Fourth Generation Nuclear Weapons

[James Essig]

Hi GammaScanner;

I was sort of thinking gamma rays produced with an energy of rough order of magnitude of the temperature of the plasma in the form of black body radiation. The temperature of the plasma with nucleon/proton/other charged particles of about 10 EXP 15 K might very briefly radiate gamma rays on the order of 10 EXP 12 to 10 EXP 13 eV extrapolated from 1million to 10 million eV gamma rays from the initial plasma produced in the nanoseconds after the fusion sequence of a thermonuclear device is complete. A more realistic model might be the gamma ray energies that exist within the fission component just after the chain reaction has effectively ended. The maximum temperature of the fission reaction is about 100 million K at fission completion. For the fusion sequence, the maximum temperature reaches about 300 million to 400 million K although these temperatures are probably at locations well within the fusion stage where pressures and temperatures can be compounded by the compressive effects of the overlayers of fusioning material. At gamma ray energies approaching 1 TeV, interaction with quarks composing the nucleons no doubt becomes important.

Collisions of gamma rays among nucleons might produce some of the desired gamma rays through compton scattering, charged particle collisions might produce additional gamma rays, and other exotic reactions that produce extremely hard gamma rays such as those that occur in 1 TeV accellerators and soon, the 14 TeV accellator at the upgraded CERN may be gamma ray components. Although I would say that some way of producing a high enough plasma density would be required to allow for gamma ray interactions before the gamma rays would escape for compton scattering to work at these extreme energies.

Thanks for the insights and questions!

Regards;

Jim

 

[vanesch]

Hi GammaScanner;

I was sort of thinking gamma rays produced with an energy of rough order of magnitude of the temperature of the plasma in the form of black body radiation. The temperature of the plasma with nucleon/proton/other charged particles of about 10 EXP 15 K might very briefly radiate gamma rays on the order of 10 EXP 12 to 10 EXP 13 eV extrapolated from 1million to 10 million eV gamma rays from the initial plasma produced in the nanoseconds after the fusion sequence of a thermonuclear device is complete.

I honestly doubt that you could get to TeV energies with nuclear explosions, even with very special ones. After all, individual processes start out at the 200 MeV range (fission energy, or of the order of 14 MeV fusion energy), and thermodynamics will normally make it such that this energy gets distributed over more and more degrees of freedom.

 

[James Essig]

Hi vanesch;

Thanks very much for the insights and comments.

It will be interesting to see what sort of particles and interactions can and will occur when the upgraded Large Hadron Collider goes on line at CERN this May. Perhaps more particles and decay sequences will be discovered adding to the great number of Feyman diagrams for which we would have discovered real particle interaction sequences thereby allowing even more degrees of freedom thus really putting the kobash on the concept that TeV energies could be generated by any realistically sized nuclear device.

Regards;

Jim

 

[James Essig]

Cluster Nuclear Devices

Hi Folks;

I once, and I believe only once, read of the concept of cluster bomblet nuclear munitions back in the very late 1970s in a public dailly news paper. I believe it was either the Washington Post or some other newspaper of the Washington D.C. metro area.

I have often wondered how effective such a device could be, say perhaps on the battlefield, or for use in a counter strike on populated areas if the U.S. were to suffer a very unfortunate first strike.

My idea is that the device could contain 100 or perhaps even 1,000 bomblets each of the mass of the "Davy Crockett" warhead which as a very low mass nuclear device with a yield of between 10 and 20 tons of TNT, as small of a yield for which nuclear devices have been produced. I hear that 2,100 of the "Davy Crockett" devices were produced but that they were retired in the early 1970s.

The device reportedly would produce a near instantly fatal dose or ionizing radiation at a range of about 500 feet and a most probably lethal dose at a range of 1/4 mile. I can imagine if the yield were to be boosted to 1 kiloton in the form of a neutron bomb, a similarly compact device would have great deterent value in the form of a neutron cluster bomb.

A fourth generation nuclear device utilizing pure fusion bomblets within a cluster bomb might have even greater deterent value. If a kilogram of hydrogen were to undergo complete nuclear fusion, then the resulting yield would be about 225 Kt/Kg. Now obviously, a pure fusion bomb would probably not have all of its fusion fuel fused simply because some of it would be blasted away by the explosion before it would fuse. But my God, could you imagine a pure fusion cluster bomb utilizing 100 or even 1,000 225 kiloton yield bomblets! Talk about deterence!

Just a thought.

Regards;

Jim

 

[JeffKoch]

Keep in mind that anyone really familiar with this stuff can't talk about it on forums, much less publish papers about new "fourth generation" concepts in apparently unrefereed unclassified online journals. I'd take any information stated in this article with many grains of salt.

 

[James Essig]

Hi Folks;

Bear in mind that the same laws of physics that the folks at LLNL and other nuclear weapons R&D labs are bound by are the same laws that all other physiciists are bound by. The U.S. government is not bound by Divine providence to have an absolute monopoly on all possible nuclear weapons designs that have not been realized. I am sure there are workable nuclear weapons configurations that have not been tested and perhaps not even thought about by the folks at LLNL and the like.

