Flux Ropes in the Solar Wind

[upriver]

The reason for the question is that I found numbers on how fast the particles move in the aurora, and it's 60,000 km/s, which is 1/5 the speed of light! And I'm having a hard time justifying that kind of acceleration just with an attraction of the electrons in the solar wind to the positively charged ionosphere. Perhaps that's it, but I starting to think that there has to be more to it than that, and a magnetic attraction would seem to be the only other candidate.

Charles, Can't the radial electric field in a Birkeland current filament be stronger than the field driving the current in the first place?

The reason for the existence of flux tubes and arcs etc is because the local medium/plasma is not dense enough to handle the current flow between the objects of differing potential. The "reconnection" machine RDX demonstrates that.

It may be that to form a flux tube you have to keep feeding it plasma from the originating object.... Lightning is different in that it uses the local high pressure medium to transfer charge where as a flux tube is generally formed at low pressure...

Upriver,
Comments on the following? http://onlinelibrary.wiley.com/doi/10.1 ... 2/abstract
It does seem to be that the local medium/plasma density is great enough to maintain Birkeland currents? Which of course means that magnetic fields between particles, is greater than the background magnetic field. And this in the plasma tail under normal conditions? All I'm trying to establish here is whether we all agree on whether charged particles from the sun, enter the Earth's magnetic field as Birkeland currents, or as a sea of charged particles streaming radially from the sun. Either way, I think we all agree that charged particles streaming radially from the sun (in Birkeland currents or not), end up as charged particles streaming along magnetic field lines into Earth's poles?

I would probably lean towards a flux tube being the main power source with some solar solar wind getting in at the magnetospheric poles.
Something called a flux transfer event indicates that a flux tube is connected to the magnetosphere. A flux transfer event is just a periodic pinch(reconnection).

"Dec. 16, 2008: NASA's five THEMIS spacecraft have discovered a breach in Earth's magnetic field ten times larger than anything previously thought to exist. Solar wind can flow in through the opening to "load up" the magnetosphere for powerful geomagnetic storms. But the breach itself is not the biggest surprise. Researchers are even more amazed at the strange and unexpected way it forms, overturning long-held ideas of space physics.
"At first I didn't believe it," says THEMIS project scientist David Sibeck of the Goddard Space Flight Center. "This finding fundamentally alters our understanding of the solar wind-magnetosphere interaction."
The magnetosphere is a bubble of magnetism that surrounds Earth and protects us from solar wind. Exploring the bubble is a key goal of the THEMIS mission, launched in February 2007. The big discovery came on June 3, 2007, when the five probes serendipitously flew through the breach just as it was opening. Onboard sensors recorded a torrent of solar wind particles streaming into the magnetosphere, signaling an event of unexpected size and importance."
http://science.nasa.gov/science-news/sc ... antbreach/

Birkeland currents are the result of the local medium being unable to sustain a current flow between two charged objects. They naturally want to equalize and the quickest way to do that is with a birkeland current(thats what I am going to say without invoking an Aether).
The pressure at the surface of the sun is lower than the best vacuum we can produce on earth although that may have changed. I cant seem to find a current vs pressure curve for a glow discharge...

[upriver]

Cluster Multi-Spacecraft Observations of Flux Transfer Events

http://www.mssl.ucl.ac.uk/www_astro/aca ... thesis.pdf

[upriver]

I am beginning to suspect that reconnections act like a natural regulation mechanism.

[CharlesChandler]

I am beginning to suspect that reconnections act like a natural regulation mechanism.

Regulating what? I could see how some of the lines of force in the aurora's polar cusp might reconnect to the solar wind if it was strong, and then go back to their toroidal form if the solar wind was weak. This would make it like a SPST switch regulating the current in the HCS, by shunting excesses into the aurora. From there, the current goes into the Van Allen capacitor, which slows leaks the charges back into the solar wind. So the HCS would get regulated.

[upriver]

I am beginning to suspect that reconnections act like a natural regulation mechanism.

Regulating what? I could see how some of the lines of force in the aurora's polar cusp might reconnect to the solar wind if it was strong, and then go back to their toroidal form if the solar wind was weak. This would make it like a SPST switch regulating the current in the HCS, by shunting excesses into the aurora. From there, the current goes into the Van Allen capacitor, which slows leaks the charges back into the solar wind. So the HCS would get regulated.

