Overcoming the obstacles to achieving unity- removal of He3 nuclei.

[Dan Tibbets]

Some points: If you are at 1 micron pressure you have ~ 10 ^13 particles per cubic centimeter. If you are producing 2 billion fusions per second that would be ~ 10 ^9 charged fusion particles produced per second (the neutrons leave the system) distributed over the volume of the vessel. If the vessel is 1 liter (1000 cc) then you would have to run the fusor for ~10^ 5 seconds to build up the fusion products to 1% of the fuel particles density. That is ~ 30 hours (and it ignores continuous vacuum pumping and fuel resupply)!
Actually the charged fusion particles (He3, Tritium, and protons) are at high energy and would hit the walls at high speed and possibly embed in the walls. The much greater problem would be all of the metal ions sputtered off of the walls from these impacts and polluting the plasma.

In order to avoid neutrals, you need a vacuum level better than that generally used in glow discharge fusors. My impression is that the neutrals become a minority (provided ions are provided by some other means) in the system at around 1 to 0.1 Microns. since a glow discharge cannot be maintained at these levels, you have to have to provide the ions with ion guns. This is along the lines of what Hirsch did and what U. Wisconsin is doing now in one of their experiments (looks like it is a duplicate/ extension of what Hirsch did). And that is why some here are working with ion guns or other means to produce ions.

As mentioned this does nothing about electron losses, or ion losses to the grid and walls, so breakeven is impossible. But a lot of neutrons could be produced.
To eliminate (control) both the electron losses and the ion losses and avoid the compromising effects of neutrals) has been the holly grail of fusion. Tokamaks and other magnetic confinement approaches tries this with bruit force magnetic effects. Bussard's Polywell concept attempts to 'cheat' by using both magnetic and electrostatic (electrodynamic) effects, while decoupling the competing harmful interactions.

An Elmore Tuck Watson (ETW) design in which the grids are magnetically shielded might reach breakeven, but at sizes which would far exceed those of Tokamaks. The Polywell boosts the basic ETW approach through a density enhancing process which is called a Wiffle Ball effect. This allows much smaller breakeven sizes (if multiple potential problems are overcome). The best place to pursue Polywell considerations is on the TalkPolywell.Org forum. Other approaches which have some potential includes General Fusion's approach, FRC approaches, and DPF approaches. Then there are all the variations on Tokamaks, Spheromaks, etc.

D Tibbets

[Carl Willis]

>That IS the article from which the quote came, Carl.

Yup, and it seems that you didn't process all of the information in the article. Again, the branches of the DD reaction and the reaction products are all represented in the table provided in that article. I really don't want this thread to devolve into a literacy project...

[Linda Haile]

Thanks Dan, for a very enlightening post.

It certainly puts a lot of things into perspective without resorting to (to me) incomprehensible mathematics.

We have our own ideas about eliminating neutrals, but I'm not yet ready to discuss these (We want to carry out some experiments first to test our theory).

We did read all the polywell stuff before we discovered this site but I think that route is not really feasible for amateurs.

We are planning to use ion guns in order to produce a high percentage of monatomic ions as has been demonstrated by Doug and his team and it is interesting to note that most of the fusion products will remove themselves from the chamber, heating up the chamber walls.

If the problem is then to remove the sputtered products from the chamber, this will be the next thing to address. It should be easier than removing the products of fusion as they will be much heavier, but I'll leave that til later.

The next step will be to test our theory regarding the elimination of neutrals from the fuel within the chamber, or rather, to get the fusor working and then to try to prevent the formation of neutrals, and see if it results in a significant improvement in efficiency.

Once again, many thanks for your comments.

[Linda Haile]

I didn't really understand the tables Carl. I'm not a mathematician as I stated previously.

[Carl Willis]

Being a "mathematician" or not is beside the point. The notation in Wikipedia's table of reactions is just standard notation for describing nuclear reactions. You may learn about this notation on Wikipedia:

http://en.wikipedia.org/wiki/Nuclear_reaction

If you don't trust Wikipedia, you may learn about this notation from Hyperphysics:

http://hyperphysics.phy-astr.gsu.edu/hb ... ea.html#c1

An introductory physics textbook will also explain nuclear reaction notation.