Some of the folks at the Relativistic Heavy Ion Collider and at the LHC at CERN, which is soon to be operational again, will no doubt want to look for additional nuclear forces aside from the strong nuclear force and the weak nuclear force. The existence of additional nuclear forces has been hinted at by experimental anomalies as we probe the nature of fundamental particle physics at ever greater energy levels. One can only speculate what nuclear devices might be capable for devices that would somehow involve the principles of the application of any yet to be discovered nuclear forces.

I personally think that this is a fine thread with lots of good comments being posted.

Regards;

Jim

 

[sanman]

Here's an idea that I posted in its own thread:

https://www.physicsforums.com/showthread.php?p=1763651#post1763651

What do you think of this? Could buckyballs be the answer?

 

[James Essig]

Hi Sanman;

The idea of using buckballs or other fullerines to contain compressed hydrogen, perhaps in a metallic state does seem to have good potential within the field of nuclear weapons design.

Any way in which hydrogen in its various isotopic forms can be produced in an ever more dense and stable manner potentially allows for more of the hydrogen isotopic fusion fuel to be fused instead of being blasted away by the fission primary stage. Note that the most exothermic fusion reactions convert about 0.7 percent of the reactants mass to energy. This allows 1 kilogram of this ideal fusion fuel to yield about 180 kilotons + when fully fused. Thus any process that allows more densely concentrated precursor fuel can potentially lead to higher mass specific yields for thermonuclear devices.

Thanks for asking.

Jim

 

[sanman]

Hi James,

Thanks for your response. My understand is however that nobody has found a way to synthesize these idealized these densely-hydrogen-filled buckyballs. I was wondering if quantum tunneling might be able to get hydrogen inside buckyballs. Since hydrogen is smaller and lighter than the buckyball, perhaps it could tunnel its way across the graphene shell, to get inside the buckyball.

Another idea I had was perhaps using an ultra-short (femtosecond/attosecond) pulse laser, to deform a local region on the buckyball's graphene mesh long enough for hydrogens to get inside.

Does anyone else have any speculations or conjectures on how metallic or ultra-dense hydrogen within the confinement of buckyballs could be achieved?

 

[sanman]

Another idea I had was to use the photon resonance with the buckyball to manipulate the surface plasmons and/or volume plasmons to help us get the hydrogen inside.

http://www-als.lbl.gov/als/science/sci_archive/103plasmon.html

Perhaps with the volume plasmon effect we could make the buckyball expand and contract enough, so that when its mesh is expanded we could get the hydrogen inside, and then when its mesh contracts it will compress the hydrogen.

Hmm, sort of like the pumping action of a heart, except without any primary inlet and outlet. All the gaps in the expanded mesh could act as inlets.

Later on, by introducing muons into the picture, then all bond orbital lengths could be made to contract even further -- not just the D-T bonds, but also the C-C bonds -- so that everything gets even more compressed.

 

[James Essig]

Hi sanman;

Those are some very interesting ideas. Another possible way to get the hydrogen, deuterium, and/or tritium inside is to beam it at the sample of carbon buckyballs or other fullerenes in a manner similar to ion beam deposition. For those of the Physics Forums readership who might not be familiar with ion beam deposition, it is a technique by which a relatively low energy ion beam is directed to a metal surface or alloy surface wherein it is desired to produce special surface characteristics within the surface layer of certain pieces of metal such as for very hard surfaced temperature and scratch resistant components of mechanical systems and the like.

Regarding the application of muons, in consideration of ultra dense forms of metallic hydrogen, one thing comes to mind, and that is muon catalyzed fusion. The ultra dense state of the hydrogen would allow a significantly reduced mean free path for the muons within the sample hydrogen thus potentially allowing more hydrogen nuclei to be fused via the muons acting as an intermediary between the hydrogen nuclei. Once a sample of such densely packed hydrogen would undergo muon catalyzed fusion, perhaps the fusion process could boot-strap itself with the energy released by the muon catalyzed fusion reactions thus resulting in a thermonuclear explosion.

I am not sure, however, how small muon production apparatus have become. One would not want to build a substantially large particle accelerator just to initiate a modest size thermonuclear device's explosion. However, your idea of using muons to facilitate the filling of the buckyballs is intriguing.

Note, I am not sure if this posting went through so it may appear in duplicate form at least temporarilly. I have been having some software troubles as of late.

Thanks;

Jim

 

[sanman]

Hi Jim,

I totally agree with you - that's why I posted about the muons, because of their ability to catalyze the hydrogen fusions. I had posted about this a couple of months ago, on a separate thread:

https://www.physicsforums.com/showthread.php?t=226759

Here's a good refresher on muon-catalyzed fusion for everyone:

http://en.wikipedia.org/wiki/Muon-catalyzed_fusion

So to make a net energy profit, 600 fusions have to be catalyzed per muon before it expires. Right now, the best that's been demonstrated is 150, so that has to be quadrupled at least.

