Could we perhaps break the usual rules on this blog and have somebody
post the actual facts related to the "deuterium EOS" issue? What
actually happened, or didn't happen that was supposed to?
It would be acceptable to accompany the facts with the usual diatribe, but maybe put that in a separate paragraph?
Scooby's note: what the heck is "deuterium EOS:?
It would be acceptable to accompany the facts with the usual diatribe, but maybe put that in a separate paragraph?
Scooby's note: what the heck is "deuterium EOS:?
Comments
Absolute Equation of State Measurements on Shocked Liquid Deuterium up to 200 GPa (2 Mbar)
L. B. Da Silva, P. Celliers, G. W. Collins, K. S. Budil, N. C. Holmes, T. W. Barbee Jr., B. A. Hammel, J. D. Kilkenny, R. J. Wallace, M. Ross, and R. Cauble
Lawrence Livermore Laboratory, Livermore, California 94550
A. Ng and G. Chiu
University of British Columbia, Vancouver, British Columbia, Canada
We present results of the first measurements of density, shock speed, and particle speed in liquid deuterium compressed by laser-generated shock waves to pressures from 25 to 210 Gpa (0.25 to 2.1 Mbar). The data show a significant increase in D2 compressibility above 50 Gpa compared to a widely used equation of state model. The data strongly suggest a thermal molecular dissociation transition of the diatomic fluid into a monatomic phase.
http://www.aps.org/programs/honors/prizes/prizerecipient.cfm?last_nm=Da%20Silva&first_nm=Luiz&year=1998
http://www.aps.org/programs/honors/prizes/prizerecipient.cfm?last_nm=Celliers&first_nm=Peter&year=1998
http://www.aps.org/programs/honors/prizes/prizerecipient.cfm?last_nm=Cauble&first_nm=Robert&year=1998
First, time is not cited. Verified theories can take decades or centuries.
The second is aging, ideas age and are superceded by new techniques and information as he eons pass.
Third is loss, some information is lost over time. One wonders what is lost from the ancient Alexandrian library of an almost complete set of ancient Greek texts.
The most germane is that the process involves many errors, that is where the insights are discovered. In the errors. Most ongoing experiments have been or will be updated so that they more correctly isolate the phenomena under study. In other words, if the designers has known what they know now, they would have approached the problem differently.
No surprize that Z data conflicts with/updates/illustrates with Nova. Should happen again on NIF on NIF Upgrade on Z upgrade ad nauseum. The way to stop this progess is to stop looking.
They are putting resources into EoS and high pressure strength experiments according to my understanding. I know that I speak for many others when I say that I look forward to evaluating the results and the raw data coming out of these unclassified experiments. If they are TRULY able to compress materials along the isentrope to produce EoS data with error bars smaller than from other methods, then they certainly deserve great credit for that kind of accomplishment.
And NOW we are back to do more laser EoS experiments on a bigger laser and each shot is enormously expensive. I never really appreciated this connection until now, and I think I understand why someone or a group is someone's were bringing this up quite a bit.
Equation of State Measurements in Liquid Deuterium to 70 GPa
M. D. Knudson, D. L. Hanson, J. E. Bailey, C. A. Hall, J. R. Asay, and W. W. Anderson
Phys. Rev. Lett. 87, 225501 – Published 8 November 2001
Cited 134 times
Using intense magnetic pressure, a method was developed to launch flyer plates to velocities in excess of 20km/s. This technique was used to perform plate-impact, shock wave experiments on cryogenic liquid deuterium ( L-D2) to examine its high-pressure equation of state. Using an impedance matching method, Hugoniot measurements were obtained in the pressure range of 30–70GPa. The results of these experiments disagree with previously reported Hugoniot measurements of L-D2 in the pressure range above ∼40GPa, but are in good agreement with first principles, ab initio models for hydrogen and its isotopes.
