Talk-Polywell.org

Could anyone shed some light on consequences for polywell theory of the finding described in the following paper:

http://www.nature.com/srep/2012/121127/ ... 00889.html

Observation of inhibited electron-ion coupling in strongly heated graphite

T. G. White, J. Vorberger, C. R. D. Brown, B. J. B. Crowley, P. Davis, S. H. Glenzer, J. W. O. Harris, D. C. Hochhaus, S. Le Pape, T. Ma, C. D. Murphy, P. Neumayer, L. K. Pattison, S. Richardson, D. O. Gericke & G. Gregori

"Creating non-equilibrium states of matter with highly unequal electron and lattice temperatures (Tele≠Tion) allows unsurpassed insight into the dynamic coupling between electrons and ions through time-resolved energy relaxation measurements. Recent studies on low-temperature laser-heated graphite suggest a complex energy exchange when compared to other materials. To avoid problems related to surface preparation, crystal quality and poor understanding of the energy deposition and transport mechanisms, we apply a different energy deposition mechanism, via laser-accelerated protons, to isochorically and non-radiatively heat macroscopic graphite samples up to temperatures close to the melting threshold. Using time-resolved x ray diffraction, we show clear evidence of a very small electron-ion energy transfer, yielding approximately three times longer relaxation times than previously reported. This is indicative of the existence of an energy transfer bottleneck in non-equilibrium warm dense matter."

Slower thermalization? This is good, right?

From a laymans perspective, I doubt this study has much to do with fusion plasmas. This is in a solid matric, with high coupling between the electrons and ions. Fusion plasmas are weakly coupled. coupling relates to the local ion electron - electron interaction domahancy over space charge. The ultimate coupling would be bound atoms / molecues like H2, which is a neutral particle and does not respond to space charges like you have with the potential well in the Polywell. With charged particles there teds to be tight coupling with relatively cool and dense conditions, low coupling in hot and less dense conditions . Plasma densities of ~ 10^20 particles per M^3 is relatively low density, and temperatures of ~ 10,000 eV is hot. In the mentioned study they were using graphene, and temperatures before melting is only ~ 1 eV.

If they are saying that ion- electron interactions in this cold- dense state results in energy exchange- momentum exchange at ~ 1/3of predicted, and this translates into hot - low density states, then thermalization of electrons by ions in a Polywell would be slower, and I think this would be a good thing for Bremsstrulung, and possibly maintenance of non- thermailzed conditions.

My understanding is that the accepted energy exchange between the electrons and ions is ~ 1/60th as much as the energy exchange between like species. This is due to the square root of the relative masses (inertia or momentum of the particles). This means that ions will thermalize other ions much faster than they will thermalize electrons. This same principles apply to thermalizing (slowing) neutrons. Hydrogen works much better than lead because the relative masses/ momentum are much closer to each other. If a one mass particle hits a 10 mass particle, only 1 % of the KE is transferred to the heavier particle while 99 % of the KE is retained by the lighter particle.

One argument against the Polywell is that the ions heat the electrons too rapidly, so (I think) the electrons cannot have an temperature much different than the ions, even under local conditions. This means the two species traveling side by side spend a relatively long time close to each other and thus these local conditions predominate (coupling is greater). There are other permutations that add to the complexity. There have been arguments that this results in bipolar cusp flows (which seems wrong in a non neutral plasma that is loosely coupled- space charge effects dominate over local effects) and skepticism that deep potential wells can form.

Dan Tibbets

i'd like to add that the study seems to suggest that the observed effects where particular to graphite. as such, the results could be related to the solid crystalline structure of the material. such, of course, would not be the case in the core of a polywell, so if it really is a phenomenon particular to crystalline structure, the findings wouldn't apply. now if the casing of the magrid was made of graphite, that might make them more relevant, or if this has ramifications for superconductors...

Creating non-equilibrium states of matter with highly unequal electron and lattice temperatures

What they said above.

Lattice is not gas plasma. I do not see great relationship between the two. But if there is any relationship, I would assess it as a positive as you did.

Ok, guys. Thanks for taking time to elaborate on this. Really appreciated.