Wikipedia:Peer review/Teller-Ulam design/archive1

Teller-Ulam design

I wrote this up over the course of a few days last week, it was a DYK feature and got some other attention that way, which seems to have culled out most of the typos, etc. What do you think? Is there anything which could be tightened up, anything which is unclear, anything missing that you can think of? The goal was to write an article which 1. explained the supposed principle, 2. explained its history in the US and elsewhere, 3. explained how we know what we know about it. Thanks. --Fastfission 11:40, 26 July 2005 (UTC)

I've read and reread this article several times now, and - apart from the ten or so red links - I can't see nothign that can be fixed up before you go to FAC. I mean, the only thing missing is a numbered list of parts and instructions on how to build one in the backyard ;). Impressive piece of work. WegianWarrior 09:06, 27 July 2005 (UTC)

Thank you. All of the red links are things which should, but don't yet, have their own articles. I'll try and create some stubs for them, though, for now. --Fastfission 11:18, 27 July 2005 (UTC)

Good article. A couple of points/questions:

• The article states "Because of the "staged" design, it is thought that a tertiary section, again of fusion fuel, could be added as well, based on the same principle of the secondary." Are there any known examples of a tertiary design having been tested? If not it might be worth mentioning that in the article.
• Are all Hydrogen bombs thought to be based on the Teller-Ullam design?
• I can add some more about the British design. For instance after the successful Grapple tests the US agreed to share it's nuclear secrets with Britain. As a consequence the British based their further H-bombs on an American design (this was kept secret at the time). I should add this information to the Operation Grapple page too. (This information came from the programme used as the reference on that page). CheekyMonkey 22:39, 27 July 2005 (UTC)

Good questions! My response as best I can:

• At least one U.S. design is thought to have had a tertiary stage, and the Tsar Bomba is thought to have a number of secondaries and/or tertiaries. I've added this info to the article. The advantage to noting about tertiaries is that you can use this design to indefinitely scale up the yield of a bomb (hypothetically even to the level of a Doomsday machine, though I thought mentioning that might be a little hyperbolic).
• Such is what is thought, but of course it is hard to know these things for sure. I've added a small line on this. I'm very cautious, personally, on concluding about how much is known, since how much is unknown is itself an unknown quantity (until the idea of the implosion bomb was revealed in 1951, everyone in the public domain thought they knew what the single model of atomic bomb design was, as a small example).
• That would be great. My only real knowledge of the UK program, besides that they were allowed to use some fallout design and had difficulties producing it at first, was that their knowledge of the Teller-Ulam design served as the "secret password" to their being able to share nuclear info with the U.S., which is somewhat interesting in terms of the role secrecy plays.

--Fastfission 15:37, 28 July 2005 (UTC)

I concur with your thoughts on the first two points. Regarding the UK I have added a link to the 1958 US-UK Mutual Defence Agreement and will add some more information over the next couple of days. I must note that the Channel 4 program about this subject (Summary here) never actually stated that the British had come up with a Teller-Ullam design. However, the successful British H-Bomb - Round C was described as "a two-stage thermonuclear bomb with a much more powerful atomic trigger [than the previous British attempts]". Radiation levels being calculated from the trigger were also mentioned. That coupled with the fact that the Americans were impressed enough to share their own designs I think makes it as sure as you can get with this topic that the British were in fact using a Teller-Ullam design. CheekyMonkey 17:24, 30 July 2005 (UTC)

Aaaaarrrrggghhhhhh, not the foam plasma pressure fallacy again! Doesn't anyone read the FAQ anymore? Nuclear Weapon FAQ Sect 4.4.4.2.2, Radiation Channel. The implosion pressure does not come from the filler foam. It's possible to build and fire a Teller-Ulam device with a completely empty radiation channel in the radiation case. The foam is there to retard initial liner and pusher ablation long enough for the energy distribution to even out smoothly. The pressures generated are trivial compared to those required to implode the secondary. What generates the implosion pressure is the ablation (effectively as if it were an in-turned rocket motor) of the fusion pusher layer of the tamper/pusher assembly. A large portion of the tamper/pusher ablates away in this process, leaving a thinner tamper layer up against the now-compressed fuel layer.

