Wikipedia

Talk:Thermonuclear weapon/Archive 2

< Talk:Thermonuclear weapon
Latest comment: 11 years ago by Sbharris in topic Interstage
Archive 1Archive 2Archive 3Archive 4

Hydrogen Bomb

Latest comment: 15 years ago4 comments3 people in discussion

Why don't someone rename the article? it is the most common name after all, most people have never even heard of the name "Teller-Ulam" before, but surely they'd be familiar with the name Hydrogen Bomb. —Preceding unsigned comment added by Supaman89 (talk • contribs)

This is the most technically correct name for it, and Hydrogen bomb exists as a redirect to this article, so if anyone searches on or tries to go to that article they come here. Georgewilliamherbert (talk) 02:58, 2 July 2009 (UTC)
Yes, but I meant to put it in the article's title, since it's the msot common name. Supaman89 (talk) 23:07, 5 July 2009 (UTC)

Thermonuclear weapon is probably most standard, and that now redirects to Nuclear weapon design, an article with much duplication with this one. --JWB (talk) 04:22, 2 July 2009 (UTC)

It duplicates some of what's here, but in much less detail (as is appropriate for a topic overview article and related specific subtopic article). Georgewilliamherbert (talk) 20:37, 2 July 2009 (UTC)

Acetonitrile

Latest comment: 15 years ago1 comment1 person in discussion

Despite the citation listed, the characterization of acetolnitrile as "highly toxic, highly volatile" is just silly. ACN is an extremely common solvent in chemistry and manufacturing. Its toxicity is mild outside of heavy exposure, and although it is both volatile and flammable, it is no more so than many other commonly used solvents (e.g. methanol). In bio/chemistry labs it is ubiquitous and considered relatively harmless. I expect that, if it does pose a danger in the manufacture of FOGBANK, it's only because of how it's being used (perhaps heated or in large quantities), rather than properties intrinsic to ACN itself. —Preceding unsigned comment added by 209.155.188.226 (talk) 17:13, 1 September 2009 (UTC)


Requested move

Latest comment: 15 years ago23 comments11 people in discussion
The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the move request was not done.  Skomorokh, barbarian  10:33, 20 October 2009 (UTC)

Teller–Ulam design → Hydrogen bomb — The WP:NAME policy clearly states that an article's name be "recognizable", "easy to find" and "only as precise as is necessary." Teller–Ulam design self-evidently fails on all three accounts; the current name fails the WP:NCCN guideline as well: a google search reports 20,700 hits for its current name vs. 461,000 for "hydrogen bomb" and 441,000 for "h-bomb". I am proposing the move on the assumption that a WP:BOLD attempt to move it unilaterally would be contested based on this discussion from July 2009. 72.244.204.89 (talk) 19:56, 11 October 2009 (UTC)

