"Let me look at you with my own eyes"

Discuss how polywell fusion works; share theoretical questions and answers.

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bennmann
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"Let me look at you with my own eyes"

Post by bennmann »

In WB8.1, presuming pB11 reaction, would the plasma be safe to look at directly?

Cause that would be wicked sweet. I presume it would be BRIGHT, sure, but how bright I wonder? Could you marvel at the fusion as you watched it with your own eyes?

Braum is really the only thing stopping this, perhaps. But xrays should be minimal too? I mean most of the reaction is going into the alphas, sooooo would it be possible, even with those xrays?

kunkmiester
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Post by kunkmiester »

I had the thought that a power plant aesthetic might be to provide windows of some sort so that the glow is used to illuminate the outside of the plant. The big deals are leaded glass for the windows, and the seal for the vacuum chamber. I'd imagine it's too bright to look at directly, but such an indirect system would be fine. The emission spectrum for hydrogen and boron are also close--you'd have a blue or purple light, or thereabouts.
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D Tibbets
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Post by D Tibbets »

Actually, in an ideal machine you would see nothing. The visible emissions occur from recombination (neutralization) of various ions. This means only unwanted waste losses would show up as visible glows. The ions and electrons themselves would have so much energy that any emissions due to acceleration (like bremsstrulung) or collisions would be in the far ultraviolet and x-ray ranges. And of course fusion produced ions would be even higher energy.

Of course when the X-rays or energertic particles hit your retina, secondary reactions may stimulate the nerves to fire and give an apparent flash of light. This happens with cosmic rays.
So yes, you could see some light 'inside' the reactor, but only from waste reactions or from radiation hitting the retina.

Keep in mind that exothermic chemical reactions produce a fraction of a electron volt of energy and this can give a black body emmision of visible light. A fully ionized hydrogn atom might have an energy of a little over 10 electron volts and it would glow in the UV range. The ions in a fusion plasma would be at ~ 5,000 to 500,000 thousand eV.

The pictures you may have seen of a glow in a Tokamac represents border regions or other defects where recombination is producing a visible glow. This represents fluorescence where electrons are captured by an ion ( this radiation is probably in the UV range). Subsequent drops of the electrons to lower/ less energetic orbits emits the visible light at specific wavelengths.
The glow in a glow discharge fusor (or fluorescent lamp) or like that seen in the picture of WB8 on the EMC2 website is due to this. It represents a subset of the atoms that are defiantly not contributing to the fusion process (except as a potential target for a fast moving ion).

Dan Tibbets
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bennmann
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Post by bennmann »

Cool Dan.

D Tibbets
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Post by D Tibbets »

I might add, that the x-rays produced in a fusor or other device that operates in the milliamp range could cause significant radiation damage if the voltage is high enough and the exposure is long enough. X-ray imaging machines operate in similar to mildly higher current ranges.
The x-rays from a multiple amp machine could very quickly become dangerous without some thick lead shielding (or other thicker metals) and/or a lot of distance. A machine that is producing up to several Megawatts (at perhaps 100,000 volts and 200 amps equivalent) bremsstrung x-rays would kill an unprotected individual with exposures as short as a few seconds(?).
And this disregards other radiation like neutrons or gamma rays that may be present in large quantities, depending on the fuel. Best to stay away, unless protected by a thick shielding wall.

Dan Tibbets
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WizWom
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Post by WizWom »

http://emc2fusion.org/RsltsNFnlConclFmI ... 120602.pdf The Literature talks about "Paschen arc breakdown" in the plasma.
This is the same effect seen in plasma toys, random bright arcs though the plasma from one conducting surface to another.
There will also be the Bremsstrahlung radiation, which has a black-body curve, so once it gets hot enough, the plasma will glow white-hot. This would go away in a perfect machine where the electrons magically get into the center.
The energy in a p-B11 machine should be all released as kinetic energy of the He ions. These would have an average around 3MeV energy, and they would, I expect, impact the wall of the chamber, as they will be turned less strongly by the magnetic fields. This is good, because that way their energy can be harnessed through standard thermal processes. [/url]
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D Tibbets
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Post by D Tibbets »

