Talk:Aneutronic fusion

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[edit] Consistent data set

Independent of the blood being shed on the front, I would like to come to an agreeement on the data we use, starting with <σv> as a function of temperature. The numbers I use are verifiable, but I think they come from multiple sources and may not be entirely consistent. Can we agree to use the functional form and coefficients given in

Cox, Larry T., Thermonuclear Reaction Bibliography with Cross Section Data for Four Advanced Reactions.,
AF-TR-90-053, Edwards Air Force Base: Phillips Laboratory Technical Services Office, 1991

and reproduced here? I'm open to other suggestions. --Art Carlson 08:19, 27 September 2006 (UTC)

[edit] New proposal for power density

(To avoid confusion, please limit comments in this section to the proposal above. Comments on other content should be put in the appropriate section. --Art Carlson 08:40, 3 October 2006 (UTC))

In every published fusion power plant design, the part of the plant that produces the fusion reactions is much more expensive than the part that converts the nuclear power to electricity. In that case, as indeed in most power systems, the power density is a very important characteristic. If the power density can be doubled without changing the design too much, then the cost of electricity will be at least halved. In addition, the confinement time required depends on the power density.
It is, however, not trivial to compare the power density produced by two different fusion fuel cycles. The case most favorable to p-B11 relative to D-T fuel is a (hypotheical) confinement device that only works well at ion temperatures above about 400 keV, where the reaction rate parameter <σ'v> is equal for the two fuels, and that runs with low electron temperature. In terms of confinement time required, p-B11 would even have an advantage, because the energy of the charged products of that reaction is two and a half times higher than that for D-T. As soon as these assumptions are relaxed, for example by considering hot electrons, by allowing the D-T reaction to run at a lower temperature, or by including the energy of the neutrons in the calculation, the power density advantage shifts back to D-T.
The most common assumption is to compare the power densities at the same pressure, with the ion temperature for each reaction chosen to maximize the power density, and with the electron temperature equal to the ion temperature. Although confinement schemes can be and sometimes are limited by other factors, most well-investigated schemes have, not surprisingly, some kind of pressure limit. Under these assumptions, the power density for p-B11 is about 2100 times smaller than that for D-T. If the device runs with cold electrons, the ratio is still about 700.

Are there specific objections to (1) the factual accuracy, (2) the point of view, or (3) the editorial style of this version? I tried to do justice to the complexity of the issue without being long-winded. Inline citations would be desirable. Footnotes could be used to add information or to reduce the length of the main text. We can talk about the exact values I used for the numbers. --Art Carlson 08:48, 2 October 2006 (UTC)

To make myself perfectly clear, I consider this expanded version to be adequate reply to Eric's objection that the two-sentence version did not do justice to the complexity of the issue. I will leave it here for a few days, during which time I consider Eric (or any other active editor) obligated to detail any objections. If no comments or suggestions are made (in enough detail that they can be responded to), I will consider this the consensus version, put it on the live page, and defend it against unargued or blanket reverts. --Art Carlson 09:48, 2 October 2006 (UTC)