Using the Google will also help explain nuclear reaction notation.

Even asking about the troublesome notation here directly would also have been better than lamenting the purported untrustworthiness of Wikipedia, but marginally so, because good solid resources surround you on this issue. Please try to be a self-directed learner...

-Carl

[Linda Haile]

Carl, not being a mathematician, I was searching the text.

I generally find the best way to undertake research of any kind is to use google to locate articles that may be relevant and then to use the 'find on page' tool in the toolbar.

In this instance google took me to the Wikipedia article on fusion and the 'find on page' tool first located a couple of references to D-T fusion and it's products, before locating the D-D fusion products that I previously quoted. I then searched the rest of the article but found nothing else of relevance.

In this case Wikipedia only described 50% of the products.

Wikipedia is an online encyclopedia renowned for using layman's terms that any idiot can understand but in this case only gave half an answer.

I contend that, in this instance, Wikipedia was unreliable.

My method of searching is very efficient, it found Wikipedia's answer to my query in a matter of minutes. The problem was that the text was incomplete. Had I not trusted Wikipedia and searched for confirmation elsewhere Richard would probably not have had to correct me.

In future I will not trust Wikipedia and hopefully will not make this type of mistake again.

[Carl Willis]

>In future I will not trust Wikipedia and hopefully will not make this type of mistake again.

Again, what an utterly bizarre conclusion. Whether or not you read Wikipedia is your own business, but trying to blame it for your own lack of comprehension on the matter of present concern is not gonna fly. The article's table AND text both mention the "two branches" of DD fusion, in standard notation and plain English, respectively. So as I feared, this has become a thread about reading comprehension rather than amateur nuclear fusion.

The snippet you selectively read (from the section on pyroelectric fusion) was this:

>At these energy levels, two deuterium nuclei can fuse together to produce a helium-3 nucleus, a 2.45 MeV neutron and bremsstrahlung. Although it makes a useful neutron generator, the apparatus is not intended for power generation

Nothing is wrong with this statement. Saying a particular fusion apparatus can make He-3 and a neutron doesn't mean that other products don't occur. There is no error of omission because completeness was not claimed and probably wasn't intended (the author mentioned use as a neutron generator, for which the other DD branch is uninvolved). And again, as mentioned, the rest of the article dutifully mentions both DD branches multiple times if you bothered to actually, you know, read.

As I understand it, your rationale for badmouthing Wikipedia's article and the site in general hinges on your selective and illogical reading of a snippet located using the browser "find" feature, a snippet that happens to be accurate, a snippet whose parent article happens to contain the information YOU missed, for whatever reason. Sorry, but your smear of Wikipedia is pathetic.

-Carl

[Steven Sesselmann]

Lyn,

You probably already had more answers to your question than you ever wanted, but one more won't make a difference..

As already expanded above, both 3He and T would not be a problem if they ended up in the mix, but the problem is they don't.

In a nuclear fusion reaction the neutron/proton and the 3He/T are ejected in opposite directions, conservation of momentum dictates this, as a result the 3He or T are ejected at around 0.8 to 1.0 Mev, which is far more energy than what the electrostatic energy well can contain, so the result is that these particles will hit the shell of your fusor and embed themselves in the steel wall. At this energy they penetrate up to 1 ľm into the steel. See modeling done by John Futter here;

viewtopic.php?f=14&t=6824#p42507

...and as Dan DT says, the end result, is likely a chamber polluted with metal ions.

However, since you seem to enjoy armchair physics, maybe you could work out a way to direct these fast charged fusion products (3He, T, p) through a solenoid, and use the electrical energy to power your grid...

Food for thought

Steven

[Linda Haile]

Thanks for your comments Steven.

I'm familiar with the power generation theory that you mention, Tom Ligon has gone into it in detail in his articles, however, no-one has yet been able to control the direction of the fusion products which is a pre-requisite for this theory to be workable.

