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Talk:National Ignition Facility/Archive 1

< Talk:National Ignition Facility
Latest comment: 1 year ago by 80.215.80.31 in topic Expert review needed
Archive 1

older material

On first reading of this page, the density of 1Kg/mL without context doesn't sound all that big a deal off the top of my head. Addition of a link for the "6 times the density of the sun's core" comment, and/or a reference point of 11.34g/mL for lead, would significantly help. - Omega (aka Erik Walthinsen, omega no at spam vcolo dot com) 22:52, Dec 16, 2005 (PDT)

The targets are held in place by natural spider silk. [1] - Omegatron 19:32, Apr 28, 2005 (UTC)

Inflation

Latest comment: 18 years ago2 comments2 people in discussion

"When first proposed in the early 1990s, the cost for a "ulra laser" was estimated at less than $700 million. Current estimates put the ultimate cost between $3.5 and $6 billion."

I think it would be a good idea to place a note that adjusts the 700 million dollars for inflation. Unfortunatly, I don't know the year the cost proposal was made. If someone finds out later on, they can use an inflation calculator. If we assume 1990 and compare to 2005, its approximatly 3-6 times as originally proposed. It's still a big under estimate but its less than what one who might not think to account for inflation would believe. --Dr. Eggman3 04:20, 26 March 2006 (UTC)

Inflation between 1990 and 2000 was 34%. It explains nothing of the problem IMHO, not even the original price bump to 1.1 billion. Maury 11:58, 13 September 2006 (UTC)

Frequency upconversion

Latest comment: 18 years ago14 comments2 people in discussion

I'm still a little confused about this. Is the primary frequency of the mainline laser in the IR? Or does the laser have a few fundamentals and the upconvertor is only changing some of them (which I consider less likely)? How effecient is the process? Maury 11:51, 20 September 2006 (UTC)

Answered my own question, article updated. Maury 12:21, 20 September 2006 (UTC)
Freq. tripling of the fundamental Nd IR line to 351nm UV on NIF approaches ~50% efficiency.--Deglr6328 09:04, 21 September 2006 (UTC)

OK, that parts better. But now how much energy is lost in the UV -> x-ray "conversion"? I'd like to get a figure on the total amount of x-ray energy delivered to the target, I think that would be very useful. Maury 00:41, 3 October 2006 (UTC)

Its significant. I don't know about exact numbers because it varies hugely depending on many many factors. The only reason they bother with it of course is because of its simillarity to the Teller-Ulam radiation case. The direct drive method is way more efficient. This 1999 NIF paper [2] claims a 85% efficiency of UV to X radiation conversion efficiency.... --Deglr6328 07:06, 3 October 2006 (UTC)

I'm reading that paper now... excellent ref BTW. OK, it seems that the conversion is very good, but there's the n(abs) number which is the big one I think. Also the paper seems to suggest that the delivered power to the hohlraum is 1.8 TJ, but I'm pretty sure that's the power before conversion into UV, which as you noted is about 50%. The paper is quite confusing on this point, because they seem to change their definitions. At the top they say the laser power is 1.8 TJ, but all the charts at the bottom have 4.7 MJ or less, and it's not at all obvious what they are talking about. I'll keep reading... Maury

Thanks for all the help Deglr! I worked all of your additions and reference into a new section that I think is fairly readable. I think the article has progressed tremendously in the last month or so -- in fact I'd claim it's likely one of the best intro articles on NIF available anywhere. Perhaps we should go for a featured article attempt? Maury 15:10, 3 October 2006 (UTC)

Sure. I've really enjoyed editing it with you! I'm not sure its ready for FA nomination though. Many details still need adding. I'd say once its about a third longer and double the citations it would be about ready. --Deglr6328 01:13, 4 October 2006 (UTC)

Darn, actually there is one more missing number -- how much energy is needed to pump the amplifiers? I now have the rest of the numbers; 4 MJ of IR comes out of the beamlines, that turns into a nominal 1.8 MJ of UV after upconversion, x-ray conversion eats up just under half of that, coupling with the target is fairly efficient and should result in between 600 kJ and 1 MJ being absorbed. 25% overall, which I consider quite good! That is expected to cause an ignition that results in 100 MJ of fusion energy being released. So if we know the amount of power dumped into those flashtubes, we can estimate the overall end-to-end gain. I didn't see this in the ref, but maybe I just missed it? Maury 15:14, 3 October 2006 (UTC)

 
I think our numbers may be a bit off concerning the beam to hohlraum to target coupling efficiency....
The wall plug efficiency from electricity to 4MJ IR is just hideous. We're talking like ~1% efficient. The capacitors that fire the Xe flashlamps store an unbelievable 330MJ! [3] --Deglr6328 01:07, 4 October 2006 (UTC)
Youch. Well actually it's not that bad, they're going to get ~100 MJ back out, and with a spherical direct drive that would be more like 160 MJ if I'm running the numbers correctly. Do you know if the flashlamps fire once for each pulse? Or is there any energy left over that lets them fire a couple of pulses from a single pumping? Maury 20:16, 4 October 2006 (UTC)
They'll be lucky to get 2-3 shots off A DAY. The flashtubes fire once every 6-8 hours max. The Nd:glass heats up and becomes deformed, ruining the wavefront quality of the beam for hours after the shot until they cool down. So the sequence is: Xe lamps fire> Nd atoms into excited state population inversion > seed pulse is injected into beamline> beam is passed back and forth through the Nd glass slabs in the amp and through the spatial filter each 4 times (its switched using a PEPC[4]) to extract as much gain from the amps as possible before the pop. inversion is gone >beams are freq. converted and injected into target chamber. Remember, this all has to be done immediately when the lamps fire, the excited state decay time for Nd is like milliseconds at most (microseconds? can't remember). Do you have a link for the 160MJ number? I've never seen gain predictions that high! --Deglr6328 05:55, 5 October 2006 (UTC)

Great diagram! Now the number I had, 600 kJ -> 1 MJ, is directly quoted in one of those refs, the PDD one I think. The diagram seems to suggest a better UV-to-x-ray conversion, like 70%, and a much lower x-ray-to-capsule "delivery". Hmmm. Well at least now I clearly see why people think that magnetic confinement is the way to go! Maury 11:50, 5 October 2006 (UTC)

Oops, just saw your question there. The 160 MJ number is an estimate I made from the other numbers given in the refs. The one I mentioned in the first bit above stated that the fusion energy in the indirect drive configuration would be 100 MJ, and that was at a gain of 25. In the direct drive configuration it is expected the gain would be around 40. So I just did the conversion. I cannot find a real gain number for the saturn targets though, just "high". Maury 11:52, 5 October 2006 (UTC)

Nope, found those numbers too, the saturn targets peak around 37. So now we have direct refs for all of the gains and powers except the estimate I made above, but I believe it to be correct because the fusion power scales linearly with the gain in all of the other examples (which makes sense, because that what gain means!). Maury 12:30, 5 October 2006 (UTC)

In regards to efficiency, direct drive and fast ignition type schemes are theoretically much more efficient compared to indirect drive. While I don't have the numbers off hand, if you search the literature for "inertial confinement fast ignition" you should find some numbers. I believe the one I read a few years ago was from a Japanese Physicist. NIF is about 0.5% wall plug efficient and has theoretical rep rate between 6-8 hours. Replacing the Xe flash lamps with diodes can improve the laser driver efficiency better than an order of magnitude. For example, the MERCURY laser at LLNL is a design sutible for an ICF laser driver has demonstrated 10% wall plug efficiency and a rep rate of 10Hz. The Laser technology is steadily progressing. The logistics of target design, manufacture and delivery are probably the biggest challenges facing inertial fusion energy. Were potentially a few decades away from major break through that will make fusion energy a reality. However, I believe it's prudent to pursue both magnetic and inertial confinement.

