way, the result is the same].
All this winding takes place inside the Sun where we cannot see it directly. But just as we can use waves from earthquakes [or man-made explosions] to image the interior of the Earth [and prospect for oil], we can also ‘see’ the distortions of the solar interior braought about by the wound-up field by observing sunquakes. We can, in fact, see ‘through’ the Sun and watch sunspots forming on the backside of the Sun.
A magnetic field exerts a pressure of its own [try to press two magnets together same polarity to same polarity] and so a wound-up strong field has an appreciable pressure of its own. A parcel of plasma surrounded by other plasma must be in pressure balance with its surroundings. If some of that pressure comes from the magnetic field that doesn’t weigh anything, the parcel must contain less material and is thus lighter than the surrounding parcels [with no magnetic field]. This like releasing a piece of wood in water from a depth of, say, a yard: the wood will rise to the surface. Likewise, the magnetic field and when it does a sunspot can form from it. So, as from one raindrop to another later on, it is from one magnetic field to another later on.
That the polarity changes is a bit harder to understand [but only a bit]. Sunspots occur in pairs [simplification, but close enough] with each spot of a different polarity. Observationally [and theoretically as well] we found that the line or axis connecting the two spots is tilted slightly so that one spot [we call that the ‘following’ spot] is at a higher latitude than the other spot. Imagine the fraying spots spreading the fields out over an area around the spots then there is a bigger chance that more of the field that is already at a higher latitude will survive the journey to the pole [it has a shorter way to go] and thus the poles will tend to accumulate preferentially the fields from the ‘following spots’. Now, drag that field inside the Sun, wind it up, and let it [like the wood] resurface years later. If you make a little drawing and keep track off the direction of the field lines, you’ll find that the direction reverses in this process [seen from the outside], so the new spots will have opposite polarities from the old spots.
Why doesn’t the roiling plasma disrupt the magnetic seed.
Because the magnetic field has a linear extension many times larger than that of the ‘roiling’. When you throw a pebble in the ocean you create small circular waves spreading out from where the stone hits the water. These little ripples do not disrupt the monster ocean waves that surfers ride.

James F. Evans (12:42:12) :
if the “internal electric current” is not flowing along the length of the plasma filament from one foot to the other foot, where does the electric current flow to and from?
This is the kind of question that stems from you not understanding the paper or the physics. The filament hangs in a magnetic ‘arcade’ which exists before and after the filament. The magnetic field [as the paper says] may be thought to be produced by a line current [“in the negative x-direction”] located at some distance below the surface. This is just a convenient way of describing the magnetic potential by ‘an equivalent current’ [just like the HCS] . Now, gravity is pressing the filament down across the horizontal field lines. That generates a current in the opposite direction [as the paper clearly describes “in the positive x-direction”]. This current induces “an image current” below the corona, and the resulting configuration is derived from the sum of all the Lorentz forces resulting from these currents. So, again, the currents are not generating the filament, but gravity pressing down on the filament is generating the currents. The arcade is there with or without the filament and does not owe its existence to the filament. So, your statement ‘The plasma flows in the filament is due to the ‘internal electric current” is backwards, as usual.
If you don’t like my analog with the flea, think of the bacteria in your stomach and its output channel forming an internal constituent of you, without which you couldn’t live.