The density of frozen hydrogen is cited at 0.088g/cm^3:
http://hyperphysics.phy-astr.gsu.edu/Hbase/pertab/h.html

The density of metallic hydrogen is cited at 0.4g/cm^3:
http://www.springerlink.com/content/h226824477441582/

Metallic hydrogen seems to offer a density ~5 times greater than frozen hydrogen, which I'd hope might be enough for net energy output above breakeven.

Another significant problem mentioned may be the "alpha-sticking", whereby the alpha-particle produced by the fusion reaction might snatch away the muon due to its double-positive charge. I'm hoping that within the confines of the metallic hydrogen and surrounding buckyball, the alpha particle might have more difficulty leaving, so its muon might be kept available.
The other problem, mentioned in that older thread, is that the main holdup in the fusion process is the time it takes to form the muonic bond between D-T (5 nanosecs). Again, I'm hoping that the metallic state with its shorter interatomic separation distances, would accelerate the bond formation process.

Another way to favor net energy output is to reduce the energy requirements of a muon production:

http://www.springerlink.com/content/r5370246874n605u/ The next question is, how many hydrogens can fit into a C60 buckyball, at near-metallic pressures?

If required, there are larger sizes of buckyball, including C540:

http://www.3dchem.com/moremolecules.asp?ID=218&othername=c540

Perhaps with a nested buckyball (buckyonion), you could afford even higher pressures and densities of hydrogen inside.

Comments?

 

[sanman]

Here's something recent on dtµ formation, which is the main bottleneck in the muon-catalyzed fusion process:

http://www.springerlink.com/content/923x12g703511t21/

 

[James Essig]

Hi sanman;

The idea of using buckyonions I think is really neat for potentially storing high density hydrogen or deuterium. Another possible nanoscale storage material for dense hydrogen is carbon nitride which may have a bulk modulus in some forms higher than that of even pure diamond. If the pressure and temperature of the fusing hydrogen was high enough for devices based on dense hydrogen fusion fuel stored within carbon fullerenes, perhaps the carbon buckyballs could undergo nuclear fusion also, i.e., carbon nuclear fusion.

Regarding reliable warheads which use benign, cheap, and safe fusionable materials, I wonder if anyone has seriously investigated a so called water bomb, Such a device might make an excellent latter generation nuclear weapon if not a good fourth generation nuclear weapons technology.

The idea here is that a very high mass specific yield fission or fission fusion device would be used to set of a fusion reaction within a much larger volume of pure ordinary water, or perhaps pure heavy water. The yield of such devices could be staggering but kept at a safe predeployed level, wherein, when it was time to deploy the device, the liquid water could be quickly and safely added to the device in a manner in which the detonation of the primary would fuse the oxygen and hydrogen in the water thus resulting in a device with extreme yield.

If a spherically symmetrically exploding primary device could not produce the requisite pressures and temperatures to ignite the water stage, then perhaps a focused or shaped charged style nuclear device could.

It occurred to me to mention that other cheap, safe, and non-volatile exothermically nuclear fusionable fuels could be used in the construction of adjustable yield or yield augmentable thermonuclear devices including but not limited to carbon, perhaps even carbon containing plastic materials such as solid polymers, Nylon, Kevlar, and the like. Such high strength materials might somehow be utilized for their high elastic modulus to momentarily, at least on the scale of nanoseconds, provide mechanical resistance to the intense energy blast from the devices primary for purposes of allowing a super high pressure and temperature wave to develop within the carbonaceous fusion fuel in order to initiate a self propagating fusion wave front to travel thru the fussile material. Note that carbon is a good absorber of certain forms of ionizing radiation on the energy scale of nuclear reactions and has utility in modern nuclear fission reactors as a neutron flux moderator.

Although white dwarf stars as the dead remnant of stars with a mass of below about 1.4 times that of the sun are much more dense than ordinary matter at STP, in fact about a million times as dense, they can and do occasionally under go supernova which result in the complete fusioning of the entire star in a fraction of a second. So in a sense, carbon detonation fusion devices already exist in the form of naturally occurring solar mass range bodies.

Now the temperatures and pressures required to initiate a carbon fusion reaction are likely to need to be much higher, in fact they are higher, than that required for the initiation of traditional fussile materials in nuclear devices such as Lithium Dueteride. As a result, a highly optimized mass specific energy dense primary may be required, perhaps even a shaped charge type primary might be required to set off the carbonaceous or other higher atomic number fusion fuel. The use of these exotic fuels would probably only make sense for devices that have extremely high yield and thus which have a relatively large mass wherein cheap fusion fuel is desired.

Thanks;

Jim

 

[vanesch]

I have the impression there's a lot of talking here without any sound ground. Now, of course, apart from some rudimentary knowledge, I'm of course no nuclear weapon expert - and has been said here, anyone who is will not put his knowledge to display on a public forum.

However, it seems to me that always the same elementary errors are made. It is not because certain mechanisms seem 'violent' that they also correspond to high particle energies. I think that most of the mechanisms proposed here, where one wants to take into account any solid material strength, miss the point that solid materials obtain their strength from eV level binding energies, not something that can contain KeV and MeV energy particles. What nuclear explosions is concerned, any material can be seen in good approximation as a fluid.