Xenon or krypton?

Latest comment: 18 years ago3 comments2 people in discussion

Does anyone know what the gas mixture is in the flash lamps? The Xenon flash lamp article seems to imply that krypton is more likely, which might suggest a change to the article. Maury 22:13, 4 October 2006 (UTC)

Would you believe that I was JUST pondering this exact question today? I will look into it but I'm pretty sure they're mostly, if not all Xe. I think Kr is mostly used in arclamps and high rep. rate flashtubes. If the NIF tubes do have Kr I bet its only to make a penning mixture.--Deglr6328 04:37, 5 October 2006 (UTC)
I am unable to find a single refrence which says that the NIF lamps are filled with anything but Xe. --Deglr6328 05:01, 5 October 2006 (UTC)

Automated peer review

Latest comment: 18 years ago1 comment1 person in discussion

National Ignition Facility

The following suggestions were generated by a semi-automatic javascript program, and may or may not be accurate for the article in question.

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You may wish to browse through User:AndyZ/Suggestions for further ideas. -Ravedave (help name my baby) 04:38, 10 October 2006 (UTC)

References

  1. ^ See footnote
  2. ^ See footnote
  3. ^ See footnote
  4. ^ See footnote
  5. ^ See footnote
  6. ^ See footnote
  7. ^ See footnote

GA failed

Latest comment: 17 years ago1 comment1 person in discussion

I have failed this article according to the GA criteria. The article is only sourced for the last half of the article or so with entire sections for the first half lacking inline citations. Go through and add inline citations for any statements you think a reader may wonder about its verifiability. Make sure to fix up the section that has the weasel words tag and then remove it once the section is fixed. The article appears to be broad enough and has plenty of images (although see if you can space some of the beginning images out better). Once you fix these suggestions, consider renominating again or get a peer review first to get a better gauge on fixing any other issues I may have missed. If you don't agree with the review of the article, see Wikipedia:Good article review. Good job so far, and keep improving the article! --Nehrams2020 06:55, 19 March 2007 (UTC)

Shock Compression

Latest comment: 17 years ago1 comment1 person in discussion

To me it seems pretty obvious that if enough laser energy were directed at this "target" in a short enough time that the people at NIF could have a functioning nuclear bomb in their midst. In this article why is there no discussion of "shock compression"? This seems like such an obvious extension of their research.

I assume you meant to make this a new topic for the discussion.
That's what they're doing--making a controlled nuclear bomb. They direct a lot of watts (not energy) at the target. The amount of energy produced from fusion in NIF is around the number of calories in 150 candy bars (if they were burnt). So it isn't much of a bomb. 171.71.37.103 21:41, 6 June 2007 (UTC)

Good Article Review

Latest comment: 17 years ago3 comments3 people in discussion

I have re-listed this article for GA. Maury 17:34, 10 July 2007 (UTC)

Did you re-list for GA or did you only list at GA/R? If the article is listed at both, the nomination at GA/R needs to be withdrawn. LaraLoveT/C 17:54, 10 July 2007 (UTC)

The Good article review has now been archived. Good luck with the GAC. Geometry guy 22:49, 10 July 2007 (UTC)

GA on Hold

Latest comment: 17 years ago10 comments2 people in discussion
GA review (see here for criteria)
  1. It is reasonably well written.
    a (prose):   b (MoS):  
  2. It is factually accurate and verifiable.
    a (references):   b (citations to reliable sources):   c (OR):  
  3. It is broad in its coverage.
    a (major aspects):   b (focused):  
  4. It follows the neutral point of view policy.
    a (fair representation):   b (all significant views):  
  5. It is stable.
     
  6. It contains images, where possible, to illustrate the topic.
    a (tagged and captioned):   b (lack of images does not in itself exclude GA):   c (non-free images have fair use rationales):  
  7. Overall:
    a Pass/Fail:  

I have placed this GA candidate on hold for the moment. Overall, it is very well written.

  1. My main concern with the article is the lack of citations. The first citation encountered in the text is six paragraphs in. Additionally, the "NIF and ICF" and "Criticsm" sections are largely unsourced. ("Critics argue..." What critics?)
  2. I think the sheer number of images detracts from the article. Text under the first image should be cut down severely; while I understand its importance to the article, it might work better as an external link. Keep the two diagrams and the picture of the fuel capsule, they add the most to the article.
  3. Be careful about jargon, abbreviations especially. For instance, in the "Construction Problems" section, the article uses the abbreviation "LRUs" without telling what an LRU is. I think I'd also get rid of the bold words and clean up the first paragraph in the "Description" section.

Overall, I'd say you're very close though. Keep up the good work! shoy 01:10, 11 July 2007 (UTC)

The reason there are no cites in the first six paragraphs is because they consist of introductory material who's claims are re-made later (the first two) or are boilerplate text condensed from the fully refed main article (the next three) -- there is a ref in the 6th. The boilerplate is used across all of the ICF articles. The only paras below that without inlines are three in the NIF and ICF section, which, like the material above, are also historical notes and taken from fully refed articles. Every statement about the NIF itself is refed. I can't speak for the Criticsm section, not having edited any of it. Frankly, I'm not even sure it should be there, although that first statement is basically a truism. The debate between the magnetic and ICF approaches has been rancorous and ongoing for forty years now. How does one ref that though? Difficult to say,

As to the images, I really can't think of a better way to describe how the system works than use the image as a starting place -- that's why the first one ended up with so much text. It might be better served by moving this down into the Description section and simply pointing out parts with TLAs, but try as I might, I couldn't find a better lead-off image. I'm not really sure what to do about this, they're all interesting in their own right, but I would agree that together there are a lot.

I fixed LRU.

Maury 12:01, 11 July 2007 (UTC)

I added a gallery, but I haven't decided if it looks nicer or worse. Is it just me, or do galleries look poor? Maury 12:06, 11 July 2007 (UTC)

Correct me if I'm wrong, but I think that facts should be sourced the first time they're stated, but not any subsequent times. That way, it's easy for the reader to look back for the source, and they don't have to go hunting through the article. Similarly, I'd like the "boilerplate text" to be cited, even if it's just one source at the end of the paragraph. And the "Criticism" section really needs to be cited-- It may be true that there is controversy, but unless you can come up with a reliable source, Wikipedia can't say it (see WP:WEASEL). shoy 17:02, 11 July 2007 (UTC)
I think that facts should be sourced the first time they're stated, but not any subsequent times.
That's a stylistic interpretation, IMHO. If I'm going to cover the material in full fashion in the body, I put the ref there, where it is more "direct". IE, it is common to reduce entire paragraphs from the body into a single statement in the intro, placing the ref there removes much of the detail. Whereas the main body might have three paras with five refs, the intro statement might have one statement, and the five refs would be bewildering. There's no policy on this as far as I am aware, and it is by no means uncommon, every scientific paper I've ever read follows this style, for instance.
As to the critisms section, I'm happy removing it. Maury 17:41, 11 July 2007 (UTC)
I couldn't find any policy on it either. I would have written it differently, but what you've got is fine. As to the criticisms section, it really should be removed if there aren't any sources. shoy 18:18, 12 July 2007 (UTC)
Already done! (well, the offending portion anyway) Maury 21:04, 12 July 2007 (UTC)
Promoted. shoy 16:59, 13 July 2007 (UTC)

Shooting Pu or U on the NIF does not constitute a "subcritical" experiment. This erroneous statement was removed.