I know Moorland's article said that the foam plasma pressure was significant, but Morland wasn't a bomb physicist, and we know a lot more now than we did then. These inaccurate descriptions have got to stop, they're grossly misleading everyone.

I can rewrite the article's implosion description sometime this week, but for now, it flunks peer review on that basis. Sorry. It's not your fault for believing the Morland article, but Morland got that detail (and several others) wrong... Gotta get it right here. Georgewilliamherbert 09:08, 8 August 2005 (UTC)

No, reread the article. It states very clearly that the foam was one idea of it, and that others have different ideas. Sublette and Morland and Rhodes and all of the other people here argue till the sun comes out, and neither of them really have any real idea. So don't change it to one or the other -- the goal is to present all of the ideas taken seriously by these fellows (and the wider world) because none of us have security clearances and there's no way to know which is completely correct. That's half the point of the article if you read it over again -- to tell what is thought to be known, and to emphasize how that knowledge was constructed. Sublette is no more a bomb designer than Morland or Hansen was (Morland and Sublette still disagree about this, by the way, and both claim different types of evidence either way. But I can't include that information because it is original research, I'm afraid). In fact, none of the people who speculate about these things are bomb designers -- we don't "know" more than we did then in any concrete sense. --Fastfission 12:45, 8 August 2005 (UTC)

Which is to say more specifically, I'm happy with adding more on the non-foam explanation than is currently there, and a note that there is some disagreement among people who dream about such things. But I'm not interested in privileging one explanation over another -- I don't see any good reason to believe that any of them is firmly rooted is accurate knowledge. Nobody speculating about such things has any practical idea how X-rays, fission weapons, and fusion fuel operate in such conditions, so I think it's a little early to say one is "right" and another is a "fallacy". --Fastfission 12:57, 8 August 2005 (UTC)

I'm sorry, but if you don't have enough physics background to look at the proposed mechanisms involved (foam plasma pressure, versus the ablation effect Sublette describes) and see whether they actually work, then you shouldn't be stating that there's some debate about which idea is accurate or not.

There are a number of people with that background, including myself, who have looked at the problem and concluded that Carey's analysis and mechanisms are accurate. This includes actual real world peer review by professional physicists involved in collapsed matter physics, inertial confinement fusion, radiation transport, and related fields.

It also includes comments we've received from people "inside" weapons design programs in the US and elsewhere, and non-weapons-designers in government nuclear policy programs. We have been told that the Nuclear Weapon FAQ information is nearly completely accurate and has accurate physics.

There's also stuff which we know is accurate from conversations with engineers and policy people in various countries which is not in the Nuclear Weapons FAQ. Including some physics and a lot of design details of nonspherical primaries, which Carey and I both independently derived in largely accurate forms before we got inside comments which confirmed it. Carey was asked to keep the concept out of the FAQ in the late 90s. The concept has since separately leaked, following the China/W-88/Wen Ho Lee debacle, but none of the published reports have anything like the level of detail we know from analysis and side channel confirmation.

You asserted earlier that “none of us have security clearances and there's no way to know which is completely correct”. The first is partially correct; nobody who has contributed to the Nuclear Weapons FAQ directly has the Q bomb design clearance in the US or foreign equivalent. Lots of hints and side channel confirmations have been indirect information from people with security clearances. The second is not correct; the nuclear weapons establishments aren't completely opaque, and they have told us stuff, and what they've told us is that we have the analysis right.

A combination of open, specialist professional physicist review of the basic physics and the admittedly limited information which has come out of the black side of things is a significant way to know which is completely correct.

The Nth_Country_Experiment had significantly less resources than Chuck Hansen was able to put together; which was less than Carey Sublette was able to pull together.