Sure, Art, there is a lot wrong with that factually. First is the assumption that in any fusion device the cost is dominated by energy production, not conversion. That is the case for tokamak, but not, for example for the DPF. A tokamak without energy conversion that is capable of producing a GW of energy will, by any estimate I know of, have a capital cost in excess of $2/W, probably a lot in excess. A DPF, without energy conversion equipment, that is capable of reaching the breakeven conditions outlined in my own published research costs about $150,000 with current low production rates of components such as capacitors and fast switches. (This figure can be easily verified since I have priced the components myself.) It would be capable of producing 5 MW of net power, so has a cost of about $0.03/W. In that case the total cost is dominated by the cost of conversion, which would be around $0.80/W for thermal conversion, but probably around $0.10/W for direct conversion, again based on low-volume production.
A careful reading of what we both wrote shows that there is no disagreement on the facts. Since you evidently misunderstood me, we obviously need to work on the clarity. I first point out that the costs in published fusion power plant designs, like the tokamak designs you mention but not limited to them, are dominated by the nuclear island. I do not doubt that you have made some estimates for a DPF plant that are dominated by the balance of plant.--Art Carlson 21:18, 3 October 2006 (UTC)
Second, the power density of the reacting plasma does not have a direct link to costs. In the DPF, the reaction takes place in a volume that is tiny compared with the total size of the device and in a time that is a small fraction of the pulse repetition time. Therefore comparing power density in a DPF to that of a tokamak would give an estimate of relative cost that would be many orders of magnitude in error.
In other words, a DPF can produce enormously higher pressure per dollar than a tokamak. But the cost of power is not in the same ratio, although the DPF would be about two orders of magnitude cheaper.
It is tempting - but, as you point out, invalid - to estimate the output of a fusion plant by multiplying the fusion power density with some volume such as that of the reaction chamber. This is one of many reasons that, as we both agree, power density figures are totally useless to compare different power plant concepts like tokamaks and DPF. That is why I have never done so. My text specifically compares "two different fusion fuel cycles". So again, on a careful reading, we do not disagree on the facts.--Art Carlson 21:18, 3 October 2006 (UTC)
So altogether, the paragraphs are not accurate. Nor is the paragraph that you have, for the same reasons, so I am going back to my paragraph, which is accurate.Elerner 02:29, 3 October 2006 (UTC)
Now that it is clear that the problem lies more in understanding what I wrote, perhaps you can suggest a version that you find clearer? --Art Carlson 21:18, 3 October 2006 (UTC)

It has now been 9 days since I posted this proposal and 8 days since the last comments were made. Therefore I have incorporated it into the article. Improvements are welcome, but blanket reverts are out-of-place, --Art Carlson 08:06, 11 October 2006 (UTC)

[edit] Eric's justification for his reversions

Since Eric seems to have difficulty focussing on detailed arguments, I have created this section to give him a leg up. Specifically, he has several times made a reversion essentially identical to this one. I provide space here for him to explain why he made each of these changes. --Art Carlson 20:56, 3 October 2006 (UTC)

1. It is better not to provide a wiki link to the Lawson criterion when discussing the Lawson criterion because ...

2. It is better not to provide a wiki link to a calculation of the confinement requirement for D-T vs. p-B11 when discussing the confinement requirement for D-T vs. p-B11 because ...

3. It is better not to provide a footnote explaining the hot ion mode, even though two of the three mechanisms discussed later for achieving p-B11 ignition use this mode, because ...

4. It is better not to provide a reference for the idea of bremsstrahlung absorption in pellet fusion because ...

5. It is better not to disambiguate the wiki link Pascal to Pascal (unit) because ...

This argument is not worth the time devoted to it. I have merged part of your paragraph with part of mine. I will narrow my objection to the fact that your claim that one measure is most imortant is totally unsourced and is your own original opinion, so does not belong there. Find a citation for it and then say "according to so and so..." other wise drop it.Elerner 18:33, 9 October 2006 (UTC)
I can live with that. Speaking of dropping it, I guess you saw the light about points 4 and 5. I'm still looking forward to hearing your reasons for maintaining points 1 through 3, though. --Art Carlson 19:14, 9 October 2006 (UTC)
oh, put them back in yourself without reverting and let's end this!Elerner 20:58, 9 October 2006 (UTC)
Glady. Just for the record, there were eight rounds of reversions due to these differences, which you now concede without having once justified them. I hope we can work more efficiently in the future. --Art Carlson 21:18, 9 October 2006 (UTC)

[edit] edits by EngineerScotty

You may not be aware of this, but aneutronic fusion has been studied in the laboratory for decades. The fact that it produces the bulk of its energy in charged particles is vaidated by thousands of experiments. To portray, as you do, known, undisputed physics as the opinions of a minority is a gross distortion. I don't want to get into a revert war again, but I think you should do a bit of research before piling in on this. I stronlgy suggest you rever the changes yourslef until you look a bit at the field.Elerner 00:41, 10 November 2006 (UTC)

