Plasma Stars

[paladin17]

That leads to the question whether a CFDL between the photosphere and the corona can sustain this field given the difference in physical properties of the two populations. I'll have to think about that. Has anyone modelled it?

Generally, double layers are maintained by the balance of electrostatic and inertial forces, as determined by Poisson (with n_e != n_i) and momentum equations.
One mechanism that might lead to the formation of this particular layer is a simple ambipolar diffusion. We know for sure that there should be a radially outward electric field simply because of electron-proton mass difference (assuming the same temperature), and this field might as well be confined to a double layer. Bob Johnson (it is actually his idea that I'm repeating here) assumed that this double layer is located in the transition region.

If I remember right, the suprathermal to thermal electron ratio in the solar wind is about 1:10, so could we just put the thermal electrons and the ions escape down to thermal velocity followed by the field acceleration. In that case we should be able to measure the field accelerating the ions (or at least infer it from particle densities) if we get close enough to the Sun, if indeed that is what is happening.

There is such a possibility, certainly. It has been shown that the proportion of runaway electrons directly depends on the ratio of the [parallel electric] field and Dreicer's field.
In general, there has been some new research on the subject as well.

[jacmac]

paladin17

One mechanism that might lead to the formation of this particular layer is a simple ambipolar diffusion. We know for sure that there should be a radially outward electric field simply because of electron-proton mass difference (assuming the same temperature), and this field might as well be confined to a double layer. Bob Johnson (it is actually his idea that I'm repeating here) assumed that this double layer is located in the transition region.

I think I remember Bob Johnson's DL there was a current free DL ?
For my plasma CELL idea to even come close I would be looking for a DL with some current.
My candidate, for current, is the 1...3 million or so spicules from the chromosphere up into the Corona.
I believe the spicules are in the transition zone; at the top of, or just above, the chromosphere.

[Higgsy]

That leads to the question whether a CFDL between the photosphere and the corona can sustain this field given the difference in physical properties of the two populations. I'll have to think about that. Has anyone modelled it?

Generally, double layers are maintained by the balance of electrostatic and inertial forces, as determined by Poisson (with n_e != n_i) and momentum equations.
One mechanism that might lead to the formation of this particular layer is a simple ambipolar diffusion. We know for sure that there should be a radially outward electric field simply because of electron-proton mass difference (assuming the same temperature), and this field might as well be confined to a double layer. Bob Johnson (it is actually his idea that I'm repeating here) assumed that this double layer is located in the transition region.

I understand all of that and was there already. My question was whether anyone had modelled the DL starting with expected physical conditions on either side and calculating the charge separation and other parameters of the resulting DL to see whether a it produces a field which exceeds the Dreicer limit.

In general, there has been some new research on the subject as well.

Thank you. I'll look at that later.

[Cargo]

Well if we can't model the starting physical conditions of black holes and big bangs and neutron stars and icy comets, who cares. I can only assume your deft cleft is still looking for some slight way to 'debunk' plasma in space. If only the Higgs could refer to some law of reality for guidance.

[paladin17]

I understand all of that and was there already. My question was whether anyone had modelled the DL starting with expected physical conditions on either side and calculating the charge separation and other parameters of the resulting DL to see whether a it produces a field which exceeds the Dreicer limit.

If you're talking about numerical estimates, I haven't seen such.

[paladin17]

Let's make some estimates.
Based on this we may assume that the charge of the Sun due to ambipolar diffusion is some tens of coulombs. Therefore, if we suppose that there is a spherical double layer with this charge and of the thickness d, we get V = kQd/R^2, where k is the constant (1/4*Pi etc.), V is the total voltage between the two layers, and R is the distance of the layer from the Sun's center (roughly equal to the radius of the Sun itself) - we also assume d << R, obviously.
Therefore, V/d = kQ/R^2, which gives us the field of only about 10^(-6) V/m in the double layer. I have no problems believing such a field may exist, though whether it would be enough to produce the runaway electron population is pretty doubtful. I'd have to find the exact expression of the needed ratio. It is also possible that in case of the field being confined to a thin DL the solar charge would need to be bigger than the estimate given in the cited paper, which would make the field stronger.

[JHL]

Well if we can't model the starting physical conditions of black holes and big bangs and neutron stars and icy comets, who cares.

I believe the Acceptable Science also allows for the construction of Eventual Maths for any conjecture, from which when they can be arranged to work, we have not just Circular Proof but a logical time machine thereof.

It's the scientific mashup of post hoc and QED.

Seriously, this doesn't make it not so - maybe everything arrived from a great self-spawning will to produce it from that one minuscule, magical point in space that had previously violated every construct known but doesn't anymore - but it does tend to mitigate against the almighty hubris that comes freighted with the standard model.