Use of a Wave Reverberation Technique to Infer the Density Compression of Shocked Liquid Deuterium to 75 GPa
M. D. Knudson, D. L. Hanson, J. E. Bailey, C. A. Hall, and J. R. Asay
Phys. Rev. Lett. 90, 035505 – Published 24 January 2003
Cited 65 times
Principal Hugoniot, reverberating wave, and mechanical reshock measurements of liquid deuterium to 400 GPa using plate impact techniques
M. D. Knudson, D. L. Hanson, J. E. Bailey, C. A. Hall, J. R. Asay, and C. Deeney
Phys. Rev. B 69, 144209 – Published 29 April 2004
Cited 76 times
Time-resolved optical spectroscopy measurements of shocked liquid deuterium
J. E. Bailey, M. D. Knudson, A. L. Carlson, G. S. Dunham, M. P. Desjarlais, D. L. Hanson, and J. R. Asay
Phys. Rev. B 78, 144107 – Published 21 October 2008
Cited 14 times
If EoS and strength are truly the focus area of stockpile stewardship, as people seem to be implying, then this D2 information is highly troubling. Two of the three legs (fusion power production, ignition) have been knocked out by the recent failures. The only remaining leg that keeps it standing with respect to life-support is stockpile stewardship. But not, people are saying that even there, that last leg supporting NIF is very weak.
Is this 1997 paper out of the lab simply a one-off fluke? Were there other laser EoS published papers out of the lab that are considered to be high-quality by the academic standards? It's hard to imagine that there is a systemic problem from a lab that receives many billions of dollars in funding over a decade in support of the stockpile to be having the kinds of problems that people are implying here.
December 4, 2012 7:23 PM
The poster is right! It's like the cure for cancer. Don't be condemning all cancer researchers now because they didn't find a cure!
In a model or code, you not only have the physics included, but you also need additional information regarding how a material will behave, for example, under different local conditions of temperature and stress. So Pressure = f (Density, Temperature) is a simple example of an "equation of state" that one needs for a material.
EoS plays an important part in the stockpile stewardship. Since we are relying on computer codes and modeling, the push is to experimentally determine equation of state in regimes (e.g., pressure, density, temperature) previously inaccessible. It was the early papers out of Sandia (I forgot the names, but maybe some can help me here) that demonstrated the ability to produce high-quality Equation of State data at high pressures, using a concept called isentropic compression, that made this area a focal point of NNSA science. I believe that it was soon after, that LLNL and others began to try to use the same techniques to generate equation of state data but using lasers as the driver. There is another way, including the use of gas guns, with impactors designed to attempt to produce the kinds of "ramp-waves" needed in order to compress a material along the isentrope.
And so it does seem to be a valid question regarding these older deuterium results, and whether there are technical weaknesses either to the analytical capabilities of the authors or to the laser-based technique itself. Either way, we need closure on the issue and assurances that indeed moving forward on lasers-based EoS is based on sound technical arguments and a solid scientific foundations.
I did not expect this!
Regarding the comments on the error bars, I'm not sure what is being implied here, but if the error bars are large, I would not be surprised given the somewhat greater complexity of the laser-drive concept and all the physics involved. A feature of the pulsed power concept is that it is inherently easier to control the force profile on the flyer.
So if the problem is not with the investigators, but rather, related to the technique, then I would also have to conclude that using NIF to support stockpile stewardship experiments in this way, is questionable.
December 5, 2012 1:25 PM
No, of course not. Let's blame the taxpayers for being dumb or stupid enough to pay for this contraption (NIF).
Some facilities like DARHT are important for the stockpile stewardship mission. That's what they were built for in the first place. Other facilities, like NIF and LANSCE, have a dubious position when it comes to their usefulness to maintaining the weapons stockpile. They were built for political reasons (management promotion, fun "toys" to use in esoteric physics experiments, etc).
Deuterium EoS is just one issue. Material strength is a whole other topic that congress and the public should be aware of.
Isn't it amazing how in the media, these two words act so well as topical "black holes?" Basically an article moves on to other things, after bringing up "stockpile stewardship."
Journalists are smart enough to understand and report on these types of issues. They should all be informed of threads like this, so that the can verify information and come up with further questions themselves, and add more substance to their own contributions to public discourse.
Any attempt to portray these events as a natural part of the discovery process is simply propaganda. This is a common practice at the lab - to silence employees who raise legitimate technical and scientific issues that management deems to be inconvenient or not in support of its agendas.
Deuterium EOS is a full case study in itself for those studying organizational structures and organizational behavior.
If someone can recall the name of the LLNL employee that was blackballed, I would appreciate it. This was a truly shameful injustice that the lab management committed.
http://physics.aps.org/authors/william_nellis
Shock compression of deuterium near 100 GPa pressures.
Nellis WJ.
Source: Lawrence Livermore National Laboratory, University of California, 94550, USA.
