From: mbk@lyapunov.ucsd.edu (Matt Kennel)
Newsgroups: sci.physics.fusion
Subject: Re: The H-Bomb secret is out
Date: 2 Oct 1992 18:06:07 GMT
Organization: Institute For Nonlinear Science, UCSD
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mbk@lyapunov.ucsd.edu (Matt Kennel) writes:
: <This is Hans Bethe writing>
: "It is difficult to describe to a non-scientist the novelty of the new
: concept.  I was entirely unexpected from the previous development.
: It was also not anticipated by Teller, as witness his despair immediately
: preceeding the new concept.  ....  The new concept was to me, who
: had been rather closely associated with the program, about as surprising
: as the discovery of fission had been to physicists in 1939.

If this is the case, there must be something besides just
``radiation pressure'' involved.  I can't imagine them sitting around
in 1951, and slapping their head and saying ``Oh my god, we forgot
about the photons!''

In fact in 1942 they were probably thinking, "Ok we need to squeeze the stuff
together.  What do we have?   Let's see, we have neutrons, but they probably
won't interact enough to do the trick.  We have fluid(matter), which is surely
going to press on things, and we have photons."

So, what would be really surprising?  Here's a couple totally off
the wall guesses (i.e. almost certainly wrong, but you get the idea)

1)  Neutrino physics.  The detonation wave in a supernova is driven
by neutrino pressure...no bull!
I think this is extremely unlikely though.

2) <slightly more realistically>.  In ICF literature it's stated that it's
necessary to squeeze the fusion fuel to nearly Fermi degeneracy.  Certainly
in an H-bomb, that can be accomplished.  So what happens when something
becomes Fermi degenerate?  Anything really odd happens with the equation
of state?  

Now, once this big wad of stuff becomes Fermi degenerate (which means the
electrons, of course), it won't want to be compressed any more.  Or will
it?  I think that once that happens, the electrons will become *transparent*
to the photons, and not interact at all.  I.e., if you hit an electron with
a photon (x-ray) you'd have to put it in a new state, but all the states
(below some large cutoff energy) are already filled!  So, now all the
radiation pressure is acting solely on the nuclei.  (this is where
"radiation pressure" is important, as fluid pressure {electrons from matter}
can't get through because there's nowhere to put the electrons) The nuclei
are now being squeezed by the radiation, in addition to flying together
because they carry almost all the inertia from the implosion.  And remember
their electrostatic repulsion is screened by negative charge with density of
a white dwarf star.

What happens if you keep on squeezing them?  Hmm.  Deuterium nuclei
are bosons, and not fermions, and if you squeeze them enough, some might
Bose condense, in which case their wavefunctions will overlap the
bejeezus with each other, and ...


-Matt Kennel  		mbk@inls1.ucsd.edu
-Institute for Nonlinear Science, University of California, San Diego
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