A more practical form of energy extraction, if any-one ever achieves unity would be as heat from the shell, as they plan to do at ITER, etc.

The design I'm toying with will actually have a cylindrical ceramic shell, possibly with metal end plates (as do a lot of commercial plasma processing equipment). This design was partly inspired by Chris Bradley's crimzon donut experiment. (I believe you may have proposed a similar method of confinement using a glass tube in one of your theoretical designs.

My design is also inspired by Doug's cylindrical grid device.

The device I'm planning to build will use both CCP and ICP in an attempt to eliminate neutrals from the chamber. It is this that I am working on at the moment, the theory surrounding combining the two types of plasma coupling, and whether or not a synchronized pulsed setup is feasible.

Having now established that the main contaminants will be sputtered ceramic the actual products of fusion are pretty irrelevant at this point in time.

This forum has been invaluable, I'm able to draw on aspects of Doug's work, Chris's work and some aspects of the Star fusor as well in an attempt to eliminate neutrals from the chamber.

[DaveC]

Lyn -

The principal obstacle to achieving unity is NOT how to remove heat from the shell, or the presence of neutrals, or the sputtered metals from the inner grid and the shell....

Simply put ....it is that the fusion process (in the "fusors", under discussion on this board, and elsewhere) .... is very, very, very, very, unlikely to happen!

For all the deuterons slung at each other in these low pressure gas filled chambers, barely 1 in a billion produce a fusion event.

Let's do the math:

At a current of 50 mA (at this point, we don't care what the voltage is....) we are slinging 3.125 x10^17 ions at each other, every second! Quoting some of the very best results on this board, we get for this expenditure of effort, about 1 to 10 million neutrons per second, at around 2.5 MeV energy for each one.

Using the highest fusion numbers, this amounts to an average of one fusion event per 10 Billion attempts.

The energy involved in slinging these puppies together at about 50 kV, and 50 mA is about 2500 watts....The energy available to be recovered from the neutrons produced is about 4 microwatts. (there's about the same amount available also from the protons) You can get more energy than this by shuffling you feet across the carpet on a dry day.

Okay.... this topic has been discussed....countless times.... and the same conclusion is reached....

So.my advice is, rather than generate this long and nearly completely unproductive thread, do the foillowing:

(1) Read ALL the contributions on the topic first, beginning with the earliest dates you can get.....then
(2) Discuss it among yourselves, and see if you actually get the point. (It's clear to me that you do not... at this time.)
(3) Then..... carefully frame a soundly based question on something specific in the area of the things still unclear, and submit that for discussion.

Doing this you will get a lot more support, and most of us who have answered these queries forty eleven times, will be sooooo appreciative...That way, we'll be moving into new(er) territory. That's progress.... Good stuff.

The closing comments are not meant to offend, but to guide, as I also share Carl's and other member's frustrations on these so-oft repeated topics.

Dave Cooper

[Linda Haile]

Dave, It has already been agreed by Carl and others that if all collisions were fast on fast ie no neutrals in the chamber, that rate of fusion is a function of current squared.

I appreciate that removal of by-products is not an issue, and that I was mistaken in that respect.

I appreciate that there are also other factors that come into play.

If the concensus is that, once neutrals are removed from the equation, that fusion rate is a function of current squared then the maths says that unity is possible.

I'm now working on 'half baked idea number six' (the first five would have resulted in the inner grid being vaporized) and am planning to build a device to test this theory.

This device will not eliminate all neutrals but should eliminate the majority.

I appreciate that you are trying to help, but you are the first to suggest that fewer neutrals will not increase fusion rates and you also give no reason why you believe this to be the case.

I appreciate that the title of this thread is no longer relevant to the content, and I've started another on the subject of neutrals

[walter_b_marvin]

I think this environment can never quite be clean. The real problem may be the density of the plasma is too low to get a reasonible rate. I don't think turning up the juice is the asnwer either, I think that at some point the plasma density will self limit. There may be one ray of hope; think outside the box. Nature provides an example in that there is a catalysed fusion reaction that occurs in the interior of some stars. There is also a "muon catalyzed" fusion reaction that is sometimes tauted as the "Cold Fusion" mechanisim. Our own sun may use partial quantum "tunneling" effects to achieve fusion. Could it be that a fusor, with the correct mixure of gasses and precise conditions would achieve positive energy output?