You say that “none of the people who speculate about these things are bomb designers”. Well, I disagree. We've been told by professional bomb designers that we know enough to be bomb designers. We haven't done complete detailed designs, as the US classification laws for born secret bomb designs appear to make doing so illegal. But you can safely assume we've done a lot of component or partial system designs over the years. Georgewilliamherbert 22:06, 8 August 2005 (UTC)

--As also noted on the Talk: page for the article, I intend to fix the foam plasma section Wednesday night Aug 10. Georgewilliamherbert 03:02, 10 August 2005 (UTC)

Nth Country Experiment was about a fission weapon, not a fusion one. And we're also not completely sure what they ended up concluding since the only thing released about it is was a summary which was heavily redacted. Which you'd know if you'd read the actual report!

...Which I did when it was first published in declassified but redacted form. What on earth made you think I hadn't read it?

Here's one question for you: Who can you cite about the "fallacy"? Carey Sublette's page, sure. But who else? What published sources, for one thing?

...The whole body of inertial confinement fusion literature, for one? They work the same way, just with a lot higher energy density. But everyone in IC fusion knows that the technology is similar and in fact, some of the IC fusion details from government labs are classified, even though they're not military programs.

Even among the better online sources there is ambiguity. From the generally good page at GlobalSecurity.org: "Whether the hot plastic does the pushing or transmits its heat to a designated ablator which does the pushing a matter of continuing public speculation."

So your argument basically comes down to, "Carey Sublette and I agree on this." Which sounds a lot like Original research, since aside from one source, you are citing yourself and your own "calculations".

...And condensed matter physics professors, Intertial Confinement Fusion researchers, and a cast of thousands more...

The goal of our article should be to report on the general status of the knowledge, which in the larger literature is uncertain. So both explanations should be discussed, and we shouldn't try to push one over the other in any major way, in my opinion, because there is no authority which has validated either one.

Now, look, this is just not right. You're taking a narrow view and assuming that "the popular literature" is "the literature". That's just wrong. There are direct linkages in IC fusion, and published papers and books and such in open literature on behaviour of matter once it reaches the fermi gas state, how energy is absorbed by high and low Z materials, etc. Both those subject field experts and the bomb people have admitted that those fields are directly applicable to bomb design.

You're essentially saying here that we can't use professional, academic, peer reviewed information, because the popularized public literature says something different. And that's just wacky.

None of the physics in the NW FAQ is original research. It all came out of other unclassified sources. Putting it all together, tying the bits from IC Fusion and condensed matter physics and radiation transport all together, was original by Carey, but the sources and references and methods are all there. People in all those fields have peer reviewed the NW FAQ and found it accurate. Simplistic, in some areas, but there are pointers to the actual research in those fields for you to go follow up if you want or need the full details.

For any reasonable definition of "published" other than "on paper", the NW FAQ has been published, for a decade now. For any reasonable definition of "peer reviewed", it has been peer reviewed, and passed that review. And the references in the related fields are all out there for you to follow up with, if you still don't believe it.

You acknowledge that you aren't an expert. In asking for peer review, you asked for expert input. It appears that you weren't actually expecting to get it and aren't exactly sure what to make of it now that you have it. You seem to have bought into the "it's such a hard and such secret topic" fallacy, which was disproved by the first nuclear bomb designed by someone with no classified knowledge and outside the weapons community. There have now been several well publicized designs, including by high school and college students. It's just not that hard. Carey tied all the declassified bits together along with the related basic physics and closely related applied physics field specialty research, in a rigorous manner. It's just not that hard anymore.

Georgewilliamherbert 04:53, 10 August 2005 (UTC)

And to be honest -- I trust things which are based in declassified docs a lot more than I do any non-weapon designer's back-of-the-envelope calculations. Sure, you know your physics, but do you actually know how the conditions of a thermonuclear explosion would play out in reality? How would you know what you don't know, what effects you aren't taking into account if you aren't doing work in that field and haven't been privy to their experiments?