Ummm, what? The mass of the Pu or U is definitely subcritical! Maury 02:55, 19 July 2007 (UTC)

A "subcritical" experiment has specific goals that aren't necessarily addressed by a laser experiment which happens to utilize "subcritical" quantities of the materials. The "subcritical" reference is wildly wrong in the context of NIF experiments, for very specific reasons.

And I'm sure you'd be happy to define these "very specific reasons" and "specific goals", right? I'm not saying you're wrong, but you've offered nothing in way of support of your position. In support of mine, I point to the fact that NIF's budget and experimental schedule is dominated entirely by the NSP. I'm not convinced they consider ultra-density experiments with Pu so differently as you claim here. Maury 12:27, 19 July 2007 (UTC)

The rest of the sentence answers part of it - laser experiments are intended to provide precise equation of state (EOS) data, most importantly along a shock hugoniot (http://en.wikipedia.org/wiki/Rankine-Hugoniot_equation), for particular materials in particular parameter regimes, but subcritical explosions are intended to provide integrated weapon-specific data on performance in a fairly messy environment that can't provide precise EOS data, and doesn't need to in order to be successful. I'm not sure what "NSP" is, but the schedule and budget are dominated by ignition experiments, not by EOS experiments with nuclear materials. Just trying to be precise here.

GA review

Latest comment: 16 years ago5 comments4 people in discussion

At the risk of adding to the multitude of GA related-discussions for this article, I've asked for a Good Article Review of this article, since in my opinion it still does not satisfy requirements. Contributors and previous GA reviewers are welcome to contribute. Drewcifer3000 06:03, 22 August 2007 (UTC)

Where is the discussion? Maury 11:43, 24 August 2007 (UTC)

Corrections made on the target diameter (2 mm vs. 3) and the DT ice temperature (18+ K, not a few degrees). Invisiblemen 05:44, 10 September 2007 (UTC)

I've delisted this based on reviewers comments, but would encourage the editors to renominate the article at GAN. The main concern raised at the GAR was that some of the material in the article was not clearly traceable to reliable secondary sources in accordance with WP:RS. Geometry guy 20:52, 10 October 2007 (UTC)

The tenting material is in fact plastic webbing, not spider silk. Invisiblemen (talk) 14:00, 16 January 2008 (UTC)

On hold

Latest comment: 16 years ago14 comments3 people in discussion

So why have I put such a well written article on hold?

GA review (see here for criteria)

This is a nice piece of work, but it still has some shortcomings with respect to the good article criteria, but you can fix them easily.

  1. It is reasonably well written.
    a (prose):   b (MoS):  
  2. It is factually accurate and verifiable.
    a (references):   b (citations to reliable sources):   c (OR):  
    The sources are not sufficient to cover the whole article, take the background section with not a single citation, or the fifth paragraph in the "description" section. "NIF and ICF" has similar problems, and so did the "criticism section". This problem might give rise to allegations of OR.
  3. It is broad in its coverage.
    a (major aspects):   b (focused):  
    The article would be better if it had mentioned the people who had helped in its development a bit more.
  4. It follows the neutral point of view policy.
    Fair representation without bias:  
  5. It is stable.
    No edit wars etc.:  
  6. It is illustrated by images, where possible and appropriate.
    a (images are tagged and non-free images have fair use rationales):   b (appropriate use with suitable captions):  
  7. Overall:
    Pass/Fail:  

I will gladly pass the article if these issues are addressed. Ah, so I do not forget, please use the CITE web template for the last citations. It is important to do so, for a GA and even more so for an FA if editors are taking that way. Good luck and see you in a week. Λua∫Wise (Operibus anteire) 17:03, 15 February 2008 (UTC)

It's a little hard to read the stuff above in "edit mode", so if I miss anything I blame the markup...
"take the background section with not a single citation"
The background section is a synopsis of the same section in the ICF article. References are provided in depth there, and after much argument the general consensus is that "copying references" is not really needed.
"has similar problems"
Can you be more specific here? One of the problems is that a particular para does not have a reference, but that's definitely not a GA requirement, or didn't use to be, anyway.
"CITE web template"
Since when did this become a GA requirement? And for the love of god, why?! The internal formatting of a non-visible markup element should not be the difference between a good and non-good article, IMHO.
Maury (talk) 17:22, 21 February 2008 (UTC)
I've re-written the criticism section, I think everything is reffed now. Maury (talk) 22:23, 21 February 2008 (UTC)
Actually, do we even need that section? Perhaps the last two sections could be combined? Hmmm. Maury (talk) 00:58, 22 February 2008 (UTC)
Ok, I'm looking over it as a whole to try to get a feel for some of the extra refs you wanted. If you see any honkers put a ref-needed and I have a good idea which one it came from so I can put it in quick.
I'm also thinking of greatly shortening the background section. I looked over the one in the Migma article, and while it could use some improvement itself, it's smaller, more comprehensive, and shorter too! If you wouldn't mind looking at that one, I'm thinking it might be a good idea to bring it in here during the GA. I'd also use the same one in the various other ICF articles - Shiva laser, Nova laser, HiPER etc. Maury (talk) 01:03, 22 February 2008 (UTC)
Extending the On hold period for 2 days
The final decision (fail or pass) will be made on the 24th of February.
Okay Maury, I agree with you on some issues and disagree with you on others.
First, The citation templates are not themselves required, the information they have is. Per WP:MoS which is referred to here clearly states that WP:verifiability is one of the major criteria. How is that related to CITE templates? They are related because web sites change, providing one url to back the whole paragraph is rather unreasonable. I know they are bulky, but are necessary. I am not objecting to the first sources, but rather to sources from 11-17 except 16. Access dates and titles must be provided. Do not agree?
I saw that you have rewritten the Criticisms section, certainly better than before. :)
The background section can be rewritten to make it more comprehensive and shorter.
Per WP:LEAD, the lead should summarise the article, which it does, but I think it would be better if some citations were used there, even if the same datum is referenced in a later section.
I hope you realise that I am not applying FA criteria on a GA candidate, and I also hope that I do not have harsh criteria. For the moment, I am leaning towards a Pass, but let's see what happens.
Cheers!
Λua∫Wise (Operibus anteire) 10:19, 22 February 2008 (UTC)
Is there a tool for converting the refs to cites? Something that you point to an url, type in anything it can't figure out, and then it inserts them? Maury (talk) 14:45, 24 February 2008 (UTC)
Hmmm...I have come across some tools that can do that, I think. I will do a quick search and get back to you. Λua∫Wise (Operibus anteire) 18:01, 24 February 2008 (UTC)
Okay, could this be of any help [5]?
There is some sort of an article here which might help as well [6].
Will you finish working on this article today, or should I defer the decision till tomorrow? Λua∫Wise (Operibus anteire) 18:07, 24 February 2008 (UTC)
Ignoring the use of CITE vs. REF, is there anything else that needs work right now? Maury (talk) 22:47, 25 February 2008 (UTC)
Yes, I have put some citation needed templates, they need to be fixed. Λua∫Wise (Operibus anteire) 17:59, 26 February 2008 (UTC)

