Pros and Cons of Fusion Power Generation

[Astronuc]

Is Journal of Fusion Energy a peer-reviewed publication?

It is published by Springer, a reputable publishing house of scientific literature.

It does have an editorial board consisting of various academics. And the principal editor is Stephen O. Dean of Fusion Power Associates, Gaithersburg, MD, USA, which itself has member organizations consisting of universities, public and private research organizations and national labs.

Associate Editors

Igor Anisimov, Taras Shevchenko Kiev University, Ukraine; Niek Lopes Cardozo, FOM Institute for Plasma Physics Rijnhuizen, The Netherlands; Gennadi Dimov, Budker Institute of Nuclear Physics, Novosibirsk, Russia; Lev Golubchikov Kurchatov Institute, Moscow, Russia; Ryosuki Kodama, Institute of Laser Engineering, Osaka University, Japan; Yasuji Kozaki, Fusion and Advanced Technology Systems Division National Institute for Fusion Science (NIFS) National Institutes of Natural Sciences (NINS), Japan; Xing Zhong Li, Department of Physics, Tsinghua University, China; Masayuki Nagami, Department of Fusion Plasma Research, Naka Fusion Research Establishment, Japan; Francis Thio, Office of Fusion Energy Sciences, U.S. Department of Energy, MD, USA; Vladimir Voitsenya, Institute of Plasma Physics, Kharkov Institute of Physics and Technology, Ukraine; Simon Woodruff, University of Washington, WA, USA; M. Zakaullah, Plasma Physics Laboratory, Quaid-i-Azam University, Pakistan

How well they review various papers, I do not know.


Also the distribution function used by Rider is given as

$$f(v)=nK(e^{[-(v-v_0)^2/v_{ts}^2]}+e^{[-(v+v_0)^2/v_{ts}^2]})$$ in this case for v < v₀.

I can't comment on the validity of claims without looking at other references, which I don't have.

 

[Astronuc]

Thomas Dolan's textbook - Fusion Research, 1982

http://www.fusionnow.org/dolan.html

Excellent reference on fusion research.

 

[cuddihy]

Thats trading off kinetic energy for electrical potential energy, analogous to a mechanical pendulum in motion. There's little net energy loss for the ion. The idea mentioned above is about speed-up (heating) and slow-downs (cooling) ~ instantaneously due to collisions w/ other ions. Imagine again your single ion passing the well center at its maximum speed. Statistically, two undesirable things can happen upon if it collide. Crudely put: a) it gives up all its speed in a head-on or the like, and then its too slow to fuse and its stuck in the well, b) it gets 'rear ended' and speeds up so that it escapes the well and its energy is lost.

If you don't accept the supposition that particle velocity distributions in an IEC device will be isotropic (the basic assumption of Rider's model), both (a) and (b) seem like silly concerns.

How do you get an isotropic ion velocity distribution in a potential well?

To see how silly (b) is, consider the potential well to be a gravity potential energy well, like one of those funnels you can drop marbles into. What are the odds that two marbles will collide, resulting in one of them being ejected from the funnel?

What about (a)? If a fuel ion loses sufficient energy, it will spend more time in the focus, and although it will be moving slower, it will be more likely to be hit by a faster moving ion.
This is a bigger concern, but here again Rostoker is right --there's no way to calculate this in the general sense. You would have to actually know the densities, energy distributions, and all effects combined. You can't calculate the general collision lifetime of a neutral spherical plasma ball and figure that's the same answer as for a specific device with an electrostatic gradient, different densities at different locations, and unspecified electron energies.

 

[RogerFox]

To see how silly (b) is, consider the potential well to be a gravity potential energy well, like one of those funnels you can drop marbles into. What are the odds that two marbles will collide, resulting in one of them being ejected from the funnel?

Like ah...a potential well that imparts enough energy to ions to escape the potential well... is not a potential well... no? Maybe .. ?

 

[jambaugh]

In reply to the original post, I would mention some of the other problems with magnetic confinement fusion designs.

