Focus Fusion news story

Point out news stories, on the net or in mainstream media, related to polywell fusion.

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Betruger
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Post by Betruger »

Mike_P wrote:So have I, but I don't believe this kind of behavior is endemic of any one ethnicity. Some people just like to start an argument for the sake of entertainment.
The method to that end is too consistent with the population sample I've known first hand to be a coincidence. Regardless, I'd say he's no troll, and the psych/cultural tangent is too off topic.

On topic, wouldn't it be better to wait for EMC2 to reach the end of their current R&D cycle? IE "WB8.x". Or till whatever point we can see WB8 is either running out of $$, or is turning into another ITER (FOIA time), or hopefully till we see sure enough hints of success. To wait for that time before any serious lobbying. We probably shouldn't count on any second chances, so timing must be optimal.
You can do anything you want with laws except make Americans obey them. | What I want to do is to look up S. . . . I call him the Schadenfreudean Man.

Mike_P
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Post by Mike_P »

I can see your point if I were to believe that "only" the folks at EMC2 are capable of research. Unfortunately taking the position that we need "experts" to tell us if something is worth pursuing is the very thing that got us into the position we are in with the Tokamak project. IMHO there is no one in Congress that will step out and propose funding for alternate fusion research because of this very attitude that "experts" are needed to lead along the right path. History is replete with examples of individuals who went against the experts and succeeded.

At this point in time there has been enough demonstrable evidence to indicate that alternative funding needs to take place on a multitude of projects. The lobbying group is meant to educate and move public opinion towards these methods rather than building large windmills all over the country. (On a personal note I live near one of the major windmill farms in SoCal and its an ugly thing to see.)

Betruger
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Post by Betruger »

I agree. I thought you meant lobbying specifically for Polywell right now. With all the money being thrown around, there definitely should be more for these alternatives.
You can do anything you want with laws except make Americans obey them. | What I want to do is to look up S. . . . I call him the Schadenfreudean Man.

93143
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Joined: Fri Oct 19, 2007 7:51 pm

Re: Ummmm ...

Post by 93143 »

Joseph Chikva wrote:As by my primitive thinking if people speak "virtual cathode" and "potential well attracting ions" this means, my little friend, "periodically oscillated over center ions" or POPS.
POPS stands for "Periodically Oscillating Plasma Sphere" and describes a bulk resonance condition. An electrostatic fusion device with spherical ion focus does not naturally develop this behaviour; it must be driven properly.

Robthebob
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Post by Robthebob »

I went and looked around, and for POPS to happen, you need to have a spherical harmonic oscillator potential (as stated by the POPS paper done by Park, Nebel, et all).

Potential energy of spherical harmonic oscillator:
V=(1/2)(kr^2)

Potential energy of centripetal force:
V~ -1/r

But I think you can drive polywell's potential well to be spherical harmonic oscillator potential, but it doesnt have to have that potential energy. On another note, what kind of potential does polywell have?

Oh wait tho, Joe, you're always right. What am I thinking, I must be wrong.

WHOLE FORUM GETTING TROLLED BY JOE!
Throwing my life away for this whole Fusion mess.

Mike_P
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Location: Thousand Oaks, CA

Post by Mike_P »

If I believe Wikipedia then each reaction yields:
p + 11B → 3 4He + 8.7 MeV

Can I assume that 8.7 MeV is enough kinetic energy to pop over the potential wall and make it out to the power conversion plate? If so, then why would we want to oscillate the power to the magnets? I would think that a good vacuum pump would clear the chamber of unwanted helium.

hanelyp
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Post by hanelyp »

Mike_P wrote:If I believe Wikipedia then each reaction yields:
p + 11B → 3 4He + 8.7 MeV

Can I assume that 8.7 MeV is enough kinetic energy to pop over the potential wall and make it out to the power conversion plate? If so, then why would we want to oscillate the power to the magnets? I would think that a good vacuum pump would clear the chamber of unwanted helium.
The depth of the potential well is in the neighborhood of 100keV. So even divided unevenly between 3 alphas with 2 protons each, 8.7MeV is easily enough to escape the potential well.