Got your note--I have an interesting perspective on the article that you might consider--it might explain better the reactions of some on Wikipedia (and outside as well).
Adding references to the article would be good--inline references would be better. At any rate, processes or technologies which have been proposed--even if studied in detail--but which haven't been built, probably should use the subjunctive voice. I'm not at all equating the topic with perpetual motion machines (as WAS 4.250 did on the arb page), but many agree the technical hurdles are immense.
I should let you know that my professional line of work (a software engineer) has long taught me to be skeptical of claims which are based entirely on theory and not on practice (here being empirical research)--with exceptions granted for things like mathematics.
I'm not doubting the scientific claims at all, nor am I agreeing with them. I have no intellectual basis to do so, not being a physicist. I pretty much left them alone. However, when the article ventures forth from the purely theoretical, into questions of "how can we build a device which uses this far-off technology, how much will it cost, and what will other properties of this thing be", it crosses a big bright line from theoretical science into engineering--my turf. Discussing engineering parameters of device which we currently have no idea how to harness the underlying technology of, and speculating on its properties, while using the present tense--strikes me as highly inappropriate.
My preference for this article, after much reflection, would be to remove most if not all claims concerning the properties of a powerplant based on aneutronic fusion. Such engineering analyses are far too speculative to include in an encyclopedia at this state of the underlying technology (infancy), regardless of the soundness of the underyling science. The information on the underyling physics--the various reactions and their properties, what aneutronic fusion is--certainly should stay. The science parts of the article aren't bad (better sources would be nice), but the detailed commentary regarding how a reactor and energy conversion device might work are simply pie-in-the-sky at this point. If you were to get a multi-billion-dollar grant to study this, Eric, I suspect you'd be at least a decade away from having a laboratory reactor up and running, let alone being able to prototype a powerplant (let alone being able to build one that is cost-effective). To make claims--even couched as speculation--as to how efficient such a beast would be, is simply not appropriate here. And--not to be rude--it does look like a sales job.
Thoughts from others?
--EngineerScotty 01:24, 10 November 2006 (UTC)
I'm following this, and thinking about it. Fred Bauder 01:50, 10 November 2006 (UTC)
Might it become a principle in the case? :) --EngineerScotty 01:52, 10 November 2006 (UTC)
But your edits are flat-out wrong. Of course aneutronic fusion reactions have been produced in the laboratory. It is not a proposed form of fusion power--it is a well-known form.
Again, you're intermingling the raw science, with the technical application. Aneutronic fusion is certainly a well-known form of fusion; but it remains a "proposed" form of fusion power--nobody's built a functioning powerplant that operates using aneutronic fusion.
If you are trying to say that it has not produced net energy, that is true of all forms of fusion energy.
From the article, the only mention of an actual aneutronic reaction being produced is this passage: "In 2005, a Russian team produced hydrogen-boron aneutronic fusions using a picosecond laser[13]. However, the number of the resulting α particles (around 103 per laser pulse) was extremely low." Never mind being able to recover positive net energy--has anybody even sustained a chain reaction yet?
Fusion reactions are not chain reactions. You are thinking of fission--that is a different process. Please learn just a bit of the physics before chopping up the article.Elerner 02:10, 11 November 2006 (UTC)
Yet fusion engineering is an active field of study--there are whole departments devoted to it at some universities. It is not theory that aneutronic reactions produce almost all their energy as charged particles--it is undisputed laboratory findings for decades past.
That appears to be by definition.
If you eliminate from this article all discussion of engineering problems, you would have to knock out 80% of the article on fusion power, which deals with engineering problems of tokamaks.
A better solution, I think, would be to separate the aneutronic fusion and aneutronic fusion reactor--one could focus on the science, the other could focus on efforts to harness this sort of reaction.
Again, this article was gone over with a fine-toothed comb by Art Carlson, who is no friend of aneutronic fusion. Please don't take a bull-in-china-shop approach. Again I offer to provide review articles so you can see what the state of the field is.
Please. Also please note that you and Art do not constitute a consensus. While your work to improve the article is appreciated; many of us think it could be improved further.
Also we do not need a half billion dollars because the devices cost less than $300,000 to build. Many have been built--this is not theory this is ongoing experimental work dating back decades.Elerner 02:00, 10 November 2006 (UTC)
Which devices, exactly? And with what properties?
--EngineerScotty 17:55, 10 November 2006 (UTC)
Dense plasma focus is one device that is very cheap to build and has been researched experimentally for over forty years. This is not a new field--it is an ongoing program. Elerner 02:10, 11 November 2006 (UTC)