[Linda Haile]

You are right, Walter.

Even if we can overcome grid losses and sputtering from the chamber walls, upping the voltage leads to Oppenheimer-Phillips effect, and upping the current leads to space charge issues.

The answer does lie with plasma density, but how?

Short of introducing muons into the mix (is it 80 MeV protons or 800MeV protons fired through a 10mm carbon target, I forget) or inventing a 'gravity field' to overcome space charge.....

Maybe eliminating the grids, increasing current and increasing the size of the device will get somewhere. Not my ideas, but ideas proposed by the late Dr Robert Bussard.

[walter_b_marvin]

ok so what about introducing muons into the mix?

1. Produce the muons by pion decay
2. produce the pions by striking alpha particles against carbon
3. produce the alpha particles by introducing helium into the mix
4. produce the carbon by introducing hydrocarbons into the mix


It can't be that simple could it? I'm sure the enegies are all wrong. But an ion gun into the fusor core might be a place to start

[Chris Bradley]

A number of comments I feel need commenting on. Some more in-depth reading on these topics should be of interest to you, and address these points.

walter_b_marvin wrote:
> The real problem may be the density of the plasma is too low to get a reasonible rate.
There is no 'plasma fusion' going on in a fusor. Fusion comes about from fast ions hitting stuff. One useful description often used is to say that it is 'locally hot, generally cold' fusion in a fusor. Forget plasma dynamics here.


> I don't think turning up the juice is the asnwer either, I think that at some point the plasma [sic - as above] density will self limit.
It does. Do a search and a read. No need for guess work on this point, it is done already, here.


> There may be one ray of hope; think outside the box. Nature provides an example in that there is a catalysed fusion reaction that occurs in the interior of some stars.
There's no evidence of any reactions to my knowledge, other than regular, one-and-only quantum tunneling fusions in the sun.


> There is also a "muon catalyzed" fusion reaction that is sometimes tauted as the "Cold Fusion" mechanisim.
No. Muon catalysed fusion is a strong and active area of proven research. The problem is that it takes more energy to make the muon than the number of reactions it can catalyse in its short life. Cold fusion is something quite different. It's a shame this genuine and repeatable phenomenon keeps getting confused by public ignorance with cold fusion that is, at best, very poorly understood, if it exists at all.


> Our own sun may use partial quantum "tunneling" effects to achieve fusion.
As above. The sun's fusion is the same quantum-tunneling mechanism as any other (*heavy caveats here - H+H fusion is mediated by the weak force and is very gossamer-thin and ethereal in fusion terms. Next up in reactivity, by ~12 orders of magnitude, are electromagnetically mediated reactions like D+D->4He, then strong mediated reaction that are some ~4 orders of mag more).


> Could it be that a fusor, with the correct mixure of gasses and precise conditions would achieve positive energy output?
No. Not with two-electrodes and DC current.

[Linda Haile]

Walter, firstly protons are hydrogen nuclei, not alpha particles (helium nuclei)

Secondly, pions are produced by firing very high energy protons through a 10mm piece of carbon in an ultra high vacuum and only 10%, if I remember correctly, spall pions, which decay into muons. The rest go straight through.

