At 01:56 PM 3/23/2010, OrionWorks - Steven V Johnson wrote:
A question for the Vort Collective:
Does the use of the term "Fusion" HAVE to imply there must exist a
mechanism or process that directly overcomes the Coulomb barrier - by
brute force?
Absolutely not. Muon-catalyzed fusion does it through shielding of
the Coulomb repulsion.
Other mechanisms may exist, i.e., F-P effect fusion or other kinds,
but they all somehow "overcome" the Coulomb barrier. Like, eh,
obvious? Neutron activation overcomes the Coulomb barrier by bringing
in the positively charged package that can become a proton, together
with what can become an electron. Normally neutron activation isn't
called "nuclear fusion," the fuller term, because a neutron isn't
considered a "nucleus," but that's actually a confusing distinction,
it is better to think of it as the nucleus of an element called
"neutronium," Atomic number 0, Mass number 1.
But any black box which takes in deuterium and outputs helium has got
to have a fusion mechanism, and nobody knowledgeable will dispute
that, I believe.
If the black box dismantles the deuterium into pure energy and
somehow reassembles it all in a flash as helium nuclei, it's
accomplished nuclear fusion. That really should be very simple.
Could "fusion" also be used to explain a mechanism or process, a
process that is not yet understood and as such is still being debated,
processes that seem to ignore and/or completely side-step the dreaded
Coulomb Barrier issue?
"Fusion" describes a result, and it's an error to consider it a
process as such.
The Coulomb barrier is the force that exists between two objects with
the same charge. Here it is the normal positive charge of a nucleus.
So mashing two nuclei together by brute force, called "thermonuclear
fusion," because of the very high forces, i.e. high temperatures,
involved, directly overcomes the Coulomb barrier by climbing it, not
by reducing it in some way. Muon-catalyzed fusion accomplishes fusion
by the capture of muon by a positive nucleus, which becomes a muonic
atom, i.e., a positive nucleus orbited by a muon instead of an
electron. Muons are much heavier than electrons, so the groudn state
orbital radius is much smaller, i.e., the muon is much closer to the
nucleus than an electron would be. The assemblage (nucleus/muon,
nucleus/electron) is neutrally charged. This doesn't help ordinary
nuclei with electrons to approach closely another positive nucleus,
because the radius is so large -- unless it's a below-ground (Mills)
electron, if such exist! However, with muon shielding, the associated
nucleus can approach closely enough that the nuclear forces take over
and pull the fusing nucleus in, overcoming the remaining Coulomb barrier.
Neutron activation overcomes the Coulomb barrier by carrying the
fusing nuclear material in a tight package where the positively
charged and negatively charged elements ("proton and electron") are
tightly bound. Neutrons with high energies don't normally fuse, I
believe, they cause recoil, they bounce, or they cause immediate
breakup (as with the C-12 breakup caused by energetic neutrons of
"triple track" fame). However, slow neutrons can stick around long
enough to be absorbed into a nucleus, hence they do create a new
element with mass number bumped by one, and if the nucleus emits an
electron (beta decay), the result is that the added neutron converts,
effectively, into a proton, and the charge on the nucleus is bumped
up by one, while the mass number stays the same. (Electrons weigh
very little compared to protons). The result is quite the same, as
far as nucleus resulting, as if a proton had been fused with the nucleus.
Bose-Einstein condensates are, I believe, neutral, they are molecular
assemblages where the individual atoms lose their individual
identity. I know little about them. But it is being proposed by
Takahashi and Kim, if I'm correct, that such condensates might be
able to fuse with other nuclei, if they are small enough or under
conditions, and I'm now out on a limb where I know little....
Other approaches to fusion could involve somehow enhancing quantum
tunneling, where a particle passes through, as it were, a barrier
that is otherwise insurmountable at the energies involved, through
the statistical probability that the particle exists on the other
side. Again, my knowledge is shallow, but tunneling is a known
phenomenon with practical applications in, for example, electronics,
i.e., a tunnel diode.
2-body quantum mechanical calculations predicted that tunneling would
not occur at a frequency to be of significance to cold fusion;
however, this is the very problem: the math of quantum mechanics is
an approximatino valid under assumptions that might break down in the
condensed matter environment, and Fleischmann's research was not
aimed, originally, at solving the world's energy problems. It was
aimed at testing the limits of quantum mechanics for the prediction
of condensed matter nuclear behavior, and he expected to fail.
I'm grateful that he tried. Aren't you? What was really crazy about
the rejection was that it was based on unproven theory, a theory that
had simply been assumed to be true and where exceptions weren't
obvious. Nobody had actually *tested* the theory until Fleischmann
and Pons tried.
I could be wrong on this point (and please correct me if I am) but
I've gotten the impression that many if not most scientists believe
"fusion" MUST involve a mechanism that DIRECTLY overcomes the dreaded
Coulomb barrier.
Well, it's an obvious error. Just state it explicitly. Directly
overcoming the barrier is hot fusion. Cold fusion is, duh! Not Hot
Fusion. It's something else. What is it? Or, first of all, does it
exist? You can't prove it doesn't exist by saying it's not hot fusion.
Note that some early theories were that, indeed, it was hot fusion,
i.e., fractofusion or sonofusion.
I'm under the impression that to come up with any
other explanation or theory that attempts to introduce a mechanism
that finesses its way around the dreaded CB would NOT be considered a
legitimate theory.
Like muon-catalyzed fusion?
Which is accepted, definitely. So why not some other kind of
catalyzed or assisted fusion?
Three Nobel prize winners, at the time, considered that it was
possible something could cause fusion to take place at room
temperatures. Edward Teller immediately came up with his
Meshuggatron, a hypothesized particle. Some reading this have assumed
that he was ridiculing CF researchers. Apparently not. He was
actually trying to explain it.