Specifically there are confinement stability issues (kink and pinch instabilities). Bussard notes in the Google talk that these are not present in the IEC designs since the magnetic fields are convex to the plasma.

With regard to the laser based inertial confinement fusion, as e.g. LANL's Shiva and Argus driven systems, there is no real hope of power generation at this time. For the most part these methods are useful for abstract research into fusion physics including weapons issues.

These electron thermalization issues not withstanding I think Bussard's program deserves much more study before being dismissed, especially relative to Tokomak's et al.

Given the economic feasibility for IEC design as a neutron source one would then imagine if any design might be scaled to power production levels this one would.

Much of the debate here sounds like a call for more research into Bussard's idea. Even if power generation is never achieved the research may yet yield fruitful applications in say using the design to "burn" (i.e. transmute) nuclear waste thereby improving things for fission power. And I'm inclined to hope that Bussard's design can achieve power generation.

 

[mheslep]

If you don't accept the supposition that particle velocity distributions in an IEC device will be isotropic (the basic assumption of Rider's model), both (a) and (b) seem like silly concerns.
How do you get an isotropic ion velocity distribution in a potential well?

In a spherical IEC designs (fusors, Bussard Polywell) its given that ions approach the focus from all sides. I don't know about the Rostoker collider. In any case you'd have to enlighten me how a non-isotropic design, say only two collinear beams, doesn't suffer the same maxwellian fate.

To see how silly (b) is, consider the potential well to be a gravity potential energy well, like one of those funnels you can drop marbles into. What are the odds that two marbles will collide, resulting in one of them being ejected from the funnel?

Work the physics of your 'silly' analogy a little harder. Try bowl, not funnel. Take the friction away from the surface, make the marbles perfectly elastic and they will indeed bounce out, statistically. Your analogy as stated would have all the gas molecues in a container simply sink to the bottom.

What about (a)? If a fuel ion loses sufficient energy, it will spend more time in the focus, and although it will be moving slower, it will be more likely to be hit by a faster moving ion.

So? It gets hit but being slow it will likely not fuse. It just further randomizes the energy.

This is a bigger concern, but here again Rostoker is right --there's no way to calculate this in the general sense. You would have to actually know the densities, energy distributions, and all effects combined. You can't calculate the general collision lifetime of a neutral spherical plasma ball and figure that's the same answer as for a specific device with an electrostatic gradient, different densities at different locations, and unspecified electron energies.

Fusion by claim of the various designs only happens in the core or center 5% of the spherical devices, the only place by claim that density and ion energy is high enough for significant fusion. So one doesn't have to treat the entire device. Specifically, where do you see Rider mathematically wrong?

 

[mheslep]

With regard to the laser based inertial confinement fusion, as e.g. LANL's Shiva and Argus driven systems, there is no real hope of power generation at this time. For the most part these methods are useful for abstract research into fusion physics including weapons issues.

Ha! Then please engage Morbius the subject:
https://www.physicsforums.com/showpost.php?p=1367374&postcount=42
https://www.physicsforums.com/showpost.php?p=1367512&postcount=44
https://www.physicsforums.com/showpost.php?p=1367704&postcount=46

These electron thermalization issues not withstanding I think Bussard's program deserves much more study before being dismissed, especially relative to Tokomak's et al.

Given the economic feasibility for IEC design as a neutron source one would then imagine if any design might be scaled to power production levels this one would.

Why, technically since this is PF, would you favor the Bussard approach over one of many others?(no Tokamaks, no lasers):
http://http://www.topix.net/science/physics/2007/06/tri-alpha-energy-raises-40-million-in-venture-capital-for-nuclear-fusion"
http://www.google.com/url?sa=t&ct=r...QQ6BlJavkU4ndA6Q&sig2=4N3GRedtUCTyqQwYAQoIcA"
http://www.sandia.gov/news/resources/releases/2007/rapid-fire-pulse.html"
do dah
do dah

 

[RogerFox]

These electron thermalization issues not withstanding I think Bussard's program deserves much more study before being dismissed, especially relative to Tokomak's et al.