Survey

Feel free to state your position on the renaming proposal by beginning a new line in this section with *'''Support''' or *'''Oppose''', then sign your comment with ~~~~. Since polling is not a substitute for discussion, please explain your reasons, taking into account Wikipedia's naming conventions.
  • Support (sort of). As JWB points out, "hydrogen bomb" is misleading and should be renamed "thermonuclear weapons." Once that move is made, I see no good reason for not incorporating this article into that one. Those interested in the technical details of thermonuclear weapons should be able to find them in an article of that title. NPguy (talk) 03:14, 12 October 2009 (UTC)
Right now thermonuclear weapon redirects to nuclear weapon design which has better detail on the topic than this article. --JWB (talk) 05:14, 12 October 2009 (UTC)
Are you claiming "hydrogen bomb" as used by scientific publications listed below is different than Teller–Ulam design? 66.167.48.24 (talk) 08:33, 13 October 2009 (UTC)
  • Oppose. An article by the name of "hydrogen bomb" would perpetuate the misleading idea that there is such a thing. Redirecting to an article with a more accurate name, i.e., preserving the status quo, seems like a reasonable policy. HowardMorland (talk) 06:15, 13 October 2009 (UTC)
  • Oppose. Specific article for specific topic; as others have noted, "Hydrogen bomb" is somewhere between a superset-article of it and a simple misnomer for that superset. So, per JWB, I think the Hydrogen bomb redirect should be changed to point to nuclear weapon design, which is the article where readers can learn about the whole idea of that topic (and the terminology problem of it) rather than assuming one specific design among apparently several (another idea that is discussed on the more general page). Given that one is a specific example of another topic, I'm not surprised that the more specific/technical one gets fewer g-hits: that would only be relevant if they were truly synonymous. DMacks (talk) 06:22, 13 October 2009 (UTC)
Good point. I agree. HowardMorland (talk) 07:03, 13 October 2009 (UTC)
I'm not sure Teller-Ulam design is the best level of detail for an article title either - a scope like "Early thermonuclear weapons" or "Nuclear weapons in the 1950s" might be better. A question we should ask is, what would be a good choice of first-level subarticle divisions under "Nuclear weapon (design)"? A chronological division by decade or design type seems most likely. --JWB (talk) 23:08, 13 October 2009 (UTC)
A major problem for nomenclature is that boosted fission weapons are also thermonuclear weapons. The distinction between them and two-stage (Teller-Ulam) thermonuclears is mostly academic, important to understanding Oppenheimer's position in 1950 and his security clearance trial in 1954. From almost day one of the thermonuclear age, the major use for fusion-boosted fission bombs was as primaries for two-stage weapons, except for battlefield weapons like the Davy Crockett. The point being, nonetheless, that thermonuclear weapons don't have to be Teller-Ulam devices; they can be single-stage boosters. Single-stage boosted weapons were tested throughout the 1950s, but mostly, of course, for eventual use as primaries in Teller-Ulam devices.
The interest in an article about the Teller-Ulam design is the mystique, the longtime secrecy, the many misconceptions about it, and the fact that the only nations that have it are the five permanent members of the UN Security Council. It is also a nifty technical trick, much more clever than boosting. I think it makes sense to have a separate article about Teller-Ulam, although there is a lot of overlap with Nuclear weapon design.
"Early thermonuclear weapons" or "Nuclear weapons in the 1950s" would not be synonymous with Teller-Ulam, because the Teller-Ulam principle is used in almost all of the weapons deployed today by the big five.
It is a little odd that Thermonuclear weapon redirects to Nuclear weapon design, while Thermonuclear warhead redirects to Nuclear weapon. Oh, well. There is even a title called Thermonuclear fission, whatever that is, which redirects to Nuclear fission. -- HowardMorland (talk) 02:48, 14 October 2009 (UTC)
There is also an article on radiation implosion, which is the generic name for the Teller-Ulam innovation, right? Should it be merged with this article?
Particle accelerator external neutron initiator, gas boosting in primary cavity, and radiation imploded secondary with dry fusion fuel are three innovations that all use fusion, were introduced about the same time in the 50s, and are all integral to mature, compact nuclear weapon design. While each of these could well have a subarticle to discuss their mechanisms in detail if space requires, they have been used together. The particle accelerator does not use thermal equilibrium, though, so I am not sure if it is classified as thermonuclear.
Is it even possible to build a small two-stage weapon without a boosted primary? Slower energy release from an unboosted primary would require a larger radiation case. The early '50s staged weapons before boosting were megaton-yield designs. --JWB (talk) 22:50, 14 October 2009 (UTC)
In addition to Teller-Ulam, radiation implosion also includes inertial confinement fusion experiments in which radiation implosion provides both the compression and the heat to a tiny charge of fusion fuel. In Teller-Ulam, radiation implosion compresses the heat-shielded fusion fuel without heating it (much); the heat comes later from the sparkplug. So they're not the same.
Boosting came slightly before staging; it is desirable but not necessary for staging. The multi-megaton weapons had boosted primaries. HowardMorland (talk) 18:04, 16 October 2009 (UTC)
Wasn't the Swan/Robin primary the first boosted primary, in 1956, after some staged devices had already been tested? --JWB (talk) 20:53, 16 October 2009 (UTC)
My point of reference here is Chuck Hansen's list of nuclear tests in Swords of Armageddon, Vol VIII, Table A-1, pp 154-184. The Greenhouse Item shot on 5/25/51 tested D-T gas boosting. This was two weeks after Greenhouse George had tested a crude form of staging with radiation coupling, but George's secondary did not have a pusher or a sparkplug. Those essential elements of Teller-Ulam were first tested in Ivy Mike on 11/1/52. Hansen doesn't say whether Mike's primary was boosted, but boosting had been tested again, six months before Mike, in Snapper Dog on 5/1/52. Boosting was tested at least three more times in Upshot-Knothole during 1953, to develop the boosted primary called Racer, which was used in Castle Bravo on 3/1/54, the first dry-fueled, potentially deliverable Teller-Ulam device. This is all information that could be worked into the Teller-Ulam article, by the way. HowardMorland (talk) 18:49, 18 October 2009 (UTC)

Discussion

Any additional comments:
  • As of this writing, the survey section contains several comments expressing the opinion that the term "hydrogen bomb" is "highly inaccurate", "perpetuate[s a] misleading idea", and/or a "simple misnomer". Those opinions fail to meet the survey requirement to "take into account Wikipedia's naming conventions" as stated in the introduction to the survey section. In support of the assertion that Teller–Ulam design self-evidently fails the WP:NAME policy that an article's name be "recognizable", "easy to find" and "only as precise as is necessary" and fails the WP:NCCN guideline, I offer a few of the many reputable uses of the term hydrogen bomb:
http://www.nytimes.com/learning/general/onthisday/big/1101.html
http://www.time.com/time/time100/heroes/profile/sakharov01.html
http://www.scientificamerican.com/podcast/episode.cfm?id=58AD0DA4-F12F-B68C-02506A9B55CA95B6&sc=rss (in this one "hydrogen bomb" is used by Dr. Kenneth Ford, former director of the American Institute of Physics)
http://news.bbc.co.uk/2/hi/science/nature/2388027.stm
http://news.bbc.co.uk/2/hi/8225540.stm
http://www.nature.com/nature/journal/v180/n4575/abs/180049a0.html (Nature 180, 49 - 50 (06 July 1957)
http://www.nature.com/nature/journal/v413/n6851/full/413017a0.html (Nature 413, 17-18 (6 September 2001)
http://www.sciencedaily.com/releases/2009/08/090820083442.htm
http://www.lanl.gov/history/postwar/debate.shtml
http://www.au.af.mil/au/cadre/aspj/airchronicles/bookrev/mowbray.html
http://www.defenselink.mil/news/newsarticle.aspx?id=25148
http://newspapers.nla.gov.au/ndp/del/search?searchTerm=Hydrogen+Bomb&textSearchScope=full&facet=decade:195
http://www.globalsecurity.org/wmd/intro/h-bomb.htm
http://www.pbs.org/wgbh/amex/bomb/peopleevents/pandeAMEX56.html