WizWom wrote:http://emc2fusion.org/RsltsNFnlConclFmI ... 120602.pdf The Literature talks about "Paschen arc breakdown" in the plasma.
This is the same effect seen in plasma toys, random bright arcs though the plasma from one conducting surface to another.
There will also be the Bremsstrahlung radiation, which has a black-body curve, so once it gets hot enough, the plasma will glow white-hot. This would go away in a perfect machine where the electrons magically get into the center.
The energy in a p-B11 machine should be all released as kinetic energy of the He ions. These would have an average around 3MeV energy, and they would, I expect, impact the wall of the chamber, as they will be turned less strongly by the magnetic fields. This is good, because that way their energy can be harnessed through standard thermal processes. [/url]
X-rays from bremsstrunlung are not white hot- they are invisible to the eye. And, I don't believe it is blackbody radiation. Black body radiation is a light emission based on the temperature of an object or gas, etc- it is what is seen with an incandescent light bulb or a hot piece of iron.
Bremsstrulung is from acceleration of electrons around an ion, etc. I believe x-rays are produced mostly in this way or by impacting high energy electrons on an appropriate target (how x-ray tubes work).

For the alpha particles from a P-B11 reaction, the alphas escape through the cusps in the magnetic fields (holes in the wiffleball). They escape because they are traveling too fast for the electrostatic potential well to stop them. This matches well what Bussard said about the wiffleball (magnetic) traping factor of ~ 1000, and Nebel's statement that alphas will circulate ~ 1000 times before they find and exit through a cusp. Less efficient magnetic Mirror confinement (like in a Penning trap) might contain for ~ 50-60 orbits, and simple cusp confinement for only a few orbits (I assume this was the basis for Carlson's mention that he would expect the alphas to only orbit ~ 1 time before exiting). This illustrates the significance of the wiffleball, and the subsequent electrostatic confinement that keeps ions (if they are not moving too fast)traped for even longer times.

Dan Tibbets
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WizWom
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Post by WizWom »

From what I understand, the ions and electrons must have average energies no higher than the protection afforded by the magnetic grid, this is the "beta-one" level in the literature. Less is less efficient, that is, you'd be using more energy for the protecting magnetic grid than needed; more energy means the ions and electrons will have enough energy to hit the surfaces of the whiffle ball grid.

In any thermal system, the energy is a distribution with a peak, the peak is the "temperature." In an accelerated system (like the electrons and ions in a polywell) you have control of the initial temperature, but the system will determine the average temperature (which is what the WB-6 machine showed).

In the case of a Polywell, the electrons (hopefully) won't come anywhere near the ions because of the magrid; instead, they will exhibit bremsstrahlung or synchrotron radiation from the grid turning them. In fact, now that I'm thinking about it, I'm pretty sure the electrons should never come near the ions.
[better correct this. Just listened to Dr. Bussard's explanation again.]
So, the Ions and the electrons are in the same volume, and the bremsstrahlung radiation is because they are both contained by the magnetic fields. They are maintained as ions by the thermal environment.

I understood bremsstrahlung energy as a curve with a sharp cutoff, not a single energy level. The curve is dependent on the electron and ion energies, and the randomness is from the initial angle and distance that the electrons and ions have.

Now, I'm not sure whether the light that WB-6 gave off was from Bremsstrahlung, synchrotron or cyclotron radiation. Honestly, I don't think I have the background yet to tell the difference. It might be Bremsstrahlung in the center, and cyclotron outside.

Seeing as WB-6 was designed with a 12kV potential, I'm sure that's not high enough speed for synchrotron radiation. So, I'd put my money on cyclotron radiation, emitted by the electrons and ions moving in curved paths along the magnetic fields generated by the whiffle ball.
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