Specifically Flux transfer events but even reconnections in general. I dont know if the earth dissipates enough energy to regulate the HCS. I believe extra solar energy is dissipated in the Heliotail...
But just think if you dumped energy continuously into the earth system from the sun. It would have to discharge at some point assuming there was no outflow or resistance to transform charged kinetic energy(solar wind) into neutral kinetic energy or heat.... And we do see earths magnetotail tapering off in a gradual dissipation of energy.

Do flux tubes have quantized sizes????

[CharlesChandler]

But just think if you dumped energy continuously into the earth system from the sun. It would have to discharge at some point assuming there was no outflow or resistance to transform charged kinetic energy(solar wind) into neutral kinetic energy or heat....

I'm thinking that there is a net negative current into the Earth in the aurora, and out of the Earth nearer the equator, which populates the outer Van Allen belt. From there, the electrons leak back into the HCS. In the magnetotail, they become Birkeland currents again, and re-open the magnetic field lines as they stream away, turning the Earth's toroidal field into a pancake, the same way they do in the tips of the helmet streamers, flattening the Sun's toroidal field into the HCS.

Do flux tubes have quantized sizes????

They begin as the same size as granules, and then expand from there. I forget the typical width at 1 AU, but they're something like 10x wider. But I don't think that this is what you mean by quantized. Do they get wider in steps? I don't see why they would, and I haven't heard that they do.

[celeste]

The reason for the existence of flux tubes and arcs etc is because the local medium/plasma is not dense enough to handle the current flow between the objects of differing potential.

Thank you. I just realized that a flux tube is just a special case (low plasma density), of a Birkeland current, following the rules of Donald Scott's filament model.

(Now I also understand the flow in the "water bridge", it is a high particle density extreme of the same filament model).

Upriver, I know you're familiar with flux tubes, but are you familiar with Scott's magnetic filament model, AND Chandler's electrostatic filament model? If you understand both, I'll show you how easily this goes together. All you need from the water bridge, is to note that they found the ions at the surface to be spiraling very much around the filament axis. This would indicate a nearly azimuthal field in Scott's model. Flux tubes are known for their nearly axial magnetic fields at the surface (parallel to the tube's surface). The water bridge, clearly had a high density of charged particles. As you say, the flux tube is a very low plasma density object.
In Charles' electrostatic filament model, greater particle density, means more force to hold our particle to the filament, which means the faster it can spiral around the filament without "flying off". In other words, it can travel down one of Scott's filaments where the field is very much azimuthal. This is what we see at the outer radius of the water bridge. If, on the other hand, we have very low particle density, we only have electrostatic forces to maintain a slowly spiraling filament. That filament "fails" unless we have a nearly axial field (particles flow along a nearly axial magnetic field at the surface). That IS a flux tube.

[CharlesChandler]

In Charles' electrostatic filament model, greater particle density, means more force to hold our particle to the filament, which means the faster it can spiral around the filament without "flying off". In other words, it can travel down one of Scott's filaments where the field is very much azimuthal. This is what we see at the outer radius of the water bridge. If, on the other hand, we have very low particle density, we only have electrostatic forces to maintain a slowly spiraling filament. That filament "fails" unless we have a nearly axial field (particles flow along a nearly axial magnetic field at the surface). That IS a flux tube.

I'm not sure that I understand "my" electrostatic filament model. Electrostatics won't create filaments. Only electrodynamics can create filaments in plasma. You need an electric force to get the charges moving, but it has to be strong enough, and/or the resistance has to be low enough, for the charges to move at excessive speeds. Then the magnetic pinch effect kicks in, and consolidates the particles, in spite of their electrostatic repulsion from each other. If, for whatever reason, the motion is stopped, the magnetic field goes away, and all you're left with is the repulsion, which then disperses the plasma.

For that matter, now I'm not sure I understand Don Scott's filament model, if it's different from what I just said. Can you briefly state Scott's model, and where (if at all) it differs from what I just said?

Cheers!

[upriver]

But just think if you dumped energy continuously into the earth system from the sun. It would have to discharge at some point assuming there was no outflow or resistance to transform charged kinetic energy(solar wind) into neutral kinetic energy or heat....