Agreed, ITER @ 13 billion vs WB7 @ 2 million.
IF WB7 validates WB6, but in a more open source/public manor, then a truncated dodec (WB8) is in order. If WB8 works, then scale up the size, maybe to 1 meter. Then do it again. As long as the previous device shows that the next step is worth it, keep building & testing.

Politics aside, Rider vs Bussard in the DOD, the DOD did fund IIRC 8 or 9 separate devices by Bussard. Funding contingent on the previous devices results of course.

If LN2 cooling is used then WB7 might be robust enough to run for some 10's of minutes. That would be interesting.

EDIT to add:

Us enthusiasts are making a recipe:

" preliminary specs for WB-7x of 4500 Gauss continuous at up to 75 KV drive with 25 Amps current. "

http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=5367&posts=1421#M158266

 

[sunday]

Foger,

That is a serious accusation against Dr. Ridder. His supposed motives are orthogonal to the actual discussion-the question is if his maths are correct, or not.

Best regards.

JL Domingo

 

[mheslep]

2nd that. Roger - If you can't provide evidence recommend you delete post #43 immediately.

mheslep

 

[cuddihy]

In a spherical IEC designs (fusors, Bussard Polywell) its given that ions approach the focus from all sides. I don't know about the Rostoker collider.

I don't know about the Rostoker collider either.

First, Rider never disputes the possibility of an electrostatic potential well forming.

Isotropic velocity distribution in a plasma will always mean rapid Maxwellization. But particles approaching the focus from all sides =/= "isotropic velocity distribution" any more than a linear accelerator has an isotropic velocity distribution.
True enough, once you prove Maxwellianization will occur, isotropic velocity distribution will be an aspect of the resulting plasma. But starting with that assumption is rather circular.

Velocity components in any kind of electrostatic fusor will be overwelmingly radial, the closer to the focus the particle is. There's really no question that that cannot be termed "isotropic" without distorting the meaning of the term beyond recognition.

In any case you'd have to enlighten me how a non-isotropic design, say only two collinear beams, doesn't suffer the same maxwellian fate.

No electrostatically accelerated fusion macine will suffer this fate, unless the electric potential breaks down. Rider didn't touch that.

Work the physics of your 'silly' analogy a little harder. Try bowl, not funnel. Take the friction away from the surface, make the marbles perfectly elastic and they will indeed bounce out, statistically. Your analogy as stated would have all the gas molecues in a container simply sink to the bottom.

Ok, oversimplied the analogy. *Some* of the marbles will bounce out. *some* of them will also fuse.

So? It gets hit but being slow it will likely not fuse. It just further randomizes the energy.

Fusion by claim of the various designs only happens in the core or center 5% of the spherical devices, the only place by claim that density and ion energy is high enough for significant fusion. So one doesn't have to treat the entire device. Specifically, where do you see Rider mathematically wrong?

The same place as Rostoker, -- pretty much from the start. To begin with, he continually conflates ion temperature and velocity--once again, a useful concept in an isotropic Maxwell-Boltzmann distribution, questionable in an accelerator. That leads him to the assumption of the isotropic collision operator as noted by Rostoker referred to above.

His "maximally efficient system for maintaining a non-equilibrium distribution", the basis of his model, (page 69 if you're looking at his dissertation) is an unnecessary application of heat thermodynamics that leads to the search for "recirculating power," a nonsense concept for an accelerator. It's a self-licking ice cream cone of a model which presupposes its conclusions as initial conditions. You could use this model to prove a lightbulb doesn't work.

 

[RogerFox]

LOL. I'll edit. But...

http://dspace.mit.edu/bitstream/1721.1/29869/1/31763419.pdf

Please read Riders acknowledgments, specifically look for the Office of Naval Research (ONR). Page 3 of the pdf. Looks like the ONR gave Rider a fellowship...

"the author is partially owned and operated by a graduate fellowship from the Office of Naval research"

..which is not exactly bought and paid for, so the edit.. but that is a poor choice of wording... don't you think...

