THE SUN'S DENSITY GRADIENT

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The Sun's Density Gradient

Post by CharlesChandler » Mon Jan 23, 2012 2:59 am

Somewhere on the short list of inexplicable properties of the Sun, there is the question of what causes the distinctive density gradient. Only taking gravity and hydrostatic pressure into account, the density of a gas in space should fall off with the square of the distance from the center of gravity, producing a (more or less) straight line on a log graph. From the center of the Sun out to the edge of the photosphere, this is precisely what happens. But the fall-off should continue on that straight line to infinity, which is not what happens. At the surface, the density drops off sharply, as if the plasma is inside a sealed container.

Clearly, powerful forces are at work, to maintain the higher-than-expected density out to the edge, and then for the density to drop off suddenly to almost nothing. Obviously, the gravitational model cannot explain this, and calling the Sun a nuclear furnace doesn't help, because no heat source (nuclear or otherwise) creates containment in free space.

There is really only one possibility here, that this is (somehow) a manifestation of EM forces. But what kind of forces could contain plasma in free space? Put in the simplest of terms, the Sun is obviously a bunch of plasma that is attracted to itself -- far more so than gravity can explain -- and there is a drop-off point, which defies the inverse square law of gravity. So what is the attractive force?

Since the hydrogen and helium in the Sun do not have strong magnetic dipoles, we can rule out magnetostatics. In other words, it isn't like a bunch of iron filings clumped together because of magnetic polarization frozen into the solids -- it's plasma, so nothing is frozen in.

This leaves electrostatics as the attractive force. In other words, a charge separation has occurred, and the opposite charges are attracted to each other by the electric force.

Yet now our intuitions are complaining -- how can a charge separation be preserved in the near-perfect conductivity of extremely hot plasma?

There is only one answer to that question -- the only force that can compete with the electric force in free space is magnetic pressure. So how does that work?

We're all familiar with Ampere's Law: an electric current produces a magnetic field around it. At relativistic speeds, the magnetic force becomes as powerful as the electric force, and can influence the current. If it's current flowing through a wire, we won't see much difference, but if the "current" is charged particles shooting through space, the magnetic field exerts back-pressure on the charged particles, consolidating them in what is known as the magnetic pinch effect.

The corollary to the magnetic pinch effect is what we might call the "magnetic push effect." If like charges are consolidated by their superimposed magnetic fields, then opposite charges are separated. Positive charges generate fields by the right-hand rule, where the fingers represent the force on a magnetized particle with the thumb pointing in the direction of the charge stream. Negative charges generate left-hand fields. Thus the fields generated by positive and negative charges moving in the same direction oppose each other. And this, of course, generates magnetic pressure between them -- just like the opposing magnetic fields that drive electric motors. The result is a charge-separated plasma jet. In spite of the enormous electric force between the opposite charges, and without anything else to keep them separate, positive and negative charges form a "twisted pair" of charge streams known as a Birkeland current (in its generalized form). The discovery of the principles controlling plasma jets in space made it possible to understand how CMEs could stay organized through 93 million miles of space and slam into the Earth with full force. (It also sparked the imaginations of science fiction writers who were quick to equip all of their superheroes with plasma guns.) Hence persistent charge separations are possible, even in the presence of near-perfect conductivity, if the charges are moving at relativistic speeds, and are therefore generating opposing magnetic fields.

If this much is true about linear plasma jets, then it is also true about circular jets. In other words, if we could get plasma spinning around in a circle fast enough, the magnetic forces would separate the charges into two distinct streams, one positive and the other negative, and where the electric force would keep them organized, while the magnetic force would keep them separate.

Here it is useful to think of these circular plasma jets as a sort of open-air tokamak. The first difference is that the magnetic fields are not artificially applied from the outside to create the plasma confinement, but rather, are simple artifacts of the speed of the plasma jets themselves. The other difference is that for the purposes of understanding the Sun, it isn't a tokamak generating so much confinement that nuclear fusion is occurring. At the speeds in question (~3 km/s), the electric force is still far more powerful than the magnetic force, and the plasma isn't going to be pinched down to a singularity. But we're not trying to explain the Sun as an infinitesimal twisted pair of circular jets -- we're trying to understand some plasma confinement well beyond the capabilities of gravity. So it's not an all-or-nothing issue, wherein either you have enough confinement for nuclear fusion, or you don't have anything worth mentioning. Rather, 3 km/s plasma jets very definitely generate powerful magnetic fields. (The magnetic fields in electric motors come from electrons moving at roughly 3 x 10^-7 m/s, which is 10 orders of magnitude slower than plasma rotating at 3 x 10^3 m/s in the Sun.) So yes, there will be powerful magnetic fields -- not more powerful than the electric fields, but sufficient to do some magnetic pinching and pushing, and that's all we need to account for some plasma confinement in the Sun, beyond what can be explained by gravity.