The energies required to run a synchotron would, I assume, be greater than any energy produced by muon catalyzed fusion. (I won't attempt the maths, although each muon would theoretically be able to catalyze many many fusion events before it decays, something like a few tens of nanoseconds if I remember correctly)

[walter_b_marvin]

1) I appreciate a good review
2) Many of my comments were qualitative, not quantative
3) Ok muon and cold fusion as envisioned as the original "Cold Fusion" investigation may be different things. This is mostly a semantic difference. Learn from Beck. Get some charity
4) Collision probality and "Density" are for practical purposes the same thing. This is basically a semanic difference.
5r) I am obviously not a fusion expert. I was refering to the FACT that our sun does a very slow burn. If I got some facts wrong I appolize, I was making just off the cuff comments, not preparing a paper for a scientific journal. What I am is a damn good systems designer, with a BS in physics. I will learn.
6) I did not propose two electrodes and DC only. I think I also mentioned an ion gun as a starting place
7) If the commentor does not open his mind to possibilities I agree he never will achieve fusion. That doesn't mean others might not. I think the commentor is trying to prove a negative by induction. Doesn't work. Edison (yep he was no Tesla) worked through 1000s of light bulb filliaments.
8) The commentor did not actually answer my question. What about muon injection into a fusor?

[Chris Bradley]

walter_b_marvin wrote:
> 1) I appreciate a good review
> 2) Many of my comments were qualitative, not quantative
Don't be disheartened. I am trying to encouraging some reading and self-directed learning. If I thought you didn't care, I wouldn't bother replying.


> 3) Ok muon and cold fusion as envisioned as the original "Cold Fusion" investigation may be different things. This is mostly a semantic difference. Learn from Beck. Get some charity
No semantics here, there is a clear difference. Muon fusion never came under the collective term 'cold fusion' to my knowledge, except perhaps in occasional misinformed articles in the popular media. On charity, it looks like my capacity for charity is like your background reading; a bit thin.


> 4) Collision probality and "Density" are for practical purposes the same thing. This is basically a semanic difference.
Not really. Please state the density of a proton. If you have two protons heading towards each other, how would you go about deriving their probability of fusion from their density...?


> 5r) I am obviously not a fusion expert. I was refering to the FACT that our sun does a very slow burn. If I got some facts wrong I appolize, I was making just off the cuff comments, not preparing a paper for a scientific journal. What I am is a damn good systems designer, with a BS in physics. I will learn.
No one here claims to be a fusion expert, but some may claim that they have done a little reading before posting. I'm glad that you are a damn good system designer, but you said that there is a catalysed reaction in the Sun. I don't see this falling into the 'off the cuff' category of comments, but maybe this is system designer terminology.


> 6) I did not propose two electrodes and DC only. I think I also mentioned an ion gun as a starting place
You asked "could a fusor..&c." and a fusor is a two electrode DC device. You can add an ion gun if you like, and my answer is still 'no', and it is for reasons well-described and collated in a recent FAQ that Richard Hull went to the trouble of preparing for you to read.


> 7) If the commentor does not open his mind to possibilities I agree he never will achieve fusion. That doesn't mean others might not. I think the commentor is trying to prove a negative by induction. Doesn't work. Edison (yep he was no Tesla) worked through 1000s of light bulb filliaments.
The commentator has one of the openest minds you can imagine. The commentator has not suggested he will or will not achieve fusion so is not a matter you can agree, or otherwise, on. What has been said that the commentator has not opened his mind to?


> 8) The commentor did not actually answer my question. What about muon injection into a fusor?
The commentator said that this is a well-researched area and from such a comment it should be clear to the questioner that he would find a 'target-rich' search outcome on the internet, if the questioner took on board the suggestion of some reading and self-learning. If the questioner feels unable to do such self-learning because systems designers tends not to have much practice in self-learning, then the commentator is happy to help out by mentioning that muon induced fusion is done at high densites (liquid/solid conditions) and close to absolute zero conditions. The commentator would care to point out that if there was any benefit to muon induced fusion in low density media, such as may be found in an evacuated fusor, then the commentator would have expected muon catalysed researchers to have conducted such experiments but haven't.

[Linda Haile]

Walter, I think (again, if I remember correctly) that the current muon catalyzed fusion experiments use liquid deuterium/tritium.

Your comments about introducing hydrocarbons into a fusor and bombarding with protons will require a synchotron to accelerate the protons to the required energy levels and then it will be very 'hit or miss'.

firing the protons through a carbon 'window' in the fusor would probably be the most feasible solution, but this will still use more energy than can ever be produced.