Well I'm busy working on new articles, so you can just fail this one I guess. Maury (talk) 19:20, 26 February 2008 (UTC)

  • If you're interested in really picky comments, the sentence "Its main roles will be the exploration of inertial confinement fusion and, through these experiments, exploring high-energy high-density physics and nuclear weapons for the United States." is not very well constructed (I wouldn't mention this if it wasn't so prominent, right at the top). "Exploration ... exploring" is uncomfortable, and, in any case, "exploring nuclear weapons" is probably not really what's meant. That would mean someone crawling around on top of a stockpile. It's also not absolutely clear which components the clause "for the United States" applies to. Sorry! —Preceding unsigned comment added by 86.133.48.221 (talk) 23:00, 24 February 2008 (UTC)
Yeah, I'm not a big fan of that sentence either. Hmmm... Maury (talk) 22:47, 25 February 2008 (UTC)


Failed "good article" nomination

Latest comment: 16 years ago1 comment1 person in discussion

This article failed good article nomination. This is how the article, as of February 27, 2008, compares against the six good article criteria:

1. Well written?: Pass
2. Factually accurate?: No, citations are needed. Many statements are left unsourced which could lead to accusations of OR and POV (especially in a topic of such scientific importance)
3. Broad in coverage?: Pass, although somethings need to be added per comments above.
4. Neutral point of view?: Pass
5. Article stability? Pass
6. Images?: Pass


When these issues are addressed, the article can be renominated. If you feel that this review is in error, feel free to take it have it reassessed. Thank you for your work so far.— Λua∫Wise (Operibus anteire) 14:17, 27 February 2008 (UTC)

Whoa

Latest comment: 16 years ago1 comment1 person in discussion

Aurawise posted a huge number of "cite neededs" on various locations around the article. The vast majority of these are covered in the citations already listed, often in the very same paragraph. Others are general background info that can be looked up in the articles on the ICF concept as a whole. Still others could not possibly be considered questionable (500 ps?! NEVER!). I might be verging on OWN here, but does anything else think these might be a little too much? Maury (talk) 16:41, 19 March 2008 (UTC)

Thank you LLNL!

Latest comment: 16 years ago2 comments2 people in discussion

I recently received a number of materials from LLNL, in particular Bob Hirschfeld, that have corrected a number of problems (thankfully mostly minor) and added up-to-date progress reports. Included were a considerable number of high quality references that are publicly accessible but somewhat difficult to find. I have also added a new paragraph on the new target designs, which had slipped under my radar and was a definite sin of omission. I believe the results speak for themselves. Thank you LLNL! Maury (talk) 23:55, 30 April 2008 (UTC)

This has evolved into a very nicely written and factually correct article, nice work. Invisiblemen (talk) 20:35, 25 July 2008 (UTC)

budget

Latest comment: 15 years ago1 comment1 person in discussion

I've heard other numbers, closer to 3.4 billion for the total construction costs of the project. Can anyone produce a citation? —Preceding unsigned comment added by 99.137.90.141 (talk) 23:46, 26 March 2009 (UTC)

How was location for this project determined?

Latest comment: 15 years ago2 comments2 people in discussion

I excerpt from the introduction of the article as follows:

Then they must strike within 50 micrometers of their assigned spot on a target the size of a pencil eraser. Because the precise alignment of NIF's laser beams is extremely important for successful operation, the requirements for vibrational, thermal and seismic stability are unusually demanding. Critical components, weighing tens of tons, were located to a precision of 100 microns using a rigorous engineering process for design validation and as-installed verification.

Why on earth was this built in California, the state most infamous for seismic instability (earthquakes)? Shanoman (talk) 17:25, 31 March 2009 (UTC)

Um.... proximity to Lawrence Livermore maybe? Politics? —Preceding unsigned comment added by 166.56.100.129 (talk) 19:53, 31 March 2009 (UTC)

How would the fusion energy be captured?

Latest comment: 15 years ago5 comments5 people in discussion

The article doesn't say how the energy created by ignition/fusion would be captured and distributed for use. This seems a significant omission, considering creating fusion energy for useful purposes is the main point of the facility. Dubiousraves (talk) 21:32, 1 April 2009 (UTC)

The NIF is not designed to capture energy, in the sense of electrical power generation. It's main purpose is the creation and observation of fusion reactions. Power generation is a "front" of the NIF. It's main purpose is to better understand nuclear reactions, for nuclear weapons. Since the USA is a member of the nuclear non-proliferation treaty, it's they only way to make sure the there nuclear weapons work as designed. As you may know, nuclear weapons do have a shelf life of roughly 50 years. The USA can "re-build" them, but not test them. So the NIF is the only way to test nuclear reactions, within there interpretation of the treaty... there is a lot of disagreement of the legality of the NIF. Hence why power generation, is used as a method, to discuss the operation of the NIF. You my not know this, but Hoya, a glass maker, who made the glass for the NIF lasers, has been under a boycott for some time. Power generation will be a spin-off of the NIF, but is not it's main purpose. Just to be clear, I'm not in disagreement of the NIF. I think it's quite fascinating, but I also realize its true purpose. Nebrot (talk) 10:45, 2 April 2009 (UTC)
You conflated the NNPT with the Comprehensive Test Ban Treaty. You'll need to cite sources for the above claims. Tempshill (talk) 18:05, 2 April 2009 (UTC)
I seriosly doubt the ability of this installation to get as much energy out of a reaction as it puts into it. Look at Iter, and how that structure, expected to cost over 10 billion (!) Euro, will not generate a single watt of elictricity to be distributed to consumers, because the technology is not yet there and ITER is simply a large research project. NIF is for weapons research, nothing else, and it becomes obvious when you compare it with ITER. -- DevSolar (talk) 15:18, 2 April 2009 (UTC)

I agree with the original poster that the energy capture issue isn't mentioned. That's probably because the NIF has no system for for it. However, there is a discussion of it at Inertial_confinement_fusion#Inertial_confinement_fusion_as_an_energy_source. Relevant to this article is how big of an explosion a successful test would produce. The article speaks of a hoped-for 700 tests per year. Presumably the resulting radiation, etc, would need to be contained in some manner. Are there any sources which discuss that aspect?   Will Beback  talk  21:33, 2 April 2009 (UTC)