To build a model out of these principles, we will start with the core of the Sun. It is known that the core rotates as a solid body, at a faster revolution rate than the overlying layers. In other words, its angular velocity might be the same as the radiative and convective zones, but at a smaller radius it makes more revolutions in the same period. Nominally, we'll say that the angular velocity in the core is 3 km/s. At such speeds, magnetic fields 10 orders of magnitude greater than those in electric motors will generate a magnetic pinch effect that will accomplish some consolidation of like charges, and separation of opposite charges. Just guessing, let's say that the core is positively charged.

This means that outside of the core, there will be a negatively charged double-layer. This double-layer will be attracted to the core by the electric force, but repelled from it by the magnetic force. This layer would be the radiative zone.

Outside of the negative layer, we will then expect there to be yet another oppositely charged layer, this time positive. It will likewise be attracted to the negative layer by the electric force, but repelled from it by the magnetic force, and also repelled by the underlying positive charges in the core. (After the initial charge separation between the core and the radiative zone, it would actually be possible for an infinite number of alternating layers to develop, though in a spherical configuration, the charge densities will diminish with distance from the center. And the successive layers need not have their own charge separation mechanisms. They will form simply by attraction to opposite charges and repulsion from like charges.) The outer positive layer we will presume to be the so-called convective zone.

So we have 3 basic layers: the positively charged core, the negatively charged radiative zone, and the positively charged convective zone. The angular velocities in the core generate magnetic fields that accomplish the primary like-charge consolidation and opposite-charge separation, establishing the radiative zone as a negative double-layer, which goes on to support the convective zone as a positive double-layer around the outside. We will then expect the chromosphere to be yet another charged double-layer, this time negative. But with the extreme heat being released by the photosphere, the density of the chromosphere is extremely slight, and this is the last organized layer.

In this fashion, it becomes possible for a ball of plasma at extreme temperatures to stick to itself in free space. And while this model is extremely rough-cut, it does directly address the issue of non-gravitational density in the Sun, which to my (extremely limited) knowledge has not been resolved by any other model.

Note that this model, as presented so far, does not identify the energy source(s) in the Sun, nor does it speak to the actual complexity of behaviors in the photosphere (granules, spicules, sunspots, prominences, etc.). I "think" that the model can venture well into such territory, and I'll discuss the finer-grain photospheric details on demand. But first, I'd like to get feedback on the central assertions of this model. Does this, in fact, establish a plausible mechanism for spherical plasma confinement in free space? Is it, in fact, the only possible mechanism? Or is there another way of solving this problem?

Post by nick c » Mon Jan 23, 2012 4:18 pm

Hi Charles,

the density of a gas in space should fall off with the square of the distance from the center of gravity

Here in lies the problem, gas laws do not apply, because the Sun is mostly, if not all plasma. Plasma's are not bound by ideal gas laws, as Thornhill has pointed out on numerous occasions.

Post by CharlesChandler » Mon Jan 23, 2012 8:13 pm

Hey Nick,

A better way of putting it would be to say that plasmas are very definitely bound by the ideal gas laws, as these come straight from the inertial forces exerted by particles in motion, and plasmas are particles in motion. Despite their extreme heat, plasmas have extremely low viscosities, because electrostatic repulsion between like-charged atomic nuclei prevents the collisions that instantiate friction. So plasma is as ideal of a gas as you're ever going to get.

But whether particles are bouncing off of each other because of direct contact (in gases) or because of electrostatic repulsion (in plasmas), all collections of matter have hydrostatic pressure, and all fluids (such as plasmas) exhibit hydrodynamic behaviors when flowing in response to pressure gradients. All of these factors have to be taken into account to fully understand the behaviors of plasmas. It's just that things get a tad more interesting if charges have been separated, where the Newtonian forces might become slight compared to the EM forces at play. I think that everybody agrees on that much.

The question is: what are the EM forces at play? You can't just say that plasmas do weird things in the laboratory, and the Sun is weird by Newtonian standards, therefore the Sun is plasma, and call that a complete explanation.

We need to ratchet up the specificity of the contentions. I think that these are solvable problems. But we need to be as critical of ourselves as we are of others.