 

[RogerFox]

Ok, oversimplied the analogy. *Some* of the marbles will bounce out. *some* of them will also fuse.

As velocity increases, does the particle become inelastic...above a certain velocity... ?

I just started reading: Theory of Thermionic Vacuum Tubes by E. Leon Chaffee

Since WB6 was basically a vacuum tube diode...

 

[sunday]

LOL. I'll edit. But...

http://dspace.mit.edu/bitstream/1721.1/29869/1/31763419.pdf

Please read Riders acknowledgments, specifically look for the Office of Naval Research (ONR). Page 3 of the pdf. Looks like the ONR gave Rider a fellowship...

"the author is partially owned and operated by a graduate fellowship from the Office of Naval research"

..which is not exactly bought and paid for, so the edit.. but that is a poor choice of wording... don't you think...

Yep, but one can always suppose that Ridder said that in tongue-in-cheek mode. I don't think a jest like that should be used to destroy the credibility of a scientist.

 

[cuddihy]

LOL. I'll edit. But...

http://dspace.mit.edu/bitstream/1721.1/29869/1/31763419.pdf

Please read Riders acknowledgments, specifically look for the Office of Naval Research (ONR). Page 3 of the pdf. Looks like the ONR gave Rider a fellowship...

"the author is partially owned and operated by a graduate fellowship from the Office of Naval research"

..which is not exactly bought and paid for, so the edit.. but that is a poor choice of wording... don't you think...

I think you're reading a little too much into his motives, here, Roger. Let's not forget Rostoker and Bussard were also each partially funded by the Office of Naval Research, albeit different parts of the office. What Bussard alleged about the politics is that his program was deliberately funded low to keep the budget below the threshold where DOE congressional staffers (not ONR) would see the program and request it killed. This isn't nefarious, just the way ricebowl budgeting works in our federal government.

What is a possibility about Rider's thesis, although there's no direct evidence to support it--in fact, Rider is pretty careful in his wording to hedge his results--(albeit in an arrogant way that suggests in the intro & conclusion summaries that he has successfully and self-eveidently ruled out all aneutronic fusion modes,)-- is that Rider bit off more than was reasonable to chew through for his subject thesis and dissertation, and once he realized it, facing a scholarship /funding window, he had to finish out with an overly simplistic, entirely analytical "general" model of aneutronic fusion machines.

It does take a high sense of self worth to assert that it is possible to create a universally applicable thermodynamic model of all possible fusion machines--Rider does this in a few paragraphs of part III of his dissertation. Although he doesn't claim so, this is the equivalent of fully creating and explaining the thermodynamic model of the carnot cycle, with all attendant ramifications, as an aside. If this were really a useful model or analysis, other plasma physicists would have picked up this model for use in their other fusion projects. Instead, it's only purpose has been, as Rostoker says, to discredit all forms of fusion not using D-T in a tokamok.

What would support this conclusion is the fact that, as you've stated, Rider went off in an completely different direction as soon as his defense was completed. Why go so far afield when you've invested so much time and effort? Why not fully flesh out the results of your analysis, unless, you think you've just created Beethoven's 9th, and nothing further can be done to make it better. Like I said, not exactly humble.

Anyway, this is just my opinion.

 

[cuddihy]

It's a self-licking ice cream cone of a model which presupposes its conclusions as initial conditions. You could use this model to prove a lightbulb doesn't work.

Let me just clarify, this was hyperbole. But this model could easily be used to prove that a Hirsch-Farnsworth fusor will not work, because the same thermodynamic conditions would apply as apply in a polywell. No part of this thermodynamic model is dependent on the power level, so it's not an aspect of the level fusors operate at either.

But the existence of fusors, the fact that they work exactly as theory says they should, belies the entire model.

 

[mheslep]

No electrostatically accelerated fusion machine will suffer this fate, unless the electric potential breaks down. Rider didn't touch that.