Definition of Ignition

Latest comment: 15 years ago2 comments2 people in discussion

The definition of "ignition" (if any) used in the ICF community is not the same as that used in magnetic confinement fusion. The JASON report mentioned in the article says "Our working definition of “ignition and propagating burn” (often written simply as “achieving ignition” in this report) is a fusion energy yield at least equal to the laser energy absorbed in the target." In other words Q>1, using the terminology of magnetic confinement fusion. Note also that laser energy absorbed in the target is less than that delivered by the laser - but I don't know how much. A definition such as this really needs to go into the NIF article and other articles about ICF.194.81.223.66 (talk) 21:03, 2 April 2009 (UTC)

Odd, I just came to this page to mention the same thing. This is the first time I have heard "ignition" mean anything other than self-sustaining reactions, and suspected that it might have been a little slight-of-hand to allow a lesser goal to reached and still claim success. For instance, see this definition. In this case what the JASON report refers to is not ignition, but gain. This is also the definition used in the (somewhat disorganized) article on fusion energy gain factor here on the wiki. However, I have found several resources that suggest that both definitions are used:
The concept of ignition in fusion research is analogous to both those definitions of a fission explosion. The first definition of ignition is the creation of a self-propagating burn wave after the initial fusion reactions begin. This is a concept analogous to criticality in fission explosions. The second definition of ignition is that the energy output from the fusion reactions is more than the driver energy output (this is also called a gain of one and establishes the scientific feasibility of these devices). This is a concept analogous to fission explosions releasing more energy than the chemical high explosives used for compression.[7]
Further research would seem warranted. Maury Markowitz (talk) 12:40, 3 April 2009 (UTC)


What the heck is LASNEX?

Latest comment: 15 years ago3 comments3 people in discussion

In the "LMF and Nova Upgrade" subsection of History, I read "Based on the LASNEX computer models,...". Using "the" to refer to LASNEX implies that the term has been previously defined, but this is not the case, it springs forth from the womb full-formed. Can this be expanded to say "LASNEX computer models developed by Biff McCool at Geek Heights University" or some such explication?

Other than that (and a minor thing with pourable buildings, which I changed), I was struck by how well-written and sourced this article is. Yes, it's full of acronyms and technical terms, but after all it's a super-high-power laser facility, not a toaster. (Although, hmm, it could probably do a nice job on a slice of seven-grain bread :)

Imagine my surprise then to read the last FAC review from a year ago. I guess that's why I'm not an FA reviewer. If anyone wants to give FA another shot, I'm willing to help with fetching water and mopping sweat off brows. I personally found the article engaging and informative from start to finish. Franamax (talk) 19:13, 10 June 2009 (UTC)

LASNEX should indeed be previously defined, as there is no article on that specifically. Adding it to that sentence would probably make it poor writing, so either before or after should do. --Izno (talk) 21:24, 10 June 2009 (UTC)
LASNEX is a computer program, I will add refs.
Thanks for the kind words, all too rare here in the wiki. As to the FA, it seems it broke on the rocks of the licensing of the images. There were a whole lot of people pretending to be IP lawyers, so I just gave up. Maury Markowitz (talk) 15:02, 30 June 2009 (UTC)

NIF experiment gain question

Latest comment: 14 years ago1 comment1 person in discussion

I think the article is not clear enough on whole gain subject.

It said that whole amount of energy in capacitors is 400 MJ. Then in 3rd paragraph of 'NIF and ICF' I found that whole output supposed to be 45 MJ, at most 100 MJ.

How that correlated with media sources like this one -- http://news.bbc.co.uk/2/hi/7972865.stm

This "energy gain", as it is known, is key. If it works, NIF will release 10 to 100 times more energy than the amount pumped into the lasers to kick-start the reaction.

What does it mean? Can anyone provide explanation on NIF expected 'net gain' i.e ratio of energy output to energy input in clear form?

The article is using an artificially attractive set of numbers. They are comparing the power in the laser beam itself (1.9 MJ) to the fusion output (45 MJ). They are ignoring all the losses upstream from the beam. Actually I thought the article explained this well, but I guess it needs work. Can you offer some color on how I could improve that section? Maury Markowitz (talk) 11:18, 15 October 2010 (UTC)

Personal history

Latest comment: 14 years ago8 comments5 people in discussion

Personal history is irrelevant to the discussion of NIF.Bsure (talk) 21:03, 25 January 2010 (UTC) Bsure (talk) 21:02, 25 January 2010 (UTC)

Could you explain that remark? --Orange Mike | Talk 00:23, 26 January 2010 (UTC)

The referenced article clearly states the PhD issue had nothing to do with NIF and neither had anything to do with the resignation due to "personal reasons". 66.27.92.27 (talk) 01:20, 26 January 2010 (UTC)

Problems like this are relevant to the history of this facility, why it took so long to be built, etc. --Orange Mike | Talk 01:37, 26 January 2010 (UTC)

The referenced GAO report does not name names - it states there were "many" reasons/people responsible for incorrectly budgeting for NIF initially. The character assasination that is intent here is based solely on a newspaper article. The article clearly is mixing two events and purposely misleading the facts. I don't think there is any reason to pick "one" name and make them the fall guy for all problems based on a NYTimes article. As mentioned elsewhere in this site, a newspaper article is not a defense to libel. If you insist on blaming one individual, it seems only prudent and unbiased to include his rebuttal - why would you object to that? I think you should stick to the basic facts and stop trying to place blame on one individual. Why so much negativity? It is unbecoming to Wikipedia in my opinion! —Preceding unsigned comment added by Bsure (talk • contribs) 01:54, 26 January 2010 (UTC)

I'm rather suspicious when a brand new editor shows up on such a passionate mission, what with how people try that all the time here and they're always sure they possess the one whole truth. However I've read through some sources and I'm OK with either removing the mention of Campbell's resignation or rewriting it (and much of the section actually). The cited source goes to some length to mention "world's leading experts in ultra-high-energy beams" and how the resignation was unrelated. Other reading suggests he never actually said he had a PHD, someone in the press office started calling him Dr. Campbell and he never said not to. And the problems came to light it seems as a result of a review that he himself requested. The Nature coverage (which is regarded as, umm, reliable) does mention "resigned...ostensibly because..." but focusses much more on the problems of implementation of the science, i.e. they forgot to include space for people and/or the proponents wanted a building small enough to actually build, clean-room provisions for the project, problems with the laser glass. Other sources talk about DOE as part of the project-management problem. I'm going to randomly dump various sources here as I close the windows, partly for my own convenience: orig OM reverted [8][9][10][11] I still haven't found whatever content is in the UC review by Koonan FPR, September/October 1999, p. 57. Anyway, I do agree there is not much relevance to the statement on Campbell's resignation appearing in this article unless it's more well-qualified. The rest of the section may need some looking at too, I'm not confident the description of the GAO report tells the full story, nor whether the section adequately describes the actual problems. It seems like someone lowballed the original cost and time estimate, but the sources I've seen are rather unclear on that. Franamax (talk) 04:56, 26 January 2010 (UTC)

