Lawaranceville E-Newsletter

[zapkitty]

Hmmm? Where did you read that?

Last post from them was about their presentation at ICOPS...

http://focusfusion.org/index.php/site/a ... _at_icops/

... and in that post the only item mentioned that could be construed as a "problem" is that some, but not all, of their shots are generating plasmoids that have much higher ion energies than theory predicts and yet are either much less dense or are much smaller in volume than theory predicts. They're looking into it, naturally.

So nothing seems to imply a "stumbling block" in that particular post... at least not yet.

[Skipjack]

Hmmm? Where did you read that?

They had posted a timeline last month that predicting some more results wit higher yields for this month. However, I read a post on their forums that Lerner is on vacation right now and so they are not doing any shots. They are using the time to fix a few glitches in their system.

[Brian H]

Any news on the plasmoids front?

They said they were on course for 3 joules fusion out this month ... hit a stumbling block?

There's an update here: http://focusfusion.org/index.php/forums/viewreply/5772/ . Doing a thorough going-over of the switches, including one (of 12) that didn't fire at all.
Lerner is on vacation, for a few weeks in July. I guess 2+ years flat-out left him in need of a recharge! I demanded to know who gave permission for that, but didn't get an answer.

Here's an update of a presentation summarizing status and projections:
http://focusfusion.org/index.php/site/a ... _at_icops/

Interesting tidbit is that plasmoids are apparently hotter and smaller than predicted.

[kurt9]

The switch control required is similar to that developed 10 years ago for PSII (plasma source ion immersion), which is essentially a pulsed-bias 3-D ion implantation technique.

I think the problem to date is the power levels they have to handle. Plus the ~10ns response time required. Pick one! Though custom built switches appear to be getting within tolerable range.

That is a demanding application. When we did PSII in the late 90's, there was a cottage industry that had grown up mostly in the Albuquerque area to develop and sell the switches and other elements necessary for PSII (there were several efforts to develop PSII at the time, including one at Los Alamos). I think some of this technology would be useful for any pulsed fusion scheme, including Lerner's.

[Brian H]

...

That is a demanding application. When we did PSII in the late 90's, there was a cottage industry that had grown up mostly in the Albuquerque area to develop and sell the switches and other elements necessary for PSII (there were several efforts to develop PSII at the time, including one at Los Alamos). I think some of this technology would be useful for any pulsed fusion scheme, including Lerner's.

Well by all means weigh in on one of the threads like http://focusfusion.org/index.php/forums/viewthread/370/ , or email Aaron Blake (partner in LPP) ablake@lawrencevilleplasmaphysics.com or Eric elerner@igc.org or call (732) 356-5900, or even use the LPP contact form http://lawrencevilleplasmaphysics.com/i ... &Itemid=88

They are very open, even eager to discuss technical issues with those having relevant expertise (the switches, electrodes, and capacitors etc. in particular, they being so crucial and where there is so much "technical art" to survey and pick from.)

[tomclarke]

Any news on the plasmoids front?

They said they were on course for 3 joules fusion out this month ... hit a stumbling block?

There's an update here: http://focusfusion.org/index.php/forums/viewreply/5772/ . Doing a thorough going-over of the switches, including one (of 12) that didn't fire at all.
Lerner is on vacation, for a few weeks in July. I guess 2+ years flat-out left him in need of a recharge! I demanded to know who gave permission for that, but didn't get an answer.

Here's an update of a presentation summarizing status and projections:
http://focusfusion.org/index.php/site/a ... _at_icops/

Interesting tidbit is that plasmoids are apparently hotter and smaller than predicted.

It is too early to say - we must just hope that every single thing goes as planned or better, and they get their Q >1

The current anomalous figures are slightly worrying, since hotter & smaller/less dense is neutral for Q now, but as temperatures increase it will be bad for Q. Their device can increase T relatively easily, it is getting dense large plasma that is the real challenge.

But it is great they have this ambitious timeline - I am agog to see how well they can implement it.

[GIThruster]

You sure, Tom? I thought they want high temp and small confinement of the plasma. I was reading the news as lower than expected brem.

[tomclarke]

You sure, Tom? I thought they want high temp and small confinement of the plasma. I was reading the news as lower than expected brem.

Actually I am NOT sure.