Ok, I think I see where you are going with this now: The presence of the of the E field would somehow prevent energy distribution from becoming Maxwellian? I disagree. The E field can not reduce the entropy of the ions over time, it will only add a 'drift' bias on top of the Maxwellian distribution.
Why?
From Rider 3.77 in Fundamentals... the change in entropy over time due to the externally applied E-M field is
$$\frac{\partial{S}}{\partial{t}}=-\frac{Z_e}{m}\int{d^3vf( \textrm{ln} f + 3/2 )[(\nabla_v\cdot E)-\frac{v}{c}\cdot (\nabla_v \times B)]=0$$
where:
$$S$$ is entropy
$$E, B$$ are the externally applied fields.
Since $$\frac{v}{c}=\approx0$$ for ions in an IEC device and $$(\nabla_v\cdot E)=0$$ then then whole is ~ zero.
Or, per Rider, ".... is zero because the electric and magnetic fields do not depend of the velocities of the particles perceiving them (barring relativistic..)"

mheslep

 

[M. Simon]

It is all about gain.

Ha! Then please engage Morbius the subject:
https://www.physicsforums.com/showpost.php?p=1367374&postcount=42
https://www.physicsforums.com/showpost.php?p=1367512&postcount=44
https://www.physicsforums.com/showpost.php?p=1367704&postcount=46


Why, technically since this is PF, would you favor the Bussard approach over one of many others?(no Tokamaks, no lasers):
http://http://www.topix.net/science/physics/2007/06/tri-alpha-energy-raises-40-million-in-venture-capital-for-nuclear-fusion"
http://www.google.com/url?sa=t&ct=r...QQ6BlJavkU4ndA6Q&sig2=4N3GRedtUCTyqQwYAQoIcA"
http://www.sandia.gov/news/resources/releases/2007/rapid-fire-pulse.html"
do dah
do dah

If you look at Rostoker's numbers you get drive energy requirements proportional to mass. Protons get 300 Kev. B11 gets 3.3 Mev.

In the Bussard reactor (I have calculated it myself) drive is proportional to electric charge. Protons get 200 Kev. B11 gets 1.0 Mev.

With a reaction that gives off 8.68 Mev that is quite a hefty trade off.

The Bussard reactor has more gain margin.

 

[M. Simon]

Maxwell was a demon

There is Maxwellianization at the center and at the edges. In the high density high energy region (center) energies scatter. In the high density low energy region (edge) it gets all redistributed at a lower energy so it re-peaks the distribution.

Or so the theory goes.

I'd like to build one and see if its true.

Ok, I think I see where you are going with this now: The presence of the of the E field would somehow prevent energy distribution from becoming Maxwellian? I disagree. The E field can not reduce the entropy of the ions over time, it will only add a 'drift' bias on top of the Maxwellian distribution.
Why?
From Rider 3.77 in Fundamentals... the change in entropy over time due to the externally applied E-M field is
$$\frac{\partial{S}}{\partial{t}}=-\frac{Z_e}{m}\int{d^3vf(lnf+\frac{3}{2})[(\nabla_v\cdot E)-\frac{v}{c}\cdot (\nabla_v \times B)]=0$$
where:
$$S$$ is entropy
$$E, B$$ are the externally applied fields.
Since $$\frac{v}{c}=\approx0$$ for ions in an IEC device and $$(\nabla_v\cdot E)=0$$ then then whole is ~ zero.
Or, per Rider, ".... is zero because the electric and magnetic fields do not depend of the velocities of the particles perceiving them (barring relativistic..)"

mheslep

 

[mheslep]

If you look at Rostoker's numbers you get drive energy requirements proportional to mass. Protons get 300 Kev. B11 gets 3.3 Mev.

In the Bussard reactor (I have calculated it myself) drive is proportional to electric charge. Protons get 200 Kev. B11 gets 1.0 Mev.

With a reaction that gives off 8.68 Mev that is quite a hefty trade off.

The Bussard reactor has more gain margin.

What are you talking about? Pls don't hand-wave in this engineering forum - move over to general discussion. Which Rostoker numbers are proportional to mass? How are you defining gain in this context? Hefty trade-off?