I agree with much of what you said - not sure what you are "suspicious" about, but let's just applaud passion when you find it...in this current climate....most just "don't bother" to put forth the effort. At any rate, the section could use more detail about the many levels of problems - this is a highly technical effort -- the first of its kind -- hopefully, we will be reading all about its ignition successes in the future, but the initial problems could be more adequately described and the eventual steps to correct them. Much of this article focuses on the problems and criticisms.....needs more balance - the facility is the first of its kind and if experimentally successful, could be a major scientific advancement with kudos to the US - etc. And by the way....I applaud your passion and thank you, and the others, for your efforts! Bsure (talk) 18:20, 26 January 2010 (UTC)

NIF is hardly "first of its kind". It is, as the history demonstrates, literally a scaled up Nova. Nova was a scaled up Shiva. These things go back to the 60's. Maury Markowitz (talk) 11:26, 15 October 2010 (UTC)

PHELIX translation

Latest comment: 14 years ago1 comment1 person in discussion

Hi there, looking for someone, who's time and courage to translate and change the German written Wikipedia PHELIX [12] in a good English article. Best Regards --Commander-pirx (talk) 11:18, 23 November 2010 (UTC) ([13]

Semi-prot

Latest comment: 13 years ago4 comments4 people in discussion

I semi'd this as we were getting IPs rewriting the article to all positive stuff. Some of the sourcing looked dodgy as well. Can I suggest that if anyone has a problem with this, please raise it here and it can be discussed. If there is anything of the edit I took out that can be rescued, feel free to do it, but I wasn't happy at wholesale removal of apparently referenced material. --John (talk) 05:55, 28 September 2011 (UTC)

Would like to remove this statement from the NIF article: "Cochran described NIF director Edward Moses and his team as snake oil salemen." This is a personal attack on Ed Moses instead of an objective comment on the project. It's also inconsistent with Wiki's policy of not making personal attacks anywhere on the site, and with Wiki's editorial guidelines of maintaining a neutral point of view and not quoting from participants engaged in a heated dispute. Thanks. JacksIrving (talk) 01:25, 6 October 2011 (UTC)

I think a better solution is to simply remove the entire section. This was leftover material from an early version of the article that I felt uncomfortable deleting because it was well refed. However, it seems to add little that isn't better covered above. If no one objects, I'll simply cut it out. Maury Markowitz (talk) 12:20, 11 October 2011 (UTC)
The NIF has been operating and firing laser beams on target for over two years now. The criticisms section made sense several years ago, when there was still a debate about building the NIF and about what it should do, but that is now old history. Invisiblemen (talk) 23:03, 29 October 2011 (UTC)

Introducing myself

Latest comment: 12 years ago1 comment1 person in discussion

I am Lynda Seaver, the media liaison for the National Ignition Facility at Lawrence Livermore National Laboratory. NIF is undergoing some significant tests recently and I think the results would be of great interest on the Wikipedia page. So in the interest of full disclosure I want to introduce myself and let folks know I will be adding some info to the NIF page. Lseaveratnif (talk) 18:50, 29 March 2012 (UTC)Lseaveratnif

Suggested edit

Latest comment: 12 years ago1 comment1 person in discussion

The last paragraph refers to the record shot NIF achieved on March 15, 2012. The energy is listed as more than 2 megajoules. While this is correct, it should be noted that the actual amount of energy into the center of the target chamber was 1.875 megajoules. This energy at target chamber center is what is needed to achieve ignition. Some energy is absorbed by the optics immediately outside the target chamber, hence the difference. Lseaveratnif (talk) 16:47, 30 March 2012 (UTC)lseaveratnif

Another section removed

Latest comment: 12 years ago5 comments4 people in discussion

There was a section headed with "Constructing NIF" that appears to be part of the major anon edits of recent times. There was some useful information in there, but reading over it it became clear it was a copy-n-paste from some external source - it referred to images that didn't exist, etc. A little googling brought me to this page, but I suspect this is scraped from another NIF page on the historical timeline. For now I've removed the text as possible copyvio, but I'd prefer to include sections of it if anyone wants to take a crack at it. Maury Markowitz (talk) 15:38, 31 October 2011 (UTC)

Happy to give that a try, and also include a bit more about how NIF is making progress toward ignition. Meanwhile, if there are no objections I'd also like to remove the last paragraph of the "Progress" section which is no longer relevant since NIF construction was completed over a year ago. JacksIrving (talk) 01:04, 15 November 2011 (UTC)

There now seems to be a section missing, with the jump from NIF Emerges to Re-Baseline and GAO Report skipping from 1994 to 2000 and the Re-Baseline section opening with "In the wake of these revelations," when no revelations are mentioned. --205.254.147.8 (talk) 15:16, 30 December 2011 (UTC)
I found several more examples of removed content that have been re-added. Maury Markowitz (talk) 18:55, 5 March 2012 (UTC)

I see this language was originally removed due to concerns regarding balance and objectivity, which is understandable. However, this same questionable language has been reinserted without addressing the issues of balance, which is counter to Wikipedia’s guidelines. For example, the information surrounding Tom Hunter’s quote under the Rebaseline and GAO Report section is misleading. Hunter was quick to clarify his statement shortly after it was leaked, and he has remained a supporter of NIF.

In the interest of correcting this, we would like to provide some additional information to balance this section, with respect to Wikipedia’s guidelines. Lseaveratnif (talk) 22:59, 20 April 2012 (UTC)Lseaveratnif


Rebaseline and GAO report edit

Latest comment: 12 years ago1 comment1 person in discussion

I have removed the paragraph "The public fighting between the various DOE labs" because it is factually inaccurate and lacks the balance called for in Wikipedia's guidelines. If someone wishes to reinstate that paragraph, it should include Tom Hunter's followup quote, which I have added, below.

Public feuding between the various Department of Energy laboratories over SSMP funding reached a peak when Los Alamos publicly attacked the facility as ill-conceived.[45] On 25 May an internal position paper signed by Sandia vice president Tom Hunter was obtained by the Albuquerque Tribune; the document argued that the NIF should be downsized so that it would not "disrupt the investment needed" in other labs.[45] However, that same day Hunter issued a statement regretting the incident: “It is not our role to take a formal public position on this issue, nor to second guess the Department of Energy…Public divisiveness between the laboratories is not helpful to finding good solutions and is counter to the approach we try to take in dealing with these important national issues.” (“More Troubled Waters for NIF,” Disarmament Diplomacy, Issue No. 47, June 2000 (http://www.acronym.org.uk/dd/dd47/47nif.htm)) Lseaveratnif (talk) 16:58, 5 May 2012 (UTC)lseaveratnif

Upcoming edits

Latest comment: 12 years ago6 comments2 people in discussion

I’ve posted some general edits recently to clarify some facts and provide additional detail about the project. There are still some sections, such as “NIF and ICF,” that could use additional technical corrections and updates, including new photos. I’ll take a pass at this section first, of course always being mindful of Wiki’s editorial guidelines. If anyone has any questions, please contact me on Talk. Lseaveratnif (talk) 19:02, 18 May 2012 (UTC)lseaveratnif

Update: Several edits have been made to clarify and provide specificity in the section "NIF & ICF". Again, if anyone has any concerns, please contact me on my talk page. Lseaveratnif (talk) 23:29, 8 June 2012 (UTC)

Update June 22, 2012: Updated "Driver Laser Section" with clarifications on propagation of laser beam and conversion process. Lseaveratnif (talk) 22:03, 22 June 2012