The purpose of POPS is that it gives you cyclical high fuel density. Fusion rate scales with density squared, so alternating high and low densities in the core gives a higher reaction rate than a static medium density.

Yes, you'll want a good set of vacuum pumps to keep the high vacuum in the chamber.

Joseph Chikva
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Re: Ummmm ...

Post by Joseph Chikva »

93143 wrote:
Joseph Chikva wrote:As by my primitive thinking if people speak "virtual cathode" and "potential well attracting ions" this means, my little friend, "periodically oscillated over center ions" or POPS.
POPS stands for "Periodically Oscillating Plasma Sphere" and describes a bulk resonance condition. An electrostatic fusion device with spherical ion focus does not naturally develop this behaviour; it must be driven properly.
Thanks for an explanation, but how the resonance will be coordinated with the statement that the EMC2 improved electronic guns for the better heating (thermalize) plasma?

93143
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Post by 93143 »

1) POPS is not necessarily directly related to Polywell. It's an earlier project that Nebel and Park worked on, using fusors. It is possible that Polywell, as a concept, is compatible with POPS. It's even possible that they're already using it. But they are not the same thing.

And I must stress that POPS is not the only logical alternative to a uniform thermal plasma - the operating principle of Polywell as originally described corresponds to neither of these concepts.

2) "Heating" doesn't necessarily mean you're dealing with a thermal plasma. You seem very intent on conflating these two things. In the language of electrostatic devices, "hot" can simply mean high-energy.

...

Interestingly, it seems that electron beam injection is an important component of making POPS work:
Park, Nebel, Stange, and Murali (2005) wrote:A requirement for POPS is that the electron injection produces a stable harmonic oscillator potential.

Joseph Chikva
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Post by Joseph Chikva »

93143 wrote:2) "Heating" doesn't necessarily mean you're dealing with a thermal plasma. You seem very intent on conflating these two things. In the language of electrostatic devices, "hot" can simply mean high-energy.
In the all other languages including the language of official documents I hope you know that "heating" means "thermalization". And that was official document on what money was spent: "for better heating".
Recall that all mirror machines were heated (thermalized) with the help of external injection.

And thanks. At least after two your short remarks I understood what they mean saying “POPS”.
As earlier I thought that POPS is a name of Polywell’s desired principle: oscillation of ions around the center.
Now I understood that they want that also whole plasma would oscilate too.

Joseph Chikva
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Post by Joseph Chikva »

Robthebob wrote:I went and looked around, and for POPS to happen, you need to have a spherical harmonic oscillator potential (as stated by the POPS paper done by Park, Nebel, et all).

Potential energy of spherical harmonic oscillator:
V=(1/2)(kr^2)

Potential energy of centripetal force:
V~ -1/r

But I think you can drive polywell's potential well to be spherical harmonic oscillator potential, but it doesnt have to have that potential energy. On another note, what kind of potential does polywell have?

Oh wait tho, Joe, you're always right. What am I thinking, I must be wrong.

WHOLE FORUM GETTING TROLLED BY JOE!
No, I am only asking if there in recovery.com is written "better heating" why energy of harmonic oscillator (1/2)(kr^2) and why not Boltzman's 3/2kT?

93143
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Joined: Fri Oct 19, 2007 7:51 pm

Post by 93143 »

Joseph Chikva wrote:In the all other languages including the language of official documents I hope you know that "heating" means "thermalization".
I may not be a plasma physicist, but I have studied gaskinetic theory as part of my Ph.D. In addition, English is my native language, and my command thereof is equal or superior (so far as I can judge) to that of every other engineer or engineering student whose writing skills I have had the opportunity to assess.* "Heating" and "thermalization" are not the same thing.

Heating means adding kinetic energy without a corresponding net addition of momentum; the usual implication is that the energy is thermally distributed, but in a system not in thermodynamic equilibrium it doesn't have to be. Thermalization, on the other hand, means the relaxation of a particle velocity distribution towards statistical equilibrium, which implies energy exchange between particles but not a global energy increase. Surely you can imagine how a plasma might be locally "hot" in the energetic sense without being "thermal", or vice versa?

