Re: Future baby nukes (boffin-sized?)

From: John Clark (
Date: Fri Oct 13 2000 - 22:28:52 MDT

Michael S. Lorrey <> Wrote;

> Is it absolutely necessary to use a fission reaction to trigger a fusion reaction,

No, but it's not knows if you can trigger one strong enough worthy of the name
"bomb" without fission.

>or are other means just not feasible for an easily deployable warhead?
> I was reading about how shrimp have been discovered to produce 5000 degree
> sonoluminescent bubbles with their claws via cavitation, and I am wondering how
> much research has been done in using shaped charges or other acoustical focusing
> methods to generate fusion reactions.

They've gotten much higher temperatures than that from sonoluminescent bubbles, at least
50,000 degrees and possibly as high as one million, still too low for fusion but pretty amazing,
it's not clear how it works. It's very hard to measure the temperature because at those
temperatures the main product is X rays and they're strongly absorbed by water.

> If as you say, the mass defect is only 2 or 3 times greater, doesn't that mean you should
>be able to acheive such a reaction with enough high explosives?

I mean that a fusion bomb would be 2 or 3 times as powerful as a fission bomb with an
equal mass of fuel. I think there is little hope of achieving fusion with chemical explosives.

>How much more energy does the clean D-H3 reaction require over
>non-clean D-T reaction?

About 10 times.

> OK. How easily does this radioactivity work its way through materials?

The main target for the neutron bomb (a H bomb with the smallest possible fission trigger)
was tanks because the metal armor gave little protection against neutrons. The military
found that the best way to add protection is to place bladders on the tanks filled with a
solution of water and 20 mule team borax. Boron is very good at absorbing neutrons but
not the super fast type produced from a H bomb, you've got to slow them down. Iron or lead
is poor at slowing them down because the nucleus of those elements is so much heavier than
the neutron that when they collide the neutron just bounces off the nucleus with its speed hardly
changed. But the nucleus of hydrogen in water is almost the same mass as a neutron so when
they collide much of the neutron's energy is transferred to the hydrogen and the neutron slows
down. When the neutron slows enough the boron will absorb it. You'd need a foot or two of this
water boron solution to be effective.

         John K Clark

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