As to metallic hydrogen, the gas giants are full of it, under much higher pressure, and with much higher inertial confinement than can be achieved in a small box, and of course there's sometimes the occasional muon which comes by (be it by the rare capture of a muon neutrino), and they don't explode like monster thermonuclear bombs.

As to the 'water bomb', as there have been nuclear tests under water, clearly (happily!) there is no self-ignition of water. H-H fusion is much more difficult than D-T and D-D fusion, and H-H is still much easier than O-O fusion. You need a supernova to achieve that!

So please, a bit more realism in the discussion, and when things become hypothetical, please provide at least some numerical estimates for the claims.

 

[sanman]

hi Vanesch,

Well, I was then specifically mentioning the muon-catalyzed fusion to address those points, which you had also similarly made in the other thread.

But I'm not sure about what further research has been done into reducing the D-T formation time. I do think there has been research into attempting more efficient production of muon beams, to reduce energy cost and increase muon beam intensity.

The thing is that people want safe and abundant nuclear energy, but there aren't enough solutions forthcoming on how to provide it.

 

[James Essig]

Hi Folks;

Part of the reason why underwater tests of nuclear devices never set off ocean water in a fusion reaction might be due to the limited mass specific yield of the nuclear devices tested or perhaps the limited mass specific yield of spherically symmetrically exploding devices in general.

Perhaps, a shaped charge nuclear device that concentrates its explosive flux energy and pressure in a manner similar to that of a bazooka could do the job in setting off a water bomb. Note that shaped charged nuclear devices, according to some open literature on the subject, may be capable of concentrating their explosive flux energy as much as 6 orders of magnitude above that of a spherically symmetric explosion. If such high flux concentration is possible, I would not be surprised if water bombs are eventually produced.

An ordinary piece of TNT with a mass of a few kilograms detonated outside the hull of an M1Abrams tank will not phase the vehicle, a HESH round can indeed disable our best battle tanks as we have seen in the war in Iraq.

Regarding nuclear weapons researchers not posting nuclear weapons concepts on line, that is definitely true in all cases. However, these researchers are not guaranteed to have a monopoly on nuclear weapons designs or concepts any more than the US is endowed by God to always be the most powerful country on Earth. New ideas come from all places and times and new paradigms are rarely predicted in advance.

Thanks;

Jim

 

[vanesch]

Well, I was then specifically mentioning the muon-catalyzed fusion to address those points, which you had also similarly made in the other thread.

Muon-catalyzed fusion works - is demonstrated without doubt, and is also understood, for D-D, H-D, and D-T. I don't think it has been shown for H-H. But you still have to make the muons! http://en.wikipedia.org/wiki/Muon-catalyzed_fusion

But I'm not sure about what further research has been done into reducing the D-T formation time. I do think there has been research into attempting more efficient production of muon beams, to reduce energy cost and increase muon beam intensity.

As muons don't exist in abundant quantity on earth, and are unstable http://en.wikipedia.org/wiki/Muon with a life time of 2 microseconds there are not many options. Given that its mass is 105 MeV / c^2, you will need a process that spends *at least* 105 MeV per muon, that will live for about 2 microseconds. The only known way to produce muons is to have a beam of protons slam into some matter, produce a hadronic shower containing also a lot of pion particles of which there are 3 kinds: pi-+, pi-- and pi-0. pi-- decay preferentially into muons (pi+ into anti-muons), which can then be extracted by a thick iron wall which will stop all gamma and other particles, and a magnetic selection which will take out the muons and send the anti-muons elsewhere.
Not really something that you can put in a tabletop device or in a bomb.

The thing is that people want safe and abundant nuclear energy, but there aren't enough solutions forthcoming on how to provide it.

You seem to forget that you were talking about *weapons* with sci-fi properties.

I think if we rely on nuclear power, then there is more than enough of it, in relatively safe ways, for everybody. Thermal fission can provide enough in the coming decades, fast breeder fission can provide enough in the coming centuries, and a few centuries should allow us harness fusion in one way or another. Even D-T fusion is enough for millions of years.

Although it is true that nuclear power has a (tiny) risk to it, and is not 100% clean, it is more than good enough, compared to the *realistic* alternatives that we have.

 

[vanesch]

may be capable of concentrating their explosive flux energy as much as 6 orders of magnitude above that of a spherically symmetric explosion. If such high flux concentration is possible

I would like to see something about that - I have a hard time believing it, and it depends what quantity is "6 orders of magnitude" larger. If you simply think of some radiant energy or whatever, that would mean that instead of sending out a flux in 4 pi (spherically symmetric), this same flux is now sent out in a beam with angular divergence 4 pi / 10^6 ~ 10-5 sterrad, which means an angle of opening of about 0.003 rad, or 0.2 degrees. That's much much better directivity than a flashlight (around 10 degrees), even much better than a search light (about 5 degrees). Hell, that's even better than a laser pointer, which is around 0.01 rad !