I'm thinking that there is a net negative current into the Earth in the aurora, and out of the Earth nearer the equator, which populates the outer Van Allen belt. From there, the electrons leak back into the HCS. In the magnetotail, they become Birkeland currents again, and re-open the magnetic field lines as they stream away, turning the Earth's toroidal field into a pancake, the same way they do in the tips of the helmet streamers, flattening the Sun's toroidal field into the HCS.

When I look at Van Allen diagrams I see more of a shell that is populated by the influx of plasma at the megnetospheric foot prints near the poles as well as there is a flux tube that extends from the flux transfer point into the magnetosphere.. The only thing that I see at the equator is the South Atlantic Anomaly which I believe is an inflow..

The South Atlantic Anomaly

http://www.bibliotecapleyades.net/cienc ... nges49.htm

Van Allen Belts: How Little We Knew
"NASA launched the project’s identical satellites (originally christened the Radiation Belt Storm Probes) on 30 August 2012. The next day, a major coronal mass ejection erupted from the Sun. The researchers rushed to turn on the Van Allen Probe sensors, a month ahead of schedule. First to go online was the Relativistic Electron-Proton Telescope (REPT), designed and built by a 25-person team led by the University of Colorado’s Dan Baker. Its data revealed a radiation belt no one had anticipated.



In Science, Baker and colleagues report that the probe revealed a radiation structure that flickered and writhed like a candle flame in a stiff breeze. On 3-5 September, as stunning auroras blazed in Earth’s sky, the outer belt seemed to melt inward and compress into a tight, high-energy “storage ring” at an altitude of 13 000 to 16 000 km. Beginning on 7 September, the outer belt seemed to reassert itself, creating a new, three-ring, circuit.

Reletavistic Electron-Proton TelescopeREPT found the storage ring populated by energetic electrons—and especially those at the higher end of the energy spectrum, 6.2 to 7.5 mega electron volts. (The rest mass of an electron is about 0.51 MeV.)"
http://spectrum.ieee.org/tech-talk/at-w ... we-knew-ye

[CharlesChandler]

When I look at Van Allen diagrams I see more of a shell that is populated by the influx of plasma at the megnetospheric foot prints near the poles as well as there is a flux tube that extends from the flux transfer point into the magnetosphere.. The only thing that I see at the equator is the South Atlantic Anomaly which I believe is an inflow..

I should rephrase, having thought about it a little more, and done some more reading.

I believe that the aurora supplies neutral particles, and some free electrons, to the mesosphere. But with the Earth's net negative charge, free electrons are repelled, and are drifting outward. The footpoints of the Van Allen belts are just outside the footpoints of the aurora. But there is no glow discharge at the Van Allen footpoints. The reason is that the electrons will follow the magnetic lines of force away from the planet, just as they did when coming into the aurora, but while they were accelerated by the convergence of the lines of force in the aurora, their outward motion is braked by the divergence of lines in the Van Allen belts. So they cannot be accelerated back out -- you can't have it both ways -- the electrons are accelerated inward in the aurora, and them pumped by electrostatic repulsion into the Van Allen belts, against the diverging lines of magnetic force.

The radiation is closest to the surface about the South Atlantic Anomaly, because there, the electrons can flow outward, without having to fight againt diverging lines of force as they would at the poles, and without having to cross lines of force as they would at the equator. So they can flow outward just by electric pressure.

[celeste]

In Charles' electrostatic filament model, greater particle density, means more force to hold our particle to the filament, which means the faster it can spiral around the filament without "flying off". In other words, it can travel down one of Scott's filaments where the field is very much azimuthal. This is what we see at the outer radius of the water bridge. If, on the other hand, we have very low particle density, we only have electrostatic forces to maintain a slowly spiraling filament. That filament "fails" unless we have a nearly axial field (particles flow along a nearly axial magnetic field at the surface). That IS a flux tube.

I'm not sure that I understand "my" electrostatic filament model. Electrostatics won't create filaments. Only electrodynamics can create filaments in plasma. You need an electric force to get the charges moving, but it has to be strong enough, and/or the resistance has to be low enough, for the charges to move at excessive speeds. Then the magnetic pinch effect kicks in, and consolidates the particles, in spite of their electrostatic repulsion from each other. If, for whatever reason, the motion is stopped, the magnetic field goes away, and all you're left with is the repulsion, which then disperses the plasma.

For that matter, now I'm not sure I understand Don Scott's filament model, if it's different from what I just said. Can you briefly state Scott's model, and where (if at all) it differs from what I just said?