I could go on. Remember WP:NAME is one of the few Wikipedia policies, not just a guideline. So I'd like to encourage editors to accompany their survey positions with aspects of the policy that support the points they make, Thanks. 66.167.48.24 (talk) 08:33, 13 October 2009 (UTC).

  • A good analogy for this would be the 1918 flu pandemic. It is much better known as the Spanish flu. A Google search for Spanish flu turns up ten times more hits than a search for 1918 flu pandemic, but the Wikipedia article is titled 1918 flu pandemic, and Spanish flu is redirected there. The term Spanish flu was used in early press accounts, and the name stuck, because Spain was the first country where reporting was not hampered by military censorship. The outbreak first appeared at Fort Riley, Kansas, and the disease may have originated in Asia. Similarly, hydrogen bomb was coined by journalists who did not know how it works, and use of the term contributed to misunderstanding. HowardMorland (talk) 13:24, 13 October 2009 (UTC)
  • Those are some good links for common use of the term "hydrogen bomb", but they illustrate that the term does not overwhelmingly refer to the Teller–Ulam design of it in particular. Some mean any/all sorts of fusion-involving weapons. The Science Daily one even thinks an H-bomb is mostly fusion-powered, which is explicitly a different sort of thing than T-U warheads, which only use fusion to trigger a more massive fission and state that the real power still comes from the fission reactions. So we have competition between the WP:NAME aims of common usage and precision. common-name and precise. I'll stand by my !vote above in light of this new evidence. DMacks (talk) 18:38, 16 October 2009 (UTC)
The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

Proposed changes

Latest comment: 15 years ago5 comments3 people in discussion

I am working on a new introduction which I think is a more accurate overall description of the topic. My draft is posted at [2]. (My only changes are in the introduction.) It may be long for an introduction, I don't know. I would also suggest merging the three competing explanations into one, which I have not tried to do. I may take a stab at it later. HowardMorland (talk) 17:59, 22 October 2009 (UTC)

Looks great for the most part. I would emphasize a couple of things more:
  1. The "Teller-Ulam design" is not a detailed design in the sense of a specific nuclear weapon design, but a general technique also called "staging" etc.
  1. We don't actually know that the newer non-NPT nuclear powers do not have staged devices. India's Operation Shakti#Shakti I was reported as a staged device test. Israel had a neutron bomb program over 20 years ago and has had plenty of time to develop since then, with computer simulation continuously becoming easier. Pakistan and weapons of mass destruction says Pakistan may have 300-500kt warheads, which is unlikely without staging. --JWB (talk) 19:56, 22 October 2009 (UTC)
There are counterexamples - Orange Herald was single-staged, for example, though a layer cake type design (although there seems to be considerable debate if the fusion was necessary or useful - 117 kg (!) of HEU imploded that energetically will give nearly 720 kilotons without any fusion). And it was reasonably compact - 30 inches / 75 cm. Georgewilliamherbert (talk) 08:09, 23 October 2009 (UTC)
Regarding Pakistan, in http://thebulletin.metapress.com/content/f828323447768858/fulltext.pdf (Nuclear Notebook, the ultimate source), Norris and Kristensen say, "Absent a successful full-scale thermonuclear test, it is premature to suggest that Pakistan is producing two-stage thermonuclear weapons . . ." They estimate the yield of Pakistani weapons at 5 to 10 kilotons. The higher yield estimate comes from a source I consider less reliable. (That Pakistan article is a mess, anyway.)
Regarding India, http://thebulletin.metapress.com/content/v807305523h0v78x/fulltext.pdf questions the validity of the reported yield and the claim to thermonuclear success. HowardMorland (talk) 10:55, 23 October 2009 (UTC)
There is certainly dispute about this, so we should avoid a categorical statement that the new nuclear weapons states do not have staged designs. We could avoid saying anything, or a more accurate statement is that there is much evidence they have worked on staged designs, but not definite evidence of deployed staged weapons. --JWB (talk) 18:29, 23 October 2009 (UTC)

Radiation Pressure vs Plasma Pressure vs Ablation Pressure

Latest comment: 14 years ago7 comments4 people in discussion

I have not yet contributed to this article, preferring to give my attention to Nuclear weapon design. This article is a reasonable expansion of one of the design topics in that article. I do have a small quibble with Teller–Ulam design, which I have not weighed in on because I have a well-known point of view (for plasma pressure) in what seems to be largely a debate between Carey Sublette and myself. (He knows a lot more about physics than I do.)

In Comparing the implosion mechanisms, a set of numbers is presented, apparently taken out of context from Carey Sublette's http://nuclearweaponarchive.org/Nwfaq/Nfaq4-4.html#Nfaq4.4.4 , which seems to settle the debate in favor of ablation pressure. I doubt that simple calculations like this apply very well in this case.

