Significance of first shots and pinch, and note on process

Posted by Rezwan on Nov 05, 2009 at 09:45 AM
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Eric Lerner summarizes the significance of first shots and pinch as follows:

The achievement of a pinch, and on the second shot, means that we have accomplished one of the eight technical goals of the current experimental program. The machine is doing what we designed it to do, which is to transfer energy into a tiny plasmoid. It is quite unusual for a DPF to pinch right way. Normally fine-tuning of the electrodes and insulator and “conditioning” of the electrodes by several shots is required. That this was not needed is confirmation that our electrode and insulator dimensions, derived from LPP’s quantitative theory of DPF functioning, are accurate.

This summary helped to clarify something for me.  It appears that going through the “fire” sequence is only counted as a “shot” when everything works and the machine doesn’t misfire. 

The “down time” the crew has been experiencing stems from various components in the machine which prevent the “shot” from going off as it should.  The whole machine, in a sense, has to be fine tuned to eliminate leaks and losses and bring the charge to bear along the electrodes with the correct timing, and keep the gas in the vacuum. 

Various components such as the vacuum, switches, triggers and so forth have been assembled, disassembled, tweaked, re-assembled. 

Consider the vacuum chamber.  It has many vulnerable points - there are “windows” for observation and connecting diagnostic instruments.  Each connection point represents some vulnerability.  Every time they change something, they have to test the vacuum again.  There’s a big table in the room with FoFu, covered with tools.  I visit the lab, and the guys are in there, switching out a rogowski coil from the drift tube, for example.  Re-connecting it.  Testing the vacuum again.  This is why the machine was designed as it is, with access to walk in under the machine and constantly take things off and add things on.

The clarification for me from Eric’s statement above is that the concept of “conditioning” pertains to the electrodes, not to getting the whole machine running consistently, as I had thought.  And the good news is, the electrodes are conditioned.

The other clarification is that the “down time” is a regular part of the process of these experiments as each sequence of shots will require fitting something new to the machine for diagnostics, and also as each shot runs enormous energy through the components - with the possibility of damaging or loosening something in the process.  Perhaps, rather than “conditioning” we can talk of “tuning” the machine, and how it falls out of tune as changes are made when you play it.  So, there will be constant tuning.

It’s a time consuming process, very detail oriented. 

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There are (12) comments.

Brian H's avatar

Very interesting; it would/will be interesting too to know what output and results each of the instruments being “plugged in” provide as the year goes on.

I believe it is a good idea not to “witness against himself”, and not to disclose any raw data until the experiment is refined.

Brian H's avatar

What about the deuterium shots today? Did they light the fuse?  smile cheese  LOL  cool smile

Brian H's avatar

Disagree. Either the basic model and hypothesis is valid, and the evidence will accumulate that this is so, or it is not. What would be the value of pushing an invalid hypothesis?

I believe that it is possible to loose a lot of credibility for a valid hypothesis if the initial data is released that does not represent the best conditions for the experiment, or maybe because of some faulty equipment producing inaccurate results.
While it might not hinder the current testing itself, the loss of credibility might be a problem in the future - getting the acceptance of scientific peers or approving funding for a final prototype.

This is why PR is not a trivial thing to do (i think).
PS: I see a lot relevance to this concept:

Brian H's avatar

Yoiks! 48 minutes. Sorry. Not in the schedule.

I think your concern about wobbly early data is overdone. Far worse is attempting, or appearing to attempt, to filter and cook the results. The latter is very common, and becoming notorious in the literature, with research suggesting that over 50% of research reports are based on fudged, faked, or carefully selected data.  In almost all fields, not just the notorious social ‘sciences’. 

So I put far more value on demonstrable honesty and transparency than on prettified data sets.

While I disagree with you I understand your position. I am not aware of the situation in the scientific world so I cannot know which approach is more rewarding.
Here is something nice to read:

Brian H's avatar

That’s a very interesting article, Breakable! I can’t access the full current text, but the earlier preliminary posting at is very thorough. I’ve forwarded both to Eric, with the following excerpt:

“It’s so antithetical to the way scientists are trained,” Duke University geneticist Huntington F. Willard said at the April 2007 North Carolina Science Blogging Conference, one of the first national gatherings devoted to this topic. The whole point of blogging is spontaneity—getting your ideas out there quickly, even at the risk of being wrong or incomplete. “But to a scientist, that’s a tough jump to make,” says Willard, head of Duke’s Institute for Genome Sciences & Policy. “When we publish things, by and large, we’ve gone through a very long process of drafting a paper and getting it peer reviewed. Every word is carefully chosen, because it’s going to stay there for all time. No one wants to read, ‘Contrary to the result of Willard and his colleagues…’.”

Still, Willard favors blogging. As a frequent author of newspaper op-ed pieces, he feels that scientists should make their voices heard in every responsible way possible. Blogging is slowly beginning to catch on; because most blogs allow outsiders to comment on the individual posts, they have proved to be a good medium for brainstorming and discussions of all kinds. Bradley’s UsefulChem blog is an example. Paul Bracher’s Chembark is another. “Chembark has morphed into the water cooler of chemistry,” says Bracher, who is pursuing his Ph.D. in that field at Harvard University. “The conversations are: What should the research agencies be funding? What is the proper way to manage a lab? What types of behavior do you admire in a boss? But instead of having five people around a single water cooler you have hundreds of people around the world.”

I pointed out that having some or many knowledgeable people world-wide professionally and personally invested and inspired by participating in a research Wiki would have a very robust protection function as well as providing a great deal of competent unpaid help!

DerekShannon's avatar

Extraordinary claims require extraordinary evidence requires extraordinary repeatability requires extraordinary consistency requires extraordinary refinement requires extraordinary instrumentation requires extraordinary coordination requires extraordinary calibration requires extraordinary prudence requires extraordinary patience!

Brian H's avatar

Nah. 10 seconds of 5GW output answers all.  cheese cool grin

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