Post by CharlesChandler » Tue Jan 24, 2012 12:53 am

BTW, in case anybody is seriously considering the properties of the proposed model, I wanted to clarify the whole "tokamak" thing. If we take the concept of a tokamak and start imagining one floating around in free space, we're thinking of a positively charged plasma stream in a toroidal form. Then I'm saying that there is a negative double-layer around that. So we might think of the stuff inside the tokamak as being pure atomic nuclei, while the stuff in the negative double-layer would be pure electrons. But that wouldn't be correct -- helioseismic data would show quite a distinct boundary between the atomic nuclei inside the tokamak and the pure electrons outside of it, and such a distinct boundary doesn't exist. So what I'm saying is that under the surrounding pressure, the distribution of atomic nuclei is more or less the same throughout, with a noticeable but not dramatic dip in density through the radiative zone. The main proposed effect of the tokamak is just that the Sun's electron cloud is not evenly distributed -- there are more electrons in the radiative zone than in the core and in the convective zone. In other words, it's not pure anything. The core and the convective zone are predominantly positive, while the radiative zone is predominantly negative, and this is because of the magnetic fields generated by the angular velocities that accomplish partial charge separation. And it is because of the main body of negative charge in the radiative zone that we get a convective zone that clings to the outside of the Sun, which cannot be explained any other way to my (limited) knowledge.

Oh, hey Dave! I wrote the above before I saw your post. The electron cloud thing "might" address the issue that you identified. Thinking in terms of an even distribution of atomic nuclei, but with a concentration of electrons in the radiative zone, the electric force exerted all the way out at the edge of the photosphere "might be" nearly spherical, even if the positive charge density in the core is toroidal. In other words, if we have a positively charged doughnut that is 20% of the overall radius, what is the form of the space charge in the negative double-layer? It isn't going to be toroidal, but rather, somewhat ellipsoidal. The positive double-layer outside of that will be ellipsoidal, but less so. How much less so? The last time I checked, scientists consider the Sun's oblateness to be consistent simply with its angular velocity. So if I'm right and they're right, electrostatic repulsion in the charged layers is distributing the charges, which smooths the toroid out into a sphere at its full radius.

If you're going with millions of self-reinforcing filaments, then you have to explain what motivates them. If it's charge separations, then what is continually creating these charge separations?

I'm thinking of granules primarily as thermal bubbles, but there has to be more to it than just convection. While the rate at which granules rise, given their temperature, can be attributed to buoyancy, the rate at which they expand outward (2 km/s), and the rate at which the cooled plasma "falls" back into the Sun (7 km/s), is not convective. 2+ km/s is supersonic in the photosphere, and in no sense do the principles of convection explain supersonic speeds. Furthermore, convection isn't going to pull anything back into the Sun, given the steep pressure gradient in the photosphere. For the answer to be convection, the question has to assume that the pressure gradient is caused strictly by gravity, which is false, and which tosses the answer along with it. Clearly EM forces are at work. So I'm thinking that the positively charged thermal bubbles reach the edge of the photosphere, where they cool enough to be able to hold onto electrons for a little while. But the neutralization of charge re-heats the plasma, and the plasma can't hold onto the electrons, so it regains its positive charge. It is then sucked back down by the electrostatic attraction to the underlying negative charge in the radiative zone. This explains why the brightest parts of the granules are on the edges, where the "cooler" plasma has a negative buoyancy, and is therefore falling back into the Sun.?

Wikipedia wrote:

Solar faculae are bright spots that form in the canyons between solar granules, short-lived convection cells several thousand kilometers across that constantly form and dissipate over timescales of several minutes. Faculae are produced by concentrations of magnetic field lines.

The magnetic field lines are there, but what is the magnetomotive force? In plasma, only moving electric charges can generate powerful magnetic fields, so this is actually just confirming that the plasma accelerates to 7 km/s as it dives back into the brick wall pressure gradient, which can only be because of the electric force.

Post by CharlesChandler » Tue Jan 24, 2012 8:46 pm

mharratsc wrote:Addressing spherical symmetry, here is an animation of a plasma pinch occuring inside Lerner's dense plasma focus:

I think you're aware that proponents of the Electric Universe/Electric Sun model feel that all stars are powered by energy received from their galactic circuits, right? Lot's of power there for the taking!

Here's a better video (with sound to explain what's going on): http://focusfusion.org/index.php/site/a ... animation/

Yet this is just another example of some of the fancy things that "might" happen (the video is an animation, and anything is possible in an animation) when working with high voltages between solid electrodes. Getting the same thing to happen, when the electrodes are clumps of plasma, is a little bit harder. The electrostatic repulsion between like charges at the electrodes is, by definition, more powerful than the electrostatic attraction between the electrodes, because of the distance factor. :? In a solid electrode, the crystal lattice of the solid holds the electrode together, but in plasma, with only gravity holding it together, the repulsion has a tendency of dispersing the plasma. This is something that I had to learn in order to understand thunderstorm electrification. If you look at the principles of EM as a grab-bag of diverse properties, you can make anything do anything. But some of those things aren't actually going to work if you take all of the factors into account. I went down many a blind alley, seeing a behavior of thunderstorms and grabbing the EM property that "could" do that, when really it couldn't under the circumstances. So you have to look at all of the factors. With respect to the "galactic circuit", I'd like to know how that much electricity flows, from that distance away, toward an electrode made of plasma, that somehow remains an electrode with a net charge, without electrostatic repulsion blowing it apart.