Everyone agrees that in radiation implosion Newton's third law (conservation of linear momentum) must not be violated. The momentum of material being imploded must equal the momentum of material being exploded. The only question is the location of the dividing point between stuff going in and stuff going out. The ablation pressure theory says that enough of the outer surface of the pusher/tamper moves outward (and soon enough) to be the dominant force in driving the implosion. The plasma pressure theory says that the radiation channel filler is designed to absorb the heat and expand so rapidly that very little of the pusher/tamper surface ablates away. It all goes in with the implosion.

Both theories depend on ablation. The debate is about what ablates and what is compressed. I don't think simple pressure calculations are very helpful here. For one thing, timing is critical. If designers want to compress the pusher/tamper to maximize its fission yield in the final event of the detonation, especially when the pusher/tamper is made of fissile U-235, they would want to delay any tendency for the pusher/tamper to ablate away during its implosion. There are various ways they could do this.

It is well known that efforts to make computer simulations of what is happening and when, based on data from nuclear tests, taxed the capacity of computers of the day, and in fact spurred their development. I attempted to finesse this issue in footnote #39 of Nuclear weapon design: "The public literature mentions three different force mechanism for this implosion: radiation pressure, plasma pressure, and explosive ablation of the outer surface of the secondary pusher. All three forces are present; and the relative contribution of each is one of the things the computer simulations try to explain."

I think it would be safer to conclude the debate in this article with a statement like that, rather than to announce a winner among the three theories.

HowardMorland (talk) 08:44, 13 October 2009 (UTC)

I agree this is a complex issue. The secondary might also have an intermediate-mass outer pusher layer. Depending on whether this is considered as part of the secondary or part of the radiation channel, you might call its pressure ablation pressure or plasma pressure. It seems to me the 2-3 force mechanisms are not really distinct. What is most significant in my view is thermal equilibrium inside the radiation case; once this is realized, force exerted per area of both radiation case inner surface and secondary outer surface will be relatively constant, regardless of the transfer mechanism. --JWB (talk) 18:47, 14 October 2009 (UTC)
That's only true very briefly, early in the implosion process. The integrity of the radiation case is disrupted by its own ablation process - inwards and outwards. As it's thinner than the ablator/tamper for the secondary, that happens while not much physical ablation has happened in the bulk volume of the secondary yet. Once the radiation case has been disrupted (density due to ablation drops to the point that it's no longer optically thick) the energy formerly contained now becomes very free.
What's important is that the radiation front into the tamper moves fast enough that a lot of energy is deposited in depth before the surface ablation and the radiation case ablation disrupt the energy transfer. Georgewilliamherbert (talk) 03:31, 17 October 2009 (UTC)
Thermal equilibrium is a description of your second paragraph, right? Also, the radiation case is thinned not only by ablation (expansion perpendicular to its surface back toward the radiation cavity) but also by expansion outward which increases surface area and decreases mass per unit area.
As a simple case let's assume the radiation case and tamper are the same material, the radiation cavity filler is homogeneous, and temperature is equalized within the radiation cavity. Each unit area of either the inner or outer surface should absorb the same amount of energy. Initially this is thermal energy and some of it is later converted into (macroscopic) kinetic energy, but it is the same amount of energy. If the tamper surface is 10% of the total area, it should get 10% of the heat that is absorbed, not saying how much of the total heat is absorbed and how much is still bouncing around as photons. Again for simplicity, assume at some point the radiation case is disrupted and energy absorption after that is negligible. Then the energy absorbed by the tamper is just the product of the total proportion of radiation that has been absorbed, times the tamper's fraction of total cavity surface area. --JWB (talk) 05:04, 17 October 2009 (UTC)
Ablation happens in both directions, on materials thin enough that they get heated all the way through, and the radiation case is clearly not so thick on modern weapons that the outside says cool "long" into the system's evolution... It expands in both directions, as it's hotter on the inside ablating more in that direction, but also to the exterior to a noticable extent.
The fallacy is in assuming that the energy is effectively absorbed into the tamper/pusher. There's a wave front of energy moving into it - in physical terms, think of an energy shockwave. With explosives, for thin layers of explosives, you get a shockwave into material followed by a rarefaction wave as the back side pressure drops off. You get the same effect in the tamper/pusher - it's still re-radiating like mad as the radiation case falls away, as (assuming like or similar materials) the penetration depth into both will be similar by the time the radiation case goes poof. Once the RC goes poof, then not just its energy, but the thermal reradiation from the tamper within roughly an optical thickness of the surface immediately becomes relevant, and that reradiation is just lost to empty space as there's nothing to hold it in.
At the time of case disruption, the proportion based on relative surface areas is roughly correct, if the speed of radiation diffusion is fast compared to the ablation of the radiation case, which is a reasonable working assumption. But that energy distribution doesn't get fixed at that point and stay that way. There's effectively an energy density rarefaction that forms once the radiation case expands and ionizes, and that reduces the energy in the tamper/pusher.
The term "absorbed" is sort of a misnomer. You're not absorbing it - it doesn't stay where it lands, it is reradiated in a random direction. Absorbtion would imply it stays somewhere - when, in fact, at the moment of equilibrium in the radiation case, everything is hot enough to reradiate away at a rate equal to the rate of infalling photons, sort of by definition. The reradiation is sort of unavoidable, there's no one-way gate for photons entering the tamper/pusher. As energy is diffused further into the material, you get a longer time for it to be re-radiated back out, and fractions travel inwards instead of outwards, but the tamper/pusher optical surface (wherever that is, with ablation and ionization bleaching progressing) is always reradiating...
Georgewilliamherbert (talk) 06:57, 21 October 2009 (UTC)
I don't think we are disagreeing on anything. One additional thought, though, is that as the cavity temperature drops as the radiation case becomes permeable, medium-Z material in the radiation case filler may become opaque again and provide some additional reflection of lower-temperature heat back to the secondary. --JWB (talk) 20:49, 21 October 2009 (UTC)

