Talk-Polywell.org

Hmmm? Where did you read that?

icarus wrote:Any news on the plasmoids front?

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

Brian H wrote:

kurt9 wrote: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.

kurt9 wrote: ...

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 wrote:

icarus wrote: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.

GIThruster wrote: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.

D Tibbets wrote: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

D Tibbets wrote: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

tomclarke wrote: ...

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 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.

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.