Ironically, if you actually looked at my model, you'd realize that I'm actually solving your biggest problem. I think that I would still disagree with you, that the Sun's primary energy source is external. But if it is, and if it is electromagnetic, you have to explain what overcomes electrostatic repulsion to maintain the net charge, thereby enabling the voltage and thus the current. My model can explain that -- yours cannot.

mjv1121 wrote: The concept that some parts of a star may be positive and some negative is as ridiculous as the Birkeland current power transfer model - there really is no hope for this nonsense.

Would it be superstitious to think that some parts of a thunderstorm are positive and some negative, and that the voltage can be so high that it causes sparks several kilometers long?

Nevertheless, I agree with you that the Birkeland current power transfer model, black holes, and astrology are all flawed regimes. (Ask me about black holes if you care to consider another implication of the model I'm using. I think that these can be explained with classical physics, without having to warp the fabric of space and time, with EM principles, but without Birkeland currents.)

mjv1121 wrote: Talking of nonsense, tokamaks have been mentioned, which is such a huge gaff that I am unable any longer to find funny. The idea is presumably to give credibility to the theory by referencing the presently favoured (funded) fusion power hope. The tokamak, along with any magnetic confinement device, is a fool's errand - emphasis on the FOOL.

I agree that tokamaks are hopelessly flawed. Scientists should be able to take a step back, and realize that they will never get more power out of a rig like that than they're putting into it. But the Russians invented it, the U.S. didn't want for there to be so much as the perception that it was falling behind, and now everybody has to have one. Who knows how much money has been wasted. Anyway, you might be right, that using an analogy from a failed research paradigm might be a poor choice. But that doesn't invalidate Ampere's Law, which is the actual foundation for my model.

mjv1121 wrote: I ask again: By what method was the Sun's density gradient derived?

Helioseismology. The one useful thing about CMEs is that they create shock waves that travel through the Sun, and we can measure how long it takes for the waves to bounce back and forth inside the Sun. From this we can calculate the density, the same way we have learned about the innards of the Earth from the shock waves created by earthquakes. Note that with respect to both the Earth and the Sun, this is the only information that we have about the interior of the orbs. Estimates of the temperatures inside the Sun are purely conjectural, and highly contentious, while the density gradient is based on actual data.

Post by CharlesChandler » Wed Jan 25, 2012 7:45 am

mjv1121 wrote: The entire concept of negative and positive is superstition driven - there is no such thing at any level of physical reality.

This is overflow from your "What is electricity" thread. You should refrain from cross-posting, as spreading the discussion across many different threads makes it difficult to follow. In all due respect, I'll answer the question, but if you want to continue the debate, you should do so in the other thread.

Positive and negative are for electricity what north and south are for magnetism -- they're arbitrary labels for the sources of forces that can be attractive or repulsive. What is the mechanism that gives rise to such forces? For my purposes, that doesn't matter. If you come up with a lower-level concept, that isn't going to change the macroscopic effects. So for my purposes, the difference would be terminological at best.

mjv1121 wrote: So, exactly how is a density gradient calculated from such a method?

Actually, that's an interesting question. All other factors being the same, the speed of sound varies slightly as a direct function of density, but more substantially with the rigidity of the matter. Hence materials that have the same mass might transmit sound waves at different rates, depending on their crystal lattice. In plasma it shouldn't matter much, but the core of the Sun is compressed to a density far greater than normal solids here on Earth, which makes the core act like a rigid solid in how it transmits sound waves.

But it's nowhere near that simple. Waves propagating across the surface of the Sun increase in speed as they go, completely defying Newtonian mechanics. In my mind, this can only mean that the surface has a net charge, as the motion of one particle begins to accelerate the next particle even before they collide, by electrostatic repulsion. (This also supports the contention that the net charge in the photosphere is positive, not negative, as negative ions in a highly conductive medium wouldn't do this -- they would just lose their excess electrons, with little effect on the inertia of the nuclei.)

Regardless, the fact that the surface supports transverse waves means that there is a sharp change in density, and this is not predicted by the laws of gravity and hydrostatics.