Elerner 02:00, 10 November 2006 (UTC)

I don't get this, "power," to me, means sustained output. This is a reaction, but not power. Fred Bauder 02:42, 10 November 2006 (UTC)
This is not correct. Power in science and engineering has a very specific meaning—energy produced per unit time. Fusion devices can produce power either continuously ( which has never been achieved, but is theorized as possible with some devices) or in pulses that are repeated. Aneutronic fusion is just another form of fusion energy from the more commonly studied DT reaction. It is no more theoretical than DT and has been studied experimentally very extensively. Fusion power has been produced in many devices and aneutronic fusion power has also been produced.
You are confusing “power” with “net power production”. That is very different. This is when you get more power out of the device than you put into it. This has not been achieved for any controlled fusion device
If you look at the “fusion power” article, you will see power is correctly referred to. None of the devices mentioned come at all close to producing “net power production”: more power produced than electricity than is needed to run the device. But they all are correctly described as producing power.Elerner 03:52, 10 November 2006 (UTC)
Still confusing. I know the Amazon is a "stream", but I don't think that's even mentioned in Amazon River. Fred Bauder 13:00, 10 November 2006 (UTC)
Did you look at the fusion power article? Rivers have nothing to do with this, but fusion power does. Please look at it and see the correct use of the terms.Elerner 02:10, 11 November 2006 (UTC)
I think the best approach to this article is that I will provide, over the next few days, additional verifiable references to everything that I can. Then you can get rid of things that are not cited? How about that?Elerner 02:10, 11 November 2006 (UTC)
I'm not very happy either with a lot of the edits by EngineerScotty. Unfortunately I won't have time before Thursday to go through them in detail. --Art Carlson 18:03, 11 November 2006 (UTC)

[edit] I think this section is wrong...

In the candidate area I found this passage:

"The next two reactions are usually treated as a chain in the hope of attaining an enhanced reactivity due to a non-thermal distribution. The product 3He from the first reaction..."

I believe this needs to be fixed. The first reaction has no 3H3 product, nor does the first reaction on the list. I think this needs to be re-arranged.

Maury 22:28, 16 November 2006 (UTC)

The reactions in question are
p + 6Li → 4He (1.7 MeV) + 3He (2.3 MeV)
3He + 6Li → 2 4He + p + 16.9 MeV
Add them together and you get
2 6Li → 3 4He
I suspect you were confused about which reactions I meant. Would it be better to number the reactions? --Art Carlson 09:09, 17 November 2006 (UTC)
I made some changes that might make things clearer. --Art Carlson 09:27, 17 November 2006 (UTC)
Yes, much better now. Maury 13:21, 23 November 2006 (UTC)

[edit] References in section on "Technical challenges"

We now have 12 inline references in fifty-some lines of text in Aneutronic fusion#Technical challenges. Do we still need the {{References}} template? --Art Carlson 10:00, 17 November 2006 (UTC)

[edit] Contradiction?

In every published fusion power plant design, the part of the plant that produces the fusion reactions is much more expensive than the part that converts the nuclear power to electricity.