Update June 22, 2012: Added several NIF photos at the bottom of the entry. Lseaveratnif (talk) 22:33, 22 June 2012 (UTC)

Update: July 13, 2012: Retitled "Progress" and "Completion" sections, added management changes and updated some historical data.Lseaveratnif (talk) 00:18, 14 July 2012 (UTC)

Removed sentence in first paragraph beginning with "However" because (1) Energy is not power, they are two different things, and (2) The 500TW shot is already mentioned and referenced, with the same reference even, at the bottom of the page. Invisiblemen (talk) 14:34, 19 July 2012 (UTC)

Added recent news reports on the National Ignition Campaign. Invisiblemen (talk) 02:36, 23 September 2012 (UTC)

Status update

Latest comment: 9 years ago1 comment1 person in discussion

Taken from press release at LLNL http://www.llnl.gov/pao/news/news_releases/2005/NR-05-10-02.html

Suggestion to include in the article: http://ajw.asahi.com/article/sci_tech/technology/AJ201507280057 and http://www.ile.osaka-u.ac.jp/jp/overview/facilities/lfex.html Osaka University scientists said they fired the world's most powerful laser beam. The team at the university's Institute of Laser Engineering emitted a 2-petawatt... So "the most powerful laser to date" claim doesn't hold anymore (though the measurement in joules may be less discrepant between both). — Preceding unsigned comment added by 150.162.164.183 (talk) 18:06, 4 August 2015 (UTC)

Latest comment: 9 years ago1 comment1 person in discussion

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Controversies

Latest comment: 8 years ago1 comment1 person in discussion

I would like to see more mentions of the controversies about the motives and costs to undergo such a project and letting it run over budget without, IMO, any tangible positive results. For instance, more mentions of things that are reported in the following NYT [1] article would be beneficial to the readers.

Yves 19:34, 3 January 2016 (UTC)

Reading over it twice, I think there's a few useful tidbits for the fusion power article, but nothing about NIF specifically that I don't think we already have covered. I would like to get a copy of that report they mention though. Maury Markowitz (talk) 20:21, 25 April 2016 (UTC)

References

  1. ^ http://www.nytimes.com/2014/03/18/science/the-challenge-how-to-keep-fusion-going-long-enough.html?_r=0
Latest comment: 6 years ago1 comment1 person in discussion

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Dec 2022 laser energy consumption discrepancy

Latest comment: 1 year ago7 comments4 people in discussion

This source in the article[14] says "Powering the entire laser system used by the NIF requires more than 400 megajoules". An article from Nature [15] states "NIF’s 192 lasers consumed 322 megajoules of energy in the process.". Does anyone understand what's leading to this numerical discrepancy among sources? Other sources I can find also put it at "more than 300 megajoules" or "300"[16][17][18] Saucysalsa30 (talk) 02:25, 14 December 2022 (UTC)

I noticed that too. A bank of capacitors is charged up to store the energy and perhaps it’s not 100% efficient so the numbers might be input vs output. Andrew🐉(talk) 06:10, 14 December 2022 (UTC)

Which figure do you think should be used? From the context, the CNet article seems to speak more generally about the laser system, while the Nature article's figure is specific to this experiment. Saucysalsa30 (talk) 06:46, 14 December 2022 (UTC)
This article from September 2022 uses the formulation "less than 1 %" (He also points out that a gain of 1 does not mean the facility is generating net energy, given how little of the incoming electrical energy the laser converts into light on the target – in the case of NIF, less than 1%.). This formulation avoids unrealistic precision, but the message "the facility is not generating net energy" is still clear. --Kallichore (talk) 07:05, 14 December 2022 (UTC)
Yes exactly, the stated 1.5 gain is on the fusion reaction itself. The question is how much energy are the lasers consuming in this experiment? The Nature article gives a precise number at least. Saucysalsa30 (talk) 05:03, 15 December 2022 (UTC)
Nature's figure of 322 MJ is suspiciously close to 2.05 MJ divided by the theoretical efficiency of NIF's flashlamps, around 0.66 percent. 2.05 MJ /0.0066 = 311 MJ. As Nature notes, this facility wasn't built with any care given to electrical efficiency (it wasn't even built for fusion power experiments, not funding-wise, anyway) and it's conceivable that the lab does not even know precisely how much "wall plug" electricity is consumed. It's not in the instrumentation listed at the NIF User Guide. ☆ Bri (talk) 17:21, 15 December 2022 (UTC)
I put some notes on the origin of the 0.66 percent efficiency figure at Talk:National Ignition Facility/Laser efficiency, along with some information on how it could be improved. It might be useful for this discussion or perhaps even could be adapted for the article. ☆ Bri (talk) 03:49, 17 December 2022 (UTC)

Capacitor bank

Latest comment: 1 year ago4 comments2 people in discussion

@Mfb: According to [19], the capacitor bank supplies 2 MJ per each of the 192 modules (1 per beam) for total of 384 MJ. ☆ Bri (talk) 05:36, 17 December 2022 (UTC)

The 2 MJ is a rounded value just like the 2.2 MJ from other sources (see e.g. Status of the NIF power conditioning system for a more scientific source). It doesn't have three significant figures. Your source also mentions "nearly 400 million joules (MJ)" as total value, in agreement with the reference I added to the article and also the one linked in this comment ("400 MJ bank"). --mfb (talk) 06:01, 17 December 2022 (UTC)
Stating 400 is probably as meaningful as it can be. The user guide refers to a bunch of equipment protection oversight. I wonder though if it was overdriven for a final hurrah what could be done. It appears they are already operating outside the original 1.8 MJ design limit [20]. ☆ Bri (talk) 06:16, 17 December 2022 (UTC)
I took a harder look at the DTIC document you shared the link to. Page 1458 has the engineering data needed to compute energy capacity; however, it looks like the capacitors are somewhat variable (due to age, maybe). Using their data and the capacitor equation E=CV2/2, one obtains somewhere between 1.7 and 2.07 MJ per MESM. Perhaps they balance new modules with worn ones to average 2 MJ. ☆ Bri (talk) 06:57, 17 December 2022 (UTC)

3.14 Burning plasma achieved

Latest comment: 1 year ago2 comments2 people in discussion

Some of this section is quite confusing and possibly incorrect. It says "The material of the hohlraum was changed to diamond to increase the absorbance of secondary x-rays". The description of the process earlier in the article explains that the hohlraum produces the x-rays which are absorbed by the fuel capsule. So how does changing the material of the hohlraum alter the absorbative properties of the fuel capsule? Figure 1 in the Nature article at [125] says that the fuel capsule is made of High Density Carbon/diamond but there's no mention of it being "changed to" it. A couple of sentences later it states "The holes in the gold cylinder surrounding the capsule were shrunk to reduce energy loss". But according to the description in the article itself the gold cylinder is the hohlraum which is now apparently made of diamond so how can it still be a gold cylinder? 212.159.76.165 (talk) 13:38, 17 December 2022 (UTC)

Anon is correct, it should have said the capsule was changed to diamond, not the hohlraum, per NYT source: "The capsules containing the hydrogen are now made of diamond instead of plastic — not because diamond is stronger but because it absorbs X-rays more readily." I've made the change. ☆ Bri (talk) 14:04, 17 December 2022 (UTC)