 

[sanman]

accelerating D-μ-T formation

Hi Vanesch

I feel that the difference with having the hydrogen inside buckyballs is the geometry. Each buckyball would be able to shape or channel external forces to focus them on squeezing the hydrogen contained inside.

Similarly, muon-catalyzed fusion has achieved the highest energy return so far (~67% of breakeven), more than even the tokamaks, because the muon at 207 times the electron's mass can create a molecular bonding orbital between hydrogens that is 207 times closer. At this short distance, quantum tunneling causes the hydrogens to fuse within half a picosecond.
Even though the short-lived muon lasts only 2.2 microseconds before it expires, it can catalyze a couple of hundred fusions during that time.
So as with the buckyball, it's the close-up interaction that the muon is having with the hydrogens (or more accurately, D-T) which is helping to broker the fusion process.

http://en.wikipedia.org/wiki/Muon-catalyzed_fusion

It is only due to the slow formation time of the muonic D-T molecule (5 nanoseconds) which seems to be limiting the muon from catalyzing more fusions. If only some way could be found to speed up the formation of D-μ-T, then perhaps the process could exceed breakeven. Perhaps the buckyball might help in this regard, by squeezing the hydrogens closely enough that their separation distances are closer to that of the muonic bonding orbital distance, so as to make the formation of that muonic bonding orbital easier.

So with a quick calculation based on 12 H for every C (8%Wt hydrogen from the articles), there would be 720 hydrogens inside a C60 buckyball (60C*12H/1C=720H). From wikipedia the muon must be able to catalyze at least 600 fusions in order to achieve breakeven, which means we need at least 1200 atoms inside there.
That means we need to go to the next larger size of buckyball, C240, which should be able to contain at least the same 8% H by weight, if not more.
So 240C*12H/1C=2880H which is more than enough for possible achievement of breakeven.

In my mind, if the buckyball's compression can achieve metallic DT having interatomic distances closer to the muonic molecular bonding orbital length, then this would facilitate/accelerate the D-μ-T formation. If this can appreciably lower the 5nanosecond bottleneck in the fusion-catalysis process, then it could be well worth it.

Comments?

 

[James Essig]

Hi Vanesch;

The web based document that I recall reading the 6 orders of magnitude figure mentioned some disk-like shaped configuration of the nuclear reaction fuel wherein a proper detonation of the fuel along the disk's radial dimension might do the job. Perhaps the pressure within the superhot plasma being ejected from the central part of the disk can be greatly amplified and this along with any thermal electromagnetic emissions from this plasma jet with greatly increased pressure and temperature corresponds to the figure of 6 orders of magnitude.

Thanks;

Jim

 

[vanesch]

Hi Vanesch

I feel that the difference with having the hydrogen inside buckyballs is the geometry. Each buckyball would be able to shape or channel external forces to focus them on squeezing the hydrogen contained inside.

Similarly, muon-catalyzed fusion has achieved the highest energy return so far (~67% of breakeven), more than even the tokamaks, because the muon at 207 times the electron's mass can create a molecular bonding orbital between hydrogens that is 207 times closer.
At this short distance, quantum tunneling causes the hydrogens to fuse within half a picosecond.
Even though the short-lived muon lasts only 2.2 microseconds before it expires, it can catalyze a couple of hundred fusions during that time.
So as with the buckyball, it's the close-up interaction that the muon is having with the hydrogens (or more accurately, D-T) which is helping to broker the fusion process.

http://en.wikipedia.org/wiki/Muon-catalyzed_fusion

It is only due to the slow formation time of the muonic D-T molecule (5 nanoseconds) which seems to be limiting the muon from catalyzing more fusions. If only some way could be found to speed up the formation of D-μ-T, then perhaps the process could exceed breakeven. Perhaps the buckyball might help in this regard, by squeezing the hydrogens closely enough that their separation distances are closer to that of the muonic bonding orbital distance, so as to make the formation of that muonic bonding orbital easier.

So with a quick calculation based on 12 H for every C (8%Wt hydrogen from the articles), there would be 720 hydrogens inside a C60 buckyball (60C*12H/1C=720H). From wikipedia the muon must be able to catalyze at least 600 fusions in order to achieve breakeven, which means we need at least 1200 atoms inside there.
That means we need to go to the next larger size of buckyball, C240, which should be able to contain at least the same 8% H by weight, if not more.
So 240C*12H/1C=2880H which is more than enough for possible achievement of breakeven.

In my mind, if the buckyball's compression can achieve metallic DT having interatomic distances closer to the muonic molecular bonding orbital length, then this would facilitate/accelerate the D-μ-T formation. If this can appreciably lower the 5nanosecond bottleneck in the fusion-catalysis process, then it could be well worth it.

Comments?

I think you answered your own question. The muonic molecule is about 207 times smaller than the normal D-T molecule, so no way that a normal chemical set of bonds (like in buckyballs) is going to achieve such a compression. In fact, if it did, there would be no need for muons ! But it can't. It is as if you were trying to compress a massive iron ball 207 times by using a fisherman's net around it.