 

[mheslep]

There is Maxwellianization at the center and at the edges. In the high density high energy region (center) energies scatter. In the high density low energy region (edge) it gets all redistributed at a lower energy so it re-peaks the distribution.

Or so the theory goes.

I'd like to build one and see if its true.

Please see
https://www.physicsforums.com/showthread.php?t=5374

 

[sunday]

In the discussion about the Polywell topic in Wikipedia (http://en.wikipedia.org/wiki/Talk:Polywell), there is an interesting, if intuitive, approximation to velocity distribution in a polywell.

Regrettably, the author is unknown:

(...)
Regarding Maxwellianization, this is how i see it: the well establishes a relationship between the ions distance from the center and it's radial velocity. It's velocity perpendicular to it's radial velocity is essentially an angular velocity. So let's split this up into radial and angular velocities:

angular velocity: Assuming for a moment that the angular veocity for each ion is mantained (inertial), as the ion gets closer to the center the angular velocity's contribution to the kinetic energy decreases, such that when it's in the center it is exactly zero. (because a ball traveling in a circle of radius r at angular velocity 2pi is traveling with linear velocity 2pi*r.) So as ions approach the center, their angular velocity components become non-maxwellian, such that at the center they are all exactly the same: 0.

Now, dropping that assumption, the rule still applies, because it's a law of geometry (translation of coordinate systems). However, we add in maxwellianization of the angular velocity, which will make their angular velocities approach an average, with a normal distribution. That average, since as many will be going clockwise as counterclockwise, is zero. It is only a matter of what the standard deviation of the normal distribution is. Or, more precisely, how fast the standard deviation increases or decreases with respect to the distance from the center. (This is really a crude model, because they do not actually linear velocity perpendicular to their radial velocity as they go away from the center. their angular velocity decreases. the trajectory (in two dimensions) would look more like a polar rose or trefoil knot.) in any case, it seems to me that maxwellianization will tend to reduce the standard deviation of their angular velocities, leading to better focus.

radial velocity: Again, starting with the simpler non-maxwellian case: because of the radial electrostatic gradient, the radial velocity of an ion will be a function of its initial radial velocity and distance from the center. To simplify this, one can combine initial distance from center and radial velocity by finding the distance from the center in which the radial velocity is zero. Thus, if they all start from the same distance from the center at which the radial velocity is zero (disregarding that this is quasi-spherical rather than spherical), they will all have the same radial velocity at any given distance from the center.

Ideally, they all have zero radial velocity at the very outer edge of the sphere, thus giving them maximum kinetic energy at the center. this is what the polywell attempts to do by using microwaves to ionize the gas. according to mainstream scientific theory, the ionization rate will depend largely on how well matched the magnetic field strength at the point of ionization is to the frequency of the microwave radiation. Thus, since the magnetic field strength decreases as one goes towards the center, one can set the microwave frequency such that it ionizes the most at the very edge of the sphere.

So now let's take into account maxwellianization of the radial velocity component. And here is the key: potential energy does not maxwellianize. Sure, they will maxwellianize on the outside, all to the same low average velocity (and thus low standard deviation (i.e. "temperature"). But, since their initial distance from the center of the ions is all about the same (the very edge, where the gas is ionized), and their velocities (KE) are relatively low in comparison to their potential energy (the huge voltage gradient between the center and the outside), as they go toward the center they will be accelerated at the same rate, and thus their radial velocities relative to each other will stay the same. since maxwellianization is a function of velocities relative to each other, and not absolute velocities(throwing ice in space won't make it melt), maxwellianization will occur at the same rate, and their standard deviation ("temperature") will not increase as they go towards the center, even though their average KE gets much higher.

Now this doesn't take into account the fact that as ions are going towards the center, the same number of ions are going away from the center, at the same average radial velocity. So you have two sets of ions whose relative radial velocities are higher and higher as you approach the center. That is a possible source of additional maxwellianization. As I understand it, if they are flying past each other very fast, the ions going in opposite directions spend so little time at any distance from each other where inter-atomic forces would be significant that tehy don't really affect each other. So maxwellianization between inbound and outbound ions would occur at a higher rate as you get further from the center. - a maxwellianization that leads to zero average radial velocity. This causes the ions' "distance from the center at which their radial velocity is zero" to approach "far from the center" quicker than it approaches "close to the center". Leading towards the ideal condition mentioned earlier.