Watched any recent cosmological or astrophysical documentaries per the standard universe? The self-satisfaction and myopia are at record levels, heightened by the dramatic lighting, the amusing over-acting, and the dramatic music. That's what a friend once called the thud of a lie. Every time I watched an EU doc, on the other hand, it had the ring of understated, intuitive truth, even as the theory it is.

[jacmac]

Steady Electron Runaway Model SERM: Astrophysical Alternative for the Maxwellian Assumption

A Steady Electron Runaway Model (SERM) is formulated describing plasmas in the astrophysical "condition" having finite (rather than infinitesimal) Knudsen number, ${{\mathbb{K}}}_{\mathrm{Pe}}$, suggesting an omnipresent leptokurtic, nonthermal, and heat-conducting electron velocity distribution function (eVDF) as the replacement for the Maxwellian ansatz typically made.

Thank you Mr. paladin17, but I think I'll leave that one for you and Higgsy to decipher.
The other paper I find more accessible and interesting.
https://www.aanda.org/articles/aa/full/ ... h2649.html
I need to read it again and comment later.

[Higgsy]

Let's make some estimates.
Based on this we may assume that the charge of the Sun due to ambipolar diffusion is some tens of coulombs. Therefore, if we suppose that there is a spherical double layer with this charge and of the thickness d, we get V = kQd/R^2, where k is the constant (1/4*Pi etc.), V is the total voltage between the two layers, and R is the distance of the layer from the Sun's center (roughly equal to the radius of the Sun itself) - we also assume d << R, obviously.
Therefore, V/d = kQ/R^2, which gives us the field of only about 10^(-6) V/m in the double layer. I have no problems believing such a field may exist, though whether it would be enough to produce the runaway electron population is pretty doubtful. I'd have to find the exact expression of the needed ratio. It is also possible that in case of the field being confined to a thin DL the solar charge would need to be bigger than the estimate given in the cited paper, which would make the field stronger.

I also have no trouble believing that a field of that magnitude might exist, but it's too low by four orders of magnitude to reach the Dreicer field in the corona (which I make ~15mV/m assuming n=10^16 m^-3, T=2 x 10^6K, and lnΛ=10).

I want to think about differential diffusion of the two electron populations across the transition zone which have a different temperature by a factor of 10^3 at least (assuming plasma is collisional on both sides, the ion and electron temperatures are in equilibrium (doubtful?) and yadda, yadda), which would set up a double layer with a potential drop of some 10s of volts (see here and here), φ = kT/2e, say ~86V based on assumptions above. If the DL thickness is less than about 5km the field will exceed the Dreicer limit. 100 x Debye lengths in the corona is about 0.1m so there is a lot of scope for a field much higher than the Dreicer limit in the corona, even with this back of a postage stamp estimate.

The problem is the location of this double layer as the DL potential goes with temperature while the Dreicer field goes with the inverse of temperature and goes with number density, so if we locate the DL in the transition zone, it becomes much more difficult to explain suprathermal electrons by a DL. It works better if we take the coronal electron temperature to be higher than the ion temperature.

[Cargo]

What's the Debeye diameter of the gravity-fusion-core for the standard Higgs/Nasa model? Can that be also be converted Plank units?

[paladin17]

I also have no trouble believing that a field of that magnitude might exist, but it's too low by four orders of magnitude to reach the Dreicer field in the corona (which I make ~15mV/m assuming n=10^16 m^-3, T=2 x 10^6K, and lnΛ=10).

I want to think about differential diffusion of the two electron populations across the transition zone which have a different temperature by a factor of 10^3 at least (assuming plasma is collisional on both sides, the ion and electron temperatures are in equilibrium (doubtful?) and yadda, yadda), which would set up a double layer with a potential drop of some 10s of volts (see here and here), φ = kT/2e, say ~86V based on assumptions above. If the DL thickness is less than about 5km the field will exceed the Dreicer limit. 100 x Debye lengths in the corona is about 0.1m so there is a lot of scope for a field much higher than the Dreicer limit in the corona, even with this back of a postage stamp estimate.

The problem is the location of this double layer as the DL potential goes with temperature while the Dreicer field goes with the inverse of temperature and goes with number density, so if we locate the DL in the transition zone, it becomes much more difficult to explain suprathermal electrons by a DL. It works better if we take the coronal electron temperature to be higher than the ion temperature.

If we'd look at the runaway critical velocity equation in terms of the corresponding kinetic energy, we'd arrive at K (in eV) ~ [10^(-17)*n*ln Λ]/E, where E is the electric field.
So if we assume for the outer chromosphere boundary n ~ 10^10 and my E ~ 10^(-6), K would be of the order of 1, which is, as far as I can tell, about what is needed (since temperature itself is about 0.3 eV).