 

[vanesch]

The web based document that I recall reading the 6 orders of magnitude figure mentioned some disk-like shaped configuration of the nuclear reaction fuel wherein a proper detonation of the fuel along the disk's radial dimension might do the job. Perhaps the pressure within the superhot plasma being ejected from the central part of the disk can be greatly amplified and this along with any thermal electromagnetic emissions from this plasma jet with greatly increased pressure and temperature corresponds to the figure of 6 orders of magnitude.

That's no explanation at all, sorry. That could eventually explain a factor of 6 or so, but not a factor of one million. Again, saying that something has, because of directivity, a factor of 1000000 more "stuffiness" (energy, pressure, heat, whatever) than an isotropic thing, means that it must have a directivity with a divergence of 0.2 degrees: the narrowness of the beam of a laserpointer.

 

[sanman]

I think you answered your own question. The muonic molecule is about 207 times smaller than the normal D-T molecule, so no way that a normal chemical set of bonds (like in buckyballs) is going to achieve such a compression. In fact, if it did, there would be no need for muons ! But it can't. It is as if you were trying to compress a massive iron ball 207 times by using a fisherman's net around it.

I figured you would say that. I didn't say that the buckyball compression would achieve that scale of interatomic distance, I said that it would bring the interatomic distance closer to that of the muonic molecular orbital bond length - and every little bit helps. It remains to be seen what effect the metallic density and interatomic distance would have on the formation time of D-μ-T, but if it could even reduce the formation time by just 1 order of magnitude, then that could push things well past breakeven.

 

[James Essig]

Hi Folks;

Perhaps the 6 orders of magnitude of energy flux compression could work for the disk shaped supply of fusion fuel and that just inside and outside the volume of space of the original disk near its center, one could obtain the 6 orders of magnitude. Just because the 6 orders of magnitude could not exist within a long extended beam does not mean that it could not start out with such energy flux compression. The highly compressed energy flux might indeed start out that way and then quickly diverge in terms of blast direction angular spread. If the disk shaped configuration is not up to producing the 6 orders of magnitude energy flux compression, perhaps other configurations can and perhaps even surpass this value.

Thanks;

Jim

 

[Astronuc]

Muon-catalyzed fusion is an example of controlled thermonuclear reaction which is not the intent of nuclear weapons. As vanesch pointed out, it would not be feasible to introduce a muon source/generator within a nuclear weapon system. It might be worthwhile to split it off this discussion into a separate thread.

The buckeye ball idea is interesting but it faces some significant drawbacks. It seems suitable perhaps to the Inertial Confinement Systems, which already use cryogenic pellets, but then there is the matter of getting D-T or D-D into the buckeyeballs. One has to look at the conditions in which buckeyeballs are produced and compare that to solid/metallic hydrogen. Metallic hydrogen is formed under high compressive pressures.

A high-pressure phase of atomic hydrogen predicted theoretically to form at the center of Jupiter, was first produced in the laboratory by Weir et al. (1996), at a pressure of 93-180 GPa and temperature of 2200-400 K.

http://scienceworld.wolfram.com/physics/LiquidMetallicHydrogen.html

Liquid metallic hydrogen and the structure of brown dwarfs and giant planets
http://arxiv.org/abs/astro-ph/9703007

http://www.ncsa.uiuc.edu/News/Access/Stories/MetalHydrogen/Hydrogen.html

Are the process of buckeye ball formation and filling with hydrogen molecules compatible? What is the energy input and cost?

OK - assuming one obtains a collection of (DT)/(DD) buckeyeballs, how does one utilize them for fusion production? ICF? A beam of muons?

A unidirection beam of muons is problematic, to say the least, largely because of their very short lifetime.

The other factor is once some buckeyeballs experience fusion - the fusion plasma will blow them apart and collection/mass of buckeyeballs and the buckeyeballs themselves disperse.

 

[sanman]

Hi Astronuc, thanks for your response.

Well, note that the buckyball would contain mere hundreds of hydrogen atoms. How much energy could the fusion of these mere hundreds of atoms release, that they would not just blow apart but also disperse the surrounding buckyballs, before allowing other fusions to occur?

If these fusions are taking place among multiple buckyballs in a vicinity, then some will be dispersing buckyballs away, while others will see buckyballs dispersed towards them.

I'd imagine that the energy released by a fusion could help to cause adjacent atoms to fuse.

I'm not sure how fusion energy output is measured in muon-catalyzed fusion experiments. Is it measured in the form of a temperature rise in the frozen hydrogen medium? Or just in the form of gamma-ray and neutron-counter measurements?

 

[Astronuc]

Fusion reactions like the d+t reaction would be measured by the 14.1 MeV neutron.

http://en.wikipedia.org/wiki/Fullerene#Buckyballs - indicates the diameter from nucleus to nucleus of C₆₀ is about 0.7 nm or 7 Å. How much DT or DD could one put in a C₆₀ buckyball. I'm not sure this would be practical

It might be interesting to try boron bucky encasing H in order to try the p+B reaction. But I see this as an ICF target - perhaps, and not for magnetic confinement.

 

[James Essig]

Hi Sanman and Astronuc;

This has been an active and informative thread over the past day or so. Even if some of the ideas I have expressed over the past few days don't seem to hold water and turn out to be nonesense, I have still enjoyed the discussion.

