...from a nuclear physicist, if that counts for anything.
First off, Robert, I would LOVE to argue stellar physics with you-- your
premise that the Sun runs on "ordinary hydrogen" is correct, but you've
failed to realize what "ordinary hydrogen" IS. It's mostly protium, but
there's a plenty large enough trace percentage of deuterium and tritium
in it to let a deuteron+deuteron=alpha+gammas reaction take place. The
fusion drives in Traveller refine fuel to eliminate nonhydrogen atoms,
and what's left is only partly deuterium, but that part is plenty to get
a good reaction going. If you want abundances, energy yields per atom,
etc., I suppose I could post them, but let's not get ridiculous. The
primary difference between protium and deuterium, the presence of a neutron,
makes all the difference between fusion and fizzle. If all you had was
protium, you'd need to combine a four-object collision that has a vanishingly
small reaction cross section with electron capture and other weak interactions.
Not impossible. Possibly even practical, in a plasma bath the size of a star.
But with deuterium around in as much quantity as it is, why bother?
And the reaction really takes off if there's tritium involved... the problem
there is that we get extra neutron flux, i.e. hard radiation. But I suggest
that we leave this part of the rules alone-- my next post, which will appear
tonight or tomorrow, will have (among other things) what a real fusion
reactor's yield is predicted to be, and how fusion would work if I were
running this universe-- excerpts from the proceedings of a FASCINATING
conference on fusion that took place recently.....
metlay