But I don't think at these very low temperatures that Brem is an issue - that will be when they crank up the temp. They are still on D-T, at temperatures low enough that Q ~ T^2

[D Tibbets]

I presume you mean D-D fuel. D-T is orders of magnitude more expensive and complex as the tritium is highly radioactive and requires careful radiation handling and monitoring.
Also, with D-D if they are reaching temperatures of ~ 40-50 KeV the crossection curve is starting to level out.

Dan Tibbets

[Brian H]

I presume you mean D-D fuel. D-T is orders of magnitude more expensive and complex as the tritium is highly radioactive and requires careful radiation handling and monitoring.
Also, with D-D if they are reaching temperatures of ~ 40-50 KeV the crossection curve is starting to level out.

Dan Tibbets

Yes, the DD regime is intended as validation of pinch theory; the intent seems to be to move to p-B11 by this fall some time. I suspect that they are riding the knife edge of funding use, pushing for the maximum payoff scientifically from each use of time and resources.

I am not privy to the money flows, but the indications are that results so far have indeed begun to generate a virtuous circle of increased backing. If the pB11 works out as intended, that should start the (private) funding onto the steeper slopes of an exponential climb. Here's hoping!

[tomclarke]

I presume you mean D-D fuel. D-T is orders of magnitude more expensive and complex as the tritium is highly radioactive and requires careful radiation handling and monitoring.
Also, with D-D if they are reaching temperatures of ~ 40-50 KeV the crossection curve is starting to level out.

Dan Tibbets

Yes - I forget...

Anyway - current temps are v low low cf what is needed for p-B Q=1, so brems will not be significant loss factor yet.

EDIT - I must stop posting things I have not properly researched.

The dependence of brems on T is relatively low - between T^(1/2) and T.

However the dependence on Zi^2 means a factor of 25X greater brems when using p-B11.

So I think I stand by brems loss not being significant in current LPP experiment plasmoid temperature. But no doubt I will be corrected by those more knowledgable than me...

[Brian H]

...

However the dependence on Zi^2 means a factor of 25X greater brems when using p-B11.

So I think I stand by brems loss not being significant in current LPP experiment plasmoid temperature. But no doubt I will be corrected by those more knowledgable than me...

The LPP hypothesis is that there exists a 'quantum gap' in the energy bands where ions are unable to accelerate electrons to X-ray emitting velocity. From the patent:

The higher atomic change, Z, of B11 greatly increases the x-ray emission rate, which is proportional to Z.sup.2 making it difficult to achieve ignition, e.g., the point at which the thermonuclear power exceeds the x-ray emission. The present invention overcomes these difficulties using a detailed quantitative theory of the plasma focus, described below, and the high magnetic field effect (HMFE). This effect, first pointed out by McNally, involves the reduction of energy transfer from the ions to the electrons in the presence of a strong magnetic field. This in turn reduces the electron temperature and thus the bremsstrahlung emission.

[Aeronaut]

http://focusfusion.org/index.php/site/category/C30/ provides links to Lerner's Technical Papers I and II, which lay out the theory and math in a far more readable form than the patent text.

Technical Paper I describes the HMFE in detail. Something about relative motion, but I lack the physics training to understand it beyond that.

[Brian H]

Here's an excerpt of a reply by an LPP principal to one of my questions:

Brian, without going into details or complicated formulas, the pinches are not “hot” enough yet, but the extrapolations are there. However, pB11 is a completely different animal than deuterium.

... the results we have gotten are very encouraging, and we’re only getting started. We’re at the cutting edge of this research. With the upgraded switches, we should have vastly improved performance by having all capacitors discharge, with better synchronization, at higher voltages. We’ve barely started to test the effects of the angular momentum coil or the magnetic field effect, so we really can’t say just how much those will ultimately improve the results. We’re also getting all the diagnostic instruments installed and the noise eliminated, so we can better see what’s going on, effectively taking off [our] blindfold. As for finding the “sweet spots”, well, that’s what batting practice is all about. ... I’m very optimistic that by late September, we’ll have some newsworthy results. When all the pieces come together at the right time and place, that’s when things get interesting.

[Brian H]

Here's a LPPX summary for the latest reports:
http://focusfusion.org/index.php/site/a ... -_summary/

D/L the full PDF if you want all of it; there are excerpts posted on the site (check the sequential links at the bottom, e.g. to http://focusfusion.org/index.php/site/a ... se_plasma/ )

Lots of gritty detail about the switches and components.