Cheers!

Charles,
Yes, we do need an electric force to get the particles moving, and then the magnetic forces kick in. Those magnetic forces are as described by Donald Scott here http://electric-cosmos.org/BirkelandFields.pdf
Donald Scott suggests (last of page 7,beginning of 8), that we can have a force-free current, anywhere the pitch angle is zero. That means we can have a "tube" of charged particles traveling along the z-axis, and the magnetic field at that surface is parallel to the tube. Note, that is what we see with flux tubes.
What is missing in Scott's model, is any mention of electrostatic, (or gravitational), forces working radially in the filament. The reason his model works, as is,for flux tubes, is because of that minimal plasma density. No great plasma density, no strong radial fields.
Going to the water bridge experiments, what they found, was that ions seemed to be spiraling rapidly around (more azimuthally, than axially down the filament),at the filament surface. The difference here, is we suspect a very strong radial field (they think it's negative charge traveling down the center in one direction, ions spiraling around the outside). The only way to balance a strong radial attractive force, is with spiraling of the outer layer. Not any different than the simple gravity only case, where a ring of material must orbit faster around the planet, the stronger the gravitational force is at that radius. Now note, the stable configurations must involve spiraling around the filament to balance electrostatic forces, and spiraling along the filament according to the magnetic
winding rate. (The stable radii come up the same way that Bode's law came from balancing gravitational forces with the magnetic fields,assuming our solar system was in one of Scott's magnetic filaments).

Charles, I'll have to get back with you when I find your relevant posts about the filaments. Can you remember where you addressed interstellar-scale filaments that were NOT in your opinion caused by any large scale EMF?

[CharlesChandler]

What is missing in Scott's model, is any mention of electrostatic, (or gravitational), forces working radially in the filament.

Well, you have to take electrostatics into account. A z-pinch will consolidate like charges, with a force that varies with the amount of charge and the speed at which the charges are moving. But even at the fastest speeds ever achieved inside particle colliders, the electrostatic repulsion between like charges was stronger than the z-pinch.

Can you remember where you addressed interstellar-scale filaments that were NOT in your opinion caused by any large scale EMF?

Bipolar jets IMO are ejecta from nuclear fusion reactions, and thus get along just fine without an EMF, and the z-pinch that keeps them organized is pretty obvious, until of course the jets have encountered enough friction in the interstellar medium that they slow down, and then the magnetic field relaxes, and the jets fall apart. Turbulence in gas cloud collisions can also result in filaments that are not electrodynamic in nature.

[celeste]

What is missing in Scott's model, is any mention of electrostatic, (or gravitational), forces working radially in the filament.

Well, you have to take electrostatics into account. A z-pinch will consolidate like charges, with a force that varies with the amount of charge and the speed at which the charges are moving. But even at the fastest speeds ever achieved inside particle colliders, the electrostatic repulsion between like charges was stronger than the z-pinch.

Charles, We do have to take electrostatics into account, and when we do, Dr. Scott's model really works to explain the observations. One problem with his model, was that it effectively goes out to infinity in radius, or at the very least, gave no mechanism for a determining an outer radius. Our real world filaments do have a definite radius. In the low density "flux tube", the outer radius was charged particles traveling axially, and an axial magnetic field at that radius. The high charge density water bridge had an outer radius with particles spiraling rapidly around the filament. The electrostatic forces determine the maximum radius. Again, a flux tube and a water bridge are just two extremes in Scott's filament model.
As far as the z-pinch: I was going to say Scott's model does not address pinches (he is only modeling a steady state, nearly cylindrical section of filament). But his model is the only one I've seen that can explain that "plasma stickman" figure. I think you may be arguing here against the idea of a pinch somehow concentrating mass into the center (like some ideas we've seen for star formation). Don't worry, Donald Scott isn't saying that, and more importantly, his model shows what is wrong with that idea.

Everybody,
I know I'm getting off track from the point of this thread, so I'll end it simply with the idea that "flux tubes" are just normal Birkeland currents, that have at their greatest radius an axial magnetic field. The only reason that wasn't more obvious , is I'm still conditioned to think of Birkeland currents as having azimuthal fields everywhere. It's a good idea to always keep Donald Scott's filament model in mind.