This equipment is sufficiently expensive that about 80% of the capital cost of a typical fossil-fuel electric power generating station is in the thermal conversion equipment.[citation needed]

Not really a contradiction, but the latter seems irrelevant. — Omegatron 00:46, 23 November 2006 (UTC)

Actually I think with some re-wording this is actually useful information. If the second sentance is correct, and I believe it is, then it would seem the capital costs of a fusion plant would be very different, and that seems to be worth mentioning. That said, I'm not sure this is the proper article to do it in! Maury 19:04, 23 November 2006 (UTC)

[edit] Odd question, but...

I realize this might not be the right place to ask this, but it seems to be getting everyone's eyeballs, so...

Why is Bussard pushing aneutronic fusion? And for that matter, why does it seem that everyone with a "non-conventional" design (of which there are only a few, admittedly) always push aneutronic devices? Don't get me wrong, there are major advantages here that are evident to all, but given the fact that we're nowhere near ready to commercialize any design, wouldn't it be prudent to test using D-T to start with? Any of the reactions mentioned here are much more difficult to get working, so it would seem to me that any machine capable of supporting aneutronic fusion should be able to generate much higher rates using D-T, at least for a short time (embrittlement, etc.)

Is there some feature of the alternative designs that precludes this? As far as I am aware the initial fusion experiments in both the fusor and the migma used D-T, so I don't see any problems there. I don't fully understand Bussard's new design, but it doesn't seem to have any major differences that would require higher mass ions or anything that obvious like that.

Is there some sort of economic or legal issue here? Or is it, as it appears to these untrained eyes, a way of avoiding having to demonstrate the machines actually work at a small scale before moving on to the full-sized devices?

Maury 19:01, 23 November 2006 (UTC)

I never understood that either. There is certainly no compelling technical reason. (Psychologically, I suppose once you start divorcing yourself from reality there is no reason not to go whole hog.) When I brought up the advantages of using D-T in a dense plasma focus, Eric Lerner reacted very allergic. --Art Carlson 08:42, 24 November 2006 (UTC)
Bussard's experiments are D-D fusion, and he talks about burning up conventional nuclear waste in the neutron flux from D-T fusors. He also talks about retrofitting conventional power plants by tying the steam lines to external boron-blanketed D-T fusors. I don't understand why everyone's so hard on him when they clearly haven't paid any attention to what he's actually doing.
He clearly states that his proposed demonstration prototype would cost $150M for D-D or $200M for p-B11 and that the Navy is more interested in p-B11 for electric boats. He definitely likes the idea of aneutronic fusion (as anyone would), but it doesn't sound like he's being irrational about it to me.
He also emphasizes that the resulting alpha particles could be neutralized by grids to generate DC directly instead of the inefficient heating things up with neutrons and boiling water. I don't know if that's possible with other reactions. — Omegatron 23:34, 24 November 2006 (UTC)

[edit] p+6Li fusion efficiency?

The second paragraph doesn't give a very convincing explanation why this reaction chain is impractical:

p + 6Li   → 4He (1.7 MeV) + 3He (2.3 MeV)
3He + 6Li → 2 4He + p + 16.9 MeV
3He + 3He → 4He + 2 p

All it says is that the non-thermal distribution of 3He provides an insufficient enhancement to the later stages. Is the cross-section of 3He+6Li too low? Does electromagnatic repulsion require too high a reaction temperature? Can someone elaborate or reword this section a bit? --Dgies 21:04, 4 December 2006 (UTC)

[edit] Given Densities?

"For given densities of the reacting nuclei, the reaction rate for hydrogen boron achieves its peak rate at around 600 keV (6.6 billion degrees Celsius or 6.6 gigakelvins) while D-T has a peak at around 66 keV (730 million degrees Celsius)."

