Re: [Vo]:Re: HUP-spread-out electron "feels" (and thus Coulomb-screens?) like a point charge... - T.GIF

[Robin van Spaandonk]

In reply to  Michel Jullian's message of Sat, 26 Apr 2008 14:36:24 +0200:
Hi,
[snip]
>Hi Robin, many thanks for your corrections.
>
>Indeed momentum p is the denominator of the De Broglie wavelength h/p, my 
>mistake. So in fact the more immobile the target deuteron, the less close the 
>incident deuteron needs to get in order to fuse...

This is also the way I used to think, however it is somewhat problematic. In
order to tunnel, a particle has to "make an attempt", i.e. it has to move at
least a little. Furthermore, the more frequent the attempts, the more likely
tunneling is in any given period of time. (However maybe the zero point motion
is enough to count as an attempt?) - Anyone know how to calculate the frequency?

>
>1/ Wouldn't it therefore dramatically improve things if we threw (by 
>electrolysis, gas discharge or whatever) the incident deuterons onto a 
>deep-cooled deuteron desorbing cathode? (liquid deuterium in a back side 
>chamber could provide the deuterium, the low temp and the pushing pressure 
>maybe)

IIRC, there were a few early attempts using loaded cathodes rapidly immersed in
liquid nitrogen (with a few neutrons detected if I'm not mistaken).

>
>2/ Another thought triggered by your correction, forced cooling or not, isn't 
>a deuteron about to desorb (for Jones's entertainment: stuck half way through 
>the surface Pd "sphincter") particularly immobile due to its squeezed 
>condition, and therefore an easier fusion target?

I wouldn't think *anything* is particularly "stuck" at the atomic level.

>
>3/ I have found this 2002 paper "Study on Physical Foundation of Cold Fusion" :
>http://www.swip.ac.cn/cfs/english/Information/nb2002/024.2.pdf
>The English is very poor but the physics seem quite understandable, even to 
>this QM ignoramus. I find the "volcano section view" shaped potential curve 
>quite helpful: positive hill shape is Coulomb repulsion potential (hill is 
>lowered and narrowed by any screening negative charge density I guess), narrow 
>central pit going down to very negative values is nuclear force attraction 
>potential.
>   Summary of my understanding of this paper: in order to fuse i.e. fall into 
> the pit an incident deuteron doesn't have to classically go all the way up 
> the hill, instead it can tunnel through it if it gets closer than the 
> target's De Broglie wavelength. It seems the incident deuteron can be treated 
> as a classical point charge loosing KE and gaining PE to find how high on the 
> hill --and therefore how close to the target deuteron-- it gets.
>   Your comments on the paper or my summary welcome.
>
>4/ Do you have a ref for your factor 10 to 20 (0.035 to 0.07 Å instead of D2's 
>0.7 Å separation) required for practical D-D fusion power production?

Sorry, but that's based upon my own (possibly wildly inaccurate) calculations.
(See attached gif, which contains one of my various attempts to get this right).
Z = atomic number of the target nucleus
d = initial distance before tunneling
m = mass of tunneling particle
(assuming that tunneling particle has an atomic number of 1).

See also the paper:- "Catalysis of Nuclear Reactions between Hydrogen Isotopes
by mu- Mesons" by J.D. Jackson, Physical Review, Vol. 106, Number 2, April 15
1957, page 330.

Regards,

Robin van Spaandonk

The shrub is a plant.

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