Anything that advances the state of fusion physics or applied nuclear physics is cool to me. The National Ignition Facility should give us plenty of experimental data in nuclear fusion science and the interaction of particles within compressed plasma at temperatures on the order of 10 million K to 100 million K.

Thanks;

Jim

 

[sanman]

boron buckyballs, p+B

Fusion reactions like the d+t reaction would be measured by the 14.1 MeV neutron.

http://en.wikipedia.org/wiki/Fullerene#Buckyballs - indicates the diameter from nucleus to nucleus of C₆₀ is about 0.7 nm or 7 Å. How much DT or DD could one put in a C₆₀ buckyball. I'm not sure this would be practical

It might be interesting to try boron bucky encasing H in order to try the p+B reaction. But I see this as an ICF target - perhaps, and not for magnetic confinement.

Thanks for your response, Astronuc. It certainly gave me food for thought.

I still think that compression to metallic state would permit some slightly more rapid D-μ-T formation, which would benefit the muon-catalytic process. It still merits investigation even just for academic purposes.

But what you said about Boron buckyballs (B80) for the same type of setup, sounds very interesting. One might even suggest a Boron Nitride buckyball (B60N60, aka 'fulborene').

http://www.sciencedaily.com/releases/2007/04/070423111604.htm
http://www.mext.go.jp/english/news/1998/12/981206.htm
http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=APPLAB000075000001000061000001&idtype=cvips&gifs=yes

So based on what you've said, if any fusion energy produced inside the buckyball causes H to hit B with enough energy, then we get to benefit from the H+B fusion reaction as well, which however generates substantially lower power, but at least further exploits the encapsulating cage molecule:

http://en.wikipedia.org/wiki/Aneutronic_fusion#Technical_challenges

While the H+B fusion reaction is substantially lower in energy yield, perhaps this might be beneficial in terms of making the power release more manageable (ie. not dispersing all the surrounding buckyballs). It is also an aneutronic reaction, which could perhaps reduce the hazard of neutron radiation. Likewise, if the encapsulated atoms were all H instead of D & T, then H+H fusion reaction while producing 40 times less energy might similarly make the energy release more manageable and less catastrophic. Furthermore, is it possible that the positrons produced from the muon-catalyzed H+H fusion would anihilate with local H-bound electrons, thus increasing the opportunities for more rapid H-μ-H formation?

I am not sure what the cage strength of the B80 buckyball is, but fulborenes like B60N60 are supposed to have comparable strength to their carbon fullerene counterparts. Apparently the B-N bond is supposed to have a polar character which aids its strength when networked.

 

[vanesch]

Muon-catalyzed fusion is an example of controlled thermonuclear reaction which is not the intent of nuclear weapons. As vanesch pointed out, it would not be feasible to introduce a muon source/generator within a nuclear weapon system. It might be worthwhile to split it off.

Haha , using the SFSDS (Super Fast Strategic Delivery System) (TM). You initiate the detonation with a ground-based muon-source, and then you have 2 microseconds left to launch and deliver

 

[Astronuc]

I still think that compression to metallic state would permit some slightly more rapid D-μ-T formation, which would benefit the muon-catalytic process. It still merits investigation even just for academic purposes.

It would make for some interesting research.

But what you said about Boron buckyballs (B80) for the same type of setup, sounds very interesting. One might even suggest a Boron Nitride buckyball (B60N60, aka 'fulborene').

The drawback to BN is that the N competes with B for the p's.

So based on what you've said, if any fusion energy produced inside the buckyball causes H to hit B with enough energy, then we get to benefit from the H+B fusion reaction as well, which however generates substantially lower power, but at least further exploits the encapsulating cage molecule:

http://en.wikipedia.org/wiki/Aneutronic_fusion#Technical_challenges

I was musing about the p+¹¹B aneutronic reaction. If possible, aneutronic reactions are preferable with respect to direct energy conversion. The d+t fusion reaction is the easiest one to achieve, but one looses about 80% of the energy to the neutron, which then must be collected and the thermal energy extracted by more traditional means, as opposed to direct energy conversion. It also reduces or eliminates activation of the plasma containment structure.

Li+D (D + ⁶Li → 2 ⁴He + 22.4 MeV ) is an attractive fusion reaction from the energy/alpha particle and no neutrons.

While the H+B fusion reaction is substantially lower in energy yield, perhaps this might be beneficial in terms of making the power release more manageable (ie. not dispersing all the surrounding buckyballs). It is also an aneutronic reaction, which could perhaps reduce the hazard of neutron radiation. Likewise, if the encapsulated atoms were all H instead of D & T, then H+H fusion reaction while producing 40 times less energy might similarly make the energy release more manageable and less catastrophic. Furthermore, is it possible that the positrons produced from the muon-catalyzed H+H fusion would anihilate with local H-bound electrons, thus increasing the opportunities for more rapid H-μ-H formation?

p+p is not very efficient. That's the reaction that fuels the sun, and there the p-density is comparable to water at room temperature. The problem with fusion in metallic hydrogen is that as soon as fusion occurs, the metallic hydrogen heats and is no longer metallic hydrogen.