What are these "given densities" that the article speaks of, and why are they the important ones for aneutronic fusion such that the article mentions the (I assume) ion energy of the p11B peak for these particular densities and no others. -- TristanDC 20:51, 4 January 2007 (UTC)

It means, choose any densities you want, but keep then constant while you vary the temperature. No matter what densities you take, you will always find the maximum reaction rates to be maximum at 600 keV and 66 keV respectively. --Art Carlson 09:55, 5 January 2007 (UTC)
I'm going to change the wording to "For any given density of the reacting nuclei, ..." -- TristanDC 20:24, 6 January 2007 (UTC)

[edit] MHz theta pinch

Bp fusion engin thepry by MHz theta pinches plasma focus fybrid Toyokawa High Phyisics Labratory, Japan T&F 0533-87-3880, Shigetaka Ikegami

10~-6Ω　one turn resistance MHz strong magnetic field C-L resonance elements bundle first mode coil, 1m dia., is easy. It is found that linear relation between coil conductance and elements number is hold for C capacity part with air or gass space, as well as L fine coated wires number.　Vortex Jule loss is constant for 0.01mm dia. coated steel wires number. Theta pinch and plasma focus system hybrid is easy.

By Bp fusion engine the sea containing boron becomes more than oil. By BxJ acceleration of expanding magnetic field mat piston, 200～600kev velocity snowplow plasma of high density 10ev is possible. Skin current Jule heat is recovered by heat cycle. During acceleration and expansion, plasma is recombined with hｖ radiation. It is efficient to acclerate low density large volume ｐlasma by large width cylinder boundary, with slops for plasma slips to center boundary. At pinch, leaks from both plasma ends are impossible by composited millor magnetic field of skin current and axial focus current. Adiabatic compression without shock is considered. And verfied with shallow water suimlation experiment. High density is confitmed with isothermal ionizing cooling compression. High density small quanrity plasma dia. is vey very small. Pinch time, solitary wav pass time through pinched plasma, is vey small so that electron radiation is small. Fusion energy is larger than sum of all losses. Fusion energy, compressed plasma energy and piston magnetic field energy are compleatly recovered every MHz cycle by piston withdrow. Fusion pulses series generates power with efficiency of abou 0.6～0.7.

--(Contributed on 05:18, 2007 March 12 by user 211.129.222.223)

This is so incomprehensible that it is impossible to refute. More to the point, the citation of the source (if indeed that is what it is) is also incomprehensible. With all reluctance to revert without detailed discussion, I have no other choice here. --Art Carlson 11:34, 12 March 2007 (UTC)
OK. It looks like the ref. is S. Ikegami, "A new type of low-loss, strong-field RF coil for commercial nuclear fusion", Electrical Engineering in Japan, Vol.111, No.4, 1991, pp. 52-59. I can't find it online. I can check, but I doubt that it's in our library. Has anyone read this? Can anyone vouch for the reliability of the source? (peer-reviewed? conference proceedings?) Can anyone justify why this particular article/concept is notable enough to be singled out in this article? (Does this paper have a significant number of citations? Is the author a well-respected expert in the field of fusion energy?) Finally, assuming positive answers to these questions, the language and NPOV are so poor that they would have to be cleaned up before going live. --Art Carlson 09:16, 15 March 2007 (UTC)

Sorry. I messed up that last edit summary. I wanted to say that Wikipedia doesn't care about aneutronic fusion one way or the other. What Wikipedia wants is well-written, informative articles, based on reliable and verifiable sources, from a neutral point-of-view. --Art Carlson 08:56, 20 March 2007 (UTC)

[edit] Edits from folks who aren't logged in and aren't really good with English

I've noticed that there are edits here that are probably very interesting but aren't written well enough to keep. Unfortunately, that seems to be making alot of work for Art. I would ask that whoever is doing those edits to seek a friend who speaks better English or to put your contributions on the Japanese wikipedia. Here are the IP addresses that have been loading down this article with hard to understand edits:

210.249.100.16 
211.129.222.223
Retrieved from "http://en.wikipedia.org../../../a/n/e/Talk%7EAneutronic_fusion_4a7e.html"