Clarification of the role of plastic foam in delaying outer case ablation: Richard Rhodes' book Dark Sun stated that a one inch thick layer of plastic foam was fixed to the lead liner of the inside of the Ivy Mike steel casing using copper nails. Rhodes quotes several designers of that bomb explaining that the plastic foam layer inside the outer case is only there to delay ablation and thus recoil of the outer case: if it wasn't there, metal would ablate from the inside of the outer case with a large impulse, causing the casing to rapidly recoil outwards. The whole point of the casing is to contain the explosion for as long as possible, allowing as much X-ray ablation of the metallic surface of the secondary stage as possible, so it compresses the secondary efficiently, maximizing the fusion yield. Plastic foam has a low density so causes a smaller impulse when it ablates than metal does. 82.21.58.162 (talk) 14:51, 26 February 2010 (UTC)


X-rays (again)

Latest comment: 14 years ago4 comments3 people in discussion

It was already mentioned that there is no mirror for X-rays comming at the angle of order of 45degrees. I would remove figire   from this and from other articles. This figure is confusing. dima (talk) 15:36, 17 April 2008 (UTC)

X-rays aren't bouncing. Hard gammas are emitted by the very high temperature fissioning pit (by fissions, and by thermal radiation). They go in straight lines until they encounter enough mass to be absorbed (generally, the inside of the radiation case). They heat up what they are absorbed in. Shortly, the inside of the radiation case around the primary is hot enough that it's emitting X-rays, which travel in straight lines until they hit something dense enough to absorb them, which they heat up, etc etc. This happens for a number of cycles. See "photon gas" in the Nuclear Weapons FAQ, and the meaning of the term Hohlraum or "radiation case". Georgewilliamherbert (talk) 02:23, 19 April 2008 (UTC)

The capture reads:"Fission primary emits X-rays which reflects along the inside of the casing"... It is confusing. Could you reword this, according to your explanation above? dima (talk) 13:43, 19 April 2008 (UTC)

My understanding is that gammas emitted by the primary travel (in straight lines, of course) and completely ionize the 'foam' (or plastic); the foam consists primarily of carbon and hydrogen. Nanoseconds later, the nuclei of the atoms (previously making up the 'foam') re-capture the electrons, and in doing so they emit a spectrum of X-rays corresponding to (mostly) the ionization energy of the carbon atoms. These X-rays are emitted spherically-symmetrically, but enough of them fly in the direction of the secondary. Perhaps the secondary is surrounded by a carbon-containing layer to optimize the absorption of these X-rays. 174.25.175.217 (talk) 05:36, 24 May 2010 (UTC)

Non insensitive high explosives

Latest comment: 14 years ago3 comments2 people in discussion

It should be noted that non insensitive high explosives are a feature of the W87 as well as the W88, because given that the W87 is adjacent to the third stage of the missile it makes little difference which kind was used. In general SSBN physics packages aren't held quite as strictly to standards as other physics packages due their operational environment. (I.E. they aren't likely to dropped over friendly territory accidentally, etc... etc...) 24.16.181.1 (talk) 02:04, 10 August 2010 (UTC)

It makes a huge difference, even sitting next to a solid rocket motor, as the difference between "caught fire" and "caught fire and detonated" is a huge, huge safety impact.
Every reference on the W87 lists IHE. Including the handling procedures docs for what warheads can't be shipped by air other than in an emergency, because they have non-IHE primaries, which say the W87 is fine for air shipment...
Georgewilliamherbert (talk) 07:37, 10 August 2010 (UTC)

The use of non insensitive explosives in the W87 and the safety regulations is discussed in Spinardi. I don't recall that we were told one way or another, which isn't surprising as there's more material on some matters available in the open literature than the classified. (The converse is also true for other matters.) 24.16.181.1 (talk) 11:23, 16 August 2010 (UTC)

Focusing

Latest comment: 14 years ago1 comment1 person in discussion

Why isn't there a discussing of focusing in this article? I read a blurb in the Swords of Armegeddon book (page I-137 in VOL I) that said focusing is important in a multistage weapon to get the soft x-rays from the primary to the secondary, or the secondary to the tertiary or the tertiary to the quaternary. This is achieved by a/an elliptical chamber(s). How this would look for an n-stage nuke is what I'd like to know. —Preceding unsigned comment added by 71.155.241.151 (talk) 04:33, 6 September 2010 (UTC)