I'm not sure that positron annihilation occurs rapidly enough, nor frequently enough, to have a significant impact.

I am not sure what the cage strength of the B80 buckyball is, but fulborenes like B60N60 are supposed to have comparable strength to their carbon fullerene counterparts. Apparently the B-N bond is supposed to have a polar character which aids its strength when networked.

B80 research is still in its infancy - http://www.eurekalert.org/pub_releases/2007-04/ru-bbt042307.php

Haha , using the SFSDS (Super Fast Strategic Delivery System) (TM). You initiate the detonation with a ground-based muon-source, and then you have 2 microseconds left to launch and deliver

Would that be a 10¹⁵TW source?

 

[sanman]

It would make for some interesting research.

The drawback to BN is that the N competes with B for the p's.

I was musing about the p+¹¹B aneutronic reaction. If possible, aneutronic reactions are preferable with respect to direct energy conversion. The d+t fusion reaction is the easiest one to achieve, but one looses about 80% of the energy to the neutron, which then must be collected and the thermal energy extracted by more traditional means, as opposed to direct energy conversion. It also reduces or eliminates activation of the plasma containment structure.

Li+D (D + ⁶Li → 2 ⁴He + 22.4 MeV ) is an attractive fusion reaction from the energy/alpha particle and no neutrons.

What about a lithium-coated buckyball (Li12C60) then?

http://www.primidi.com/2006/07/26.html
http://www.greencarcongress.com/2006/07/researchers_des.html

I don't know what its cage strength is, though. Hopefully it would be comparable to C60.
They do mention it could store 13 Wt% of Hydrogen, but these appear to be H-bonded to the outside of the Li12C60 buckyball. Maybe these could supplement storage of hydrogen inside the buckyball as well.

So you could fire your muons at the Li12C60 buckyball, and if it catalyzed any fusions among the encapsulated D, then energy could be imparted to nearby D which might perhaps collide with the Li in the surrounding shell.

I've never heard of muon-catalyzed fusion being attempted with non-hydrogen reactants.
Could it work for Li+D directly? Could you just stuff LiD inside the buckyball and try to catalyze fusion on that?

B80 research is still in its infancy - http://www.eurekalert.org/pub_releases/2007-04/ru-bbt042307.php

Well, if you look at the structures of the B80 and Li12C60 buckyballs, then is there any way to make a buckyball out of Li and B?

 

[sanman]

Hmm, found this:

http://www.iop.org/EJ/abstract/0954-3899/16/2/017

http://www.iop.org/EJ/abstract/0954-3899/16/2/017"

D Harley et al 1990 J. Phys. G: Nucl. Part. Phys. 16 281-294

D Harley, B Muller and J Rafelski
Dept. of Phys., Arizona Univ., Tucson, AZ, USA

Abstract. The authors investigate the processes involved in muon catalysis of hydrogen isotopes with light nuclei Z>1, with the objective of identifying systems in which at least one fusion per muon is possible. They systematically explore all nuclear systems and identify those having the potential to lead to fast fusion rates despite the high Coulomb barrier. They consider in some detail the tunnelling through this barrier as well as the internal conversion of the muon. Furthermore they establish, in qualitative terms, the necessary conditions for muomolecular rates in collisions of muonic atoms of hydrogen isotopes with small concentrations of light elements.

Print publication: Issue 2 (February 1990)

 

[sanman]

p+p is not very efficient. That's the reaction that fuels the sun, and there the p-density is comparable to water at room temperature. The problem with fusion in metallic hydrogen is that as soon as fusion occurs, the metallic hydrogen heats and is no longer metallic hydrogen.

Yes, but if p+p releases enough energy to cause nearby p to collide with B80 shell, then you could get multiple p+B fusions as well, even if the B80 blows apart.

Here is something I found relating to this problem of fusion energy release vs. sustainability of the reaction process:

http://www.informaworld.com/smpp/content~content=a739286799~db=phys~order=page

http://www.informaworld.com/smpp/content~content=a739286799~db=phys~order=page"

Negative muons may be used as a catalyst to fuse hydrogen nuclei into helium. The necessary confinement of nuclei is obtained on a microscopic scale by chemical bonding within 'exotic' muonic molecules such as dtμ, without the extreme physical conditions required for macroscopic plasma confinement in Tokamaks and laser reactors. Fusion energy released by muon catalysis exceeds the rest-mass energy of participating muons, which triggered questions about suitability of this process for energy production. The present article reviews the theoretical studies of the microscopic events constituting the fusion chain. The aim of these studies is to optimize the fusion yield by understanding its dependence on the macroscopic conditions such as temperature, fuel density and/or composition. Apart from the energy production aspects, the field of muon catalysed fusion (μCF) is also a wonderful example of interdisciplinary basic research combining exotic chemistry with atomic, nuclear, and particle physics. While the μCF reactions occur for all hydrogen isotopes, the present review emphasizes the theoretical and experimental results obtained for the case of dtμ.