[celeste]

Charles, By your electrostatic model, I meant what you described here (I'm still searching your posts,for the best points)
http://www.thunderbolts.info/wp/forum/phpB ... =15#p90168
"Collapse into Filaments, and then into Stars
The whole dusty plasma doesn't converge radially into a single, central star. Rather, it resolves into filaments, which then collapse into one or more stars, sometimes creating a series of them, like beads on a string. Gravity doesn't favor filaments, and hydrostatic pressure hates them, so this is evidence of EM. I have shown elsewhere that in a linear filament, the like-likes-like force is stronger than the body force in a spherical arrangement of Debye cells. The reason is that in a filament, the positive and negative charges line up in an alternating sequence, where there are only attractive forces, as opposed to attractions and repulsions in a spherical arrangement. Thus if filaments form, they are more likely to collapse into stars. The filaments form on the edges of high-pressure jets coming from the supernova."


My point here, is that the "like-likes-like" is electrostatics, not electrodynamics. That works perfectly well WITH Donald Scott's magnetic model. Scott does not just assume that charged particles travel along magnetic field lines, he shows why they should evolve to that configuration. What this means, is that if charged particles are tending to flow along magnetic field lines (as opposed to spiraling around magnetic field lines), that the particles are in a magnetic force-free configuration. This means your ideas of electrostatic forces in filaments, are MORE applicable than if we had particles spiraling due to electromagnetic forces. This means we can isolate the forces involved.
This idea can be better illustrated when we talk about planetary orbits. Do planets seem to orbit around the sun according to laws that are some combination of 1/r^2 and 1/r, for example? As if we were seeing some combination of gravitational and magnetic forces acting on them? No. We can explain planetary orbits by a purely 1//r^2 force. The problem was, we could not get to Bode's law (why only some of those 1/r^2 orbits are allowed). What we are seeing is orbits where "gravity only" does explain the orbits, but only the subset where magnetic forces are zero (field aligned spiraling of planets)
Back to filaments, if we insist that charged particles spiral along the filament in a magnetic force-free configuration, what that means is that electrostatic forces are the only radial forces in the filament acting on the charged particles. In other words, it is not that electrostatic and magnetic forces push/pull our charged particles radially in a filament (once we've reached that force-free configuration) , but electrostatic forces alone will determine how fast charged particles must spiral around a filament. The magnetic field just determines which of these orbits (spiraling rates, if our particles are traveling down the filament) are stable.

[CharlesChandler]

Scott does not just assume that charged particles travel along magnetic field lines, he shows why they should evolve to that configuration. What this means, is that if charged particles are tending to flow along magnetic field lines (as opposed to spiraling around magnetic field lines), that the particles are in a magnetic force-free configuration. This means your ideas of electrostatic forces in filaments, are MORE applicable than if we had particles spiraling due to electromagnetic forces. This means we can isolate the forces involved.

I'm not so sure. Scott's paper (Magnetic Fields of Birkeland Currents) actually describes something that is far from what Birkeland was talking about. For example, Figure 6 (on page 8) shows a core and two shells. These are concentrations of negative charge traveling out from the paper, and generating magnetic fields by the left hand rule, which (somehow) resolve into three distinct regions, separated by the magnetic pressure from the opposing fields between like-charged shells. It appears that he got this configuration from plasma focus research, but this isn't a Birkeland current at all. When charged particles are moving along the lines of an external magnetic field, they spin around the lines of force, due to the Lorentz force, forming a true Birkeland current. For there not to be a spin, there has to not be an external magnetic field, in which case it isn't a Birkeland current. Even without the external field, the current that he's showing is fundamentally unstable -- the magnetic pinch effect favors an homogenous concentration of like charges in the center. IMO, what he's showing can only be created by a contrived apparatus, in which case it doesn't speak to in situ astrophysical conditions. It also assumes rather than states that the current in question had to be motivated by an electric field, in this case between the negative charges involved in the current moving toward a concentration of positive charge. He then shows a picture of the Butterfly Wings Nebula (M2-9), and calls attention to the concentric shells, suggesting that it is a "current" of the same layered configuration, not realizing that this begs more questions than it answers. First and foremost, what created the concentration of charge in the center that would attract the current? Second, how did that attract perfectly symmetrical and diametrically opposed currents, instead of just pulling in the desired charges radially? Third, what is the physics behind this layered configuration in situ (i.e., not in a focus fusion experiment)? All in all, I don't think that he actually connected any dots in that paper, so I'm not going to rest anything on it.