Wow

Latest comment: 14 years ago3 comments3 people in discussion

I can't believe this article is new. It's gorgeous. Scary topic, of course, but v. nicely done. jengod 02:58, July 25, 2005 (UTC)

Thanks, it's just something I've studied for awhile, so I had all of the references handy. --Fastfission 10:51, 25 July 2005 (UTC)


I skimmed through the article a bit and didnt really look for it but i did hear that hydrogen bombs explode the air molecules when they go off Atvrider365 (talk) 20:40, 28 October 2008 (UTC)

Nuclear weapons need periodic replacement of "limited life" components, namely the neutron generator and DT gas bottle, but it is done much less frequently than every three years. 71.198.141.131 (talk) 01:01, 18 November 2010 (UTC)

X-rays

Latest comment: 14 years ago5 comments3 people in discussion

The article describes "X-rays ... which reflect along the inside of the casing" and the diagram gives the impression that X-rays ricochet around the inside of the casing. It is pretty hard to make X-rays reflect: they either pass through or are absorbed by the reflecting medium. Astronomical X-ray telescopes (Chandra, XMM, ASCA) are forced to resort to grazing incidence and nested nearly-cylindrial mirrors.

There is a much better description in radiation implosion:

The term reflector is misleading, since it gives the reader an idea that the device works like a mirror. Some of the X-rays are diffused or scattered, but the majority of the energy transport happens by a two-step process: the X-ray reflector is heated to a high temperature by the flux from the primary, and then it emits X-rays which travel to the secondary. Various classified methods are used to improve the performance of the reflection process.

This seems to imply that the casing is irradiated such that it fluoresces in the X-ray. -- ALoan (Talk) 08:31, 25 July 2005 (UTC)

Hmm, that's interesting. I'd appreciate it if anyone with technical insights could help smooth out that section of the article — I am not a physicist, and am likely to make mistakes (I thought they were "reflected" like a mirror, I must admit, but I have no idea about such things except what I have read, none of which is what I'd call "technical literature"). My only fear in such things, of course, is that I don't want the article to have too much confidence in things which are not securely known (i.e., the secret things), but with a little care that can be avoided. --Fastfission 10:55, 25 July 2005 (UTC)
Also, about the diagram: I've never seen it drawn any other way than "reflecting" like that. I can't think of a better way of drawing it though. --Fastfission 17:15, 25 July 2005 (UTC)
Just as a note: I updated the text to reflect this better. --Fastfission 17:20, 6 August 2005 (UTC)

Fastfission: after interviews with the Ivy-Mike bomb designers, Richard Rhodes corrected the situation on page 486 of "Dark Sun" (Simon and Schuster, N. Y., 1996):

The flux of soft X-rays from the primary would flow down the inside walls of the casing several microseconds ahead of the material shock wave from the primary. ... the steel [OUTER] casing would need to be lined with some material that would absorb the [soft X-ray] radiation and ionize to a hot plasma which could [re-]radiate X-rays [towards the secondary stage, like a mirror] to implode the secondary.

So what the plastic foam does is act as a mirroring surface to reflect back X-rays going toward the outer casing, instead of losing that energy by having it ablate the outer casing. You must reflect those outgoing X-rays back on the fusion fuel capsule in the middle of the radiation channel, so they ablate that, instead of using up the X-ray energy to ablate the inside of the outer bomb casing! Rhodes on page 501 of "Dark Sun", quotes Mike designer Harold Agnew:

I remember seeing the guys hammer the big, thick polyethene plastic pieces inside the casing ... They hammered the plastic into the lead with copper nails.

The plastic foam is just one inch thick (it doesn't fill the radiation channel, and it it did the bomb would fail because of the X-rays would not be focussed on the secondary stage by reflection), so it is purely a Teller "radiation mirror" for the X-rays; reflecting as much X-ray energy back on to the fuel capsule as possible. The plastic foam doesn't fill the entire casing, it's just a relatively thin (1" thick) layer fixed to inside of the outer case. Rhodes, however, was still confused and reverts to Hansen's error on page 492, stating that the plastic foam "would expand rapidly and deliver the necessary shock [to the fusion fuel capsule]". This is untrue; the physical expansion of plastic foam and its "shocking up" into a shock wave takes far longer and exerts far less pressure than the delivery of X-ray energy.

Plastic foam is vital to make the inside of the outer casing into a "radiation mirror" for X-rays. Instead of ablating a metal surface and wasting the energy by transforming it into mechanical kinetic energy of ablating metal vapor and recoil shock in the outer case, because of its low density (compared to a metal) the plastic foam simply heats up and re-radiates the energy it has absorbed as X-rays. This turns it into an excellent mirror for X-rays, since the incident X-ray energy is mostly re-radiated instead of being turned into mechanical shock wave.

To understand this important mechanism in slightly different context, see Glasstone and Dolan, "The Effects of Nuclear Weapons" 3rd ed., 1977:

Two factors affect the thermal energy radiated ... First ... a shock wave does not form so readily in the less dense air [or any less dense medium!] [Paragraph 1.36, p. 10.[3].]
At high altitudes shock waves form much less readily in the thinner air and consequently the fireball is able to radiate thermal energy that would, at lower altitudes, have been transformed to hydrodynamic energy of the blast wave. [Paragraph 7.90, p. 315.[4].]