Ah, but of course. Carey was asked to keep it out of the FAQ -- everyone who has worked on "bomb speculation" has their story about the men in the gray flannel suits who show up to tell them to keep quiet. Assuming this is true, it is clear (at least from the Morland case) that just having such men around does not guarantee one has gotten everything correct, just that they consider it provocative!

Wikipedia is an encyclopedia, not a place to pretend we know secrets. The goal of this article for me was to portray what is thought to be known, the supposed history of it, and how all of this came to thought to be known. Every aspect of it is dashed with bits of uncertainty and is an effort for the reader to see how such public knowledge of "secret" things is constructed, from bits and pieces and leaks and so forth. To replace it with an article which claims one is true -- because you yourself (and one other person) came to a single conclusion on it -- would be misleading, inaccurate, and an intellectual shame. Feel free to make your edits, but I will be vigilant about enforcing NPOV. As I said -- I'm happy with including a (non-technical) discussion of the ablation theory, more so than is already there, but I'm not willing to present one set of ideas as "known" when they are only represented in print by a single author, and "in print" means on the web. (BTW, if I recall, Chuck Hansen included the foam too in both of his works. My general assessment of his style was to be more confident in declassified docs than in the calculations of individuals, and the declassified docs support the foam, at least in the Morland trial). (Again, I honestly don't care either way which is "right" -- I just think you are missing an interesting and subtle point) --Fastfission 03:51, 10 August 2005 (UTC)

I never said there isn't foam there. What I said was, it's not the pusher force. Which is both supported by the fact that some fusion bombs didn't use a radiation channel liner (clearly, if it can work without the foam, it's not a necessary component...) and basic physics. We know (because it's in the DOE declassified information about fusion bombs) that various foams, foamed with methane and pentane and other stuff, are components of bomb assemblies, and from other sources we know that at least on place they're used is in the radiation channel.

We know the dimentions of the Ivy Mike internal components. If you deposit the whole primary energy into the radiation channel filler, there isn't enough force available to compress the tamper and deuterium into pressures and temperatures where it'll fuse. On the other hand, if you dump that much energy in, it will transfer energy into the tamper and case, as is well documented in open literature from IC fusion and the like. And once you start to heat the tamper/pusher, then it will start to ablate, as dense hot high-Z materials in high fermi gas and plasma conditions will ablate away and have a rocket effect, as is also well documented in the literature from IC fusion and other fields.

One way doesn't physically work, according to any component of the body of physics knowledge, and the other component will have the effect that the NW FAQ says it will if you put it next to the other one, according to the body of physics knowledge, regardless of where the energy gets initially deposited.

And from basic physics, and the open specialty literature including IC fusion, we know that low Z materials absorb X-rays less efficiently than high Z materials (you shield X-ray machines with lead, right?). So a very easy conclusion is that most of the primary's energy is going into the high Z radiation case wall and secondary tamper/pusher anyways, regardless of there being foam there or not.

This chain of logic has been written up, formally presented in the NW FAQ, and peer reviewed by professional physicists in the unclassified specialty fields in detail, and lightly and off the record by bomb designers. It passed.

If you can educate yourself enough on the physics to review it, the related fields, and then come back and find some weakness in it, please feel free to do so. But everyone who already had that knowledge who's looked at it has agreed with it. So... survey says? Georgewilliamherbert 04:53, 10 August 2005 (UTC)

I think... backing up a few steps, and laterally some, I think a categorization issue is what's going on here.

Rhodes, Morland, et al are secondary sources, and popularizations. Fastfission, you're approaching them properly as popularized science writing and not primary source science.

The NW FAQ is a piece of science and engineering primary material, which is what I think you're missing in all of this. It draws from other primary material, and while somewhat popularized rather than firmly academically rigorous at every step, it has become additional peer reviewed primary material. But you're still treating it like it was secondary material.

I've been trying to articulate aspects of this, but I think it's clearer if I back away from all the details and present the issue at this level. I hope it helps. Georgewilliamherbert 05:24, 10 August 2005 (UTC)