Abstract
The shock-compression curve (Hugoniot) of D2 near 100 GPa pressures (1 Mbar) has been contro-versial because the two published measurements have limiting compressions of fourfold and sixfold. Our purpose is to examine published experimental results to decide which, if either, is probably correct. The published Hugoniot data of low-Z diatomic molecules have a universal behavior. The deuterium data of Knudson et al. (fourfold limiting compression) have this universal behavior, which suggests that Knudson et al. are correct and shows that deuterium behaves as other low-Z elements at high temperatures. In D2, H2, N2, CO, and O2, dissociation completes and average kinetic energy dominates average potential energy above approximately 60 GPa. Below approximately 30 GPa, D2, H2, N2, CO, and O2 are diatomic. D2 dissociation is accompanied by a temperature-driven nonmetal-metal transition at approximately 50 GPa.
Blinders, chastity belt, thermal gloves and "shoes that GRIP!". Just wearing blinders doesn't cut it any longer.
Summarizing the facts of the thread: some measurements were made at LLNL, some other measurements were made at SNL, and they don't agree. That's all. Everything else is "i heard this" and "I bet that", with a large quantitiy of unsupported adjectives.
bah
Bill Nellis is a giant in the field of shock physics. The Nova guys were amateurs.
And so the scientist who was able to bring some clarity and closure to this issue is blackballed by the lab instead, while the "amateurs" are rewarded. We can do a google search of some of those names to see what plum assignments they have gotten since.
NNSA was formed in 2000? So the start of the fiasco was pre-NNSA obviously. Indeed many people in NNSA now are familiar with this incident, as they were at the labs and were working on equation of state related work. It's a good thing that many of those people are in NNSA now (as opposed to the authors of the ill-fated 1997 LLNL paper).
Oh that already happened. Bill Nellis was the first in line for a good ole fashioned lynching
Some of the same cast of characters are leading technical work on NIF. If your assertion that this one paper is a fluke, then history will have confirmed that. We have a 15 year period over which to confirm that indeed, this one paper is a fluke.
Some of the same cast of characters are leading technical work on NIF.
December 7, 2012 9:20 PM
So you think that publishing one erroneous set of data should be grounds for disallowing all further professional advancement? Or just advancement in one's chosen field? Or to management thereof? The degree of conspiracy theory, vindictive, punitive desire, and outright hate on these NIF threads is amazing. So much sturm und drang for so little substance. What a hell-hole of twisted egos. Get a clue: NIF and the whole subject of ICF or laser-driven anything matters not one whit to anyone except you pin-heads. Especially not taxpayers whose hard-earned money funds your sandbox playtime.
Keep up your little defense. It'll be more dramatic that way when someone is defending the lab.
But the scientific community already knows the answer to this. We don't need you to tell us what we already know - that they don't have the "critical mass" of scientific leadership in these fields. This is your "head shot" for the media to see, isn't it.
That's for sure. Somewhere there is an org chart floating around for NIF and WCI to find the EoS and Strength groups. Correlate that information with journal databases to see for yourself.
The NIF construction project, valued at about $3.5B, was completed two years ago. It was successful. The laser works brilliantly (pun intended). Whatever mistakes or mastery in leadership (I take some credit here) has been mooted by time. A lesson learned is that a 500Mw, 1.8Tw, blue laser composed of 180 beams with pointing and timing accuracy that can paint a "bb" with DT targets three times a day with adequate diagnostics and a skilled staff to understand the events cost +/- $3.5B not $1.8B. Two destroyers not one. Old news. Wildly successful.
A more accurate target for your "technical leadership" shot is the management of the much smaller current experimental program probably now under 500 people and $250M per year. Significant but much smaller.
To be credible, you need to keep your facts straight. Otherwise, you solve the wrong problem. No need to manage the NIF project. It's over.
I consulted with a colleague just now who mentioned the existence of a third modelling paper (maybe an internal report only?) out of the lab whose data also sits on top of the incorrect results, but I could not find this reference.
December 8, 2012 12:02 AM: With 6 billion dollars at stake on the NIF facility, the authors of that 1997 article are fair game.
You did not go far enough here. With 6B at stake, the technical leads of all the experimental efforts related to NIF are also fair game and it is our duty to scrutinize their track record of scientific contributions and peer-reviewed journal publications in those fields.
To think that this is all about a single paper snowballing into a fiasco is shortsighted. The 1997 paper is simply the tip of the iceberg.
Byline: "We never cared about that stuff anyways, we just wanted the money to support ignition and LIFE." Lab then throws its own EoS and Materials Strength scientists under the bus as human sacrifice to appease the gods with several pounds of flesh. Lab then discredits its own EoS and strength programs, further justifying a focus on ignition for NIF.
there's no business like snow business.