Plastic foam is able to mirror X-rays because it is able re-radiate X-ray energy efficiently: its low density slows down the rate of shock wave formation, eliminating that mechanism for energy loss, so plastic foam merely heats up and re-radiates the energy as X-rays.

(The plastic foam "mirroring" of X-ray radiation is vital to the Teller-Ulam design as evidenced by the declassified title of their 9 March 1951 joint Los Alamos LAMS-1225 paper: "On Heterocatalytic Detonations. I. Hydrodynamic Lenses and Radiation Mirrors" [5]. The "radiation mirrors" concept is the Teller contribution: this is the key to the whole breakthrough; Ulam's hydrodynamic lenses never worked for the shock wave from the fission primary which is too dense and slow to focus. It is absurd that the one key breakthrough, Teller's radiation mirroring, is completely misunderstood by Rhodes and others, because they don't understand that the difference in density between plastic foam and metal reduces shock wave formation and thus makes plastic into a relatively good radiation mirror.) 82.21.58.162 (talk) 11:20, 22 November 2010 (UTC)

Latest comment: 13 years ago1 comment1 person in discussion

The image File:China H-bomb 1967.jpg is used in this article under a claim of fair use, but it does not have an adequate explanation for why it meets the requirements for such images when used here. In particular, for each page the image is used on, it must have an explanation linking to that page which explains why it needs to be used on that page. Please check

  • That there is a non-free use rationale on the image's description page for the use in this article.
  • That this article is linked to from the image description page.

This is an automated notice by FairuseBot. For assistance on the image use policy, see Wikipedia:Media copyright questions. --21:36, 11 February 2011 (UTC)

malicious changes

Latest comment: 13 years ago2 comments2 people in discussion

Hi, I don't know how this works exactly. I would like to draw the attention of the authors to changes in the text which have clearly been made maliciously, e.g. dildo.

Fonserl (talk) 17:53, 5 April 2011 (UTC)

Don't worry; such things don't last long. — UncleBubba ( T @ C ) 18:42, 5 April 2011 (UTC)

File:OperationGrappleXmasIslandHbomb.jpg Nominated for Deletion

Latest comment: 13 years ago1 comment1 person in discussion
  An image used in this article, File:OperationGrappleXmasIslandHbomb.jpg, has been nominated for deletion at Wikimedia Commons in the following category: Deletion requests October 2011
What should I do?

Don't panic; a discussion will now take place over on Commons about whether to remove the file. This gives you an opportunity to contest the deletion, although please review Commons guidelines before doing so.

  • If the image is non-free then you may need to upload it to Wikipedia (Commons does not allow fair use)
  • If the image isn't freely licensed and there is no fair use rationale then it cannot be uploaded or used.

This notification is provided by a Bot --CommonsNotificationBot (talk) 19:24, 25 October 2011 (UTC)

United States v. The Progressive

Latest comment: 12 years ago1 comment1 person in discussion

This is a fascinating legal case, anyone want to collaborate on improving the page with me? Please leave a note on my user talk page, — Cirt (talk) 19:01, 16 February 2012 (UTC)

Move to hydrogen bomb

Latest comment: 12 years ago7 comments6 people in discussion
The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page or in a move review. No further edits should be made to this section.

The result of the move request was: procedural close, as nominator withdrew the request and started a new discussion just bellow this section. Armbrust, B.Ed. WrestleMania XXVIII The Undertaker 20–0 06:29, 6 July 2012 (UTC)

Teller–Ulam design → hydrogen bomb – "hydrogen bomb" redirects here. "hydrogen bomb" is no doubt more common term. Also, I feel there is more than just the design of a hydrogen bomb that Wikipedia should cover: political/social aspects, say. The new name broadens the scope of the article. -- Taku (talk) 10:52, 29 June 2012 (UTC)

By the way, this same move was proposed in October 2009 and the discussion is preserved above, under Requested move. The proposal was defeated, although that shouldn't stop us from reconsidering. Everyone should read the preserved discussion, which covers many important points. --ChetvornoTALK 04:56, 30 June 2012 (UTC)

The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.

Move to Thermonuclear weapon

Latest comment: 12 years ago8 comments6 people in discussion
The following discussion is an archived discussion of the proposal. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the proposal was Move Mdann52 (talk) 18:15, 8 July 2012 (UTC)(non-admin)

Teller–Ulam design → Thermonuclear weapon – The same reason as before: WP:COMMONNAME. It's simply too bizarre not to have an article on this topic (or equivalently on hydrogen bomb). Maybe hijacking this page is a wrong approach? Maybe. But this allows us to avoid having duplicated materials. We need one main article; create a sub article if needed. From what I hear "Thermonuclear weapon" is a winner :) Also, there was a similar discussion in 2009. But the consensus can change and also this is a slightly different proposal. -- Taku (talk)