That's all very rough. Forgive me: I don't really know what I'm talking about. 69.131.30.74 00:59, 8 April 2007 (UTC)

Pity I haven't got the maths to model that intuition. My last battles with multidimensional differential operators were just before the fall of the Berlin Wall...

Comments?

 

[mheslep]

Comments?

Forgive me: I don't really know what I'm talking about

He/She's right.

 

[sunday]

He/She's right.

With the due respect, Why?

 

[M. Simon]

What are you talking about? Pls don't hand-wave in this engineering forum - move over to general discussion. Which Rostoker numbers are proportional to mass? How are you defining gain in this context? Hefty trade-off?

I take it you haven't read Rostoker 2004. Pity.

You can stop the hand waving now.

Gain = Energy out / drive energy.

Gain Bussard pB11 = 8.68Mev / 1.2 Mev
Gain Rostoker pB11 = 8.68 Mev / 3.6 Mev

This is the ultimate gain. Actual gain will be less.

BTW how you coming on the vacuum tube book (Chafee)?

 

[RogerFox]

Let's not forget Rostoker and Bussard were also each partially funded by the Office of Naval Research,...
this is just my opinion.

Right, both got ONR $$, I thought that was the point I was making...
AS far as the rest of your observations about Rider, very well said.
It is, at the very least a very strange story.

cuddihy, did you catch my bit on vacuum tubes circa 1933, and inelastic particles upthread? Since we are dealing with an ion accelerator.. are the ions going fast enough to become inelastic? If they are, they don't bounce...no?

if there is bounce we are talking about imparting spin... or exciting.. electrons changing orbits... no ?

I'm asking, because I'm not sure I have it right.

 

[mheslep]

BTW how you coming on the vacuum tube book (Chafee)?

What happened to your posted link to that copyrighted book?

 

[RogerFox]

Yep, but one can always suppose that Ridder said that in tongue-in-cheek mode. I don't think a jest like that should be used to destroy the credibility of a scientist.

Nevertheless, Rider got a fellowship. If there was some gamesmanship, it was thru Rider's & the ONR's action and not mine. Rider took the money & ran away to work another field... no?

Forget the hyperbole, that I have introduced, forget it. Look at Riders actions.

 

[mheslep]

With the due respect, Why?

The argument is hard for me to parse. The part on angular momentum is just wrong about a basic conservation law.

So as ions approach the center, their angular velocity components become non-maxwellian, such that at the center they are all exactly the same: 0.

If a particle has somehow acquired some angular momentum (via a collision say) on the edge its not going become zero as falls down a radial potential gradient. The non zero angular mo means the particle will form some kind of orbit about the center, it will be defocused compared to a radially traveling particle, and in fact will never go through the center until/unless some other force other than the external qE force acts on it (another collision say). Its Phy mechanics 101.
And so on.

See Nevins for a good, mathematically modeled treatment:
"http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PHPAEN000002000010003804000001&idtype=cvips&gifs=yes" ", W.M Nevins Physics of Plasmas 2, 3804, 1995.

 

[sunday]

The argument is hard for me to parse. The part on angular momentum is just wrong about a basic conservation law.


If a particle has somehow acquired some angular momentum (via a collision say) on the edge its not going become zero as falls down a radial potential gradient. The non zero angular mo means the particle will form some kind of orbit about the center, it will be defocused compared to a radially traveling particle, and in fact will never go through the center until/unless some other force other than the external qE force acts on it (another collision say). Its Phy mechanics 101.
And so on.

See Nevins for a good, mathematically modeled treatment:
"http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PHPAEN000002000010003804000001&idtype=cvips&gifs=yes" ", W.M Nevins Physics of Plasmas 2, 3804, 1995.