You may be interested in this:

http://www.rikenresearch.riken.jp/eng/frontline/5976

[walter_b_marvin]

I also read that cryogenic tempetures were used in muon induced fusion. but so far I have no explaination why this was so. If fact, I beleive that muons were first discovered in cosmic ray transactions, at room tempeture. I agree that some kind of injection would probably be required to produce the muons, and this is a starting point for more careful calculations. My idea was to use the fusor itself to produce the alpha particles and thense pions and thense muons. I also stated that the energies were probably wrong. 1ev is roughly 1200 K. the Gev range of reactions would therefore require a tempeture in the 10 exp 12 range or 10,000 times the 10 exp 8 fusor tempeture ranges. Hence an high energy alpha particle injector would be required, even if the carbon were already in the fusor core. Am I wrong about this?

[Carl Willis]

Muon catalyzed fusion has been advocated on this board again, and again, and again, and again, and again, and again, and again. And again today.

Searching on the word "muon" will uncover all those old threads, in which a more-than-sufficient case is made that the concept is far outside the purview of amateur fusion. (A search will not bring up a few choice threads about muons that were removed for trollsome content.) As I see it, the muon issue will become relevant and tolerated on this forum whenever (if ever!) someone makes the connection between particles of a hundred MeV rest mass energy and what can be accomplished within the constraints of an amateur-science avocation. The day for this may come, however unlikely. But until it does, please do not rehash the subject here.

-Carl

[walter_b_marvin]

This was more conjecture than anything else Producing muons does appear to be a formidble challange

[Mike Beauford]

Hi Walter,

The key sentence Carl stated was "the connection between particles of a hundred MeV rest mass energy and what can be accomplished within the constraints of an amateur-science avocation."

The issue here Walter is it takes a massive amount of energy to create muon's in the lab, think LHC energies to create them. You will not create muons in a home experiment. If you can somehow harness the muons that naturally occur with cosmic rays hitting the earth go for it, but again, this is a dead end.

Mike Beauford

[walter_b_marvin]

I had a thought about natural collection of cosmic rays but to get a flux of 10x6 per sec requires an area 8 football fields in size even at 100% effeciency

[Dan Tibbets]

Indeed, the energy required to produce Muons is difficult to recover by catalyzed fusion within the brief lifetime of the muon.
Wikipedia describes muon catalyzed fusion in a cryogenic bath of deuterium molecules. Here the moun replaces one of the electrons in a molecule, and because of its large mass it orbits much closer to the nucleus. This shields the nucleus from the approaching nucleus, so that coulomb repulsion is delayed until the nuclei approach closer than this small muon orbital distance. This is apparently close enough that the strong nuclear force has a much greater chance of gaining ascendancy over coulomb repulsion, and fusion occurs with a high probability, even in this very cold fluid. In a hot plasma, the electrons are dissociated from the nucleus, so they do not spend much time near a nucleus, compared to an orbiting electron (or orbiting muon). I presume a muon would act similarly, so much of the shielding may be dampened (What is the ionization potential of a hydrogen-muon atom anyway?).
I presume that the muon catalyzed fusion rate in the dense cold liquid, even at low temperatures, is much greater than in a hot and much less dense plasma, so that you would get less fusion energy out over the lifetime of any one muon- the energy balance would be worse. I've not seen any muon scheme that does not incorporate this cold dense atomic fluid. Another issue is the muon source. Cosmic ray derived muons are completely inadiquate. Muons generated in an atom smasher and shot into the fusor could be more dense, but how dense. How much atom smashed products are delivered by large colliders. A few watts? a few thousands of watts? The inefficiencies of the atom smashers would be a large hurdle to over come. You get a few watts worth of muons in order to drive a few thousands of watts of fusion power (probably an optimistic guess). So at the expense of a few hundred millon dollers for the atom smasher, a few megawatts (at least) of power delivered to the atom smasher, you get a net Q fusion reaction (considering the reactor itself), but total system efficiency would still be far short of breakeven.

Dan Tibbets