  • Still oppose – the fix for not having an article on thermonuclear weapons is not to move the article on the technical design details of a particular form of thermonuclear weapon. Dicklyon (talk) 23:45, 30 June 2012 (UTC)
    • Actually, that was my initial proposal. There are objection to creating an article on the topic since that would result in duplicated content.; whence, this request. -- Taku (talk) 23:47, 30 June 2012 (UTC)
  • Support unless someone convinces me there are significant "thermonuclear" weapons which do not use the Teller-Ulam design. The lead sentence of the article says T-U is the design used in most of the world's nuclear weapons. Dicklyon, what types of "thermonuclear weapon" do not use T-U design? Neutron bombs use it. The only type I have heard of is boosted fission weapons, which are not used independently anymore but only as first stages for T-U weapons. Anyway, I wouldn't classify a "boosted" fission bomb as "thermonuclear" but as fission; it gets most of its yield from fission. Give me some examples. --ChetvornoTALK 00:23, 1 July 2012 (UTC)
Nobody is claiming there are other important designs. But this is an article on the design, i.e. how they work, not on the weapons. Maybe a split is in order... Dicklyon (talk) 01:30, 1 July 2012 (UTC)
As noted, such a split exists already. The stuff on thermonuclear weapons that is NOT about how they work, resides in the article on nuclear weapons.SBHarris 01:49, 1 July 2012 (UTC)
  • Support rename Even if there are a small number of initial thermonukes that worked (poorly) by the initial layer-cake or alarm-clock configuration, that can be discussed in the historical section and noted as "early H-bombs/thermonukes that were NOT Teller-Ulam". This is about one paragraph, and is not enough to keep the article from being renamed to "thermonuclear weapon" (with "H-bomb" and "hydrogen bomb" redirected to it, as now). And yes, I think that the fix for not having an article on thermonukes is INDEED to rename this perfectly good article about how all modern thermonukes work (indeed, all since 1955). It's appropriate. One might argue that it needs some more information on thermonukes in the world that doesn't involve how they work. But all that arms-control and other delivery stuff is all in nuclear weapon, now. The *thermonuclear* weapon-specific stuff in that article is in need of a subarticle on thermonuclear weapons, but the subarticle specific material naturally mostly involves technical details and history of this particularly type of weapon (thermonuke rather than just fission), and so nearly all of that is related to Teller and Ulam's design. Incidently, by all accounts, Sakharov had the same ideas independently (a bit later), giving thermonukes to the Soviets almost as soon as the U.S. had them, and so actually a number of people thought of this design. That's another reason not to discuss the design under the names of these two people as a main heading. They thought of it first, but other people thought of it also. SBHarris 00:35, 1 July 2012 (UTC)
support - mostly. I think there is room for a general article on thermonuclear weapons, separate from both nuclear weapons and this one. The issues of weapons design issues could be addressed in greater detail here, and issues of history and current status in the separate article. NPguy (talk) 01:00, 2 July 2012 (UTC)
The above discussion is preserved as an archive of the proposal. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

Lead needs updating

Latest comment: 12 years ago2 comments2 people in discussion

Now that the article is called "Thermonuclear weapon", the first sentence in the lead should discuss thermonuclear weapons instead of the Teller-Ulam design. RockMagnetist (talk) 00:14, 10 October 2012 (UTC)

Thanks for reminding us. Indeed a lot of the lead had to be rewritten, and I have taken a whack at it. SBHarris 04:28, 10 October 2012 (UTC)

Interstage

Latest comment: 11 years ago4 comments3 people in discussion

Read this interesting post today: FOGBANK (see also Carey Sublette's comments). There's nothing really on interstage in the article. Maybe someone with knowledge of this could add something? Obviously the blog post is speculative in many ways, but Sublette's comments seem to make sense. It would integrate the "exploding foam" and the "ablation" models quite well if true. --98.217.8.46 (talk) 16:42, 17 March 2008 (UTC)

Additionally, General Atomics sells Inertial Confinement Fusion capsules filled with Aerogel (it's in their catalog). This might be further evidence. — Preceding unsigned comment added by DoYouKnow (talk • contribs) 22:44, 8 June 2013 (UTC)

"FOAMS - "GA/Schafer produces a variety of foams that are used for targets to prevent diagnostic hole closure or to support diagnostics or capsules the foams currently available are listed below... " They list "Resorcinol-Formaldehyde Aerogel", and "Silica Aerogel". the Resourcinol one with density ranges of 20-850mg/cm^3, and Silica Aerogel with density ranges of 10-700 mg/cm^3. If the aerogel is used, it may at least partly be used to the wide density tuning and its usage to support the fusion capsules within the hohlraum. — Preceding unsigned comment added by DoYouKnow (talk • contribs) 22:53, 8 June 2013 (UTC)
You're probably onto something, there, DoYouKnow. And since I have no government contact or clearance, I am free to speculate and take off on your comment. If you read the FOGBANK blog post above FOGBANK and focus on acetonitrile, it looks like acetonitrile is necessary as a solvent to make FOGBANK, which is probably low density low-Z X-ray absorbing polymer in the hohlraum. Not silica gel. And guess what? If you look up "resorcinol-formaldehyde aerogels," (google it) you find out that they are copolymers which are made in acetonitrile as the favored solvent. [6]. So that fits. It fits very well. SBHarris 00:48, 9 June 2013 (UTC)
Retrieved from "https://en.wikipedia.org/w/index.php?title=Talk:Thermonuclear_weapon/Archive_2&oldid=1089898147"