Yes, about radial velocities, I agree. But I find the part about radial velocities acceptable.

I have no access to the full text of the cited paper...

 

[RogerFox]

Sunday:

http://www.osti.gov/bridge/servlets/purl/41400-kmR97s/webviewable/41400.pdf

 

[M. Simon]

What happened to your posted link to that copyrighted book?

The copyright has expired.

It is public domain. These things happen.

Despite that fact it appears that the link has been removed.

Pity. A lot to learn there.

Well if you look around you can find it.

 

[M. Simon]

I've found that most of the technical books published before about 1964 never had their copyrights renewed, so now are in the public domain. So I am endeavoring to digitize and post some selected books relating to the "vacuum tube age" of electronics here.

I have checked to the best of my ability to confirm that these works have expired copyrights and are now in the public domain. If you have information to the contrary, please contact me at:

For information about copyrights and copyright renewals, look here. Here's a nice, easy copyright renewal search tool.

Want to help? If you have any pre-1964 books relating to vacuum tube technology, radio, or electronics that you'd like to sacrifice, let me know. And when I say "sacrifice", I really do mean sacrifice - the way I do this is to cut the book loose from it's cover, then slice the pages away from the binding. This way I can send it through an automatic document feeder. I can scan a 400 page book in about one hour. I'll have to verify that the copyright is expired and has not been reviewed - I can do that before you send anything.

From:

http://www.pmillett.com/tecnical_books_online.htm

Which has lots more books on tubes.

I recommend it.

 

[RogerFox]

John F. Santarius
University of Wisconsin

Injected electrons form a cloud throughout the interior of the sphere, resulting in a negative electrostatic potential well, as shown in Fig. 3. Ions are injected at low energy or created by neutral gas ionization at the outer edge of the electron cloud. These ions fall down the potential hill and converge on the origin of the sphere, giving a small, spherical core of high density (see Fig. 2). For a sufficiently deep potential well, steady-state fusion power can be generated in this core. Preliminary investigations of the Polywelltm concept have led to the conclusion that it can be a viable fusion reactor [2, 12-14],

2. R.W. Bussard, "Some Physics Considerations of Magnetic Inertial-Electrostatic Confinement: A New Concept for Spherical Converging-flow Fusion," Fusion Technology 19, 273 (1991).

12. N.A. Krall, "The Polywell: A Sperically Convergent Ion Focus Concept," Fusion Technology 22, 42 (1992).

13. M. Rosenberg and N.A. Krall, "The effect of collisions in maintaining a non-Maxwellian plasma distribution in a spherically convergent ion focus," Phys. Fluids B 4, 1788 (1992).14. S.K. Wong and N.A. Krall, "Potential well formation by injection of electrons with various energy distributions into a sphere or a slab," Physics of Fluids B 4, 4140 (1992).

although several questions remain [15, 16].

15. W.M. Nevins, "Can Inertial Electrostatic Confinement Work Beyond the Ion-Ion Collisional Time Scale?," Physics of Plasmas 2, 3804 (1995).

16. T.H. Rider, "A general critique of inertial-electrostatic confinement fusion systems," Physics of Plasmas 2, 1853 (1995).

http://fti.neep.wisc.edu/iec/inertial_electrostatic_confineme.htm

Santarius cites article pro & con, offering both sides for your consideration. From one of 2 (IIRC) University IEC programs in the US, (Urbana is the second, U of Wis has a working IEC reactor).

Dr. Kulcinski with IEC device

http://fti.neep.wisc.edu/iec/potential_uses.htm

Grahic: Likelihood of fusion
http://fti.neep.wisc.edu/iec/operat1.gif

Peer reviewed work from U of Wis. #10 looks good.

http://fti.neep.wisc.edu/iec/peer_reviewed.htm

 

[RogerFox]

Which has lots more books on tubes.

IIRC it was Bussard who said that a polywell device such as WB6 is more akin to a vacuum tube than a Tokamak, so would WB6 be a diode? Thats what I infered from the intro in Chaffee's book. WB6 is a Vacume tube diode. ..?