Now, Polywell as described owes almost all of its ion "temperature" (local average kinetic energy) over most of the plasma volume to the potential well produced by electron injection. Is it not clear from this that "plasma heating" by electron injection need not necessarily refer to the production or maintenance of a hot thermal plasma?
And thanks. At least after two your short remarks I understood what they mean saying “POPS”.
You're welcome - I'm glad I could help.


* This isn't as grandiose a claim as it sounds; engineers, even native speakers, are notoriously bad at written English...

Joseph Chikva
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Post by Joseph Chikva »

Dear Dr. 93143
This is not language issue but this is an understanding issue
93143 wrote:Heating means adding kinetic energy without a corresponding net addition of momentum;
This is acceleration and not heating as heating is the following: http://en.wikipedia.org/wiki/Heat
Heat is energy transferred from one system to another by thermal interaction.[1][2] In contrast to work, heat is always accompanied by a transfer of entropy. Heat flow is characteristic of macroscopic objects and systems, but its origin and properties can be understood in terms of their microscopic constituents.
93143 wrote:Thermalization, on the other hand, means the relaxation of a particle velocity distribution towards statistical equilibrium, which implies energy exchange between particles but not a global energy increase. Surely you can imagine how a plasma might be locally "hot" in this sense without being "thermal", or vice versa?
http://en.wikipedia.org/wiki/Thermalisation
In physics, thermalisation (in American English thermalization) is the process of particles reaching thermal equilibrium through mutual interaction.
And I do not see difference between "heating" and "thrmalization". Regardless that how bad my English is.
And as you not a plasma physicist I can tell you that in all past designs of magnetic traps (mirror machines) plasma was heated (thermalized) by external injection. And all those had convex fields.

Betruger
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Post by Betruger »

Pretty sure the electron microprobe I've worked on used the same terminology. "Heating" is the word used for its e-guns. This is a european microprobe and is used all across the US/Canada. And many other countries around the world. So the terminology isn't obscure.
You can do anything you want with laws except make Americans obey them. | What I want to do is to look up S. . . . I call him the Schadenfreudean Man.

tomclarke
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Contact:

Post by tomclarke »

Joseph Chikva wrote:Dear Dr. 93143
This is not language issue but this is an understanding issue
93143 wrote:Heating means adding kinetic energy without a corresponding net addition of momentum;
This is acceleration and not heating as heating is the following: http://en.wikipedia.org/wiki/Heat
Heat is energy transferred from one system to another by thermal interaction.[1][2] In contrast to work, heat is always accompanied by a transfer of entropy. Heat flow is characteristic of macroscopic objects and systems, but its origin and properties can be understood in terms of their microscopic constituents.
93143 wrote:Thermalization, on the other hand, means the relaxation of a particle velocity distribution towards statistical equilibrium, which implies energy exchange between particles but not a global energy increase. Surely you can imagine how a plasma might be locally "hot" in this sense without being "thermal", or vice versa?
http://en.wikipedia.org/wiki/Thermalisation
In physics, thermalisation (in American English thermalization) is the process of particles reaching thermal equilibrium through mutual interaction.
And I do not see difference between "heating" and "thrmalization". Regardless that how bad my English is.
And as you not a plasma physicist I can tell you that in all past designs of magnetic traps (mirror machines) plasma was heated (thermalized) by external injection. And all those had convex fields.
Joseph:
thermalisation: moving towards equilibrium KE distibution
heating: increasing average temperature

In non-equilibrium distributions temperature is not well defined, but it is usual to relate average KE of non-equilibrium particles to the temperature that would have that same average KE.

[maybe there is a more precise definition - I'm speaking informally here]

Therefore it is normal to view injecting high KE non-equilibrium particles as heating, even when distribution stays highly non-equilibrium.

But although use of heating in context of non-equilibrium distribution is I agree somewhat ambiguous, there is no way on earth that heating can be the same as thermalisation. One changes temperature, the other does not.

Of course, if you assume the system must reach equilibrium then heating via particles hotter than the plasma will result in subsequent thermalisation.

The argument for polywell is that this thermalisation happens relatively slowly compared with the injection rate, maintaining a non-thermal distribution.

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