Explicit discussion of the ignition chamber

Latest comment: 1 year ago4 comments4 people in discussion

Great article! I thought it was missing an explicit discussion of what exactly happens in the ignition chamber. Upon a successful ignition, is it expected that, say, 60% of the fuel will undergo fusion, and the result will be ... a fireball? How is the energy drained in such a way that the ignition chamber doesn't get destroyed? Tempshill (talk) 21:15, 31 March 2009 (UTC)

There does not appear to be any mention in the article about what happens to the resulting energy released from the fusion. Is the heat collected in the walls of the ignition chamber and used to drive a conventional generator, or does this particular test facility simply let the heat dissipate for now? Is this facility actually targeting break-even (electrical) energy production or is it simply a proof-of-concept device? — Loadmaster (talk) 20:51, 3 April 2009 (UTC)
NIF is purely an experimental device, and there is no attempt to gather any of the energy from the target chamber. Nor would the basic NIF design be useful for a power generating device, because the hundreds of MJ that go into the laser produce only ~30 MJ of energy. After conversion losses and such you'd be looking at 25 times as much energy in as you could get back out. There are some devices that may be able to make laser fusion practical, however, you might want to take a look at the HiPER article.
I think the idea of describing the results of the explosion is an excellent one! Doing a little conversion, I find that the 30 MJ is about the same as 5 kg of TNT. That seems like an excellent way to explain it. Maury Markowitz (talk) 23:28, 7 April 2009 (UTC)
Hi after looking at the conference announcing the break event of the 5th dec 2022 we have clear statements from the staff working at NIF that the energy is produced in many ways, like heat, but also in the form of neutrons, all they do with these neutrons is counting them. By the way that's how they know/think they achieved fusion ignition with a factor of roughly 1.5 ... but actually, they just used the math from the theory of nuclear fusion to guess how much total energy fusion energy produced during the shot. So this is in no way a proof that fusion can produce more energy than it takes, it would be a proof if we had another experiment proving the accuracy of the math and the theory. 80.215.80.31 (talk) 14:09, 19 December 2022 (UTC)

Expert review needed

Latest comment: 1 year ago7 comments6 people in discussion

After noticing the vagueness of the "net gain" claim, I made this partial improvement to the lede. However, I now feel that this article really needs a far better explanation of what is meant by the various terms: ignition, break-even, and the precise use of Fusion energy gain factor. It's clear that their use is not rigorous amd this can confuse and mislead the reader. Not familiar with this area I looked for possible starting points:

  • [21] " "scientific break-even point," where the amount of energy that comes out of the fusion reaction is equal to that which was put in by the kinetic energy from the implosion. (The energy from the laser isn't counted in the calculation). "
  • [22] one comment claims " NIF fusion scientists currently define “break-even” in a way that is 100 times easier to achieve than what the public understands when they hear the words “break-even”,"

I also found this reddit thread mentioning there is a difference between scientific break-even and engineering break-even. -84user (talk) 18:06, 8 October 2013 (UTC)

  • The way it was described by Ed Moses is that the energy from the fusion reaction was greater than the energy exerted on the hydrogen fuel by the implosion of the capsule. There are several sources of energy loss in the inertial confinement fusion process: electrical energy from the power grid charges capacitors, the capacitors dump into flash lamps, the light from the flash lamps is absorbed by the laser glass, the energy in the laser glass is released to amplify the laser, the laser is converted from infrared to ultraviolet, the ultraviolet beams are focused on the hohlraum to produce x-rays, the x-rays strike the target capsule causing it to implode, and the implosion compresses and heats the hydrogen fuel. The "scientific break-even" point is the last step of the process, but it is a significant point in the physics of the problem. — Preceding unsigned comment added by Jaromrnelson (talk • contribs) 21:07, 21 October 2013 (UTC)
    "NIF fusion scientists currently define “break-even” in a way that is 100 times easier to achieve than what the public understands when they hear the words “break-even”."
    That's a reference to the poor efficiency of the lasers (estimated by this source to be around 1%). Actually the scientific break-event conference of dec 2022 is talking of ~300MJ needed for a ~2MJ shot, so, closer to 0.6% efficiency. It's not an engineering break-event, as they state themselves in the conference. But they claim they could use lasers with around 20% efficiency, and combined with "burning" (through nuclear fusion) more than the 4% of the fuel (in ref to the shot of the 5th dec 2022) one could think the engineering break-event one step closer, but actually they stated themselves in that same conference that the whole tech path (ICF alone) is not made for engineering break-event, but an "integrated" project would be (read: magnetic confinement combined with lasers in one single device). 80.215.80.31 (talk) 14:45, 19 December 2022 (UTC)

Howdy! I'm probably not an 'expert' but I know my way around a Lawson criteria. :D I'll take a read-over and see if I can't thinker on this a bit in the upcoming days. Morg00 (talk) 03:25, 14 November 2013 (UTC)

Well, I couldn't sleep, so I tinkered it a bit tonight. Hopefully that should clear things up a bit. I also tidied up the inertial confinement article and the nuclear fusion article a bit, added a new reference, etc, to try and make all this a bit clearer. See what you think! Morg00 (talk) 04:14, 14 November 2013 (UTC)

Those who are experts in this generally won't touch it, but in truth "scientific breakeven" is a term made up out of whole cloth by Ed Moses in an attempt to lower the "breakeven/ignition" bar and generate publicity. No one in the field ever heard this term before Ed created it, and many shook their heads in amazement when they heard him use it. Significant alpha heating is an achievement, but the precise details of how this was achieved make it less important than one might at first believe, and it is a minor achievement along a long path that might someday lead to real "breakeven". In fact there is no clear threshold for "breakeven", and even 10 MJ yield would be a tiny fraction of the total amount of electrical energy used to create the implosion, but for decades ignition was defined as neutron yield > laser energy used. This happens, according to simulations, to also push the implosion core into a regime where the main fuel is significantly burned, so it makes physical sense as well. But the whole issue is tied up in posturing and politics, as one might imagine given the staggering amount of money involved. (Edit, there is some good history on this misleading statement here, http://fire.pppl.gov/ICF_Scientific_Breakeven_LLNL2.pdf) Invisiblemen (talk) 02:39, 26 December 2013 (UTC)

I'm going to remove the tag from the article. The issue outlined here is a minor point within a (very much) larger article., and the tag, IMHO, makes it look like the content is questionable when it's really just an issue over the definition of one term.
To the issue itself: I've been sent the actual publications in question. The test runs maxed out at 17 kJ of output. That compares to about 120 kJ of x-rays deposited on the capsule. In this context the term "break even" appears (but I cannot confirm) to be used in the very specific qualifier that the input energy is the energy "in the hottest part of the fuel". In other words, 120 kJ was deposited into the fuel, but some amount, say 10 kJ, was deposited in the part that fused. 17 kJ came out of that area, so they are declaring that as break-even. I can't agree with this definition and even the lukewarm responses on the part of the other labs, it appears few others do either.. Maury Markowitz (talk) 00:06, 1 April 2014 (UTC)
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